busybox: always start do_compile with orig config files

When compiling busybox a second time (e.g. with `compile -f`), busybox
can use an altered autoconf.h file for compiling, which can ultimately
produces different and unwanted binaries.

This can produce errors like this one:

ERROR: busybox-1.35.0-r0 do_package: Error executing a python function in exec_func_python() autogenerated:
The stack trace of python calls that resulted in this exception/failure was:
File: 'exec_func_python() autogenerated', lineno: 2, function: <module>
     0001:
 *** 0002:ptest_update_alternatives(d)
     0003:
File: '…/poky/meta/classes/ptest.bbclass', lineno: 100, function: ptest_update_alternatives
     0096:        for alt_name, alt_link, alt_target, _ in alternatives:
     0097:            # Some alternatives are for man pages,
     0098:            # check if the alternative is in PATH
     0099:            if os.path.dirname(alt_link) in bin_paths:
 *** 0100:                os.symlink(alt_target, os.path.join(ptest_bindir, alt_name))
     0101:}
     0102:
     0103:do_configure_ptest_base[dirs] = "${B}"
     0104:do_compile_ptest_base[dirs] = "${B}"
Exception: FileExistsError: [Errno 17] File exists: '/bin/busybox.suid' -> '…/busybox/1.35.0-r0/package/usr/lib/busybox/ptest/bin/login'

This happens because ALTERNATIVE:busybox contains `/bin/login` twice,
initially that's because `/bin/login` is present in both
busybox.links.suid and busybox.links.nosuid. The reason for that is
because of the altered autoconf.h.

Steps to reproduce above error:

<add ptest to distro configs>
bitbake busybox -c clean
bitbake busybox -c package -f
bitbake busybox -c compile -f
bitbake busybox -c package -f

This patch guards against potential bugs by:

- making a backup of .config and autoconf.h that have matching
  timestamps.
- make sure do_compile always starts with these files.
- restore .config and autoconf.h at the end of do_compile.

(From OE-Core rev: 7ef76eaf5b68d52afdc4292bbe20309e29bb464a)

Signed-off-by: Antonin Godard <antoningodard@pm.me>
Signed-off-by: Steve Sakoman <steve@sakoman.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 16 insertions, 8 deletions

diff --git a/meta/recipes-core/busybox/busybox.inc b/meta/recipes-core/busybox/busybox.inc
index 3553376582..616a23258a 100644
--- a/meta/recipes-core/busybox/busybox.inc
+++ b/meta/recipes-core/busybox/busybox.inc
@@ -139,6 +139,10 @@ do_configure () {
         do_prepare_config
         merge_config.sh -m .config ${@" ".join(find_cfgs(d))}
         cml1_do_configure
+
+        # Save a copy of .config and autoconf.h.
+        cp .config .config.orig
+        cp include/autoconf.h include/autoconf.h.orig
 }
 
 do_compile() {
@@ -146,13 +150,14 @@ do_compile() {
         if [ "${BUILD_REPRODUCIBLE_BINARIES}" = "1" ]; then
                 export KCONFIG_NOTIMESTAMP=1
         fi
+
+        # Ensure we start do_compile with the original .config and autoconf.h.
+        # These files should always have matching timestamps.
+        cp .config.orig .config
+        cp include/autoconf.h.orig include/autoconf.h
+
         if [ "${BUSYBOX_SPLIT_SUID}" = "1" -a x`grep "CONFIG_FEATURE_INDIVIDUAL=y" .config` = x ]; then
                 # split the .config into two parts, and make two busybox binaries
-                if [ -e .config.orig ]; then
-                        # Need to guard again an interrupted do_compile - restore any backup
-                        cp .config.orig .config
-                fi
-                cp .config .config.orig
                 oe_runmake busybox.cfg.suid
                 oe_runmake busybox.cfg.nosuid
 
@@ -189,15 +194,18 @@ do_compile() {
                         bbfatal "busybox suid binary incorrectly provides /bin/sh"
                 fi
 
-                # copy .config.orig back to .config, because the install process may check this file
-                cp .config.orig .config
                 # cleanup
-                rm .config.orig .config.app.suid .config.app.nosuid .config.disable.apps .config.nonapps
+                rm .config.app.suid .config.app.nosuid .config.disable.apps .config.nonapps
         else
                 oe_runmake busybox_unstripped
                 cp busybox_unstripped busybox
                 oe_runmake busybox.links
         fi
+
+        # restore original .config and autoconf.h, because the install process
+        # may check these files
+        cp .config.orig .config
+        cp include/autoconf.h.orig include/autoconf.h
 }
 
 do_install () {