mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-11 13:50:06 +00:00
194 lines
4.6 KiB
C
194 lines
4.6 KiB
C
/* 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
|
|
}
|