xref: /freebsd/sbin/ddb/ddb_script.c (revision dd41de95a84d979615a2ef11df6850622bf6184e)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2007 Robert N. M. Watson
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include <sys/types.h>
33 #include <sys/sysctl.h>
34 
35 #include <err.h>
36 #include <errno.h>
37 #include <stdio.h>
38 #include <stdlib.h>
39 #include <string.h>
40 #include <sysexits.h>
41 
42 #include "ddb.h"
43 
44 /*
45  * These commands manage DDB(4) scripts from user space.  For better or worse,
46  * the setting and unsetting of scripts is only poorly represented using
47  * sysctl(8), and this interface provides a more user-friendly way to
48  * accomplish this management, wrapped around lower-level sysctls.  For
49  * completeness, listing of scripts is also included.
50  */
51 
52 #define	SYSCTL_SCRIPT	"debug.ddb.scripting.script"
53 #define	SYSCTL_SCRIPTS	"debug.ddb.scripting.scripts"
54 #define	SYSCTL_UNSCRIPT	"debug.ddb.scripting.unscript"
55 
56 /*
57  * Print all scripts (scriptname==NULL) or a specific script.
58  */
59 static void
60 ddb_list_scripts(const char *scriptname)
61 {
62 	char *buffer, *line, *nextline;
63 	char *line_script, *line_scriptname;
64 	size_t buflen, len;
65 	int ret;
66 
67 repeat:
68 	if (sysctlbyname(SYSCTL_SCRIPTS, NULL, &buflen, NULL, 0) < 0)
69 		err(EX_OSERR, "sysctl: %s", SYSCTL_SCRIPTS);
70 	if (buflen == 0)
71 		return;
72 	buffer = malloc(buflen);
73 	if (buffer == NULL)
74 		err(EX_OSERR, "malloc");
75 	bzero(buffer, buflen);
76 	len = buflen;
77 	ret = sysctlbyname(SYSCTL_SCRIPTS, buffer, &len, NULL, 0);
78 	if (ret < 0 && errno != ENOMEM)
79 		err(EX_OSERR, "sysctl: %s", SYSCTL_SCRIPTS);
80 	if (ret < 0) {
81 		free(buffer);
82 		goto repeat;
83 	}
84 
85 	/*
86 	 * We nul'd the buffer before calling sysctl(), so at worst empty.
87 	 *
88 	 * If a specific script hasn't been requested, print it all.
89 	 */
90 	if (scriptname == NULL) {
91 		printf("%s", buffer);
92 		free(buffer);
93 		return;
94 	}
95 
96 	/*
97 	 * If a specific script has been requested, we have to parse the
98 	 * string to find it.
99 	 */
100 	nextline = buffer;
101 	while ((line = strsep(&nextline, "\n")) != NULL) {
102 		line_script = line;
103 		line_scriptname = strsep(&line_script, "=");
104 		if (line_script == NULL)
105 			continue;
106 		if (strcmp(scriptname, line_scriptname) != 0)
107 			continue;
108 		printf("%s\n", line_script);
109 		break;
110 	}
111 	if (line == NULL) {
112 		errno = ENOENT;
113 		err(EX_DATAERR, "%s", scriptname);
114 	}
115 	free(buffer);
116 }
117 
118 /*
119  * "ddb script" can be used to either print or set a script.
120  */
121 void
122 ddb_script(int argc, char *argv[])
123 {
124 
125 	if (argc != 2)
126 		usage();
127 	argv++;
128 	argc--;
129 	if (strchr(argv[0], '=') != 0) {
130 		if (sysctlbyname(SYSCTL_SCRIPT, NULL, NULL, argv[0],
131 		    strlen(argv[0]) + 1) < 0)
132 			err(EX_OSERR, "sysctl: %s", SYSCTL_SCRIPTS);
133 	} else
134 		ddb_list_scripts(argv[0]);
135 }
136 
137 void
138 ddb_scripts(int argc, char *argv[] __unused)
139 {
140 
141 	if (argc != 1)
142 		usage();
143 	ddb_list_scripts(NULL);
144 }
145 
146 void
147 ddb_unscript(int argc, char *argv[])
148 {
149 	int ret;
150 
151 	if (argc != 2)
152 		usage();
153 	argv++;
154 	argc--;
155 	ret = sysctlbyname(SYSCTL_UNSCRIPT, NULL, NULL, argv[0],
156 	    strlen(argv[0]) + 1);
157 	if (ret < 0 && errno == EINVAL) {
158 		errno = ENOENT;
159 		err(EX_DATAERR, "sysctl: %s", argv[0]);
160 	} else if (ret < 0)
161 		err(EX_OSERR, "sysctl: %s", SYSCTL_UNSCRIPT);
162 }
163