Add pysh, ply, and codegen to lib/ to prepare for future work

(Bitbake rev: d0a6e9c5c1887a885e0e73eba264ca66801f5ed0)

Signed-off-by: Chris Larson <chris_larson@mentor.com>
Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>

9 files changed, 4138 insertions, 0 deletions

diff --git a/bitbake/lib/pysh/__init__.py b/bitbake/lib/pysh/__init__.py
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/bitbake/lib/pysh/__init__.py
diff --git a/bitbake/lib/pysh/builtin.py b/bitbake/lib/pysh/builtin.py
new file mode 100644
index 0000000000..25ad22eb74
--- /dev/null
+++ b/bitbake/lib/pysh/builtin.py
@@ -0,0 +1,710 @@
+# builtin.py - builtins and utilities definitions for pysh.
+#
+# Copyright 2007 Patrick Mezard
+#
+# This software may be used and distributed according to the terms
+# of the GNU General Public License, incorporated herein by reference.
+
+"""Builtin and internal utilities implementations.
+
+- Beware not to use python interpreter environment as if it were the shell
+environment. For instance, commands working directory must be explicitely handled
+through env['PWD'] instead of relying on python working directory.
+"""
+import errno
+import optparse
+import os
+import re
+import subprocess
+import sys
+import time
+
+def has_subprocess_bug():
+    return getattr(subprocess, 'list2cmdline') and \
+       (    subprocess.list2cmdline(['']) == '' or \
+            subprocess.list2cmdline(['foo|bar']) == 'foo|bar')
+            
+# Detect python bug 1634343: "subprocess swallows empty arguments under win32"
+# <http://sourceforge.net/tracker/index.php?func=detail&aid=1634343&group_id=5470&atid=105470>
+# Also detect: "[ 1710802 ] subprocess must escape redirection characters under win32"
+# <http://sourceforge.net/tracker/index.php?func=detail&aid=1710802&group_id=5470&atid=105470>
+if has_subprocess_bug():
+    import subprocess_fix
+    subprocess.list2cmdline = subprocess_fix.list2cmdline
+
+from sherrors import *
+
+class NonExitingParser(optparse.OptionParser):
+    """OptionParser default behaviour upon error is to print the error message and
+    exit. Raise a utility error instead.
+    """
+    def error(self, msg):
+        raise UtilityError(msg)
+
+#-------------------------------------------------------------------------------  
+# set special builtin
+#-------------------------------------------------------------------------------  
+OPT_SET = NonExitingParser(usage="set - set or unset options and positional parameters")
+OPT_SET.add_option( '-f', action='store_true', dest='has_f', default=False,
+    help='The shell shall disable pathname expansion.')
+OPT_SET.add_option('-e', action='store_true', dest='has_e', default=False,
+    help="""When this option is on, if a simple command fails for any of the \
+    reasons listed in Consequences of Shell Errors or returns an exit status \
+    value >0, and is not part of the compound list following a while, until, \
+    or if keyword, and is not a part of an AND or OR list, and is not a \
+    pipeline preceded by the ! reserved word, then the shell shall immediately \
+    exit.""")
+OPT_SET.add_option('-x', action='store_true', dest='has_x', default=False,
+    help="""The shell shall write to standard error a trace for each command \
+    after it expands the command and before it executes it. It is unspecified \
+    whether the command that turns tracing off is traced.""")
+
+def builtin_set(name, args, interp, env, stdin, stdout, stderr, debugflags):
+    if 'debug-utility' in debugflags:
+        print interp.log(' '.join([name, str(args), interp['PWD']]) + '\n')
+
+    option, args = OPT_SET.parse_args(args)
+    env = interp.get_env()
+    
+    if option.has_f:
+        env.set_opt('-f')
+    if option.has_e:
+        env.set_opt('-e')
+    if option.has_x:
+        env.set_opt('-x')
+    return 0
+    
+#-------------------------------------------------------------------------------  
+# shift special builtin
+#-------------------------------------------------------------------------------  
+def builtin_shift(name, args, interp, env, stdin, stdout, stderr, debugflags):
+    if 'debug-utility' in debugflags:
+        print interp.log(' '.join([name, str(args), interp['PWD']]) + '\n')
+        
+    params = interp.get_env().get_positional_args()
+    if args:
+        try:
+            n = int(args[0])
+            if n > len(params):
+                raise ValueError()
+        except ValueError:
+            return 1
+    else:
+        n = 1
+        
+    params[:n] = []
+    interp.get_env().set_positional_args(params)
+    return 0
+    
+#-------------------------------------------------------------------------------  
+# export special builtin
+#-------------------------------------------------------------------------------  
+OPT_EXPORT = NonExitingParser(usage="set - set or unset options and positional parameters")
+OPT_EXPORT.add_option('-p', action='store_true', dest='has_p', default=False)
+
+def builtin_export(name, args, interp, env, stdin, stdout, stderr, debugflags):
+    if 'debug-utility' in debugflags:
+        print interp.log(' '.join([name, str(args), interp['PWD']]) + '\n')
+        
+    option, args = OPT_EXPORT.parse_args(args)
+    if option.has_p:
+        raise NotImplementedError()
+    
+    for arg in args:
+        try:
+            name, value = arg.split('=', 1)
+        except ValueError:
+            name, value = arg, None
+        env = interp.get_env().export(name, value)
+    
+    return 0
+    
+#-------------------------------------------------------------------------------  
+# return special builtin
+#-------------------------------------------------------------------------------  
+def builtin_return(name, args, interp, env, stdin, stdout, stderr, debugflags):
+    if 'debug-utility' in debugflags:
+        print interp.log(' '.join([name, str(args), interp['PWD']]) + '\n')
+    res = 0
+    if args:
+        try:
+            res = int(args[0])
+        except ValueError:
+            res = 0
+        if not 0<=res<=255:
+            res = 0
+            
+    # BUG: should be last executed command exit code        
+    raise ReturnSignal(res)
+
+#-------------------------------------------------------------------------------  
+# trap special builtin
+#-------------------------------------------------------------------------------  
+def builtin_trap(name, args, interp, env, stdin, stdout, stderr, debugflags):
+    if 'debug-utility' in debugflags:
+        print interp.log(' '.join([name, str(args), interp['PWD']]) + '\n')
+    if len(args) < 2:
+        stderr.write('trap: usage: trap [[arg] signal_spec ...]\n')
+        return 2
+
+    action = args[0]
+    for sig in args[1:]:
+        try:
+            env.traps[sig] = action
+        except Exception, e:
+            stderr.write('trap: %s\n' % str(e))
+    return 0
+
+#-------------------------------------------------------------------------------  
+# unset special builtin
+#-------------------------------------------------------------------------------
+OPT_UNSET = NonExitingParser("unset - unset values and attributes of variables and functions")
+OPT_UNSET.add_option( '-f', action='store_true', dest='has_f', default=False)
+OPT_UNSET.add_option( '-v', action='store_true', dest='has_v', default=False)
+
+def builtin_unset(name, args, interp, env, stdin, stdout, stderr, debugflags):
+    if 'debug-utility' in debugflags:
+        print interp.log(' '.join([name, str(args), interp['PWD']]) + '\n')
+        
+    option, args = OPT_UNSET.parse_args(args)
+    
+    status = 0
+    env = interp.get_env()
+    for arg in args:    
+        try:
+            if option.has_f:
+                env.remove_function(arg)
+            else:
+                del env[arg]
+        except KeyError:
+            pass
+        except VarAssignmentError:
+            status = 1
+            
+    return status
+
+#-------------------------------------------------------------------------------  
+# wait special builtin
+#-------------------------------------------------------------------------------  
+def builtin_wait(name, args, interp, env, stdin, stdout, stderr, debugflags):
+    if 'debug-utility' in debugflags:
+        print interp.log(' '.join([name, str(args), interp['PWD']]) + '\n')
+
+    return interp.wait([int(arg) for arg in args])
+
+#-------------------------------------------------------------------------------  
+# cat utility
+#-------------------------------------------------------------------------------
+def utility_cat(name, args, interp, env, stdin, stdout, stderr, debugflags):
+    if 'debug-utility' in debugflags:
+        print interp.log(' '.join([name, str(args), interp['PWD']]) + '\n')
+
+    if not args:
+        args = ['-']
+
+    status = 0
+    for arg in args:
+        if arg == '-':
+            data = stdin.read()
+        else:
+            path = os.path.join(env['PWD'], arg)
+            try:
+                f = file(path, 'rb')
+                try:
+                    data = f.read()
+                finally:
+                    f.close()
+            except IOError, e:
+                if e.errno != errno.ENOENT:
+                    raise
+                status = 1
+                continue
+        stdout.write(data)
+        stdout.flush()
+    return status
+    
+#-------------------------------------------------------------------------------  
+# cd utility
+#-------------------------------------------------------------------------------  
+OPT_CD = NonExitingParser("cd - change the working directory")
+
+def utility_cd(name, args, interp, env, stdin, stdout, stderr, debugflags):
+    if 'debug-utility' in debugflags:
+        print interp.log(' '.join([name, str(args), interp['PWD']]) + '\n')
+
+    option, args = OPT_CD.parse_args(args)
+    env = interp.get_env()
+    
+    directory = None
+    printdir = False
+    if not args:
+        home = env.get('HOME')
+        if home:
+            # Unspecified, do nothing
+            return 0
+        else:
+            directory = home
+    elif len(args)==1:
+        directory = args[0]
+        if directory=='-':
+            if 'OLDPWD' not in env:
+                raise UtilityError("OLDPWD not set")
+            printdir = True
+            directory = env['OLDPWD']
+    else:
+        raise UtilityError("too many arguments")
+            
+    curpath = None
+    # Absolute directories will be handled correctly by the os.path.join call.
+    if not directory.startswith('.') and not directory.startswith('..'):
+        cdpaths = env.get('CDPATH', '.').split(';')
+        for cdpath in cdpaths:
+            p = os.path.join(cdpath, directory)
+            if os.path.isdir(p):
+                curpath = p
+                break
+    
+    if curpath is None:
+        curpath = directory
+    curpath = os.path.join(env['PWD'], directory)
+
+    env['OLDPWD'] = env['PWD']
+    env['PWD'] = curpath
+    if printdir:
+        stdout.write('%s\n' % curpath)
+    return 0
+
+#-------------------------------------------------------------------------------  
+# colon utility
+#-------------------------------------------------------------------------------  
+def utility_colon(name, args, interp, env, stdin, stdout, stderr, debugflags):
+    if 'debug-utility' in debugflags:
+        print interp.log(' '.join([name, str(args), interp['PWD']]) + '\n')
+    return 0
+    
+#-------------------------------------------------------------------------------  
+# echo utility
+#-------------------------------------------------------------------------------  
+def utility_echo(name, args, interp, env, stdin, stdout, stderr, debugflags):
+    if 'debug-utility' in debugflags:
+        print interp.log(' '.join([name, str(args), interp['PWD']]) + '\n')
+        
+    # Echo only takes arguments, no options. Use printf if you need fancy stuff.
+    output = ' '.join(args) + '\n'
+    stdout.write(output)
+    stdout.flush()
+    return 0
+    
+#-------------------------------------------------------------------------------  
+# egrep utility
+#-------------------------------------------------------------------------------
+# egrep is usually a shell script.
+# Unfortunately, pysh does not support shell scripts *with arguments* right now,
+# so the redirection is implemented here, assuming grep is available.
+def utility_egrep(name, args, interp, env, stdin, stdout, stderr, debugflags):
+    if 'debug-utility' in debugflags:
+        print interp.log(' '.join([name, str(args), interp['PWD']]) + '\n')
+        
+    return run_command('grep', ['-E'] + args, interp, env, stdin, stdout, 
+        stderr, debugflags)
+    
+#-------------------------------------------------------------------------------  
+# env utility
+#-------------------------------------------------------------------------------  
+def utility_env(name, args, interp, env, stdin, stdout, stderr, debugflags):
+    if 'debug-utility' in debugflags:
+        print interp.log(' '.join([name, str(args), interp['PWD']]) + '\n')
+    
+    if args and args[0]=='-i':
+        raise NotImplementedError('env: -i option is not implemented')
+    
+    i = 0
+    for arg in args:
+        if '=' not in arg:
+            break
+        # Update the current environment
+        name, value = arg.split('=', 1)
+        env[name] = value
+        i += 1
+        
+    if args[i:]:
+        # Find then execute the specified interpreter
+        utility = env.find_in_path(args[i])
+        if not utility:
+            return 127
+        args[i:i+1] = utility
+        name = args[i]
+        args = args[i+1:]
+        try:
+            return run_command(name, args, interp, env, stdin, stdout, stderr, 
+                debugflags)
+        except UtilityError:
+            stderr.write('env: failed to execute %s' % ' '.join([name]+args))
+            return 126            
+    else:
+        for pair in env.get_variables().iteritems():
+            stdout.write('%s=%s\n' % pair)
+    return 0
+    
+#-------------------------------------------------------------------------------  
+# exit utility
+#-------------------------------------------------------------------------------
+def utility_exit(name, args, interp, env, stdin, stdout, stderr, debugflags):
+    if 'debug-utility' in debugflags:
+        print interp.log(' '.join([name, str(args), interp['PWD']]) + '\n')
+        
+    res = None
+    if args:
+        try:
+            res = int(args[0])
+        except ValueError:
+            res = None
+        if not 0<=res<=255:
+            res = None
+            
+    if res is None:
+        # BUG: should be last executed command exit code
+        res = 0
+        
+    raise ExitSignal(res)
+
+#-------------------------------------------------------------------------------  
+# fgrep utility
+#-------------------------------------------------------------------------------
+# see egrep
+def utility_fgrep(name, args, interp, env, stdin, stdout, stderr, debugflags):
+    if 'debug-utility' in debugflags:
+        print interp.log(' '.join([name, str(args), interp['PWD']]) + '\n')
+        
+    return run_command('grep', ['-F'] + args, interp, env, stdin, stdout, 
+        stderr, debugflags)
+
+#-------------------------------------------------------------------------------  
+# gunzip utility
+#-------------------------------------------------------------------------------
+# see egrep
+def utility_gunzip(name, args, interp, env, stdin, stdout, stderr, debugflags):
+    if 'debug-utility' in debugflags:
+        print interp.log(' '.join([name, str(args), interp['PWD']]) + '\n')
+        
+    return run_command('gzip', ['-d'] + args, interp, env, stdin, stdout, 
+        stderr, debugflags)
+    
+#-------------------------------------------------------------------------------  
+# kill utility
+#-------------------------------------------------------------------------------
+def utility_kill(name, args, interp, env, stdin, stdout, stderr, debugflags):
+    if 'debug-utility' in debugflags:
+        print interp.log(' '.join([name, str(args), interp['PWD']]) + '\n')
+        
+    for arg in args:
+        pid = int(arg)
+        status = subprocess.call(['pskill', '/T', str(pid)],
+                                shell=True,
+                                stdout=subprocess.PIPE,
+                                stderr=subprocess.PIPE)
+        # pskill is asynchronous, hence the stupid polling loop
+        while 1:
+            p = subprocess.Popen(['pslist', str(pid)],
+                                shell=True,
+                                stdout=subprocess.PIPE,
+                                stderr=subprocess.STDOUT)
+            output = p.communicate()[0]
+            if ('process %d was not' % pid) in output:
+                break
+            time.sleep(1)
+    return status
+    
+#-------------------------------------------------------------------------------  
+# mkdir utility
+#-------------------------------------------------------------------------------
+OPT_MKDIR = NonExitingParser("mkdir - make directories.")
+OPT_MKDIR.add_option('-p', action='store_true', dest='has_p', default=False)
+
+def utility_mkdir(name, args, interp, env, stdin, stdout, stderr, debugflags):
+    if 'debug-utility' in debugflags:
+        print interp.log(' '.join([name, str(args), interp['PWD']]) + '\n')
+        
+    # TODO: implement umask
+    # TODO: implement proper utility error report
+    option, args = OPT_MKDIR.parse_args(args)
+    for arg in args:
+        path = os.path.join(env['PWD'], arg)
+        if option.has_p:
+            try:
+                os.makedirs(path)
+            except IOError, e:
+                if e.errno != errno.EEXIST:
+                    raise
+        else:               
+            os.mkdir(path)
+    return 0
+
+#-------------------------------------------------------------------------------  
+# netstat utility
+#-------------------------------------------------------------------------------
+def utility_netstat(name, args, interp, env, stdin, stdout, stderr, debugflags):
+    # Do you really expect me to implement netstat ?
+    # This empty form is enough for Mercurial tests since it's
+    # supposed to generate nothing upon success. Faking this test
+    # is not a big deal either.
+    if 'debug-utility' in debugflags:
+        print interp.log(' '.join([name, str(args), interp['PWD']]) + '\n')
+    return 0
+    
+#-------------------------------------------------------------------------------  
+# pwd utility
+#-------------------------------------------------------------------------------  
+OPT_PWD = NonExitingParser("pwd - return working directory name")
+OPT_PWD.add_option('-L', action='store_true', dest='has_L', default=True,
+    help="""If the PWD environment variable contains an absolute pathname of \
+    the current directory that does not contain the filenames dot or dot-dot, \
+    pwd shall write this pathname to standard output. Otherwise, the -L option \
+    shall behave as the -P option.""")
