fix dlsym RTLD_NEXT behavior for fdpic
lookup the dso an address falls in based on the loadmap and not just a
base/length. fix the main app's fake loadmap used when loaded by a
non-fdpic-aware loader so that it does not cover the whole memory
space.
function descriptor addresses are also matched for future use by
dladdr, but reverse lookups of function descriptors via dladdr have
not been implemented yet. some revisions may be needed in the future
once reclaim_gaps supports fdpic, so that function descriptors
allocated in reclaimed heap space do not get detected as belonging to
the module whose gaps they were allocated in.
diff --git a/src/ldso/dynlink.c b/src/ldso/dynlink.c
index 0c3b36c..cab3008 100644
--- a/src/ldso/dynlink.c
+++ b/src/ldso/dynlink.c
@@ -1543,8 +1543,10 @@
if (!app.loadmap) {
app.loadmap = (void *)&app_dummy_loadmap;
app.loadmap->nsegs = 1;
- app.loadmap->segs[0].addr = (size_t)app.base;
- app.loadmap->segs[0].p_memsz = -1;
+ app.loadmap->segs[0].addr = (size_t)app.map;
+ app.loadmap->segs[0].p_vaddr = (size_t)app.map
+ - (size_t)app.base;
+ app.loadmap->segs[0].p_memsz = app.map_len;
}
argv[-3] = (void *)app.loadmap;
}
@@ -1738,6 +1740,28 @@
return 1;
}
+static void *addr2dso(size_t a)
+{
+ struct dso *p;
+ for (p=head; p; p=p->next) {
+ if (DL_FDPIC && p->loadmap) {
+ size_t i;
+ for (i=0; i<p->loadmap->nsegs; i++) {
+ if (a-p->loadmap->segs[i].p_vaddr
+ < p->loadmap->segs[i].p_memsz)
+ return p;
+ }
+ i = count_syms(p);
+ if (a-(size_t)p->funcdescs < i*sizeof(*p->funcdescs))
+ return p;
+ } else {
+ if (a-(size_t)p->map < p->map_len)
+ return p;
+ }
+ }
+ return 0;
+}
+
void *__tls_get_addr(size_t *);
static void *do_dlsym(struct dso *p, const char *s, void *ra)
@@ -1749,7 +1773,7 @@
if (p == RTLD_DEFAULT) {
p = head;
} else if (p == RTLD_NEXT) {
- for (p=head; p && (unsigned char *)ra-p->map>p->map_len; p=p->next);
+ p = addr2dso((size_t)ra);
if (!p) p=head;
p = p->next;
}
@@ -1806,7 +1830,7 @@
char *bestname;
pthread_rwlock_rdlock(&lock);
- for (p=head; p && (unsigned char *)addr-p->map>p->map_len; p=p->next);
+ p = addr2dso((size_t)addr);
pthread_rwlock_unlock(&lock);
if (!p) return 0;