kernel/gen_kheaders.sh

   1 #!/bin/sh
   2 # SPDX-License-Identifier: GPL-2.0
   3
   4 # This script generates an archive consisting of kernel headers
   5 # for CONFIG_IKHEADERS.
   6 set -e
   7 sfile="$(readlink -f "$0")"
   8 outdir="$(pwd)"
   9 tarfile=$1
  10 cpio_dir=$outdir/$tarfile.tmp
  11
  12 dir_list="
  13 include/
  14 arch/$SRCARCH/include/
  15 "
  16
  17 # Support incremental builds by skipping archive generation
  18 # if timestamps of files being archived are not changed.
  19
  20 # This block is useful for debugging the incremental builds.
  21 # Uncomment it for debugging.
  22 # if [ ! -f /tmp/iter ]; then iter=1; echo 1 > /tmp/iter;
  23 # else iter=$(($(cat /tmp/iter) + 1)); echo $iter > /tmp/iter; fi
  24 # find $all_dirs -name "*.h" | xargs ls -l > /tmp/ls-$iter
  25
  26 all_dirs=
  27 if [ "$building_out_of_srctree" ]; then
  28         for d in $dir_list; do
  29                 all_dirs="$all_dirs $srctree/$d"
  30         done
  31 fi
  32 all_dirs="$all_dirs $dir_list"
  33
  34 # include/generated/compile.h is ignored because it is touched even when none
  35 # of the source files changed.
  36 #
  37 # When Kconfig regenerates include/generated/autoconf.h, its timestamp is
  38 # updated, but the contents might be still the same. When any CONFIG option is
  39 # changed, Kconfig touches the corresponding timestamp file include/config/*.h.
  40 # Hence, the md5sum detects the configuration change anyway. We do not need to
  41 # check include/generated/autoconf.h explicitly.
  42 #
  43 # Ignore them for md5 calculation to avoid pointless regeneration.
  44 headers_md5="$(find $all_dirs -name "*.h"                       |
  45                 grep -v "include/generated/compile.h"   |
  46                 grep -v "include/generated/autoconf.h"  |
  47                 xargs ls -l | md5sum | cut -d ' ' -f1)"
  48
  49 # Any changes to this script will also cause a rebuild of the archive.
  50 this_file_md5="$(ls -l $sfile | md5sum | cut -d ' ' -f1)"
  51 if [ -f $tarfile ]; then tarfile_md5="$(md5sum $tarfile | cut -d ' ' -f1)"; fi
  52 if [ -f kernel/kheaders.md5 ] &&
  53         [ "$(head -n 1 kernel/kheaders.md5)" = "$headers_md5" ] &&
  54         [ "$(head -n 2 kernel/kheaders.md5 | tail -n 1)" = "$this_file_md5" ] &&
  55         [ "$(tail -n 1 kernel/kheaders.md5)" = "$tarfile_md5" ]; then
  56                 exit
  57 fi
  58
  59 if [ "${quiet}" != "silent_" ]; then
  60        echo "  GEN     $tarfile"
  61 fi
  62
  63 rm -rf $cpio_dir
  64 mkdir $cpio_dir
  65
  66 if [ "$building_out_of_srctree" ]; then
  67         (
  68                 cd $srctree
  69                 for f in $dir_list
  70                         do find "$f" -name "*.h";
  71                 done | cpio --quiet -pd $cpio_dir
  72         )
  73 fi
  74
  75 # The second CPIO can complain if files already exist which can happen with out
  76 # of tree builds having stale headers in srctree. Just silence CPIO for now.
  77 for f in $dir_list;
  78         do find "$f" -name "*.h";
  79 done | cpio --quiet -pd $cpio_dir >/dev/null 2>&1
  80
  81 # Remove comments except SDPX lines
  82 find $cpio_dir -type f -print0 |
  83         xargs -0 -P8 -n1 perl -pi -e 'BEGIN {undef $/;}; s/\/\*((?!SPDX).)*?\*\///smg;'
  84
  85 # Create archive and try to normalize metadata for reproducibility.
  86 # For compatibility with older versions of tar, files are fed to tar
  87 # pre-sorted, as --sort=name might not be available.
  88 find $cpio_dir -printf "./%P\n" | LC_ALL=C sort | \
  89     tar "${KBUILD_BUILD_TIMESTAMP:+--mtime=$KBUILD_BUILD_TIMESTAMP}" \
  90     --owner=0 --group=0 --numeric-owner --no-recursion \
  91     -I $XZ -cf $tarfile -C $cpio_dir/ -T - > /dev/null
  92
  93 echo $headers_md5 > kernel/kheaders.md5
  94 echo "$this_file_md5" >> kernel/kheaders.md5
  95 echo "$(md5sum $tarfile | cut -d ' ' -f1)" >> kernel/kheaders.md5
  96
  97 rm -rf $cpio_dir