The build id generated from --build-id can be generated in several different ways, with the default being the sha1 on the output of the linked file. For distributions, it can be useful to make sure this ID is unique, even if the actual file contents don't change. The easiest way to do this is to insert a comment section with some data.
Introduce a header which is generated from an environment varible, BUILD_TAG. If this variable is set, an appropriate .comment section is generated. If the environment variable isn't set, the define is simply empty and there is no change to the build. Suggested-by: Nick Clifton <[email protected]> Signed-off-by: Laura Abbott <[email protected]> --- Makefile | 9 ++++++++- scripts/gencomment | 19 +++++++++++++++++++ 2 files changed, 27 insertions(+), 1 deletion(-) create mode 100755 scripts/gencomment diff --git a/Makefile b/Makefile index d65e2e229017..de360625aec5 100644 --- a/Makefile +++ b/Makefile @@ -1087,7 +1087,7 @@ endif prepare2: prepare3 prepare-compiler-check outputmakefile asm-generic prepare1: prepare2 $(version_h) include/generated/utsrelease.h \ - include/config/auto.conf + include/config/auto.conf include/generated/build-salt.h $(cmd_crmodverdir) archprepare: archheaders archscripts prepare1 scripts_basic @@ -1175,6 +1175,13 @@ $(version_h): $(srctree)/Makefile FORCE include/generated/utsrelease.h: include/config/kernel.release FORCE $(call filechk,utsrelease.h) +define filechk_build-salt.h + ($(CONFIG_SHELL) $(srctree)/scripts/gencomment) +endef + +include/generated/build-salt.h: $(srctree)/Makefile FORCE + $(call filechk,build-salt.h) + PHONY += headerdep headerdep: $(Q)find $(srctree)/include/ -name '*.h' | xargs --max-args 1 \ diff --git a/scripts/gencomment b/scripts/gencomment new file mode 100755 index 000000000000..13b6e7739ef7 --- /dev/null +++ b/scripts/gencomment @@ -0,0 +1,19 @@ +#!/bin/sh + +if [ -z $BUILD_TAG ]; then + echo "#define ID_TAG" + exit 0 +fi + +echo "#define ID_TAG \\" +echo ".comment (INFO) : \\" +echo " { \\" + +_TAG=`echo $BUILD_TAG | sed -e 's/\(.\)/\1 /g'` +for c in $_TAG; do + _HEX=`echo -n $c | od -A n -t x1 | tr -d ' ' ` + echo "BYTE(0x$_HEX); \\" +done +echo "BYTE(0x00); \\" + +echo " } " -- 2.16.2
