source3/lib/messages_dgm_ref.c

   1 /*
   2  * Unix SMB/CIFS implementation.
   3  * Samba internal messaging functions
   4  * Copyright (C) 2014 by Volker Lendecke
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 3 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <talloc.h>
  21 #include "replace.h"
  22 #include "messages_dgm.h"
  23 #include "messages_dgm_ref.h"
  24 #include "lib/util/debug.h"
  25 #include "lib/util/dlinklist.h"
  26
  27 struct msg_dgm_ref {
  28         struct msg_dgm_ref *prev, *next;
  29         void (*recv_cb)(const uint8_t *msg, size_t msg_len,
  30                         int *fds, size_t num_fds, void *private_data);
  31         void *recv_cb_private_data;
  32 };
  33
  34 static pid_t dgm_pid = 0;
  35 static struct msg_dgm_ref *refs = NULL;
  36
  37 static int msg_dgm_ref_destructor(struct msg_dgm_ref *r);
  38 static void msg_dgm_ref_recv(const uint8_t *msg, size_t msg_len,
  39                              int *fds, size_t num_fds, void *private_data);
  40
  41 void *messaging_dgm_ref(TALLOC_CTX *mem_ctx, struct tevent_context *ev,
  42                         uint64_t unique,
  43                         const char *socket_dir,
  44                         const char *lockfile_dir,
  45                         void (*recv_cb)(const uint8_t *msg, size_t msg_len,
  46                                         int *fds, size_t num_fds,
  47                                         void *private_data),
  48                         void *recv_cb_private_data,
  49                         int *err)
  50 {
  51         struct msg_dgm_ref *result, *tmp_refs;
  52
  53         result = talloc(mem_ctx, struct msg_dgm_ref);
  54         if (result == NULL) {
  55                 *err = ENOMEM;
  56                 return NULL;
  57         }
  58
  59         tmp_refs = refs;
  60
  61         if ((refs != NULL) && (dgm_pid != getpid())) {
  62                 /*
  63                  * Have to reinit after fork
  64                  */
  65                 messaging_dgm_destroy();
  66                 refs = NULL;
  67         }
  68
  69         if (refs == NULL) {
  70                 int ret;
  71
  72                 ret = messaging_dgm_init(ev, unique, socket_dir, lockfile_dir,
  73                                          msg_dgm_ref_recv, NULL);
  74                 if (ret != 0) {
  75                         DEBUG(10, ("messaging_dgm_init failed: %s\n",
  76                                    strerror(ret)));
  77                         TALLOC_FREE(result);
  78                         *err = ret;
  79                         return NULL;
  80                 }
  81                 dgm_pid = getpid();
  82         }
  83
  84         refs = tmp_refs;
  85
  86         result->recv_cb = recv_cb;
  87         result->recv_cb_private_data = recv_cb_private_data;
  88         DLIST_ADD(refs, result);
  89         talloc_set_destructor(result, msg_dgm_ref_destructor);
  90
  91         return result;
  92 }
  93
  94 static void msg_dgm_ref_recv(const uint8_t *msg, size_t msg_len,
  95                              int *fds, size_t num_fds, void *private_data)
  96 {
  97         struct msg_dgm_ref *r, *next;
  98
  99         /*
 100          * We have to broadcast incoming messages to all refs. The first ref
 101          * that grabs the fd's will get them.
 102          */
 103         for (r = refs; r != NULL; r = next) {
 104                 next = r->next;
 105                 r->recv_cb(msg, msg_len, fds, num_fds,
 106                            r->recv_cb_private_data);
 107         }
 108 }
 109
 110 static int msg_dgm_ref_destructor(struct msg_dgm_ref *r)
 111 {
 112         if (refs == NULL) {
 113                 abort();
 114         }
 115         DLIST_REMOVE(refs, r);
 116
 117         if (refs == NULL) {
 118                 messaging_dgm_destroy();
 119         }
 120         return 0;
 121 }