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 "replace.h"
  21 #include <talloc.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         struct tevent_fd *tevent_handle;
  30         void (*recv_cb)(struct tevent_context *ev,
  31                         const uint8_t *msg, size_t msg_len,
  32                         int *fds, size_t num_fds, void *private_data);
  33         void *recv_cb_private_data;
  34 };
  35
  36 static pid_t dgm_pid = 0;
  37 static struct msg_dgm_ref *refs = NULL;
  38
  39 static int msg_dgm_ref_destructor(struct msg_dgm_ref *r);
  40 static void msg_dgm_ref_recv(struct tevent_context *ev,
  41                              const uint8_t *msg, size_t msg_len,
  42                              int *fds, size_t num_fds, void *private_data);
  43
  44 void *messaging_dgm_ref(TALLOC_CTX *mem_ctx, struct tevent_context *ev,
  45                         uint64_t *unique,
  46                         const char *socket_dir,
  47                         const char *lockfile_dir,
  48                         void (*recv_cb)(struct tevent_context *ev,
  49                                         const uint8_t *msg, size_t msg_len,
  50                                         int *fds, size_t num_fds,
  51                                         void *private_data),
  52                         void *recv_cb_private_data,
  53                         int *err)
  54 {
  55         struct msg_dgm_ref *result, *tmp_refs;
  56
  57         result = talloc(mem_ctx, struct msg_dgm_ref);
  58         if (result == NULL) {
  59                 *err = ENOMEM;
  60                 return NULL;
  61         }
  62         result->tevent_handle = NULL;
  63
  64         tmp_refs = refs;
  65
  66         if ((refs != NULL) && (dgm_pid != getpid())) {
  67                 /*
  68                  * Have to reinit after fork
  69                  */
  70                 messaging_dgm_destroy();
  71                 refs = NULL;
  72         }
  73
  74         if (refs == NULL) {
  75                 int ret;
  76
  77                 ret = messaging_dgm_init(ev, unique, socket_dir, lockfile_dir,
  78                                          msg_dgm_ref_recv, NULL);
  79                 DBG_DEBUG("messaging_dgm_init returned %s\n", strerror(ret));
  80                 if (ret != 0) {
  81                         DEBUG(10, ("messaging_dgm_init failed: %s\n",
  82                                    strerror(ret)));
  83                         TALLOC_FREE(result);
  84                         *err = ret;
  85                         return NULL;
  86                 }
  87                 dgm_pid = getpid();
  88         } else {
  89                 int ret;
  90                 ret = messaging_dgm_get_unique(getpid(), unique);
  91                 DBG_DEBUG("messaging_dgm_get_unique returned %s\n",
  92                           strerror(ret));
  93                 if (ret != 0) {
  94                         TALLOC_FREE(result);
  95                         *err = ret;
  96                         return NULL;
  97                 }
  98
  99         }
 100
 101         result->tevent_handle = messaging_dgm_register_tevent_context(
 102                 result, ev);
 103         if (result->tevent_handle == NULL) {
 104                 TALLOC_FREE(result);
 105                 *err = ENOMEM;
 106                 return NULL;
 107         }
 108
 109         DBG_DEBUG("unique = %"PRIu64"\n", *unique);
 110
 111         refs = tmp_refs;
 112
 113         result->recv_cb = recv_cb;
 114         result->recv_cb_private_data = recv_cb_private_data;
 115         DLIST_ADD(refs, result);
 116         talloc_set_destructor(result, msg_dgm_ref_destructor);
 117
 118         return result;
 119 }
 120
 121 static void msg_dgm_ref_recv(struct tevent_context *ev,
 122                              const uint8_t *msg, size_t msg_len,
 123                              int *fds, size_t num_fds, void *private_data)
 124 {
 125         struct msg_dgm_ref *r, *next;
 126
 127         /*
 128          * We have to broadcast incoming messages to all refs. The first ref
 129          * that grabs the fd's will get them.
 130          */
 131         for (r = refs; r != NULL; r = next) {
 132                 next = r->next;
 133                 r->recv_cb(ev, msg, msg_len, fds, num_fds,
 134                            r->recv_cb_private_data);
 135         }
 136 }
 137
 138 static int msg_dgm_ref_destructor(struct msg_dgm_ref *r)
 139 {
 140         if (refs == NULL) {
 141                 abort();
 142         }
 143         DLIST_REMOVE(refs, r);
 144
 145         TALLOC_FREE(r->tevent_handle);
 146
 147         DBG_DEBUG("refs=%p\n", refs);
 148
 149         if (refs == NULL) {
 150                 messaging_dgm_destroy();
 151         }
 152         return 0;
 153 }