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Annotation of 43BSDTahoe/lib/libc/gen/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 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   5.2 (Berkeley) 6/27/88";
        !            20: #endif /* LIBC_SCCS and not lint */
        !            21: 
        !            22: #include <sys/types.h>
        !            23: #include <stdio.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 *malloc(), *realloc(), *_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:                            (u_int)(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((u_int)(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((u_int)((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: }

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