From d67cebcda0edb4ed598c0ed800d0425c4ae14c02 Mon Sep 17 00:00:00 2001 From: Thomas Petazzoni Date: Wed, 4 Jul 2018 23:42:57 +0200 Subject: [PATCH] toolchain: improve musl check to support static toolchains The check_musl function currently builds a program and verifies if the program interpreter starts with /lib/ld-musl. While this works fine for dynamically linked programs, this obviously doesn't work for a purely static musl toolchain such as [1]. There is no easy way to identify a toolchain as using the musl C library. For glibc, dynamic linking is always supported, so we look at the dynamic linker name. For uClibc, there is a distinctive uClibc_config.h header file. There is no such distinctive feature in musl. We end up resorting to looking for the string MUSL_LOCPATH, which is used by musl locale_map.c source file. This string has been present in musl since 2014. It certainly isn't a very stable or convincing solution to identify the C library as being musl, but it's the best we could find. Note that we are sure there is a libc.a file, because the check_unusable_toolchain function checks that there is a such a file. [1] http://autobuild.buildroot.net/toolchains/tarballs/br-arm-musl-static-2018.05.tar.bz2 Signed-off-by: Thomas Petazzoni Reviewed-by: Arnout Vandecappelle (Essensium/Mind) Signed-off-by: Thomas Petazzoni --- toolchain/helpers.mk | 9 +++------ toolchain/toolchain-external/pkg-toolchain-external.mk | 3 +-- 2 files changed, 4 insertions(+), 8 deletions(-) diff --git a/toolchain/helpers.mk b/toolchain/helpers.mk index 1792286add..e5520c00c3 100644 --- a/toolchain/helpers.mk +++ b/toolchain/helpers.mk @@ -241,14 +241,11 @@ check_glibc = \ # $2: cross-readelf path check_musl = \ __CROSS_CC=$(strip $1) ; \ - __CROSS_READELF=$(strip $2) ; \ - echo 'void main(void) {}' | $${__CROSS_CC} -x c -o $(BUILD_DIR)/.br-toolchain-test.tmp - >/dev/null 2>&1; \ - if ! $${__CROSS_READELF} -l $(BUILD_DIR)/.br-toolchain-test.tmp 2> /dev/null | grep 'program interpreter: /lib/ld-musl' -q; then \ - rm -f $(BUILD_DIR)/.br-toolchain-test.tmp*; \ + libc_a_path=`$${__CROSS_CC} -print-file-name=libc.a` ; \ + if ! strings $${libc_a_path} | grep -q MUSL_LOCPATH ; then \ echo "Incorrect selection of the C library" ; \ exit -1; \ - fi ; \ - rm -f $(BUILD_DIR)/.br-toolchain-test.tmp* + fi # # Check the conformity of Buildroot configuration with regard to the diff --git a/toolchain/toolchain-external/pkg-toolchain-external.mk b/toolchain/toolchain-external/pkg-toolchain-external.mk index 8b2c283654..02d992531d 100644 --- a/toolchain/toolchain-external/pkg-toolchain-external.mk +++ b/toolchain/toolchain-external/pkg-toolchain-external.mk @@ -557,8 +557,7 @@ define $(2)_CONFIGURE_CMDS $$(call check_uclibc,$$$${SYSROOT_DIR}) ; \ elif test "$$(BR2_TOOLCHAIN_EXTERNAL_MUSL)" = "y" ; then \ $$(call check_musl,\ - "$$(TOOLCHAIN_EXTERNAL_CC) $$(TOOLCHAIN_EXTERNAL_CFLAGS)",\ - $$(TOOLCHAIN_EXTERNAL_READELF)) ; \ + "$$(TOOLCHAIN_EXTERNAL_CC) $$(TOOLCHAIN_EXTERNAL_CFLAGS)") ; \ else \ $$(call check_glibc,$$$${SYSROOT_DIR}) ; \ fi -- 2.30.2