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Don't use IFUNC resolver for longjmp or system in libpthread (bug 21041)

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Unlike the vfork forwarder and like the fork forwarder as in bug 19861,
there won't be a problem when the compiler does not turn this into a tail
call.
This commit is contained in:
Andreas Schwab
2017-08-08 16:21:58 +02:00
parent 852d631207
commit fc5ad7024c
3 changed files with 24 additions and 37 deletions
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24
nptl/pt-system.c
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@ -25,29 +25,21 @@
libpthread, but the historical ABI requires it. For static linking,
there is no need to provide anything here--the libc version will be
linked in. For shared library ABI compatibility, there must be a
'system' symbol in libpthread.so; so we define it using IFUNC to
redirect to the libc function. */
'system' symbol in libpthread.so.
With an IFUNC resolver, it would be possible to avoid the indirection,
but the IFUNC resolver might run before the __libc_system symbol has
been relocated, in which case the IFUNC resolver would not be able to
provide the correct address. */
#if SHLIB_COMPAT (libpthread, GLIBC_2_0, GLIBC_2_22)
# if HAVE_IFUNC
extern __typeof(system) system_ifunc;
# undef INIT_ARCH
# define INIT_ARCH()
libc_ifunc (system_ifunc, &__libc_system)
# else /* !HAVE_IFUNC */
static int __attribute__ ((used))
system_compat (const char *line)
{
return __libc_system (line);
}
strong_alias (system_compat, system_ifunc)
# endif /* HAVE_IFUNC */
compat_symbol (libpthread, system_ifunc, system, GLIBC_2_0);
strong_alias (system_compat, system_alias)
compat_symbol (libpthread, system_alias, system, GLIBC_2_0);
#endif