catsit/daemon.c
2020-08-14 16:00:35 -04:00

128 lines
3.3 KiB
C

/* Copyright (C) 2020 C. McEnroe <june@causal.agency>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <grp.h>
#include <pwd.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sysexits.h>
#include <unistd.h>
#include "daemon.h"
#ifndef RUNDIR
#define RUNDIR "/var/run"
#endif
#ifndef ETCDIR
#define ETCDIR "/usr/local/etc"
#endif
static void parseExits(char *list) {
setClear(&stopExits);
while (*list) {
byte exit = strtoul(list, &list, 10);
if (*list) {
if (*list != ',') errx(EX_USAGE, "invalid exit status %s", list);
list++;
}
setAdd(&stopExits, exit);
}
}
int main(int argc, char *argv[]) {
bool daemonize = true;
setAdd(&stopExits, 127);
setAdd(&stopExits, EX_USAGE);
setAdd(&stopExits, EX_DATAERR);
setAdd(&stopExits, EX_NOINPUT);
setAdd(&stopExits, EX_OSFILE);
setAdd(&stopExits, EX_CANTCREAT);
setAdd(&stopExits, EX_CONFIG);
const char *pidPath = NULL;
const char *configPath = ETCDIR "/spawntab";
const char *fifoPath = RUNDIR "/spawnd.pipe";
const char *user = NULL;
const char *group = NULL;
for (int opt; 0 < (opt = getopt(argc, argv, "C:c:df:g:p:s:t:u:"));) {
switch (opt) {
break; case 'C': serviceDir = optarg;
break; case 'c': fifoPath = optarg;
break; case 'd': daemonize = false;
break; case 'f': configPath = optarg;
break; case 'g': group = optarg;
break; case 'p': pidPath = optarg;
break; case 's': parseExits(optarg);
break; case 't': restartInterval = strtoul(optarg, NULL, 10);
break; case 'u': user = optarg;
break; default: return EX_USAGE;
}
}
// TODO: Read config file.
int error = access(serviceDir, X_OK);
if (error) err(EX_NOINPUT, "%s", serviceDir);
errno = 0;
serviceUser = (user ? getpwnam(user) : getpwuid(getuid()));
if (errno) err(EX_OSFILE, "getpwnam");
if (!serviceUser) errx(EX_USAGE, "no such user %s", user);
errno = 0;
serviceGroup = (group ? getgrnam(group) : getgrgid(serviceUser->pw_gid));
if (errno) err(EX_OSFILE, "getgrnam");
if (!serviceGroup) errx(EX_USAGE, "no such group %s", group);
int pidFile = -1;
if (pidPath) {
pidFile = open(
pidPath, O_WRONLY | O_CREAT | O_EXLOCK | O_CLOEXEC, 0600
);
if (pidFile < 0) err(EX_CANTCREAT, "%s", pidPath);
}
// We can't lock a named pipe, so just warn if it already exists.
error = mkfifo(fifoPath, 0600);
if (error) {
if (errno != EEXIST) err(EX_CANTCREAT, "%s", fifoPath);
warn("%s", fifoPath);
}
int fifo = open(fifoPath, O_RDONLY | O_NONBLOCK | O_CLOEXEC);
if (fifo < 0) err(EX_CANTCREAT, "%s", fifoPath);
// TODO: Daemonize, write pid file.
// TODO: Main loop.
close(fifo);
unlink(fifoPath);
if (pidPath) {
close(pidFile);
unlink(pidPath);
}
}