+OPT_PWD.add_option('-P', action='store_true', dest='has_L', default=False,
+    help="""The absolute pathname written shall not contain filenames that, in \
+    the context of the pathname, refer to files of type symbolic link.""")
+
+def utility_pwd(name, args, interp, env, stdin, stdout, stderr, debugflags):
+    if 'debug-utility' in debugflags:
+        print interp.log(' '.join([name, str(args), interp['PWD']]) + '\n')
+
+    option, args = OPT_PWD.parse_args(args)        
+    stdout.write('%s\n' % env['PWD'])
+    return 0
+    
+#-------------------------------------------------------------------------------  
+# printf utility
+#-------------------------------------------------------------------------------
+RE_UNESCAPE = re.compile(r'(\\x[a-zA-Z0-9]{2}|\\[0-7]{1,3}|\\.)')
+
+def utility_printf(name, args, interp, env, stdin, stdout, stderr, debugflags):
+    if 'debug-utility' in debugflags:
+        print interp.log(' '.join([name, str(args), interp['PWD']]) + '\n')
+        
+    def replace(m):
+        assert m.group()
+        g = m.group()[1:]
+        if g.startswith('x'):
+            return chr(int(g[1:], 16))
+        if len(g) <= 3 and len([c for c in g if c in '01234567']) == len(g):
+            # Yay, an octal number
+            return chr(int(g, 8))
+        return {
+            'a': '\a',
+            'b': '\b',
+            'f': '\f',
+            'n': '\n',
+            'r': '\r',
+            't': '\t',
+            'v': '\v',
+            '\\': '\\',
+        }.get(g)
+        
+    # Convert escape sequences
+    format = re.sub(RE_UNESCAPE, replace, args[0])
+    stdout.write(format % tuple(args[1:]))
+    return 0
+    
+#-------------------------------------------------------------------------------  
+# true utility
+#-------------------------------------------------------------------------------
+def utility_true(name, args, interp, env, stdin, stdout, stderr, debugflags):
+    if 'debug-utility' in debugflags:
+        print interp.log(' '.join([name, str(args), interp['PWD']]) + '\n')
+    return 0
+
+#-------------------------------------------------------------------------------  
+# sed utility
+#-------------------------------------------------------------------------------
+RE_SED = re.compile(r'^s(.).*\1[a-zA-Z]*$')
+
+# cygwin sed fails with some expressions when they do not end with a single space.
+# see unit tests for details. Interestingly, the same expressions works perfectly
+# in cygwin shell.
+def utility_sed(name, args, interp, env, stdin, stdout, stderr, debugflags):
+    if 'debug-utility' in debugflags:
+        print interp.log(' '.join([name, str(args), interp['PWD']]) + '\n')
+        
+    # Scan pattern arguments and append a space if necessary
+    for i in xrange(len(args)):
+        if not RE_SED.search(args[i]):
+            continue
+        args[i] = args[i] + ' '
+
+    return run_command(name, args, interp, env, stdin, stdout, 
+        stderr, debugflags)
+
+#-------------------------------------------------------------------------------  
+# sleep utility
+#-------------------------------------------------------------------------------
+def utility_sleep(name, args, interp, env, stdin, stdout, stderr, debugflags):
+    if 'debug-utility' in debugflags:
+        print interp.log(' '.join([name, str(args), interp['PWD']]) + '\n')
+    time.sleep(int(args[0]))
+    return 0
+    
+#-------------------------------------------------------------------------------  
+# sort utility
+#-------------------------------------------------------------------------------
+OPT_SORT = NonExitingParser("sort - sort, merge, or sequence check text files")
+
+def utility_sort(name, args, interp, env, stdin, stdout, stderr, debugflags):
+
+    def sort(path):
+        if path == '-':
+            lines = stdin.readlines()
+        else:
+            try:
+                f = file(path)
+                try:
+                    lines = f.readlines()
+                finally:
+                    f.close()
+            except IOError, e:
+                stderr.write(str(e) + '\n')
+                return 1
+        
+        if lines and lines[-1][-1]!='\n':
+            lines[-1] = lines[-1] + '\n'
+        return lines
+    
+    if 'debug-utility' in debugflags:
+        print interp.log(' '.join([name, str(args), interp['PWD']]) + '\n')
+        
+    option, args = OPT_SORT.parse_args(args)
+    alllines = []
+    
+    if len(args)<=0:
+        args += ['-']
+        
+    # Load all files lines
+    curdir = os.getcwd()
+    try:
+        os.chdir(env['PWD'])
+        for path in args:
+            alllines += sort(path)
+    finally:
+        os.chdir(curdir)
+            
+    alllines.sort()
+    for line in alllines:
+        stdout.write(line)
+    return 0
+    
+#-------------------------------------------------------------------------------
+# hg utility
+#-------------------------------------------------------------------------------
+
+hgcommands = [
+    'add',
+    'addremove',
+    'commit', 'ci',
+    'debugrename',
+    'debugwalk',
+    'falabala', # Dummy command used in a mercurial test
+    'incoming',
+    'locate',
+    'pull',
+    'push',
+    'qinit',
+    'remove', 'rm',
+    'rename', 'mv',
+    'revert',    
+    'showconfig',
+    'status', 'st',
+    'strip',
+    ]
+
+def rewriteslashes(name, args):
+    # Several hg commands output file paths, rewrite the separators
+    if len(args) > 1 and name.lower().endswith('python') \
+       and args[0].endswith('hg'):
+        for cmd in hgcommands:
+            if cmd in args[1:]:
+                return True
+            
+    # svn output contains many paths with OS specific separators.
+    # Normalize these to unix paths.
+    base = os.path.basename(name)
+    if base.startswith('svn'):
+        return True
+    
+    return False
+
+def rewritehg(output):
+    if not output:
+        return output
+    # Rewrite os specific messages
+    output = output.replace(': The system cannot find the file specified',
+                            ': No such file or directory')
+    output = re.sub(': Access is denied.*$', ': Permission denied', output)
+    output = output.replace(': No connection could be made because the target machine actively refused it',
+                            ': Connection refused')
+    return output
+                            
+
+def run_command(name, args, interp, env, stdin, stdout,
+                stderr, debugflags):
+    # Execute the command
+    if 'debug-utility' in debugflags:
+        print interp.log(' '.join([name, str(args), interp['PWD']]) + '\n')
+
+    hgbin = interp.options().hgbinary
+    ishg = hgbin and ('hg' in name or args and 'hg' in args[0])
+    unixoutput = 'cygwin' in name or ishg
+    
+    exec_env = env.get_variables()        
+    try:
+        # BUG: comparing file descriptor is clearly not a reliable way to tell
+        # whether they point on the same underlying object. But in pysh limited
+        # scope this is usually right, we do not expect complicated redirections
+        # besides usual 2>&1.
+        # Still there is one case we have but cannot deal with is when stdout
+        # and stderr are redirected *by pysh caller*. This the reason for the
+        # --redirect pysh() option.
+        # Now, we want to know they are the same because we sometimes need to 
+        # transform the command output, mostly remove CR-LF to ensure that
+        # command output is unix-like. Cygwin utilies are a special case because
+        # they explicitely set their output streams to binary mode, so we have
+        # nothing to do. For all others commands, we have to guess whether they
+        # are sending text data, in which case the transformation must be done.
+        # Again, the NUL character test is unreliable but should be enough for
+        # hg tests.
+        redirected = stdout.fileno()==stderr.fileno()
+        if not redirected:
+            p = subprocess.Popen([name] + args, cwd=env['PWD'], env=exec_env, 
+                    stdin=stdin, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+        else:
+            p = subprocess.Popen([name] + args, cwd=env['PWD'], env=exec_env, 
+                    stdin=stdin, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
+        out, err = p.communicate()
+    except WindowsError, e:
+        raise UtilityError(str(e))
+
+    if not unixoutput:
+        def encode(s):
+            if '\0' in s:
+                return s
+            return s.replace('\r\n', '\n')
+    else:
+        encode = lambda s: s
+
+    if rewriteslashes(name, args):
+        encode1_ = encode
+        def encode(s):
+            s = encode1_(s)
+            s = s.replace('\\\\', '\\')
+            s = s.replace('\\', '/')
+            return s
+
+    if ishg:
+        encode2_ = encode
+        def encode(s):
+            return rewritehg(encode2_(s))
+    
+    stdout.write(encode(out))
+    if not redirected:
+        stderr.write(encode(err))
+    return p.returncode
+            
diff --git a/bitbake/lib/pysh/interp.py b/bitbake/lib/pysh/interp.py
new file mode 100644
index 0000000000..efe5181e1e
--- /dev/null
+++ b/bitbake/lib/pysh/interp.py
@@ -0,0 +1,1367 @@
+# interp.py - shell interpreter for pysh.
+#
+# Copyright 2007 Patrick Mezard
+#
+# This software may be used and distributed according to the terms
+# of the GNU General Public License, incorporated herein by reference.
+
+"""Implement the shell interpreter.
+
+Most references are made to "The Open Group Base Specifications Issue 6".
+<http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html>
+"""
+# TODO: document the fact input streams must implement fileno() so Popen will work correctly.
+# it requires non-stdin stream to be implemented as files. Still to be tested...
+# DOC: pathsep is used in PATH instead of ':'. Clearly, there are path syntax issues here.
+# TODO: stop command execution upon error.
+# TODO: sort out the filename/io_number mess. It should be possible to use filenames only.
+# TODO: review subshell implementation
+# TODO: test environment cloning for non-special builtins
+# TODO: set -x should not rebuild commands from tokens, assignments/redirections are lost
+# TODO: unit test for variable assignment
+# TODO: test error management wrt error type/utility type
+# TODO: test for binary output everywhere
+# BUG: debug-parsing does not pass log file to PLY. Maybe a PLY upgrade is necessary.
+import base64
+import cPickle as pickle
+import errno
+import glob
+import os
+import re
+import subprocess
+import sys
+import tempfile
+
+try:
+    s = set()
+    del s
+except NameError:
+    from Set import Set as set
+
+import builtin
+from sherrors import *
+import pyshlex
+import pyshyacc
+
+def mappend(func, *args, **kargs):
+    """Like map but assume func returns a list. Returned lists are merged into
+    a single one.
+    """
+    return reduce(lambda a,b: a+b, map(func, *args, **kargs), [])
+
+class FileWrapper:
+    """File object wrapper to ease debugging.
+    
+    Allow mode checking and implement file duplication through a simple 
+    reference counting scheme. Not sure the latter is really useful since
+    only real file descriptors can be used.
+    """
+    def __init__(self, mode, file, close=True):
+        if mode not in ('r', 'w', 'a'):
+            raise IOError('invalid mode: %s' % mode)
+        self._mode = mode
+        self._close = close
+        if isinstance(file, FileWrapper):
+            if file._refcount[0] <= 0:
+                raise IOError(0, 'Error')
+            self._refcount = file._refcount
+            self._refcount[0] += 1
+            self._file = file._file
+        else:
+            self._refcount = [1]
+            self._file = file
+        
+    def dup(self):
+        return FileWrapper(self._mode, self, self._close)
+        
+    def fileno(self):
+        """fileno() should be only necessary for input streams."""
+        return self._file.fileno()
+        
+    def read(self, size=-1):
+        if self._mode!='r':
+            raise IOError(0, 'Error')
+        return self._file.read(size)
+        
+    def readlines(self, *args, **kwargs):
+        return self._file.readlines(*args, **kwargs)
+        
+    def write(self, s):
+        if self._mode not in ('w', 'a'):
+            raise IOError(0, 'Error')
+        return self._file.write(s)
+        
+    def flush(self):
+        self._file.flush()
+        
+    def close(self):        
+        if not self._refcount:
+            return
+        assert  self._refcount[0] > 0
+        
+        self._refcount[0] -= 1    
+        if self._refcount[0] == 0:
+            self._mode = 'c'
+            if self._close:
+                self._file.close()
+        self._refcount = None
+                
+    def mode(self):
+        return self._mode
+
+    def __getattr__(self, name):
+        if name == 'name':
+            self.name = getattr(self._file, name)
+            return self.name
+        else:
+            raise AttributeError(name)
+
+    def __del__(self):
+        self.close()
+               
+               
+def win32_open_devnull(mode):
+    return open('NUL', mode)
+    
+        
+class Redirections:
+    """Stores open files and their mapping to pseudo-sh file descriptor.
+    """
+    # BUG: redirections are not handled correctly: 1>&3 2>&3 3>&4 does 
+    # not make 1 to redirect to 4
+    def __init__(self, stdin=None, stdout=None, stderr=None):
+        self._descriptors = {}
+        if stdin is not None:
+            self._add_descriptor(0, stdin)
+        if stdout is not None:
+            self._add_descriptor(1, stdout)
+        if stderr is not None:
+            self._add_descriptor(2, stderr)
+            
+    def add_here_document(self, interp, name, content, io_number=None):
+        if io_number is None:
+            io_number = 0
+            
+        if name==pyshlex.unquote_wordtree(name):
+            content = interp.expand_here_document(('TOKEN', content))
+    
+        # Write document content in a temporary file
+        tmp = tempfile.TemporaryFile()
+        try:
+            tmp.write(content)
+            tmp.flush()
+            tmp.seek(0)
+            self._add_descriptor(io_number, FileWrapper('r', tmp))
+        except:
+            tmp.close()
+            raise                
+        
+    def add(self, interp, op, filename, io_number=None):
+        if op not in ('<', '>', '>|', '>>', '>&'):
+            # TODO: add descriptor duplication and here_documents      
+            raise RedirectionError('Unsupported redirection operator "%s"' % op)
+            
+        if io_number is not None:
+            io_number = int(io_number)
+            
+        if (op == '>&' and filename.isdigit()) or filename=='-':
+            # No expansion for file descriptors, quote them if you want a filename
+            fullname = filename
+        else:
+            if filename.startswith('/'):
+                # TODO: win32 kludge
+                if filename=='/dev/null':
+                    fullname = 'NUL'
+                else:
+                    # TODO: handle absolute pathnames, they are unlikely to exist on the
+                    # current platform (win32 for instance).
+                    raise NotImplementedError()
+            else:
+                fullname = interp.expand_redirection(('TOKEN', filename))
+                if not fullname:
+                    raise RedirectionError('%s: ambiguous redirect' % filename)
+                # Build absolute path based on PWD
+                fullname = os.path.join(interp.get_env()['PWD'], fullname)
+            
+        if op=='<':
+            return self._add_input_redirection(interp, fullname, io_number)
+        elif op in ('>', '>|'):
+            clobber = ('>|'==op)
+            return self._add_output_redirection(interp, fullname, io_number, clobber)
+        elif op=='>>':
+            return self._add_output_appending(interp, fullname, io_number)
+        elif op=='>&':
+            return self._dup_output_descriptor(fullname, io_number)
+        
+    def close(self):
+        if self._descriptors is not None:
+            for desc in self._descriptors.itervalues():
+                desc.flush()
+                desc.close()
+            self._descriptors = None
+            
+    def stdin(self):
+        return self._descriptors[0]
+          
+    def stdout(self):
+        return self._descriptors[1] 
+        
+    def stderr(self):
+        return self._descriptors[2] 
+            
+    def clone(self):
+        clone = Redirections()
+        for desc, fileobj in self._descriptors.iteritems():
+            clone._descriptors[desc] = fileobj.dup()
+        return clone
+           
+    def _add_output_redirection(self, interp, filename, io_number, clobber):    
+        if io_number is None:
+            # io_number default to standard output
+            io_number = 1
+        
+        if not clobber and interp.get_env().has_opt('-C') and os.path.isfile(filename):
+            # File already exist in no-clobber mode, bail out
+            raise RedirectionError('File "%s" already exists' % filename)
+            
+        # Open and register
+        self._add_file_descriptor(io_number, filename, 'w')
+        
+    def _add_output_appending(self, interp, filename, io_number):    
+        if io_number is None:
+            io_number = 1
+        self._add_file_descriptor(io_number, filename, 'a')
+            
+    def _add_input_redirection(self, interp, filename, io_number):
+        if io_number is None:
+            io_number = 0
+        self._add_file_descriptor(io_number, filename, 'r')
+        
+    def _add_file_descriptor(self, io_number, filename, mode):    
+        try:            
+            if filename.startswith('/'):
+                if filename=='/dev/null':
+                    f = win32_open_devnull(mode+'b')
+                else:
+                    # TODO: handle absolute pathnames, they are unlikely to exist on the
+                    # current platform (win32 for instance).
