7e5641bc76
Since lockf() uses the files's current offset, we need to seek to the start of the file to unlock the entire file.
151 lines
4.0 KiB
C
151 lines
4.0 KiB
C
/*
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* SPDX-License-Identifier: ISC
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*
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* Copyright (c) 1999-2005, 2007, 2009-2015
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* Todd C. Miller <Todd.Miller@sudo.ws>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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* Sponsored in part by the Defense Advanced Research Projects
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* Agency (DARPA) and Air Force Research Laboratory, Air Force
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* Materiel Command, USAF, under agreement number F39502-99-1-0512.
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*/
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/*
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* This is an open source non-commercial project. Dear PVS-Studio, please check it.
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* PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
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*/
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#include <config.h>
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#include <sys/types.h>
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#include <stdlib.h>
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#ifdef HAVE_STRING_H
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# include <string.h>
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#endif /* HAVE_STRING_H */
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#ifdef HAVE_STRINGS_H
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# include <strings.h>
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#endif /* HAVE_STRING_H */
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#ifdef HAVE_STDBOOL_H
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# include <stdbool.h>
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#else
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# include "compat/stdbool.h"
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#endif
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#include <ctype.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include "sudo_compat.h"
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#include "sudo_util.h"
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#include "sudo_debug.h"
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bool
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sudo_lock_file_v1(int fd, int type)
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{
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return sudo_lock_region_v1(fd, type, 0);
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}
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/*
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* Lock/unlock all or part of a file.
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*/
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#ifdef HAVE_LOCKF
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bool
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sudo_lock_region_v1(int fd, int type, off_t len)
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{
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int op, rc;
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off_t oldpos = -1;
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debug_decl(sudo_lock_region, SUDO_DEBUG_UTIL);
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switch (type) {
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case SUDO_LOCK:
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sudo_debug_printf(SUDO_DEBUG_INFO, "%s: lock %d:%lld",
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__func__, fd, (long long)len);
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op = F_LOCK;
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break;
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case SUDO_TLOCK:
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sudo_debug_printf(SUDO_DEBUG_INFO, "%s: tlock %d:%lld",
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__func__, fd, (long long)len);
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op = F_TLOCK;
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break;
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case SUDO_UNLOCK:
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sudo_debug_printf(SUDO_DEBUG_INFO, "%s: unlock %d:%lld",
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__func__, fd, (long long)len);
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op = F_ULOCK;
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/* Must seek to start of file to unlock the entire thing. */
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if (len == 0 && (oldpos = lseek(fd, 0, SEEK_CUR)) != -1) {
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if (lseek(fd, 0, SEEK_SET) == -1) {
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sudo_debug_printf(
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SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO|SUDO_DEBUG_ERRNO,
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"unable to seek to beginning");
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}
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}
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break;
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default:
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sudo_debug_printf(SUDO_DEBUG_INFO, "%s: bad lock type %d",
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__func__, type);
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errno = EINVAL;
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debug_return_bool(false);
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}
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rc = lockf(fd, op, len);
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if (oldpos != -1) {
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if (lseek(fd, oldpos, SEEK_SET) == -1) {
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sudo_debug_printf(
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SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO|SUDO_DEBUG_ERRNO,
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"unable to restore offset");
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}
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}
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debug_return_bool(rc == 0);
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}
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#else
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bool
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sudo_lock_region_v1(int fd, int type, off_t len)
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{
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struct flock lock;
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int func;
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debug_decl(sudo_lock_file, SUDO_DEBUG_UTIL);
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switch (type) {
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case SUDO_LOCK:
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sudo_debug_printf(SUDO_DEBUG_INFO, "%s: lock %d:%lld",
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__func__, fd, (long long)len);
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lock.l_type = F_WRLCK;
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func = F_SETLKW;
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break;
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case SUDO_TLOCK:
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sudo_debug_printf(SUDO_DEBUG_INFO, "%s: tlock %d:%lld",
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__func__, fd, (long long)len);
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lock.l_type = F_WRLCK;
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func = F_SETLK;
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break;
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case SUDO_UNLOCK:
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sudo_debug_printf(SUDO_DEBUG_INFO, "%s: unlock %d:%lld",
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__func__, fd, (long long)len);
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lock.l_type = F_UNLCK;
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func = F_SETLK;
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break;
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default:
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sudo_debug_printf(SUDO_DEBUG_INFO, "%s: bad lock type %d",
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__func__, type);
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errno = EINVAL;
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debug_return_bool(false);
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}
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lock.l_start = 0;
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lock.l_len = len;
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lock.l_pid = 0;
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lock.l_whence = len ? SEEK_CUR : SEEK_SET;
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debug_return_bool(fcntl(fd, func, &lock) == 0);
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}
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#endif
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