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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) 2005-2007 Roland McGrath <roland@redhat.com>
7  * Copyright (c) 2006-2007 Ulrich Drepper <drepper@redhat.com>
8  * Copyright (c) 2009-2013 Denys Vlasenko <dvlasenk@redhat.com>
9  * Copyright (c) 2005-2015 Dmitry V. Levin <ldv@altlinux.org>
10  * Copyright (c) 2014-2018 The strace developers.
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 #include "xstring.h"
38 
39 #include <asm/fcntl.h>
40 
41 /* some libcs are guilty of messing up with O_ACCMODE */
42 #undef O_ACCMODE
43 #define O_ACCMODE 03
44 
45 #ifdef O_LARGEFILE
46 # if O_LARGEFILE == 0		/* biarch platforms in 64-bit mode */
47 #  undef O_LARGEFILE
48 # endif
49 #endif
50 
51 #include "xlat/open_access_modes.h"
52 #include "xlat/open_mode_flags.h"
53 
54 #ifndef AT_FDCWD
55 # define AT_FDCWD	-100
56 #endif
57 
58 /* The fd is an "int", so when decoding x86 on x86_64, we need to force sign
59  * extension to get the right value.  We do this by declaring fd as int here.
60  */
61 void
print_dirfd(struct tcb * tcp,int fd)62 print_dirfd(struct tcb *tcp, int fd)
63 {
64 	if (fd == AT_FDCWD)
65 		tprints("AT_FDCWD, ");
66 	else {
67 		printfd(tcp, fd);
68 		tprints(", ");
69 	}
70 }
71 
72 /*
73  * low bits of the open(2) flags define access mode,
74  * other bits are real flags.
75  */
76 const char *
sprint_open_modes(unsigned int flags)77 sprint_open_modes(unsigned int flags)
78 {
79 	static char outstr[(1 + ARRAY_SIZE(open_mode_flags)) * sizeof("O_LARGEFILE")];
80 	char *p;
81 	char sep;
82 	const char *str;
83 	const struct xlat *x;
84 
85 	sep = ' ';
86 	p = stpcpy(outstr, "flags");
87 	str = xlookup(open_access_modes, flags & 3);
88 	if (str) {
89 		*p++ = sep;
90 		p = stpcpy(p, str);
91 		flags &= ~3;
92 		if (!flags)
93 			return outstr;
94 		sep = '|';
95 	}
96 
97 	for (x = open_mode_flags; x->str; x++) {
98 		if ((flags & x->val) == x->val) {
99 			*p++ = sep;
100 			p = stpcpy(p, x->str);
101 			flags &= ~x->val;
102 			if (!flags)
103 				return outstr;
104 			sep = '|';
105 		}
106 	}
107 	/* flags is still nonzero */
108 	*p++ = sep;
109 	p = xappendstr(outstr, p, "%#x", flags);
110 	return outstr;
111 }
112 
113 void
tprint_open_modes(unsigned int flags)114 tprint_open_modes(unsigned int flags)
115 {
116 	tprints(sprint_open_modes(flags) + sizeof("flags"));
117 }
118 
119 #ifdef O_TMPFILE
120 /* The kernel & C libraries often inline O_DIRECTORY. */
121 # define STRACE_O_TMPFILE (O_TMPFILE & ~O_DIRECTORY)
122 #else /* !O_TMPFILE */
123 # define STRACE_O_TMPFILE 0
124 #endif
125 
126 static int
decode_open(struct tcb * tcp,int offset)127 decode_open(struct tcb *tcp, int offset)
128 {
129 	printpath(tcp, tcp->u_arg[offset]);
130 	tprints(", ");
131 	/* flags */
132 	tprint_open_modes(tcp->u_arg[offset + 1]);
133 	if (tcp->u_arg[offset + 1] & (O_CREAT | STRACE_O_TMPFILE)) {
134 		/* mode */
135 		tprints(", ");
136 		print_numeric_umode_t(tcp->u_arg[offset + 2]);
137 	}
138 
139 	return RVAL_DECODED | RVAL_FD;
140 }
141 
SYS_FUNC(open)142 SYS_FUNC(open)
143 {
144 	return decode_open(tcp, 0);
145 }
146 
SYS_FUNC(openat)147 SYS_FUNC(openat)
148 {
149 	print_dirfd(tcp, tcp->u_arg[0]);
150 	return decode_open(tcp, 1);
151 }
152 
SYS_FUNC(creat)153 SYS_FUNC(creat)
154 {
155 	printpath(tcp, tcp->u_arg[0]);
156 	tprints(", ");
157 	print_numeric_umode_t(tcp->u_arg[1]);
158 
159 	return RVAL_DECODED | RVAL_FD;
160 }
161