+                    raise NotImplementedError('cannot open absolute path %s' % repr(filename))
+            else:
+                f = file(filename, mode+'b')
+        except IOError, e:
+            raise RedirectionError(str(e))
+            
+        wrapper = None
+        try:
+            wrapper = FileWrapper(mode, f)
+            f = None
+            self._add_descriptor(io_number, wrapper)
+        except:
+            if f: f.close()
+            if wrapper: wrapper.close()
+            raise
+            
+    def _dup_output_descriptor(self, source_fd, dest_fd):
+        if source_fd is None:
+            source_fd = 1
+        self._dup_file_descriptor(source_fd, dest_fd, 'w')
+            
+    def _dup_file_descriptor(self, source_fd, dest_fd, mode):
+        source_fd = int(source_fd)
+        if source_fd not in self._descriptors:
+            raise RedirectionError('"%s" is not a valid file descriptor' % str(source_fd))
+        source = self._descriptors[source_fd]
+        
+        if source.mode()!=mode:
+            raise RedirectionError('Descriptor %s cannot be duplicated in mode "%s"' % (str(source), mode))
+        
+        if dest_fd=='-':
+            # Close the source descriptor
+            del self._descriptors[source_fd]
+            source.close()
+        else:
+            dest_fd = int(dest_fd)
+            if dest_fd not in self._descriptors:
+                raise RedirectionError('Cannot replace file descriptor %s' % str(dest_fd))
+                
+            dest = self._descriptors[dest_fd]
+            if dest.mode()!=mode:
+                raise RedirectionError('Descriptor %s cannot be cannot be redirected in mode "%s"' % (str(dest), mode))
+            
+            self._descriptors[dest_fd] = source.dup()
+            dest.close()        
+            
+    def _add_descriptor(self, io_number, file):
+        io_number = int(io_number)
+        
+        if io_number in self._descriptors:
+            # Close the current descriptor
+            d = self._descriptors[io_number]
+            del self._descriptors[io_number]
+            d.close()
+            
+        self._descriptors[io_number] = file
+
+    def __str__(self):
+        names = [('%d=%r' % (k, getattr(v, 'name', None))) for k,v
+                 in self._descriptors.iteritems()]
+        names = ','.join(names)
+        return 'Redirections(%s)' % names
+
+    def __del__(self):
+        self.close()
+    
+def cygwin_to_windows_path(path):
+    """Turn /cygdrive/c/foo into c:/foo, or return path if it
+    is not a cygwin path.
+    """
+    if not path.startswith('/cygdrive/'):
+        return path
+    path = path[len('/cygdrive/'):]
+    path = path[:1] + ':' + path[1:]
+    return path
+    
+def win32_to_unix_path(path):
+    if path is not None:
+        path = path.replace('\\', '/')
+    return path    
+    
+_RE_SHEBANG = re.compile(r'^\#!\s?([^\s]+)(?:\s([^\s]+))?')
+_SHEBANG_CMDS = {
+    '/usr/bin/env': 'env',
+    '/bin/sh': 'pysh',
+    'python': 'python',
+}
+    
+def resolve_shebang(path, ignoreshell=False):
+    """Return a list of arguments as shebang interpreter call or an empty list
+    if path does not refer to an executable script.
+    See <http://www.opengroup.org/austin/docs/austin_51r2.txt>.
+    
+    ignoreshell - set to True to ignore sh shebangs. Return an empty list instead.
+    """
+    try:
+        f = file(path)
+        try:
+            # At most 80 characters in the first line
+            header = f.read(80).splitlines()[0]
+        finally:
+            f.close()
+            
+        m = _RE_SHEBANG.search(header)
+        if not m:
+            return []
+        cmd, arg = m.group(1,2)
+        if os.path.isfile(cmd):
+            # Keep this one, the hg script for instance contains a weird windows
+            # shebang referencing the current python install.
+            cmdfile = os.path.basename(cmd).lower()
+            if cmdfile == 'python.exe':
+                cmd = 'python'
+            pass
+        elif cmd not in _SHEBANG_CMDS:
+            raise CommandNotFound('Unknown interpreter "%s" referenced in '\
+                'shebang' % header)
+        cmd = _SHEBANG_CMDS.get(cmd)
+        if cmd is None or (ignoreshell and cmd == 'pysh'):
+            return []
+        if arg is None:
+            return [cmd, win32_to_unix_path(path)]
+        return [cmd, arg, win32_to_unix_path(path)]
+    except IOError, e:
+        if  e.errno!=errno.ENOENT and \
+            (e.errno!=errno.EPERM and not os.path.isdir(path)): # Opening a directory raises EPERM
+            raise
+        return []
+        
+def win32_find_in_path(name, path):
+    if isinstance(path, str):
+        path = path.split(os.pathsep)
+        
+    exts = os.environ.get('PATHEXT', '').lower().split(os.pathsep)
+    for p in path:
+        p_name = os.path.join(p, name)
+        
+        prefix = resolve_shebang(p_name)
+        if prefix:
+            return prefix
+            
+        for ext in exts:    
+            p_name_ext = p_name + ext
+            if os.path.exists(p_name_ext):
+                return [win32_to_unix_path(p_name_ext)]
+    return []
+
+class Traps(dict):
+    def __setitem__(self, key, value):
+        if key not in ('EXIT',):
+            raise NotImplementedError()
+        super(Traps, self).__setitem__(key, value)
+
+# IFS white spaces character class
+_IFS_WHITESPACES = (' ', '\t', '\n')
+
+class Environment:
+    """Environment holds environment variables, export table, function 
+    definitions and whatever is defined in 2.12 "Shell Execution Environment",
+    redirection excepted.
+    """
+    def __init__(self, pwd):
+        self._opt = set()       #Shell options
+        
+        self._functions = {}        
+        self._env = {'?': '0', '#': '0'}
+        self._exported = set([
+            'HOME', 'IFS', 'PATH'
+        ])
+        
+        # Set environment vars with side-effects
+        self._ifs_ws = None     # Set of IFS whitespace characters
+        self._ifs_re = None     # Regular expression used to split between words using IFS classes
+        self['IFS'] = ''.join(_IFS_WHITESPACES) #Default environment values
+        self['PWD'] = pwd
+        self.traps = Traps()
+        
+    def clone(self, subshell=False):
+        env = Environment(self['PWD'])
+        env._opt = set(self._opt)
+        for k,v in self.get_variables().iteritems():
+            if k in self._exported:
+                env.export(k,v)
+            elif subshell:
+                env[k] = v
+                
+        if subshell:
+            env._functions = dict(self._functions)
+            
+        return env        
+        
+    def __getitem__(self, key):
+        if key in ('@', '*', '-', '$'):
+            raise NotImplementedError('%s is not implemented' % repr(key))
+        return self._env[key]
+        
+    def get(self, key, defval=None):
+        try:
+            return self[key]
+        except KeyError:
+            return defval
+        
+    def __setitem__(self, key, value):
+        if key=='IFS':
+            # Update the whitespace/non-whitespace classes
+            self._update_ifs(value)
+        elif key=='PWD':
+            pwd = os.path.abspath(value)
+            if not os.path.isdir(pwd):
+                raise VarAssignmentError('Invalid directory %s' % value)
+            value = pwd
+        elif key in ('?', '!'):
+            value = str(int(value))
+        self._env[key] = value
+        
+    def __delitem__(self, key):
+        if key in ('IFS', 'PWD', '?'):
+            raise VarAssignmentError('%s cannot be unset' % key)
+        del self._env[key]
+
+    def __contains__(self, item):
+        return item in self._env
+        
+    def set_positional_args(self, args):
+        """Set the content of 'args' as positional argument from 1 to len(args).
+        Return previous argument as a list of strings.
+        """
+        # Save and remove previous arguments
+        prevargs = []        
+        for i in xrange(int(self._env['#'])):
+            i = str(i+1)
+            prevargs.append(self._env[i])
+            del self._env[i]
+        self._env['#'] = '0'
+                
+        #Set new ones
+        for i,arg in enumerate(args):
+            self._env[str(i+1)] = str(arg)
+        self._env['#'] = str(len(args))
+        
+        return prevargs
+        
+    def get_positional_args(self):
+        return [self._env[str(i+1)] for i in xrange(int(self._env['#']))]
+        
+    def get_variables(self):
+        return dict(self._env)
+        
+    def export(self, key, value=None):
+        if value is not None:
+            self[key] = value
+        self._exported.add(key)
+        
+    def get_exported(self):
+        return [(k,self._env.get(k)) for k in self._exported]
+            
+    def split_fields(self, word):
+        if not self._ifs_ws or not word:
+            return [word]
+        return re.split(self._ifs_re, word)
+   
+    def _update_ifs(self, value):
+        """Update the split_fields related variables when IFS character set is
+        changed.
+        """
+        # TODO: handle NULL IFS
+        
+        # Separate characters in whitespace and non-whitespace
+        chars = set(value)
+        ws = [c for c in chars if c in _IFS_WHITESPACES]
+        nws = [c for c in chars if c not in _IFS_WHITESPACES]
+        
+        # Keep whitespaces in a string for left and right stripping
+        self._ifs_ws = ''.join(ws)
+        
+        # Build a regexp to split fields
+        trailing = '[' + ''.join([re.escape(c) for c in ws]) + ']'
+        if nws:
+            # First, the single non-whitespace occurence.
+            nws = '[' + ''.join([re.escape(c) for c in nws]) + ']'
+            nws = '(?:' + trailing + '*' + nws + trailing + '*' + '|' + trailing + '+)'
+        else:
+            # Then mix all parts with quantifiers
+            nws = trailing + '+'
+        self._ifs_re = re.compile(nws)
+       
+    def has_opt(self, opt, val=None):
+        return (opt, val) in self._opt
+        
+    def set_opt(self, opt, val=None):
+        self._opt.add((opt, val))
+        
+    def find_in_path(self, name, pwd=False):
+        path = self._env.get('PATH', '').split(os.pathsep)
+        if pwd:
+            path[:0] = [self['PWD']]
+        if os.name == 'nt':
+            return win32_find_in_path(name, self._env.get('PATH', ''))
+        else:
+            raise NotImplementedError()
+            
+    def define_function(self, name, body):
+        if not is_name(name):
+            raise ShellSyntaxError('%s is not a valid function name' % repr(name))
+        self._functions[name] = body
+        
+    def remove_function(self, name):
+        del self._functions[name]
+        
+    def is_function(self, name):
+        return name in self._functions
+        
+    def get_function(self, name):
+        return self._functions.get(name)
+        
+       
+name_charset = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_'
+name_charset = dict(zip(name_charset,name_charset))
+           
+def match_name(s):
+    """Return the length in characters of the longest prefix made of name
+    allowed characters in s.
+    """
+    for i,c in enumerate(s):
+        if c not in name_charset:
+            return s[:i]
+    return s
+    
+def is_name(s):
+    return len([c for c in s if c not in name_charset])<=0
+    
+def is_special_param(c):
+    return len(c)==1 and c in ('@','*','#','?','-','$','!','0')
+    
+def utility_not_implemented(name, *args, **kwargs):
+    raise NotImplementedError('%s utility is not implemented' % name)
+    
+
+class Utility:
+    """Define utilities properties:
+    func -- utility callable. See builtin module for utility samples.
+    is_special -- see XCU 2.8.
+    """
+    def __init__(self, func, is_special=0):
+        self.func = func
+        self.is_special = bool(is_special)
+
+
+def encodeargs(args):
+    def encodearg(s):
+        lines = base64.encodestring(s)
+        lines = [l.splitlines()[0] for l in lines]
+        return ''.join(lines)
+
+    s = pickle.dumps(args)
+    return encodearg(s)
+
+def decodeargs(s):
+    s = base64.decodestring(s)
+    return pickle.loads(s)
+    
+
+class GlobError(Exception):
+    pass
+
+class Options:
+    def __init__(self):
+        # True if Mercurial operates with binary streams
+        self.hgbinary = True
+
+class Interpreter:
+    # Implementation is very basic: the execute() method just makes a DFS on the
+    # AST and execute nodes one by one. Nodes are tuple (name,obj) where name
+    # is a string identifier and obj the AST element returned by the parser.
+    #
+    # Handler are named after the node identifiers.
+    # TODO: check node names and remove the switch in execute with some
+    # dynamic getattr() call to find node handlers.
+    """Shell interpreter.
+    
+    The following debugging flags can be passed:
+    debug-parsing - enable PLY debugging.
+    debug-tree - print the generated AST.
+    debug-cmd - trace command execution before word expansion, plus exit status.
+    debug-utility - trace utility execution.
+    """
+    
+    # List supported commands.
+    COMMANDS = {
+        'cat':       Utility(builtin.utility_cat,),
+        'cd':       Utility(builtin.utility_cd,),
+        ':':        Utility(builtin.utility_colon,),
+        'echo':     Utility(builtin.utility_echo),
+        'env':      Utility(builtin.utility_env),
+        'exit':     Utility(builtin.utility_exit),
+        'export':   Utility(builtin.builtin_export,     is_special=1),
+        'egrep':    Utility(builtin.utility_egrep),
+        'fgrep':    Utility(builtin.utility_fgrep),
+        'gunzip':   Utility(builtin.utility_gunzip),
+        'kill':     Utility(builtin.utility_kill),
+        'mkdir':    Utility(builtin.utility_mkdir),
+        'netstat':  Utility(builtin.utility_netstat),
+        'printf':   Utility(builtin.utility_printf),
+        'pwd':      Utility(builtin.utility_pwd),
+        'return':   Utility(builtin.builtin_return,     is_special=1),
+        'sed':      Utility(builtin.utility_sed,),
+        'set':      Utility(builtin.builtin_set,),
+        'shift':    Utility(builtin.builtin_shift,),
+        'sleep':    Utility(builtin.utility_sleep,),
+        'sort':     Utility(builtin.utility_sort,),
+        'trap':     Utility(builtin.builtin_trap,       is_special=1),
+        'true':     Utility(builtin.utility_true),
+        'unset':    Utility(builtin.builtin_unset,      is_special=1),
+        'wait':     Utility(builtin.builtin_wait,       is_special=1),
+    }
+    
+    def __init__(self, pwd, debugflags = [], env=None, redirs=None, stdin=None,
+                 stdout=None, stderr=None, opts=Options()):
+        self._env = env
+        if self._env is None:
+            self._env = Environment(pwd)
+        self._children = {}
+            
+        self._redirs = redirs
+        self._close_redirs = False
+        
+        if self._redirs is None:
+            if stdin is None:
+                stdin = sys.stdin
+            if stdout is None:
+                stdout = sys.stdout
+            if stderr is None:
+                stderr = sys.stderr
+            stdin = FileWrapper('r', stdin, False)
+            stdout = FileWrapper('w', stdout, False)
+            stderr = FileWrapper('w', stderr, False)
+            self._redirs = Redirections(stdin, stdout, stderr)
+            self._close_redirs = True
+            
+        self._debugflags = list(debugflags)
+        self._logfile = sys.stderr
+        self._options = opts
+        
+    def close(self):
+        """Must be called when the interpreter is no longer used."""
+        script = self._env.traps.get('EXIT')
+        if script:
+            try:
+                self.execute_script(script=script)
+            except:
+                pass
+
+        if self._redirs is not None and self._close_redirs:
+            self._redirs.close()
+            self._redirs = None
+            
+    def log(self, s):
+        self._logfile.write(s)
+        self._logfile.flush()
+            
+    def __getitem__(self, key):
+        return self._env[key]
+        
+    def __setitem__(self, key, value):
+        self._env[key] = value
+
+    def options(self):
+        return self._options
+
+    def redirect(self, redirs, ios):
+        def add_redir(io):
+            if isinstance(io, pyshyacc.IORedirect):
+                redirs.add(self, io.op, io.filename, io.io_number)
+            else:
+                redirs.add_here_document(self, io.name, io.content, io.io_number)
+                    
+        map(add_redir, ios)
+        return redirs
+            
+    def execute_script(self, script=None, ast=None, sourced=False,
+                       scriptpath=None):
+        """If script is not None, parse the input. Otherwise takes the supplied
+        AST. Then execute the AST.
+        Return the script exit status.
+        """
+        try:
+            if scriptpath is not None:
+                self._env['0'] = os.path.abspath(scriptpath)
+
+            if script is not None:
+                debug_parsing = ('debug-parsing' in self._debugflags)    
+                cmds, script = pyshyacc.parse(script, True, debug_parsing)
+                if 'debug-tree' in self._debugflags:
+                    pyshyacc.print_commands(cmds, self._logfile)
+                    self._logfile.flush()
+            else:
+                cmds, script = ast, ''                
+                
+            status = 0
+            for cmd in cmds:
+                try:
+                    status = self.execute(cmd)
+                except ExitSignal, e:
+                    if sourced:
+                        raise
+                    status = int(e.args[0])
+                    return status
+                except ShellError:
+                    self._env['?'] = 1
+                    raise
+                if 'debug-utility' in self._debugflags or 'debug-cmd' in self._debugflags:
+                    self.log('returncode ' + str(status)+ '\n')
+            return status
+        except CommandNotFound, e:
+            print >>self._redirs.stderr, str(e)
+            self._redirs.stderr.flush()
+            # Command not found by non-interactive shell
+            # return 127
+            raise
+        except RedirectionError, e:
+            # TODO: should be handled depending on the utility status
+            print >>self._redirs.stderr, str(e)
+            self._redirs.stderr.flush()
+            # Command not found by non-interactive shell
+            # return 127
+            raise
+
+    def dotcommand(self, env, args):
+        if len(args) < 1:
+            raise ShellError('. expects at least one argument')
+        path = args[0]
+        if '/' not in path:
+            found = env.find_in_path(args[0], True)
+            if found:
+                path = found[0]
+        script = file(path).read()
+        return self.execute_script(script=script, sourced=True)
+
+    def execute(self, token, redirs=None):
+        """Execute and AST subtree with supplied redirections overriding default
+        interpreter ones.
