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                         fprintf(stderr, "ctdlvisor: %d (%s) ended, status=%d\n", who_exited, what_exited, status);
  75                 }
  76         } while (who_exited >= 0);
  77         ctdlvisor_exit(0);
  78 }
  79
  80
  81 void detach_from_tty(void) {
  82         signal(SIGHUP, SIG_IGN);
  83         signal(SIGINT, SIG_IGN);
  84         signal(SIGQUIT, SIG_IGN);
  85
  86         setsid();       // become our own process group leader
  87         umask(0);
  88         if (    (freopen("/dev/null", "r", stdin) != stdin) ||
  89                 (freopen("/dev/null", "w", stdout) != stdout) ||
  90                 (freopen("/dev/null", "w", stderr) != stderr)
  91         ) {
  92                 fprintf(stderr, "sysdep: unable to reopen stdio: %s\n", strerror(errno));
  93         }
  94 }
  95
  96
  97 pid_t start_citadel() {
  98         char bin[1024];
  99         sprintf(bin, "%s/usr/local/citadel/citserver", getenv("APPDIR"));
 100         pid_t pid = fork();
 101         if (pid == 0) {
 102                 fprintf(stderr, "ctdlvisor: executing %s with data directory %s\n", bin, getenv("CTDL_DIR"));
 103                 detach_from_tty();
 104                 execlp(bin, "citserver", "-x9", "-h", getenv("CTDL_DIR"), NULL);
 105                 exit(errno);
 106         }
 107         else {
 108                 fprintf(stderr, "ctdlvisor: citserver running on pid=%d\n", pid);
 109                 return(pid);
 110         }
 111 }
 112
 113
 114 pid_t start_webcit() {
 115         char bin[1024];
 116         sprintf(bin, "%s/usr/local/webcit/webcit", getenv("APPDIR"));
 117         char wchome[1024];
 118         sprintf(wchome, "-h%s/usr/local/webcit", getenv("APPDIR"));
 119         pid_t pid = fork();
 120         if (pid == 0) {
 121                 fprintf(stderr, "ctdlvisor: executing %s\n", bin);
 122                 detach_from_tty();
 123                 execlp(bin, "webcit", "-x9", wchome, "-p", getenv("HTTP_PORT"), "uds", getenv("CTDL_DIR"), NULL);
 124                 exit(errno);
 125         }
 126         else {
 127                 fprintf(stderr, "ctdlvisor: webcit (HTTP) running on pid=%d\n", pid);
 128                 return(pid);
 129         }
 130 }
 131
 132
 133 pid_t start_webcits() {
 134         char bin[1024];
 135         sprintf(bin, "%s/usr/local/webcit/webcit", getenv("APPDIR"));
 136         char wchome[1024];
 137         sprintf(wchome, "-h%s/usr/local/webcit", getenv("APPDIR"));
 138         pid_t pid = fork();
 139         if (pid == 0) {
 140                 fprintf(stderr, "ctdlvisor: executing %s\n", bin);
 141                 detach_from_tty();
 142                 execlp(bin, "webcit", "-x9", wchome, "-s", "-p", getenv("HTTPS_PORT"), "uds", getenv("CTDL_DIR"), NULL);
 143                 exit(errno);
 144         }
 145         else {
 146                 fprintf(stderr, "ctdlvisor: webcit (HTTPS) running on pid=%d\n", pid);
 147                 return(pid);
 148         }
 149 }
 150
 151
 152 void main_loop(void) {
 153         int status;
 154         pid_t who_exited;
 155         int citserver_exit_code = 0;
 156
 157         do {
 158                 who_exited = waitpid(-1, &status, 0);
 159                 fprintf(stderr, "ctdlvisor: pid=%d exited, status=%d, exitcode=%d\n", who_exited, status, WEXITSTATUS(status));
 160
 161                 // A *deliberate* exit of citserver will cause ctdlvisor to shut the whole AppImage down.
 162                 // If it crashes, however, we will start it back up.
