1 /* $OpenBSD: getenv.c,v 1.10 2010/08/23 22:31:50 millert Exp $ */ 2 /* 3 * Copyright (c) 1987, 1993 4 * The Regents of the University of California. 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 <stdlib.h> 32 #include <string.h> 33 34 char *__findenv(const char *name, int len, int *offset); 35 36 /* 37 * __findenv -- 38 * Returns pointer to value associated with name, if any, else NULL. 39 * Starts searching within the environmental array at offset. 40 * Sets offset to be the offset of the name/value combination in the 41 * environmental array, for use by putenv(3), setenv(3) and unsetenv(3). 42 * Explicitly removes '=' in argument name. 43 * 44 * This routine *should* be a static; don't use it. 45 */ 46 char * 47 __findenv(const char *name, int len, int *offset) 48 { 49 extern char **environ; 50 int i; 51 const char *np; 52 char **p, *cp; 53 54 if (name == NULL || environ == NULL) 55 return (NULL); 56 for (p = environ + *offset; (cp = *p) != NULL; ++p) { 57 for (np = name, i = len; i && *cp; i--) 58 if (*cp++ != *np++) 59 break; 60 if (i == 0 && *cp++ == '=') { 61 *offset = p - environ; 62 return (cp); 63 } 64 } 65 return (NULL); 66 } 67 68 /* 69 * getenv -- 70 * Returns ptr to value associated with name, if any, else NULL. 71 */ 72 char * 73 getenv(const char *name) 74 { 75 int offset = 0; 76 const char *np; 77 78 for (np = name; *np && *np != '='; ++np) 79 ; 80 return (__findenv(name, (int)(np - name), &offset)); 81 } 82