+        Return the exit status.
+        """
+        if not token:
+            return 0
+            
+        if redirs is None:
+            redirs = self._redirs
+            
+        if isinstance(token, list):
+            # Commands sequence
+            res = 0
+            for t in token:
+                res = self.execute(t, redirs)
+            return res
+
+        type, value = token
+        status = 0
+        if type=='simple_command':
+            redirs_copy = redirs.clone()
+            try:
+                # TODO: define and handle command return values
+                # TODO: implement set -e
+                status = self._execute_simple_command(value, redirs_copy)
+            finally:
+                redirs_copy.close()
+        elif type=='pipeline':
+            status = self._execute_pipeline(value, redirs)
+        elif type=='and_or':
+            status = self._execute_and_or(value, redirs)
+        elif type=='for_clause':
+            status = self._execute_for_clause(value, redirs)
+        elif type=='while_clause':
+            status = self._execute_while_clause(value, redirs)
+        elif type=='function_definition':
+            status = self._execute_function_definition(value, redirs)
+        elif type=='brace_group':
+            status = self._execute_brace_group(value, redirs)
+        elif type=='if_clause':
+            status = self._execute_if_clause(value, redirs)
+        elif type=='subshell':
+            status = self.subshell(ast=value.cmds, redirs=redirs)
+        elif type=='async':
+            status = self._asynclist(value)
+        elif type=='redirect_list':
+            redirs_copy = self.redirect(redirs.clone(), value.redirs)
+            try:
+                status = self.execute(value.cmd, redirs_copy)
+            finally:
+                redirs_copy.close()
+        else:
+            raise NotImplementedError('Unsupported token type ' + type)
+
+        if status < 0:
+            status = 255
+        return status
+            
+    def _execute_if_clause(self, if_clause, redirs):
+        cond_status = self.execute(if_clause.cond, redirs)
+        if cond_status==0:
+            return self.execute(if_clause.if_cmds, redirs)
+        else:
+            return self.execute(if_clause.else_cmds, redirs)
+      
+    def _execute_brace_group(self, group, redirs):
+        status = 0
+        for cmd in group.cmds:
+            status = self.execute(cmd, redirs)
+        return status
+            
+    def _execute_function_definition(self, fundef, redirs):
+        self._env.define_function(fundef.name, fundef.body)
+        return 0
+            
+    def _execute_while_clause(self, while_clause, redirs):
+        status = 0
+        while 1:
+            cond_status = 0
+            for cond in while_clause.condition:
+                cond_status = self.execute(cond, redirs)
+                
+            if cond_status:
+                break
+                
+            for cmd in while_clause.cmds:
+                status = self.execute(cmd, redirs)
+                
+        return status
+            
+    def _execute_for_clause(self, for_clause, redirs):
+        if not is_name(for_clause.name):
+            raise ShellSyntaxError('%s is not a valid name' % repr(for_clause.name))
+        items = mappend(self.expand_token, for_clause.items)
+        
+        status = 0    
+        for item in items:
+            self._env[for_clause.name] = item
+            for cmd in for_clause.cmds:
+                status = self.execute(cmd, redirs)
+        return status
+            
+    def _execute_and_or(self, or_and, redirs):
+        res = self.execute(or_and.left, redirs)        
+        if (or_and.op=='&&' and res==0) or (or_and.op!='&&' and res!=0):
+            res = self.execute(or_and.right, redirs)
+        return res
+            
+    def _execute_pipeline(self, pipeline, redirs):            
+        if len(pipeline.commands)==1:
+            status = self.execute(pipeline.commands[0], redirs)
+        else:
+            # Execute all commands one after the other
+            status = 0
+            inpath, outpath = None, None
+            try:
+                # Commands inputs and outputs cannot really be plugged as done
+                # by a real shell. Run commands sequentially and chain their
+                # input/output throught temporary files.
+                tmpfd, inpath = tempfile.mkstemp()
+                os.close(tmpfd)
+                tmpfd, outpath = tempfile.mkstemp()
+                os.close(tmpfd)
+                
+                inpath = win32_to_unix_path(inpath)
+                outpath = win32_to_unix_path(outpath)
+                
+                for i, cmd in enumerate(pipeline.commands):
+                    call_redirs = redirs.clone()
+                    try:
+                        if i!=0:
+                            call_redirs.add(self, '<', inpath)
+                        if i!=len(pipeline.commands)-1:
+                            call_redirs.add(self, '>', outpath)
+                        
+                        status = self.execute(cmd, call_redirs)
+                        
+                        # Chain inputs/outputs
+                        inpath, outpath = outpath, inpath
+                    finally:
+                        call_redirs.close()            
+            finally:
+                if inpath: os.remove(inpath)
+                if outpath: os.remove(outpath)
+        
+        if pipeline.reverse_status:
+            status = int(not status)
+        self._env['?'] = status
+        return status
+        
+    def _execute_function(self, name, args, interp, env, stdin, stdout, stderr, *others):
+        assert interp is self
+        
+        func = env.get_function(name)
+        #Set positional parameters
+        prevargs = None
+        try:
+            prevargs = env.set_positional_args(args)
+            try:
+                redirs = Redirections(stdin.dup(), stdout.dup(), stderr.dup())
+                try:
+                    status = self.execute(func, redirs)
+                finally:
+                    redirs.close()
+            except ReturnSignal, e:
+                status = int(e.args[0])
+                env['?'] = status
+            return status
+        finally:
+            #Reset positional parameters
+            if prevargs is not None:
+                env.set_positional_args(prevargs)
+                
+    def _execute_simple_command(self, token, redirs):
+        """Can raise ReturnSignal when return builtin is called, ExitSignal when
+        exit is called, and other shell exceptions upon builtin failures.
+        """
+        debug_command = 'debug-cmd' in self._debugflags
+        if debug_command:
+            self.log('word' + repr(token.words) + '\n')
+            self.log('assigns' + repr(token.assigns) + '\n')
+            self.log('redirs' + repr(token.redirs) + '\n')
+        
+        is_special = None
+        env = self._env
+        
+        try:
+            # Word expansion
+            args = []
+            for word in token.words:                
+                args += self.expand_token(word)
+                if is_special is None and args:
+                    is_special = env.is_function(args[0]) or \
+                        (args[0] in self.COMMANDS and self.COMMANDS[args[0]].is_special)
+                        
+            if debug_command:
+                self.log('_execute_simple_command' + str(args) + '\n')
+                
+            if not args:
+                # Redirections happen is a subshell
+                redirs = redirs.clone()
+            elif not is_special:
+                env = self._env.clone()
+            
+            # Redirections
+            self.redirect(redirs, token.redirs)
+                
+            # Variables assignments
+            res = 0
+            for type,(k,v) in token.assigns:
+                status, expanded = self.expand_variable((k,v))
+                if status is not None:
+                    res = status
+                if args:
+                    env.export(k, expanded)
+                else:
+                    env[k] = expanded
+                
+            if args and args[0] in ('.', 'source'):
+                res = self.dotcommand(env, args[1:])
+            elif args:
+                if args[0] in self.COMMANDS:
+                    command = self.COMMANDS[args[0]]
+                elif env.is_function(args[0]):
+                    command = Utility(self._execute_function, is_special=True)
+                else:
+                    if not '/' in args[0].replace('\\', '/'):
+                        cmd = env.find_in_path(args[0])
+                        if not cmd:
+                            # TODO: test error code on unknown command => 127
+                            raise CommandNotFound('Unknown command: "%s"' % args[0])
+                    else:
+                        # Handle commands like '/cygdrive/c/foo.bat'
+                        cmd = cygwin_to_windows_path(args[0])
+                        if not os.path.exists(cmd):
+                            raise CommandNotFound('%s: No such file or directory' % args[0])
+                        shebang = resolve_shebang(cmd)
+                        if shebang:
+                            cmd = shebang
+                        else:
+                            cmd = [cmd]
+                    args[0:1] = cmd
+                    command = Utility(builtin.run_command)
+                
+                # Command execution
+                if 'debug-cmd' in self._debugflags:
+                    self.log('redirections ' + str(redirs) + '\n')
+                    
+                res = command.func(args[0], args[1:], self, env,
+                                   redirs.stdin(), redirs.stdout(), 
+                                   redirs.stderr(), self._debugflags)
+            
+            if self._env.has_opt('-x'):
+                # Trace command execution in shell environment
+                # BUG: would be hard to reproduce a real shell behaviour since
+                # the AST is not annotated with source lines/tokens.
+                self._redirs.stdout().write(' '.join(args))
+                
+        except ReturnSignal:
+            raise
+        except ShellError, e:
+            if is_special or isinstance(e, (ExitSignal,
+                                            ShellSyntaxError, ExpansionError)):
+                raise e
+            self._redirs.stderr().write(str(e)+'\n')
+            return 1
+
+        return res
+
+    def expand_token(self, word):
+        """Expand a word as specified in [2.6 Word Expansions]. Return the list
+        of expanded words.
+        """
+        status, wtrees = self._expand_word(word)
+        return map(pyshlex.wordtree_as_string, wtrees)
+        
+    def expand_variable(self, word):
+        """Return a status code (or None if no command expansion occurred)
+        and a single word.
+        """
+        status, wtrees = self._expand_word(word, pathname=False, split=False)
+        words = map(pyshlex.wordtree_as_string, wtrees)
+        assert len(words)==1
+        return status, words[0]
+        
+    def expand_here_document(self, word):
+        """Return the expanded document as a single word. The here document is 
+        assumed to be unquoted.
+        """
+        status, wtrees = self._expand_word(word, pathname=False,
+                                           split=False, here_document=True)
+        words = map(pyshlex.wordtree_as_string, wtrees)
+        assert len(words)==1
+        return words[0]
+        
+    def expand_redirection(self, word):
+        """Return a single word."""
+        return self.expand_variable(word)[1]
+        
+    def get_env(self):
+        return self._env
+        
+    def _expand_word(self, token, pathname=True, split=True, here_document=False):
+        wtree = pyshlex.make_wordtree(token[1], here_document=here_document)
+        
+        # TODO: implement tilde expansion
+        def expand(wtree):
+            """Return a pseudo wordtree: the tree or its subelements can be empty
+            lists when no value result from the expansion.
+            """
+            status = None
+            for part in wtree:
+                if not isinstance(part, list):
+                    continue
+                if part[0]in ("'", '\\'):
+                    continue
+                elif part[0] in ('`', '$('):
+                    status, result = self._expand_command(part)
+                    part[:] = result
+                elif part[0] in ('$', '${'):
+                    part[:] = self._expand_parameter(part, wtree[0]=='"', split)
+                elif part[0] in ('', '"'):
+                    status, result = expand(part)
+                    part[:] = result
+                else:
+                    raise NotImplementedError('%s expansion is not implemented'
+                                              % part[0])
+            # [] is returned when an expansion result in no-field,
+            # like an empty $@
+            wtree = [p for p in wtree if p != []]
+            if len(wtree) < 3:
+                return status, []
+            return status, wtree
+        
+        status, wtree = expand(wtree)
+        if len(wtree) == 0:
+            return status, wtree
+        wtree = pyshlex.normalize_wordtree(wtree)
+        
+        if split:
+            wtrees = self._split_fields(wtree)
+        else:
+            wtrees = [wtree]
+        
+        if pathname:
+            wtrees = mappend(self._expand_pathname, wtrees)
+        
+        wtrees = map(self._remove_quotes, wtrees)
+        return status, wtrees
+        
+    def _expand_command(self, wtree):
+        # BUG: there is something to do with backslashes and quoted
+        # characters here
+        command = pyshlex.wordtree_as_string(wtree[1:-1])
+        status, output = self.subshell_output(command)
+        return status, ['', output, '']
+        
+    def _expand_parameter(self, wtree, quoted=False, split=False):
+        """Return a valid wtree or an empty list when no parameter results."""
+        # Get the parameter name
+        # TODO: implement weird expansion rules with ':'
+        name = pyshlex.wordtree_as_string(wtree[1:-1])
+        if not is_name(name) and not is_special_param(name):
+            raise ExpansionError('Bad substitution "%s"' % name)
+        # TODO: implement special parameters
+        if name in ('@', '*'):
+            args = self._env.get_positional_args()
+            if len(args) == 0:
+                return []
+            if len(args)<2:
+                return ['', ''.join(args), '']
+                
+            sep = self._env.get('IFS', '')[:1]
+            if split and quoted and name=='@':
+                # Introduce a new token to tell the caller that these parameters
+                # cause a split as specified in 2.5.2
+                return ['@'] + args + ['']
+            else:
+                return ['', sep.join(args), '']                
+        
+        return ['', self._env.get(name, ''), '']
+        
+    def _split_fields(self, wtree):
+        def is_empty(split):
+            return split==['', '', '']
+            
+        def split_positional(quoted):
+            # Return a list of wtree split according positional parameters rules.
+            # All remaining '@' groups are removed.
+            assert quoted[0]=='"'
+            
+            splits = [[]]
+            for part in quoted:
+                if not isinstance(part, list) or part[0]!='@':
+                    splits[-1].append(part)
+                else:
+                    # Empty or single argument list were dealt with already
+                    assert len(part)>3
+                    # First argument must join with the beginning part of the original word
+                    splits[-1].append(part[1])
+                    # Create double-quotes expressions for every argument after the first
+                    for arg in part[2:-1]:
+                        splits[-1].append('"')
+                        splits.append(['"', arg])
+            return splits
+        
+        # At this point, all expansions but pathnames have occured. Only quoted
+        # and positional sequences remain. Thus, all candidates for field splitting 
+        # are in the tree root, or are positional splits ('@') and lie in root
+        # children.
+        if not wtree or wtree[0] not in ('', '"'):
+            # The whole token is quoted or empty, nothing to split
+            return [wtree]
+            
+        if wtree[0]=='"':
+            wtree = ['', wtree, '']
+        
+        result = [['', '']]
+        for part in wtree[1:-1]:
+            if isinstance(part, list):
+                if part[0]=='"':
+                    splits = split_positional(part)
+                    if len(splits)<=1:
+                        result[-1] += [part, '']
+                    else:
+                        # Terminate the current split
+                        result[-1] += [splits[0], '']
+                        result += splits[1:-1]
+                        # Create a new split
+                        result += [['', splits[-1], '']]
+                else:
+                    result[-1] += [part, '']
+            else:
+                splits = self._env.split_fields(part)
+                if len(splits)<=1:
+                    # No split
+                    result[-1][-1] += part
+                else:
+                    # Terminate the current resulting part and create a new one
+                    result[-1][-1] += splits[0]
+                    result[-1].append('')
+                    result += [['', r, ''] for r in splits[1:-1]]
+                    result += [['', splits[-1]]]
+        result[-1].append('')
+        
+        # Leading and trailing empty groups come from leading/trailing blanks
+        if result and is_empty(result[-1]):
+            result[-1:] = []
+        if result and is_empty(result[0]):
+            result[:1] = []
+        return result
+        
+    def _expand_pathname(self, wtree):
+        """See [2.6.6 Pathname Expansion]."""
+        if self._env.has_opt('-f'):
+            return [wtree]
+        
+        # All expansions have been performed, only quoted sequences should remain
+        # in the tree. Generate the pattern by folding the tree, escaping special
+        # characters when appear quoted
+        special_chars = '*?[]'
+        
+        def make_pattern(wtree):
+            subpattern = []
+            for part in wtree[1:-1]:
+                if isinstance(part, list):
+                    part = make_pattern(part)
+                elif wtree[0]!='':
+                    for c in part:
+                        # Meta-characters cannot be quoted
+                        if c in special_chars:
+                            raise GlobError()
+                subpattern.append(part)
+            return ''.join(subpattern)
+            
+        def pwd_glob(pattern):
+            cwd = os.getcwd()
+            os.chdir(self._env['PWD'])
+            try:
+                return glob.glob(pattern) 
+            finally:
+                os.chdir(cwd)    
+            
+        #TODO: check working directory issues here wrt relative patterns
+        try:
+            pattern = make_pattern(wtree)
+            paths = pwd_glob(pattern)
+        except GlobError:
+            # BUG: Meta-characters were found in quoted sequences. The should 
+            # have been used literally but this is unsupported in current glob module.
+            # Instead we consider the whole tree must be used literally and
+            # therefore there is no point in globbing. This is wrong when meta
+            # characters are mixed with quoted meta in the same pattern like:
+            # < foo*"py*" >
+            paths = []
+            
+        if not paths:
+            return [wtree]
+        return [['', path, ''] for path in paths]
+        
+    def _remove_quotes(self, wtree):
+        """See [2.6.7 Quote Removal]."""
+        
+        def unquote(wtree):
+            unquoted = []
+            for part in wtree[1:-1]:
+                if isinstance(part, list):
+                    part = unquote(part)
+                unquoted.append(part)
+            return ''.join(unquoted)
+            
+        return ['', unquote(wtree), '']
+        
+    def subshell(self, script=None, ast=None, redirs=None):
+        """Execute the script or AST in a subshell, with inherited redirections
+        if redirs is not None.
