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 #include <sys/types.h>
  28 #include <sys/stat.h>
  29
  30 pid_t citserver_pid;
  31 pid_t webcit_pid;
  32 pid_t webcits_pid;
  33 int shutting_down = 0;
  34
  35 // Call this instead of exit() just for common diagnostics etc.
  36 void ctdlvisor_exit(int code) {
  37         printf("ctdlvisor: exit code %d\n", code);
  38         exit(code);
  39 }
  40
  41
  42 // Interrupting this program with a signal will begin an orderly shutdown.
  43 void signal_handler(int signal) {
  44         fprintf(stderr, "ctdlvisor: caught signal %d\n", signal);
  45
  46         while(shutting_down) {
  47                 fprintf(stderr, "ctdlvisor: already shutting down\n");
  48                 sleep(1);
  49         }
  50
  51         int status;
  52         pid_t who_exited;
  53         char *what_exited = NULL;
  54
  55         shutting_down = 1;
  56         kill(citserver_pid, SIGTERM);
  57         kill(webcit_pid, SIGTERM);
  58         kill(webcits_pid, SIGTERM);
  59         do {
  60                 fprintf(stderr, "ctdlvisor: waiting for all child process to exit...\n");
  61                 who_exited = waitpid(-1, &status, 0);
  62                 if (who_exited == citserver_pid) {
  63                         what_exited = "Citadel Server";
  64                 }
  65                 else if (who_exited == webcit_pid) {
  66                         what_exited = "WebCit HTTP";
  67                 }
  68                 else if (who_exited == webcits_pid) {
  69                         what_exited = "WebCit HTTPS";
  70                 }
  71                 else {
  72                         what_exited = "unknown";
  73                 }
  74                 if (who_exited >= 0) {
  75                         if (WIFEXITED(status)) {
  76                                 fprintf(stderr, "ctdlvisor: %d (%s) exited, exitcode=%d\n", who_exited, what_exited, WEXITSTATUS(status));
  77                         }
  78                         else if (WIFSIGNALED(status)) {
  79                                 fprintf(stderr, "ctdlvisor: %d (%s) crashed, signal=%d\n", who_exited, what_exited, WTERMSIG(status));
  80                         }
  81                         else {
  82                                 fprintf(stderr, "ctdlvisor: %d (%s) ended, status=%d\n", who_exited, what_exited, status);
  83                         }
  84                 }
  85         } while (who_exited >= 0);
  86         ctdlvisor_exit(0);
  87 }
  88
  89
  90 void detach_from_tty(void) {
  91         signal(SIGHUP, SIG_IGN);
  92         signal(SIGINT, SIG_IGN);
  93         signal(SIGQUIT, SIG_IGN);
  94
  95         setsid();       // become our own process group leader
  96         umask(0);
  97         if (    (freopen("/dev/null", "r", stdin) != stdin) ||
  98                 (freopen("/dev/null", "w", stdout) != stdout) ||
  99                 (freopen("/dev/null", "w", stderr) != stderr)
 100         ) {
 101                 fprintf(stderr, "sysdep: unable to reopen stdio: %s\n", strerror(errno));
 102         }
 103 }
 104
 105
 106 pid_t start_citadel() {
 107         char bin[1024];
 108         sprintf(bin, "%s/usr/local/citadel/citserver", getenv("APPDIR"));
 109         pid_t pid = fork();
 110         if (pid == 0) {
 111                 fprintf(stderr, "ctdlvisor: executing %s with data directory %s\n", bin, getenv("CTDL_DIR"));
 112                 detach_from_tty();
 113                 execlp(bin, "citserver", "-x9", "-h", getenv("CTDL_DIR"), NULL);
 114                 exit(errno);
 115         }
 116         else {
 117                 fprintf(stderr, "ctdlvisor: citserver running on pid=%d\n", pid);
 118                 return(pid);
 119         }
 120 }
 121
 122
 123 pid_t start_webcit() {
 124         char bin[1024];
 125         sprintf(bin, "%s/usr/local/webcit/webcit", getenv("APPDIR"));
 126         char wchome[1024];
 127         sprintf(wchome, "-h%s/usr/local/webcit", getenv("APPDIR"));
 128         pid_t pid = fork();
 129         if (pid == 0) {
 130                 fprintf(stderr, "ctdlvisor: executing %s\n", bin);
 131                 detach_from_tty();
 132                 execlp(bin, "webcit", "-x9", wchome, "-p", getenv("HTTP_PORT"), "uds", getenv("CTDL_DIR"), NULL);
 133                 exit(errno);
 134         }
 135         else {
 136                 fprintf(stderr, "ctdlvisor: webcit (HTTP) running on pid=%d\n", pid);
 137                 return(pid);
 138         }
 139 }
 140
 141
 142 pid_t start_webcits() {
 143         char bin[1024];
 144         sprintf(bin, "%s/usr/local/webcit/webcit", getenv("APPDIR"));
 145         char wchome[1024];
 146         sprintf(wchome, "-h%s/usr/local/webcit", getenv("APPDIR"));
 147         pid_t pid = fork();
 148         if (pid == 0) {
