61 lines
1.5 KiB
C
61 lines
1.5 KiB
C
/* vi: set sw=4 ts=4: */
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/* pidfile.c
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*
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* Functions to assist in the writing and removing of pidfiles.
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*
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* Russ Dill <Russ.Dill@asu.edu> September 2001
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include "common.h"
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static const char *saved_pidfile;
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static void pidfile_delete(void)
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{
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if (saved_pidfile) unlink(saved_pidfile);
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}
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int pidfile_acquire(const char *pidfile)
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{
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int pid_fd;
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if (!pidfile) return -1;
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pid_fd = open(pidfile, O_CREAT|O_WRONLY|O_TRUNC, 0644);
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if (pid_fd < 0) {
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bb_perror_msg("cannot open pidfile %s", pidfile);
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} else {
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lockf(pid_fd, F_LOCK, 0);
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if (!saved_pidfile)
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atexit(pidfile_delete);
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saved_pidfile = pidfile;
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}
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return pid_fd;
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}
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void pidfile_write_release(int pid_fd)
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{
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if (pid_fd < 0) return;
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fdprintf(pid_fd, "%d\n", getpid());
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lockf(pid_fd, F_UNLCK, 0);
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close(pid_fd);
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}
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