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 "lib/util/util_paths.h"
  26 #include "system/filesys.h"
  27 #include "system/dir.h"
  28
  29 /**
  30  * Obtain the init function from a shared library file
  31  */
  32 init_module_fn load_module(const char *path, bool is_probe, void **handle_out)
  33 {
  34         void *handle;
  35         void *init_fn;
  36         char *error;
  37
  38         /* This should be a WAF build, where modules should be built
  39          * with no undefined symbols and are already linked against
  40          * the libraries that they are loaded by */
  41         handle = dlopen(path, RTLD_NOW);
  42
  43         /* This call should reset any possible non-fatal errors that
  44            occurred since last call to dl* functions */
  45         error = dlerror();
  46
  47         if (handle == NULL) {
  48                 int level = is_probe ? 5 : 0;
  49                 DEBUG(level, ("Error loading module '%s': %s\n", path, error ? error : ""));
  50                 return NULL;
  51         }
  52
  53         init_fn = (init_module_fn)dlsym(handle, SAMBA_INIT_MODULE);
  54
  55         /* we could check dlerror() to determine if it worked, because
  56            dlsym() can validly return NULL, but what would we do with
  57            a NULL pointer as a module init function? */
  58
  59         if (init_fn == NULL) {
  60                 DEBUG(0, ("Unable to find %s() in %s: %s\n",
  61                           SAMBA_INIT_MODULE, path, dlerror()));
  62                 DEBUG(1, ("Loading module '%s' failed\n", path));
  63                 dlclose(handle);
  64                 return NULL;
  65         }
  66
  67         if (handle_out) {
  68                 *handle_out = handle;
  69         }
  70
  71         return (init_module_fn)init_fn;
  72 }
  73
  74 /**
  75  * Obtain list of init functions from the modules in the specified
  76  * directory
  77  */
  78 static init_module_fn *load_modules(TALLOC_CTX *mem_ctx, const char *path)
  79 {
  80         DIR *dir;
  81         struct dirent *entry;
  82         char *filename;
  83         int success = 0;
  84         init_module_fn *ret = talloc_array(mem_ctx, init_module_fn, 2);
  85
  86         ret[0] = NULL;
  87
  88         dir = opendir(path);
  89         if (dir == NULL) {
  90                 talloc_free(ret);
  91                 return NULL;
  92         }
  93
  94         while((entry = readdir(dir))) {
  95                 if (ISDOT(entry->d_name) || ISDOTDOT(entry->d_name))
  96                         continue;
  97
  98                 filename = talloc_asprintf(mem_ctx, "%s/%s", path, entry->d_name);
  99
 100                 ret[success] = load_module(filename, true, NULL);
 101                 if (ret[success]) {
 102                         ret = talloc_realloc(mem_ctx, ret, init_module_fn, success+2);
 103                         success++;
 104                         ret[success] = NULL;
 105                 }
 106
 107                 talloc_free(filename);
 108         }
 109
 110         closedir(dir);
 111
 112         return ret;
 113 }
 114
 115 /**
 116  * Run the specified init functions.
 117  *
 118  * @return true if all functions ran successfully, false otherwise
 119  */
 120 bool run_init_functions(TALLOC_CTX *ctx, init_module_fn *fns)
 121 {
 122         int i;
 123         bool ret = true;
 124
 125         if (fns == NULL)
 126                 return true;
 127
 128         for (i = 0; fns[i]; i++) { ret &= (bool)NT_STATUS_IS_OK(fns[i](ctx)); }
 129
 130         return ret;
 131 }
 132
 133 /**
 134  * Load the initialization functions from DSO files for a specific subsystem.
 135  *
 136  * Will return an array of function pointers to initialization functions
 137  */
 138
 139 init_module_fn *load_samba_modules(TALLOC_CTX *mem_ctx, const char *subsystem)
 140 {
 141         char *path = modules_path(mem_ctx, subsystem);
 142         init_module_fn *ret;
 143
 144         ret = load_modules(mem_ctx, path);
 145
 146         talloc_free(path);
 147
 148         return ret;
 149 }
 150
 151 static NTSTATUS load_module_absolute_path(const char *module_path,
 152                                           bool is_probe)
 153 {
 154         void *handle;
 155         init_module_fn init;
 156         NTSTATUS status;
 157
 158         DBG_INFO("%s module '%s'\n",
 159                  is_probe ? "Probing" : "Loading",
 160                  module_path);
 161
 162         init = load_module(module_path, is_probe, &handle);
 163         if (init == NULL) {
 164                 return NT_STATUS_UNSUCCESSFUL;
 165         }
 166
 167         DBG_NOTICE("Module '%s' loaded\n", module_path);
 168
 169         status = init(NULL);
 170         if (!NT_STATUS_IS_OK(status)) {
 171                 DBG_ERR("Module '%s' initialization failed: %s\n",
 172                         module_path,
 173                         get_friendly_nt_error_msg(status));
 174                 dlclose(handle);
 175                 return status;
 176         }
 177
 178         return NT_STATUS_OK;
 179 }
 180
 181 /* Load all modules in list and return number of
 182  * modules that has been successfully loaded */
 183 int smb_load_all_modules_absoute_path(const char **modules)
 184 {
 185         int i;
 186         int success = 0;
 187
 188         for(i = 0; modules[i] != NULL; i++) {
 189                 const char *module = modules[i];
 190                 NTSTATUS status;
 191
 192                 if (module[0] != '/') {
 193                         continue;
 194                 }
 195
 196                 status = load_module_absolute_path(module, false);
 197                 if (NT_STATUS_IS_OK(status)) {
 198                         success++;
 199                 }
 200         }
 201
 202         DEBUG(2, ("%d modules successfully loaded\n", success));
 203
 204         return success;
 205 }
 206
 207 /**
 208  * @brief Check if a module exist and load it.
