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 are permitted 6 * provided that the above copyright notice and this paragraph are 7 * duplicated in all such forms and that any documentation, 8 * advertising materials, and other materials related to such 9 * distribution and use acknowledge that the software was developed 10 * by the University of California, Berkeley. The name of the 11 * University may not be used to endorse or promote products derived 12 * from this software without specific prior written permission. 13 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR 14 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 15 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. 16 */ 17 18 #if defined(LIBC_SCCS) && !defined(lint) 19 static char sccsid[] = "@(#)getenv.c 5.5 (Berkeley) 06/27/88"; 20 #endif /* LIBC_SCCS and not lint */ 21 22 #include <stdio.h> 23 24 /* 25 * getenv -- 26 * Returns ptr to value associated with name, if any, else NULL. 27 */ 28 char * 29 getenv(name) 30 char *name; 31 { 32 int offset; 33 char *_findenv(); 34 35 return(_findenv(name, &offset)); 36 } 37 38 /* 39 * _findenv -- 40 * Returns pointer to value associated with name, if any, else NULL. 41 * Sets offset to be the offset of the name/value combination in the 42 * environmental array, for use by setenv(3) and unsetenv(3). 43 * Explicitly removes '=' in argument name. 44 * 45 * This routine *should* be a static; don't use it. 46 */ 47 char * 48 _findenv(name, offset) 49 register char *name; 50 int *offset; 51 { 52 extern char **environ; 53 register int len; 54 register char **P, *C; 55 56 for (C = name, len = 0; *C && *C != '='; ++C, ++len); 57 for (P = environ; *P; ++P) 58 if (!strncmp(*P, name, len)) 59 if (*(C = *P + len) == '=') { 60 *offset = P - environ; 61 return(++C); 62 } 63 return(NULL); 64 } 65