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/* Linux lseek implementation, 32 bits off_t.
Copyright (C) 2016-2020 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
<https://www.gnu.org/licenses/>. */
#include <unistd.h>
#include <stdint.h>
#include <sys/types.h>
#include <sysdep.h>
#include <errno.h>
#ifndef __OFF_T_MATCHES_OFF64_T
/* Test for overflows of structures where we ask the kernel to fill them
in with standard 64-bit syscalls but return them through APIs that
only expose the low 32 bits of some fields. */
static inline off_t lseek_overflow (loff_t res)
{
off_t retval = (off_t) res;
if (retval == res)
return retval;
__set_errno (EOVERFLOW);
return (off_t) -1;
}
off_t
__lseek (int fd, off_t offset, int whence)
{
# ifdef __NR__llseek
loff_t res;
int rc = INLINE_SYSCALL_CALL (_llseek, fd,
(long) (((uint64_t) (offset)) >> 32),
(long) offset, &res, whence);
return rc ?: lseek_overflow (res);
# else
return INLINE_SYSCALL_CALL (lseek, fd, offset, whence);
# endif
}
libc_hidden_def (__lseek)
weak_alias (__lseek, lseek)
strong_alias (__lseek, __libc_lseek)
#endif /* __OFF_T_MATCHES_OFF64_T */
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