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      1 /*
      2  * Copyright (c) 1991, 1992 Paul Kranenburg <pk (at) cs.few.eur.nl>
      3  * Copyright (c) 1993 Branko Lankester <branko (at) hacktic.nl>
      4  * Copyright (c) 1993, 1994, 1995, 1996 Rick Sladkey <jrs (at) world.std.com>
      5  * Copyright (c) 1996-1999 Wichert Akkerman <wichert (at) cistron.nl>
      6  * Copyright (c) 2002-2005 Roland McGrath <roland (at) redhat.com>
      7  * Copyright (c) 2009 Andreas Schwab <schwab (at) redhat.com>
      8  * Copyright (c) 2012 H.J. Lu <hongjiu.lu (at) intel.com>
      9  * Copyright (c) 2013 Denys Vlasenko <vda.linux (at) googlemail.com>
     10  * Copyright (c) 2014-2015 Dmitry V. Levin <ldv (at) altlinux.org>
     11  * All rights reserved.
     12  *
     13  * Redistribution and use in source and binary forms, with or without
     14  * modification, are permitted provided that the following conditions
     15  * are met:
     16  * 1. Redistributions of source code must retain the above copyright
     17  *    notice, this list of conditions and the following disclaimer.
     18  * 2. Redistributions in binary form must reproduce the above copyright
     19  *    notice, this list of conditions and the following disclaimer in the
     20  *    documentation and/or other materials provided with the distribution.
     21  * 3. The name of the author may not be used to endorse or promote products
     22  *    derived from this software without specific prior written permission.
     23  *
     24  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     25  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     26  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     27  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     28  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     29  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     30  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     31  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     32  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     33  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     34  */
     35 
     36 #include "defs.h"
     37 
     38 #include "xlat/whence_codes.h"
     39 
     40 /* Linux kernel has exactly one version of lseek:
     41  * fs/read_write.c::SYSCALL_DEFINE3(lseek, unsigned, fd, off_t, offset, unsigned, origin)
     42  * In kernel, off_t is always the same as (kernel's) long
     43  * (see include/uapi/asm-generic/posix_types.h),
     44  * which means that on x32 we need to use tcp->ext_arg[N] to get offset argument.
     45  * Use test/x32_lseek.c to test lseek decoding.
     46  */
     47 #if defined(LINUX_MIPSN32) || defined(X32)
     48 SYS_FUNC(lseek)
     49 {
     50 	long long offset;
     51 	int whence;
     52 
     53 	printfd(tcp, tcp->u_arg[0]);
     54 # ifdef X32
     55 	/* tcp->ext_arg is not initialized for i386 personality */
     56 	if (current_personality == 1)
     57 		offset = tcp->u_arg[1];
     58 	else
     59 # endif
     60 	offset = tcp->ext_arg[1];
     61 	whence = tcp->u_arg[2];
     62 	if (whence == SEEK_SET)
     63 		tprintf(", %llu, ", offset);
     64 	else
     65 		tprintf(", %lld, ", offset);
     66 	printxval(whence_codes, whence, "SEEK_???");
     67 
     68 	return RVAL_DECODED | RVAL_LUDECIMAL;
     69 }
     70 #else
     71 SYS_FUNC(lseek)
     72 {
     73 	long offset;
     74 	int whence;
     75 
     76 	printfd(tcp, tcp->u_arg[0]);
     77 	offset = tcp->u_arg[1];
     78 	whence = tcp->u_arg[2];
     79 	if (whence == SEEK_SET)
     80 		tprintf(", %lu, ", offset);
     81 	else
     82 		tprintf(", %ld, ", offset);
     83 	printxval(whence_codes, whence, "SEEK_???");
     84 
     85 	return RVAL_DECODED | RVAL_UDECIMAL;
     86 }
     87 #endif
     88 
     89 /* llseek syscall takes explicitly two ulong arguments hi, lo,
     90  * rather than one 64-bit argument for which LONG_LONG works
     91  * appropriate for the native byte order.
     92  *
     93  * See kernel's fs/read_write.c::SYSCALL_DEFINE5(llseek, ...)
     94  *
     95  * hi,lo are "unsigned longs" and combined exactly this way in kernel:
     96  * ((loff_t) hi << 32) | lo
     97  * Note that for architectures with kernel's long wider than userspace long
     98  * (such as x32), combining code will use *kernel's*, i.e. *wide* longs
     99  * for hi and lo. We would need to use tcp->ext_arg[N] on x32...
    100  * ...however, x32 (and x86_64) does not _have_ llseek syscall as such.
    101  */
    102 SYS_FUNC(llseek)
    103 {
    104 	if (entering(tcp)) {
    105 		printfd(tcp, tcp->u_arg[0]);
    106 		if (tcp->u_arg[4] == SEEK_SET)
    107 			tprintf(", %llu, ",
    108 				((long long) tcp->u_arg[1]) << 32 |
    109 				(unsigned long long) (unsigned) tcp->u_arg[2]);
    110 		else
    111 			tprintf(", %lld, ",
    112 				((long long) tcp->u_arg[1]) << 32 |
    113 				(unsigned long long) (unsigned) tcp->u_arg[2]);
    114 	} else {
    115 		printnum_int64(tcp, tcp->u_arg[3], "%" PRIu64);
    116 		tprints(", ");
    117 		printxval(whence_codes, tcp->u_arg[4], "SEEK_???");
    118 	}
    119 	return 0;
    120 }
    121