Fix bug 5686 - libsmbclient segfaults with more than one SMBCCTX.

Here is a patch to allow many subsystems to be re-initialized. The only
functional change I made was to remove the null context tracking, as the memory
allocated here is designed to be left for the complete lifetime of the program.
Freeing this early (when all smb contexts are destroyed) could crash other
users of talloc.
Jeremy.
(This used to be commit 8c630ef)

examples/libsmbclient/Makefile

@@ -94,6 +94,10 @@ testwrite: testwrite.o
 	@echo Linking testwrite
 	$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $< $(LIBSMBCLIENT) -lpopt
 
+testctx: testctx.o
+	@echo Linking testctx
+	$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $< $(LIBSMBCLIENT) -lpopt
+
 smbsh:
 	make -C smbwrapper
 

examples/libsmbclient/testctx.c

@@ -0,0 +1,17 @@
+#include <libsmbclient.h>
+
+void create_and_destroy_context (void)
+{
+  SMBCCTX *ctx;
+  ctx = smbc_new_context ();
+  smbc_init_context (ctx);
+
+  smbc_free_context (ctx, 1);
+}
+
+int main (int argc, char **argv)
+{
+  create_and_destroy_context ();
+  create_and_destroy_context ();
+  return 0;
+}

source3/lib/charcnv.c

@@ -47,6 +47,7 @@ char lp_failed_convert_char(void)
 
 static smb_iconv_t conv_handles[NUM_CHARSETS][NUM_CHARSETS];
 static bool conv_silent; /* Should we do a debug if the conversion fails ? */
+static bool initialized;
 
 /**
  * Return the name of a charset to give to iconv().
@@ -92,12 +93,10 @@ static const char *charset_name(charset_t ch)
 
 void lazy_initialize_conv(void)
 {
-	static int initialized = False;
-
 	if (!initialized) {
-		initialized = True;
 		load_case_tables();
 		init_iconv();
+		initialized = true;
 	}
 }
 
@@ -116,6 +115,7 @@ void gfree_charcnv(void)
 			}
 		}
 	}
+	initialized = false;
 }
 
 /**

source3/lib/debug.c

@@ -94,7 +94,7 @@ static TALLOC_CTX *tmp_debug_ctx;
 
 /*
  * This is to allow assignment to DEBUGLEVEL before the debug
- * system has been initialised.
+ * system has been initialized.
  */
 static int debug_all_class_hack = 1;
 static bool debug_all_class_isset_hack = True;
@@ -183,6 +183,8 @@ static char **classname_table = NULL;
  Free memory pointed to by global pointers.
 ****************************************************************************/
 
+static bool initialized;
+
 void gfree_debugsyms(void)
 {
 	int i;
@@ -194,13 +196,23 @@ void gfree_debugsyms(void)
 		SAFE_FREE( classname_table );
 	}
 
-	if ( DEBUGLEVEL_CLASS != &debug_all_class_hack )
+	if ( DEBUGLEVEL_CLASS != &debug_all_class_hack ) {
 		SAFE_FREE( DEBUGLEVEL_CLASS );
+		DEBUGLEVEL_CLASS = &debug_all_class_hack;
+	}
 
-	if ( DEBUGLEVEL_CLASS_ISSET != &debug_all_class_isset_hack )
+	if ( DEBUGLEVEL_CLASS_ISSET != &debug_all_class_isset_hack ) {
 		SAFE_FREE( DEBUGLEVEL_CLASS_ISSET );
+		DEBUGLEVEL_CLASS_ISSET = &debug_all_class_isset_hack;
+	}
 
 	SAFE_FREE(format_bufr);
+
+	debug_num_classes = 0;
+
+	debug_level = DEBUGLEVEL_CLASS;
+
+	initialized = false;
 }
 
 /****************************************************************************
@@ -530,13 +542,12 @@ Init debugging (one time stuff)
 
 void debug_init(void)
 {
-	static bool initialised = False;
 	const char **p;
 
