mirror of git://git.suckless.org/sbase
94 lines
1.5 KiB
C
94 lines
1.5 KiB
C
/* See LICENSE file for copyright and license details. */
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#include <sys/select.h>
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#include <sys/stat.h>
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#include <sys/time.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include "util.h"
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static void
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usage(void)
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{
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eprintf("usage: respawn [-l fifo] [-d N] cmd [args...]\n");
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}
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int
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main(int argc, char *argv[])
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{
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char *fifo = NULL;
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unsigned int delay = 0;
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pid_t pid;
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char buf[BUFSIZ];
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int savederrno;
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int fd;
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ssize_t n;
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fd_set rdfd;
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ARGBEGIN {
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case 'd':
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delay = estrtol(EARGF(usage()), 0);
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break;
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case 'l':
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fifo = EARGF(usage());
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break;
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default:
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usage();
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} ARGEND;
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if(argc < 1)
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usage();
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if (fifo && delay > 0)
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usage();
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if (fifo) {
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fd = open(fifo, O_RDWR | O_NONBLOCK);
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if (fd < 0)
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eprintf("open %s:", fifo);
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}
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while (1) {
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if (fifo) {
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FD_ZERO(&rdfd);
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FD_SET(fd, &rdfd);
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n = select(fd + 1, &rdfd, NULL, NULL, NULL);
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if (n < 0)
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eprintf("select:");
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if (n == 0 || FD_ISSET(fd, &rdfd) == 0)
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continue;
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while ((n = read(fd, buf, sizeof(buf))) > 0)
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;
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if (n < 0)
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if (errno != EAGAIN)
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eprintf("read %s:", fifo);
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}
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pid = fork();
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if (pid < 0)
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eprintf("fork:");
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switch (pid) {
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case 0:
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if (setsid() < 0)
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eprintf("setsid:");
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execvp(argv[0], argv);
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savederrno = errno;
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weprintf("execvp %s:", argv[0]);
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_exit(savederrno == ENOENT ? 127 : 126);
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break;
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default:
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waitpid(pid, NULL, 0);
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break;
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}
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if (!fifo)
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sleep(delay);
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}
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/* not reachable */
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return EXIT_SUCCESS;
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}
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