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/* Copyright (C) 1994-2019 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);
}
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