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fde4439701
file descriptor via exec(3). Now that daemon(8) has been fixed to resolve the issue noted by trociny, the consensus is that this change should be OK.
274 lines
5.7 KiB
C
274 lines
5.7 KiB
C
/*-
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* Copyright (c) 2005 Pawel Jakub Dawidek <pjd@FreeBSD.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/file.h>
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#include <sys/stat.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 <fcntl.h>
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#include <string.h>
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#include <time.h>
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#include <err.h>
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#include <errno.h>
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#include <libutil.h>
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struct pidfh {
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int pf_fd;
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char pf_path[MAXPATHLEN + 1];
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dev_t pf_dev;
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ino_t pf_ino;
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};
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static int _pidfile_remove(struct pidfh *pfh, int freeit);
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static int
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pidfile_verify(const struct pidfh *pfh)
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{
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struct stat sb;
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if (pfh == NULL || pfh->pf_fd == -1)
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return (EDOOFUS);
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/*
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* Check remembered descriptor.
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*/
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if (fstat(pfh->pf_fd, &sb) == -1)
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return (errno);
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if (sb.st_dev != pfh->pf_dev || sb.st_ino != pfh->pf_ino)
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return (EDOOFUS);
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return (0);
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}
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static int
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pidfile_read(const char *path, pid_t *pidptr)
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{
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char buf[16], *endptr;
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int error, fd, i;
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fd = open(path, O_RDONLY);
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if (fd == -1)
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return (errno);
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i = read(fd, buf, sizeof(buf) - 1);
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error = errno; /* Remember errno in case close() wants to change it. */
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close(fd);
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if (i == -1)
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return (error);
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else if (i == 0)
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return (EAGAIN);
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buf[i] = '\0';
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*pidptr = strtol(buf, &endptr, 10);
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if (endptr != &buf[i])
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return (EINVAL);
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return (0);
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}
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struct pidfh *
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pidfile_open(const char *path, mode_t mode, pid_t *pidptr)
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{
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struct pidfh *pfh;
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struct stat sb;
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int error, fd, len, count;
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struct timespec rqtp;
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pfh = malloc(sizeof(*pfh));
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if (pfh == NULL)
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return (NULL);
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if (path == NULL)
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len = snprintf(pfh->pf_path, sizeof(pfh->pf_path),
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"/var/run/%s.pid", getprogname());
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else
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len = snprintf(pfh->pf_path, sizeof(pfh->pf_path),
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"%s", path);
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if (len >= (int)sizeof(pfh->pf_path)) {
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free(pfh);
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errno = ENAMETOOLONG;
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return (NULL);
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}
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/*
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* Open the PID file and obtain exclusive lock.
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* We truncate PID file here only to remove old PID immediatelly,
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* PID file will be truncated again in pidfile_write(), so
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* pidfile_write() can be called multiple times.
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*/
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fd = flopen(pfh->pf_path,
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O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC | O_NONBLOCK, mode);
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if (fd == -1) {
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if (errno == EWOULDBLOCK && pidptr != NULL) {
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count = 20;
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rqtp.tv_sec = 0;
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rqtp.tv_nsec = 5000000;
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for (;;) {
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errno = pidfile_read(pfh->pf_path, pidptr);
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if (errno != EAGAIN || --count == 0)
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break;
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nanosleep(&rqtp, 0);
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}
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if (errno == EAGAIN)
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*pidptr = -1;
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if (errno == 0 || errno == EAGAIN)
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errno = EEXIST;
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}
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free(pfh);
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return (NULL);
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}
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/*
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* Remember file information, so in pidfile_write() we are sure we write
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* to the proper descriptor.
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*/
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if (fstat(fd, &sb) == -1) {
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error = errno;
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unlink(pfh->pf_path);
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close(fd);
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free(pfh);
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errno = error;
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return (NULL);
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}
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pfh->pf_fd = fd;
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pfh->pf_dev = sb.st_dev;
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pfh->pf_ino = sb.st_ino;
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return (pfh);
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}
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int
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pidfile_write(struct pidfh *pfh)
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{
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char pidstr[16];
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int error, fd;
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/*
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* Check remembered descriptor, so we don't overwrite some other
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* file if pidfile was closed and descriptor reused.
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*/
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errno = pidfile_verify(pfh);
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if (errno != 0) {
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/*
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* Don't close descriptor, because we are not sure if it's ours.
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*/
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return (-1);
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}
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fd = pfh->pf_fd;
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/*
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* Truncate PID file, so multiple calls of pidfile_write() are allowed.
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*/
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if (ftruncate(fd, 0) == -1) {
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error = errno;
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_pidfile_remove(pfh, 0);
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errno = error;
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return (-1);
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}
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snprintf(pidstr, sizeof(pidstr), "%u", getpid());
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if (pwrite(fd, pidstr, strlen(pidstr), 0) != (ssize_t)strlen(pidstr)) {
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error = errno;
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_pidfile_remove(pfh, 0);
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errno = error;
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return (-1);
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}
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return (0);
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}
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int
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pidfile_close(struct pidfh *pfh)
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{
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int error;
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error = pidfile_verify(pfh);
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if (error != 0) {
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errno = error;
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return (-1);
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}
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if (close(pfh->pf_fd) == -1)
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error = errno;
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free(pfh);
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if (error != 0) {
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errno = error;
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return (-1);
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}
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return (0);
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}
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static int
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_pidfile_remove(struct pidfh *pfh, int freeit)
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{
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int error;
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error = pidfile_verify(pfh);
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if (error != 0) {
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errno = error;
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return (-1);
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}
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if (unlink(pfh->pf_path) == -1)
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error = errno;
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if (close(pfh->pf_fd) == -1) {
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if (error == 0)
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error = errno;
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}
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if (freeit)
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free(pfh);
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else
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pfh->pf_fd = -1;
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if (error != 0) {
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errno = error;
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return (-1);
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}
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return (0);
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}
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int
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pidfile_remove(struct pidfh *pfh)
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{
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return (_pidfile_remove(pfh, 1));
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}
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int
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pidfile_fileno(const struct pidfh *pfh)
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{
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if (pfh == NULL || pfh->pf_fd == -1) {
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errno = EDOOFUS;
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return (-1);
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}
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return (pfh->pf_fd);
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}
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