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[] = "@(#)setenv.c 5.3 (Berkeley) 05/16/90"; 20 #endif /* LIBC_SCCS and not lint */ 21 22 #include <stddef.h> 23 #include <stdlib.h> 24 25 /* 26 * setenv -- 27 * Set the value of the environmental variable "name" to be 28 * "value". If rewrite is set, replace any current value. 29 */ 30 setenv(name, value, rewrite) 31 register char *name, *value; 32 int rewrite; 33 { 34 extern char **environ; 35 static int alloced; /* if allocated space before */ 36 register char *C; 37 int l_value, offset; 38 char *_findenv(); 39 40 if (*value == '=') /* no `=' in value */ 41 ++value; 42 l_value = strlen(value); 43 if ((C = _findenv(name, &offset))) { /* find if already exists */ 44 if (!rewrite) 45 return(0); 46 if (strlen(C) >= l_value) { /* old larger; copy over */ 47 while (*C++ = *value++); 48 return(0); 49 } 50 } 51 else { /* create new slot */ 52 register int cnt; 53 register char **P; 54 55 for (P = environ, cnt = 0; *P; ++P, ++cnt); 56 if (alloced) { /* just increase size */ 57 environ = (char **)realloc((char *)environ, 58 (size_t)(sizeof(char *) * (cnt + 2))); 59 if (!environ) 60 return(-1); 61 } 62 else { /* get new space */ 63 alloced = 1; /* copy old entries into it */ 64 P = (char **)malloc((size_t)(sizeof(char *) * 65 (cnt + 2))); 66 if (!P) 67 return(-1); 68 bcopy(environ, P, cnt * sizeof(char *)); 69 environ = P; 70 } 71 environ[cnt + 1] = NULL; 72 offset = cnt; 73 } 74 for (C = name; *C && *C != '='; ++C); /* no `=' in name */ 75 if (!(environ[offset] = /* name + `=' + value */ 76 malloc((size_t)((int)(C - name) + l_value + 2)))) 77 return(-1); 78 for (C = environ[offset]; (*C = *name++) && *C != '='; ++C); 79 for (*C++ = '='; *C++ = *value++;); 80 return(0); 81 } 82 83 /* 84 * unsetenv(name) -- 85 * Delete environmental variable "name". 86 */ 87 void 88 unsetenv(name) 89 char *name; 90 { 91 extern char **environ; 92 register char **P; 93 int offset; 94 95 while (_findenv(name, &offset)) /* if set multiple times */ 96 for (P = &environ[offset];; ++P) 97 if (!(*P = *(P + 1))) 98 break; 99 } 100