1 /*
2  * Copyright (c) 2015 Dmitry V. Levin <ldv@altlinux.org>
3  * Copyright (c) 2015-2017 The strace developers.
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  * 3. The name of the author may not be used to endorse or promote products
15  *    derived from this software without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 #include "defs.h"
30 #include "print_fields.h"
31 #include "xlat/kcmp_types.h"
32 
33 struct strace_kcmp_epoll_slot {
34 	uint32_t efd;
35 	uint32_t tfd;
36 	uint32_t toff;
37 };
38 
39 static void
printpidfd(struct tcb * tcp,pid_t pid,int fd)40 printpidfd(struct tcb *tcp, pid_t pid, int fd)
41 {
42 	/*
43 	 * XXX We want to use printfd here, but we should figure out which
44 	 *     process in strace's PID NS is referred to first.
45 	 */
46 	tprintf("%d", fd);
47 }
48 
49 #define PRINT_FIELD_PIDFD(prefix_, where_, field_, tcp_, pid_)		\
50 	do {								\
51 		STRACE_PRINTF("%s%s=", (prefix_), #field_);		\
52 		printpidfd((tcp_), (pid_), (where_).field_);		\
53 	} while (0)
54 
SYS_FUNC(kcmp)55 SYS_FUNC(kcmp)
56 {
57 	pid_t pid1 = tcp->u_arg[0];
58 	pid_t pid2 = tcp->u_arg[1];
59 	int type = tcp->u_arg[2];
60 	kernel_ulong_t idx1 = tcp->u_arg[3];
61 	kernel_ulong_t idx2 = tcp->u_arg[4];
62 
63 	tprintf("%d, %d, ", pid1, pid2);
64 	printxval(kcmp_types, type, "KCMP_???");
65 
66 	switch (type) {
67 		case KCMP_FILE:
68 			tprints(", ");
69 			printpidfd(tcp, pid1, idx1);
70 			tprints(", ");
71 			printpidfd(tcp, pid1, idx2);
72 
73 			break;
74 
75 		case KCMP_EPOLL_TFD: {
76 			struct strace_kcmp_epoll_slot slot;
77 
78 			tprints(", ");
79 			printpidfd(tcp, pid1, idx1);
80 			tprints(", ");
81 
82 			if (umove_or_printaddr(tcp, idx2, &slot))
83 				break;
84 
85 			PRINT_FIELD_PIDFD("{",  slot, efd, tcp, pid2);
86 			PRINT_FIELD_PIDFD(", ", slot, tfd, tcp, pid2);
87 			PRINT_FIELD_U(", ", slot, toff);
88 			tprints("}");
89 
90 			break;
91 		}
92 
93 		case KCMP_FILES:
94 		case KCMP_FS:
95 		case KCMP_IO:
96 		case KCMP_SIGHAND:
97 		case KCMP_SYSVSEM:
98 		case KCMP_VM:
99 			break;
100 		default:
101 			tprintf(", %#" PRI_klx ", %#" PRI_klx, idx1, idx2);
102 	}
103 
104 	return RVAL_DECODED;
105 }
106