+        """
+        if redirs:
+            sub_redirs = redirs
+        else:
+            sub_redirs = redirs.clone()
+        
+        subshell = None    
+        try:
+            subshell = Interpreter(None, self._debugflags, self._env.clone(True),
+                                   sub_redirs, opts=self._options)
+            return subshell.execute_script(script, ast)
+        finally:
+            if not redirs: sub_redirs.close()
+            if subshell: subshell.close()
+        
+    def subshell_output(self, script):
+        """Execute the script in a subshell and return the captured output."""        
+        # Create temporary file to capture subshell output
+        tmpfd, tmppath = tempfile.mkstemp()
+        try:
+            tmpfile = os.fdopen(tmpfd, 'wb')
+            stdout = FileWrapper('w', tmpfile)
+            
+            redirs = Redirections(self._redirs.stdin().dup(),
+                                  stdout,
+                                  self._redirs.stderr().dup())            
+            try:
+                status = self.subshell(script=script, redirs=redirs)
+            finally:
+                redirs.close()
+                redirs = None
+            
+            # Extract subshell standard output
+            tmpfile = open(tmppath, 'rb')
+            try:
+                output = tmpfile.read()
+                return status, output.rstrip('\n')
+            finally:
+                tmpfile.close()
+        finally:
+            os.remove(tmppath)
+
+    def _asynclist(self, cmd):
+        args = (self._env.get_variables(), cmd)
+        arg = encodeargs(args)
+        assert len(args) < 30*1024
+        cmd = ['pysh.bat', '--ast', '-c', arg]
+        p = subprocess.Popen(cmd, cwd=self._env['PWD'])
+        self._children[p.pid] = p
+        self._env['!'] = p.pid
+        return 0
+
+    def wait(self, pids=None):
+        if not pids:
+            pids = self._children.keys()
+
+        status = 127
+        for pid in pids:
+            if pid not in self._children:
+                continue
+            p = self._children.pop(pid)
+            status = p.wait()
+
+        return status
+
diff --git a/bitbake/lib/pysh/lsprof.py b/bitbake/lib/pysh/lsprof.py
new file mode 100644
index 0000000000..b1831c22a7
--- /dev/null
+++ b/bitbake/lib/pysh/lsprof.py
@@ -0,0 +1,116 @@
+#! /usr/bin/env python
+
+import sys
+from _lsprof import Profiler, profiler_entry
+
+__all__ = ['profile', 'Stats']
+
+def profile(f, *args, **kwds):
+    """XXX docstring"""
+    p = Profiler()
+    p.enable(subcalls=True, builtins=True)
+    try:
+        f(*args, **kwds)
+    finally:
+        p.disable()
+    return Stats(p.getstats())
+
+
+class Stats(object):
+    """XXX docstring"""
+
+    def __init__(self, data):
+        self.data = data
+
+    def sort(self, crit="inlinetime"):
+        """XXX docstring"""
+        if crit not in profiler_entry.__dict__:
+            raise ValueError("Can't sort by %s" % crit)
+        self.data.sort(lambda b, a: cmp(getattr(a, crit),
+                                        getattr(b, crit)))
+        for e in self.data:
+            if e.calls:
+                e.calls.sort(lambda b, a: cmp(getattr(a, crit),
+                                              getattr(b, crit)))
+
+    def pprint(self, top=None, file=None, limit=None, climit=None):
+        """XXX docstring"""
+        if file is None:
+            file = sys.stdout
+        d = self.data
+        if top is not None:
+            d = d[:top]
+        cols = "% 12s %12s %11.4f %11.4f   %s\n"
+        hcols = "% 12s %12s %12s %12s %s\n"
+        cols2 = "+%12s %12s %11.4f %11.4f +  %s\n"
+        file.write(hcols % ("CallCount", "Recursive", "Total(ms)",
+                            "Inline(ms)", "module:lineno(function)"))
+        count = 0
+        for e in d:
+            file.write(cols % (e.callcount, e.reccallcount, e.totaltime,
+                               e.inlinetime, label(e.code)))
+            count += 1
+            if limit is not None and count == limit:
+                return
+            ccount = 0
+            if e.calls:
+                for se in e.calls:
+                    file.write(cols % ("+%s" % se.callcount, se.reccallcount,
+                                       se.totaltime, se.inlinetime,
+                                       "+%s" % label(se.code)))
+                    count += 1
+                    ccount += 1
+                    if limit is not None and count == limit:
+                        return
+                    if climit is not None and ccount == climit:
+                        break
+
+    def freeze(self):
+        """Replace all references to code objects with string
+        descriptions; this makes it possible to pickle the instance."""
+
+        # this code is probably rather ickier than it needs to be!
+        for i in range(len(self.data)):
+            e = self.data[i]
+            if not isinstance(e.code, str):
+                self.data[i] = type(e)((label(e.code),) + e[1:])
+            if e.calls:
+                for j in range(len(e.calls)):
+                    se = e.calls[j]
+                    if not isinstance(se.code, str):
+                        e.calls[j] = type(se)((label(se.code),) + se[1:])
+
+_fn2mod = {}
+
+def label(code):
+    if isinstance(code, str):
+        return code
+    try:
+        mname = _fn2mod[code.co_filename]
+    except KeyError:
+        for k, v in sys.modules.items():
+            if v is None:
+                continue
+            if not hasattr(v, '__file__'):
+                continue
+            if not isinstance(v.__file__, str):
+                continue
+            if v.__file__.startswith(code.co_filename):
+                mname = _fn2mod[code.co_filename] = k
+                break
+        else:
+            mname = _fn2mod[code.co_filename] = '<%s>'%code.co_filename
+
+    return '%s:%d(%s)' % (mname, code.co_firstlineno, code.co_name)
+
+
+if __name__ == '__main__':
+    import os
+    sys.argv = sys.argv[1:]
+    if not sys.argv:
+        print >> sys.stderr, "usage: lsprof.py <script> <arguments...>"
+        sys.exit(2)
+    sys.path.insert(0, os.path.abspath(os.path.dirname(sys.argv[0])))
+    stats = profile(execfile, sys.argv[0], globals(), locals())
+    stats.sort()
+    stats.pprint()
diff --git a/bitbake/lib/pysh/pysh.py b/bitbake/lib/pysh/pysh.py
new file mode 100644
index 0000000000..b4e6145b51
--- /dev/null
+++ b/bitbake/lib/pysh/pysh.py
@@ -0,0 +1,167 @@
+# pysh.py - command processing for pysh.
+#
+# Copyright 2007 Patrick Mezard
+#
+# This software may be used and distributed according to the terms
+# of the GNU General Public License, incorporated herein by reference.
+
+import optparse
+import os
+import sys
+
+import interp
+
+SH_OPT = optparse.OptionParser(prog='pysh', usage="%prog [OPTIONS]", version='0.1')
+SH_OPT.add_option('-c', action='store_true', dest='command_string', default=None, 
+    help='A string that shall be interpreted by the shell as one or more commands')
+SH_OPT.add_option('--redirect-to', dest='redirect_to', default=None, 
+    help='Redirect script commands stdout and stderr to the specified file')
+# See utility_command in builtin.py about the reason for this flag.
+SH_OPT.add_option('--redirected', dest='redirected', action='store_true', default=False, 
+    help='Tell the interpreter that stdout and stderr are actually the same objects, which is really stdout')
+SH_OPT.add_option('--debug-parsing', action='store_true', dest='debug_parsing', default=False, 
+    help='Trace PLY execution')
+SH_OPT.add_option('--debug-tree', action='store_true', dest='debug_tree', default=False, 
+    help='Display the generated syntax tree.')
+SH_OPT.add_option('--debug-cmd', action='store_true', dest='debug_cmd', default=False, 
+    help='Trace command execution before parameters expansion and exit status.')
+SH_OPT.add_option('--debug-utility', action='store_true', dest='debug_utility', default=False, 
+    help='Trace utility calls, after parameters expansions')
+SH_OPT.add_option('--ast', action='store_true', dest='ast', default=False,
+    help='Encoded commands to execute in a subprocess')
+SH_OPT.add_option('--profile', action='store_true', default=False,
+    help='Profile pysh run')
+    
+    
+def split_args(args):
+    # Separate shell arguments from command ones
+    # Just stop at the first argument not starting with a dash. I know, this is completely broken,
+    # it ignores files starting with a dash or may take option values for command file. This is not
+    # supposed to happen for now
+    command_index = len(args)
+    for i,arg in enumerate(args):
+        if not arg.startswith('-'):
+            command_index = i
+            break
+            
+    return args[:command_index], args[command_index:]
+
+
+def fixenv(env):
+    path = env.get('PATH')
+    if path is not None:
+        parts = path.split(os.pathsep)
+        # Remove Windows utilities from PATH, they are useless at best and
+        # some of them (find) may be confused with other utilities.
+        parts = [p for p in parts if 'system32' not in p.lower()]
+        env['PATH'] = os.pathsep.join(parts)
+    if env.get('HOME') is None:
+        # Several utilities, including cvsps, cannot work without
+        # a defined HOME directory.
+        env['HOME'] = os.path.expanduser('~')
+    return env
+
+def _sh(cwd, shargs, cmdargs, options, debugflags=None, env=None):
+    if os.environ.get('PYSH_TEXT') != '1':
+        import msvcrt
+        for fp in (sys.stdin, sys.stdout, sys.stderr):
+            msvcrt.setmode(fp.fileno(), os.O_BINARY)
+
+    hgbin = os.environ.get('PYSH_HGTEXT') != '1'
+    
+    if debugflags is None:
+        debugflags = []
+        if options.debug_parsing:    debugflags.append('debug-parsing')
+        if options.debug_utility:    debugflags.append('debug-utility')
+        if options.debug_cmd:        debugflags.append('debug-cmd')
+        if options.debug_tree:       debugflags.append('debug-tree')
+    
+    if env is None:
+        env = fixenv(dict(os.environ))
+    if cwd is None:
+        cwd = os.getcwd()
+
+    if not cmdargs:
+        # Nothing to do
+        return 0
+
+    ast = None
+    command_file = None
+    if options.command_string:
+        input = cmdargs[0]
+        if not options.ast:
+            input += '\n'
+        else:
+            args, input = interp.decodeargs(input), None
+            env, ast = args
+            cwd = env.get('PWD', cwd)
+    else:
+        command_file = cmdargs[0]
+        arguments = cmdargs[1:]
+
+        prefix = interp.resolve_shebang(command_file, ignoreshell=True)
+        if prefix:
+            input = ' '.join(prefix + [command_file] + arguments)
+        else:
+            # Read commands from file
+            f = file(command_file)
+            try:
+                # Trailing newline to help the parser
+                input = f.read() + '\n'
+            finally:
+                f.close()
+    
+    redirect = None
+    try:
+        if options.redirected:
+            stdout = sys.stdout
+            stderr = stdout
+        elif options.redirect_to:
+            redirect = open(options.redirect_to, 'wb')
+            stdout = redirect
+            stderr = redirect
+        else:
+            stdout = sys.stdout
+            stderr = sys.stderr
+            
+        # TODO: set arguments to environment variables
+        opts = interp.Options()
+        opts.hgbinary = hgbin
+        ip = interp.Interpreter(cwd, debugflags, stdout=stdout, stderr=stderr,
+                                opts=opts)
+        try:
+            # Export given environment in shell object
+            for k,v in env.iteritems():
+                ip.get_env().export(k,v)
+            return ip.execute_script(input, ast, scriptpath=command_file)
+        finally:
+            ip.close()
+    finally:
+        if redirect is not None:
+            redirect.close()
+
+def sh(cwd=None, args=None, debugflags=None, env=None):
+    if args is None:
+        args = sys.argv[1:]
+    shargs, cmdargs = split_args(args)
+    options, shargs = SH_OPT.parse_args(shargs)
+
+    if options.profile:
+        import lsprof
+        p = lsprof.Profiler()
+        p.enable(subcalls=True)
+        try:
+            return _sh(cwd, shargs, cmdargs, options, debugflags, env)
+        finally:
+            p.disable()
+            stats = lsprof.Stats(p.getstats())
+            stats.sort()
+            stats.pprint(top=10, file=sys.stderr, climit=5)
+    else:
+        return _sh(cwd, shargs, cmdargs, options, debugflags, env)
+            
+def main():
+    sys.exit(sh())
+
+if __name__=='__main__':
+    main()
diff --git a/bitbake/lib/pysh/pyshlex.py b/bitbake/lib/pysh/pyshlex.py
new file mode 100644
index 0000000000..b977b5e869
--- /dev/null
+++ b/bitbake/lib/pysh/pyshlex.py
@@ -0,0 +1,888 @@
+# pyshlex.py - PLY compatible lexer for pysh.
+#
+# Copyright 2007 Patrick Mezard
+#
+# This software may be used and distributed according to the terms
+# of the GNU General Public License, incorporated herein by reference.
+
+# TODO:
+# - review all "char in 'abc'" snippets: the empty string can be matched
+# - test line continuations within quoted/expansion strings
+# - eof is buggy wrt sublexers
+# - the lexer cannot really work in pull mode as it would be required to run
+# PLY in pull mode. It was designed to work incrementally and it would not be
+# that hard to enable pull mode.
+import re
+try:
+    s = set()
+    del s
+except NameError:
+    from Set import Set as set
+
+from ply import lex
+from sherrors import *
+
+class NeedMore(Exception):
+    pass
+
+def is_blank(c):
+    return c in (' ', '\t')
+    
+_RE_DIGITS = re.compile(r'^\d+$')
+
+def are_digits(s):
+    return _RE_DIGITS.search(s) is not None
+
+_OPERATORS = dict([
+    ('&&', 'AND_IF'),
+    ('||', 'OR_IF'),
+    (';;', 'DSEMI'),
+    ('<<', 'DLESS'),
+    ('>>', 'DGREAT'),
+    ('<&', 'LESSAND'),
+    ('>&', 'GREATAND'),
+    ('<>', 'LESSGREAT'),
+    ('<<-', 'DLESSDASH'),
+    ('>|', 'CLOBBER'),
+    ('&', 'AMP'),
+    (';', 'COMMA'),
+    ('<', 'LESS'),
+    ('>', 'GREATER'),
+    ('(', 'LPARENS'),
+    (')', 'RPARENS'),
+])
+
+#Make a function to silence pychecker "Local variable shadows global"
+def make_partial_ops():
+    partials = {}
+    for k in _OPERATORS:
+        for i in range(1, len(k)+1):
+            partials[k[:i]] = None
+    return partials  
+
+_PARTIAL_OPERATORS = make_partial_ops()    
+        
+def is_partial_op(s):
+    """Return True if s matches a non-empty subpart of an operator starting
+    at its first character.
+    """
+    return s in _PARTIAL_OPERATORS
+    
+def is_op(s):
+    """If s matches an operator, returns the operator identifier. Return None
+    otherwise.
+    """
+    return _OPERATORS.get(s)
+
+_RESERVEDS = dict([
+    ('if', 'If'),
+    ('then', 'Then'),
+    ('else', 'Else'),
+    ('elif', 'Elif'),
+    ('fi', 'Fi'),
+    ('do', 'Do'),
+    ('done', 'Done'),
+    ('case', 'Case'),
+    ('esac', 'Esac'),
+    ('while', 'While'),
+    ('until', 'Until'),
+    ('for', 'For'),
+    ('{', 'Lbrace'),
+    ('}', 'Rbrace'),
+    ('!', 'Bang'),
+    ('in', 'In'),
+    ('|', 'PIPE'),
+])
+    
+def get_reserved(s):
+    return _RESERVEDS.get(s)
+    
+_RE_NAME = re.compile(r'^[0-9a-zA-Z_]+$')
+
+def is_name(s):
+    return _RE_NAME.search(s) is not None
+
+def find_chars(seq, chars):
+    for i,v in enumerate(seq):
+        if v in chars:
+            return i,v
+    return -1, None
+
+class WordLexer:
+    """WordLexer parse quoted or expansion expressions and return an expression
+    tree. The input string can be any well formed sequence beginning with quoting
+    or expansion character. Embedded expressions are handled recursively. The
+    resulting tree is made of lists and strings. Lists represent quoted or
+    expansion expressions. Each list first element is the opening separator,
+    the last one the closing separator. In-between can be any number of strings
+    or lists for sub-expressions. Non quoted/expansion expression can written as
+    strings or as lists with empty strings as starting and ending delimiters.
+    """
+
+    NAME_CHARSET = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_'
+    NAME_CHARSET = dict(zip(NAME_CHARSET, NAME_CHARSET))
+    
+    SPECIAL_CHARSET = '@*#?-$!0'
+    
+    #Characters which can be escaped depends on the current delimiters
+    ESCAPABLE = {
+        '`': set(['$', '\\', '`']),
+        '"': set(['$', '\\', '`', '"']),
+        "'": set(),
+    }
+        
+    def __init__(self, heredoc = False):
+        # _buffer is the unprocessed input characters buffer
+        self._buffer = []
+        # _stack is empty or contains a quoted list being processed
+        # (this is the DFS path to the quoted expression being evaluated).
