| /* Copyright (C) 1994,1996,1997,1998,1999,2000,2003,2006 |
| 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, write to the Free |
| Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 02111-1307 USA. */ |
| |
| #include <sys/types.h> |
| #include <unistd.h> |
| #include <fcntl.h> |
| #include <errno.h> |
| #include <string.h> |
| #include <sysdep.h> |
| |
| #include <kernel-features.h> |
| |
| /* lockf is a simplified interface to fcntl's locking facilities. */ |
| |
| #ifdef __NR_fcntl64 |
| # if __ASSUME_FCNTL64 == 0 |
| /* This variable is shared with all files that check for fcntl64. The |
| declaration is in fcntl.c. */ |
| extern int __have_no_fcntl64; |
| # endif |
| #endif |
| |
| int |
| lockf64 (int fd, int cmd, off64_t len64) |
| { |
| #if __ASSUME_FCNTL64 == 0 |
| struct flock fl; |
| off_t len = (off_t) len64; |
| #endif |
| #ifdef __NR_fcntl64 |
| struct flock64 fl64; |
| int cmd64; |
| #endif |
| |
| #if __ASSUME_FCNTL64 == 0 |
| memset ((char *) &fl, '\0', sizeof (fl)); |
| |
| /* lockf is always relative to the current file position. */ |
| fl.l_whence = SEEK_CUR; |
| fl.l_start = 0; |
| fl.l_len = len; |
| #endif |
| #ifdef __NR_fcntl64 |
| # if __ASSUME_FCNTL64 == 0 |
| if (!__have_no_fcntl64) |
| { |
| # endif |
| memset ((char *) &fl64, '\0', sizeof (fl64)); |
| fl64.l_whence = SEEK_CUR; |
| fl64.l_start = 0; |
| fl64.l_len = len64; |
| # if __ASSUME_FCNTL64 == 0 |
| } |
| # endif |
| #endif |
| |
| #if __ASSUME_FCNTL64 == 0 && !defined __NR_fcntl64 |
| if (len64 != (off64_t) len) |
| { |
| /* We can't represent the length. */ |
| __set_errno (EOVERFLOW); |
| return -1; |
| } |
| #endif |
| 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. */ |
| #if __ASSUME_FCNTL64 > 0 |
| fl64.l_type = F_RDLCK; |
| if (INLINE_SYSCALL (fcntl64, 3, fd, F_GETLK64, &fl64) < 0) |
| return -1; |
| if (fl64.l_type == F_UNLCK || fl64.l_pid == __getpid ()) |
| return 0; |
| __set_errno (EACCES); |
| return -1; |
| #else |
| # ifdef __NR_fcntl64 |
| if (!__have_no_fcntl64) |
| { |
| int res; |
| |
| fl64.l_type = F_RDLCK; |
| res = INLINE_SYSCALL (fcntl64, 3, fd, F_GETLK64, &fl64); |
| /* If errno == ENOSYS try the 32bit interface if len64 can |
| be represented with 32 bits. */ |
| |
| if (res == 0) |
| { |
| if (fl64.l_type == F_UNLCK || fl64.l_pid == __getpid ()) |
| return 0; |
| __set_errno (EACCES); |
| return -1; |
| } |
| else if (errno == ENOSYS) |
| __have_no_fcntl64 = 1; |
| else |
| /* res < 0 && errno != ENOSYS. */ |
| return -1; |
| if (len64 != (off64_t) len) |
| { |
| /* We can't represent the length. */ |
| __set_errno (EOVERFLOW); |
| return -1; |
| } |
| } |
| # endif |
| fl.l_type = F_RDLCK; |
| if (__fcntl (fd, F_GETLK, &fl) < 0) |
| return -1; |
| if (fl.l_type == F_UNLCK || fl.l_pid == __getpid ()) |
| return 0; |
| __set_errno (EACCES); |
| return -1; |
| #endif |
| case F_ULOCK: |
| #if __ASSUME_FCNTL64 == 0 |
| fl.l_type = F_UNLCK; |
| cmd = F_SETLK; |
| #endif |
| #ifdef __NR_fcntl64 |
| fl64.l_type = F_UNLCK; |
| cmd64 = F_SETLK64; |
| #endif |
| break; |
| case F_LOCK: |
| #if __ASSUME_FCNTL64 == 0 |
| fl.l_type = F_WRLCK; |
| cmd = F_SETLKW; |
| #endif |
| #ifdef __NR_fcntl64 |
| fl64.l_type = F_WRLCK; |
| cmd64 = F_SETLKW64; |
| #endif |
| break; |
| case F_TLOCK: |
| #if __ASSUME_FCNTL64 == 0 |
| fl.l_type = F_WRLCK; |
| cmd = F_SETLK; |
| #endif |
| #ifdef __NR_fcntl64 |
| fl64.l_type = F_WRLCK; |
| cmd64 = F_SETLK64; |
| #endif |
| break; |
| |
| default: |
| __set_errno (EINVAL); |
| return -1; |
| } |
| #if __ASSUME_FCNTL64 > 0 |
| return INLINE_SYSCALL (fcntl64, 3, fd, cmd64, &fl64); |
| #else |
| # ifdef __NR_fcntl64 |
| |
| if (!__have_no_fcntl64) |
| { |
| int res = INLINE_SYSCALL (fcntl64, 3, fd, cmd64, &fl64); |
| |
| /* If errno == ENOSYS try the 32bit interface if len64 can |
| be represented with 32 bits. */ |
| if (res == 0 || errno != ENOSYS) |
| return res; |
| |
| __have_no_fcntl64 = 1; |
| |
| if (len64 != (off64_t) len) |
| { |
| /* We can't represent the length. */ |
| __set_errno (EOVERFLOW); |
| return -1; |
| } |
| } |
| # endif |
| return __fcntl (fd, cmd, &fl); |
| #endif |
| } |