source3/smbd/notifyd/notifyd_entry.c

   1 /*
   2  * This program is free software; you can redistribute it and/or modify
   3  * it under the terms of the GNU General Public License as published by
   4  * the Free Software Foundation; either version 3 of the License, or
   5  * (at your option) any later version.
   6  *
   7  * This program is distributed in the hope that it will be useful,
   8  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10  * GNU General Public License for more details.
  11  *
  12  * You should have received a copy of the GNU General Public License
  13  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  14  */
  15
  16 #include "replace.h"
  17 #include "lib/util/debug.h"
  18 #include "notifyd_private.h"
  19
  20 /*
  21  * Parse an entry in the notifyd_context->entries database
  22  */
  23
  24 /**
  25  * @brief Parse a notifyd database entry.
  26  *
  27  * The memory we pass down needs to be aligned. If it isn't aligned we can run
  28  * into obscure errors as we just point into the data buffer.
  29  *
  30  * @param data The data to parse
  31  * @param data_len The length of the data to parse
  32  * @param watcher A pointer to store the watcher data or NULL.
  33  * @param instances A pointer to store the array of notify instances or NULL.
  34  * @param pnum_instances The number of elements in the array. If you just want
  35  * the number of elements pass NULL for the watcher and instances pointers.
  36  *
  37  * @return true on success, false if an error occurred.
  38  */
  39 bool notifyd_parse_entry(uint8_t *data,
  40                          size_t data_len,
  41                          struct notifyd_watcher *watcher,
  42                          struct notifyd_instance **instances,
  43                          size_t *pnum_instances)
  44 {
  45         size_t ilen;
  46
  47         if (data_len < sizeof(struct notifyd_watcher)) {
  48                 return false;
  49         }
  50
  51         if (watcher != NULL) {
  52                 *watcher = *((struct notifyd_watcher *)(uintptr_t)data);
  53         }
  54
  55         ilen = data_len - sizeof(struct notifyd_watcher);
  56         if ((ilen % sizeof(struct notifyd_instance)) != 0) {
  57                 return false;
  58         }
  59
  60         if (pnum_instances != NULL) {
  61                 *pnum_instances = ilen / sizeof(struct notifyd_instance);
  62         }
  63         if (instances != NULL) {
  64                 /* The (uintptr_t) cast removes a warning from -Wcast-align. */
  65                 *instances =
  66                         (struct notifyd_instance *)(uintptr_t)
  67                                 (data + sizeof(struct notifyd_watcher));
  68         }
  69
  70         return true;
  71 }