-	if (initialised)
+	if (initialized)
 		return;
 
-	initialised = True;
+	initialized = true;
 
 	for(p = default_classname_table; *p; p++) {
 		debug_add_class(*p);

source3/lib/util.c

@@ -189,12 +189,9 @@ void gfree_all( void )
 	gfree_names();
 	gfree_loadparm();
 	gfree_case_tables();
-	gfree_debugsyms();
 	gfree_charcnv();
 	gfree_interfaces();
-
-	/* release the talloc null_context memory last */
-	talloc_disable_null_tracking();
+	gfree_debugsyms();
 }
 
 const char *my_netbios_names(int i)

source3/lib/util_unistr.c

@@ -33,6 +33,7 @@ static uint8 *valid_table;
 static bool upcase_table_use_unmap;
 static bool lowcase_table_use_unmap;
 static bool valid_table_use_unmap;
+static bool initialized;
 
 /**
  * Destroy global objects allocated by load_case_tables()
@@ -59,6 +60,7 @@ void gfree_case_tables(void)
 		else
 			SAFE_FREE(valid_table);
 	}
+	initialized = false;
 }
 
 /**
@@ -70,15 +72,14 @@ void gfree_case_tables(void)
 
 void load_case_tables(void)
 {
-	static int initialised;
 	char *old_locale = NULL, *saved_locale = NULL;
 	int i;
 	TALLOC_CTX *frame = NULL;
 
-	if (initialised) {
+	if (initialized) {
 		return;
 	}
-	initialised = 1;
+	initialized = true;
 
 	frame = talloc_stackframe();
 

source3/libsmb/libsmb_context.c

@@ -30,9 +30,8 @@
 /*
  * Is the logging working / configfile read ? 
  */
-static int SMBC_initialized = 0;
-
-
+static bool SMBC_initialized;
+static unsigned int initialized_ctx_count;
 
 /*
  * Get a new empty handle to fill in with your own info
@@ -201,22 +200,19 @@ smbc_free_context(SMBCCTX *context,
 
         DEBUG(3, ("Context %p successfully freed\n", context));
 
-	gfree_names();
-	gfree_loadparm();
-	gfree_case_tables();
-	gfree_charcnv();
-	gfree_interfaces();
-
-	gencache_shutdown();
-	secrets_shutdown();
-
-	/* release the talloc null_context memory last */
-	talloc_disable_null_tracking();
+	SAFE_FREE(context->internal);
+        SAFE_FREE(context);
 
-	gfree_debugsyms();
+	if (initialized_ctx_count) {
+		initialized_ctx_count--;
+	}
 
-        SAFE_FREE(context->internal);
-        SAFE_FREE(context);
+	if (initialized_ctx_count == 0 && SMBC_initialized) {
+		gencache_shutdown();
+		secrets_shutdown();
+		gfree_all();
+		SMBC_initialized = false;
+	}
         return 0;
 }
 
@@ -427,9 +423,6 @@ smbc_init_context(SMBCCTX *context)
         char *user = NULL;
         char *home = NULL;
 
-        /* track talloc null_context memory */
-        talloc_enable_null_tracking();
-
         if (!context) {
                 errno = EBADF;
                 return NULL;
@@ -527,7 +520,7 @@ smbc_init_context(SMBCCTX *context)
                 BlockSignals(True, SIGPIPE);
 
                 /* Done with one-time initialisation */
-                SMBC_initialized = 1;
+                SMBC_initialized = true;
 
                 TALLOC_FREE(frame);
         }
@@ -616,7 +609,8 @@ smbc_init_context(SMBCCTX *context)
          */
 
         context->internal->initialized = True;
-
+	initialized_ctx_count++;
+
         return context;
 }
 

source3/param/loadparm.c

@@ -8693,6 +8693,7 @@ void gfree_loadparm(void)
 		SAFE_FREE( f );
 		f = next;
 	}
+	file_lists = NULL;
 
 	/* Free resources allocated to services */