+        self._stack = []
+        self._escapable = None
+        # True when parsing unquoted here documents
+        self._heredoc = heredoc
+        
+    def add(self, data, eof=False):
+        """Feed the lexer with more data. If the quoted expression can be
+        delimited, return a tuple (expr, remaining) containing the expression
+        tree and the unconsumed data.
+        Otherwise, raise NeedMore.
+        """
+        self._buffer += list(data)
+        self._parse(eof)
+        
+        result = self._stack[0]
+        remaining = ''.join(self._buffer)
+        self._stack = []
+        self._buffer = []
+        return result, remaining
+        
+    def _is_escapable(self, c, delim=None):
+        if delim is None:
+            if self._heredoc:
+                # Backslashes works as if they were double quoted in unquoted
+                # here-documents
+                delim = '"'
+            else:
+                if len(self._stack)<=1:
+                    return True
+                delim = self._stack[-2][0]
+            
+        escapables = self.ESCAPABLE.get(delim, None)
+        return escapables is None or c in escapables
+        
+    def _parse_squote(self, buf, result, eof):
+        if not buf:
+            raise NeedMore()
+        try:
+            pos = buf.index("'")
+        except ValueError:
+            raise NeedMore()
+        result[-1] += ''.join(buf[:pos])
+        result += ["'"]
+        return pos+1, True
+        
+    def _parse_bquote(self, buf, result, eof):
+        if not buf:
+            raise NeedMore()
+            
+        if buf[0]=='\n':
+            #Remove line continuations
+            result[:] = ['', '', '']
+        elif self._is_escapable(buf[0]):
+            result[-1] += buf[0]
+            result += ['']
+        else:
+            #Keep as such
+            result[:] = ['', '\\'+buf[0], '']
+        
+        return 1, True
+        
+    def _parse_dquote(self, buf, result, eof):
+        if not buf:
+            raise NeedMore()
+        pos, sep = find_chars(buf, '$\\`"')
+        if pos==-1:
+            raise NeedMore()
+            
+        result[-1] += ''.join(buf[:pos])
+        if sep=='"':
+            result += ['"']
+            return pos+1, True
+        else:
+            #Keep everything until the separator and defer processing
+            return pos, False
+            
+    def _parse_command(self, buf, result, eof):
+        if not buf:
+            raise NeedMore()
+
+        chars = '$\\`"\''
+        if result[0] == '$(':
+            chars += ')'
+        pos, sep = find_chars(buf, chars)
+        if pos == -1:
+            raise NeedMore()
+            
+        result[-1] += ''.join(buf[:pos])
+        if (result[0]=='$(' and sep==')') or (result[0]=='`' and sep=='`'):
+            result += [sep]
+            return pos+1, True
+        else:
+            return pos, False
+            
+    def _parse_parameter(self, buf, result, eof):
+        if not buf:
+            raise NeedMore()
+            
+        pos, sep = find_chars(buf, '$\\`"\'}')
+        if pos==-1:
+            raise NeedMore()
+            
+        result[-1] += ''.join(buf[:pos])
+        if sep=='}':
+            result += [sep]
+            return pos+1, True
+        else:
+            return pos, False
+            
+    def _parse_dollar(self, buf, result, eof):
+        sep = result[0]
+        if sep=='$':            
+            if not buf:
+                #TODO: handle empty $
+                raise NeedMore()
+            if buf[0]=='(':
+                if len(buf)==1:
+                    raise NeedMore()
+                    
+                if buf[1]=='(':
+                    result[0] = '$(('
+                    buf[:2] = []
+                else:
+                    result[0] = '$('
+                    buf[:1] = []
+                
+            elif buf[0]=='{':
+                result[0] = '${'
+                buf[:1] = []
+            else:
+                if buf[0] in self.SPECIAL_CHARSET:
+                    result[-1] = buf[0]
+                    read = 1
+                else:
+                    for read,c in enumerate(buf):
+                        if c not in self.NAME_CHARSET:
+                            break
+                    else:
+                        if not eof:
+                            raise NeedMore()
+                        read += 1
+                        
+                    result[-1] += ''.join(buf[0:read])
+                    
+                if not result[-1]:
+                    result[:] = ['', result[0], '']
+                else:
+                    result += [''] 
+                return read,True
+        
+        sep = result[0]    
+        if sep=='$(':
+            parsefunc = self._parse_command
+        elif sep=='${':
+            parsefunc = self._parse_parameter
+        else:
+            raise NotImplementedError()
+            
+        pos, closed = parsefunc(buf, result, eof)
+        return pos, closed
+
+    def _parse(self, eof):
+        buf = self._buffer
+        stack = self._stack
+        recurse = False
+    
+        while 1:
+            if not stack or recurse:
+                if not buf:
+                    raise NeedMore()
+                if buf[0] not in ('"\\`$\''):
+                    raise ShellSyntaxError('Invalid quoted string sequence')
+                stack.append([buf[0], ''])
+                buf[:1] = []
+                recurse = False
+                
+            result = stack[-1]
+            if result[0]=="'":
+                parsefunc = self._parse_squote
+            elif result[0]=='\\':
+                parsefunc = self._parse_bquote
+            elif result[0]=='"':
+                parsefunc = self._parse_dquote
+            elif result[0]=='`':
+                parsefunc = self._parse_command
+            elif result[0][0]=='$':
+                parsefunc = self._parse_dollar
+            else:
+                raise NotImplementedError()
+                
+            read, closed = parsefunc(buf, result, eof)
+                
+            buf[:read] = []
+            if closed:
+                if len(stack)>1:
+                    #Merge in parent expression
+                    parsed = stack.pop()
+                    stack[-1] += [parsed]
+                    stack[-1] += ['']
+                else:
+                    break
+            else:
+                recurse = True
+
+def normalize_wordtree(wtree):
+    """Fold back every literal sequence (delimited with empty strings) into
+    parent sequence.
+    """
+    def normalize(wtree):
+        result = []
+        for part in wtree[1:-1]:
+            if isinstance(part, list):
+                part = normalize(part)
+                if part[0]=='':
+                    #Move the part content back at current level
+                    result += part[1:-1]
+                    continue
+            elif not part:
+                #Remove empty strings
+                continue
+            result.append(part)
+        if not result:
+            result = ['']    
+        return [wtree[0]] + result + [wtree[-1]]
+                
+    return normalize(wtree)
+    
+                
+def make_wordtree(token, here_document=False):
+    """Parse a delimited token and return a tree similar to the ones returned by
+    WordLexer. token may contain any combinations of expansion/quoted fields and
+    non-ones.
+    """    
+    tree = ['']
+    remaining = token
+    delimiters = '\\$`'
+    if not here_document:
+        delimiters += '\'"'
+    
+    while 1:
+        pos, sep = find_chars(remaining, delimiters)
+        if pos==-1:
+            tree += [remaining, '']
+            return normalize_wordtree(tree)
+        tree.append(remaining[:pos])
+        remaining = remaining[pos:]
+        
+        try:
+            result, remaining = WordLexer(heredoc = here_document).add(remaining, True)
+        except NeedMore:
+            raise ShellSyntaxError('Invalid token "%s"')
+        tree.append(result)
+        
+                
+def wordtree_as_string(wtree):
+    """Rewrite an expression tree generated by make_wordtree as string."""
+    def visit(node, output):
+        for child in node:
+            if isinstance(child, list):
+                visit(child, output)
+            else:
+                output.append(child)
+    
+    output = []
+    visit(wtree, output)
+    return ''.join(output)
+    
+    
+def unquote_wordtree(wtree):
+    """Fold the word tree while removing quotes everywhere. Other expansion
+    sequences are joined as such.
+    """
+    def unquote(wtree):
+        unquoted = []
+        if wtree[0] in ('', "'", '"', '\\'):
+            wtree = wtree[1:-1]
+            
+        for part in wtree:
+            if isinstance(part, list):
+                part = unquote(part)
+            unquoted.append(part)
+        return ''.join(unquoted)
+            
+    return unquote(wtree)
+    
+    
+class HereDocLexer:
+    """HereDocLexer delimits whatever comes from the here-document starting newline
+    not included to the closing delimiter line included.
+    """
+    def __init__(self, op, delim):
+        assert op in ('<<', '<<-')
+        if not delim:
+            raise ShellSyntaxError('invalid here document delimiter %s' % str(delim))
+            
+        self._op = op
+        self._delim = delim
+        self._buffer = []
+        self._token = []
+        
+    def add(self, data, eof):
+        """If the here-document was delimited, return a tuple (content, remaining).
+        Raise NeedMore() otherwise.
+        """
+        self._buffer += list(data)
+        self._parse(eof)
+        token = ''.join(self._token)
+        remaining = ''.join(self._buffer)
+        self._token, self._remaining = [], []
+        return token, remaining
+    
+    def _parse(self, eof):
+        while 1:
+            #Look for first unescaped newline. Quotes may be ignored
+            escaped = False
+            for i,c in enumerate(self._buffer):
+                if escaped:
+                    escaped = False
+                elif c=='\\':
+                    escaped = True
+                elif c=='\n':
+                    break
+            else:
+                i = -1
+                    
+            if i==-1 or self._buffer[i]!='\n':
+                if not eof:
+                    raise NeedMore()
+                #No more data, maybe the last line is closing delimiter
+                line = ''.join(self._buffer)
+                eol = ''
+                self._buffer[:] = []
+            else:
+                line = ''.join(self._buffer[:i])
+                eol = self._buffer[i]
+                self._buffer[:i+1] = []
+            
+            if self._op=='<<-':
+                line = line.lstrip('\t')
+                
+            if line==self._delim:
+                break
+                
+            self._token += [line, eol]
+            if i==-1:
+                break
+    
+class Token:
+    #TODO: check this is still in use
+    OPERATOR = 'OPERATOR'
+    WORD = 'WORD'
+    
+    def __init__(self):
+        self.value = ''
+        self.type = None
+        
+    def __getitem__(self, key):
+        #Behave like a two elements tuple
+        if key==0:
+            return self.type
+        if key==1:
+            return self.value
+        raise IndexError(key)
+               
+               
+class HereDoc:
+    def __init__(self, op, name=None):
+        self.op = op
+        self.name = name
+        self.pendings = []
+               
+TK_COMMA        = 'COMMA'
+TK_AMPERSAND    = 'AMP'
+TK_OP           = 'OP'
+TK_TOKEN        = 'TOKEN'
+TK_COMMENT      = 'COMMENT'
+TK_NEWLINE      = 'NEWLINE' 
+TK_IONUMBER     = 'IO_NUMBER'
+TK_ASSIGNMENT   = 'ASSIGNMENT_WORD'
+TK_HERENAME     = 'HERENAME'
+
+class Lexer:
+    """Main lexer.
+    
+    Call add() until the script AST is returned.
+    """
+    # Here-document handling makes the whole thing more complex because they basically
+    # force tokens to be reordered: here-content must come right after the operator
+    # and the here-document name, while some other tokens might be following the
+    # here-document expression on the same line.
+    #
+    # So, here-doc states are basically:
+    #   *self._state==ST_NORMAL
+    #       - self._heredoc.op is None: no here-document
+    #       - self._heredoc.op is not None but name is: here-document operator matched,
+    #           waiting for the document name/delimiter
+    #       - self._heredoc.op and name are not None: here-document is ready, following
+    #           tokens are being stored and will be pushed again when the document is
+    #           completely parsed.
+    #   *self._state==ST_HEREDOC
+    #       - The here-document is being delimited by self._herelexer. Once it is done
+    #           the content is pushed in front of the pending token list then all these
+    #           tokens are pushed once again.
+    ST_NORMAL       = 'ST_NORMAL'
+    ST_OP           = 'ST_OP'
+    ST_BACKSLASH    = 'ST_BACKSLASH'
+    ST_QUOTED       = 'ST_QUOTED'
+    ST_COMMENT      = 'ST_COMMENT'
+    ST_HEREDOC      = 'ST_HEREDOC'
+    
+    #Match end of backquote strings
+    RE_BACKQUOTE_END = re.compile(r'(?<!\\)(`)')
+
+    def __init__(self, parent_state = None):
+        self._input = []
+        self._pos = 0
+        
+        self._token = ''
+        self._type = TK_TOKEN
+        
+        self._state = self.ST_NORMAL
+        self._parent_state = parent_state
+        self._wordlexer = None
+        
+        self._heredoc = HereDoc(None)
+        self._herelexer = None
+        
+        ### Following attributes are not used for delimiting token and can safely
+        ### be changed after here-document detection (see _push_toke)
+        
+        # Count the number of tokens following a 'For' reserved word. Needed to
+        # return an 'In' reserved word if it comes in third place.
+        self._for_count = None
+        
+    def add(self, data, eof=False):
+        """Feed the lexer with data.
+        
+        When eof is set to True, returns unconsumed data or raise if the lexer
+        is in the middle of a delimiting operation.
+        Raise NeedMore otherwise.
+        """
+        self._input += list(data)
+        self._parse(eof)
+        self._input[:self._pos] = []
+        return ''.join(self._input)
+        
+    def _parse(self, eof):            
+        while self._state:
+            if self._pos>=len(self._input):
+                if not eof:
+                    raise NeedMore()
+                elif self._state not in (self.ST_OP, self.ST_QUOTED, self.ST_HEREDOC):
+                    #Delimit the current token and leave cleanly
+                    self._push_token('')
+                    break
+                else:
+                    #Let the sublexer handle the eof themselves
+                    pass
+                
+            if self._state==self.ST_NORMAL:
+                self._parse_normal()
+            elif self._state==self.ST_COMMENT:
+                self._parse_comment()
+            elif self._state==self.ST_OP:
+                self._parse_op(eof)
+            elif self._state==self.ST_QUOTED:
+                self._parse_quoted(eof)
+            elif self._state==self.ST_HEREDOC:
+                self._parse_heredoc(eof)
+            else:
+                assert False, "Unknown state " + str(self._state)
+                
+        if self._heredoc.op is not None:
+            raise ShellSyntaxError('missing here-document delimiter')
+                
+    def _parse_normal(self):
+        c = self._input[self._pos]
+        if c=='\n':
+            self._push_token(c)
+            self._token = c
+            self._type = TK_NEWLINE
+            self._push_token('')
+            self._pos += 1
+        elif c in ('\\', '\'', '"', '`', '$'):
+            self._state = self.ST_QUOTED
+        elif is_partial_op(c):
+            self._push_token(c)
+            
+            self._type = TK_OP
+            self._token += c
+            self._pos += 1
+            self._state = self.ST_OP
+        elif is_blank(c):
+            self._push_token(c)
+            
+            #Discard blanks
+            self._pos += 1
+        elif self._token:
+            self._token += c
+            self._pos += 1
+        elif c=='#':
+            self._state = self.ST_COMMENT
+            self._type = TK_COMMENT
+            self._pos += 1
+        else:
+            self._pos += 1
+            self._token += c          
+                
+    def _parse_op(self, eof):
+        assert self._token
+        
+        while 1:
+            if self._pos>=len(self._input):
+                if not eof:
+                    raise NeedMore()
+                c = ''
+            else:                
+                c = self._input[self._pos]
+                
+            op = self._token + c
+            if c and is_partial_op(op):
+                #Still parsing an operator
+                self._token = op
+                self._pos += 1
+            else:            
+                #End of operator
+                self._push_token(c)                    
+                self._state = self.ST_NORMAL
+                break
+                
+    def _parse_comment(self):
+        while 1:
+            if self._pos>=len(self._input):
+                raise NeedMore()
+                
+            c = self._input[self._pos]
+            if c=='\n':
+                #End of comment, do not consume the end of line
+                self._state = self.ST_NORMAL
+                break
+            else:
+                self._token += c
+                self._pos += 1
+                
+    def _parse_quoted(self, eof):
+        """Precondition: the starting backquote/dollar is still in the input queue."""
+        if not self._wordlexer:
+            self._wordlexer = WordLexer()
+        
+        if self._pos<len(self._input):
+             #Transfer input queue character into the subparser
+            input = self._input[self._pos:]
+            self._pos += len(input)
+            
+        wtree, remaining = self._wordlexer.add(input, eof)
+        self._wordlexer = None
+        self._token += wordtree_as_string(wtree)
+        
+        #Put unparsed character back in the input queue
+        if remaining:
+            self._input[self._pos:self._pos] = list(remaining)          
+        self._state = self.ST_NORMAL
+        
+    def _parse_heredoc(self, eof):
+        assert not self._token
+        
+        if self._herelexer is None:
+            self._herelexer = HereDocLexer(self._heredoc.op, self._heredoc.name)
+        
+        if self._pos<len(self._input):
+             #Transfer input queue character into the subparser
+            input = self._input[self._pos:]
+            self._pos += len(input)
+        
+        self._token, remaining = self._herelexer.add(input, eof)
+        
+        #Reset here-document state
+        self._herelexer = None
+        heredoc, self._heredoc = self._heredoc, HereDoc(None)
+        if remaining:
+            self._input[self._pos:self._pos] = list(remaining)
+        self._state = self.ST_NORMAL
+        
+        #Push pending tokens
+        heredoc.pendings[:0] = [(self._token, self._type, heredoc.name)]
+        for token, type, delim in heredoc.pendings:
+            self._token = token
+            self._type = type
+            self._push_token(delim)
+                     
+    def _push_token(self, delim):
+        if not self._token:
+            return 0
+            
+        if self._heredoc.op is not None:
+            if self._heredoc.name is None:
+                #Here-document name
+                if self._type!=TK_TOKEN:
+                    raise ShellSyntaxError("expecting here-document name, got '%s'" % self._token)
+                self._heredoc.name = unquote_wordtree(make_wordtree(self._token))
+                self._type = TK_HERENAME
+            else:
+                #Capture all tokens until the newline starting the here-document
+                if self._type==TK_NEWLINE:
+                    assert self._state==self.ST_NORMAL
+                    self._state = self.ST_HEREDOC    
+                
+                self._heredoc.pendings.append((self._token, self._type, delim))    
+                self._token = ''
+                self._type = TK_TOKEN
+                return 1
+                
+        # BEWARE: do not change parser state from here to the end of the function:
+        # when parsing between an here-document operator to the end of the line
+        # tokens are stored in self._heredoc.pendings. Therefore, they will not
+        # reach the section below.
