72 lines
1.1 KiB
C
72 lines
1.1 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <errno.h>
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#include <signal.h>
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int pidfile_create(const char *filename)
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{
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int fd = open(filename, O_CREAT | O_EXCL | O_RDWR, 0644);
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if (fd < 0)
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return -1;
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char buf[8];
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int len = snprintf(buf, sizeof(buf), "%d", getpid());
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write(fd, buf, len);
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close(fd);
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return 0;
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}
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int pidfile_remove(const char *filename)
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{
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return unlink(filename);
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}
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pid_t pidfile_check(const char *filename, int remove_stale)
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{
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int fd = open(filename, O_RDWR);
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if (fd < 0) {
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if (errno == ENOENT) {
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errno = 0;
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return 0;
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}
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return -1;
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}
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char buf[9];
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int len = read(fd, buf, sizeof(buf) -1);
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buf[len] = '\0';
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close(fd);
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char *tmp;
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pid_t pid = strtol(buf, &tmp, 10);
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if (len == 0 || tmp == buf)
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pid = -1;
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/* just return the pid */
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if (!remove_stale)
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return pid;
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/* invalid pid, remove stale file */
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if (pid == -1) {
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pidfile_remove(filename);
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return 0;
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}
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/* check if pid is still running */
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if (kill(pid, 0) == 0 || errno != ESRCH) {
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errno = 0;
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return pid;
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}
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errno = 0;
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pidfile_remove(filename);
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return 0;
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}
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