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
  38
  39 void signal_handler(int signal) {
  40         fprintf(stderr, "ctdlvisor: caught signal %d\n", signal);
  41
  42         int status;
  43         pid_t who_exited;
  44         char *what_exited = NULL;
  45
  46         do {
  47                 fprintf(stderr, "ctdlvisor: waiting for any child process to exit...\n");
  48                 who_exited = waitpid(-1, &status, 0);
  49                 if (who_exited == citserver_pid) {
  50                         what_exited = "Citadel Server";
  51                 }
  52                 else if (who_exited == webcit_pid) {
  53                         what_exited = "WebCit HTTP";
  54                 }
  55                 else if (who_exited == webcits_pid) {
  56                         what_exited = "WebCit HTTPS";
  57                 }
  58                 else {
  59                         what_exited = "unknown";
  60                 }
  61                 fprintf(stderr, "ctdlvisor: pid=%d (%s) exited, status=%d, exitcode=%d\n", who_exited, what_exited, status, WEXITSTATUS(status));
  62         } while (who_exited >= 0);
  63
  64         printf("ctdlvisor: exiting from signal catcher.\n");
  65         exit(0);
  66 }
  67
  68
  69
  70 pid_t start_citadel() {
  71         char bin[1024];
  72         sprintf(bin, "%s/usr/local/citadel/citserver", getenv("APPDIR"));
  73         pid_t pid = fork();
  74         if (pid == 0) {
  75                 fprintf(stderr, "ctdlvisor: executing %s\n", bin);
  76                 close(0); close(1); close(2);
  77                 execlp(bin, "citserver", "-x9", "-h", data_directory, NULL);
  78                 exit(errno);
  79         }
  80         else {
  81                 return(pid);
  82         }
  83 }
  84
  85
  86 pid_t start_webcit() {
  87         char bin[1024];
  88         sprintf(bin, "%s/usr/local/webcit/webcit", getenv("APPDIR"));
  89         char wchome[1024];
  90         sprintf(wchome, "-h%s/usr/local/webcit", getenv("APPDIR"));
  91         pid_t pid = fork();
  92         if (pid == 0) {
  93                 fprintf(stderr, "ctdlvisor: executing %s\n", bin);
  94                 close(0); close(1); close(2);
  95                 execlp(bin, "webcit", "-x9", wchome, "-p", http_port, "uds", data_directory, NULL);
  96                 exit(errno);
  97         }
  98         else {
  99                 return(pid);
 100         }
 101 }
 102
 103
 104 pid_t start_webcits() {
 105         char bin[1024];
 106         sprintf(bin, "%s/usr/local/webcit/webcit", getenv("APPDIR"));
 107         char wchome[1024];
 108         sprintf(wchome, "-h%s/usr/local/webcit", getenv("APPDIR"));
 109         pid_t pid = fork();
 110         if (pid == 0) {
 111                 fprintf(stderr, "ctdlvisor: executing %s\n", bin);
 112                 close(0); close(1); close(2);
 113                 execlp(bin, "webcit", "-x9", wchome, "-s", "-p", https_port, "uds", data_directory, NULL);
 114                 exit(errno);
 115         }
 116         else {
 117                 return(pid);
 118         }
 119 }
 120
 121
 122 static char *usage =
 123         "ctdlvisor: usage: ctdlvisor [-h data_directory] [-p http_port] [-s https_port] command\n"
 124         "           'command' must be one of: run, install, start, stop\n"
 125 ;
 126
 127 int main(int argc, char **argv) {
 128         int c;
 129
 130         while ((c = getopt (argc, argv, "h:p:s:")) != -1)  switch(c) {
 131                 case 'h':
 132                         data_directory = optarg;
 133                         break;
 134                 case 'p':
 135                         http_port = optarg;
 136                         break;
 137                 case 's':
 138                         https_port = optarg;
 139                         break;
 140                 default:
 141                         fprintf(stderr, "%s", usage);
 142                         exit(1);
 143         }
 144
 145
