linux-stable/scripts/gen_initramfs_list.sh
Maxime Bizon 9e5ec86152 kbuild: fix spurious initramfs rebuild
When gen_initramfs_list is used to generate make dependencies, it
includes symbolic links, for which make tracks the link target. Any
change to that target will cause an initramfs rebuild, even if the
symlink points to something outside of the initramfs directory.

If the target happens to be /tmp, the rebuild occurs for each kernel
build, since gen_initramfs_list uses mktemp...

Proposed way to fix it is to omit symbolic links from generated
dependencies, but this has a small drawback: changing perm/owner on a
symlink will go unnoticed.

Signed-off-by: Maxime Bizon <mbizon@freebox.fr>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2009-04-11 08:18:12 +02:00

300 lines
7 KiB
Bash

#!/bin/bash
# Copyright (C) Martin Schlemmer <azarah@nosferatu.za.org>
# Copyright (C) 2006 Sam Ravnborg <sam@ravnborg.org>
#
# Released under the terms of the GNU GPL
#
# Generate a cpio packed initramfs. It uses gen_init_cpio to generate
# the cpio archive, and then compresses it.
# The script may also be used to generate the inputfile used for gen_init_cpio
# This script assumes that gen_init_cpio is located in usr/ directory
# error out on errors
set -e
usage() {
cat << EOF
Usage:
$0 [-o <file>] [-u <uid>] [-g <gid>] {-d | <cpio_source>} ...
-o <file> Create compressed initramfs file named <file> using
gen_init_cpio and compressor depending on the extension
-u <uid> User ID to map to user ID 0 (root).
<uid> is only meaningful if <cpio_source> is a
directory. "squash" forces all files to uid 0.
-g <gid> Group ID to map to group ID 0 (root).
<gid> is only meaningful if <cpio_source> is a
directory. "squash" forces all files to gid 0.
<cpio_source> File list or directory for cpio archive.
If <cpio_source> is a .cpio file it will be used
as direct input to initramfs.
-d Output the default cpio list.
All options except -o and -l may be repeated and are interpreted
sequentially and immediately. -u and -g states are preserved across
<cpio_source> options so an explicit "-u 0 -g 0" is required
to reset the root/group mapping.
EOF
}
# awk style field access
# $1 - field number; rest is argument string
field() {
shift $1 ; echo $1
}
list_default_initramfs() {
# echo usr/kinit/kinit
:
}
default_initramfs() {
cat <<-EOF >> ${output}
# This is a very simple, default initramfs
dir /dev 0755 0 0
nod /dev/console 0600 0 0 c 5 1
dir /root 0700 0 0
# file /kinit usr/kinit/kinit 0755 0 0
# slink /init kinit 0755 0 0
EOF
}
filetype() {
local argv1="$1"
# symlink test must come before file test
if [ -L "${argv1}" ]; then
echo "slink"
elif [ -f "${argv1}" ]; then
echo "file"
elif [ -d "${argv1}" ]; then
echo "dir"
elif [ -b "${argv1}" -o -c "${argv1}" ]; then
echo "nod"
elif [ -p "${argv1}" ]; then
echo "pipe"
elif [ -S "${argv1}" ]; then
echo "sock"
else
echo "invalid"
fi
return 0
}
list_print_mtime() {
:
}
print_mtime() {
local my_mtime="0"
if [ -e "$1" ]; then
my_mtime=$(find "$1" -printf "%T@\n" | sort -r | head -n 1)
fi
echo "# Last modified: ${my_mtime}" >> ${output}
echo "" >> ${output}
}
list_parse() {
[ ! -L "$1" ] && echo "$1 \\" || :
}
# for each file print a line in following format
# <filetype> <name> <path to file> <octal mode> <uid> <gid>
# for links, devices etc the format differs. See gen_init_cpio for details
parse() {
local location="$1"
local name="${location/${srcdir}//}"
# change '//' into '/'
name="${name//\/\///}"
local mode="$2"
local uid="$3"
local gid="$4"
local ftype=$(filetype "${location}")
# remap uid/gid to 0 if necessary
[ "$root_uid" = "squash" ] && uid=0 || [ "$uid" -eq "$root_uid" ] && uid=0
[ "$root_gid" = "squash" ] && gid=0 || [ "$gid" -eq "$root_gid" ] && gid=0
