| /* Copyright (C) 1994-2018 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 of the License, or (at your option) any later version. |
| |
| The GNU C Library is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library; if not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include <sys/types.h> |
| #include <unistd.h> |
| #include <fcntl.h> |
| #include <errno.h> |
| #include <string.h> |
| #include <sysdep.h> |
| |
| /* lockf is a simplified interface to fcntl's locking facilities. */ |
| |
| int |
| lockf64 (int fd, int cmd, off64_t len64) |
| { |
| struct flock64 fl64; |
| int cmd64; |
| int result; |
| |
| memset ((char *) &fl64, '\0', sizeof (fl64)); |
| fl64.l_whence = SEEK_CUR; |
| fl64.l_start = 0; |
| fl64.l_len = len64; |
| |
| switch (cmd) |
| { |
| case F_TEST: |
| /* Test the lock: return 0 if FD is unlocked or locked by this process; |
| return -1, set errno to EACCES, if another process holds the lock. */ |
| fl64.l_type = F_RDLCK; |
| INTERNAL_SYSCALL_DECL (err); |
| result = INTERNAL_SYSCALL (fcntl64, err, 3, fd, F_GETLK64, &fl64); |
| if (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (result, err))) |
| return INLINE_SYSCALL_ERROR_RETURN_VALUE (INTERNAL_SYSCALL_ERRNO (result, |
| err)); |
| if (fl64.l_type == F_UNLCK || fl64.l_pid == __getpid ()) |
| return 0; |
| return INLINE_SYSCALL_ERROR_RETURN_VALUE (EACCES); |
| case F_ULOCK: |
| fl64.l_type = F_UNLCK; |
| cmd64 = F_SETLK64; |
| break; |
| case F_LOCK: |
| fl64.l_type = F_WRLCK; |
| cmd64 = F_SETLKW64; |
| break; |
| case F_TLOCK: |
| fl64.l_type = F_WRLCK; |
| cmd64 = F_SETLK64; |
| break; |
| |
| default: |
| return INLINE_SYSCALL_ERROR_RETURN_VALUE (EINVAL); |
| } |
| return INLINE_SYSCALL (fcntl64, 3, fd, cmd64, &fl64); |
| } |