ctdb/server/ctdb_event_helper.c

   1 /*
   2    ctdb event script helper
   3
   4    Copyright (C) Amitay Isaacs  2013
   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 "includes.h"
  21 #include "system/filesys.h"
  22 #include "ctdb_private.h"
  23
  24 static char *progname = NULL;
  25
  26
  27 /* CTDB sends SIGTERM, when process must die */
  28 static void sigterm(int sig)
  29 {
  30         pid_t pid;
  31
  32         /* all the child processes are running in the same process group */
  33         pid = getpgrp();
  34         if (pid == -1) {
  35                 kill(-getpid(), SIGKILL);
  36         } else {
  37                 kill(-pid, SIGKILL);
  38         }
  39         _exit(0);
  40 }
  41
  42 static int check_executable(const char *path)
  43 {
  44         struct stat st;
  45
  46         if (stat(path, &st) != 0) {
  47                 fprintf(stderr, "Failed to access '%s' - %s\n",
  48                         path, strerror(errno));
  49                 return errno;
  50         }
  51
  52         if (!(st.st_mode & S_IXUSR)) {
  53                 return ENOEXEC;
  54         }
  55
  56         return 0;
  57 }
  58
  59 static void usage(void)
  60 {
  61         fprintf(stderr, "\n");
  62         fprintf(stderr, "Usage: %s <log-fd> <output-fd> <script_path> <event> [<args>]\n",
  63                 progname);
  64 }
  65
  66 int main(int argc, char *argv[])
  67 {
  68         int log_fd, write_fd;
  69         pid_t pid;
  70         int status, output, ret;
  71
  72         progname = argv[0];
  73
  74         if (argc < 5) {
  75                 usage();
  76                 exit(1);
  77         }
  78
  79         reset_scheduler();
  80
  81         log_fd = atoi(argv[1]);
  82         write_fd = atoi(argv[2]);
  83
  84         set_close_on_exec(write_fd);
  85
  86         close(STDOUT_FILENO);
  87         close(STDERR_FILENO);
  88         dup2(log_fd, STDOUT_FILENO);
  89         dup2(log_fd, STDERR_FILENO);
  90         close(log_fd);
  91
  92         if (setpgid(0, 0) != 0) {
  93                 fprintf(stderr, "Failed to create process group for event script - %s\n",
  94                         strerror(errno));
  95                 exit(1);
  96         }
  97
  98         signal(SIGTERM, sigterm);
  99
 100         pid = fork();
 101         if (pid < 0) {
 102                 int save_errno = errno;
 103                 fprintf(stderr, "Failed to fork - %s\n", strerror(errno));
 104                 sys_write(write_fd, &save_errno, sizeof(save_errno));
 105                 exit(1);
 106         }
 107
 108         if (pid == 0) {
 109                 ret = check_executable(argv[3]);
 110                 if (ret != 0) {
 111                         _exit(ret);
 112                 }
 113                 ret = execv(argv[3], &argv[3]);
 114                 if (ret != 0) {
 115                         int save_errno = errno;
 116                         fprintf(stderr, "Error executing '%s' - %s\n",
 117                                 argv[3], strerror(save_errno));
 118                 }
 119                 /* This should never happen */
 120                 _exit(ENOEXEC);
 121         }
 122
 123         ret = waitpid(pid, &status, 0);
 124         if (ret == -1) {
 125                 output = -errno;
 126                 fprintf(stderr, "waitpid() failed - %s\n", strerror(errno));
 127                 sys_write(write_fd, &output, sizeof(output));
 128                 exit(1);
 129         }
 130         if (WIFEXITED(status)) {
 131                 output = -WEXITSTATUS(status);
 132                 sys_write(write_fd, &output, sizeof(output));
 133                 exit(0);
 134         }
 135         if (WIFSIGNALED(status)) {
 136                 output = -EINTR;
 137                 fprintf(stderr, "Process terminated with signal - %d\n",
 138                         WTERMSIG(status));
 139                 sys_write(write_fd, &output, sizeof(output));
 140                 exit(0);
 141         }
 142
 143         fprintf(stderr, "waitpid() status=%d\n", status);
 144         exit(1);
 145 }