2005-04-26 Jakub Jelinek <jakub@redhat.com>

[BZ #1081]
	* elf/dl-close.c: Include stddef.h.
	(_dl_close): If called recursively, just remember GC needs to be rerun
	and decrease l_direct_opencount.  Avoid GC if l_direct_opencount
	decreased to 1.  Rerun GC at the end if any destructor unloaded some
	additional libraries.
	* elf/Makefile: Add rules to build and run unload6 test.
	* elf/unload6.c: New test.
	* elf/unload6mod1.c: New file.
	* elf/unload6mod2.c: New file.
	* elf/unload6mod3.c: New file.

elf/Makefile

@@ -86,6 +86,7 @@ distribute	:= rtld-Rules \
 		   tst-deep1mod1.c tst-deep1mod2.c tst-deep1mod3.c \
 		   unload3mod1.c unload3mod2.c unload3mod3.c unload3mod4.c \
 		   unload4mod1.c unload4mod2.c unload4mod3.c unload4mod4.c \
+		   unload6mod1.c unload6mod2.c unload6mod3.c \
 		   order2mod1.c order2mod2.c order2mod3.c order2mod4.c
 
 CFLAGS-dl-runtime.c = -fexceptions -fasynchronous-unwind-tables
@@ -158,7 +159,7 @@ tests += loadtest restest1 preloadtest loadfail multiload origtest resolvfail \
 	 tst-tls10 tst-tls11 tst-tls12 tst-tls13 tst-tls14 tst-align \
 	 tst-align2 $(tests-execstack-$(have-z-execstack)) tst-dlmodcount \
 	 tst-dlopenrpath tst-deep1 tst-dlmopen1 tst-dlmopen2 tst-dlmopen3 \
-	 unload3 unload4 unload5 tst-global1 order2
+	 unload3 unload4 unload5 unload6 tst-global1 order2
 #	 reldep9
 test-srcs = tst-pathopt
 tests-vis-yes = vismain
@@ -196,6 +197,7 @@ modules-names = testobj1 testobj2 testobj3 testobj4 testobj5 testobj6 \
 		tst-dlmopen1mod \
 		unload3mod1 unload3mod2 unload3mod3 unload3mod4 \
 		unload4mod1 unload4mod2 unload4mod3 unload4mod4 \
+		unload6mod1 unload6mod2 unload6mod3 \
 		order2mod1 order2mod2 order2mod3 order2mod4
 ifeq (yes,$(have-initfini-array))
 modules-names += tst-array2dep
@@ -433,6 +435,9 @@ $(objpfx)unload3mod2.so: $(objpfx)unload3mod3.so
 $(objpfx)unload3mod3.so: $(objpfx)unload3mod4.so
 $(objpfx)unload4mod1.so: $(objpfx)unload4mod2.so $(objpfx)unload4mod3.so
 $(objpfx)unload4mod2.so: $(objpfx)unload4mod4.so $(objpfx)unload4mod3.so
+$(objpfx)unload6mod1.so: $(libdl)
+$(objpfx)unload6mod2.so: $(libdl)
+$(objpfx)unload6mod3.so: $(libdl)
 
 LDFLAGS-tst-tlsmod5.so = -nostdlib
 LDFLAGS-tst-tlsmod6.so = -nostdlib
@@ -701,6 +706,10 @@ $(objpfx)unload5: $(libdl)
 $(objpfx)unload5.out: $(objpfx)unload3mod1.so $(objpfx)unload3mod2.so \
 		      $(objpfx)unload3mod3.so $(objpfx)unload3mod4.so
 
+$(objpfx)unload6: $(libdl)
+$(objpfx)unload6.out: $(objpfx)unload6mod1.so $(objpfx)unload6mod2.so \
+		      $(objpfx)unload6mod3.so
+
 ifdef libdl
 $(objpfx)tst-tls9-static: $(common-objpfx)dlfcn/libdl.a
 $(objpfx)tst-tls9-static.out: $(objpfx)tst-tlsmod5.so $(objpfx)tst-tlsmod6.so

elf/dl-close.c

@@ -20,6 +20,7 @@
 #include <assert.h>
 #include <dlfcn.h>
 #include <libintl.h>
+#include <stddef.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -105,9 +106,6 @@ _dl_close (void *_map)
   struct link_map *map = _map;
   unsigned int i;
   Lmid_t ns = map->l_ns;
-#ifdef USE_TLS
-  bool any_tls = false;
-#endif
 
   /* First see whether we can remove the object at all.  */
   if (__builtin_expect (map->l_flags_1 & DF_1_NODELETE, 0)
@@ -124,9 +122,17 @@ _dl_close (void *_map)
   /* One less direct use.  */
   --map->l_direct_opencount;
 
-  /* Decrement the reference count.  */
-  if (map->l_direct_opencount > 1 || map->l_type != lt_loaded)
+  /* If _dl_close is called recursively (some destructor call dlclose),
+     just record that the parent _dl_close will need to do garbage collection
+     again and return.  */
+  static enum { not_pending, pending, rerun } dl_close_state;
+
+  if (map->l_direct_opencount > 0 || map->l_type != lt_loaded
+      || dl_close_state != not_pending)
     {
+      if (map->l_direct_opencount == 0 && map->l_type == lt_loaded)
+	dl_close_state = rerun;
+
       /* There are still references to this object.  Do nothing more.  */
       if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_FILES, 0))
 	GLRO(dl_debug_printf) ("\nclosing file=%s; direct_opencount == %u\n",
@@ -136,12 +142,18 @@ _dl_close (void *_map)
       return;
     }
 
