wic: implement 'wic write' command

This command writes image to the media or another file with
the possibility to expand partitions to fill free target space.

[YOCTO #11278]

(From OE-Core rev: ac5fc0d691aad66ac01a5cde34c331c928e9e25a)

Signed-off-by: Ed Bartosh <ed.bartosh@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

2 files changed, 186 insertions, 0 deletions

diff --git a/scripts/lib/wic/engine.py b/scripts/lib/wic/engine.py
index 4ffb08d1c8..303f323b83 100644
--- a/scripts/lib/wic/engine.py
+++ b/scripts/lib/wic/engine.py
@@ -31,6 +31,8 @@
 import logging
 import os
 import tempfile
+import json
+import subprocess
 
 from collections import namedtuple, OrderedDict
 from distutils.spawn import find_executable
@@ -340,6 +342,143 @@ class Disk:
                 raise err
         self._put_part_image(pnum)
 
+    def write(self, target, expand):
+        """Write disk image to the media or file."""
+        def write_sfdisk_script(outf, parts):
+            for key, val in parts['partitiontable'].items():
+                if key in ("partitions", "device", "firstlba", "lastlba"):
+                    continue
+                if key == "id":
+                    key = "label-id"
+                outf.write("{}: {}\n".format(key, val))
+            outf.write("\n")
+            for part in parts['partitiontable']['partitions']:
+                line = ''
+                for name in ('attrs', 'name', 'size', 'type', 'uuid'):
+                    if name == 'size' and part['type'] == 'f':
+                        # don't write size for extended partition
+                        continue
+                    val = part.get(name)
+                    if val:
+                        line += '{}={}, '.format(name, val)
+                if line:
+                    line = line[:-2] # strip ', '
+                if part.get('bootable'):
+                    line += ' ,bootable'
+                outf.write("{}\n".format(line))
+            outf.flush()
+
+        def read_ptable(path):
+            out = exec_cmd("{} -dJ {}".format(self.sfdisk, path))
+            return json.loads(out)
+
+        def write_ptable(parts, target):
+            with tempfile.NamedTemporaryFile(prefix="wic-sfdisk-", mode='w') as outf:
+                write_sfdisk_script(outf, parts)
+                cmd = "{} --no-reread {} < {} 2>/dev/null".format(self.sfdisk, target, outf.name)
+                try:
+                    subprocess.check_output(cmd, shell=True)
+                except subprocess.CalledProcessError as err:
+                    raise WicError("Can't run '{}' command: {}".format(cmd, err))
+
+        if expand is None:
+            sparse_copy(self.imagepath, target)
+        else:
+            # copy first sectors that may contain bootloader
+            sparse_copy(self.imagepath, target, length=2048 * self._lsector_size)
+
+            # copy source partition table to the target
+            parts = read_ptable(self.imagepath)
+            write_ptable(parts, target)
+
+            # get size of unpartitioned space
+            free = None
+            for line in exec_cmd("{} -F {}".format(self.sfdisk, target)).splitlines():
+                if line.startswith("Unpartitioned space ") and line.endswith("sectors"):
+                    free = int(line.split()[-2])
+            if free is None:
+                raise WicError("Can't get size of unpartitioned space")
+
+            # calculate expanded partitions sizes
+            sizes = {}
+            for num, part in enumerate(parts['partitiontable']['partitions'], 1):
+                if num in expand:
+                    if expand[num] != 0: # don't resize partition if size is set to 0
+                        sectors = expand[num] // self._lsector_size
+                        free -= sectors - part['size']
+                        part['size'] = sectors
+                        sizes[num] = sectors
+                elif part['type'] != 'f':
+                    sizes[num] = -1
+
+            for num, part in enumerate(parts['partitiontable']['partitions'], 1):
+                if sizes.get(num) == -1:
+                    part['size'] += free // len(sizes)
+
+            # write resized partition table to the target
+            write_ptable(parts, target)
+
+            # read resized partition table
+            parts = read_ptable(target)
+
+            # copy partitions content
+            for num, part in enumerate(parts['partitiontable']['partitions'], 1):
+                pnum = str(num)
+                fstype = self.partitions[pnum].fstype
+
+                # copy unchanged partition
+                if part['size'] == self.partitions[pnum].size // self._lsector_size:
+                    logger.info("copying unchanged partition {}".format(pnum))
+                    sparse_copy(self._get_part_image(pnum), target, seek=part['start'] * self._lsector_size)
+                    continue
+
+                # resize or re-create partitions
+                if fstype.startswith('ext') or fstype.startswith('fat') or \
+                   fstype.startswith('linux-swap'):
+
+                    partfname = None
+                    with tempfile.NamedTemporaryFile(prefix="wic-part{}-".format(pnum)) as partf:
+                        partfname = partf.name
+
+                    if fstype.startswith('ext'):
+                        logger.info("resizing ext partition {}".format(pnum))
+                        partimg = self._get_part_image(pnum)
+                        sparse_copy(partimg, partfname)
+                        exec_cmd("{} -pf {}".format(self.e2fsck, partfname))
+                        exec_cmd("{} {} {}s".format(\
+                                 self.resize2fs, partfname, part['size']))
+                    elif fstype.startswith('fat'):
+                        logger.info("copying content of the fat partition {}".format(pnum))
+                        with tempfile.TemporaryDirectory(prefix='wic-fatdir-') as tmpdir:
+                            # copy content to the temporary directory
+                            cmd = "{} -snompi {} :: {}".format(self.mcopy,
+                                                               self._get_part_image(pnum),
+                                                               tmpdir)
+                            exec_cmd(cmd)
+                            # create new msdos partition
+                            label = part.get("name")
+                            label_str = "-n {}".format(label) if label else ''
+
+                            cmd = "{} {} -C {} {}".format(self.mkdosfs, label_str, partfname,
+                                                          part['size'])
+                            exec_cmd(cmd)
+                            # copy content from the temporary directory to the new partition
+                            cmd = "{} -snompi {} {}/* ::".format(self.mcopy, partfname, tmpdir)
+                            exec_cmd(cmd, as_shell=True)
+                    elif fstype.startswith('linux-swap'):
+                        logger.info("creating swap partition {}".format(pnum))
+                        label = part.get("name")
+                        label_str = "-L {}".format(label) if label else ''
+                        uuid = part.get("uuid")
+                        uuid_str = "-U {}".format(uuid) if uuid else ''
+                        with open(partfname, 'w') as sparse:
+                            os.ftruncate(sparse.fileno(), part['size'] * self._lsector_size)
+                        exec_cmd("{} {} {} {}".format(self.mkswap, label_str, uuid_str, partfname))
+                    sparse_copy(partfname, target, seek=part['start'] * self._lsector_size)
+                    os.unlink(partfname)
+                elif part['type'] != 'f':
+                    logger.warn("skipping partition {}: unsupported fstype {}".format(pnum, fstype))
+
 def wic_ls(args, native_sysroot):
     """List contents of partitioned image or vfat partition."""
     disk = Disk(args.path.image, native_sysroot)
@@ -370,6 +509,13 @@ def wic_rm(args, native_sysroot):
     disk = Disk(args.path.image, native_sysroot)
     disk.remove(args.path.part, args.path.path)
 