local str="${mode} ${uid} ${gid}"
[ "${ftype}" == "invalid" ] && return 0
[ "${location}" == "${srcdir}" ] && return 0
case "${ftype}" in
"file")
str="${ftype} ${name} ${location} ${str}"
;;
"nod")
local dev=`LC_ALL=C ls -l "${location}"`
local maj=`field 5 ${dev}`
local min=`field 6 ${dev}`
maj=${maj%,}
[ -b "${location}" ] && dev="b" || dev="c"
str="${ftype} ${name} ${str} ${dev} ${maj} ${min}"
;;
"slink")
local target=`readlink "${location}"`
str="${ftype} ${name} ${target} ${str}"
;;
*)
str="${ftype} ${name} ${str}"
;;
esac
echo "${str}" >> ${output}
return 0
}
unknown_option() {
printf "ERROR: unknown option \"$arg\"\n" >&2
printf "If the filename validly begins with '-', " >&2
printf "then it must be prefixed\n" >&2
printf "by './' so that it won't be interpreted as an option." >&2
printf "\n" >&2
usage >&2
exit 1
}
list_header() {
:
}
header() {
printf "\n#####################\n# $1\n" >> ${output}
}
# process one directory (incl sub-directories)
dir_filelist() {
${dep_list}header "$1"
srcdir=$(echo "$1" | sed -e 's://*:/:g')
dirlist=$(find "${srcdir}" -printf "%p %m %U %G\n")
# If $dirlist is only one line, then the directory is empty
if [ "$(echo "${dirlist}" | wc -l)" -gt 1 ]; then
${dep_list}print_mtime "$1"
echo "${dirlist}" | \
while read x; do
${dep_list}parse ${x}
done
fi
}
# if only one file is specified and it is .cpio file then use it direct as fs
# if a directory is specified then add all files in given direcotry to fs
# if a regular file is specified assume it is in gen_initramfs format
input_file() {
source="$1"
if [ -f "$1" ]; then
${dep_list}header "$1"
is_cpio="$(echo "$1" | sed 's/^.*\.cpio\(\..*\)\?/cpio/')"
if [ $2 -eq 0 -a ${is_cpio} == "cpio" ]; then
cpio_file=$1
echo "$1" | grep -q '^.*\.cpio\..*' && is_cpio_compressed="compressed"
[ ! -z ${dep_list} ] && echo "$1"
return 0
fi
if [ -z ${dep_list} ]; then
print_mtime "$1" >> ${output}
cat "$1" >> ${output}
else
cat "$1" | while read type dir file perm ; do
if [ "$type" == "file" ]; then
echo "$file \\";
fi
done
fi
elif [ -d "$1" ]; then
dir_filelist "$1"
else
echo " ${prog}: Cannot open '$1'" >&2
exit 1
fi
}
prog=$0
root_uid=0
root_gid=0
dep_list=
cpio_file=
cpio_list=
output="/dev/stdout"
output_file=""
is_cpio_compressed=
compr="gzip -9 -f"
arg="$1"
case "$arg" in
"-l") # files included in initramfs - used by kbuild
dep_list="list_"
echo "deps_initramfs := \\"
shift
;;
"-o") # generate compressed cpio image named $1
shift
output_file="$1"
cpio_list="$(mktemp ${TMPDIR:-/tmp}/cpiolist.XXXXXX)"
output=${cpio_list}
echo "$output_file" | grep -q "\.gz$" && compr="gzip -9 -f"
echo "$output_file" | grep -q "\.bz2$" && compr="bzip2 -9 -f"
echo "$output_file" | grep -q "\.lzma$" && compr="lzma -9 -f"
echo "$output_file" | grep -q "\.cpio$" && compr="cat"
shift
;;
esac
while [ $# -gt 0 ]; do
arg="$1"
shift
case "$arg" in
"-u") # map $1 to uid=0 (root)
root_uid="$1"
shift
;;
"-g") # map $1 to gid=0 (root)
root_gid="$1"
shift
;;
"-d") # display default initramfs list
default_list="$arg"
${dep_list}default_initramfs
;;
"-h")
usage
exit 0
;;
*)
case "$arg" in
"-"*)
unknown_option
;;
*) # input file/dir - process it
input_file "$arg" "$#"
;;
esac
;;
esac
done
# If output_file is set we will generate cpio archive and compress it
# we are carefull to delete tmp files
if [ ! -z ${output_file} ]; then
if [ -z ${cpio_file} ]; then
cpio_tfile="$(mktemp ${TMPDIR:-/tmp}/cpiofile.XXXXXX)"
usr/gen_init_cpio ${cpio_list} > ${cpio_tfile}
else
cpio_tfile=${cpio_file}
fi
rm ${cpio_list}
if [ "${is_cpio_compressed}" = "compressed" ]; then
cat ${cpio_tfile} > ${output_file}
else
(cat ${cpio_tfile} | ${compr} - > ${output_file}) \
|| (rm -f ${output_file} ; false)
fi
[ -z ${cpio_file} ] && rm ${cpio_tfile}
fi
exit 0