source3/lib/server_id_watch.c

   1 /*
   2  * Unix SMB/CIFS implementation.
   3  * Wait for process death
   4  * Copyright (C) Volker Lendecke 2016
   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 <tevent.h>
  22 #include <talloc.h>
  23 #include "serverid.h"
  24 #include "server_id_watch.h"
  25 #include "lib/util/tevent_unix.h"
  26
  27 struct server_id_watch_state {
  28         struct tevent_context *ev;
  29         struct server_id pid;
  30 };
  31
  32 static void server_id_watch_waited(struct tevent_req *subreq);
  33
  34 struct tevent_req *server_id_watch_send(TALLOC_CTX *mem_ctx,
  35                                         struct tevent_context *ev,
  36                                         struct server_id pid)
  37 {
  38         struct tevent_req *req, *subreq;
  39         struct server_id_watch_state *state;
  40
  41         req = tevent_req_create(mem_ctx, &state, struct server_id_watch_state);
  42         if (req == NULL) {
  43                 return NULL;
  44         }
  45         state->ev = ev;
  46         state->pid = pid;
  47
  48         if (!serverid_exists(&state->pid)) {
  49                 tevent_req_done(req);
  50                 return tevent_req_post(req, ev);
  51         }
  52
  53         subreq = tevent_wakeup_send(
  54                 state, ev, tevent_timeval_current_ofs(0, 500000));
  55         if (tevent_req_nomem(subreq, req)) {
  56                 return tevent_req_post(req, ev);
  57         }
  58         tevent_req_set_callback(subreq, server_id_watch_waited, req);
  59
  60         return req;
  61 }
  62
  63 static void server_id_watch_waited(struct tevent_req *subreq)
  64 {
  65         struct tevent_req *req = tevent_req_callback_data(
  66                 subreq, struct tevent_req);
  67         struct server_id_watch_state *state = tevent_req_data(
  68                 req, struct server_id_watch_state);
  69         bool ok;
  70
  71         ok = tevent_wakeup_recv(subreq);
  72         TALLOC_FREE(subreq);
  73         if (!ok) {
  74                 tevent_req_oom(req);
  75                 return;
  76         }
  77
  78         if (!serverid_exists(&state->pid)) {
  79                 tevent_req_done(req);
  80                 return;
  81         }
  82
  83         subreq = tevent_wakeup_send(
  84                 state, state->ev, tevent_timeval_current_ofs(0, 500000));
  85         if (tevent_req_nomem(subreq, req)) {
  86                 return;
  87         }
  88         tevent_req_set_callback(subreq, server_id_watch_waited, req);
  89 }
  90
  91 int server_id_watch_recv(struct tevent_req *req, struct server_id *pid)
  92 {
  93         struct server_id_watch_state *state = tevent_req_data(
  94                 req, struct server_id_watch_state);
  95         int err;
  96
  97         if (tevent_req_is_unix_error(req, &err)) {
  98                 return err;
  99         }
 100         if (pid) {
 101                 *pid = state->pid;
 102         }
 103         return 0;
 104 }