svn commit: r215084 - stable/8/libexec/rtld-elf

[Konstantin Belousov]

Author: kib
Date: Wed Nov 10 08:46:29 2010
New Revision: 215084
URL: http://svn.freebsd.org/changeset/base/215084

Log:
  MFC r214728:
  If dlopen() is called for the dso that has been already loaded as a
  dependency, then the dso never has its DAG initialized. Empty DAG
  makes ref_dag() call in dlopen() a nop, and the dso refcount is off
  by one.
  
  Initialize the DAG on the first dlopen() call, using a boolean flag
  to prevent double initialization.
  
  MFC r214776:
  Fix style.
  
  MFC r214777:
  Change init_dag() to not increment DAG refcount. Unconditionally call
  both init_dag() and ref_dag() in dlopen() for the case when the object
  was already loaded.

Modified:
  stable/8/libexec/rtld-elf/rtld.c
  stable/8/libexec/rtld-elf/rtld.h
Directory Properties:
  stable/8/libexec/rtld-elf/   (props changed)

Modified: stable/8/libexec/rtld-elf/rtld.c
==============================================================================
--- stable/8/libexec/rtld-elf/rtld.c	Wed Nov 10 08:21:25 2010	(r215083)
+++ stable/8/libexec/rtld-elf/rtld.c	Wed Nov 10 08:46:29 2010	(r215084)
@@ -1278,8 +1278,11 @@ init_dag(Obj_Entry *root)
 {
     DoneList donelist;
 
+    if (root->dag_inited)
+	return;
     donelist_init(&donelist);
     init_dag1(root, root, &donelist);
+    root->dag_inited = true;
 }
 
 static void
@@ -1290,7 +1293,6 @@ init_dag1(Obj_Entry *root, Obj_Entry *ob
     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)
@@ -2035,6 +2037,7 @@ dlopen(const char *name, int mode)
 	    assert(*old_obj_tail == obj);
 	    result = load_needed_objects(obj, RTLD_LO_DLOPEN);
 	    init_dag(obj);
+	    ref_dag(obj);
 	    if (result != -1)
 		result = rtld_verify_versions(&obj->dagmembers);
 	    if (result != -1 && ld_tracing)
@@ -2052,7 +2055,13 @@ dlopen(const char *name, int mode)
 	    }
 	} else {
 
-	    /* Bump the reference counts for objects on this DAG. */
+	    /*
+	     * Bump the reference counts for objects on this DAG.  If
+	     * this is the first dlopen() call for the object that was
+	     * already loaded as a dependency, initialize the dag
+	     * starting at it.
+	     */
+	    init_dag(obj);
 	    ref_dag(obj);
 
 	    if (ld_tracing)
@@ -3059,6 +3068,7 @@ ref_dag(Obj_Entry *root)
 {
     Objlist_Entry *elm;
 
+    assert(root->dag_inited);
     STAILQ_FOREACH(elm, &root->dagmembers, link)
 	elm->obj->refcount++;
 }
@@ -3068,6 +3078,7 @@ unref_dag(Obj_Entry *root)
 {
     Objlist_Entry *elm;
 
+    assert(root->dag_inited);
     STAILQ_FOREACH(elm, &root->dagmembers, link)
 	elm->obj->refcount--;
 }

Modified: stable/8/libexec/rtld-elf/rtld.h
==============================================================================
--- stable/8/libexec/rtld-elf/rtld.h	Wed Nov 10 08:21:25 2010	(r215083)
+++ stable/8/libexec/rtld-elf/rtld.h	Wed Nov 10 08:46:29 2010	(r215084)
@@ -222,6 +222,7 @@ typedef struct Struct_Obj_Entry {
     bool ref_nodel : 1;		/* Refcount increased to prevent dlclose */
     bool init_scanned: 1;	/* Object is already on init list. */
     bool on_fini_list: 1;	/* Object is already on fini list. */
+    bool dag_inited : 1;	/* Object has its DAG initialized. */
 
     struct link_map linkmap;	/* For GDB and dlinfo() */
     Objlist dldags;		/* Object belongs to these dlopened DAGs (%) */