appimage/ctdlvisor.c

   1 // This is a supervisor program that handles start/stop/restart of
   2 // the various Citadel System components, when we are running on
   3 // an AppImage instance.
   4 //
   5 // Copyright (c) 2021 by the citadel.org team
   6 //
   7 // This program is open source software.  It runs great on the
   8 // Linux operating system (and probably elsewhere).  You can use,
   9 // copy, and run it under the terms of the GNU General Public
  10 // License version 3.
  11 //
  12 // This program is distributed in the hope that it will be useful,
  13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 // GNU General Public License for more details.
  16
  17
  18 #include <stdlib.h>
  19 #include <unistd.h>
  20 #include <stdio.h>
  21 #include <sys/wait.h>
  22 #include <errno.h>
  23 #include <signal.h>
  24 #include <string.h>
  25 #include <limits.h>
  26 #include <sys/types.h>
  27 #include <sys/stat.h>
  28
  29 pid_t citserver_pid;
  30 pid_t webcit_pid;
  31 pid_t webcits_pid;
  32 int shutting_down = 0;
  33
  34 // Call this instead of exit() just for common diagnostics etc.
  35 void ctdlvisor_exit(int code) {
  36         printf("ctdlvisor: exit code %d\n", code);
  37         exit(code);
  38 }
  39
  40
  41 // Interrupting this program with a signal will begin an orderly shutdown.
  42 void signal_handler(int signal) {
  43         fprintf(stderr, "ctdlvisor: caught signal %d\n", signal);
  44
  45         while(shutting_down) {
  46                 fprintf(stderr, "ctdlvisor: already shutting down\n");
  47                 sleep(1);
  48         }
  49
  50         int status;
  51         pid_t who_exited;
  52         char *what_exited = NULL;
  53
  54         shutting_down = 1;
  55         kill(citserver_pid, SIGTERM);
  56         kill(webcit_pid, SIGTERM);
  57         kill(webcits_pid, SIGTERM);
  58         do {
  59                 fprintf(stderr, "ctdlvisor: waiting for all child process to exit...\n");
  60                 who_exited = waitpid(-1, &status, 0);
  61                 if (who_exited == citserver_pid) {
  62                         what_exited = "Citadel Server";
  63                 }
  64                 else if (who_exited == webcit_pid) {
  65                         what_exited = "WebCit HTTP";
  66                 }
  67                 else if (who_exited == webcits_pid) {
  68                         what_exited = "WebCit HTTPS";
  69                 }
  70                 else {
  71                         what_exited = "unknown";
  72                 }
  73                 if (who_exited >= 0) {
  74                         if (WIFEXITED(status)) {
  75                                 fprintf(stderr, "ctdlvisor: %d (%s) exited, exitcode=%d\n", who_exited, what_exited, WEXITSTATUS(status));
  76                         }
  77                         else if (WIFSIGNALED(status)) {
  78                                 fprintf(stderr, "ctdlvisor: %d (%s) crashed, signal=%d\n", who_exited, what_exited, WTERMSIG(status));
  79                         }
  80                         else {
  81                                 fprintf(stderr, "ctdlvisor: %d (%s) ended, status=%d\n", who_exited, what_exited, status);
  82                         }
  83                 }
  84         } while (who_exited >= 0);
  85         ctdlvisor_exit(0);
  86 }
  87
  88
  89 void detach_from_tty(void) {
  90         signal(SIGHUP, SIG_IGN);
  91         signal(SIGINT, SIG_IGN);
  92         signal(SIGQUIT, SIG_IGN);
  93
  94         setsid();       // become our own process group leader
  95         umask(0);
  96         if (    (freopen("/dev/null", "r", stdin) != stdin) ||
  97                 (freopen("/dev/null", "w", stdout) != stdout) ||
  98                 (freopen("/dev/null", "w", stderr) != stderr)
  99         ) {
 100                 fprintf(stderr, "sysdep: unable to reopen stdio: %s\n", strerror(errno));
 101         }
 102 }
 103
 104
 105 pid_t start_citadel() {
 106         char bin[1024];
 107         sprintf(bin, "%s/usr/local/citadel/citserver", getenv("APPDIR"));
 108         pid_t pid = fork();
 109         if (pid == 0) {
 110                 fprintf(stderr, "ctdlvisor: executing %s with data directory %s\n", bin, getenv("CTDL_DIR"));
 111                 detach_from_tty();
 112                 execlp(bin, "citserver", "-x9", "-h", getenv("CTDL_DIR"), NULL);
 113                 exit(errno);
 114         }
 115         else {
 116                 fprintf(stderr, "ctdlvisor: citserver running on pid=%d\n", pid);
 117                 return(pid);
 118         }
 119 }
 120
 121
 122 pid_t start_webcit() {
 123         char bin[1024];
 124         sprintf(bin, "%s/usr/local/webcit/webcit", getenv("APPDIR"));
 125         char wchome[1024];
 126         sprintf(wchome, "-h%s/usr/local/webcit", getenv("APPDIR"));
 127         pid_t pid = fork();
 128         if (pid == 0) {
