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 5.6 (Berkeley) 05/16/90"; 20 #endif /* LIBC_SCCS and not lint */ 21 22 #include <stdlib.h> 23 #include <stddef.h> 24 25 /* 26 * getenv -- 27 * Returns ptr to value associated with name, if any, else NULL. 28 */ 29 char * 30 getenv(name) 31 char *name; 32 { 33 int offset; 34 char *_findenv(); 35 36 return(_findenv(name, &offset)); 37 } 38 39 /* 40 * _findenv -- 41 * Returns pointer to value associated with name, if any, else NULL. 42 * Sets offset to be the offset of the name/value combination in the 43 * environmental array, for use by setenv(3) and unsetenv(3). 44 * Explicitly removes '=' in argument name. 45 * 46 * This routine *should* be a static; don't use it. 47 */ 48 char * 49 _findenv(name, offset) 50 register char *name; 51 int *offset; 52 { 53 extern char **environ; 54 register int len; 55 register char **P, *C; 56 57 for (C = name, len = 0; *C && *C != '='; ++C, ++len); 58 for (P = environ; *P; ++P) 59 if (!strncmp(*P, name, len)) 60 if (*(C = *P + len) == '=') { 61 *offset = P - environ; 62 return(++C); 63 } 64 return(NULL); 65 } 66