smsd/pidfile.c

   1 /**
   2  * SMSD PID file handling
   3  */
   4 /* Copyright (c) 2009 Michal Cihar <michal@cihar.com> */
   5 /* Licensend under GNU GPL 2 */
   6
   7 #include <stdio.h>
   8 #include <signal.h>
   9 #include <unistd.h>
  10 #include <sys/types.h>
  11 #include <stdlib.h>
  12
  13 #include "pidfile.h"
  14
  15 /**
  16  * Check existing PID file if it points to existing application.
  17  */
  18 void check_pid(const char *pid_file)
  19 {
  20         FILE *file;
  21
  22         int other;
  23
  24         file = fopen(pid_file, "r");
  25         if (file != NULL) {
  26                 if (fscanf(file, "%d", &other) == 1) {
  27                         if (kill(other, 0) == 0) {
  28                                 fprintf(stderr,
  29                                         "Another instance is running, please stop it first!\n");
  30                                 exit(10);
  31                         } else {
  32                                 fprintf(stderr, "Stale lock file, ignoring!\n");
  33                         }
  34                 } else {
  35                         fprintf(stderr, "Can not parse pidfile, ignoring!\n");
  36                 }
  37                 fclose(file);
  38         }
  39 }
  40
  41 /**
  42  * Write a pid file.
  43  */
  44 void write_pid(const char *pid_file)
  45 {
  46         FILE *file;
  47
  48         file = fopen(pid_file, "w");
  49         if (file != NULL) {
  50                 fprintf(file, "%d\n", getpid());
  51                 fclose(file);
  52         } else {
  53                 fprintf(stderr, "Can not create pidfile!\n");
  54                 exit(1);
  55         }
  56 }
  57
  58 /* How should editor hadle tabs in this file? Add editor commands here.
  59  * vim: noexpandtab sw=8 ts=8 sts=8:
  60  */