+ retry:
+  dl_close_state = pending;
+
+#ifdef USE_TLS
+  bool any_tls = false;
+#endif
   const unsigned int nloaded = GL(dl_ns)[ns]._ns_nloaded;
   char used[nloaded];
   char done[nloaded];
   struct link_map *maps[nloaded];
 
-  /* Run over the list and assign indeces to the link maps and enter
+  /* Run over the list and assign indexes to the link maps and enter
      them into the MAPS array.  */
   int idx = 0;
   for (struct link_map *l = GL(dl_ns)[ns]._ns_loaded; l != NULL; l = l->l_next)
@@ -278,7 +290,7 @@ _dl_close (void *_map)
 	  if (imap->l_searchlist.r_list == NULL
 	      && imap->l_initfini != NULL)
 	    {
-	      /* The object is still used.  But the object we are
+	      /* The object is still used.  But one of the objects we are
 		 unloading right now is responsible for loading it.  If
 		 the current object does not have it's own scope yet we
 		 have to create one.  This has to be done before running
@@ -294,15 +306,27 @@ _dl_close (void *_map)
 	      imap->l_searchlist.r_nlist = cnt;
 
 	      for (cnt = 0; imap->l_scope[cnt] != NULL; ++cnt)
-		if (imap->l_scope[cnt] == &map->l_searchlist)
+		/* This relies on l_scope[] entries being always set either
+		   to its own l_symbolic_searchlist address, or some other map's
+		   l_searchlist address.  */
+		if (imap->l_scope[cnt] != &imap->l_symbolic_searchlist)
 		  {
-		    imap->l_scope[cnt] = &imap->l_searchlist;
-		    break;
+		    struct link_map *tmap;
+
+		    tmap = (struct link_map *) ((char *) imap->l_scope[cnt]
+						- offsetof (struct link_map,
+							    l_searchlist));
+		    assert (tmap->l_ns == ns);
+		    if (tmap->l_idx != -1)
+		      {
+			imap->l_scope[cnt] = &imap->l_searchlist;
+			break;
+		      }
 		  }
 	    }
 
 	  /* The loader is gone, so mark the object as not having one.
-	     Note: l_idx == -1 -> object will be removed.  */
+	     Note: l_idx != -1 -> object will be removed.  */
 	  if (imap->l_loader != NULL && imap->l_loader->l_idx != -1)
 	    imap->l_loader = NULL;
 
@@ -514,8 +538,12 @@ _dl_close (void *_map)
   _r_debug.r_state = RT_CONSISTENT;
   GLRO(dl_debug_state) ();
 
-  /* Release the lock.  */
+  /* Recheck if we need to retry, release the lock.  */
  out:
+  if (dl_close_state == rerun)
+    goto retry;
+
+  dl_close_state = not_pending;
   __rtld_lock_unlock_recursive (GL(dl_load_lock));
 }
 libc_hidden_def (_dl_close)
@@ -586,7 +614,7 @@ libc_freeres_fn (free_mem)
 	free_slotinfo (&GL(dl_tls_dtv_slotinfo_list));
       else
 # endif
-        /* The first element of the list does not have to be deallocated.
+	/* The first element of the list does not have to be deallocated.
 	   It was allocated in the dynamic linker (i.e., with a different
 	   malloc), and in the static library it's in .bss space.  */
 	free_slotinfo (&GL(dl_tls_dtv_slotinfo_list)->next);

elf/unload6.c

@@ -0,0 +1,30 @@
+#include <dlfcn.h>
+#include <stdio.h>
+
+int
+main (void)
+{
+  void *h = dlopen ("unload6mod1.so", RTLD_LAZY);
+  if (h == NULL)
+    {
+      puts ("dlopen unload6mod1.so failed");
+      return 1;
+    }
+
+  int (*fn) (int);
+  fn = dlsym (h, "foo");
+  if (fn == NULL)
+    {
+      puts ("dlsym failed");
+      return 1;
+    }
+
+  int val = fn (16);
+  if (val != 24)
+    {
+      printf ("foo returned %d != 24\n", val);
+      return 1;
+    }
+
+  return 0;
+}

elf/unload6mod1.c

@@ -0,0 +1,16 @@
+#include <dlfcn.h>
+#include <stdio.h>
+
+int
+foo (int i)
+{
+  void *h = dlopen ("unload6mod2.so", RTLD_LAZY);
+  if (h == NULL)
+    {
+      puts ("dlopen unload6mod2.so failed");
+      return 1;
+    }
+
+  dlclose (h);
+  return i + 8;
+}

elf/unload6mod2.c

@@ -0,0 +1,23 @@
+#include <dlfcn.h>
+#include <stdio.h>
+#include <unistd.h>
+
+static void *h;
+
+static void __attribute__((constructor))
+mod2init (void)
+{
+  h = dlopen ("unload6mod3.so", RTLD_LAZY);
+  if (h == NULL)
+    {
+      puts ("dlopen unload6mod3.so failed");
+      fflush (stdout);
+      _exit (1);
+    }
+}
+
+static void __attribute__((destructor))
+mod2fini (void)
+{
+  dlclose (h);
+}

elf/unload6mod3.c

@@ -0,0 +1,23 @@
+#include <dlfcn.h>
+#include <stdio.h>
+#include <unistd.h>
+
+static void *h;
+
+static void __attribute__((constructor))
+mod3init (void)
+{
+  h = dlopen ("unload6mod1.so", RTLD_LAZY);
+  if (h == NULL)
+    {
+      puts ("dlopen unload6mod1.so failed");
+      fflush (stdout);
+      _exit (1);
+    }
+}
+
+static void __attribute__((destructor))
+mod3fini (void)
+{
+  dlclose (h);
+}