projects / unix-history / blame
| Commit | Line | Data |
|---|---|---|
| fd08e5b9 KB |
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 this notice is preserved and that due credit is given | |
| 7 | * to the University of California at Berkeley. The name of the University | |
| 8 | * may not be used to endorse or promote products derived from this | |
| 9 | * software without specific prior written permission. This software | |
| 10 | * is provided ``as is'' without express or implied warranty. | |
| 11 | */ | |
| 12 | ||
| 13 | #if defined(LIBC_SCCS) && !defined(lint) | |
| 14 | static char sccsid[] = "@(#)setenv.c 5.1 (Berkeley) %G%"; | |
| 15 | #endif /* LIBC_SCCS and not lint */ | |
| 16 | ||
| 17 | #include <sys/types.h> | |
| 18 | #include <stdio.h> | |
| 19 | ||
| 20 | /* | |
| 21 | * setenv -- | |
| 22 | * Set the value of the environmental variable "name" to be | |
| 23 | * "value". If rewrite is set, replace any current value. | |
| 24 | */ | |
| 25 | setenv(name, value, rewrite) | |
| 26 | register char *name, *value; | |
| 27 | int rewrite; | |
| 28 | { | |
| 29 | extern char **environ; | |
| 30 | static int alloced; /* if allocated space before */ | |
| 31 | register char *C; | |
| 32 | int l_value, offset; | |
| 33 | char *malloc(), *realloc(), *_findenv(); | |
| 34 | ||
| 35 | if (*value == '=') /* no `=' in value */ | |
| 36 | ++value; | |
| 37 | l_value = strlen(value); | |
| 38 | if ((C = _findenv(name, &offset))) { /* find if already exists */ | |
| 39 | if (!rewrite) | |
| 40 | return(0); | |
| 41 | if (strlen(C) >= l_value) { /* old larger; copy over */ | |
| 42 | while (*C++ = *value++); | |
| 43 | return(0); | |
| 44 | } | |
| 45 | } | |
| 46 | else { /* create new slot */ | |
| 47 | register int cnt; | |
| 48 | register char **P; | |
| 49 | ||
| 50 | for (P = environ, cnt = 0; *P; ++P, ++cnt); | |
| 51 | if (alloced) { /* just increase size */ | |
| 52 | environ = (char **)realloc((char *)environ, | |
| 53 | (u_int)(sizeof(char *) * (cnt + 2))); | |
| 54 | if (!environ) | |
| 55 | return(-1); | |
| 56 | } | |
| 57 | else { /* get new space */ | |
| 58 | alloced = 1; /* copy old entries into it */ | |
| 59 | P = (char **)malloc((u_int)(sizeof(char *) * | |
| 60 | (cnt + 2))); | |
| 61 | if (!P) | |
| 62 | return(-1); | |
| 63 | bcopy(environ, P, cnt * sizeof(char *)); | |
| 64 | environ = P; | |
| 65 | } | |
| 66 | environ[cnt + 1] = NULL; | |
| 67 | offset = cnt; | |
| 68 | } | |
| 69 | for (C = name; *C && *C != '='; ++C); /* no `=' in name */ | |
| 70 | if (!(environ[offset] = /* name + `=' + value */ | |
| 71 | malloc((u_int)((int)(C - name) + l_value + 2)))) | |
| 72 | return(-1); | |
| 73 | for (C = environ[offset]; (*C = *name++) && *C != '='; ++C); | |
| 74 | for (*C++ = '='; *C++ = *value++;); | |
| 75 | return(0); | |
| 76 | } | |
| 77 | ||
| 78 | /* | |
| 79 | * unsetenv(name) -- | |
| 80 | * Delete environmental variable "name". | |
| 81 | */ | |
| 82 | void | |
| 83 | unsetenv(name) | |
| 84 | char *name; | |
| 85 | { | |
| 86 | extern char **environ; | |
| 87 | register char **P; | |
| 88 | int offset; | |
| 89 | ||
| 90 | while (_findenv(name, &offset)) /* if set multiple times */ | |
| 91 | for (P = &environ[offset];; ++P) | |
| 92 | if (!(*P = *(P + 1))) | |
| 93 | break; | |
| 94 | } |