xref: /freebsd/sbin/ddb/ddb_script.c (revision 38f0b757fd84d17d0fc24739a7cda160c4516d81)
1 /*-
2  * Copyright (c) 2007 Robert N. M. Watson
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29 
30 #include <sys/types.h>
31 #include <sys/sysctl.h>
32 
33 #include <err.h>
34 #include <errno.h>
35 #include <stdio.h>
36 #include <stdlib.h>
37 #include <string.h>
38 #include <sysexits.h>
39 
40 #include "ddb.h"
41 
42 /*
43  * These commands manage DDB(4) scripts from user space.  For better or worse,
44  * the setting and unsetting of scripts is only poorly represented using
45  * sysctl(8), and this interface provides a more user-friendly way to
46  * accomplish this management, wrapped around lower-level sysctls.  For
47  * completeness, listing of scripts is also included.
48  */
49 
50 #define	SYSCTL_SCRIPT	"debug.ddb.scripting.script"
51 #define	SYSCTL_SCRIPTS	"debug.ddb.scripting.scripts"
52 #define	SYSCTL_UNSCRIPT	"debug.ddb.scripting.unscript"
53 
54 /*
55  * Print all scripts (scriptname==NULL) or a specific script.
56  */
57 static void
58 ddb_list_scripts(const char *scriptname)
59 {
60 	char *buffer, *line, *nextline;
61 	char *line_script, *line_scriptname;
62 	size_t buflen, len;
63 	int ret;
64 
65 repeat:
66 	if (sysctlbyname(SYSCTL_SCRIPTS, NULL, &buflen, NULL, 0) < 0)
67 		err(EX_OSERR, "sysctl: %s", SYSCTL_SCRIPTS);
68 	if (buflen == 0)
69 		return;
70 	buffer = malloc(buflen);
71 	if (buffer == NULL)
72 		err(EX_OSERR, "malloc");
73 	bzero(buffer, buflen);
74 	len = buflen;
75 	ret = sysctlbyname(SYSCTL_SCRIPTS, buffer, &len, NULL, 0);
76 	if (ret < 0 && errno != ENOMEM)
77 		err(EX_OSERR, "sysctl: %s", SYSCTL_SCRIPTS);
78 	if (ret < 0) {
79 		free(buffer);
80 		goto repeat;
81 	}
82 
83 	/*
84 	 * We nul'd the buffer before calling sysctl(), so at worst empty.
85 	 *
86 	 * If a specific script hasn't been requested, print it all.
87 	 */
88 	if (scriptname == NULL) {
89 		printf("%s", buffer);
90 		free(buffer);
91 		return;
92 	}
93 
94 	/*
95 	 * If a specific script has been requested, we have to parse the
96 	 * string to find it.
97 	 */
98 	nextline = buffer;
99 	while ((line = strsep(&nextline, "\n")) != NULL) {
100 		line_script = line;
101 		line_scriptname = strsep(&line_script, "=");
102 		if (line_script == NULL)
103 			continue;
104 		if (strcmp(scriptname, line_scriptname) != 0)
105 			continue;
106 		printf("%s\n", line_script);
107 		break;
108 	}
109 	if (line == NULL) {
110 		errno = ENOENT;
111 		err(EX_DATAERR, "%s", scriptname);
112 	}
113 	free(buffer);
114 }
115 
116 /*
117  * "ddb script" can be used to either print or set a script.
118  */
119 void
120 ddb_script(int argc, char *argv[])
121 {
122 
123 	if (argc != 2)
124 		usage();
125 	argv++;
126 	argc--;
127 	if (strchr(argv[0], '=') != 0) {
128 		if (sysctlbyname(SYSCTL_SCRIPT, NULL, NULL, argv[0],
129 		    strlen(argv[0]) + 1) < 0)
130 			err(EX_OSERR, "sysctl: %s", SYSCTL_SCRIPTS);
131 	} else
132 		ddb_list_scripts(argv[0]);
133 }
134 
135 void
136 ddb_scripts(int argc, char *argv[])
137 {
138 
139 	if (argc != 1)
140 		usage();
141 	ddb_list_scripts(NULL);
142 }
143 
144 void
145 ddb_unscript(int argc, char *argv[])
146 {
147 	int ret;
148 
149 	if (argc != 2)
150 		usage();
151 	argv++;
152 	argc--;
153 	ret = sysctlbyname(SYSCTL_UNSCRIPT, NULL, NULL, argv[0],
154 	    strlen(argv[0]) + 1);
155 	if (ret < 0 && errno == EINVAL) {
156 		errno = ENOENT;
157 		err(EX_DATAERR, "sysctl: %s", argv[0]);
158 	} else if (ret < 0)
159 		err(EX_OSERR, "sysctl: %s", SYSCTL_UNSCRIPT);
160 }
161