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authorFrédéric Bérat <fberat@redhat.com>2023-04-26 17:26:51 +0200
committerFrédéric Bérat <fberat@redhat.com>2023-07-05 16:59:48 +0200
commit505c884aeb059ee7741c23d1bfc47956bd9c2a0e (patch)
tree447deafa691b2ed964b49e4f7d85843a4e16a540 /debug/sprintf_chk.c
parentdd8486ffc195f5fe150b2d3724c7712686cfddb0 (diff)
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stdio: Ensure *_chk routines have their hidden builtin definition available
If libc_hidden_builtin_{def,proto} isn't properly set for *_chk routines,
there are unwanted PLT entries in libc.so.

There is a special case with __asprintf_chk:
If ldbl_* macros are used for asprintf, ABI gets broken on s390x,
if it isn't, ppc64le isn't building due to multiple asm redirections.

This is due to the inclusion of bits/stdio-lbdl.h for ppc64le whereas it
isn't for s390x. This header creates redirections, which are not
compatible with the ones generated using libc_hidden_def.
Yet, we can't use libc_hidden_ldbl_proto on s390x since it will not
create a simple strong alias (e.g. as done on x86_64), but a versioned
alias, leading to ABI breakage.

This results in errors on s390x:
/usr/bin/ld: glibc/iconv/../libio/bits/stdio2.h:137: undefined reference
to `__asprintf_chk'

Original __asprintf_chk symbols:
00000000001395b0 T __asprintf_chk
0000000000177e90 T __nldbl___asprintf_chk

__asprintf_chk symbols with ldbl_* macros:
000000000012d590 t ___asprintf_chk
000000000012d590 t __asprintf_chk@@GLIBC_2.4
000000000012d590 t __GI___asprintf_chk
000000000012d590 t __GL____asprintf_chk___asprintf_chk
0000000000172240 T __nldbl___asprintf_chk

__asprintf_chk symbols with the patch:
000000000012d590 t ___asprintf_chk
000000000012d590 T __asprintf_chk
000000000012d590 t __GI___asprintf_chk
0000000000172240 T __nldbl___asprintf_chk

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Diffstat (limited to 'debug/sprintf_chk.c')
-rw-r--r--debug/sprintf_chk.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/debug/sprintf_chk.c b/debug/sprintf_chk.c
index b27f4afae8..e45f1e7b3b 100644
--- a/debug/sprintf_chk.c
+++ b/debug/sprintf_chk.c
@@ -42,4 +42,5 @@ ___sprintf_chk (char *s, int flag, size_t slen, const char *format, ...)
 
   return ret;
 }
+ldbl_hidden_def (___sprintf_chk, __sprintf_chk)
 ldbl_strong_alias (___sprintf_chk, __sprintf_chk)