 129                 fprintf(stderr, "ctdlvisor: executing %s\n", bin);
 130                 detach_from_tty();
 131                 execlp(bin, "webcit", "-x9", wchome, "-p", getenv("HTTP_PORT"), "uds", getenv("CTDL_DIR"), NULL);
 132                 exit(errno);
 133         }
 134         else {
 135                 fprintf(stderr, "ctdlvisor: webcit (HTTP) running on pid=%d\n", pid);
 136                 return(pid);
 137         }
 138 }
 139
 140
 141 pid_t start_webcits() {
 142         char bin[1024];
 143         sprintf(bin, "%s/usr/local/webcit/webcit", getenv("APPDIR"));
 144         char wchome[1024];
 145         sprintf(wchome, "-h%s/usr/local/webcit", getenv("APPDIR"));
 146         pid_t pid = fork();
 147         if (pid == 0) {
 148                 fprintf(stderr, "ctdlvisor: executing %s\n", bin);
 149                 detach_from_tty();
 150                 execlp(bin, "webcit", "-x9", wchome, "-s", "-p", getenv("HTTPS_PORT"), "uds", getenv("CTDL_DIR"), NULL);
 151                 exit(errno);
 152         }
 153         else {
 154                 fprintf(stderr, "ctdlvisor: webcit (HTTPS) running on pid=%d\n", pid);
 155                 return(pid);
 156         }
 157 }
 158
 159
 160 void main_loop(void) {
 161         int status;
 162         pid_t who_exited;
 163         int citserver_exit_code = 0;
 164
 165         do {
 166                 who_exited = waitpid(-1, &status, 0);
 167                 fprintf(stderr, "ctdlvisor: pid=%d exited, status=%d, exitcode=%d\n", who_exited, status, WEXITSTATUS(status));
 168
 169                 // A *deliberate* exit of citserver will cause ctdlvisor to shut the whole AppImage down.
 170                 // If it crashes, however, we will start it back up.
 171                 if (who_exited == citserver_pid) {
 172                         citserver_exit_code = WEXITSTATUS(status);
 173                         if (citserver_exit_code == 0) {
 174                                 fprintf(stderr, "ctdlvisor: citserver exited normally - ending AppImage session\n");
 175                                 shutting_down = 1;
 176                                 kill(webcit_pid, SIGTERM);
 177                                 kill(webcits_pid, SIGTERM);
 178                         }
 179                         else if ((citserver_exit_code >= 101) && (citserver_exit_code <= 109)) {
 180                                 fprintf(stderr, "ctdlvisor: citserver exited intentionally - ending AppImage session\n");
 181                                 shutting_down = 1;
 182                                 kill(webcit_pid, SIGTERM);
 183                                 kill(webcits_pid, SIGTERM);
 184                         }
 185                         else {
 186                                 citserver_pid = start_citadel();
 187                         }
 188                 }
 189
 190                 // WebCit processes are restarted if they exit for any reason.
 191                 if ((who_exited == webcit_pid) && (!shutting_down))     webcit_pid = start_webcit();
 192                 if ((who_exited == webcits_pid) && (!shutting_down))    webcits_pid = start_webcits();
 193
 194                 // If we somehow end up in an endless loop, at least slow it down.
 195                 sleep(1);
 196
 197         } while (who_exited >= 0);
 198         ctdlvisor_exit(citserver_exit_code);
 199 }
 200
 201
 202 int main(int argc, char **argv) {
 203
 204         if (getenv("APPDIR") == NULL) {
 205                 fprintf(stderr, "ctdlvisor: APPDIR is not set.  This program must be run from within an AppImage.\n");
 206                 ctdlvisor_exit(1);
 207         }
 208
 209         fprintf(stderr, "ctdlvisor: Welcome to the Citadel System, brought to you using AppImage.\n");
 210         fprintf(stderr, "ctdlvisor: LD_LIBRARY_PATH = %s\n", getenv("LD_LIBRARY_PATH"));
 211         fprintf(stderr, "ctdlvisor:            PATH = %s\n", getenv("PATH"));
 212         fprintf(stderr, "ctdlvisor:          APPDIR = %s\n", getenv("APPDIR"));
 213         fprintf(stderr, "ctdlvisor:  data directory = %s\n", getenv("CTDL_DIR"));
 214         fprintf(stderr, "ctdlvisor:       HTTP port = %s\n", getenv("HTTP_PORT"));
 215         fprintf(stderr, "ctdlvisor:      HTTPS port = %s\n", getenv("HTTPS_PORT"));
 216
 217         if (access(getenv("CTDL_DIR"), R_OK|W_OK|X_OK)) {
 218                 fprintf(stderr, "ctdlvisor: %s: %s\n", getenv("CTDL_DIR"), strerror(errno));
 219                 ctdlvisor_exit(errno);
 220         }
 221
 222         signal(SIGTERM, signal_handler);
 223         signal(SIGHUP, signal_handler);
 224         signal(SIGINT, signal_handler);
 225         signal(SIGQUIT, signal_handler);
 226
 227         citserver_pid = start_citadel();
 228         webcit_pid = start_webcit();
 229         webcits_pid = start_webcits();
 230
 231         main_loop();
 232         ctdlvisor_exit(0);
 233 }