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
  30 char *data_directory = "/usr/local/citadel";
  31 char *http_port = "80";
  32 char *https_port = "443";
  33 pid_t citserver_pid;
  34 pid_t webcit_pid;
  35 pid_t webcits_pid;
  36
  37
  38 void signal_handler(int signal) {
  39         fprintf(stderr, "ctdlvisor: caught signal %d", signal);
  40
  41         int status;
  42         pid_t who_exited;
  43         char *what_exited = NULL;
  44
  45         do {
  46                 fprintf(stderr, "ctdlvisor: waiting for any child process to exit...\n");
  47                 who_exited = waitpid(-1, &status, 0);
  48                 if (who_exited == citserver_pid) {
  49                         what_exited = "Citadel Server";
  50                 }
  51                 else if (who_exited == webcit_pid) {
  52                         what_exited = "WebCit HTTP";
  53                 }
  54                 else if (who_exited == webcits_pid) {
  55                         what_exited = "WebCit HTTPS";
  56                 }
  57                 else {
  58                         what_exited = "unknown";
  59                 }
  60                 fprintf(stderr, "ctdlvisor: pid=%d (%s) exited, status=%d, exitcode=%d\n", who_exited, what_exited, status, WEXITSTATUS(status));
  61         } while (who_exited >= 0);
  62
  63         printf("ctdlvisor: exiting from signal catcher.\n");
  64         exit(0);
  65 }
  66
  67
  68
  69 pid_t start_citadel() {
  70         char bin[1024];
  71         sprintf(bin, "%s/usr/local/citadel/citserver", getenv("APPDIR"));
  72         pid_t pid = fork();
  73         if (pid == 0) {
  74                 fprintf(stderr, "ctdlvisor: executing %s\n", bin);
  75                 close(0); close(1); close(2);
  76                 execlp(bin, "citserver", "-x9", "-h", data_directory, NULL);
  77                 exit(errno);
  78         }
  79         else {
  80                 return(pid);
  81         }
  82 }
  83
  84
  85 pid_t start_webcit() {
  86         char bin[1024];
  87         sprintf(bin, "%s/usr/local/webcit/webcit", getenv("APPDIR"));
  88         char wchome[1024];
  89         sprintf(wchome, "-h%s/usr/local/webcit", getenv("APPDIR"));
  90         pid_t pid = fork();
  91         if (pid == 0) {
  92                 fprintf(stderr, "ctdlvisor: executing %s\n", bin);
  93                 close(0); close(1); close(2);
  94                 execlp(bin, "webcit", "-x9", wchome, "-p", http_port, "uds", data_directory, NULL);
  95                 exit(errno);
  96         }
  97         else {
  98                 return(pid);
  99         }
 100 }
 101
 102
 103 pid_t start_webcits() {
 104         char bin[1024];
 105         sprintf(bin, "%s/usr/local/webcit/webcit", getenv("APPDIR"));
 106         char wchome[1024];
 107         sprintf(wchome, "-h%s/usr/local/webcit", getenv("APPDIR"));
 108         pid_t pid = fork();
 109         if (pid == 0) {
 110                 fprintf(stderr, "ctdlvisor: executing %s\n", bin);
 111                 close(0); close(1); close(2);
 112                 execlp(bin, "webcit", "-x9", wchome, "-s", "-p", https_port, "uds", data_directory, NULL);
 113                 exit(errno);
 114         }
 115         else {
 116                 return(pid);
 117         }
 118 }
 119
 120
 121 int main(int argc, char **argv) {
 122         int c;
 123
 124         while ((c = getopt (argc, argv, "h:p:s:")) != -1)  switch(c) {
 125                 case 'h':
 126                         data_directory = optarg;
 127                         break;
 128                 case 'p':
 129                         http_port = optarg;
 130                         break;
 131                 case 's':
 132                         https_port = optarg;
 133                         break;
 134                 default:
 135                         fprintf(stderr, "ctdlvisor: usage: ctdlvisor [-h data_directory] [-p http_port] [-s https_port]\n");
 136                         exit(1);
 137         }
 138
 139         fprintf(stderr, "ctdlvisor: Welcome to the Citadel System, brought to you using AppImage.\n");
 140         fprintf(stderr, "ctdlvisor: LD_LIBRARY_PATH = %s\n", getenv("LD_LIBRARY_PATH"));
 141         fprintf(stderr, "ctdlvisor:            PATH = %s\n", getenv("PATH"));
 142         fprintf(stderr, "ctdlvisor:          APPDIR = %s\n", getenv("APPDIR"));
 143         fprintf(stderr, "ctdlvisor:  data directory = %s\n", data_directory);
 144         fprintf(stderr, "ctdlvisor:       HTTP port = %s\n", http_port);
 145         fprintf(stderr, "ctdlvisor:      HTTPS port = %s\n", https_port);
 146
 147         if (access(data_directory, R_OK|W_OK|X_OK)) {
 148                 fprintf(stderr, "ctdlvisor: %s: %s\n", data_directory, strerror(errno));
 149                 exit(errno);
 150         }
 151
 152         signal(SIGTERM, signal_handler);
 153         signal(SIGHUP, signal_handler);
 154         signal(SIGINT, signal_handler);
 155         signal(SIGQUIT, signal_handler);
 156
 157         citserver_pid = start_citadel();
 158         webcit_pid = start_webcit();
 159         webcits_pid = start_webcits();
 160
 161         main_loop();
 162 }
 163
 164
 165 void main_loop(void) {
 166         int status;
 167         pid_t who_exited;
 168         int shutting_down = 0;
 169         int citserver_exit_code = 0;
 170
 171         do {
 172                 fprintf(stderr, "ctdlvisor: waiting for any child process to exit...\n");
 173                 who_exited = waitpid(-1, &status, 0);
 174                 fprintf(stderr, "ctdlvisor: pid=%d exited, status=%d, exitcode=%d\n", who_exited, status, WEXITSTATUS(status));
 175
 176                 // A *deliberate* exit of citserver will cause ctdlvisor to shut the whole AppImage down.
 177                 // If it crashes, however, we will start it back up.
 178                 if (who_exited == citserver_pid) {
 179                         citserver_exit_code = WEXITSTATUS(status);
 180                         if (citserver_exit_code == 0) {
 181                                 fprintf(stderr, "ctdlvisor: citserver exited normally - ending AppImage session\n");
 182                                 shutting_down = 1;
 183                                 kill(webcit_pid, SIGTERM);
 184                                 kill(webcits_pid, SIGTERM);
 185                         }
 186                         else if ((citserver_exit_code >= 101) && (citserver_exit_code <= 109)) {
 187                                 fprintf(stderr, "ctdlvisor: citserver exited intentionally - ending AppImage session\n");
 188                                 shutting_down = 1;
 189                                 kill(webcit_pid, SIGTERM);
 190                                 kill(webcits_pid, SIGTERM);
 191                         }
 192                         else {
 193                                 citserver_pid = start_citadel();
 194                         }
 195                 }
 196
 197                 // WebCit processes are restarted if they exit for any reason.
 198                 if ((who_exited == webcit_pid) && (!shutting_down))     webcit_pid = start_webcit();
 199                 if ((who_exited == webcits_pid) && (!shutting_down))    webcits_pid = start_webcits();
 200
 201                 // If we somehow end up in an endless loop, at least slow it down.
 202                 sleep(1);
 203
 204         } while (who_exited >= 0);
 205
 206         printf("ctdlvisor: exit code %d\n", citserver_exit_code);
 207         exit(citserver_exit_code);
 208 }