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authorkan <kan@FreeBSD.org>2003-05-08 01:31:36 +0000
committerkan <kan@FreeBSD.org>2003-05-08 01:31:36 +0000
commitc47ebbd98f7167ae78a7885c1afa61c6439b5f90 (patch)
tree45d48a8463c8db69b73ca13955997b0d172f2c95 /libexec
parent2d5f55a20d28a25fb5707f3162e2a66f2b58e0a2 (diff)
downloadFreeBSD-src-c47ebbd98f7167ae78a7885c1afa61c6439b5f90.zip
FreeBSD-src-c47ebbd98f7167ae78a7885c1afa61c6439b5f90.tar.gz
Rethink the way we count module references. Simply following
DT_NEEDED links is not flexible enough for cases where dynamically loaded modules form a dependency cycle. This should fix an infinite recursion problem encountered by Yahoo. Approved by: re (jhb)
Diffstat (limited to 'libexec')
-rw-r--r--libexec/rtld-elf/rtld.c48
1 files changed, 30 insertions, 18 deletions
diff --git a/libexec/rtld-elf/rtld.c b/libexec/rtld-elf/rtld.c
index 06a78a6..adb156a 100644
--- a/libexec/rtld-elf/rtld.c
+++ b/libexec/rtld-elf/rtld.c
@@ -126,6 +126,7 @@ static void trace_loaded_objects(Obj_Entry *obj);
static void unlink_object(Obj_Entry *);
static void unload_object(Obj_Entry *);
static void unref_dag(Obj_Entry *);
+static void ref_dag(Obj_Entry *);
void r_debug_state(struct r_debug*, struct link_map*);
@@ -361,7 +362,6 @@ _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
*obj_tail = obj_main;
obj_tail = &obj_main->next;
obj_count++;
- obj_main->refcount++;
/* Make sure we don't call the main program's init and fini functions. */
obj_main->init = obj_main->fini = NULL;
@@ -383,8 +383,10 @@ _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
die();
/* Make a list of all objects loaded at startup. */
- for (obj = obj_list; obj != NULL; obj = obj->next)
+ for (obj = obj_list; obj != NULL; obj = obj->next) {
objlist_push_tail(&list_main, obj);
+ obj->refcount++;
+ }
if (ld_tracing) { /* We're done */
trace_loaded_objects(obj_main);
@@ -970,6 +972,8 @@ init_dag1(Obj_Entry *root, Obj_Entry *obj, DoneList *dlp)
if (donelist_check(dlp, obj))
return;
+
+ obj->refcount++;
objlist_push_tail(&obj->dldags, root);
objlist_push_tail(&root->dagmembers, obj);
for (needed = obj->needed; needed != NULL; needed = needed->next)
@@ -1223,7 +1227,6 @@ load_object(char *path)
} else
free(path);
- obj->refcount++;
return obj;
}
@@ -1579,6 +1582,7 @@ dlclose(void *handle)
/* Unreference the object and its dependencies. */
root->dl_refcount--;
+
unref_dag(root);
if (root->refcount == 0) {
@@ -1682,8 +1686,14 @@ dlopen(const char *name, int mode)
/* Make list of init functions to call. */
initlist_add_objects(obj, &obj->next, &initlist);
}
- } else if (ld_tracing)
- goto trace;
+ } else {
+
+ /* Bump the reference counts for objects on this DAG. */
+ ref_dag(obj);
+
+ if (ld_tracing)
+ goto trace;
+ }
}
GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
@@ -2405,7 +2415,6 @@ unload_object(Obj_Entry *root)
static void
unlink_object(Obj_Entry *root)
{
- const Needed_Entry *needed;
Objlist_Entry *elm;
if (root->refcount == 0) {
@@ -2413,25 +2422,28 @@ unlink_object(Obj_Entry *root)
objlist_remove(&list_global, root);
/* Remove the object from all objects' DAG lists. */
- STAILQ_FOREACH(elm, &root->dagmembers , link)
+ STAILQ_FOREACH(elm, &root->dagmembers , link) {
objlist_remove(&elm->obj->dldags, root);
+ if (elm->obj != root)
+ unlink_object(elm->obj);
+ }
}
+}
- for (needed = root->needed; needed != NULL; needed = needed->next)
- if (needed->obj != NULL)
- unlink_object(needed->obj);
+static void
+ref_dag(Obj_Entry *root)
+{
+ Objlist_Entry *elm;
+
+ STAILQ_FOREACH(elm, &root->dagmembers , link)
+ elm->obj->refcount++;
}
static void
unref_dag(Obj_Entry *root)
{
- const Needed_Entry *needed;
+ Objlist_Entry *elm;
- if (root->refcount == 0)
- return;
- root->refcount--;
- if (root->refcount == 0)
- for (needed = root->needed; needed != NULL; needed = needed->next)
- if (needed->obj != NULL)
- unref_dag(needed->obj);
+ STAILQ_FOREACH(elm, &root->dagmembers , link)
+ elm->obj->refcount--;
}
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