linux/scripts/mkcompile_h
Masahiro Yamada c8f3dea90e mkcompile_h: use printf for LINUX_COMPILE_BY
Commit 858805b336 ("kbuild: add $(BASH) to run scripts with
bash-extension") shed light on portability issues. Here is another one.

Since commit f07726048d ("Fix handling of backlash character in
LINUX_COMPILE_BY name"), we must escape a backslash contained in
LINUX_COMPILE_BY. This is not working on such distros as Ubuntu.

As the POSIX spec [1] says, if any of the operands contain a backslash
( '\' ) character, the results are implementation-defined.

The actual shell of /bin/sh could be bash, dash, etc. depending on
distros, and the behavior of builtin echo command is different among
them.

The bash builtin echo, unless -e is given, copies the arguments to
stdout without expanding escape sequences (BSD-like behavior).

The dash builtin echo, in contrast, adopts System V behavior, which
does expand escape sequences without any option given.

Even non-builtin /bin/echo behaves differently depending on the system.
Due to these variations, echo is considered as a non-portable command.
Using printf is the common solution to avoid the portability issue.

[1] https://pubs.opengroup.org/onlinepubs/009695399/utilities/echo.html

Fixes: 858805b336 ("kbuild: add $(BASH) to run scripts with bash-extension")
Reported-by: XXing Wei <xxing.wei@unisoc.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2019-12-14 15:53:04 +09:00

97 lines
2.5 KiB
Bash
Executable File

#!/bin/sh
# SPDX-License-Identifier: GPL-2.0
TARGET=$1
ARCH=$2
SMP=$3
PREEMPT=$4
PREEMPT_RT=$5
CC=$6
vecho() { [ "${quiet}" = "silent_" ] || echo "$@" ; }
# If compile.h exists already and we don't own autoconf.h
# (i.e. we're not the same user who did make *config), don't
# modify compile.h
# So "sudo make install" won't change the "compiled by <user>"
# do "compiled by root"
if [ -r $TARGET -a ! -O include/generated/autoconf.h ]; then
vecho " SKIPPED $TARGET"
exit 0
fi
# Do not expand names
set -f
# Fix the language to get consistent output
LC_ALL=C
export LC_ALL
if [ -z "$KBUILD_BUILD_VERSION" ]; then
VERSION=$(cat .version 2>/dev/null || echo 1)
else
VERSION=$KBUILD_BUILD_VERSION
fi
if [ -z "$KBUILD_BUILD_TIMESTAMP" ]; then
TIMESTAMP=`date`
else
TIMESTAMP=$KBUILD_BUILD_TIMESTAMP
fi
if test -z "$KBUILD_BUILD_USER"; then
LINUX_COMPILE_BY=$(whoami | sed 's/\\/\\\\/')
else
LINUX_COMPILE_BY=$KBUILD_BUILD_USER
fi
if test -z "$KBUILD_BUILD_HOST"; then
LINUX_COMPILE_HOST=`hostname`
else
LINUX_COMPILE_HOST=$KBUILD_BUILD_HOST
fi
UTS_VERSION="#$VERSION"
CONFIG_FLAGS=""
if [ -n "$SMP" ] ; then CONFIG_FLAGS="SMP"; fi
if [ -n "$PREEMPT" ] ; then CONFIG_FLAGS="$CONFIG_FLAGS PREEMPT"; fi
if [ -n "$PREEMPT_RT" ] ; then CONFIG_FLAGS="$CONFIG_FLAGS PREEMPT_RT"; fi
# Truncate to maximum length
UTS_LEN=64
UTS_VERSION="$(echo $UTS_VERSION $CONFIG_FLAGS $TIMESTAMP | cut -b -$UTS_LEN)"
# Generate a temporary compile.h
{ echo /\* This file is auto generated, version $VERSION \*/
if [ -n "$CONFIG_FLAGS" ] ; then echo "/* $CONFIG_FLAGS */"; fi
echo \#define UTS_MACHINE \"$ARCH\"
echo \#define UTS_VERSION \"$UTS_VERSION\"
printf '#define LINUX_COMPILE_BY "%s"\n' "$LINUX_COMPILE_BY"
echo \#define LINUX_COMPILE_HOST \"$LINUX_COMPILE_HOST\"
echo \#define LINUX_COMPILER \"`$CC -v 2>&1 | grep ' version ' | sed 's/[[:space:]]*$//'`\"
} > .tmpcompile
# Only replace the real compile.h if the new one is different,
# in order to preserve the timestamp and avoid unnecessary
# recompilations.
# We don't consider the file changed if only the date/time changed.
# A kernel config change will increase the generation number, thus
# causing compile.h to be updated (including date/time) due to the
# changed comment in the
# first line.
if [ -r $TARGET ] && \
grep -v 'UTS_VERSION' $TARGET > .tmpver.1 && \
grep -v 'UTS_VERSION' .tmpcompile > .tmpver.2 && \
cmp -s .tmpver.1 .tmpver.2; then
rm -f .tmpcompile
else
vecho " UPD $TARGET"
mv -f .tmpcompile $TARGET
fi
rm -f .tmpver.1 .tmpver.2