lib/util/modules.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Samba utility functions
   4    Copyright (C) Jelmer Vernooij 2002-2003,2005-2007
   5    Copyright (C) Stefan (metze) Metzmacher 2003
   6    Copyright (C) Andrew Bartlett 2011
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20 */
  21
  22 #include "includes.h"
  23 #include "dynconfig/dynconfig.h"
  24 #include "lib/util/samba_modules.h"
  25 #include "system/filesys.h"
  26 #include "system/dir.h"
  27
  28 /**
  29  * Obtain the init function from a shared library file
  30  */
  31 init_module_fn load_module(const char *path, bool is_probe, void **handle_out)
  32 {
  33         void *handle;
  34         void *init_fn;
  35         char *error;
  36
  37         /* This should be a WAF build, where modules should be built
  38          * with no undefined symbols and are already linked against
  39          * the libraries that they are loaded by */
  40         handle = dlopen(path, RTLD_NOW);
  41
  42         /* This call should reset any possible non-fatal errors that
  43            occured since last call to dl* functions */
  44         error = dlerror();
  45
  46         if (handle == NULL) {
  47                 int level = is_probe ? 5 : 0;
  48                 DEBUG(level, ("Error loading module '%s': %s\n", path, error ? error : ""));
  49                 return NULL;
  50         }
  51
  52         init_fn = (init_module_fn)dlsym(handle, SAMBA_INIT_MODULE);
  53
  54         /* we could check dlerror() to determine if it worked, because
  55            dlsym() can validly return NULL, but what would we do with
  56            a NULL pointer as a module init function? */
  57
  58         if (init_fn == NULL) {
  59                 DEBUG(0, ("Unable to find %s() in %s: %s\n",
  60                           SAMBA_INIT_MODULE, path, dlerror()));
  61                 DEBUG(1, ("Loading module '%s' failed\n", path));
  62                 dlclose(handle);
  63                 return NULL;
  64         }
  65
  66         if (handle_out) {
  67                 *handle_out = handle;
  68         }
  69
  70         return (init_module_fn)init_fn;
  71 }
  72
  73 /**
  74  * Obtain list of init functions from the modules in the specified
  75  * directory
  76  */
  77 static init_module_fn *load_modules(TALLOC_CTX *mem_ctx, const char *path)
  78 {
  79         DIR *dir;
  80         struct dirent *entry;
  81         char *filename;
  82         int success = 0;
  83         init_module_fn *ret = talloc_array(mem_ctx, init_module_fn, 2);
  84
  85         ret[0] = NULL;
  86
  87         dir = opendir(path);
  88         if (dir == NULL) {
  89                 talloc_free(ret);
  90                 return NULL;
  91         }
  92
  93         while((entry = readdir(dir))) {
  94                 if (ISDOT(entry->d_name) || ISDOTDOT(entry->d_name))
  95                         continue;
  96
  97                 filename = talloc_asprintf(mem_ctx, "%s/%s", path, entry->d_name);
  98
  99                 ret[success] = load_module(filename, true, NULL);
 100                 if (ret[success]) {
 101                         ret = talloc_realloc(mem_ctx, ret, init_module_fn, success+2);
 102                         success++;
 103                         ret[success] = NULL;
 104                 }
 105
 106                 talloc_free(filename);
 107         }
 108
 109         closedir(dir);
 110
 111         return ret;
 112 }
 113
 114 /**
 115  * Run the specified init functions.
 116  *
 117  * @return true if all functions ran successfully, false otherwise
 118  */
 119 bool run_init_functions(init_module_fn *fns)
 120 {
 121         int i;
 122         bool ret = true;
 123
 124         if (fns == NULL)
 125                 return true;
 126
 127         for (i = 0; fns[i]; i++) { ret &= (bool)NT_STATUS_IS_OK(fns[i]()); }
 128
 129         return ret;
 130 }
 131
 132 /**
 133  * Load the initialization functions from DSO files for a specific subsystem.
 134  *
 135  * Will return an array of function pointers to initialization functions
 136  */
 137
 138 init_module_fn *load_samba_modules(TALLOC_CTX *mem_ctx, const char *subsystem)
 139 {
 140         char *path = modules_path(mem_ctx, subsystem);
 141         init_module_fn *ret;
 142
 143         ret = load_modules(mem_ctx, path);
 144
 145         talloc_free(path);
 146
 147         return ret;
 148 }
 149
 150
 151 /* Load a dynamic module.  Only log a level 0 error if we are not checking
 152    for the existence of a module (probling). */
 153
 154 static NTSTATUS do_smb_load_module(const char *subsystem,
 155                                    const char *module_name, bool is_probe)
 156 {
 157         void *handle;
 158         init_module_fn init;
 159         NTSTATUS status;
 160
 161         char *full_path = NULL;
 162         TALLOC_CTX *ctx = talloc_stackframe();
 163
 164         /* Check for absolute path */
 165
 166         DEBUG(5, ("%s module '%s'\n", is_probe ? "Probing" : "Loading", module_name));
 167
 168         if (subsystem && module_name[0] != '/') {
 169                 full_path = talloc_asprintf(ctx,
 170                                             "%s/%s.%s",
 171                                             modules_path(ctx, subsystem),
 172                                             module_name,
 173                                             shlib_ext());
 174                 if (!full_path) {
 175                         TALLOC_FREE(ctx);
 176                         return NT_STATUS_NO_MEMORY;
 177                 }
 178
 179                 DEBUG(5, ("%s module '%s': Trying to load from %s\n",
 180                           is_probe ? "Probing": "Loading", module_name, full_path));
 181                 init = load_module(full_path, is_probe, &handle);
 182         } else {
 183                 init = load_module(module_name, is_probe, &handle);
 184         }
 185
 186         if (!init) {
 187                 TALLOC_FREE(ctx);
 188                 return NT_STATUS_UNSUCCESSFUL;
 189         }
 190
 191         DEBUG(2, ("Module '%s' loaded\n", module_name));
 192
 193         status = init();
 194         if (!NT_STATUS_IS_OK(status)) {
 195                 DEBUG(0, ("Module '%s' initialization failed: %s\n",
 196                           module_name, get_friendly_nt_error_msg(status)));
 197                 dlclose(handle);
 198         }
 199         TALLOC_FREE(ctx);
 200         return status;
 201 }
 202
 203 /* Load all modules in list and return number of
 204  * modules that has been successfully loaded */
 205 int smb_load_modules(const char **modules)
 206 {
 207         int i;
 208         int success = 0;
 209
 210         for(i = 0; modules[i]; i++){
 211                 if(NT_STATUS_IS_OK(do_smb_load_module(NULL, modules[i], false))) {
 212                         success++;
 213                 }
 214         }
 215
 216         DEBUG(2, ("%d modules successfully loaded\n", success));
 217
 218         return success;
 219 }
 220
 221 NTSTATUS smb_probe_module(const char *subsystem, const char *module)
 222 {
 223         return do_smb_load_module(subsystem, module, true);
 224 }
 225
 226 NTSTATUS smb_load_module(const char *subsystem, const char *module)
 227 {
 228         return do_smb_load_module(subsystem, module, false);
 229 }