glibc/elf/tst-nodelete2mod.c

/* Undefined symbol.  */
extern int not_exist (void);

int foo (void)
{
  return not_exist ();
}
Clear DF_1_NODELETE flag only for failed to load library. https://sourceware.org/bugzilla/show_bug.cgi?id=18778 If dlopen fails to load an object that has triggered loading libpthread it causes ld.so to unload libpthread because its DF_1_NODELETE flags has been forcefully cleared. The next call to __rtdl_unlock_lock_recursive will crash since pthread_mutex_unlock no longer exists. This patch moves l->l_flags_1 &= ~DF_1_NODELETE out of loop through all loaded libraries and performs the action only on inconsistent one. [BZ #18778] * elf/Makefile (tests): Add Add tst-nodelete2. (modules-names): Add tst-nodelete2mod. (tst-nodelete2mod.so-no-z-defs): New. ($(objpfx)tst-nodelete2): Likewise. ($(objpfx)tst-nodelete2.out): Likewise. (LDFLAGS-tst-nodelete2): Likewise. * elf/dl-close.c (_dl_close_worker): Move DF_1_NODELETE clearing out of loop through all loaded libraries. * elf/tst-nodelete2.c: New file. * elf/tst-nodelete2mod.c: Likewise. 2015-08-10 15:47:54 +08:00			`/* Undefined symbol. */`
Add forced deletion support to _dl_close_worker https://sourceware.org/bugzilla/show_bug.cgi?id=17833 I've a shared library that contains both undefined and unique symbols. Then I try to call the following sequence of dlopen: 1. dlopen("./libfoo.so", RTLD_NOW) 2. dlopen("./libfoo.so", RTLD_LAZY \| RTLD_GLOBAL) First dlopen call terminates with error because of undefined symbols, but STB_GNU_UNIQUE ones set DF_1_NODELETE flag and hence block library in the memory. The library goes into inconsistent state as several structures remain uninitialized. For instance, relocations for GOT table were not performed. By the time of second dlopen call this library looks like as it would be fully initialized but this is not true: any call through incorrect GOT table leads to segmentation fault. On some systems this inconsistency triggers assertions in the dynamic linker. This patch adds a parameter to _dl_close_worker to implement forced object deletion in case of dlopen() failure: 1. Clears DF_1_NODELETE bit if forced, to allow library to be removed from memory. 2. For each unique symbol that is defined in this object clears appropriate entry in _ns_unique_sym_table. [BZ #17833] * elf/Makefile (tests): Add tst-nodelete. (modules-names): Add tst-nodelete-uniquemod. (tst-nodelete-uniquemod.so-no-z-defs): New. (tst-nodelete-rtldmod.so-no-z-defs): Likewise. (tst-nodelete-zmod.so-no-z-defs): Likewise. ($(objpfx)tst-nodelete): Likewise. ($(objpfx)tst-nodelete.out): Likewise. (LDFLAGS-tst-nodelete): Likewise. (LDFLAGS-tst-nodelete-zmod.so): Likewise. * elf/dl-close.c (_dl_close_worker): Add a parameter to implement forced object deletion. (_dl_close): Pass false to _dl_close_worker. * elf/dl-open.c (_dl_open): Pass true to _dl_close_worker. * elf/tst-nodelete.cc: New file. * elf/tst-nodeletelib.cc: Likewise. * elf/tst-znodeletelib.cc: Likewise. * include/dlfcn.h (_dl_close_worker): Add a new parameter. 2015-07-07 23:45:46 +08:00			`extern int not_exist (void);`

			`int foo (void)`
			`{`
Clear DF_1_NODELETE flag only for failed to load library. https://sourceware.org/bugzilla/show_bug.cgi?id=18778 If dlopen fails to load an object that has triggered loading libpthread it causes ld.so to unload libpthread because its DF_1_NODELETE flags has been forcefully cleared. The next call to __rtdl_unlock_lock_recursive will crash since pthread_mutex_unlock no longer exists. This patch moves l->l_flags_1 &= ~DF_1_NODELETE out of loop through all loaded libraries and performs the action only on inconsistent one. [BZ #18778] * elf/Makefile (tests): Add Add tst-nodelete2. (modules-names): Add tst-nodelete2mod. (tst-nodelete2mod.so-no-z-defs): New. ($(objpfx)tst-nodelete2): Likewise. ($(objpfx)tst-nodelete2.out): Likewise. (LDFLAGS-tst-nodelete2): Likewise. * elf/dl-close.c (_dl_close_worker): Move DF_1_NODELETE clearing out of loop through all loaded libraries. * elf/tst-nodelete2.c: New file. * elf/tst-nodelete2mod.c: Likewise. 2015-08-10 15:47:54 +08:00			`return not_exist ();`
Add forced deletion support to _dl_close_worker https://sourceware.org/bugzilla/show_bug.cgi?id=17833 I've a shared library that contains both undefined and unique symbols. Then I try to call the following sequence of dlopen: 1. dlopen("./libfoo.so", RTLD_NOW) 2. dlopen("./libfoo.so", RTLD_LAZY \| RTLD_GLOBAL) First dlopen call terminates with error because of undefined symbols, but STB_GNU_UNIQUE ones set DF_1_NODELETE flag and hence block library in the memory. The library goes into inconsistent state as several structures remain uninitialized. For instance, relocations for GOT table were not performed. By the time of second dlopen call this library looks like as it would be fully initialized but this is not true: any call through incorrect GOT table leads to segmentation fault. On some systems this inconsistency triggers assertions in the dynamic linker. This patch adds a parameter to _dl_close_worker to implement forced object deletion in case of dlopen() failure: 1. Clears DF_1_NODELETE bit if forced, to allow library to be removed from memory. 2. For each unique symbol that is defined in this object clears appropriate entry in _ns_unique_sym_table. [BZ #17833] * elf/Makefile (tests): Add tst-nodelete. (modules-names): Add tst-nodelete-uniquemod. (tst-nodelete-uniquemod.so-no-z-defs): New. (tst-nodelete-rtldmod.so-no-z-defs): Likewise. (tst-nodelete-zmod.so-no-z-defs): Likewise. ($(objpfx)tst-nodelete): Likewise. ($(objpfx)tst-nodelete.out): Likewise. (LDFLAGS-tst-nodelete): Likewise. (LDFLAGS-tst-nodelete-zmod.so): Likewise. * elf/dl-close.c (_dl_close_worker): Add a parameter to implement forced object deletion. (_dl_close): Pass false to _dl_close_worker. * elf/dl-open.c (_dl_open): Pass true to _dl_close_worker. * elf/tst-nodelete.cc: New file. * elf/tst-nodeletelib.cc: Likewise. * elf/tst-znodeletelib.cc: Likewise. * include/dlfcn.h (_dl_close_worker): Add a new parameter. 2015-07-07 23:45:46 +08:00			`}`