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simplify dynamic linker startup 

instead of creating temp dso objects on the stack and moving them to
the heap if dlopen/dlsym are used, use static objects to begin with,
and just donate them to malloc if we no longer need them.
This commit is contained in:
Rich Felker 2011-07-24 00:26:12 -04:00
parent e3eb49321c
commit a53de812d2
1 changed files with 17 additions and 23 deletions
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40
src/ldso/dynlink.c
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@ -443,7 +443,9 @@ void *__dynlink(int argc, char **argv, size_t *got)
size_t i;
Phdr *phdr;
Ehdr *ehdr;
struct dso lib, app;
static struct dso builtin_dsos[2];
struct dso *const app = builtin_dsos+0;
struct dso *const lib = builtin_dsos+1;
/* Find aux vector just past environ[] */
for (i=argc+1; argv[i]; i++)
@ -471,7 +473,7 @@ void *__dynlink(int argc, char **argv, size_t *got)
}
}
app = (struct dso){
*app = (struct dso){
.base = 0,
.strings = (void *)(app_dyn[DT_STRTAB]),
.hashtab = (void *)(app_dyn[DT_HASH]),
@ -479,10 +481,10 @@ void *__dynlink(int argc, char **argv, size_t *got)
.dynv = (void *)(phdr->p_vaddr),
.name = argv[0],
.global = 1,
.next = &lib
.next = lib
};
lib = (struct dso){
*lib = (struct dso){
.base = (void *)aux[AT_BASE],
.strings = (void *)(aux[AT_BASE]+lib_dyn[DT_STRTAB]),
.hashtab = (void *)(aux[AT_BASE]+lib_dyn[DT_HASH]),
@ -495,39 +497,31 @@ void *__dynlink(int argc, char **argv, size_t *got)
/* Relocate the dynamic linker/libc */
do_relocs((void *)aux[AT_BASE], (void *)(aux[AT_BASE]+lib_dyn[DT_REL]),
lib_dyn[DT_RELSZ], 2, lib.syms, lib.strings, &app);
lib_dyn[DT_RELSZ], 2, lib->syms, lib->strings, app);
do_relocs((void *)aux[AT_BASE], (void *)(aux[AT_BASE]+lib_dyn[DT_RELA]),
lib_dyn[DT_RELASZ], 3, lib.syms, lib.strings, &app);
lib_dyn[DT_RELASZ], 3, lib->syms, lib->strings, app);
/* At this point the standard library is fully functional */
reclaim_gaps(app.base, (void *)aux[AT_PHDR], aux[AT_PHENT], aux[AT_PHNUM]);
ehdr = (void *)lib.base;
reclaim_gaps(lib.base, (void *)(lib.base+ehdr->e_phoff),
reclaim_gaps(app->base, (void *)aux[AT_PHDR], aux[AT_PHENT], aux[AT_PHNUM]);
ehdr = (void *)lib->base;
reclaim_gaps(lib->base, (void *)(lib->base+ehdr->e_phoff),
ehdr->e_phentsize, ehdr->e_phnum);
head = tail = &app;
libc = &lib;
app.next = 0;
head = tail = app;
libc = lib;
app->next = 0;
load_deps(head);
make_global(head);
reloc_all(head->next);
reloc_all(head);
if (rtld_used) {
runtime = 1;
head->next->prev = malloc(sizeof *head);
*head->next->prev = *head;
head = head->next->prev;
libc->prev->next = malloc(sizeof *libc);
*libc->prev->next = *libc;
libc = libc->prev->next;
if (libc->next) libc->next->prev = libc;
if (tail == &lib) tail = libc;
} else {
runtime = 1;
if (!rtld_used) {
free_all(head);
free(sys_path);
reclaim((void *)builtin_dsos, 0, sizeof builtin_dsos);
}
errno = 0;