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/* 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, 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>
#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
}
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