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[Bug libc/2765] New: malloc.c strong_alias for free, malloc, realloc should be weak_alias
- From: "mbland at google dot com" <sourceware-bugzilla at sourceware dot org>
- To: glibc-bugs at sources dot redhat dot com
- Date: 14 Jun 2006 07:52:42 -0000
- Subject: [Bug libc/2765] New: malloc.c strong_alias for free, malloc, realloc should be weak_alias
- Reply-to: sourceware-bugzilla at sourceware dot org
Building a static libc using 2.3.5 causes symbols from malloc.c (namely free,
malloc, and realloc) to be exported as non-weak due to the use of strong_alias.
This causes problems when trying to interpose these functions during a static
link with definitions from another object. For example:
mbland:~/test/static_interpose$ cat > foo.c
#include <stddef.h>
void *
malloc (size_t unused)
{
return 0;
}
int
main (void)
{
(void) malloc (0);
return 0;
}
mbland:~/test/static_interpose$ gcc foo.c
mbland:~/test/static_interpose$ gcc -static foo.c
/usr/lib/gcc/i486-linux-gnu/4.0.2/../../../../lib/libc.a(malloc.o): In function
`malloc':
: multiple definition of `malloc'
/tmp/ccCJFGaW.o:foo.c:(.text+0x0): first defined here
/usr/bin/ld: Warning: size of symbol `malloc' changed from 10 in /tmp/ccCJFGaW.o
to 397 in /usr/lib/gcc/i486-linux-gnu/4.0.2/../../../../lib/libc.a(malloc.o)
collect2: ld returned 1 exit status
This example works in both cases with glibc-2.3.2, as these symbols were defined
as weak in the 2.3.2 libc.a. Though I'm currently using glibc-2.3.5, I've
noticed that the strong_alias instances still persist in the current CVS.
I've built a static glibc with all the strong_alias instances changed to
weak_alias, and successfully built a statically-linked executable with these
symbols interposed.
--- glibc-2.3.5-orig/malloc/malloc.c 2006-06-13 13:49:00.000000000 -0700
+++ glibc-2.3.5/malloc/malloc.c 2006-06-13 15:35:20.000000000 -0700
@@ -5566,11 +5566,11 @@ weak_alias (__posix_memalign, posix_mema
strong_alias (__libc_calloc, __calloc) weak_alias (__libc_calloc, calloc)
strong_alias (__libc_free, __cfree) weak_alias (__libc_free, cfree)
-strong_alias (__libc_free, __free) strong_alias (__libc_free, free)
-strong_alias (__libc_malloc, __malloc) strong_alias (__libc_malloc, malloc)
+strong_alias (__libc_free, __free) weak_alias (__libc_free, free)
+strong_alias (__libc_malloc, __malloc) weak_alias (__libc_malloc, malloc)
strong_alias (__libc_memalign, __memalign)
weak_alias (__libc_memalign, memalign)
-strong_alias (__libc_realloc, __realloc) strong_alias (__libc_realloc, realloc)
+strong_alias (__libc_realloc, __realloc) weak_alias (__libc_realloc, realloc)
strong_alias (__libc_valloc, __valloc) weak_alias (__libc_valloc, valloc)
strong_alias (__libc_pvalloc, __pvalloc) weak_alias (__libc_pvalloc, pvalloc)
strong_alias (__libc_mallinfo, __mallinfo)
--
Summary: malloc.c strong_alias for free, malloc, realloc should
be weak_alias
Product: glibc
Version: 2.3.5
Status: NEW
Severity: normal
Priority: P2
Component: libc
AssignedTo: drepper at redhat dot com
ReportedBy: mbland at google dot com
CC: glibc-bugs at sources dot redhat dot com,mec at google
dot com
GCC build triplet: i486-linux-gnu
GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i486-linux-gnu
http://sourceware.org/bugzilla/show_bug.cgi?id=2765
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