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Diffstat (limited to 'lib/util/locking.c')
| -rw-r--r-- | lib/util/locking.c | 143 |
1 files changed, 143 insertions, 0 deletions
diff --git a/lib/util/locking.c b/lib/util/locking.c new file mode 100644 index 0000000..638b082 --- /dev/null +++ b/lib/util/locking.c @@ -0,0 +1,143 @@ +/* + * SPDX-License-Identifier: ISC + * + * Copyright (c) 1999-2005, 2007, 2009-2015 + * Todd C. Miller <Todd.Miller@sudo.ws> + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + * + * Sponsored in part by the Defense Advanced Research Projects + * Agency (DARPA) and Air Force Research Laboratory, Air Force + * Materiel Command, USAF, under agreement number F39502-99-1-0512. + */ + +/* + * This is an open source non-commercial project. Dear PVS-Studio, please check it. + * PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com + */ + +#include <config.h> + +#include <stdlib.h> +#include <string.h> +#ifdef HAVE_STDBOOL_H +# include <stdbool.h> +#else +# include "compat/stdbool.h" +#endif +#include <errno.h> +#include <fcntl.h> +#include <unistd.h> + +#include "sudo_compat.h" +#include "sudo_util.h" +#include "sudo_debug.h" + +bool +sudo_lock_file_v1(int fd, int type) +{ + return sudo_lock_region_v1(fd, type, 0); +} + +/* + * Lock/unlock all or part of a file. + */ +#ifdef HAVE_LOCKF +bool +sudo_lock_region_v1(int fd, int type, off_t len) +{ + int op, rc; + off_t oldpos = -1; + debug_decl(sudo_lock_region, SUDO_DEBUG_UTIL); + + switch (type) { + case SUDO_LOCK: + sudo_debug_printf(SUDO_DEBUG_INFO, "%s: lock %d:%lld", + __func__, fd, (long long)len); + op = F_LOCK; + break; + case SUDO_TLOCK: + sudo_debug_printf(SUDO_DEBUG_INFO, "%s: tlock %d:%lld", + __func__, fd, (long long)len); + op = F_TLOCK; + break; + case SUDO_UNLOCK: + sudo_debug_printf(SUDO_DEBUG_INFO, "%s: unlock %d:%lld", + __func__, fd, (long long)len); + op = F_ULOCK; + /* Must seek to start of file to unlock the entire thing. */ + if (len == 0 && (oldpos = lseek(fd, 0, SEEK_CUR)) != -1) { + if (lseek(fd, 0, SEEK_SET) == -1) { + sudo_debug_printf( + SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO|SUDO_DEBUG_ERRNO, + "unable to seek to beginning"); + } + } + break; + default: + sudo_debug_printf(SUDO_DEBUG_INFO, "%s: bad lock type %d", + __func__, type); + errno = EINVAL; + debug_return_bool(false); + } + rc = lockf(fd, op, len); + if (oldpos != -1) { + if (lseek(fd, oldpos, SEEK_SET) == -1) { + sudo_debug_printf( + SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO|SUDO_DEBUG_ERRNO, + "unable to restore offset"); + } + } + debug_return_bool(rc == 0); +} +#else +bool +sudo_lock_region_v1(int fd, int type, off_t len) +{ + struct flock lock; + int func; + debug_decl(sudo_lock_file, SUDO_DEBUG_UTIL); + + switch (type) { + case SUDO_LOCK: + sudo_debug_printf(SUDO_DEBUG_INFO, "%s: lock %d:%lld", + __func__, fd, (long long)len); + lock.l_type = F_WRLCK; + func = F_SETLKW; + break; + case SUDO_TLOCK: + sudo_debug_printf(SUDO_DEBUG_INFO, "%s: tlock %d:%lld", + __func__, fd, (long long)len); + lock.l_type = F_WRLCK; + func = F_SETLK; + break; + case SUDO_UNLOCK: + sudo_debug_printf(SUDO_DEBUG_INFO, "%s: unlock %d:%lld", + __func__, fd, (long long)len); + lock.l_type = F_UNLCK; + func = F_SETLK; + break; + default: + sudo_debug_printf(SUDO_DEBUG_INFO, "%s: bad lock type %d", + __func__, type); + errno = EINVAL; + debug_return_bool(false); + } + lock.l_start = 0; + lock.l_len = len; + lock.l_pid = 0; + lock.l_whence = len ? SEEK_CUR : SEEK_SET; + + debug_return_bool(fcntl(fd, func, &lock) == 0); +} +#endif |