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.  Use, duplication, or disclosure
   8 // is subject to the terms of the GNU General Public License, version 3.
   9 // The program is distributed without any warranty, expressed or implied.
  10
  11 #include <stdlib.h>
  12 #include <unistd.h>
  13 #include <stdio.h>
  14 #include <sys/wait.h>
  15 #include <errno.h>
  16 #include <signal.h>
  17 #include <string.h>
  18 #include <limits.h>
  19 #include <sys/types.h>
  20 #include <sys/stat.h>
  21
  22 pid_t citserver_pid;
  23 pid_t webcit_pid;
  24 pid_t webcits_pid;
  25 int shutting_down = 0;
  26
  27 // Call this instead of exit() just for common diagnostics etc.
  28 void ctdlvisor_exit(int code) {
  29         printf("ctdlvisor: exit code %d\n", code);
  30         exit(code);
  31 }
  32
  33
  34 // Interrupting this program with a signal will begin an orderly shutdown.
  35 void signal_handler(int signal) {
  36         fprintf(stderr, "ctdlvisor: caught signal %d\n", signal);
  37
  38         while(shutting_down) {
  39                 fprintf(stderr, "ctdlvisor: already shutting down\n");
  40                 sleep(1);
  41         }
  42
  43         int status;
  44         pid_t who_exited;
  45         char *what_exited = NULL;
  46
  47         shutting_down = 1;
  48         kill(citserver_pid, SIGTERM);
  49         kill(webcit_pid, SIGTERM);
  50         kill(webcits_pid, SIGTERM);
  51         do {
  52                 fprintf(stderr, "ctdlvisor: waiting for all child process to exit...\n");
  53                 who_exited = waitpid(-1, &status, 0);
  54                 if (who_exited == citserver_pid) {
  55                         what_exited = "Citadel Server";
  56                 }
  57                 else if (who_exited == webcit_pid) {
  58                         what_exited = "WebCit HTTP";
  59                 }
  60                 else if (who_exited == webcits_pid) {
  61                         what_exited = "WebCit HTTPS";
  62                 }
  63                 else {
  64                         what_exited = "unknown";
  65                 }
  66                 if (who_exited >= 0) {
  67                         fprintf(stderr, "ctdlvisor: %d (%s) ended, status=%d\n", who_exited, what_exited, status);
  68                 }
  69         } while (who_exited >= 0);
  70         ctdlvisor_exit(0);
  71 }
  72
  73
  74 void detach_from_tty(void) {
  75         signal(SIGHUP, SIG_IGN);
  76         signal(SIGINT, SIG_IGN);
  77         signal(SIGQUIT, SIG_IGN);
  78
  79         setsid();       // become our own process group leader
  80         umask(0);
  81         if (    (freopen("/dev/null", "r", stdin) != stdin) ||
  82                 (freopen("/dev/null", "w", stdout) != stdout) ||
  83                 (freopen("/dev/null", "w", stderr) != stderr)
  84         ) {
  85                 fprintf(stderr, "sysdep: unable to reopen stdio: %s\n", strerror(errno));
  86         }
  87 }
  88
  89
  90 pid_t start_citadel() {
  91         char bin[1024];
  92         sprintf(bin, "%s/usr/local/citadel/citserver", getenv("APPDIR"));
  93         pid_t pid = fork();
  94         if (pid == 0) {
  95                 fprintf(stderr, "ctdlvisor: executing %s with data directory %s\n", bin, getenv("CTDL_DIR"));
  96                 detach_from_tty();
  97                 execlp(bin, "citserver", "-x9", "-h", getenv("CTDL_DIR"), NULL);
  98                 exit(errno);
  99         }
 100         else {
 101                 fprintf(stderr, "ctdlvisor: citserver running on pid=%d\n", pid);
 102                 return(pid);
 103         }
 104 }
 105
 106
 107 pid_t start_webcit() {
 108         char bin[1024];
 109         sprintf(bin, "%s/usr/local/webcit/webcit", getenv("APPDIR"));
 110         char wchome[1024];
 111         sprintf(wchome, "-h%s/usr/local/webcit", getenv("APPDIR"));
 112         pid_t pid = fork();
 113         if (pid == 0) {
 114                 fprintf(stderr, "ctdlvisor: executing %s\n", bin);
 115                 detach_from_tty();
 116                 execlp(bin, "webcit", "-x9", wchome, "-p", getenv("HTTP_PORT"), "uds", getenv("CTDL_DIR"), NULL);
 117                 exit(errno);
 118         }
 119         else {
 120                 fprintf(stderr, "ctdlvisor: webcit (HTTP) running on pid=%d\n", pid);
 121                 return(pid);
 122         }
 123 }
 124
 125
 126 pid_t start_webcits() {
 127         char bin[1024];
 128         sprintf(bin, "%s/usr/local/webcit/webcit", getenv("APPDIR"));
 129         char wchome[1024];
 130         sprintf(wchome, "-h%s/usr/local/webcit", getenv("APPDIR"));
 131         pid_t pid = fork();
 132         if (pid == 0) {
 133                 fprintf(stderr, "ctdlvisor: executing %s\n", bin);
 134                 detach_from_tty();
 135                 execlp(bin, "webcit", "-x9", wchome, "-s", "-p", getenv("HTTPS_PORT"), "uds", getenv("CTDL_DIR"), NULL);
 136                 exit(errno);
 137         }
 138         else {
 139                 fprintf(stderr, "ctdlvisor: webcit (HTTPS) running on pid=%d\n", pid);
 140                 return(pid);
 141         }
 142 }
 143
 144
 145 void main_loop(void) {
 146         int status;
 147         pid_t who_exited;
 148         int citserver_exit_code = 0;
 149
 150         do {
 151                 who_exited = waitpid(-1, &status, 0);
 152                 fprintf(stderr, "ctdlvisor: pid=%d exited, status=%d, exitcode=%d\n", who_exited, status, WEXITSTATUS(status));
 153
 154                 // A *deliberate* exit of citserver will cause ctdlvisor to shut the whole AppImage down.
