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58 lines
1.7 KiB
C
58 lines
1.7 KiB
C
/* Linux lseek implementation, 32 bits off_t.
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Copyright (C) 2016-2017 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library. If not, see
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<http://www.gnu.org/licenses/>. */
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#include <unistd.h>
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#include <stdint.h>
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#include <sys/types.h>
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#include <sysdep.h>
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#include <errno.h>
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#ifndef __OFF_T_MATCHES_OFF64_T
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/* Test for overflows of structures where we ask the kernel to fill them
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in with standard 64-bit syscalls but return them through APIs that
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only expose the low 32 bits of some fields. */
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static inline off_t lseek_overflow (loff_t res)
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{
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off_t retval = (off_t) res;
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if (retval == res)
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return retval;
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__set_errno (EOVERFLOW);
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return (off_t) -1;
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}
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off_t
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__lseek (int fd, off_t offset, int whence)
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{
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# ifdef __NR__llseek
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loff_t res;
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int rc = INLINE_SYSCALL_CALL (_llseek, fd,
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(long) (((uint64_t) (offset)) >> 32),
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(long) offset, &res, whence);
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return rc ?: lseek_overflow (res);
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# else
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return INLINE_SYSCALL_CALL (lseek, fd, offset, whence);
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# endif
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}
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libc_hidden_def (__lseek)
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weak_alias (__lseek, lseek)
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strong_alias (__lseek, __libc_lseek)
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#endif /* __OFF_T_MATCHES_OFF64_T */
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