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/*
* Copyright (c) 1991, 1992 Paul Kranenburg <pk@cs.few.eur.nl>
* Copyright (c) 1993 Branko Lankester <branko@hacktic.nl>
* Copyright (c) 1993, 1994, 1995, 1996 Rick Sladkey <jrs@world.std.com>
* Copyright (c) 1996-1999 Wichert Akkerman <wichert@cistron.nl>
* Copyright (c) 2002-2005 Roland McGrath <roland@redhat.com>
* Copyright (c) 2009 Andreas Schwab <schwab@redhat.com>
* Copyright (c) 2012 H.J. Lu <hongjiu.lu@intel.com>
* Copyright (c) 2013 Denys Vlasenko <vda.linux@googlemail.com>
* Copyright (c) 2014-2016 Dmitry V. Levin <ldv@strace.io>
* Copyright (c) 2014-2021 The strace developers.
* All rights reserved.
*
* SPDX-License-Identifier: LGPL-2.1-or-later
*/
#include "defs.h"
#include "xlat/whence_codes.h"
/* Linux kernel has exactly one version of lseek:
* fs/read_write.c::SYSCALL_DEFINE3(lseek, unsigned, fd, off_t, offset, unsigned, origin)
* In kernel, off_t is always the same as (kernel's) long
* (see include/uapi/asm-generic/posix_types.h).
* Use test/x32_lseek.c to test lseek decoding.
*/
SYS_FUNC(lseek)
{
/* fd */
printfd(tcp, tcp->u_arg[0]);
tprint_arg_next();
kernel_long_t offset;
#ifndef current_klongsize
if (current_klongsize < sizeof(kernel_long_t)) {
offset = (int) tcp->u_arg[1];
} else
#endif /* !current_klongsize */
{
offset = tcp->u_arg[1];
}
/* offset */
PRINT_VAL_D(offset);
tprint_arg_next();
/* whence */
printxval(whence_codes, tcp->u_arg[2], "SEEK_???");
return RVAL_DECODED;
}
/* llseek syscall takes explicitly two ulong arguments hi, lo,
* rather than one 64-bit argument for which ULONG_LONG works
* appropriate for the native byte order.
*
* See kernel's fs/read_write.c::SYSCALL_DEFINE5(llseek, ...)
*
* hi,lo are "unsigned longs" and combined exactly this way in kernel:
* ((loff_t) hi << 32) | lo
* Note that for architectures with kernel's long wider than userspace long
* (such as x32), combining code will use *kernel's*, i.e. *wide* longs
* for hi and lo.
*/
SYS_FUNC(llseek)
{
if (entering(tcp)) {
/* fd */
printfd(tcp, tcp->u_arg[0]);
tprint_arg_next();
long long offset = ((long long) tcp->u_arg[1] << 32) |
((long long) tcp->u_arg[2]);
/* offset */
PRINT_VAL_D(offset);
tprint_arg_next();
} else {
/* result */
printnum_int64(tcp, tcp->u_arg[3], "%" PRIu64);
tprint_arg_next();
/* whence */
printxval(whence_codes, tcp->u_arg[4], "SEEK_???");
}
return 0;
}
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