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405544d5f8
[ Upstream commit 825d487583 ]
Some filesystems have timestamps with coarse precision that may allow
for a recently built object file to have the same timestamp as the
updated time on one of its dependency files. When that happens, the
object file doesn't get rebuilt as it should.
This is especially the case on filesystems that don't have sub-second
time precision, such as ext3 or Ext4 with 128B inodes.
Let's prevent that by making sure updated dependency files have a newer
timestamp than the first file we created (i.e. autoksyms.h.tmpnew).
Reported-by: Thomas Lindroth <thomas.lindroth@gmail.com>
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Tested-by: Thomas Lindroth <thomas.lindroth@gmail.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
110 lines
3.1 KiB
Bash
Executable File
110 lines
3.1 KiB
Bash
Executable File
#!/bin/sh
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# Script to create/update include/generated/autoksyms.h and dependency files
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#
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# Copyright: (C) 2016 Linaro Limited
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# Created by: Nicolas Pitre, January 2016
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License version 2 as
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# published by the Free Software Foundation.
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# Create/update the include/generated/autoksyms.h file from the list
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# of all module's needed symbols as recorded on the third line of
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# .tmp_versions/*.mod files.
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#
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# For each symbol being added or removed, the corresponding dependency
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# file's timestamp is updated to force a rebuild of the affected source
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# file. All arguments passed to this script are assumed to be a command
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# to be exec'd to trigger a rebuild of those files.
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set -e
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cur_ksyms_file="include/generated/autoksyms.h"
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new_ksyms_file="include/generated/autoksyms.h.tmpnew"
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info() {
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if [ "$quiet" != "silent_" ]; then
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printf " %-7s %s\n" "$1" "$2"
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fi
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}
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info "CHK" "$cur_ksyms_file"
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# Use "make V=1" to debug this script.
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case "$KBUILD_VERBOSE" in
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*1*)
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set -x
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;;
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esac
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# We need access to CONFIG_ symbols
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case "${KCONFIG_CONFIG}" in
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*/*)
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. "${KCONFIG_CONFIG}"
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;;
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*)
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# Force using a file from the current directory
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. "./${KCONFIG_CONFIG}"
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esac
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# In case it doesn't exist yet...
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if [ -e "$cur_ksyms_file" ]; then touch "$cur_ksyms_file"; fi
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# Generate a new ksym list file with symbols needed by the current
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# set of modules.
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cat > "$new_ksyms_file" << EOT
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/*
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* Automatically generated file; DO NOT EDIT.
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*/
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EOT
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[ "$(ls -A "$MODVERDIR")" ] &&
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sed -ns -e '3{s/ /\n/g;/^$/!p;}' "$MODVERDIR"/*.mod | sort -u |
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while read sym; do
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if [ -n "$CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX" ]; then
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sym="${sym#_}"
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fi
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echo "#define __KSYM_${sym} 1"
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done >> "$new_ksyms_file"
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# Special case for modversions (see modpost.c)
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if [ -n "$CONFIG_MODVERSIONS" ]; then
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echo "#define __KSYM_module_layout 1" >> "$new_ksyms_file"
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fi
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# Extract changes between old and new list and touch corresponding
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# dependency files.
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changed=$(
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count=0
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sort "$cur_ksyms_file" "$new_ksyms_file" | uniq -u |
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sed -n 's/^#define __KSYM_\(.*\) 1/\1/p' | tr "A-Z_" "a-z/" |
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while read sympath; do
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if [ -z "$sympath" ]; then continue; fi
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depfile="include/config/ksym/${sympath}.h"
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mkdir -p "$(dirname "$depfile")"
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touch "$depfile"
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# Filesystems with coarse time precision may create timestamps
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# equal to the one from a file that was very recently built and that
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# needs to be rebuild. Let's guard against that by making sure our
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# dep files are always newer than the first file we created here.
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while [ ! "$depfile" -nt "$new_ksyms_file" ]; do
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touch "$depfile"
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done
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echo $((count += 1))
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done | tail -1 )
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changed=${changed:-0}
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if [ $changed -gt 0 ]; then
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# Replace the old list with tne new one
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old=$(grep -c "^#define __KSYM_" "$cur_ksyms_file" || true)
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new=$(grep -c "^#define __KSYM_" "$new_ksyms_file" || true)
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info "KSYMS" "symbols: before=$old, after=$new, changed=$changed"
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info "UPD" "$cur_ksyms_file"
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mv -f "$new_ksyms_file" "$cur_ksyms_file"
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# Then trigger a rebuild of affected source files
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exec $@
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else
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rm -f "$new_ksyms_file"
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fi
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