linux/scripts/gen_initramfs_list.sh

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#!/bin/bash
# Copyright (C) Martin Schlemmer <azarah@nosferatu.za.org>
# Released under the terms of the GNU GPL
#
# Generate a newline separated list of entries from the file/directory
# supplied as an argument.
#
# If a file/directory is not supplied then generate a small dummy file.
#
# The output is suitable for gen_init_cpio built from usr/gen_init_cpio.c.
#
default_initramfs() {
cat <<-EOF
# 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
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
}
print_mtime() {
local argv1="$1"
local my_mtime="0"
if [ -e "${argv1}" ]; then
my_mtime=$(find "${argv1}" -printf "%T@\n" | sort -r | head -n 1)
fi
echo "# Last modified: ${my_mtime}"
echo
}
parse() {
local location="$1"
local name="${location/${srcdir}//}"
# change '//' into '/'
name="${name//\/\///}"
local mode="$2"
local uid="$3"
local gid="$4"
local ftype=$(filetype "${location}")
# remap uid/gid to 0 if necessary
[ "$uid" -eq "$root_uid" ] && uid=0
[ "$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} ${str}"
;;
"nod")
local dev_type=
local maj=$(LC_ALL=C ls -l "${location}" | \
gawk '{sub(/,/, "", $5); print $5}')
local min=$(LC_ALL=C ls -l "${location}" | \
gawk '{print $6}')
if [ -b "${location}" ]; then
dev_type="b"
else
dev_type="c"
fi
str="${ftype} ${name} ${str} ${dev_type} ${maj} ${min}"
;;
"slink")
local target=$(LC_ALL=C ls -l "${location}" | \
gawk '{print $11}')
str="${ftype} ${name} ${target} ${str}"
;;
*)
str="${ftype} ${name} ${str}"
;;
esac
echo "${str}"
return 0
}
usage() {
printf "Usage:\n"
printf "$0 [ [-u <root_uid>] [-g <root_gid>] [-d | <cpio_source>] ] . . .\n"
printf "\n"
printf -- "-u <root_uid> User ID to map to user ID 0 (root).\n"
printf " <root_uid> is only meaningful if <cpio_source>\n"
printf " is a directory.\n"
printf -- "-g <root_gid> Group ID to map to group ID 0 (root).\n"
printf " <root_gid> is only meaningful if <cpio_source>\n"
printf " is a directory.\n"
printf "<cpio_source> File list or directory for cpio archive.\n"
printf " If <cpio_source> is not provided then a\n"
printf " a default list will be output.\n"
printf -- "-d Output the default cpio list. If no <cpio_source>\n"
printf " is given then the default cpio list will be output.\n"
printf "\n"
printf "All options may be repeated and are interpreted sequentially\n"
printf "and immediately. -u and -g states are preserved across\n"
printf "<cpio_source> options so an explicit \"-u 0 -g 0\" is required\n"
printf "to reset the root/group mapping.\n"
}
build_list() {
printf "\n#####################\n# $cpio_source\n"
if [ -f "$cpio_source" ]; then
print_mtime "$cpio_source"
cat "$cpio_source"
elif [ -d "$cpio_source" ]; then
srcdir=$(echo "$cpio_source" | sed -e 's://*:/:g')
dirlist=$(find "${srcdir}" -printf "%p %m %U %G\n" 2>/dev/null)
# If $dirlist is only one line, then the directory is empty
if [ "$(echo "${dirlist}" | wc -l)" -gt 1 ]; then
print_mtime "$cpio_source"
echo "${dirlist}" | \
while read x; do
parse ${x}
done
else
# Failsafe in case directory is empty
default_initramfs
fi
else
echo " $0: Cannot open '$cpio_source'" >&2
exit 1
fi
}
root_uid=0
root_gid=0
while [ $# -gt 0 ]; do
arg="$1"
shift
case "$arg" in
"-u")
root_uid="$1"
shift
;;
"-g")
root_gid="$1"
shift
;;
"-d")
default_list="$arg"
default_initramfs
;;
"-h")
usage
exit 0
;;
*)
case "$arg" in
"-"*)
printf "ERROR: unknown option \"$arg\"\n" >&2
printf "If the filename validly begins with '-', 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
;;
*)
cpio_source="$arg"
build_list
;;
esac
;;
esac
done
# spit out the default cpio list if a source hasn't been specified
[ -z "$cpio_source" -a -z "$default_list" ] && default_initramfs
exit 0