From ff9f1c5f324eb53adc23bfb80f3c932760c94149 Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Thu, 5 Apr 2012 05:20:37 -0400 Subject: Fix DL_DEBUG_UNUSED to elide the VDSO and handle PLT references properly. * 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. --- elf/dl-lookup.c | 3 ++- elf/rtld.c | 15 ++++++++++++++- 2 files changed, 16 insertions(+), 2 deletions(-) (limited to 'elf') diff --git a/elf/dl-lookup.c b/elf/dl-lookup.c index 839dd3a..a2a699b 100644 --- a/elf/dl-lookup.c +++ b/elf/dl-lookup.c @@ -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 : ""; diff --git a/elf/rtld.c b/elf/rtld.c index 1cc9cf3..0362b14 100644 --- a/elf/rtld.c +++ b/elf/rtld.c @@ -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; -- cgit v1.1