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
  23 static char *progname = NULL;
  24
  25
  26 /* CTDB sends SIGTERM, when process must die */
  27 static void sigterm(int sig)
  28 {
  29         pid_t pid;
  30
  31         /* all the child processes are running in the same process group */
  32         pid = getpgrp();
  33         if (pid == -1) {
  34                 kill(-getpid(), SIGKILL);
  35         } else {
  36                 kill(-pid, SIGKILL);
  37         }
  38         _exit(0);
  39 }
  40
  41 static void set_close_on_exec(int fd)
  42 {
  43         int v;
  44
  45         v = fcntl(fd, F_GETFD, 0);
  46         if (v == -1) {
  47                 return;
  48         }
  49         fcntl(fd, F_SETFD, v | FD_CLOEXEC);
  50 }
  51
  52 static int check_executable(const char *path)
  53 {
  54         struct stat st;
  55
  56         if (stat(path, &st) != 0) {
  57                 fprintf(stderr, "Failed to access '%s' - %s\n",
  58                         path, strerror(errno));
  59                 return errno;
  60         }
  61
  62         if (!(st.st_mode & S_IXUSR)) {
  63                 return ENOEXEC;
  64         }
  65
  66         return 0;
  67 }
  68
  69 static void usage(void)
  70 {
  71         fprintf(stderr, "\n");
  72         fprintf(stderr, "Usage: %s <log-fd> <output-fd> <script_path> <event> [<args>]\n",
  73                 progname);
  74 }
  75
  76 int main(int argc, char *argv[])
  77 {
  78         int log_fd, write_fd;
  79         pid_t pid;
  80         int status, output;
  81
  82         progname = argv[0];
  83
  84         if (argc < 5) {
  85                 usage();
  86                 exit(1);
  87         }
  88
  89         log_fd = atoi(argv[1]);
  90         write_fd = atoi(argv[2]);
  91
  92         set_close_on_exec(write_fd);
  93
  94         close(STDOUT_FILENO);
  95         close(STDERR_FILENO);
  96         dup2(log_fd, STDOUT_FILENO);
  97         dup2(log_fd, STDERR_FILENO);
  98         close(log_fd);
  99
 100         if (setpgid(0, 0) != 0) {
 101                 fprintf(stderr, "Failed to create process group for event script - %s\n",
 102                         strerror(errno));
 103                 exit(1);
 104         }
 105
 106         signal(SIGTERM, sigterm);
 107
 108         pid = fork();
 109         if (pid < 0) {
 110                 fprintf(stderr, "Failed to fork - %s\n", strerror(errno));
 111                 exit(errno);
 112         }
 113
 114         if (pid == 0) {
 115                 int save_errno;
 116
 117                 execv(argv[3], &argv[3]);
 118                 if (errno == EACCES) {
 119                         save_errno = check_executable(argv[3]);
 120                 } else {
 121                         save_errno = errno;
 122                         fprintf(stderr, "Error executing '%s' - %s\n",
 123                                 argv[3], strerror(errno));
 124                 }
 125                 _exit(save_errno);
 126         }
 127
 128         waitpid(pid, &status, 0);
 129         if (WIFEXITED(status)) {
 130                 output = WEXITSTATUS(status);
 131                 if (output == ENOENT || output == ENOEXEC) {
 132                         output = -output;
 133                 }
 134                 write(write_fd, &output, sizeof(output));
 135                 exit(output);
 136         }
 137
 138         exit(1);
 139 }