| | varnish-cache/lib/libvarnish/vpf.c |
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/*- |
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD |
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* |
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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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* Derived from: |
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* $FreeBSD: head/lib/libutil/pidfile.c 184091 2008-10-20 17:41:08Z des $ |
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*/ |
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#include "config.h" |
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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 <fcntl.h> //lint !e537 |
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#include <stdint.h> |
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <string.h> |
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#include <unistd.h> |
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#include "vdef.h" |
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#include "vas.h" // XXX Flexelint "not used" - but req'ed for assert() |
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#include "vfl.h" |
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#include "vpf.h" |
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struct vpf_fh { |
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int pf_fd; |
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char *pf_path; |
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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 |
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149800 |
vpf_verify(const struct vpf_fh *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 (EINVAL); |
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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 (EINVAL); |
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return (0); |
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} |
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int |
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VPF_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 | O_CLOEXEC); |
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if (fd == -1) |
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return (errno); |
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|
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i = read(fd, buf, sizeof(buf) - 1); |
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error = errno; |
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closefd(&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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if (i > 0 && buf[i - 1] == '\n') |
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i--; |
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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 vpf_fh * |
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VPF_Open(const char *path, mode_t mode, pid_t *pidptr) |
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{ |
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struct vpf_fh *pfh; |
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struct stat sb; |
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int fd; |
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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 immediately, |
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* PID file will be truncated again in VPF_Write(), so |
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* VPF_Write() can be called multiple times. |
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*/ |
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fd = VFL_Open(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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errno = VPF_Read(path, pidptr); |
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if (errno == 0) |
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errno = EEXIST; |
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} |
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return (NULL); |
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} |
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/* |
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* Remember file information, so in VPF_Write() we are sure we write |
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* to the proper descriptor. |
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*/ |
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AZ(fstat(fd, &sb)); |
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pfh = malloc(sizeof(*pfh)); |
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AN(pfh); |
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pfh->pf_path = strdup(path); |
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AN(pfh->pf_path); |
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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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void |
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VPF_Write(const struct vpf_fh *pfh) |
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{ |
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char pidstr[16]; |
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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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if (vpf_verify(pfh) != 0) |
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return; |
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/* |
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* Truncate PID file, so multiple calls of VPF_Write() are allowed. |
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*/ |
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AZ(ftruncate(pfh->pf_fd, 0)); |
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bprintf(pidstr, "%jd", (intmax_t)getpid()); |
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assert(pwrite(pfh->pf_fd, pidstr, strlen(pidstr), 0) == |
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(ssize_t)strlen(pidstr)); |
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} |
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void |
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VPF_Remove(struct vpf_fh *pfh) |
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{ |
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if (vpf_verify(pfh) == 0) { |
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(void)unlink(pfh->pf_path); |
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closefd(&pfh->pf_fd); |
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} |
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free(pfh->pf_path); |
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free(pfh); |
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} |