 163                 if (who_exited == citserver_pid) {
 164                         citserver_exit_code = WEXITSTATUS(status);
 165                         if ((WIFEXITED(status)) && (citserver_exit_code == 0)) {
 166                                 fprintf(stderr, "ctdlvisor: citserver exited normally - ending AppImage session\n");
 167                                 shutting_down = 1;
 168                                 kill(webcit_pid, SIGTERM);
 169                                 kill(webcits_pid, SIGTERM);
 170                         }
 171                         else if ((WIFEXITED(status)) && (citserver_exit_code >= 101) && (citserver_exit_code <= 109)) {
 172                                 fprintf(stderr, "ctdlvisor: citserver exited intentionally - ending AppImage session\n");
 173                                 shutting_down = 1;
 174                                 kill(webcit_pid, SIGTERM);
 175                                 kill(webcits_pid, SIGTERM);
 176                         }
 177                         else {
 178                                 if (WIFSIGNALED(status)) {
 179                                         fprintf(stderr, "ctdlvisor: citserver crashed on signal %d\n", WTERMSIG(status));
 180                                 }
 181                                 citserver_pid = start_citadel();
 182                         }
 183                 }
 184
 185                 // WebCit processes are restarted if they exit for any reason.
 186                 if ((who_exited == webcit_pid) && (!shutting_down))     webcit_pid = start_webcit();
 187                 if ((who_exited == webcits_pid) && (!shutting_down))    webcits_pid = start_webcits();
 188
 189                 // If we somehow end up in an endless loop, at least slow it down.
 190                 sleep(1);
 191
 192         } while (who_exited >= 0);
 193         ctdlvisor_exit(citserver_exit_code);
 194 }
 195
 196
 197 int main(int argc, char **argv) {
 198         int a;
 199         int migrate_mode = 0;
 200
 201         if (getenv("APPDIR") == NULL) {
 202                 fprintf(stderr, "ctdlvisor: APPDIR is not set.  This program must be run from within an AppImage.\n");
 203                 ctdlvisor_exit(1);
 204         }
 205
 206         /* parse command-line arguments */
 207         while ((a=getopt(argc, argv, "cm")) != EOF) switch(a) {
 208
 209                 // test this binary for compatibility and exit
 210                 case 'c':
 211                         fprintf(stderr, "%s: binary compatibility confirmed\n", argv[0]);
 212                         exit(0);
 213                         break;
 214
 215                 // run ctdlmigrate only
 216                 case 'm':
 217                         migrate_mode = 1;
 218                         break;
 219
 220                 // any other parameter makes it crash and burn
 221                 default:
 222                         fprintf(stderr, "usage\n");
 223                         exit(1);
 224         }
 225
 226         fprintf(stderr, "ctdlvisor: Welcome to the Citadel System, brought to you using AppImage.\n");
 227         fprintf(stderr, "ctdlvisor: LD_LIBRARY_PATH = %s\n", getenv("LD_LIBRARY_PATH"));
 228         fprintf(stderr, "ctdlvisor:            PATH = %s\n", getenv("PATH"));
 229         fprintf(stderr, "ctdlvisor:          APPDIR = %s\n", getenv("APPDIR"));
 230         fprintf(stderr, "ctdlvisor:  data directory = %s\n", getenv("CTDL_DIR"));
 231         fprintf(stderr, "ctdlvisor:       HTTP port = %s\n", getenv("HTTP_PORT"));
 232         fprintf(stderr, "ctdlvisor:      HTTPS port = %s\n", getenv("HTTPS_PORT"));
 233
 234         if (access(getenv("CTDL_DIR"), R_OK|W_OK|X_OK)) {
 235                 fprintf(stderr, "ctdlvisor: %s: %s\n", getenv("CTDL_DIR"), strerror(errno));
 236                 ctdlvisor_exit(errno);
 237         }
 238
 239         signal(SIGHUP, signal_handler);
 240
 241         // "migrate mode" means we just start the server and then run ctdlmigrate interactively.
 242         if (migrate_mode) {
 243                 citserver_pid = start_citadel();
 244                 fprintf(stderr, "ctdlvisor: waiting a moment for citserver to initialize...\n");
 245                 sleep(5);
 246                 char bin[1024];
 247                 sprintf(bin, "%s/usr/local/citadel/ctdlmigrate", getenv("APPDIR"));
 248                 system(bin);
 249                 kill(citserver_pid, SIGTERM);
 250         }
 251
 252         // Otherwise, it's just a normal happy day in Citadel land.
 253         else {
 254                 signal(SIGTERM, signal_handler);
 255                 signal(SIGINT, signal_handler);
 256                 signal(SIGQUIT, signal_handler);
 257
 258                 citserver_pid = start_citadel();
 259                 webcit_pid = start_webcit();
 260                 webcits_pid = start_webcits();
 261
 262                 main_loop();
 263         }
 264
 265         ctdlvisor_exit(0);
 266 }