xref: /freebsd/usr.sbin/autofs/defined.c (revision 32100375a661c1e16588ddfa7b90ca8d26cb9786)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2014 The FreeBSD Foundation
5  * All rights reserved.
6  *
7  * This software was developed by Edward Tomasz Napierala under sponsorship
8  * from the FreeBSD Foundation.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  *
31  */
32 
33 /*
34  * All the "defined" stuff is for handling variables,
35  * such as ${OSNAME}, in maps.
36  */
37 
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
40 
41 #include <sys/types.h>
42 #include <sys/time.h>
43 #include <sys/ioctl.h>
44 #include <sys/param.h>
45 #include <sys/linker.h>
46 #include <sys/mount.h>
47 #include <sys/socket.h>
48 #include <sys/stat.h>
49 #include <sys/wait.h>
50 #include <sys/utsname.h>
51 #include <assert.h>
52 #include <ctype.h>
53 #include <errno.h>
54 #include <fcntl.h>
55 #include <libgen.h>
56 #include <libutil.h>
57 #include <netdb.h>
58 #include <signal.h>
59 #include <stdbool.h>
60 #include <stdint.h>
61 #include <stdio.h>
62 #include <stdlib.h>
63 #include <string.h>
64 #include <unistd.h>
65 
66 #include "common.h"
67 
68 static TAILQ_HEAD(, defined_value)	defined_values;
69 
70 static const char *
71 defined_find(const char *name)
72 {
73 	struct defined_value *d;
74 
75 	TAILQ_FOREACH(d, &defined_values, d_next) {
76 		if (strcmp(d->d_name, name) == 0)
77 			return (d->d_value);
78 	}
79 
80 	return (NULL);
81 }
82 
83 char *
84 defined_expand(const char *string)
85 {
86 	const char *value;
87 	char c, *expanded, *name;
88 	int i, ret, before_len = 0, name_off = 0, name_len = 0, after_off = 0;
89 	bool backslashed = false, bracketed = false;
90 
91 	expanded = checked_strdup(string);
92 
93 	for (i = 0; string[i] != '\0'; i++) {
94 		c = string[i];
95 		if (c == '\\' && backslashed == false) {
96 			backslashed = true;
97 			continue;
98 		}
99 		if (backslashed) {
100 			backslashed = false;
101 			continue;
102 		}
103 		backslashed = false;
104 		if (c != '$')
105 			continue;
106 
107 		/*
108 		 * The 'before_len' variable contains the number
109 		 * of characters before the '$'.
110 		 */
111 		before_len = i;
112 		assert(i + 1 < (int)strlen(string));
113 		if (string[i + 1] == '{')
114 			bracketed = true;
115 
116 		if (string[i + 1] == '\0') {
117 			log_warnx("truncated variable");
118 			return (NULL);
119 		}
120 
121 		/*
122 		 * Skip '$'.
123 		 */
124 		i++;
125 
126 		if (bracketed) {
127 			if (string[i + 1] == '\0') {
128 				log_warnx("truncated variable");
129 				return (NULL);
130 			}
131 
132 			/*
133 			 * Skip '{'.
134 			 */
135 			i++;
136 		}
137 
138 		/*
139 		 * The 'name_off' variable contains the number
140 		 * of characters before the variable name,
141 		 * including the "$" or "${".
142 		 */
143 		name_off = i;
144 
145 		for (; string[i] != '\0'; i++) {
146 			c = string[i];
147 			/*
148 			 * XXX: Decide on the set of characters that can be
149 			 *	used in a variable name.
150 			 */
151 			if (isalnum(c) || c == '_')
152 				continue;
153 
154 			/*
155 			 * End of variable name.
156 			 */
157 			if (bracketed) {
158 				if (c != '}')
159 					continue;
160 
161 				/*
162 				 * The 'after_off' variable contains the number
163 				 * of characters before the rest of the string,
164 				 * i.e. after the variable name.
165 				 */
166 				after_off = i + 1;
167 				assert(i > 1);
168 				assert(i - 1 > name_off);
169 				name_len = i - name_off;
170 				break;
171 			}
172 
173 			after_off = i;
174 			assert(i > 1);
175 			assert(i > name_off);
176 			name_len = i - name_off;
177 			break;
178 		}
179 
180 		name = strndup(string + name_off, name_len);
181 		if (name == NULL)
182 			log_err(1, "strndup");
183 		value = defined_find(name);
184 		if (value == NULL) {
185 			log_warnx("undefined variable ${%s}", name);
186 			return (NULL);
187 		}
188 
189 		/*
190 		 * Concatenate it back.
191 		 */
192 		ret = asprintf(&expanded, "%.*s%s%s",
193 		    before_len, string, value, string + after_off);
194 		if (ret < 0)
195 			log_err(1, "asprintf");
196 
197 		//log_debugx("\"%s\" expanded to \"%s\"", string, expanded);
198 		free(name);
199 
200 		/*
201 		 * Figure out where to start searching for next variable.
202 		 */
203 		string = expanded;
204 		i = before_len + strlen(value);
205 		backslashed = bracketed = false;
206 		before_len = name_off = name_len = after_off = 0;
207 		assert(i <= (int)strlen(string));
208 	}
209 
210 	if (before_len != 0 || name_off != 0 || name_len != 0 || after_off != 0) {
211 		log_warnx("truncated variable");
212 		return (NULL);
213 	}
214 
215 	return (expanded);
216 }
217 
218 static void
219 defined_add(const char *name, const char *value)
220 {
221 	struct defined_value *d;
222 	const char *found;
223 
224 	found = defined_find(name);
225 	if (found != NULL)
226 		log_errx(1, "variable %s already defined", name);
227 
228 	log_debugx("defining variable %s=%s", name, value);
229 
230 	d = calloc(1, sizeof(*d));
231 	if (d == NULL)
232 		log_err(1, "calloc");
233 	d->d_name = checked_strdup(name);
234 	d->d_value = checked_strdup(value);
235 
236 	TAILQ_INSERT_TAIL(&defined_values, d, d_next);
237 }
238 
239 void
240 defined_parse_and_add(char *def)
241 {
242 	char *name, *value;
243 
244 	value = def;
245 	name = strsep(&value, "=");
246 
247 	if (value == NULL || value[0] == '\0')
248 		log_errx(1, "missing variable value");
249 	if (name == NULL || name[0] == '\0')
250 		log_errx(1, "missing variable name");
251 
252 	defined_add(name, value);
253 }
254 
255 void
256 defined_init(void)
257 {
258 	struct utsname name;
259 	int error;
260 
261 	TAILQ_INIT(&defined_values);
262 
263 	error = uname(&name);
264 	if (error != 0)
265 		log_err(1, "uname");
266 
267 	defined_add("ARCH", name.machine);
268 	defined_add("CPU", name.machine);
269 	defined_add("DOLLAR", "$");
270 	defined_add("HOST", name.nodename);
271 	defined_add("OSNAME", name.sysname);
272 	defined_add("OSREL", name.release);
273 	defined_add("OSVERS", name.version);
274 }
275