appimage/ctdlvisor.c

   1 //
   2 // This is a supervisor program that handles start/stop/restart of
   3 // the various Citadel System components, when we are running on
   4 // an AppImage instance.
   5 //
   6 // Copyright (c) 2021 by the citadel.org team
   7 //
   8 // This program is open source software.  It runs great on the
   9 // Linux operating system (and probably elsewhere).  You can use,
  10 // copy, and run it under the terms of the GNU General Public
  11 // License version 3.  Richard Stallman is an asshole communist.
  12 //
  13 // This program is distributed in the hope that it will be useful,
  14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 // GNU General Public License for more details.
  17
  18
  19 #include <stdlib.h>
  20 #include <unistd.h>
  21 #include <stdio.h>
  22 #include <sys/wait.h>
  23 #include <errno.h>
  24 #include <signal.h>
  25 #include <string.h>
  26 #include <limits.h>
  27
  28 void main_loop(void);
  29 void run_in_foreground(void);
  30
  31 char *data_directory = "/usr/local/citadel";
  32 char *http_port = "80";
  33 char *https_port = "443";
  34 pid_t citserver_pid;
  35 pid_t webcit_pid;
  36 pid_t webcits_pid;
  37 int shutting_down = 0;
  38
  39
  40 void ctdlvisor_exit(int code) {
  41         printf("ctdlvisor: exit code %d\n", code);
  42         exit(code);
  43 }
  44
  45
  46 void signal_handler(int signal) {
  47         fprintf(stderr, "ctdlvisor: caught signal %d\n", signal);
  48
  49         while(shutting_down) {
  50                 fprintf(stderr, "ctdlvisor: already shutting down\n");
  51                 sleep(1);
  52         }
  53
  54         int status;
  55         pid_t who_exited;
  56         char *what_exited = NULL;
  57
  58         shutting_down = 1;
  59         kill(citserver_pid, SIGTERM);
  60         kill(webcit_pid, SIGTERM);
  61         kill(webcits_pid, SIGTERM);
  62         do {
  63                 fprintf(stderr, "ctdlvisor: waiting for all child process to exit...\n");
  64                 who_exited = waitpid(-1, &status, 0);
  65                 if (who_exited == citserver_pid) {
  66                         what_exited = "Citadel Server";
  67                 }
  68                 else if (who_exited == webcit_pid) {
  69                         what_exited = "WebCit HTTP";
  70                 }
  71                 else if (who_exited == webcits_pid) {
  72                         what_exited = "WebCit HTTPS";
  73                 }
  74                 else {
  75                         what_exited = "unknown";
  76                 }
  77                 fprintf(stderr, "ctdlvisor: pid=%d (%s) exited, status=%d, exitcode=%d\n", who_exited, what_exited, status, WEXITSTATUS(status));
  78         } while (who_exited >= 0);
  79
  80         ctdlvisor_exit(0);
  81 }
  82
  83
  84
  85 void detach_from_tty(void) {
  86         signal(SIGHUP, SIG_IGN);
  87         signal(SIGINT, SIG_IGN);
  88         signal(SIGQUIT, SIG_IGN);
  89
  90         setsid();
  91         umask(0);
  92         if (    (freopen("/dev/null", "r", stdin) != stdin) ||
  93                 (freopen("/dev/null", "w", stdout) != stdout) ||
  94                 (freopen("/dev/null", "w", stderr) != stderr)
  95         ) {
  96                 fprintf(stderr, "sysdep: unable to reopen stdio: %s\n", strerror(errno));
  97         }
  98 }
  99
 100
 101 pid_t start_citadel() {
 102         char bin[1024];
 103         sprintf(bin, "%s/usr/local/citadel/citserver", getenv("APPDIR"));
 104         pid_t pid = fork();
 105         if (pid == 0) {
 106                 fprintf(stderr, "ctdlvisor: executing %s\n", bin);
 107                 detach_from_tty();
 108                 execlp(bin, "citserver", "-x9", "-h", data_directory, NULL);
 109                 exit(errno);
 110         }
 111         else {
 112                 return(pid);
 113         }
 114 }
 115
 116
 117 pid_t start_webcit() {
 118         char bin[1024];
 119         sprintf(bin, "%s/usr/local/webcit/webcit", getenv("APPDIR"));
 120         char wchome[1024];
 121         sprintf(wchome, "-h%s/usr/local/webcit", getenv("APPDIR"));
 122         pid_t pid = fork();
 123         if (pid == 0) {
 124                 fprintf(stderr, "ctdlvisor: executing %s\n", bin);
 125                 detach_from_tty();
 126                 execlp(bin, "webcit", "-x9", wchome, "-p", http_port, "uds", data_directory, NULL);
 127                 exit(errno);
 128         }
 129         else {
 130                 return(pid);
 131         }
 132 }
 133
 134
 135 pid_t start_webcits() {
 136         char bin[1024];
 137         sprintf(bin, "%s/usr/local/webcit/webcit", getenv("APPDIR"));
 138         char wchome[1024];
 139         sprintf(wchome, "-h%s/usr/local/webcit", getenv("APPDIR"));
 140         pid_t pid = fork();
 141         if (pid == 0) {
 142                 fprintf(stderr, "ctdlvisor: executing %s\n", bin);
 143                 detach_from_tty();
