1 /*
2 * Copyright (c) 1991, 1992 Paul Kranenburg <pk@cs.few.eur.nl>
3 * Copyright (c) 1993 Branko Lankester <branko@hacktic.nl>
4 * Copyright (c) 1993, 1994, 1995, 1996 Rick Sladkey <jrs@world.std.com>
5 * Copyright (c) 1996-1999 Wichert Akkerman <wichert@cistron.nl>
6 * Copyright (c) 2002-2005 Roland McGrath <roland@redhat.com>
7 * Copyright (c) 2009 Andreas Schwab <schwab@redhat.com>
8 * Copyright (c) 2012 H.J. Lu <hongjiu.lu@intel.com>
9 * Copyright (c) 2013 Denys Vlasenko <vda.linux@googlemail.com>
10 * Copyright (c) 2014-2016 Dmitry V. Levin <ldv@altlinux.org>
11 * Copyright (c) 2014-2018 The strace developers.
12 * All rights reserved.
13 *
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions
16 * are met:
17 * 1. Redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer.
19 * 2. Redistributions in binary form must reproduce the above copyright
20 * notice, this list of conditions and the following disclaimer in the
21 * documentation and/or other materials provided with the distribution.
22 * 3. The name of the author may not be used to endorse or promote products
23 * derived from this software without specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
26 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
27 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
28 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
29 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
30 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
31 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
32 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
33 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
34 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
35 */
36
37 #include "defs.h"
38
39 #include "xlat/whence_codes.h"
40
41 /* Linux kernel has exactly one version of lseek:
42 * fs/read_write.c::SYSCALL_DEFINE3(lseek, unsigned, fd, off_t, offset, unsigned, origin)
43 * In kernel, off_t is always the same as (kernel's) long
44 * (see include/uapi/asm-generic/posix_types.h).
45 * Use test/x32_lseek.c to test lseek decoding.
46 */
SYS_FUNC(lseek)47 SYS_FUNC(lseek)
48 {
49 printfd(tcp, tcp->u_arg[0]);
50
51 kernel_long_t offset;
52
53 # ifndef current_klongsize
54 if (current_klongsize < sizeof(kernel_long_t)) {
55 offset = (int) tcp->u_arg[1];
56 } else
57 # endif /* !current_klongsize */
58 {
59 offset = tcp->u_arg[1];
60 }
61
62 tprintf(", %" PRI_kld ", ", offset);
63
64 printxval(whence_codes, tcp->u_arg[2], "SEEK_???");
65
66 return RVAL_DECODED;
67 }
68
69 /* llseek syscall takes explicitly two ulong arguments hi, lo,
70 * rather than one 64-bit argument for which ULONG_LONG works
71 * appropriate for the native byte order.
72 *
73 * See kernel's fs/read_write.c::SYSCALL_DEFINE5(llseek, ...)
74 *
75 * hi,lo are "unsigned longs" and combined exactly this way in kernel:
76 * ((loff_t) hi << 32) | lo
77 * Note that for architectures with kernel's long wider than userspace long
78 * (such as x32), combining code will use *kernel's*, i.e. *wide* longs
79 * for hi and lo.
80 */
SYS_FUNC(llseek)81 SYS_FUNC(llseek)
82 {
83 if (entering(tcp)) {
84 printfd(tcp, tcp->u_arg[0]);
85 tprintf(", %lld, ",
86 ((long long) tcp->u_arg[1] << 32)
87 | ((long long) tcp->u_arg[2]));
88 } else {
89 printnum_int64(tcp, tcp->u_arg[3], "%" PRIu64);
90 tprints(", ");
91 printxval(whence_codes, tcp->u_arg[4], "SEEK_???");
92 }
93 return 0;
94 }
95