glibc/elf/tst-nodelete-rtldmod.cc

extern int not_exist (void);

int foo (void)
{
  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 15:45:46 +00:00			`extern int not_exist (void);`

			`int foo (void)`
			`{`
			`return not_exist ();`
			`}`