1 /*
2 * Copyright (c) 1987 Regents of the University of California.
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 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34 #if defined(LIBC_SCCS) && !defined(lint)
35 static char sccsid[] = "@(#)getenv.c 5.8 (Berkeley) 2/23/91";
36 #endif /* LIBC_SCCS and not lint */
37
38 #include <stdlib.h>
39 #include <stddef.h>
40 #include <string.h>
41
42 /*
43 * getenv --
44 * Returns ptr to value associated with name, if any, else NULL.
45 */
46 char *
getenv(name)47 getenv(name)
48 const char *name;
49 {
50 int offset;
51 char *_findenv();
52
53 return(_findenv(name, &offset));
54 }
55
56 /*
57 * _findenv --
58 * Returns pointer to value associated with name, if any, else NULL.
59 * Sets offset to be the offset of the name/value combination in the
60 * environmental array, for use by setenv(3) and unsetenv(3).
61 * Explicitly removes '=' in argument name.
62 *
63 * This routine *should* be a static; don't use it.
64 */
65 char *
_findenv(name,offset)66 _findenv(name, offset)
67 register char *name;
68 int *offset;
69 {
70 extern char **environ;
71 register int len;
72 register char **P, *C;
73
74 for (C = name, len = 0; *C && *C != '='; ++C, ++len);
75 for (P = environ; *P; ++P)
76 if (!strncmp(*P, name, len))
77 if (*(C = *P + len) == '=') {
78 *offset = P - environ;
79 return(++C);
80 }
81 return(NULL);
82 }
83