ctdb/common/pidfile.c

   1 /*
   2    Create and remove pidfile
   3
   4    Copyright (C) Amitay Isaacs  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 "system/filesys.h"
  22
  23 #include <talloc.h>
  24
  25 #include "lib/util/blocking.h"
  26 #include "lib/util/pidfile.h"
  27
  28 #include "common/pidfile.h"
  29
  30 struct pidfile_context {
  31         const char *pidfile;
  32         int fd;
  33         pid_t pid;
  34 };
  35
  36 static int pidfile_context_destructor(struct pidfile_context *pid_ctx);
  37
  38 int pidfile_context_create(TALLOC_CTX *mem_ctx, const char *pidfile,
  39                            struct pidfile_context **result)
  40 {
  41         struct pidfile_context *pid_ctx;
  42         int fd, ret = 0;
  43
  44         pid_ctx = talloc_zero(mem_ctx, struct pidfile_context);
  45         if (pid_ctx == NULL) {
  46                 return ENOMEM;
  47         }
  48
  49         pid_ctx->pidfile = talloc_strdup(pid_ctx, pidfile);
  50         if (pid_ctx->pidfile == NULL) {
  51                 ret = ENOMEM;
  52                 goto fail;
  53         }
  54
  55         pid_ctx->pid = getpid();
  56
  57         ret = pidfile_path_create(pid_ctx->pidfile, &fd);
  58         if (ret != 0) {
  59                 return ret;
  60         }
  61
  62         pid_ctx->fd = fd;
  63
  64         talloc_set_destructor(pid_ctx, pidfile_context_destructor);
  65
  66         *result = pid_ctx;
  67         return 0;
  68
  69 fail:
  70         talloc_free(pid_ctx);
  71         return ret;
  72 }
  73
  74 static int pidfile_context_destructor(struct pidfile_context *pid_ctx)
  75 {
  76         if (getpid() != pid_ctx->pid) {
  77                 return 0;
  78         }
  79
  80         (void) unlink(pid_ctx->pidfile);
  81
  82         pidfile_fd_close(pid_ctx->fd);
  83
  84         return 0;
  85 }