+                    
+        #Check operators
+        if self._type==TK_OP:
+            #False positive because of partial op matching
+            op = is_op(self._token)
+            if not op:
+                self._type = TK_TOKEN
+            else:
+                #Map to the specific operator
+                self._type = op
+                if self._token in ('<<', '<<-'):
+                    #Done here rather than in _parse_op because there is no need
+                    #to change the parser state since we are still waiting for
+                    #the here-document name
+                    if self._heredoc.op is not None:
+                        raise ShellSyntaxError("syntax error near token '%s'" % self._token)
+                    assert self._heredoc.op is None
+                    self._heredoc.op = self._token
+                
+        if self._type==TK_TOKEN:            
+            if '=' in self._token and not delim:
+                if self._token.startswith('='):
+                    #Token is a WORD... a TOKEN that is.
+                    pass
+                else:
+                    prev = self._token[:self._token.find('=')]
+                    if is_name(prev):
+                        self._type = TK_ASSIGNMENT
+                    else:
+                        #Just a token (unspecified)
+                        pass
+            else:
+                reserved = get_reserved(self._token)
+                if reserved is not None:
+                    if reserved=='In' and self._for_count!=2:
+                        #Sorry, not a reserved word after all
+                        pass
+                    else:
+                        self._type = reserved
+                        if reserved in ('For', 'Case'):
+                            self._for_count = 0                    
+                elif are_digits(self._token) and delim in ('<', '>'):
+                    #Detect IO_NUMBER
+                    self._type = TK_IONUMBER
+                elif self._token==';':
+                    self._type = TK_COMMA
+                elif self._token=='&':
+                    self._type = TK_AMPERSAND
+        elif self._type==TK_COMMENT:
+            #Comments are not part of sh grammar, ignore them
+            self._token = ''
+            self._type = TK_TOKEN
+            return 0
+        
+        if self._for_count is not None:
+            #Track token count in 'For' expression to detect 'In' reserved words.
+            #Can only be in third position, no need to go beyond
+            self._for_count += 1
+            if self._for_count==3:
+                self._for_count = None
+                
+        self.on_token((self._token, self._type))
+        self._token = ''
+        self._type = TK_TOKEN
+        return 1
+                        
+    def on_token(self, token):
+        raise NotImplementedError
+                 
+
+tokens = [
+    TK_TOKEN,
+# To silence yacc unused token warnings
+#    TK_COMMENT,
+    TK_NEWLINE,
+    TK_IONUMBER,
+    TK_ASSIGNMENT,
+    TK_HERENAME,
+]            
+
+#Add specific operators
+tokens += _OPERATORS.values()
+#Add reserved words
+tokens += _RESERVEDS.values()
+            
+class PLYLexer(Lexer):
+    """Bridge Lexer and PLY lexer interface."""
+    def __init__(self):
+        Lexer.__init__(self)
+        self._tokens = []
+        self._current = 0
+        self.lineno = 0
+
+    def on_token(self, token):
+        value, type = token
+
+        self.lineno = 0
+        t = lex.LexToken()
+        t.value = value
+        t.type = type
+        t.lexer = self
+        t.lexpos = 0
+        t.lineno = 0
+        
+        self._tokens.append(t)
+        
+    def is_empty(self):
+        return not bool(self._tokens)
+        
+    #PLY compliant interface
+    def token(self):
+        if self._current>=len(self._tokens):
+            return None
+        t = self._tokens[self._current]
+        self._current += 1
+        return t      
+        
+        
+def get_tokens(s):
+    """Parse the input string and return a tuple (tokens, unprocessed) where
+    tokens is a list of parsed tokens and unprocessed is the part of the input
+    string left untouched by the lexer.
+    """
+    lexer = PLYLexer()
+    untouched = lexer.add(s, True) 
+    tokens = []
+    while 1:
+        token = lexer.token()
+        if token is None:
+            break
+        tokens.append(token)
+        
+    tokens = [(t.value, t.type) for t in tokens]
+    return tokens, untouched        
diff --git a/bitbake/lib/pysh/pyshyacc.py b/bitbake/lib/pysh/pyshyacc.py
new file mode 100644
index 0000000000..3d9510c0c3
--- /dev/null
+++ b/bitbake/lib/pysh/pyshyacc.py
@@ -0,0 +1,772 @@
+# pyshyacc.py - PLY grammar definition for pysh
+#
+# Copyright 2007 Patrick Mezard
+#
+# This software may be used and distributed according to the terms
+# of the GNU General Public License, incorporated herein by reference.
+
+"""PLY grammar file.
+"""
+import sys
+
+import pyshlex
+tokens = pyshlex.tokens
+
+from ply import yacc
+import sherrors
+    
+class IORedirect:
+    def __init__(self, op, filename, io_number=None):
+        self.op = op
+        self.filename = filename
+        self.io_number = io_number
+        
+class HereDocument:
+    def __init__(self, op, name, content, io_number=None):
+        self.op = op
+        self.name = name
+        self.content = content
+        self.io_number = io_number
+
+def make_io_redirect(p):
+    """Make an IORedirect instance from the input 'io_redirect' production."""
+    name, io_number, io_target = p
+    assert name=='io_redirect'
+    
+    if io_target[0]=='io_file':
+        io_type, io_op, io_file = io_target
+        return IORedirect(io_op, io_file, io_number)
+    elif io_target[0]=='io_here':
+        io_type, io_op, io_name, io_content = io_target
+        return HereDocument(io_op, io_name, io_content, io_number)
+    else:
+        assert False, "Invalid IO redirection token %s" % repr(io_type)
+        
+class SimpleCommand:
+    """
+    assigns contains (name, value) pairs.
+    """
+    def __init__(self, words, redirs, assigns):
+        self.words = list(words)
+        self.redirs = list(redirs)
+        self.assigns = list(assigns)
+
+class Pipeline:
+    def __init__(self, commands, reverse_status=False):
+        self.commands = list(commands)
+        assert self.commands    #Grammar forbids this
+        self.reverse_status = reverse_status
+        
+class AndOr:
+    def __init__(self, op, left, right):
+        self.op = str(op)
+        self.left = left
+        self.right = right
+        
+class ForLoop:
+    def __init__(self, name, items, cmds):
+        self.name = str(name)
+        self.items = list(items)
+        self.cmds = list(cmds)
+        
+class WhileLoop:
+    def __init__(self, condition, cmds):
+        self.condition = list(condition)
+        self.cmds = list(cmds)
+        
+class UntilLoop:
+    def __init__(self, condition, cmds):
+        self.condition = list(condition)
+        self.cmds = list(cmds)
+
+class FunDef:
+    def __init__(self, name, body):
+        self.name = str(name)
+        self.body = body
+        
+class BraceGroup:
+    def __init__(self, cmds):
+        self.cmds = list(cmds)
+        
+class IfCond:
+    def __init__(self, cond, if_cmds, else_cmds):
+        self.cond = list(cond)
+        self.if_cmds = if_cmds
+        self.else_cmds = else_cmds
+
+class Case:
+    def __init__(self, name, items):
+        self.name = name
+        self.items = items
+        
+class SubShell:
+    def __init__(self, cmds):
+        self.cmds = cmds
+
+class RedirectList:
+    def __init__(self, cmd, redirs):
+        self.cmd = cmd
+        self.redirs = list(redirs)
+        
+def get_production(productions, ptype):
+    """productions must be a list of production tuples like (name, obj) where
+    name is the production string identifier.
+    Return the first production named 'ptype'. Raise KeyError if None can be
+    found.
+    """
+    for production in productions:
+        if production is not None and production[0]==ptype:
+            return production
+    raise KeyError(ptype)
+    
+#-------------------------------------------------------------------------------
+# PLY grammar definition
+#-------------------------------------------------------------------------------
+
+def p_multiple_commands(p):
+    """multiple_commands : newline_sequence
+                         | complete_command
+                         | multiple_commands complete_command"""
+    if len(p)==2:
+        if p[1] is not None:
+            p[0] = [p[1]]
+        else:
+            p[0] = []
+    else:
+        p[0] = p[1] + [p[2]]
+
+def p_complete_command(p):
+    """complete_command : list separator
+                        | list"""
+    if len(p)==3 and p[2] and p[2][1] == '&':
+        p[0] = ('async', p[1])
+    else:
+        p[0] = p[1]
+                 
+def p_list(p):
+    """list : list separator_op and_or
+            |                   and_or"""
+    if len(p)==2:
+        p[0] = [p[1]]
+    else:
+        #if p[2]!=';':
+        #    raise NotImplementedError('AND-OR list asynchronous execution is not implemented')
+        p[0] = p[1] + [p[3]]
+       
+def p_and_or(p):
+    """and_or : pipeline
+              | and_or AND_IF linebreak pipeline
+              | and_or OR_IF  linebreak pipeline"""
+    if len(p)==2:
+        p[0] = p[1]
+    else:
+        p[0] = ('and_or', AndOr(p[2], p[1], p[4]))
+        
+def p_maybe_bang_word(p):
+    """maybe_bang_word : Bang"""
+    p[0] = ('maybe_bang_word', p[1])
+            
+def p_pipeline(p):
+    """pipeline : pipe_sequence
+                | bang_word pipe_sequence"""
+    if len(p)==3:
+        p[0] = ('pipeline', Pipeline(p[2][1:], True))
+    else:
+        p[0] = ('pipeline', Pipeline(p[1][1:]))
+
+def p_pipe_sequence(p):
+    """pipe_sequence : command
+                     | pipe_sequence PIPE linebreak command"""
+    if len(p)==2:
+        p[0] = ['pipe_sequence', p[1]]
+    else:
+        p[0] = p[1] + [p[4]]
+
+def p_command(p):
+    """command : simple_command
+               | compound_command
+               | compound_command redirect_list
+               | function_definition"""
+        
+    if p[1][0] in ( 'simple_command', 
+                    'for_clause',
+                    'while_clause',
+                    'until_clause',
+                    'case_clause',
+                    'if_clause',
+                    'function_definition',
+                    'subshell',
+                    'brace_group',):
+        if len(p) == 2:
+            p[0] = p[1]
+        else:
+            p[0] = ('redirect_list', RedirectList(p[1], p[2][1:]))
+    else:
+        raise NotImplementedError('%s command is not implemented' % repr(p[1][0]))
+
+def p_compound_command(p):
+    """compound_command : brace_group
+                        | subshell
+                        | for_clause
+                        | case_clause
+                        | if_clause
+                        | while_clause
+                        | until_clause"""
+    p[0] = p[1]
+
+def p_subshell(p):
+    """subshell : LPARENS compound_list RPARENS"""
+    p[0] = ('subshell', SubShell(p[2][1:]))
+
+def p_compound_list(p):
+    """compound_list : term
+                     | newline_list term
+                     |              term separator
+                     | newline_list term separator"""
+    productions = p[1:]           
+    try:
+        sep = get_production(productions, 'separator')
+        if sep[1]!=';':
+            raise NotImplementedError()
+    except KeyError:
+        pass
+    term = get_production(productions, 'term')
+    p[0] = ['compound_list'] + term[1:]
+
+def p_term(p):
+    """term : term separator and_or
+            |                and_or"""
+    if len(p)==2:
+        p[0] = ['term', p[1]]
+    else:
+        if p[2] is not None and p[2][1] == '&':
+            p[0] = ['term', ('async', p[1][1:])] + [p[3]]
+        else:
+            p[0] = p[1] + [p[3]]
+            
+def p_maybe_for_word(p):
+    # Rearrange 'For' priority wrt TOKEN. See p_for_word
+    """maybe_for_word : For"""
+    p[0] = ('maybe_for_word', p[1])
+
+def p_for_clause(p):
+    """for_clause : for_word name linebreak                            do_group
+                  | for_word name linebreak in          sequential_sep do_group
+                  | for_word name linebreak in wordlist sequential_sep do_group"""
+    productions = p[1:]
+    do_group = get_production(productions, 'do_group')
+    try:
+        items = get_production(productions, 'in')[1:]
+    except KeyError:
+        raise NotImplementedError('"in" omission is not implemented')
+        
+    try:
+        items = get_production(productions, 'wordlist')[1:]
+    except KeyError:
+        items = []
+        
+    name = p[2]
+    p[0] = ('for_clause', ForLoop(name, items, do_group[1:]))
+
+def p_name(p):
+    """name : token""" #Was NAME instead of token
+    p[0] = p[1]
+
+def p_in(p):
+    """in : In"""
+    p[0] = ('in', p[1])
+
+def p_wordlist(p):
+    """wordlist : wordlist token
+                |          token"""
+    if len(p)==2:
+        p[0] = ['wordlist', ('TOKEN', p[1])]
+    else:
+        p[0] = p[1] + [('TOKEN', p[2])]
+
+def p_case_clause(p):
+    """case_clause : Case token linebreak in linebreak case_list    Esac
+                   | Case token linebreak in linebreak case_list_ns Esac
+                   | Case token linebreak in linebreak              Esac"""
+    if len(p) < 8:
+        items = []
+    else:
+        items = p[6][1:]
+    name = p[2]
+    p[0] = ('case_clause', Case(name, [c[1] for c in items]))
+       
+def p_case_list_ns(p):
+    """case_list_ns : case_list case_item_ns
+                    |           case_item_ns"""
+    p_case_list(p)
+      
+def p_case_list(p):
+    """case_list : case_list case_item
+                 |           case_item"""
+    if len(p)==2:
+        p[0] = ['case_list', p[1]]
+    else:
+        p[0] = p[1] + [p[2]]
+        
+def p_case_item_ns(p):
+    """case_item_ns :         pattern RPARENS               linebreak
+                    |         pattern RPARENS compound_list linebreak
+                    | LPARENS pattern RPARENS               linebreak
+                    | LPARENS pattern RPARENS compound_list linebreak"""
+    p_case_item(p)
+                 
+def p_case_item(p):
+    """case_item :         pattern RPARENS linebreak     DSEMI linebreak
+                 |         pattern RPARENS compound_list DSEMI linebreak
+                 | LPARENS pattern RPARENS linebreak     DSEMI linebreak
+                 | LPARENS pattern RPARENS compound_list DSEMI linebreak"""
+    if len(p) < 7:
+        name = p[1][1:]
+    else:
+        name = p[2][1:]
+
+    try:
+        cmds = get_production(p[1:], "compound_list")[1:]
+    except KeyError:
+        cmds = []
+
+    p[0] = ('case_item', (name, cmds))
+                 
+def p_pattern(p):
+    """pattern :              token
+               | pattern PIPE token"""
+    if len(p)==2:
+        p[0] = ['pattern', ('TOKEN', p[1])]
+    else:
+        p[0] = p[1] + [('TOKEN', p[2])]
+
+def p_maybe_if_word(p):
+    # Rearrange 'If' priority wrt TOKEN. See p_if_word
+    """maybe_if_word : If"""
+    p[0] = ('maybe_if_word', p[1])
+
+def p_maybe_then_word(p):
+    # Rearrange 'Then' priority wrt TOKEN. See p_then_word
+    """maybe_then_word : Then"""
+    p[0] = ('maybe_then_word', p[1])
+                 
+def p_if_clause(p):
+    """if_clause : if_word compound_list then_word compound_list else_part Fi
+                 | if_word compound_list then_word compound_list           Fi"""
+    else_part = []
+    if len(p)==7:
+        else_part = p[5]
+    p[0] = ('if_clause', IfCond(p[2][1:], p[4][1:], else_part))
+                 
+def p_else_part(p):
+    """else_part : Elif compound_list then_word compound_list else_part
+                 | Elif compound_list then_word compound_list
+                 | Else compound_list"""
+    if len(p)==3:
+        p[0] = p[2][1:]
+    else:
+        else_part = []
+        if len(p)==6:
+            else_part = p[5]
+        p[0] = ('elif', IfCond(p[2][1:], p[4][1:], else_part))
+                 
+def p_while_clause(p):
+    """while_clause : While compound_list do_group"""
+    p[0] = ('while_clause', WhileLoop(p[2][1:], p[3][1:]))
+    
+def p_maybe_until_word(p):
+    # Rearrange 'Until' priority wrt TOKEN. See p_until_word
+    """maybe_until_word : Until"""
+    p[0] = ('maybe_until_word', p[1])
+           
+def p_until_clause(p):
+    """until_clause : until_word compound_list do_group"""
+    p[0] = ('until_clause', UntilLoop(p[2][1:], p[3][1:]))
+                 
+def p_function_definition(p):
+    """function_definition : fname LPARENS RPARENS linebreak function_body"""
+    p[0] = ('function_definition', FunDef(p[1], p[5]))
+                 
+def p_function_body(p):
+    """function_body : compound_command
+                     | compound_command redirect_list"""
+    if len(p)!=2:
+        raise NotImplementedError('functions redirections lists are not implemented')    
+    p[0] = p[1]    
+
+def p_fname(p):
+    """fname : TOKEN""" #Was NAME instead of token
+    p[0] = p[1]
+
+def p_brace_group(p):
+    """brace_group : Lbrace compound_list Rbrace"""
+    p[0] = ('brace_group', BraceGroup(p[2][1:]))
+
+def p_maybe_done_word(p):
+    #See p_assignment_word for details.