 155                 // If it crashes, however, we will start it back up.
 156                 if (who_exited == citserver_pid) {
 157                         citserver_exit_code = WEXITSTATUS(status);
 158                         if ((WIFEXITED(status)) && (citserver_exit_code == 0)) {
 159                                 fprintf(stderr, "ctdlvisor: citserver exited normally - ending AppImage session\n");
 160                                 shutting_down = 1;
 161                                 kill(webcit_pid, SIGTERM);
 162                                 kill(webcits_pid, SIGTERM);
 163                         }
 164                         else if ((WIFEXITED(status)) && (citserver_exit_code >= 101) && (citserver_exit_code <= 109)) {
 165                                 fprintf(stderr, "ctdlvisor: citserver exited intentionally - ending AppImage session\n");
 166                                 shutting_down = 1;
 167                                 kill(webcit_pid, SIGTERM);
 168                                 kill(webcits_pid, SIGTERM);
 169                         }
 170                         else {
 171                                 if (WIFSIGNALED(status)) {
 172                                         fprintf(stderr, "ctdlvisor: citserver crashed on signal %d\n", WTERMSIG(status));
 173                                 }
 174                                 citserver_pid = start_citadel();
 175                         }
 176                 }
 177
 178                 // WebCit processes are restarted if they exit for any reason.
 179                 if ((who_exited == webcit_pid) && (!shutting_down))     webcit_pid = start_webcit();
 180                 if ((who_exited == webcits_pid) && (!shutting_down))    webcits_pid = start_webcits();
 181
 182                 // If we somehow end up in an endless loop, at least slow it down.
 183                 sleep(1);
 184
 185         } while (who_exited >= 0);
 186         ctdlvisor_exit(citserver_exit_code);
 187 }
 188
 189
 190 int main(int argc, char **argv) {
 191         int a;
 192         int migrate_mode = 0;
 193
 194         if (getenv("APPDIR") == NULL) {
 195                 fprintf(stderr, "ctdlvisor: APPDIR is not set.  This program must be run from within an AppImage.\n");
 196                 ctdlvisor_exit(1);
 197         }
 198
 199         /* parse command-line arguments */
 200         while ((a=getopt(argc, argv, "cm")) != EOF) switch(a) {
 201
 202                 // test this binary for compatibility and exit
 203                 case 'c':
 204                         fprintf(stderr, "%s: binary compatibility confirmed\n", argv[0]);
 205                         exit(0);
 206                         break;
 207
 208                 // run ctdlmigrate only
 209                 case 'm':
 210                         migrate_mode = 1;
 211                         break;
 212
 213                 // any other parameter makes it crash and burn
 214                 default:
 215                         fprintf(stderr, "usage\n");
 216                         exit(1);
 217         }
 218
 219         fprintf(stderr, "ctdlvisor: Welcome to the Citadel System, brought to you using AppImage.\n");
 220         fprintf(stderr, "ctdlvisor: LD_LIBRARY_PATH = %s\n", getenv("LD_LIBRARY_PATH"));
 221         fprintf(stderr, "ctdlvisor:            PATH = %s\n", getenv("PATH"));
 222         fprintf(stderr, "ctdlvisor:          APPDIR = %s\n", getenv("APPDIR"));
 223         fprintf(stderr, "ctdlvisor:  data directory = %s\n", getenv("CTDL_DIR"));
 224         fprintf(stderr, "ctdlvisor:       HTTP port = %s\n", getenv("HTTP_PORT"));
 225         fprintf(stderr, "ctdlvisor:      HTTPS port = %s\n", getenv("HTTPS_PORT"));
 226
 227         if (access(getenv("CTDL_DIR"), R_OK|W_OK|X_OK)) {
 228                 fprintf(stderr, "ctdlvisor: %s: %s\n", getenv("CTDL_DIR"), strerror(errno));
 229                 ctdlvisor_exit(errno);
 230         }
 231
 232         signal(SIGHUP, signal_handler);
 233
 234         // "migrate mode" means we just start the server and then run ctdlmigrate interactively.
 235         if (migrate_mode) {
 236                 citserver_pid = start_citadel();
 237                 fprintf(stderr, "ctdlvisor: waiting a moment for citserver to initialize...\n");
 238                 sleep(5);
 239                 char bin[1024];
 240                 sprintf(bin, "%s/usr/local/citadel/ctdlmigrate -h %s", getenv("APPDIR"), getenv("CTDL_DIR"));
 241                 system(bin);
 242                 kill(citserver_pid, SIGTERM);
 243         }
 244
 245         // Otherwise, it's just a normal happy day in Citadel land.
 246         else {
 247                 signal(SIGTERM, signal_handler);
 248                 signal(SIGINT, signal_handler);
 249                 signal(SIGQUIT, signal_handler);
 250
 251                 citserver_pid = start_citadel();
 252                 webcit_pid = start_webcit();
 253                 webcits_pid = start_webcits();
 254
 255                 main_loop();
 256         }
 257
 258         ctdlvisor_exit(0);
 259 }