source3/lib/messages_ctdb_ref.c

   1 /*
   2  * Unix SMB/CIFS implementation.
   3  * Samba internal messaging functions
   4  * Copyright (C) 2017 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_ctdb.h"
  23 #include "messages_ctdb_ref.h"
  24 #include "lib/util/debug.h"
  25 #include "lib/util/dlinklist.h"
  26
  27 struct msg_ctdb_ref {
  28         struct msg_ctdb_ref *prev, *next;
  29         struct messaging_ctdb_fde *fde;
  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 ctdb_pid = 0;
  37 static struct msg_ctdb_ref *refs = NULL;
  38
  39 static int msg_ctdb_ref_destructor(struct msg_ctdb_ref *r);
  40 static void msg_ctdb_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_ctdb_ref(TALLOC_CTX *mem_ctx, struct tevent_context *ev,
  45                          const char *sockname, int timeout, uint64_t unique_id,
  46                          void (*recv_cb)(struct tevent_context *ev,
  47                                          const uint8_t *msg, size_t msg_len,
  48                                          int *fds, size_t num_fds,
  49                                          void *private_data),
  50                          void *recv_cb_private_data,
  51                          int *err)
  52 {
  53         struct msg_ctdb_ref *result, *tmp_refs;
  54
  55         result = talloc(mem_ctx, struct msg_ctdb_ref);
  56         if (result == NULL) {
  57                 *err = ENOMEM;
  58                 return NULL;
  59         }
  60         result->fde = NULL;
  61
  62         tmp_refs = refs;
  63
  64         if ((refs != NULL) && (ctdb_pid != tevent_cached_getpid())) {
  65                 /*
  66                  * Have to reinit after fork
  67                  */
  68                 messaging_ctdb_destroy();
  69                 refs = NULL;
  70         }
  71
  72         if (refs == NULL) {
  73                 int ret;
  74
  75                 ret = messaging_ctdb_init(sockname, timeout, unique_id,
  76                                           msg_ctdb_ref_recv, NULL);
  77                 DBG_DEBUG("messaging_ctdb_init returned %s\n", strerror(ret));
  78                 if (ret != 0) {
  79                         DEBUG(10, ("messaging_ctdb_init failed: %s\n",
  80                                    strerror(ret)));
  81                         TALLOC_FREE(result);
  82                         *err = ret;
  83                         return NULL;
  84                 }
  85                 ctdb_pid = tevent_cached_getpid();
  86         }
  87
  88         result->fde = messaging_ctdb_register_tevent_context(result, ev);
  89         if (result->fde == NULL) {
  90                 TALLOC_FREE(result);
  91                 *err = ENOMEM;
  92                 return NULL;
  93         }
  94
  95         refs = tmp_refs;
  96
  97         result->recv_cb = recv_cb;
  98         result->recv_cb_private_data = recv_cb_private_data;
  99         DLIST_ADD(refs, result);
 100         talloc_set_destructor(result, msg_ctdb_ref_destructor);
 101
 102         return result;
 103 }
 104
 105 static void msg_ctdb_ref_recv(struct tevent_context *ev,
 106                               const uint8_t *msg, size_t msg_len,
 107                               int *fds, size_t num_fds, void *private_data)
 108 {
 109         struct msg_ctdb_ref *r, *next;
 110
 111         for (r = refs; r != NULL; r = next) {
 112                 bool active;
 113
 114                 next = r->next;
 115
 116                 active = messaging_ctdb_fde_active(r->fde);
 117                 if (!active) {
 118                         /*
 119                          * r's tevent_context has died.
 120                          */
 121                         continue;
 122                 }
 123
 124                 r->recv_cb(ev, msg, msg_len, fds, num_fds,
 125                            r->recv_cb_private_data);
 126                 break;
 127         }
 128 }
 129
 130 static int msg_ctdb_ref_destructor(struct msg_ctdb_ref *r)
 131 {
 132         if (refs == NULL) {
 133                 abort();
 134         }
 135         DLIST_REMOVE(refs, r);
 136
 137         TALLOC_FREE(r->fde);
 138
 139         DBG_DEBUG("refs=%p\n", refs);
 140
 141         if (refs == NULL) {
 142                 messaging_ctdb_destroy();
 143         }
 144         return 0;
 145 }