s3-module allow libreplace to provide dlopen replacement

[amitay/samba.git] / source3 / lib / module.c

diff --git a/source3/lib/module.c b/source3/lib/module.c
index 2498f6de2c54cbc8681d37a9d0c6ffe72b4ba7bf..9cd3884c517a6403b6659b75588dd9f7665f8fe3 100644 (file)
--- a/source3/lib/module.c
+++ b/source3/lib/module.c
@@ -2,11 +2,12 @@
    Unix SMB/CIFS implementation.
    module loading system
 
-   Copyright (C) Jelmer Vernooij 2002
+   Copyright (C) Jelmer Vernooij 2002-2003
+   Copyright (C) Stefan (metze) Metzmacher 2003
    
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
-   the Free Software Foundation; either version 2 of the License, or
+   the Free Software Foundation; either version 3 of the License, or
    (at your option) any later version.
    
    This program is distributed in the hope that it will be useful,
@@ -15,54 +16,127 @@
    GNU General Public License for more details.
    
    You should have received a copy of the GNU General Public License
-   along with this program; if not, write to the Free Software
-   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
 #include "includes.h"
 
-#ifdef HAVE_DLOPEN
-NTSTATUS smb_load_module(const char *module_name)
+/* Load a dynamic module.  Only log a level 0 error if we are not checking 
+   for the existence of a module (probling). */
+
+static NTSTATUS do_smb_load_module(const char *module_name, bool is_probe)
 {
        void *handle;
        init_module_function *init;
-       NTSTATUS nt_status;
+       NTSTATUS status;
        const char *error;
 
        /* Always try to use LAZY symbol resolving; if the plugin has 
         * backwards compatibility, there might be symbols in the 
         * plugin referencing to old (removed) functions
         */
-       handle = sys_dlopen(module_name, RTLD_LAZY);
+       handle = dlopen(module_name, RTLD_LAZY);
+
+       /* This call should reset any possible non-fatal errors that 
+          occured since last call to dl* functions */
+       error = dlerror();
 
        if(!handle) {
-               DEBUG(0, ("Error loading module '%s': %s\n", module_name, sys_dlerror()));
+               int level = is_probe ? 3 : 0;
+               DEBUG(level, ("Error loading module '%s': %s\n", module_name, error ? error : ""));
                return NT_STATUS_UNSUCCESSFUL;
        }
 
-       init = sys_dlsym(handle, "init_module");
+       init = (init_module_function *)dlsym(handle, "init_samba_module");
 
-       /* we must check sys_dlerror() to determine if it worked, because
-           sys_dlsym() can validly return NULL */
-       error = sys_dlerror();
+       /* we must check dlerror() to determine if it worked, because
+           dlsym() can validly return NULL */
+       error = dlerror();
        if (error) {
-               DEBUG(0, ("Error trying to resolve symbol 'init_module' in %s: %s\n", module_name, error));
+               DEBUG(0, ("Error trying to resolve symbol 'init_samba_module' "
+                         "in %s: %s\n", module_name, error));
+               dlclose(handle);
                return NT_STATUS_UNSUCCESSFUL;
        }
 
-       nt_status = init();
-
        DEBUG(2, ("Module '%s' loaded\n", module_name));
 
-       return nt_status;
-}
+       status = init();
+       if (!NT_STATUS_IS_OK(status)) {
+               DEBUG(0, ("Module '%s' initialization failed: %s\n",
+                           module_name, get_friendly_nt_error_msg(status)));
+               dlclose(handle);
+       }
 
-#else /* HAVE_DLOPEN */
+       return status;
+}
 
 NTSTATUS smb_load_module(const char *module_name)
 {
-       DEBUG(0,("This samba executable has not been build with plugin support"));
-       return NT_STATUS_NOT_SUPPORTED;
+       return do_smb_load_module(module_name, False);
 }
 
-#endif /* HAVE_DLOPEN */
+/* Load all modules in list and return number of
+ * modules that has been successfully loaded */
+int smb_load_modules(const char **modules)
+{
+       int i;
+       int success = 0;
+
+       for(i = 0; modules[i]; i++){
+               if(NT_STATUS_IS_OK(smb_load_module(modules[i]))) {
+                       success++;
+               }
+       }
+
+       DEBUG(2, ("%d modules successfully loaded\n", success));
+
+       return success;
+}
+
+NTSTATUS smb_probe_module(const char *subsystem, const char *module)
+{
+       char *full_path = NULL;
+       TALLOC_CTX *ctx = talloc_stackframe();
+       NTSTATUS status;
+
+       /* Check for absolute path */
+
+       /* if we make any 'samba multibyte string'
+          calls here, we break
+          for loading string modules */
+
+       DEBUG(5, ("Probing module '%s'\n", module));
+
+       if (module[0] == '/') {
+               status = do_smb_load_module(module, True);
+               TALLOC_FREE(ctx);
+               return status;
+       }
+
+       full_path = talloc_asprintf(ctx,
+                                   "%s/%s.%s",
+                                   modules_path(ctx, subsystem),
+                                   module,
+                                   shlib_ext());
+       if (!full_path) {
+               TALLOC_FREE(ctx);
+               return NT_STATUS_NO_MEMORY;
+       }
+
+       DEBUG(5, ("Probing module '%s': Trying to load from %s\n",
+               module, full_path));
+
+       status = do_smb_load_module(full_path, True);
+
+       TALLOC_FREE(ctx);
+       return status;
+}
+
+void init_modules(void)
+{
+       /* FIXME: This can cause undefined symbol errors :
+        *  smb_register_vfs() isn't available in nmbd, for example */
+       if(lp_preload_modules()) 
+               smb_load_modules(lp_preload_modules());
+}