Dmitry V. Levin
5477470e9c
After transition from long to kernel_ulong_t the implementation could be made a bit simpler. * lseek.c (SYS_FUNC(llseek)): Use direct cast to long long instead of zero_extend_signed_to_ull.
94 lines
3.5 KiB
C
94 lines
3.5 KiB
C
/*
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* Copyright (c) 1991, 1992 Paul Kranenburg <pk@cs.few.eur.nl>
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* Copyright (c) 1993 Branko Lankester <branko@hacktic.nl>
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* Copyright (c) 1993, 1994, 1995, 1996 Rick Sladkey <jrs@world.std.com>
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* Copyright (c) 1996-1999 Wichert Akkerman <wichert@cistron.nl>
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* Copyright (c) 2002-2005 Roland McGrath <roland@redhat.com>
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* Copyright (c) 2009 Andreas Schwab <schwab@redhat.com>
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* Copyright (c) 2012 H.J. Lu <hongjiu.lu@intel.com>
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* Copyright (c) 2013 Denys Vlasenko <vda.linux@googlemail.com>
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* Copyright (c) 2014-2016 Dmitry V. Levin <ldv@altlinux.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "defs.h"
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#include "xlat/whence_codes.h"
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/* Linux kernel has exactly one version of lseek:
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* fs/read_write.c::SYSCALL_DEFINE3(lseek, unsigned, fd, off_t, offset, unsigned, origin)
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* In kernel, off_t is always the same as (kernel's) long
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* (see include/uapi/asm-generic/posix_types.h).
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* Use test/x32_lseek.c to test lseek decoding.
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*/
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SYS_FUNC(lseek)
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{
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printfd(tcp, tcp->u_arg[0]);
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kernel_long_t offset;
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# ifndef current_klongsize
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if (current_klongsize < sizeof(kernel_long_t)) {
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offset = (int) tcp->u_arg[1];
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} else
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# endif /* !current_klongsize */
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{
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offset = tcp->u_arg[1];
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}
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tprintf(", %" PRI_kld ", ", offset);
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printxval(whence_codes, tcp->u_arg[2], "SEEK_???");
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return RVAL_DECODED | RVAL_UDECIMAL;
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}
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/* llseek syscall takes explicitly two ulong arguments hi, lo,
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* rather than one 64-bit argument for which ULONG_LONG works
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* appropriate for the native byte order.
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*
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* See kernel's fs/read_write.c::SYSCALL_DEFINE5(llseek, ...)
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*
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* hi,lo are "unsigned longs" and combined exactly this way in kernel:
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* ((loff_t) hi << 32) | lo
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* Note that for architectures with kernel's long wider than userspace long
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* (such as x32), combining code will use *kernel's*, i.e. *wide* longs
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* for hi and lo.
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*/
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SYS_FUNC(llseek)
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{
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if (entering(tcp)) {
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printfd(tcp, tcp->u_arg[0]);
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tprintf(", %lld, ",
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((long long) tcp->u_arg[1] << 32)
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| ((long long) tcp->u_arg[2]));
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} else {
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printnum_int64(tcp, tcp->u_arg[3], "%" PRIu64);
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tprints(", ");
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printxval(whence_codes, tcp->u_arg[4], "SEEK_???");
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}
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return 0;
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}
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