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authorGravatar Thomas Petazzoni <thomas.petazzoni@bootlin.com>2018-07-04 23:42:57 +0200
committerGravatar Thomas Petazzoni <thomas.petazzoni@bootlin.com>2018-08-21 22:11:51 +0200
commitd67cebcda0edb4ed598c0ed800d0425c4ae14c02 (patch)
treeb233ab8467c10d64970c7fe9dc064135b290d51e /toolchain
parentb1db9038ddaf89c4abf69e17993eb13646da7e8d (diff)
downloadbuildroot-d67cebcda0edb4ed598c0ed800d0425c4ae14c02.tar.gz
buildroot-d67cebcda0edb4ed598c0ed800d0425c4ae14c02.tar.bz2
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 <thomas.petazzoni@bootlin.com> Reviewed-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Diffstat (limited to 'toolchain')
-rw-r--r--toolchain/helpers.mk9
-rw-r--r--toolchain/toolchain-external/pkg-toolchain-external.mk3
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