 146         if (argc != optind+1) {
 147                 fprintf(stderr, "%s", usage);
 148                 exit(1);
 149         }
 150
 151         if (!strcasecmp(argv[optind], "run")) {
 152                 run_in_foreground();
 153         }
 154         else {
 155                 fprintf(stderr, "%s", usage);
 156                 exit(1);
 157         }
 158
 159         exit(0);
 160 }
 161
 162
 163 void run_in_foreground(void) {
 164         fprintf(stderr, "ctdlvisor: Welcome to the Citadel System, brought to you using AppImage.\n");
 165         fprintf(stderr, "ctdlvisor: LD_LIBRARY_PATH = %s\n", getenv("LD_LIBRARY_PATH"));
 166         fprintf(stderr, "ctdlvisor:            PATH = %s\n", getenv("PATH"));
 167         fprintf(stderr, "ctdlvisor:          APPDIR = %s\n", getenv("APPDIR"));
 168         fprintf(stderr, "ctdlvisor:  data directory = %s\n", data_directory);
 169         fprintf(stderr, "ctdlvisor:       HTTP port = %s\n", http_port);
 170         fprintf(stderr, "ctdlvisor:      HTTPS port = %s\n", https_port);
 171
 172         if (access(data_directory, R_OK|W_OK|X_OK)) {
 173                 fprintf(stderr, "ctdlvisor: %s: %s\n", data_directory, strerror(errno));
 174                 exit(errno);
 175         }
 176
 177         signal(SIGTERM, signal_handler);
 178         signal(SIGHUP, signal_handler);
 179         signal(SIGINT, signal_handler);
 180         signal(SIGQUIT, signal_handler);
 181
 182         citserver_pid = start_citadel();
 183         webcit_pid = start_webcit();
 184         webcits_pid = start_webcits();
 185
 186         main_loop();
 187 }
 188
 189
 190 void main_loop(void) {
 191         int status;
 192         pid_t who_exited;
 193         int shutting_down = 0;
 194         int citserver_exit_code = 0;
 195
 196         do {
 197                 fprintf(stderr, "ctdlvisor: waiting for any child process to exit...\n");
 198                 who_exited = waitpid(-1, &status, 0);
 199                 fprintf(stderr, "ctdlvisor: pid=%d exited, status=%d, exitcode=%d\n", who_exited, status, WEXITSTATUS(status));
 200
 201                 // A *deliberate* exit of citserver will cause ctdlvisor to shut the whole AppImage down.
 202                 // If it crashes, however, we will start it back up.
 203                 if (who_exited == citserver_pid) {
 204                         citserver_exit_code = WEXITSTATUS(status);
 205                         if (citserver_exit_code == 0) {
 206                                 fprintf(stderr, "ctdlvisor: citserver exited normally - ending AppImage session\n");
 207                                 shutting_down = 1;
 208                                 kill(webcit_pid, SIGTERM);
 209                                 kill(webcits_pid, SIGTERM);
 210                         }
 211                         else if ((citserver_exit_code >= 101) && (citserver_exit_code <= 109)) {
 212                                 fprintf(stderr, "ctdlvisor: citserver exited intentionally - ending AppImage session\n");
 213                                 shutting_down = 1;
 214                                 kill(webcit_pid, SIGTERM);
 215                                 kill(webcits_pid, SIGTERM);
 216                         }
 217                         else {
 218                                 citserver_pid = start_citadel();
 219                         }
 220                 }
 221
 222                 // WebCit processes are restarted if they exit for any reason.
 223                 if ((who_exited == webcit_pid) && (!shutting_down))     webcit_pid = start_webcit();
 224                 if ((who_exited == webcits_pid) && (!shutting_down))    webcits_pid = start_webcits();
 225
 226                 // If we somehow end up in an endless loop, at least slow it down.
 227                 sleep(1);
 228
 229         } while (who_exited >= 0);
 230
 231         printf("ctdlvisor: exit code %d\n", citserver_exit_code);
 232         exit(citserver_exit_code);
 233 }