dynamic linker support for PIE binaries (position-independent main program)

even with this change, PIE will not work yet due to deficiencies in
the crt1.o startup code.
This commit is contained in:
Rich Felker 2012-01-23 02:02:59 -05:00
parent c82f4a32ec
commit e12fe65c92
1 changed files with 6 additions and 3 deletions

View File

@ -511,10 +511,13 @@ void *__dynlink(int argc, char **argv)
ehdr->e_phnum, ehdr->e_phentsize)); ehdr->e_phnum, ehdr->e_phentsize));
decode_dyn(lib); decode_dyn(lib);
/* Assume base address of 0 for the main program. This is not /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
* valid for PIE code; we will have to search the PHDR to get
* the correct load address in the PIE case (not yet supported). */
app->base = 0; app->base = 0;
phdr = (void *)aux[AT_PHDR];
for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
if (phdr->p_type == PT_PHDR)
app->base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
}
app->name = argv[0]; app->name = argv[0];
app->global = 1; app->global = 1;
app->dynv = (void *)(app->base + find_dyn( app->dynv = (void *)(app->base + find_dyn(