+def wic_write(args, native_sysroot):
+    """
+    Write image to a target device.
+    """
+    disk = Disk(args.image, native_sysroot, ('fat', 'ext', 'swap'))
+    disk.write(args.target, args.expand)
+
 def find_canned(scripts_path, file_name):
     """
     Find a file either by its path or by name in the canned files dir.
diff --git a/scripts/lib/wic/help.py b/scripts/lib/wic/help.py
index 99912cd400..ccd3382324 100644
--- a/scripts/lib/wic/help.py
+++ b/scripts/lib/wic/help.py
@@ -468,6 +468,46 @@ DESCRIPTION
     containing the tools(parted and mtools) to use.
 """
 
+wic_write_usage = """
+
+ Write image to a device
+
+ usage: wic write <image> <target device> [--expand [rules]] [--native-sysroot <path>]
+
+ This command writes wic image to a target device (USB stick, SD card etc).
+
+ See 'wic help write' for more detailed instructions.
+
+"""
+
+wic_write_help = """
+
+NAME
+    wic write - write wic image to a device
+
+SYNOPSIS
+    wic write <image> <target>
+    wic write <image> <target> --expand auto
+    wic write <image> <target> --expand 1:100M-2:300M
+    wic write <image> <target> --native-sysroot <path>
+
+DESCRIPTION
+    This command writes wic image to a target device (USB stick, SD card etc)
+
+        $ wic write ./tmp/deploy/images/qemux86-64/core-image-minimal-qemux86-64.wic /dev/sdb
+
+    The --expand option is used to resize image partitions.
+    --expand auto expands partitions to occupy all free space available on the target device.
+    It's also possible to specify expansion rules in a format
+    <partition>:<size>[-<partition>:<size>...] for one or more partitions.
+    Specifying size 0 will keep partition unmodified.
+    Note: Resizing boot partition can result in non-bootable image for non-EFI images. It is
+    recommended to use size 0 for boot partition to keep image bootable.
+
+    The --native-sysroot option is used to specify the path to the native sysroot
+    containing the tools(parted, resize2fs) to use.
+"""
+
 wic_plugins_help = """
 
 NAME