 209  *
 210  * @param[in]  subsystem  The name of the subsystem the module belongs too.
 211  *
 212  * @param[in]  module     The name of the module
 213  *
 214  * @return  A NTSTATUS code
 215  */
 216 NTSTATUS smb_probe_module(const char *subsystem, const char *module)
 217 {
 218         NTSTATUS status;
 219         char *module_path = NULL;
 220         TALLOC_CTX *tmp_ctx = talloc_stackframe();
 221
 222         if (subsystem == NULL) {
 223                 status = NT_STATUS_INVALID_PARAMETER;
 224                 goto done;
 225         }
 226         if (module == NULL) {
 227                 status = NT_STATUS_INVALID_PARAMETER;
 228                 goto done;
 229         }
 230
 231         if (strchr(module, '/')) {
 232                 status = NT_STATUS_INVALID_PARAMETER;
 233                 goto done;
 234         }
 235
 236         module_path = talloc_asprintf(tmp_ctx,
 237                                       "%s/%s.%s",
 238                                       modules_path(tmp_ctx, subsystem),
 239                                       module,
 240                                       shlib_ext());
 241         if (module_path == NULL) {
 242                 status = NT_STATUS_NO_MEMORY;
 243                 goto done;
 244         }
 245
 246         status = load_module_absolute_path(module_path, true);
 247
 248 done:
 249         TALLOC_FREE(tmp_ctx);
 250         return status;
 251 }
 252
 253 /**
 254  * @brief Check if a module exist and load it.
 255  *
 256  * Warning: Using this function can have security implecations!
 257  *
 258  * @param[in]  subsystem  The name of the subsystem the module belongs too.
 259  *
 260  * @param[in]  module     Load a module using an absolute path.
 261  *
 262  * @return  A NTSTATUS code
 263  */
 264 NTSTATUS smb_probe_module_absolute_path(const char *module)
 265 {
 266         if (module == NULL) {
 267                 return NT_STATUS_INVALID_PARAMETER;
 268         }
 269         if (module[0] != '/') {
 270                 return NT_STATUS_INVALID_PARAMETER;
 271         }
 272
 273         return load_module_absolute_path(module, true);
 274 }
 275
 276 /**
 277  * @brief Load a module.
 278  *
 279  * @param[in]  subsystem  The name of the subsystem the module belongs too.
 280  *
 281  * @param[in]  module     Check if a module exists and load it.
 282  *
 283  * @return  A NTSTATUS code
 284  */
 285 NTSTATUS smb_load_module(const char *subsystem, const char *module)
 286 {
 287         NTSTATUS status;
 288         char *module_path = NULL;
 289         TALLOC_CTX *tmp_ctx = talloc_stackframe();
 290
 291         if (subsystem == NULL) {
 292                 status = NT_STATUS_INVALID_PARAMETER;
 293                 goto done;
 294         }
 295         if (module == NULL) {
 296                 status = NT_STATUS_INVALID_PARAMETER;
 297                 goto done;
 298         }
 299
 300         if (strchr(module, '/')) {
 301                 status = NT_STATUS_INVALID_PARAMETER;
 302                 goto done;
 303         }
 304
 305         module_path = talloc_asprintf(tmp_ctx,
 306                                       "%s/%s.%s",
 307                                       modules_path(tmp_ctx, subsystem),
 308                                       module,
 309                                       shlib_ext());
 310         if (module_path == NULL) {
 311                 status = NT_STATUS_NO_MEMORY;
 312                 goto done;
 313         }
 314
 315         status = load_module_absolute_path(module_path, false);
 316
 317 done:
 318         TALLOC_FREE(tmp_ctx);
 319         return status;
 320 }