diff options
| -rw-r--r-- | ChangeLog | 14 | ||||
| -rw-r--r-- | elf/dl-lookup.c | 33 | ||||
| -rw-r--r-- | elf/dl-runtime.c | 36 | ||||
| -rw-r--r-- | elf/dl-sym.c | 4 | ||||
| -rw-r--r-- | sysdeps/generic/ldsodefs.h | 8 |
5 files changed, 68 insertions, 27 deletions
diff --git a/ChangeLog b/ChangeLog index fff37d557f..5d60391f85 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,17 @@ +2007-01-15 Ulrich Drepper <drepper@redhat.com> + + * sysdeps/generic/ldsodefs.h: Define DL_LOOKUP_SCOPE_LOCK. + * elf/dl-lookup.c (add_dependency): If scope map is locked, unlock + it before getting dl_load_lock and then relock. + (_dl_lookup_symbol_x): Pass flags to add_dependency. + When rerunning _dl_lookup_symbol_x, compute symbol_scope again in + case we unlocked the scope. + * elf/dl-runtime.c (_dl_fixup): Pass DL_LOOKUP_SCOPE_LOCK to + _dl_lookup_symbol_x in case we locked the scope. + (_dl_profile_fixup): Likewise. + * elf/dl-sym.c (do_sym): In flags passed to call_dl_lookup, also + set DL_LOOKUP_SCOPE_LOCK. + 2007-01-13 Ulrich Drepper <drepper@redhat.com> * inet/Makefile: Define CFLAGS-getsrvbynm_r.c and diff --git a/elf/dl-lookup.c b/elf/dl-lookup.c index 019278c9b0..a6a958419f 100644 --- a/elf/dl-lookup.c +++ b/elf/dl-lookup.c @@ -1,5 +1,5 @@ /* Look up a symbol in the loaded objects. - Copyright (C) 1995-2005, 2006 Free Software Foundation, Inc. + Copyright (C) 1995-2005, 2006, 2007 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or @@ -25,6 +25,7 @@ #include <ldsodefs.h> #include <dl-hash.h> #include <dl-machine.h> +#include <sysdep-cancel.h> #include <bits/libc-lock.h> #include <tls.h> @@ -85,7 +86,7 @@ dl_new_hash (const char *s) /* Add extra dependency on MAP to UNDEF_MAP. */ static int internal_function -add_dependency (struct link_map *undef_map, struct link_map *map) +add_dependency (struct link_map *undef_map, struct link_map *map, int flags) { struct link_map **list; struct link_map *runp; @@ -98,8 +99,18 @@ add_dependency (struct link_map *undef_map, struct link_map *map) if (undef_map == map) return 0; - /* Make sure nobody can unload the object while we are at it. */ - __rtld_lock_lock_recursive (GL(dl_load_lock)); + /* Make sure nobody can unload the object while we are at it. + If we hold a scope lock drop it now to avoid ABBA locking problems. */ + if ((flags & DL_LOOKUP_SCOPE_LOCK) != 0 && !RTLD_SINGLE_THREAD_P) + { + __rtld_mrlock_unlock (undef_map->l_scope_lock); + + __rtld_lock_lock_recursive (GL(dl_load_lock)); + + __rtld_mrlock_lock (undef_map->l_scope_lock); + } + else + __rtld_lock_lock_recursive (GL(dl_load_lock)); /* Avoid references to objects which cannot be unloaded anyway. */ if (map->l_type != lt_loaded @@ -226,9 +237,10 @@ _dl_lookup_symbol_x (const char *undef_name, struct link_map *undef_map, bump_num_relocations (); - /* No other flag than DL_LOOKUP_ADD_DEPENDENCY is allowed if we look - up a versioned symbol. */ - assert (version == NULL || flags == 0 || flags == DL_LOOKUP_ADD_DEPENDENCY); + /* No other flag than DL_LOOKUP_ADD_DEPENDENCY and DL_LOOKUP_SCOPE_LOCK + is allowed if we look up a versioned symbol. */ + assert (version == NULL || (flags & ~(DL_LOOKUP_ADD_DEPENDENCY + | DL_LOOKUP_SCOPE_LOCK)) == 0); size_t i = 0; if (__builtin_expect (skip_map != NULL, 0)) @@ -338,12 +350,13 @@ _dl_lookup_symbol_x (const char *undef_name, struct link_map *undef_map, runtime lookups. */ && (flags & DL_LOOKUP_ADD_DEPENDENCY) != 0 /* Add UNDEF_MAP to the dependencies. */ - && add_dependency (undef_map, current_value.m) < 0) + && add_dependency (undef_map, current_value.m, flags) < 0) /* Something went wrong. Perhaps the object we tried to reference was just removed. Try finding another definition. */ return _dl_lookup_symbol_x (undef_name, undef_map, ref, - symbol_scope, version, type_class, - flags, skip_map); + (flags & DL_LOOKUP_SCOPE_LOCK) == 0 + ? symbol_scope : undef_map->l_scope, version, + type_class, flags, skip_map); /* The