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Diffstat (limited to 'ldso')
-rw-r--r--ldso/dynlink.c118
1 files changed, 101 insertions, 17 deletions
diff --git a/ldso/dynlink.c b/ldso/dynlink.c
index 2617d553..777be489 100644
--- a/ldso/dynlink.c
+++ b/ldso/dynlink.c
@@ -76,6 +76,8 @@ struct dso {
char runtime_loaded;
struct dso **deps, *needed_by;
size_t ndeps_direct;
+ size_t next_dep;
+ int ctor_visitor;
char *rpath_orig, *rpath;
struct tls_module tls;
size_t tls_id;
@@ -128,7 +130,9 @@ static struct debug debug;
static struct tls_module *tls_tail;
static size_t tls_cnt, tls_offset, tls_align = MIN_TLS_ALIGN;
static size_t static_tls_cnt;
-static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
+static pthread_mutex_t init_fini_lock;
+static pthread_cond_t ctor_cond;
+static struct dso **main_ctor_queue;
static struct fdpic_loadmap *app_loadmap;
static struct fdpic_dummy_loadmap app_dummy_loadmap;
@@ -1361,22 +1365,87 @@ void __libc_exit_fini()
}
}
-static void do_init_fini(struct dso *p)
+static struct dso **queue_ctors(struct dso *dso)
{
- size_t dyn[DYN_CNT];
- int need_locking = libc.threads_minus_1;
- /* Allow recursive calls that arise when a library calls
- * dlopen from one of its constructors, but block any
- * other threads until all ctors have finished. */
- if (need_locking) pthread_mutex_lock(&init_fini_lock);
- for (; p; p=p->prev) {
+ size_t cnt, qpos, spos, i;
+ struct dso *p, **queue, **stack;
+
+ if (ldd_mode) return 0;
+
+ /* Bound on queue size is the total number of indirect deps.
+ * If a bfs deps list was built, we can use it. Otherwise,
+ * bound by the total number of DSOs, which is always safe and
+ * is reasonable we use it (for main app at startup). */
+ if (dso->bfs_built) {
+ for (cnt=0; dso->deps[cnt]; cnt++)
+ dso->deps[cnt]->mark = 0;
+ cnt++; /* self, not included in deps */
+ } else {
+ for (cnt=0, p=head; p; cnt++, p=p->next)
+ p->mark = 0;
+ }
+ cnt++; /* termination slot */
+ stack = queue = calloc(cnt, sizeof *queue);
+
+ if (!queue) {
+ error("Error allocating constructor queue: %m\n");
+ if (runtime) longjmp(*rtld_fail, 1);
+ return 0;
+ }
+
+ /* Opposite ends of the allocated buffer serve as an output queue
+ * and a working stack. Setup initial stack with just the argument
+ * dso and initial queue empty... */
+ qpos = 0;
+ spos = cnt;
+ stack[--spos] = dso;
+ dso->next_dep = 0;
+ dso->mark = 1;
+
+ /* Then perform pseudo-DFS sort, but ignoring circular deps. */
+ while (spos<cnt) {
+ p = stack[spos++];
+ while (p->next_dep < p->ndeps_direct) {
+ if (p->deps[p->next_dep]->mark) {
+ p->next_dep++;
+ } else {
+ stack[--spos] = p;
+ p = p->deps[p->next_dep];
+ p->next_dep = 0;
+ p->mark = 1;
+ }
+ }
+ queue[qpos++] = p;
+ }
+ queue[qpos] = 0;
+ for (i=0; i<qpos; i++) queue[i]->mark = 0;
+
+ return queue;
+}
+
+static void do_init_fini(struct dso **queue)
+{
+ struct dso *p;
+ size_t dyn[DYN_CNT], i;
+ int self = __pthread_self()->tid;
+
+ pthread_mutex_lock(&init_fini_lock);
+ for (i=0; (p=queue[i]); i++) {
+ while (p->ctor_visitor && p->ctor_visitor!=self)
+ pthread_cond_wait(&ctor_cond, &init_fini_lock);
+ if (p->ctor_visitor || p->constructed)
+ continue;
if (p->constructed) continue;
- p->constructed = 1;
+ p->ctor_visitor = self;
+
decode_vec(p->dynv, dyn, DYN_CNT);
if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
p->fini_next = fini_head;
fini_head = p;
}
+
+ pthread_mutex_unlock(&init_fini_lock);
+
#ifndef NO_LEGACY_INITFINI
if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
fpaddr(p, dyn[DT_INIT])();
@@ -1386,17 +1455,22 @@ static void do_init_fini(struct dso *p)
size_t *fn = laddr(p, dyn[DT_INIT_ARRAY]);
while (n--) ((void (*)(void))*fn++)();
}
- if (!need_locking && libc.threads_minus_1) {
- need_locking = 1;
- pthread_mutex_lock(&init_fini_lock);
- }
+
+ pthread_mutex_lock(&init_fini_lock);
+ p->ctor_visitor = 0;
+ p->constructed = 1;
+ pthread_cond_broadcast(&ctor_cond);
}
- if (need_locking) pthread_mutex_unlock(&init_fini_lock);
+ pthread_mutex_unlock(&init_fini_lock);
}
void __libc_start_init(void)
{
- do_init_fini(tail);
+ do_init_fini(main_ctor_queue);
+ /* This is valid because the queue was allocated after redoing
+ * relocations with any interposed malloc having taken effect. */
+ free(main_ctor_queue);
+ main_ctor_queue = 0;
}
static void dl_debug_state(void)
@@ -1793,6 +1867,8 @@ _Noreturn void __dls3(size_t *sp)
}
static_tls_cnt = tls_cnt;
+ main_ctor_queue = queue_ctors(&app);
+
if (ldso_fail) _exit(127);
if (ldd_mode) _exit(0);
@@ -1852,6 +1928,7 @@ void *dlopen(const char *file, int mode)
size_t i;
int cs;
jmp_buf jb;
+ struct dso **volatile ctor_queue = 0;
if (!file) return head;
@@ -1886,6 +1963,7 @@ void *dlopen(const char *file, int mode)
free(p->deps);
unmap_library(p);
free(p);
+ free(ctor_queue);
}
if (!orig_tls_tail) libc.tls_head = 0;
tls_tail = orig_tls_tail;
@@ -1911,6 +1989,9 @@ void *dlopen(const char *file, int mode)
/* First load handling */
load_deps(p);
extend_bfs_deps(p);
+ pthread_mutex_lock(&init_fini_lock);
+ if (!p->constructed) ctor_queue = queue_ctors(p);
+ pthread_mutex_unlock(&init_fini_lock);
if (!p->relocated && (mode & RTLD_LAZY)) {
prepare_lazy(p);
for (i=0; p->deps[i]; i++)
@@ -1948,7 +2029,10 @@ end:
__release_ptc();
if (p) gencnt++;
pthread_rwlock_unlock(&lock);
- if (p) do_init_fini(orig_tail);
+ if (ctor_queue) {
+ do_init_fini(ctor_queue);
+ free(ctor_queue);
+ }
pthread_setcancelstate(cs, 0);
return p;
}