 149                 fprintf(stderr, "ctdlvisor: executing %s\n", bin);
 150                 detach_from_tty();
 151                 execlp(bin, "webcit", "-x9", wchome, "-s", "-p", getenv("HTTPS_PORT"), "uds", getenv("CTDL_DIR"), NULL);
 152                 exit(errno);
 153         }
 154         else {
 155                 fprintf(stderr, "ctdlvisor: webcit (HTTPS) running on pid=%d\n", pid);
 156                 return(pid);
 157         }
 158 }
 159
 160
 161 void test_binary_compatibility(void) {
 162         char cmd[1024];
 163         int ret;
 164         fprintf(stderr, "ctdlvisor: testing compatibility...\n");
 165         sprintf(cmd, "%s/usr/local/citadel/citserver -c", getenv("APPDIR"));
 166         ret = system(cmd);
 167         if (ret) {
 168                 fprintf(stderr, "ctdlvisor: this appimage cannot run on your system.\n"
 169                                 "           The reason may be indicated by any error messages appearing above.\n");
 170         }
 171         else {
 172                 fprintf(stderr, "ctdlvisor: this appimage appears to be compatible with your system.\n");
 173         }
 174         exit(ret);
 175 }
 176
 177
 178 void main_loop(void) {
 179         int status;
 180         pid_t who_exited;
 181         int citserver_exit_code = 0;
 182
 183         do {
 184                 who_exited = waitpid(-1, &status, 0);
 185                 fprintf(stderr, "ctdlvisor: pid=%d exited, status=%d, exitcode=%d\n", who_exited, status, WEXITSTATUS(status));
 186
 187                 // A *deliberate* exit of citserver will cause ctdlvisor to shut the whole AppImage down.
 188                 // If it crashes, however, we will start it back up.
 189                 if (who_exited == citserver_pid) {
 190                         citserver_exit_code = WEXITSTATUS(status);
 191                         if (citserver_exit_code == 0) {
 192                                 fprintf(stderr, "ctdlvisor: citserver exited normally - ending AppImage session\n");
 193                                 shutting_down = 1;
 194                                 kill(webcit_pid, SIGTERM);
 195                                 kill(webcits_pid, SIGTERM);
 196                         }
 197                         else if ((citserver_exit_code >= 101) && (citserver_exit_code <= 109)) {
 198                                 fprintf(stderr, "ctdlvisor: citserver exited intentionally - ending AppImage session\n");
 199                                 shutting_down = 1;
 200                                 kill(webcit_pid, SIGTERM);
 201                                 kill(webcits_pid, SIGTERM);
 202                         }
 203                         else {
 204                                 citserver_pid = start_citadel();
 205                         }
 206                 }
 207
 208                 // WebCit processes are restarted if they exit for any reason.
 209                 if ((who_exited == webcit_pid) && (!shutting_down))     webcit_pid = start_webcit();
 210                 if ((who_exited == webcits_pid) && (!shutting_down))    webcits_pid = start_webcits();
 211
 212                 // If we somehow end up in an endless loop, at least slow it down.
 213                 sleep(1);
 214
 215         } while (who_exited >= 0);
 216         ctdlvisor_exit(citserver_exit_code);
 217 }
 218
 219
 220 int main(int argc, char **argv) {
 221
 222         if (getenv("APPDIR") == NULL) {
 223                 fprintf(stderr, "ctdlvisor: APPDIR is not set.  This program must be run from within an AppImage.\n");
 224                 ctdlvisor_exit(1);
 225         }
 226
 227         fprintf(stderr, "ctdlvisor: Welcome to the Citadel System, brought to you using AppImage.\n");
 228         fprintf(stderr, "ctdlvisor: LD_LIBRARY_PATH = %s\n", getenv("LD_LIBRARY_PATH"));
 229         fprintf(stderr, "ctdlvisor:            PATH = %s\n", getenv("PATH"));
 230         fprintf(stderr, "ctdlvisor:          APPDIR = %s\n", getenv("APPDIR"));
 231         fprintf(stderr, "ctdlvisor:  data directory = %s\n", getenv("CTDL_DIR"));
 232         fprintf(stderr, "ctdlvisor:       HTTP port = %s\n", getenv("HTTP_PORT"));
 233         fprintf(stderr, "ctdlvisor:      HTTPS port = %s\n", getenv("HTTPS_PORT"));
 234
 235         if (access(getenv("CTDL_DIR"), R_OK|W_OK|X_OK)) {
 236                 fprintf(stderr, "ctdlvisor: %s: %s\n", getenv("CTDL_DIR"), strerror(errno));
 237                 ctdlvisor_exit(errno);
 238         }
 239
 240         signal(SIGTERM, signal_handler);
 241         signal(SIGHUP, signal_handler);
 242         signal(SIGINT, signal_handler);
 243         signal(SIGQUIT, signal_handler);
 244
 245         citserver_pid = start_citadel();
 246         webcit_pid = start_webcit();
 247         webcits_pid = start_webcits();
 248
 249         main_loop();
 250         ctdlvisor_exit(0);
 251 }