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/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2005 Pawel Jakub Dawidek <pjd@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* Derived from:
* $FreeBSD: head/lib/libutil/pidfile.c 184091 2008-10-20 17:41:08Z des $
*/
#include "config.h"
#include <sys/param.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <fcntl.h> //lint !e537
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "vdef.h"
#include "vas.h" // XXX Flexelint "not used" - but req'ed for assert()
#include "vfl.h"
#include "vpf.h"
struct vpf_fh {
int pf_fd;
char *pf_path;
dev_t pf_dev;
ino_t pf_ino;
};
static int
vpf_verify(const struct vpf_fh *pfh)
{
struct stat sb;
if (pfh == NULL || pfh->pf_fd == -1)
return (EINVAL);
/*
* Check remembered descriptor.
*/
if (fstat(pfh->pf_fd, &sb) == -1)
return (errno);
if (sb.st_dev != pfh->pf_dev || sb.st_ino != pfh->pf_ino)
return (EINVAL);
return (0);
}
int
VPF_Read(const char *path, pid_t *pidptr)
{
char buf[16], *endptr;
int error, fd, i;
fd = open(path, O_RDONLY | O_CLOEXEC);
if (fd == -1)
return (errno);
i = read(fd, buf, sizeof(buf) - 1);
error = errno;
closefd(&fd);
if (i == -1)
return (error);
else if (i == 0)
return (EAGAIN);
if (i > 0 && buf[i - 1] == '\n')
i--;
buf[i] = '\0';
*pidptr = strtol(buf, &endptr, 10);
if (endptr != &buf[i])
return (EINVAL);
return (0);
}
struct vpf_fh *
VPF_Open(const char *path, mode_t mode, pid_t *pidptr)
{
struct vpf_fh *pfh;
struct stat sb;
int fd;
/*
* Open the PID file and obtain exclusive lock.
* We truncate PID file here only to remove old PID immediately,
* PID file will be truncated again in VPF_Write(), so
* VPF_Write() can be called multiple times.
*/
fd = VFL_Open(path,
O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC | O_NONBLOCK, mode);
if (fd == -1) {
if (errno == EWOULDBLOCK && pidptr != NULL) {
errno = VPF_Read(path, pidptr);
if (errno == 0)
errno = EEXIST;
}
return (NULL);
}
/*
* Remember file information, so in VPF_Write() we are sure we write
* to the proper descriptor.
*/
AZ(fstat(fd, &sb));
pfh = malloc(sizeof(*pfh));
AN(pfh);
pfh->pf_path = strdup(path);
AN(pfh->pf_path);
pfh->pf_fd = fd;
pfh->pf_dev = sb.st_dev;
pfh->pf_ino = sb.st_ino;
return (pfh);
}
void
VPF_Write(const struct vpf_fh *pfh)
{
char pidstr[16];
/*
* Check remembered descriptor, so we don't overwrite some other
* file if pidfile was closed and descriptor reused.
*/
if (vpf_verify(pfh) != 0)
return;
/*
* Truncate PID file, so multiple calls of VPF_Write() are allowed.
*/
AZ(ftruncate(pfh->pf_fd, 0));
bprintf(pidstr, "%jd", (intmax_t)getpid());
assert(pwrite(pfh->pf_fd, pidstr, strlen(pidstr), 0) ==
(ssize_t)strlen(pidstr));
}
void
VPF_Remove(struct vpf_fh *pfh)
{
if (vpf_verify(pfh) == 0) {
(void)unlink(pfh->pf_path);
closefd(&pfh->pf_fd);
}
free(pfh->pf_path);
free(pfh);
}
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