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| author | Joseph Myers <joseph@codesourcery.com> | 2014-11-12 22:36:34 +0000 |
|---|---|---|
| committer | Joseph Myers <joseph@codesourcery.com> | 2014-11-12 22:36:34 +0000 |
| commit | 939da41143341bbcdd3dd50ee7b57776603da260 (patch) | |
| tree | d5dc07d8ed641dd9411608554206455070679098 | |
| parent | 293d9a41805b1eeb440a2c59a717b332cd9c2384 (diff) | |
| download | glibc-939da41143341bbcdd3dd50ee7b57776603da260.tar.gz glibc-939da41143341bbcdd3dd50ee7b57776603da260.tar.xz glibc-939da41143341bbcdd3dd50ee7b57776603da260.zip | |
Fix stpcpy / mempcpy namespace (bug 17573).
Various glibc functions call __stpcpy and __mempcpy for namespace reasons instead of plain stpcpy and mempcpy. But __stpcpy and __mempcpy are macros that call __builtin_stpcpy and __builtin_mempcpy, and unless GCC optimizes the calls, they end up calling the C functions stpcpy and mempcpy. For calls from within shared libc, libc_hidden_builtin_proto ensures that calls to those C functions are in turn mapped to call __GI_stpcpy and __GI_mempcpy. However, for static libc, and for calls from shared libraries other than libc, the ELF symbols stpcpy and mempcpy end up getting called, breaking the ISO C namespace (in the case of stpcpy) or glibc conventions about not relying on the "future library directions" reservations (in the case of mempcpy). This patch fixes this by adding declarations of these functions to include/string.h, under an appropriate condition, with __asm__ used to change the assembler name used for calls (the mempcpy case was previously discussed, and the approach for the fix is as I suggested in <https://sourceware.org/ml/libc-alpha/2013-02/msg00063.html>). Tested for x86_64 with the testsuite; also checked that dcigettext.o (an example previously noted of undesired calls to stpcpy and mempcpy) now calls __stpcpy and __mempcpy instead, as do non-libc shared libraries (__stpcpy and __mempcpy were already exported from shared libc). Disassembly of installed shared libraries isn't easy to compare because of reordered PLT entries resulting from the change in functions called (libnsl, libnss_compat, libnss_dns, libnss_files, libnss_hesiod, libnss_nis, libnss_nisplus, libpthread, librt all have such changes). [BZ #17573] * include/string.h [NOT_IN_libc || !SHARED] (mempcpy): Declare with asm name __mempcpy. [NOT_IN_libc || !SHARED] (stpcpy): Declare with asm name __stpcpy.
| -rw-r--r-- | ChangeLog | 5 | ||||
| -rw-r--r-- | NEWS | 2 | ||||
| -rw-r--r-- | include/string.h | 7 |
3 files changed, 13 insertions, 1 deletions
diff --git a/ChangeLog b/ChangeLog index 1a798b54ea..f33d5828f0 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,5 +1,10 @@ 2014-11-12 Joseph Myers <joseph@codesourcery.com> + [BZ #17573] + * include/string.h [NOT_IN_libc || !SHARED] (mempcpy): Declare + with asm name __mempcpy. + [NOT_IN_libc || !SHARED] (stpcpy): Declare with asm name __stpcpy. + [BZ #17572] * sysdeps/x86_64/rawmemchr.S (rawmemchr): Rename to __rawmemchr and define as weak alias of __rawmemchr. diff --git a/NEWS b/NEWS index e94ba06d83..befd5e59c7 100644 --- a/NEWS +++ b/NEWS @@ -11,7 +11,7 @@ Version 2.21 6652, 12926, 14132, 14138, 14171, 15215, 15884, 17266, 17344, 17363, 17370, 17371, 17411, 17460, 17475, 17485, 17501, 17506, 17508, 17522, - 17555, 17570, 17571, 17572, 17583, 17584. + 17555, 17570, 17571, 17572, 17573, 17583, 17584. * New locales: tu_IN, bh_IN. diff --git a/include/string.h b/include/string.h index 8323412240..2603e9c0ab 100644 --- a/include/string.h +++ b/include/string.h @@ -113,6 +113,13 @@ libc_hidden_builtin_proto (strspn) libc_hidden_builtin_proto (strstr) libc_hidden_builtin_proto (ffs) +#if defined NOT_IN_libc || !defined SHARED +/* Redirect calls to __builtin_mempcpy and __builtin_stpcpy to call + __mempcpy and __stpcpy if not inlined. */ +extern __typeof (mempcpy) mempcpy __asm__ ("__mempcpy"); +extern __typeof (stpcpy) stpcpy __asm__ ("__stpcpy"); +#endif + # ifndef _ISOMAC # ifndef index # define index(s, c) (strchr ((s), (c))) |