Create the init.c as a temporary init-tmp.c file, even if init already exists. Ensure the existing init.c matches this. If init.c doesn't exist in initrd/ then skip the check and assume init-tmp.c as the new init.c. After that, check if init binary already exists as we did before and skip the build if it does.
This does mean we keep a copy of init.c around in the initrd but this is a small file and it is useful to see for debugging anyway.
Signed-off-by: Joel Fernandes (Google) joel@joelfernandes.org --- .../selftests/rcutorture/bin/mkinitrd.sh | 34 +++++++++++++------ 1 file changed, 24 insertions(+), 10 deletions(-)
diff --git a/tools/testing/selftests/rcutorture/bin/mkinitrd.sh b/tools/testing/selftests/rcutorture/bin/mkinitrd.sh index 4ba5e962e3cf..d9fbfa205384 100755 --- a/tools/testing/selftests/rcutorture/bin/mkinitrd.sh +++ b/tools/testing/selftests/rcutorture/bin/mkinitrd.sh @@ -17,10 +17,6 @@ if [ ! -d "$D" ]; then echo >&2 "$D does not exist: Malformed kernel source tree?" exit 1 fi -if [ -s "$D/initrd/init" ]; then - echo "$D/initrd/init already exists, no need to create it" - exit 0 -fi
# Create a C-language initrd/init infinite-loop program and statically # link it. This results in a very small initrd. @@ -29,8 +25,10 @@ cd $D mkdir -p initrd cd initrd
-# Generate the init.c with optional command -cat > init.c << 'EOF_HEAD' +# Generate an init-tmp.c with optional command. This will then be compared +# with any existing init.c. The reason for this is, we want to force a +# rebuild if the optional command or command line arguments have changed. +cat > init-tmp.c << 'EOF_HEAD' #ifndef NOLIBC #include <unistd.h> #include <sys/time.h> @@ -45,7 +43,7 @@ if [ $# -gt 0 ]; then # If command provided, generate run_optional_command() with the specified command. # We use printf to generate the command and args. # Example: echo $(printf '"%s", ' cmd a1 a2) gives: "cmd", "a1", "a2", - cat >> init.c << EOF + cat >> init-tmp.c << EOF pid_t pid = fork(); if (pid == 0) { char *args[] = {$(printf '"%s", ' "$@")NULL}; @@ -54,11 +52,11 @@ if [ $# -gt 0 ]; then EOF else # If no command provided, function will be empty - echo " /* No command specified */" >> init.c + echo " /* No command specified */" >> init-tmp.c fi
# Add the rest of the program -cat >> init.c << 'EOF_TAIL' +cat >> init-tmp.c << 'EOF_TAIL' }
int main(int argc, char *argv[]) @@ -95,6 +93,23 @@ int main(int argc, char *argv[]) } EOF_TAIL
+# Check if init.c exists and compare with init-tmp.c +if [ -f "init.c" ]; then + if ! cmp -s "init.c" "init-tmp.c"; then + mv "init-tmp.c" "init.c" + else + rm "init-tmp.c" + fi +else + mv "init-tmp.c" "init.c" +fi + +# Now check if init binary exists and is up to date +if [ -s "init" ] && [ "init" -nt "init.c" ]; then + echo "$D/initrd/init already exists and is up to date" + exit 0 +fi + # build using nolibc on supported archs (smaller executable) and fall # back to regular glibc on other ones. if echo -e "#if __x86_64__||__i386__||__i486__||__i586__||__i686__" \ @@ -120,7 +135,6 @@ then exit "$ret" fi
-rm init.c echo "Done creating a statically linked C-language initrd"
exit 0