From f289e656ec8221756519a601042bc9fbe1b310fb Mon Sep 17 00:00:00 2001 From: Florian Weimer Date: Fri, 8 Feb 2019 10:21:56 +0100 Subject: [PATCH] rt: Turn forwards from librt to libc into compat symbols [BZ #24194] As the result of commit 6e6249d0b461b952d0f544792372663feb6d792a ("BZ#14743: Move clock_* symbols from librt to libc."), in glibc 2.17, clock_gettime, clock_getres, clock_settime, clock_getcpuclockid, clock_nanosleep were added to libc, and the file rt/clock-compat.c was added with forwarders to the actual implementations in libc. These forwarders were wrapped in #if SHLIB_COMPAT (librt, GLIBC_2_2, GLIBC_2_17) so that they are not present for newer architectures (such as powerpc64le) with a 2.17 or later ABI baseline. But the forwarders were not marked as compatibility symbols. As a result, on older architectures, historic configure checks such as AC_CHECK_LIB(rt, clock_gettime) still cause linking against librt, even though this is completely unnecessary. It also creates a needless porting hazard because architectures behave differently when it comes to symbol availability. Reviewed-by: Carlos O'Donell --- ChangeLog | 5 +++++ NEWS | 6 +++++- rt/clock-compat.c | 6 ++++-- 3 files changed, 14 insertions(+), 3 deletions(-) diff --git a/ChangeLog b/ChangeLog index 29f4ac31e1..20ff76ab62 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,8 @@ +2019-02-07 Florian Weimer + + * rt/clock-compat.c (COMPAT_REDIRECT): Turn librt forwarders into + compatibility symbols. + 2019-02-07 Stefan Liebler [BZ #24180] diff --git a/NEWS b/NEWS index e14008d7ad..45792f62a9 100644 --- a/NEWS +++ b/NEWS @@ -14,7 +14,11 @@ Major new features: Deprecated and removed features, and other changes affecting compatibility: - [Add deprecations, removals and changes affecting compatibility here] +* The functions clock_gettime, clock_getres, clock_settime, + clock_getcpuclockid, clock_nanosleep were removed from the librt library + for new applications (on architectures which had them). Instead, the + definitions in libc will be used automatically, which have been available + since glibc 2.17. Changes to build and runtime requirements: diff --git a/rt/clock-compat.c b/rt/clock-compat.c index c603f40b69..d8ced3cdc1 100644 --- a/rt/clock-compat.c +++ b/rt/clock-compat.c @@ -30,14 +30,16 @@ #if HAVE_IFUNC # undef INIT_ARCH # define INIT_ARCH() -# define COMPAT_REDIRECT(name, proto, arglist) libc_ifunc (name, &__##name) +# define COMPAT_REDIRECT(name, proto, arglist) libc_ifunc (name, &__##name) \ + compat_symbol (librt, name, name, GLIBC_2_2); #else # define COMPAT_REDIRECT(name, proto, arglist) \ int \ name proto \ { \ return __##name arglist; \ - } + } \ + compat_symbol (librt, name, name, GLIBC_2_2); #endif COMPAT_REDIRECT (clock_getres,