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/* Copyright (c) 1991
* Juergen Weigert (jnweiger@immd4.informatik.uni-erlangen.de)
* Michael Schroeder (mlschroe@immd4.informatik.uni-erlangen.de)
* Copyright (c) 1987 Oliver Laumann
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 1, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program (see the file COPYING); if not, write to the
* Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* Noteworthy contributors to screen's design and implementation:
* Wayne Davison (davison@borland.com)
* Patrick Wolfe (pat@kai.com, kailand!pat)
* Bart Schaefer (schaefer@cse.ogi.edu)
* Nathan Glasser (nathan@brokaw.lcs.mit.edu)
* Larry W. Virden (lwv27%cas.BITNET@CUNYVM.CUNY.Edu)
* Howard Chu (hyc@hanauma.jpl.nasa.gov)
* Tim MacKenzie (tym@dibbler.cs.monash.edu.au)
* Markku Jarvinen (mta@{cc,cs,ee}.tut.fi)
* Marc Boucher (marc@CAM.ORG)
*
****************************************************************
*/
/*
* putenv -- put value into environment
*
* Usage: i = putenv (string)
* int i;
* char *string;
*
* where string is of the form <name>=<value>.
* If "value" is 0, then "name" will be deleted from the environment.
* Putenv returns 0 normally, -1 on error (not enough core for malloc).
*
* Putenv may need to add a new name into the environment, or to
* associate a value longer than the current value with a particular
* name. So, to make life simpler, putenv() copies your entire
* environment into the heap (i.e. malloc()) from the stack
* (i.e. where it resides when your process is initiated) the first
* time you call it.
*
* HISTORY
* 3-Sep-91 Michael Schroeder (mlschroe). Modified to behave as
* as putenv.
* 16-Aug-91 Tim MacKenzie (tym) at Monash University. Modified for
* use in screen (iScreen) (ignores final int parameter)
* 14-Oct-85 Michael Mauldin (mlm) at Carnegie-Mellon University
* Ripped out of CMU lib for Rob-O-Matic portability
* 20-Nov-79 Steven Shafer (sas) at Carnegie-Mellon University
* Created for VAX. Too bad Bell Labs didn't provide this. It's
* unfortunate that you have to copy the whole environment onto the
* heap, but the bookkeeping-and-not-so-much-copying approach turns
* out to be much hairier. So, I decided to do the simple thing,
* copying the entire environment onto the heap the first time you
* call putenv(), then doing realloc() uniformly later on.
*/
#include "config.h"
#if defined(NEEDSETENV)
#define EXTRASIZE 5 /* increment to add to env. size */
char *index(), *malloc(), *realloc();
int strlen();
static int envsize = -1; /* current size of environment */
extern char **environ; /* the global which is your env. */
static int findenv(); /* look for a name in the env. */
static int newenv(); /* copy env. from stack to heap */
static int moreenv(); /* incr. size of env. */
int unsetenv(name)
char *name;
{
register int i;
i = findenv(name);
if (i<0)
return; /* Already here */
free(environ[i]);
if (envsize > 0)
envsize--;
for (; environ[i]; i++)
environ[i] = environ[i+1];
}
int putenv(string)
char *string;
{
register int i, j;
register char *p;
if (envsize < 0)
{ /* first time putenv called */
if (newenv() < 0) /* copy env. to heap */
return (-1);
}
i = findenv(string); /* look for name in environment */
if (i < 0)
{ /* name must be added */
for (i = 0; environ[i]; i++);
if (i >= (envsize - 1))
{ /* need new slot */
if (moreenv() < 0)
return (-1);
}
p = malloc(strlen(string) + 1);
if (p == 0) /* not enough core */
return (-1);
environ[i + 1] = 0; /* new end of env. */
}
else
{ /* name already in env. */
p = realloc(environ[i], strlen(string) + 1);
if (p == 0)
return (-1);
}
sprintf(p, "%s", string); /* copy into env. */
environ[i] = p;
return (0);
}
static int findenv(name)
char *name;
{
register char *namechar, *envchar;
register int i, found;
found = 0;
for (i = 0; environ[i] && !found; i++)
{
envchar = environ[i];
namechar = name;
while (*namechar && *namechar != '=' && (*namechar == *envchar))
{
namechar++;
envchar++;
}
found = ((*namechar == '\0' || *namechar == '=') && *envchar == '=');
}
return (found ? i - 1 : -1);
}
static int newenv()
{
register char **env, *elem;
register int i, esize;
for (i = 0; environ[i]; i++)
;
esize = i + EXTRASIZE + 1;
env = (char **)malloc(esize * sizeof (elem));
if (env == 0)
return (-1);
for (i = 0; environ[i]; i++)
{
elem = malloc(strlen(environ[i]) + 1);
if (elem == 0)
return (-1);
env[i] = elem;
strcpy(elem, environ[i]);
}
env[i] = 0;
environ = env;
envsize = esize;
return (0);
}
static int moreenv()
{
register int esize;
register char **env;
esize = envsize + EXTRASIZE;
env = (char **)realloc(environ, esize * sizeof (*env));
if (env == 0)
return (-1);
environ = env;
envsize = esize;
return (0);
}
#endif /* NEEDSETENV */
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