earlybrowserreborn - Rev 1

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/*
 * Copyright (c) 1987 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that: (1) source distributions retain this entire copyright
 * notice and comment, and (2) distributions including binaries display
 * the following acknowledgement:  ``This product includes software
 * developed by the University of California, Berkeley and its contributors''
 * in the documentation or other materials provided with the distribution
 * and in all advertising materials mentioning features or use of this
 * software. Neither the name of the University nor the names of its
 * contributors may be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */


#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)setenv.c    5.4 (Berkeley) 6/1/90";
#endif /* LIBC_SCCS and not lint */

#include <stdio.h>
#include <sys/types.h>
extern char *malloc();

/*
 * setenv --
 *      Set the value of the environmental variable "name" to be
 *      "value".  If rewrite is set, replace any current value.
 */

setenv(name, value, rewrite)
        register char *name, *value;
        int rewrite;
{
        extern char **environ;
        static int alloced;                     /* if allocated space before */
        register char *C;
        int l_value, offset;
        char *_findenv();

        if (*value == '=')                      /* no `=' in value */
                ++value;
        l_value = strlen(value);
        if ((C = _findenv(name, &offset))) {    /* find if already exists */
                if (!rewrite)
                        return(0);
                if (strlen(C) >= l_value) {     /* old larger; copy over */
                        while (*C++ = *value++);
                        return(0);
                }
        }
        else {                                  /* create new slot */
                register int    cnt;
                register char   **P;

                for (P = environ, cnt = 0; *P; ++P, ++cnt);
                if (alloced) {                  /* just increase size */
                        environ = (char **)realloc((char *)environ,
                            (size_t)(sizeof(char *) * (cnt + 2)));
                        if (!environ)
                                return(-1);
                }
                else {                          /* get new space */
                        alloced = 1;            /* copy old entries into it */
                        P = (char **)malloc((size_t)(sizeof(char *) *
                            (cnt + 2)));
                        if (!P)
                                return(-1);
                        memcpy(P, environ, cnt * sizeof(char *));
                        environ = P;
                }
                environ[cnt + 1] = NULL;
                offset = cnt;
        }
        for (C = name; *C && *C != '='; ++C);   /* no `=' in name */
        if (!(environ[offset] =                 /* name + `=' + value */
            malloc((size_t)((int)(C - name) + l_value + 2))))
                return(-1);
        for (C = environ[offset]; (*C = *name++) && *C != '='; ++C);
        for (*C++ = '='; *C++ = *value++;);
        return(0);
}

/*
 * unsetenv(name) --
 *      Delete environmental variable "name".
 */

void
unsetenv(name)
        char    *name;
{
        extern char **environ;
        register char **P;
        int offset;

        while (_findenv(name, &offset))         /* if set multiple times */
                for (P = &environ[offset];; ++P)
                        if (!(*P = *(P + 1)))
                                break;
}