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Annotation of 43BSDReno/lib/libc/stdlib/setenv.c, revision 1.1

1.1     ! root        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: (1) source distributions retain this entire copyright
        !             7:  * notice and comment, and (2) distributions including binaries display
        !             8:  * the following acknowledgement:  ``This product includes software
        !             9:  * developed by the University of California, Berkeley and its contributors''
        !            10:  * in the documentation or other materials provided with the distribution
        !            11:  * and in all advertising materials mentioning features or use of this
        !            12:  * software. Neither the name of the University nor the names of its
        !            13:  * contributors may be used to endorse or promote products derived
        !            14:  * from this software without specific prior written permission.
        !            15:  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
        !            16:  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
        !            17:  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
        !            18:  */
        !            19: 
        !            20: #if defined(LIBC_SCCS) && !defined(lint)
        !            21: static char sccsid[] = "@(#)setenv.c   5.4 (Berkeley) 6/1/90";
        !            22: #endif /* LIBC_SCCS and not lint */
        !            23: 
        !            24: #include <stddef.h>
        !            25: #include <stdlib.h>
        !            26: 
        !            27: /*
        !            28:  * setenv --
        !            29:  *     Set the value of the environmental variable "name" to be
        !            30:  *     "value".  If rewrite is set, replace any current value.
        !            31:  */
        !            32: setenv(name, value, rewrite)
        !            33:        register char *name, *value;
        !            34:        int rewrite;
        !            35: {
        !            36:        extern char **environ;
        !            37:        static int alloced;                     /* if allocated space before */
        !            38:        register char *C;
        !            39:        int l_value, offset;
        !            40:        char *_findenv();
        !            41: 
        !            42:        if (*value == '=')                      /* no `=' in value */
        !            43:                ++value;
        !            44:        l_value = strlen(value);
        !            45:        if ((C = _findenv(name, &offset))) {    /* find if already exists */
        !            46:                if (!rewrite)
        !            47:                        return(0);
        !            48:                if (strlen(C) >= l_value) {     /* old larger; copy over */
        !            49:                        while (*C++ = *value++);
        !            50:                        return(0);
        !            51:                }
        !            52:        }
        !            53:        else {                                  /* create new slot */
        !            54:                register int    cnt;
        !            55:                register char   **P;
        !            56: 
        !            57:                for (P = environ, cnt = 0; *P; ++P, ++cnt);
        !            58:                if (alloced) {                  /* just increase size */
        !            59:                        environ = (char **)realloc((char *)environ,
        !            60:                            (size_t)(sizeof(char *) * (cnt + 2)));
        !            61:                        if (!environ)
        !            62:                                return(-1);
        !            63:                }
        !            64:                else {                          /* get new space */
        !            65:                        alloced = 1;            /* copy old entries into it */
        !            66:                        P = (char **)malloc((size_t)(sizeof(char *) *
        !            67:                            (cnt + 2)));
        !            68:                        if (!P)
        !            69:                                return(-1);
        !            70:                        bcopy(environ, P, cnt * sizeof(char *));
        !            71:                        environ = P;
        !            72:                }
        !            73:                environ[cnt + 1] = NULL;
        !            74:                offset = cnt;
        !            75:        }
        !            76:        for (C = name; *C && *C != '='; ++C);   /* no `=' in name */
        !            77:        if (!(environ[offset] =                 /* name + `=' + value */
        !            78:            malloc((size_t)((int)(C - name) + l_value + 2))))
        !            79:                return(-1);
        !            80:        for (C = environ[offset]; (*C = *name++) && *C != '='; ++C);
        !            81:        for (*C++ = '='; *C++ = *value++;);
        !            82:        return(0);
        !            83: }
        !            84: 
        !            85: /*
        !            86:  * unsetenv(name) --
        !            87:  *     Delete environmental variable "name".
        !            88:  */
        !            89: void
        !            90: unsetenv(name)
        !            91:        char    *name;
        !            92: {
        !            93:        extern char **environ;
        !            94:        register char **P;
        !            95:        int offset;
        !            96: 
        !            97:        while (_findenv(name, &offset))         /* if set multiple times */
        !            98:                for (P = &environ[offset];; ++P)
        !            99:                        if (!(*P = *(P + 1)))
        !           100:                                break;
        !           101: }

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