1 /*
2 * Copyright (c) 1998 Michael Smith.
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 /*
29 * Manage an environment-like space in which string variables may be stored.
30 * Provide support for some method-like operations for setting/retrieving
31 * variables in order to allow some type strength.
32 */
33
34 #include "stand.h"
35
36 #include <string.h>
37
38 struct env_var *environ = NULL;
39
40 /*
41 * Look up (name) and return it's env_var structure.
42 */
43 struct env_var *
env_getenv(const char * name)44 env_getenv(const char *name)
45 {
46 struct env_var *ev;
47
48 for (ev = environ; ev != NULL; ev = ev->ev_next)
49 if (!strcmp(ev->ev_name, name))
50 break;
51 return (ev);
52 }
53
54 /*
55 * Some notes:
56 *
57 * If the EV_VOLATILE flag is set, a copy of the variable is made.
58 * If EV_DYNAMIC is set, the variable has been allocated with
59 * malloc and ownership transferred to the environment.
60 * If (value) is NULL, the variable is set but has no value.
61 */
62 int
env_setenv(const char * name,int flags,const void * value,ev_sethook_t sethook,ev_unsethook_t unsethook)63 env_setenv(const char *name, int flags, const void *value,
64 ev_sethook_t sethook, ev_unsethook_t unsethook)
65 {
66 struct env_var *ev, *curr, *last;
67
68 if ((ev = env_getenv(name)) != NULL) {
69 /*
70 * If there's a set hook, let it do the work
71 * (unless we are working for one already).
72 */
73 if ((ev->ev_sethook != NULL) && !(flags & EV_NOHOOK))
74 return (ev->ev_sethook(ev, flags, value));
75
76 /* If there is data in the variable, discard it. */
77 if (ev->ev_value != NULL && (ev->ev_flags & EV_DYNAMIC) != 0)
78 free(ev->ev_value);
79 ev->ev_value = NULL;
80 ev->ev_flags &= ~EV_DYNAMIC;
81
82 } else {
83
84 /*
85 * New variable; create and sort into list
86 */
87 ev = malloc(sizeof(struct env_var));
88 ev->ev_name = strdup(name);
89 ev->ev_value = NULL;
90 ev->ev_flags = 0;
91 /* hooks can only be set when the variable is instantiated */
92 ev->ev_sethook = sethook;
93 ev->ev_unsethook = unsethook;
94
95 /* Sort into list */
96 ev->ev_prev = NULL;
97 ev->ev_next = NULL;
98 /* Search for the record to insert before */
99 for (last = NULL, curr = environ; curr != NULL;
100 last = curr, curr = curr->ev_next) {
101
102 if (strcmp(ev->ev_name, curr->ev_name) < 0) {
103 if (curr->ev_prev) {
104 curr->ev_prev->ev_next = ev;
105 } else {
106 environ = ev;
107 }
108 ev->ev_next = curr;
109 ev->ev_prev = curr->ev_prev;
110 curr->ev_prev = ev;
111 break;
112 }
113 }
114 if (curr == NULL) {
115 if (last == NULL) {
116 environ = ev;
117 } else {
118 last->ev_next = ev;
119 ev->ev_prev = last;
120 }
121 }
122 }
123
124 /* If we have a new value, use it */
125 if (flags & EV_VOLATILE) {
126 ev->ev_value = strdup(value);
127 ev->ev_flags |= EV_DYNAMIC;
128 } else {
129 ev->ev_value = (char *)value;
130 ev->ev_flags |= flags & EV_DYNAMIC;
131 }
132
133 return (0);
134 }
135
136 /* coverity[ -tainted_string_return_content ] */
137 char *
getenv(const char * name)138 getenv(const char *name)
139 {
140 struct env_var *ev;
141
142 /* Set but no value gives empty string */
143 if ((ev = env_getenv(name)) != NULL) {
144 if (ev->ev_value != NULL)
145 return (ev->ev_value);
146 return ("");
147 }
148 return (NULL);
149 }
150
151 int
setenv(const char * name,const char * value,int overwrite)152 setenv(const char *name, const char *value, int overwrite)
153 {
154 /* No guarantees about state, always assume volatile */
155 if (overwrite || (env_getenv(name) == NULL))
156 return (env_setenv(name, EV_VOLATILE, value, NULL, NULL));
157 return (0);
158 }
159
160 int
putenv(char * string)161 putenv(char *string)
162 {
163 char *value, *copy;
164 int result;
165
166 copy = strdup(string);
167 if ((value = strchr(copy, '=')) != NULL)
168 *(value++) = 0;
169 result = setenv(copy, value, 1);
170 free(copy);
171 return (result);
172 }
173
174 int
unsetenv(const char * name)175 unsetenv(const char *name)
176 {
177 struct env_var *ev;
178 int err;
179
180 err = 0;
181 if ((ev = env_getenv(name)) == NULL) {
182 err = ENOENT;
183 } else {
184 if (ev->ev_unsethook != NULL)
185 err = ev->ev_unsethook(ev);
186 if (err == 0) {
187 env_discard(ev);
188 }
189 }
190 return (err);
191 }
192
193 void
env_discard(struct env_var * ev)194 env_discard(struct env_var *ev)
195 {
196 if (ev->ev_prev)
197 ev->ev_prev->ev_next = ev->ev_next;
198 if (ev->ev_next)
199 ev->ev_next->ev_prev = ev->ev_prev;
200 if (environ == ev)
201 environ = ev->ev_next;
202 free(ev->ev_name);
203 if (ev->ev_value != NULL && (ev->ev_flags & EV_DYNAMIC) != 0)
204 free(ev->ev_value);
205 free(ev);
206 }
207
208 int
env_noset(struct env_var * ev __unused,int flags __unused,const void * value __unused)209 env_noset(struct env_var *ev __unused, int flags __unused,
210 const void *value __unused)
211 {
212 return (EPERM);
213 }
214
215 int
env_nounset(struct env_var * ev __unused)216 env_nounset(struct env_var *ev __unused)
217 {
218 return (EPERM);
219 }
220