 144                 execlp(bin, "webcit", "-x9", wchome, "-s", "-p", https_port, "uds", data_directory, NULL);
 145                 exit(errno);
 146         }
 147         else {
 148                 return(pid);
 149         }
 150 }
 151
 152
 153 static char *usage =
 154         "ctdlvisor: usage: ctdlvisor [-h data_directory] [-p http_port] [-s https_port] command\n"
 155         "           'command' must be one of: run, install, start, stop\n"
 156 ;
 157
 158 int main(int argc, char **argv) {
 159         int c;
 160
 161         while ((c = getopt (argc, argv, "h:p:s:")) != -1)  switch(c) {
 162                 case 'h':
 163                         data_directory = optarg;
 164                         break;
 165                 case 'p':
 166                         http_port = optarg;
 167                         break;
 168                 case 's':
 169                         https_port = optarg;
 170                         break;
 171                 default:
 172                         fprintf(stderr, "%s", usage);
 173                         exit(1);
 174         }
 175
 176
 177         if (argc != optind+1) {
 178                 fprintf(stderr, "%s", usage);
 179                 exit(1);
 180         }
 181
 182         if (!strcasecmp(argv[optind], "run")) {
 183                 run_in_foreground();
 184         }
 185         else {
 186                 fprintf(stderr, "%s", usage);
 187                 exit(1);
 188         }
 189
 190         exit(0);
 191 }
 192
 193
 194 void run_in_foreground(void) {
 195         fprintf(stderr, "ctdlvisor: Welcome to the Citadel System, brought to you using AppImage.\n");
 196         fprintf(stderr, "ctdlvisor: LD_LIBRARY_PATH = %s\n", getenv("LD_LIBRARY_PATH"));
 197         fprintf(stderr, "ctdlvisor:            PATH = %s\n", getenv("PATH"));
 198         fprintf(stderr, "ctdlvisor:          APPDIR = %s\n", getenv("APPDIR"));
 199         fprintf(stderr, "ctdlvisor:  data directory = %s\n", data_directory);
 200         fprintf(stderr, "ctdlvisor:       HTTP port = %s\n", http_port);
 201         fprintf(stderr, "ctdlvisor:      HTTPS port = %s\n", https_port);
 202
 203         if (access(data_directory, R_OK|W_OK|X_OK)) {
 204                 fprintf(stderr, "ctdlvisor: %s: %s\n", data_directory, strerror(errno));
 205                 exit(errno);
 206         }
 207
 208         signal(SIGTERM, signal_handler);
 209         signal(SIGHUP, signal_handler);
 210         signal(SIGINT, signal_handler);
 211         signal(SIGQUIT, signal_handler);
 212
 213         citserver_pid = start_citadel();
 214         webcit_pid = start_webcit();
 215         webcits_pid = start_webcits();
 216
 217         main_loop();
 218         exit(0);
 219 }
 220
 221
 222 void main_loop(void) {
 223         int status;
 224         pid_t who_exited;
 225         int citserver_exit_code = 0;
 226
 227         do {
 228                 fprintf(stderr, "ctdlvisor: waiting for any child process to exit...\n");
 229                 who_exited = waitpid(-1, &status, 0);
 230                 fprintf(stderr, "ctdlvisor: pid=%d exited, status=%d, exitcode=%d\n", who_exited, status, WEXITSTATUS(status));
 231
 232                 // A *deliberate* exit of citserver will cause ctdlvisor to shut the whole AppImage down.
 233                 // If it crashes, however, we will start it back up.
 234                 if (who_exited == citserver_pid) {
 235                         citserver_exit_code = WEXITSTATUS(status);
 236                         if (citserver_exit_code == 0) {
 237                                 fprintf(stderr, "ctdlvisor: citserver exited normally - ending AppImage session\n");
 238                                 shutting_down = 1;
 239                                 kill(webcit_pid, SIGTERM);
 240                                 kill(webcits_pid, SIGTERM);
 241                         }
 242                         else if ((citserver_exit_code >= 101) && (citserver_exit_code <= 109)) {
 243                                 fprintf(stderr, "ctdlvisor: citserver exited intentionally - ending AppImage session\n");
 244                                 shutting_down = 1;
 245                                 kill(webcit_pid, SIGTERM);
 246                                 kill(webcits_pid, SIGTERM);
 247                         }
 248                         else {
 249                                 citserver_pid = start_citadel();
 250                         }
 251                 }
 252
 253                 // WebCit processes are restarted if they exit for any reason.
 254                 if ((who_exited == webcit_pid) && (!shutting_down))     webcit_pid = start_webcit();
 255                 if ((who_exited == webcits_pid) && (!shutting_down))    webcits_pid = start_webcits();
 256
 257                 // If we somehow end up in an endless loop, at least slow it down.
 258                 sleep(1);
 259
 260         } while (who_exited >= 0);
 261
 262         ctdlvisor_exit(citserver_exit_code);
 263 }