catsit/catsit-watch.c
2021-02-25 15:49:37 -05:00

95 lines
2.4 KiB
C

/* Copyright (C) 2021 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 <sys/types.h>
#include <err.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/event.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <sysexits.h>
#include <unistd.h>
static void watch(int kq, char *path) {
int fd = open(path, O_RDONLY | O_CLOEXEC);
if (fd < 0) err(EX_NOINPUT, "%s", path);
struct kevent event;
EV_SET(
&event, fd, EVFILT_VNODE, EV_ADD | EV_CLEAR,
NOTE_WRITE | NOTE_DELETE, 0, path
);
int nevents = kevent(kq, &event, 1, NULL, 0, NULL);
if (nevents < 0) err(EX_OSERR, "kevent");
}
static void run(char *argv[]) {
pid_t pid = fork();
if (pid < 0) err(EX_OSERR, "fork");
if (!pid) {
execvp(argv[0], argv);
err(126, "%s", argv[0]);
}
int status;
pid = wait(&status);
if (pid < 0) err(EX_OSERR, "wait");
if (WIFEXITED(status)) {
status = WEXITSTATUS(status);
if (status) exit(status);
} else {
exit(status);
}
}
int main(int argc, char *argv[]) {
int kq = kqueue();
if (kq < 0) err(EX_OSERR, "kqueue");
fcntl(kq, F_SETFD, FD_CLOEXEC);
int init = 0;
for (int opt; 0 < (opt = getopt(argc, argv, "f:i"));) {
switch (opt) {
break; case 'f': watch(kq, optarg);
break; case 'i': init = 1;
break; default: return EX_USAGE;
}
}
argc -= optind;
argv += optind;
if (!argc) errx(EX_USAGE, "command required");
#ifdef __OpenBSD__
int error = pledge("stdio proc exec", NULL);
if (error) err(EX_OSERR, "pledge");
#endif
if (init) run(argv);
for (;;) {
struct kevent event;
int nevents = kevent(kq, NULL, 0, &event, 1, NULL);
if (nevents < 0) err(EX_OSERR, "kevent");
if (event.fflags & NOTE_DELETE) {
errx(EX_TEMPFAIL, "%s: file removed", (char *)event.udata);
}
run(argv);
}
}