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