object is used. */ current_value.m->l_used = 1; diff --git a/elf/dl-runtime.c b/elf/dl-runtime.c index afc99f6150..9ecf62b436 100644 --- a/elf/dl-runtime.c +++ b/elf/dl-runtime.c @@ -1,5 +1,5 @@ /* On-demand PLT fixup for shared objects. - Copyright (C) 1995-2002,2003,2004,2005,2006 Free Software Foundation, Inc. + Copyright (C) 1995-2006, 2007 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or @@ -93,14 +93,20 @@ _dl_fixup ( version = NULL; } + /* We need to keep the scope around so do some locking. This is + not necessary for objects which cannot be unloaded or when + we are not using any threads (yet). */ + int flags = DL_LOOKUP_ADD_DEPENDENCY; if (l->l_type == lt_loaded && !RTLD_SINGLE_THREAD_P) - __rtld_mrlock_lock (l->l_scope_lock); + { + __rtld_mrlock_lock (l->l_scope_lock); + flags |= DL_LOOKUP_SCOPE_LOCK; + } - result = _dl_lookup_symbol_x (strtab + sym->st_name, l, &sym, - l->l_scope, version, ELF_RTYPE_CLASS_PLT, - DL_LOOKUP_ADD_DEPENDENCY, NULL); + result = _dl_lookup_symbol_x (strtab + sym->st_name, l, &sym, l->l_scope, + version, ELF_RTYPE_CLASS_PLT, flags, NULL); - if (l->l_type == lt_loaded && !RTLD_SINGLE_THREAD_P) + if ((flags & DL_LOOKUP_SCOPE_LOCK) != 0) __rtld_mrlock_unlock (l->l_scope_lock); /* Currently result contains the base load address (or link map) @@ -181,15 +187,21 @@ _dl_profile_fixup ( version = NULL; } + /* We need to keep the scope around so do some locking. This is + not necessary for objects which cannot be unloaded or when + we are not using any threads (yet). */ + int flags = DL_LOOKUP_ADD_DEPENDENCY; if (l->l_type == lt_loaded && !RTLD_SINGLE_THREAD_P) - __rtld_mrlock_lock (l->l_scope_lock); + { + __rtld_mrlock_lock (l->l_scope_lock); + flags |= DL_LOOKUP_SCOPE_LOCK; + } - result = _dl_lookup_symbol_x (strtab + refsym->st_name, l, &defsym, - l->l_scope, version, - ELF_RTYPE_CLASS_PLT, - DL_LOOKUP_ADD_DEPENDENCY, NULL); + result = _dl_lookup_symbol_x (strtab + refsym->st_name, l, + &defsym, l->l_scope, version, + ELF_RTYPE_CLASS_PLT, flags, NULL); - if (l->l_type == lt_loaded && !RTLD_SINGLE_THREAD_P) + if ((flags & DL_LOOKUP_SCOPE_LOCK) != 0) __rtld_mrlock_unlock (l->l_scope_lock); /* Currently result contains the base load address (or link map) diff --git a/elf/dl-sym.c b/elf/dl-sym.c index 88a5adb0d5..1c3ab5c877 100644 --- a/elf/dl-sym.c +++ b/elf/dl-sym.c @@ -1,5 +1,5 @@ /* Look up a symbol in a shared object loaded by `dlopen'. - Copyright (C) 1999,2000,2001,2002,2004,2006 Free Software Foundation, Inc. + Copyright (C) 1999-2002,2004,2006,2007 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or @@ -126,7 +126,7 @@ do_sym (void *handle, const char *name, void *who, args.name = name; args.map = match; args.vers = vers; - args.flags = flags | DL_LOOKUP_ADD_DEPENDENCY; + args.flags = flags | DL_LOOKUP_ADD_DEPENDENCY | DL_LOOKUP_SCOPE_LOCK; args.refp = &ref; const char *objname; diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h index dda91bb806..a9d20b2150 100644 --- a/sysdeps/generic/ldsodefs.h +++ b/sysdeps/generic/ldsodefs.h @@ -1,5 +1,5 @@ /* Run-time dynamic linker data structures for loaded ELF shared objects. - Copyright (C) 1995-2003, 2004, 2005, 2006 Free Software Foundation, Inc. + Copyright (C) 1995-2006, 2007 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or @@ -838,7 +838,9 @@ enum DL_LOOKUP_ADD_DEPENDENCY = 1, /* Return most recent version instead of default version for unversioned lookup. */ - DL_LOOKUP_RETURN_NEWEST = 2 + DL_LOOKUP_RETURN_NEWEST = 2, + /* Set if the scopr lock in the UNDEF_MAP is taken. */ + DL_LOOKUP_SCOPE_LOCK = 4 }; /* Lookup versioned symbol. */ @@ -847,7 +849,7 @@ extern lookup_t _dl_lookup_symbol_x (const char *undef, const ElfW(Sym) **sym, struct r_scope_elem *symbol_scope[], const struct r_found_version *version, - int type_class, int explicit, + int type_class, int flags, struct link_map *skip_map) internal_function attribute_hidden; |