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Fix DL_DEBUG_UNUSED to elide the VDSO and handle PLT references properly.

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* elf/rtld.c (dl_main): If DL_DEBUG_UNUSED is enabled, turn off
	lazy binding.
	* elf/dl-lookup (_dl_lookup_symbol_x): If DL_DEBUG_UNUSED, ignore
	undefined symbol errors.

	* elf/rtlc.c (dl_main): Skip VDSO when checking for unused
	DT_NEEDED entries.
This commit is contained in:
David S. Miller 2012-04-05 05:20:37 -04:00
parent e80d6f94e1
commit ff9f1c5f32
3 changed files with 26 additions and 2 deletions
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10
ChangeLog
View file

@ -1,3 +1,13 @@
2012-04-05 David S. Miller <davem@davemloft.net>
* elf/rtld.c (dl_main): If DL_DEBUG_UNUSED is enabled, turn off
lazy binding.
* elf/dl-lookup (_dl_lookup_symbol_x): If DL_DEBUG_UNUSED, ignore
undefined symbol errors.
* elf/rtlc.c (dl_main): Skip VDSO when checking for unused
DT_NEEDED entries.
2012-04-05 Michael Matz <matz@suse.de>
[BZ #13592]

3
elf/dl-lookup.c
View file

@ -769,7 +769,8 @@ _dl_lookup_symbol_x (const char *undef_name, struct link_map *undef_map,
if (__builtin_expect (current_value.s == NULL, 0))
{
if ((*ref == NULL || ELFW(ST_BIND) ((*ref)->st_info) != STB_WEAK)
&& skip_map == NULL)
&& skip_map == NULL
&& !(GLRO(dl_debug_mask) & DL_DEBUG_UNUSED))
{
/* We could find no value for a strong reference. */
const char *reference_name = undef_map ? undef_map->l_name : "";

15
elf/rtld.c
View file

@ -1967,7 +1967,12 @@ ERROR: ld.so: object '%s' cannot be loaded as audit interface: %s; ignored.\n",
if (dyn->d_tag == DT_NEEDED)
{
l = l->l_next;
#if defined NEED_DL_SYSINFO || defined NEED_DL_SYSINFO_DSO
/* Skip the VDSO since it's not part of the list
of objects we brought in via DT_NEEDED entries. */
if (l == GLRO(dl_sysinfo_map))
l = l->l_next;
#endif
if (!l->l_used)
{
if (first)
@ -2500,6 +2505,14 @@ warning: debug option `%s' unknown; try LD_DEBUG=help\n", copy);
++dl_debug;
}
if (GLRO(dl_debug_mask) & DL_DEBUG_UNUSED)
{
/* In order to get an accurate picture of whether a particular
DT_NEEDED entry is actually used we have to process both
the PLT and non-PLT relocation entries. */
GLRO(dl_lazy) = 0;
}
if (GLRO(dl_debug_mask) & DL_DEBUG_HELP)
{
size_t cnt;