xref: /titanic_52/usr/src/cmd/dtrace/test/cmd/badioctl/badioctl.c (revision 7014882c6a3672fd0e5d60200af8643ae53c5928)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 #include <sys/stat.h>
30 #include <stdio.h>
31 #include <stdlib.h>
32 #include <fcntl.h>
33 #include <sys/varargs.h>
34 #include <errno.h>
35 #include <sys/mman.h>
36 #include <sys/wait.h>
37 #include <unistd.h>
38 
39 #define	DTRACEIOC	(('d' << 24) | ('t' << 16) | ('r' << 8))
40 #define	DTRACEIOC_MAX	17
41 
42 void
43 fatal(char *fmt, ...)
44 {
45 	va_list ap;
46 
47 	va_start(ap, fmt);
48 
49 	fprintf(stderr, "%s: ", "badioctl");
50 	vfprintf(stderr, fmt, ap);
51 
52 	if (fmt[strlen(fmt) - 1] != '\n')
53 		fprintf(stderr, ": %s\n", strerror(errno));
54 
55 	exit(1);
56 }
57 
58 void
59 badioctl(pid_t parent)
60 {
61 	int fd = -1, random, ps = sysconf(_SC_PAGESIZE);
62 	int i = 0, seconds;
63 	caddr_t addr;
64 	hrtime_t now, last = 0, end;
65 
66 	if ((random = open("/dev/random", O_RDONLY)) == -1)
67 		fatal("couldn't open /dev/random");
68 
69 	if ((addr = mmap(0, ps, PROT_READ | PROT_WRITE,
70 	    MAP_ANON | MAP_PRIVATE, -1, 0)) == (caddr_t)-1)
71 		fatal("mmap");
72 
73 	for (;;) {
74 		unsigned int ioc;
75 
76 		if ((now = gethrtime()) - last > NANOSEC) {
77 			if (kill(parent, 0) == -1 && errno == ESRCH) {
78 				/*
79 				 * Our parent died.  We will kill ourselves in
80 				 * sympathy.
81 				 */
82 				exit(0);
83 			}
84 
85 			/*
86 			 * Once a second, we'll reopen the device.
87 			 */
88 			if (fd != -1)
89 				close(fd);
90 
91 			fd = open("/devices/pseudo/dtrace@0:dtrace", O_RDONLY);
92 
93 			if (fd == -1)
94 				fatal("couldn't open DTrace pseudo device");
95 
96 			last = now;
97 		}
98 
99 
100 		if ((i++ % 1000) == 0) {
101 			/*
102 			 * Every thousand iterations, change our random gunk.
103 			 */
104 			read(random, addr, ps);
105 		}
106 
107 		read(random, &ioc, sizeof (ioc));
108 		ioc %= DTRACEIOC_MAX;
109 		ioc++;
110 		ioctl(fd, DTRACEIOC | ioc, addr);
111 	}
112 }
113 
114 int
115 main()
116 {
117 	pid_t child, parent = getpid();
118 	int status;
119 
120 	for (;;) {
121 		if ((child = fork()) == 0)
122 			badioctl(parent);
123 
124 		while (waitpid(child, &status, WEXITED) != child)
125 			continue;
126 
127 		if (WIFEXITED(status)) {
128 			/*
129 			 * Our child exited by design -- we'll exit with
130 			 * the same status code.
131 			 */
132 			exit(WEXITSTATUS(status));
133 		}
134 
135 		/*
136 		 * Our child died on a signal.  Respawn it.
137 		 */
138 		printf("badioctl: child died on signal %d; respawning.\n",
139 		    WTERMSIG(status));
140 		fflush(stdout);
141 	}
142 
143 	/* NOTREACHED */
144 	return (0);
145 }
146