1 /* $OpenBSD: setenv.c,v 1.20 2022/08/08 22:40:03 millert Exp $ */
2 /*
3 * Copyright (c) 1987 Regents of the University of California.
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of the University nor the names of its contributors
15 * may be used to endorse or promote products derived from this software
16 * without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31 #include <errno.h>
32 #include <stdlib.h>
33 #include <string.h>
34
35 static char **lastenv; /* last value of environ */
36
37 /*
38 * putenv --
39 * Add a name=value string directly to the environmental, replacing
40 * any current value.
41 */
42 int
putenv(char * str)43 putenv(char *str)
44 {
45 char **P, *cp;
46 size_t cnt = 0;
47 int offset = 0;
48
49 for (cp = str; *cp && *cp != '='; ++cp)
50 ;
51 if (cp == str || *cp != '=') {
52 /* '=' is the first character of string or is missing. */
53 errno = EINVAL;
54 return (-1);
55 }
56
57 if (__findenv(str, (int)(cp - str), &offset) != NULL) {
58 environ[offset++] = str;
59 /* could be set multiple times */
60 while (__findenv(str, (int)(cp - str), &offset)) {
61 for (P = &environ[offset];; ++P)
62 if (!(*P = *(P + 1)))
63 break;
64 }
65 return (0);
66 }
67
68 /* create new slot for string */
69 if (environ != NULL) {
70 for (P = environ; *P != NULL; P++)
71 ;
72 cnt = P - environ;
73 }
74 P = reallocarray(lastenv, cnt + 2, sizeof(char *));
75 if (!P)
76 return (-1);
77 if (lastenv != environ && environ != NULL)
78 memcpy(P, environ, cnt * sizeof(char *));
79 lastenv = environ = P;
80 environ[cnt] = str;
81 environ[cnt + 1] = NULL;
82 return (0);
83 }
84 DEF_WEAK(putenv);
85
86 /*
87 * setenv --
88 * Set the value of the environmental variable "name" to be
89 * "value". If rewrite is set, replace any current value.
90 */
91 int
setenv(const char * name,const char * value,int rewrite)92 setenv(const char *name, const char *value, int rewrite)
93 {
94 char *C, **P;
95 const char *np;
96 int l_value, offset = 0;
97
98 if (!name || !*name) {
99 errno = EINVAL;
100 return (-1);
101 }
102 for (np = name; *np && *np != '='; ++np)
103 ;
104 if (*np) {
105 errno = EINVAL;
106 return (-1); /* has `=' in name */
107 }
108
109 l_value = strlen(value);
110 if ((C = __findenv(name, (int)(np - name), &offset)) != NULL) {
111 int tmpoff = offset + 1;
112 if (!rewrite)
113 return (0);
114 #if 0 /* XXX - existing entry may not be writable */
115 if (strlen(C) >= l_value) { /* old larger; copy over */
116 while ((*C++ = *value++))
117 ;
118 return (0);
119 }
120 #endif
121 /* could be set multiple times */
122 while (__findenv(name, (int)(np - name), &tmpoff)) {
123 for (P = &environ[tmpoff];; ++P)
124 if (!(*P = *(P + 1)))
125 break;
126 }
127 } else { /* create new slot */
128 size_t cnt = 0;
129
130 if (environ != NULL) {
131 for (P = environ; *P != NULL; P++)
132 ;
133 cnt = P - environ;
134 }
135 P = reallocarray(lastenv, cnt + 2, sizeof(char *));
136 if (!P)
137 return (-1);
138 if (lastenv != environ && environ != NULL)
139 memcpy(P, environ, cnt * sizeof(char *));
140 lastenv = environ = P;
141 offset = cnt;
142 environ[cnt + 1] = NULL;
143 }
144 if (!(environ[offset] = /* name + `=' + value */
145 malloc((int)(np - name) + l_value + 2)))
146 return (-1);
147 for (C = environ[offset]; (*C = *name++) && *C != '='; ++C)
148 ;
149 for (*C++ = '='; (*C++ = *value++); )
150 ;
151 return (0);
152 }
153 DEF_WEAK(setenv);
154
155 /*
156 * unsetenv(name) --
157 * Delete environmental variable "name".
158 */
159 int
unsetenv(const char * name)160 unsetenv(const char *name)
161 {
162 char **P;
163 const char *np;
164 int offset = 0;
165
166 if (!name || !*name) {
167 errno = EINVAL;
168 return (-1);
169 }
170 for (np = name; *np && *np != '='; ++np)
171 ;
172 if (*np) {
173 errno = EINVAL;
174 return (-1); /* has `=' in name */
175 }
176
177 /* could be set multiple times */
178 while (__findenv(name, (int)(np - name), &offset)) {
179 for (P = &environ[offset];; ++P)
180 if (!(*P = *(P + 1)))
181 break;
182 }
183 return (0);
184 }
185 DEF_WEAK(unsetenv);
186