commit 6ee65ed6ddbf04402fad0bec6aa9c73b9d982ae4 Author: Ulrich Drepper Date: Fri Jan 27 15:05:19 2012 -0500 Sort objects before relocations 2012-01-27 Ulrich Drepper [BZ #13618] * elf/dl-open.c (dl_open_worker): Sort objects by dependency before relocation. * Makeconfig (libm): Define. * elf/Makefile: Add rules to build and run tst-relsort1. * elf/tst-relsort1.c: New file. * elf/tst-relsort1mod1.c: New file. * elf/tst-relsort1mod2.c: New file. Index: glibc-2.15/Makeconfig =================================================================== --- glibc-2.15.orig/Makeconfig +++ glibc-2.15/Makeconfig @@ -950,6 +950,12 @@ libdl = endif endif +ifeq ($(build-shared),yes) +libm = $(common-objpfx)math/libm.so$(libm.so-version) +else +libm = $(common-objpfx)math/libm.a +endif + # These are the subdirectories containing the library source. The order # is more or less arbitrary. The sorting step will take care of the # dependencies. Index: glibc-2.15/elf/Makefile =================================================================== --- glibc-2.15.orig/elf/Makefile +++ glibc-2.15/elf/Makefile @@ -124,7 +124,8 @@ distribute := rtld-Rules \ tst-initordera1.c tst-initordera2.c tst-initorderb1.c \ tst-initorderb2.c tst-initordera3.c tst-initordera4.c \ tst-initorder.c \ - tst-initorder2.c + tst-initorder2.c \ + tst-relsort1.c tst-relsort1mod1.c tst-relsort1mod2.c CFLAGS-dl-runtime.c = -fexceptions -fasynchronous-unwind-tables CFLAGS-dl-lookup.c = -fexceptions -fasynchronous-unwind-tables @@ -230,7 +231,7 @@ tests += loadtest restest1 preloadtest l tst-audit1 tst-audit2 \ tst-stackguard1 tst-addr1 tst-thrlock \ tst-unique1 tst-unique2 tst-unique3 tst-unique4 \ - tst-initorder tst-initorder2 + tst-initorder tst-initorder2 tst-relsort1 # reldep9 test-srcs = tst-pathopt selinux-enabled := $(shell cat /selinux/enforce 2> /dev/null) @@ -293,7 +294,9 @@ modules-names = testobj1 testobj2 testob tst-initordera1 tst-initorderb1 \ tst-initordera2 tst-initorderb2 \ tst-initordera3 tst-initordera4 \ - tst-initorder2a tst-initorder2b tst-initorder2c tst-initorder2d + tst-initorder2a tst-initorder2b tst-initorder2c \ + tst-initorder2d \ + tst-relsort1mod1 tst-relsort1mod2 ifeq (yes,$(have-initfini-array)) modules-names += tst-array2dep tst-array5dep endif @@ -1198,3 +1201,9 @@ CFLAGS-tst-auditmod6b.c += $(AVX-CFLAGS) CFLAGS-tst-auditmod6c.c += $(AVX-CFLAGS) CFLAGS-tst-auditmod7b.c += $(AVX-CFLAGS) endif + +$(objpfx)tst-relsort1: $(libdl) +$(objpfx)tst-relsort1mod1.so: $(libm) $(objpfx)tst-relsort1mod2.so +$(objpfx)tst-relsort1mod2.so: $(libm) +$(objpfx)tst-relsort1.out: $(objpfx)tst-relsort1mod1.so \ + $(objpfx)tst-relsort1mod2.so Index: glibc-2.15/elf/dl-open.c =================================================================== --- glibc-2.15.orig/elf/dl-open.c +++ glibc-2.15/elf/dl-open.c @@ -1,5 +1,5 @@ /* Load a shared object at runtime, relocate it, and run its initializer. - Copyright (C) 1996-2007, 2009, 2010, 2011 Free Software Foundation, Inc. + Copyright (C) 1996-2007, 2009, 2010, 2011, 2012 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 @@ -302,45 +302,109 @@ dl_open_worker (void *a) if (GLRO(dl_lazy)) reloc_mode |= mode & RTLD_LAZY; - /* Relocate the objects loaded. We do this in reverse order so that copy - relocs of earlier objects overwrite the data written by later objects. */ - + /* Sort the objects by dependency for the relocation process. This + allows IFUNC relocations to work and it also means copy + relocation of dependencies are if necessary overwritten. */ + size_t nmaps = 0; struct link_map *l = new; - while (l->l_next) - l = l->l_next; - while (1) + do + { + if (! l->l_real->l_relocated) + ++nmaps; + l = l->l_next; + } + while (l != NULL); + struct link_map *maps[nmaps]; + nmaps = 0; + l = new; + do { if (! l->l_real->l_relocated) + maps[nmaps++] = l; + l = l->l_next; + } + while (l != NULL); + if (nmaps > 1) + { + char seen[nmaps]; + memset (seen, '\0', nmaps); + size_t i = 0; + while (1) { -#ifdef SHARED - if (__builtin_expect (GLRO(dl_profile) != NULL, 0)) + ++seen[i]; + struct link_map *thisp = maps[i]; + + /* Find the last object in the list for which the current one is + a dependency and move the current object behind the object + with the dependency. */ + size_t k = nmaps - 1; + while (k > i) { - /* If this here is the shared object which we want to profile - make sure the profile is started. We can find out whether - this is necessary or not by observing the `_dl_profile_map' - variable. If was NULL but is not NULL afterwars we must - start the profiling. */ - struct link_map *old_profile_map = GL(dl_profile_map); - - _dl_relocate_object (l, l->l_scope, reloc_mode | RTLD_LAZY, 1); - - if (old_profile_map == NULL && GL(dl_profile_map) != NULL) - { - /* We must prepare the profiling. */ - _dl_start_profile (); - - /* Prevent unloading the object. */ - GL(dl_profile_map)->l_flags_1 |= DF_1_NODELETE; - } + struct link_map **runp = maps[k]->l_initfini; + if (runp != NULL) + /* Look through the dependencies of the object. */ + while (*runp != NULL) + if (__builtin_expect (*runp++ == thisp, 0)) + { + /* Move the current object to the back past the last + object with it as the dependency. */ + memmove (&maps[i], &maps[i + 1], + (k - i) * sizeof (maps[0])); + maps[k] = thisp; + + if (seen[i + 1] > 1) + { + ++i; + goto next_clear; + } + + char this_seen = seen[i]; + memmove (&seen[i], &seen[i + 1], + (k - i) * sizeof (seen[0])); + seen[k] = this_seen; + + goto next; + } + + --k; } - else -#endif - _dl_relocate_object (l, l->l_scope, reloc_mode, 0); + + if (++i == nmaps) + break; + next_clear: + memset (&seen[i], 0, (nmaps - i) * sizeof (seen[0])); + next:; } + } + + for (size_t i = nmaps; i-- > 0; ) + { + l = maps[i]; + +#ifdef SHARED + if (__builtin_expect (GLRO(dl_profile) != NULL, 0)) + { + /* If this here is the shared object which we want to profile + make sure the profile is started. We can find out whether + this is necessary or not by observing the `_dl_profile_map' + variable. If it was NULL but is not NULL afterwars we must + start the profiling. */ + struct link_map *old_profile_map = GL(dl_profile_map); - if (l == new) - break; - l = l->l_prev; + _dl_relocate_object (l, l->l_scope, reloc_mode | RTLD_LAZY, 1); + + if (old_profile_map == NULL && GL(dl_profile_map) != NULL) + { + /* We must prepare the profiling. */ + _dl_start_profile (); + + /* Prevent unloading the object. */ + GL(dl_profile_map)->l_flags_1 |= DF_1_NODELETE; + } + } + else +#endif + _dl_relocate_object (l, l->l_scope, reloc_mode, 0); } /* If the file is not loaded now as a dependency, add the search Index: glibc-2.15/elf/tst-relsort1.c =================================================================== --- /dev/null +++ glibc-2.15/elf/tst-relsort1.c @@ -0,0 +1,19 @@ +#include +#include + + +static int +do_test () +{ + const char lib[] = "$ORIGIN/tst-relsort1mod1.so"; + void *h = dlopen (lib, RTLD_NOW); + if (h == NULL) + { + puts (dlerror ()); + return 1; + } + return 0; +} + +#define TEST_FUNCTION do_test () +#include "../test-skeleton.c" Index: glibc-2.15/elf/tst-relsort1mod1.c =================================================================== --- /dev/null +++ glibc-2.15/elf/tst-relsort1mod1.c @@ -0,0 +1,7 @@ +extern int foo (double); + +int +bar (void) +{ + return foo (1.2); +} Index: glibc-2.15/elf/tst-relsort1mod2.c =================================================================== --- /dev/null +++ glibc-2.15/elf/tst-relsort1mod2.c @@ -0,0 +1,7 @@ +#include + +int +foo (double d) +{ + return floor (d) != 0.0; +}