+    """maybe_done_word : Done"""
+    p[0] = ('maybe_done_word', p[1])
+
+def p_maybe_do_word(p):
+    """maybe_do_word : Do"""
+    p[0] = ('maybe_do_word', p[1])
+
+def p_do_group(p):
+    """do_group : do_word compound_list done_word"""
+    #Do group contains a list of AndOr
+    p[0] = ['do_group'] + p[2][1:]
+
+def p_simple_command(p):
+    """simple_command : cmd_prefix cmd_word cmd_suffix
+                      | cmd_prefix cmd_word
+                      | cmd_prefix
+                      | cmd_name cmd_suffix
+                      | cmd_name"""
+    words, redirs, assigns = [], [], []
+    for e in p[1:]:
+        name = e[0]
+        if name in ('cmd_prefix', 'cmd_suffix'):
+            for sube in e[1:]:
+                subname = sube[0]
+                if subname=='io_redirect':
+                    redirs.append(make_io_redirect(sube))
+                elif subname=='ASSIGNMENT_WORD':
+                    assigns.append(sube)
+                else:
+                    words.append(sube)
+        elif name in ('cmd_word', 'cmd_name'):
+            words.append(e)
+            
+    cmd = SimpleCommand(words, redirs, assigns)
+    p[0] = ('simple_command', cmd)
+
+def p_cmd_name(p):
+    """cmd_name : TOKEN"""
+    p[0] = ('cmd_name', p[1])
+    
+def p_cmd_word(p):
+    """cmd_word : token"""
+    p[0] = ('cmd_word', p[1])
+
+def p_maybe_assignment_word(p):
+    #See p_assignment_word for details.
+    """maybe_assignment_word : ASSIGNMENT_WORD"""
+    p[0] = ('maybe_assignment_word', p[1])
+    
+def p_cmd_prefix(p):
+    """cmd_prefix :            io_redirect
+                  | cmd_prefix io_redirect
+                  |            assignment_word
+                  | cmd_prefix assignment_word"""
+    try:
+        prefix = get_production(p[1:], 'cmd_prefix')
+    except KeyError:
+        prefix = ['cmd_prefix']
+        
+    try:
+        value = get_production(p[1:], 'assignment_word')[1]
+        value = ('ASSIGNMENT_WORD', value.split('=', 1))
+    except KeyError:        
+        value = get_production(p[1:], 'io_redirect')
+    p[0] = prefix + [value]
+                                  
+def p_cmd_suffix(p):
+    """cmd_suffix   :            io_redirect
+                    | cmd_suffix io_redirect
+                    |            token
+                    | cmd_suffix token
+                    |            maybe_for_word
+                    | cmd_suffix maybe_for_word
+                    |            maybe_done_word
+                    | cmd_suffix maybe_done_word
+                    |            maybe_do_word
+                    | cmd_suffix maybe_do_word
+                    |            maybe_until_word
+                    | cmd_suffix maybe_until_word
+                    |            maybe_assignment_word
+                    | cmd_suffix maybe_assignment_word
+                    |            maybe_if_word
+                    | cmd_suffix maybe_if_word
+                    |            maybe_then_word
+                    | cmd_suffix maybe_then_word
+                    |            maybe_bang_word
+                    | cmd_suffix maybe_bang_word"""
+    try:
+        suffix = get_production(p[1:], 'cmd_suffix')
+        token = p[2]
+    except KeyError:
+        suffix = ['cmd_suffix']
+        token = p[1]
+        
+    if isinstance(token, tuple):
+        if token[0]=='io_redirect':
+            p[0] = suffix + [token]
+        else:
+            #Convert maybe_*  to TOKEN if necessary
+            p[0] = suffix + [('TOKEN', token[1])]
+    else:
+        p[0] = suffix + [('TOKEN', token)]
+                 
+def p_redirect_list(p):
+    """redirect_list : io_redirect
+                     | redirect_list io_redirect"""
+    if len(p) == 2:
+        p[0] = ['redirect_list', make_io_redirect(p[1])]
+    else:
+        p[0] = p[1] + [make_io_redirect(p[2])]
+    
+def p_io_redirect(p):
+    """io_redirect :           io_file
+                   | IO_NUMBER io_file
+                   |           io_here
+                   | IO_NUMBER io_here"""
+    if len(p)==3:
+        p[0] = ('io_redirect', p[1], p[2])
+    else:
+        p[0] = ('io_redirect', None, p[1])
+    
+def p_io_file(p):
+    #Return the tuple (operator, filename)
+    """io_file : LESS      filename
+               | LESSAND   filename
+               | GREATER   filename
+               | GREATAND  filename
+               | DGREAT    filename
+               | LESSGREAT filename
+               | CLOBBER   filename"""
+    #Extract the filename from the file
+    p[0] = ('io_file', p[1], p[2][1])
+
+def p_filename(p):
+    #Return the filename
+    """filename : TOKEN"""
+    p[0] = ('filename', p[1])
+        
+def p_io_here(p):
+    """io_here : DLESS here_end
+               | DLESSDASH here_end"""
+    p[0] = ('io_here', p[1], p[2][1], p[2][2])
+
+def p_here_end(p):
+    """here_end : HERENAME TOKEN"""
+    p[0] = ('here_document', p[1], p[2])
+    
+def p_newline_sequence(p):
+    # Nothing in the grammar can handle leading NEWLINE productions, so add
+    # this one with the lowest possible priority relatively to newline_list.
+    """newline_sequence : newline_list"""
+    p[0] = None
+    
+def p_newline_list(p):
+    """newline_list : NEWLINE
+                    | newline_list NEWLINE"""
+    p[0] = None
+                    
+def p_linebreak(p):
+    """linebreak : newline_list
+                 | empty"""
+    p[0] = None
+
+def p_separator_op(p):                 
+    """separator_op : COMMA
+                    | AMP"""
+    p[0] = p[1]
+
+def p_separator(p):
+    """separator : separator_op linebreak
+                 | newline_list"""
+    if len(p)==2:
+        #Ignore newlines
+        p[0] = None
+    else:
+        #Keep the separator operator
+        p[0] = ('separator', p[1])
+                 
+def p_sequential_sep(p):
+    """sequential_sep : COMMA linebreak
+                      | newline_list"""
+    p[0] = None
+
+# Low priority TOKEN => for_word conversion.
+# Let maybe_for_word be used as a token when necessary in higher priority
+# rules. 
+def p_for_word(p):
+    """for_word : maybe_for_word"""
+    p[0] = p[1]
+
+def p_if_word(p):
+    """if_word : maybe_if_word"""
+    p[0] = p[1]
+
+def p_then_word(p):
+    """then_word : maybe_then_word"""
+    p[0] = p[1]
+
+def p_done_word(p):
+    """done_word : maybe_done_word"""
+    p[0] = p[1]
+
+def p_do_word(p):
+    """do_word : maybe_do_word"""
+    p[0] = p[1]
+    
+def p_until_word(p):
+    """until_word : maybe_until_word"""
+    p[0] = p[1]
+    
+def p_assignment_word(p):
+    """assignment_word : maybe_assignment_word"""
+    p[0] = ('assignment_word', p[1][1])
+    
+def p_bang_word(p):
+    """bang_word : maybe_bang_word"""
+    p[0] = ('bang_word', p[1][1])
+
+def p_token(p):
+    """token : TOKEN
+             | Fi"""
+    p[0] = p[1]
+
+def p_empty(p):
+    'empty :'
+    p[0] = None
+    
+# Error rule for syntax errors
+def p_error(p):
+    msg = []
+    w = msg.append
+    w('%r\n' % p)
+    w('followed by:\n')
+    for i in range(5):
+        n = yacc.token()
+        if not n:
+            break
+        w('  %r\n' % n)
+    raise sherrors.ShellSyntaxError(''.join(msg))
+
+# Build the parser
+try:
+    import pyshtables
+except ImportError:
+    yacc.yacc(tabmodule = 'pyshtables')
+else:
+    yacc.yacc(tabmodule = 'pysh.pyshtables', write_tables = 0, debug = 0)
+
+
+def parse(input, eof=False, debug=False):
+    """Parse a whole script at once and return the generated AST and unconsumed
+    data in a tuple.
+    
+    NOTE: eof is probably meaningless for now, the parser being unable to work
+    in pull mode. It should be set to True.
+    """
+    lexer = pyshlex.PLYLexer()
+    remaining = lexer.add(input, eof)
+    if lexer.is_empty():
+        return [], remaining
+    if debug:
+        debug = 2
+    return yacc.parse(lexer=lexer, debug=debug), remaining
+
+#-------------------------------------------------------------------------------
+# AST rendering helpers
+#-------------------------------------------------------------------------------    
+
+def format_commands(v):
+    """Return a tree made of strings and lists. Make command trees easier to
+    display.
+    """
+    if isinstance(v, list):
+        return [format_commands(c) for c in v]
+    if isinstance(v, tuple):
+        if len(v)==2 and isinstance(v[0], str) and not isinstance(v[1], str):
+            if v[0] == 'async':
+                return ['AsyncList', map(format_commands, v[1])]
+            else:
+                #Avoid decomposing tuples like ('pipeline', Pipeline(...))
+                return format_commands(v[1])
+        return format_commands(list(v))
+    elif isinstance(v, IfCond):
+        name = ['IfCond']
+        name += ['if', map(format_commands, v.cond)]
+        name += ['then', map(format_commands, v.if_cmds)]
+        name += ['else', map(format_commands, v.else_cmds)]
+        return name
+    elif isinstance(v, ForLoop):
+        name = ['ForLoop']
+        name += [repr(v.name)+' in ', map(str, v.items)]
+        name += ['commands', map(format_commands, v.cmds)]
+        return name
+    elif isinstance(v, AndOr):
+        return [v.op, format_commands(v.left), format_commands(v.right)]
+    elif isinstance(v, Pipeline):
+        name = 'Pipeline'
+        if v.reverse_status:
+            name = '!' + name
+        return [name, format_commands(v.commands)]
+    elif isinstance(v, SimpleCommand):
+        name = ['SimpleCommand']
+        if v.words:                
+            name += ['words', map(str, v.words)]
+        if v.assigns:
+            assigns = [tuple(a[1]) for a in v.assigns]
+            name += ['assigns', map(str, assigns)]
+        if v.redirs:
+            name += ['redirs', map(format_commands, v.redirs)]
+        return name
+    elif isinstance(v, RedirectList):
+        name = ['RedirectList']
+        if v.redirs:
+            name += ['redirs', map(format_commands, v.redirs)]
+        name += ['command', format_commands(v.cmd)]
+        return name
+    elif isinstance(v, IORedirect):
+        return ' '.join(map(str, (v.io_number, v.op, v.filename)))
+    elif isinstance(v, HereDocument):
+        return ' '.join(map(str, (v.io_number, v.op, repr(v.name), repr(v.content))))
+    elif isinstance(v, SubShell):
+        return ['SubShell', map(format_commands, v.cmds)]
+    else:
+        return repr(v)
+             
+def print_commands(cmds, output=sys.stdout):
+    """Pretty print a command tree."""
+    def print_tree(cmd, spaces, output):
+        if isinstance(cmd, list):
+            for c in cmd:
+                print_tree(c, spaces + 3, output)              
+        else:
+            print >>output, ' '*spaces + str(cmd)
+    
+    formatted = format_commands(cmds)
+    print_tree(formatted, 0, output)
+    
+    
+def stringify_commands(cmds): 
+    """Serialize a command tree as a string.
+    
+    Returned string is not pretty and is currently used for unit tests only.
+    """   
+    def stringify(value):
+        output = []
+        if isinstance(value, list):
+            formatted = []
+            for v in value:
+                formatted.append(stringify(v))
+            formatted = ' '.join(formatted)
+            output.append(''.join(['<', formatted, '>']))
+        else:
+            output.append(value)
+        return ' '.join(output)
+            
+    return stringify(format_commands(cmds))
+    
+        
+def visit_commands(cmds, callable):
+    """Visit the command tree and execute callable on every Pipeline and 
+    SimpleCommand instances.
+    """
+    if isinstance(cmds, (tuple, list)):
+        map(lambda c: visit_commands(c,callable), cmds)
+    elif isinstance(cmds, (Pipeline, SimpleCommand)):
+        callable(cmds)
diff --git a/bitbake/lib/pysh/sherrors.py b/bitbake/lib/pysh/sherrors.py
new file mode 100644
index 0000000000..1d5bd53b3a
--- /dev/null
+++ b/bitbake/lib/pysh/sherrors.py
@@ -0,0 +1,41 @@
+# sherrors.py - shell errors and signals
+#
+# Copyright 2007 Patrick Mezard
+#
+# This software may be used and distributed according to the terms
+# of the GNU General Public License, incorporated herein by reference.
+
+"""Define shell exceptions and error codes.
+"""
+
+class ShellError(Exception):
+    pass
+
+class ShellSyntaxError(ShellError):
+    pass
+    
+class UtilityError(ShellError):
+    """Raised upon utility syntax error (option or operand error)."""
+    pass
+   
+class ExpansionError(ShellError):
+    pass
+     
+class CommandNotFound(ShellError):
+    """Specified command was not found."""
+    pass
+    
+class RedirectionError(ShellError):
+    pass
+    
+class VarAssignmentError(ShellError):
+    """Variable assignment error."""
+    pass
+    
+class ExitSignal(ShellError):
+    """Exit signal."""
+    pass
+    
+class ReturnSignal(ShellError):
+    """Exit signal."""
+    pass
\ No newline at end of file
diff --git a/bitbake/lib/pysh/subprocess_fix.py b/bitbake/lib/pysh/subprocess_fix.py
new file mode 100644
index 0000000000..46eca22802
--- /dev/null
+++ b/bitbake/lib/pysh/subprocess_fix.py
@@ -0,0 +1,77 @@
+# subprocess - Subprocesses with accessible I/O streams
+#
+# For more information about this module, see PEP 324.
+#
+# This module should remain compatible with Python 2.2, see PEP 291.
+#
+# Copyright (c) 2003-2005 by Peter Astrand <astrand@lysator.liu.se>
+#
+# Licensed to PSF under a Contributor Agreement.
+# See http://www.python.org/2.4/license for licensing details.
+
+def list2cmdline(seq):
+    """
+    Translate a sequence of arguments into a command line
+    string, using the same rules as the MS C runtime:
+
+    1) Arguments are delimited by white space, which is either a
+       space or a tab.
+
+    2) A string surrounded by double quotation marks is
+       interpreted as a single argument, regardless of white space
+       contained within.  A quoted string can be embedded in an
+       argument.
+
+    3) A double quotation mark preceded by a backslash is
+       interpreted as a literal double quotation mark.
+
+    4) Backslashes are interpreted literally, unless they
+       immediately precede a double quotation mark.
+
+    5) If backslashes immediately precede a double quotation mark,
+       every pair of backslashes is interpreted as a literal
+       backslash.  If the number of backslashes is odd, the last
+       backslash escapes the next double quotation mark as
+       described in rule 3.
+    """
+
+    # See
+    # http://msdn.microsoft.com/library/en-us/vccelng/htm/progs_12.asp
+    result = []
+    needquote = False
+    for arg in seq:
+        bs_buf = []
+
+        # Add a space to separate this argument from the others
+        if result:
+            result.append(' ')
+
+        needquote = (" " in arg) or ("\t" in arg) or ("|" in arg) or arg == ""
+        if needquote:
+            result.append('"')
+
+        for c in arg:
+            if c == '\\':
+                # Don't know if we need to double yet.
+                bs_buf.append(c)
+            elif c == '"':
+                # Double backspaces.
+                result.append('\\' * len(bs_buf)*2)
+                bs_buf = []
+                result.append('\\"')
+            else:
+                # Normal char
+                if bs_buf:
+                    result.extend(bs_buf)
+                    bs_buf = []
+                result.append(c)
+
+        # Add remaining backspaces, if any.
+        if bs_buf:
+            result.extend(bs_buf)
+
+        if needquote:
+            result.extend(bs_buf)
+            result.append('"')
+            
+    return ''.join(result)