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Annotation of 43BSDReno/lib/libc/stdlib/setenv.c, revision 1.1.1.1

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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