/* Copyright (C) 1992, 1995, 1996, 1997, 1998 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#if HAVE_CONFIG_H
# include <config.h>
#endif
#include <errno.h>
#if !_LIBC
# if !defined errno && !defined HAVE_ERRNO_DECL
extern int errno;
# endif
# define __set_errno(ev) ((errno) = (ev))
#endif
#if _LIBC || HAVE_STDLIB_H
# include <stdlib.h>
#endif
#if _LIBC || HAVE_STRING_H
# include <string.h>
#endif
#if _LIBC || HAVE_UNISTD_H
# include <unistd.h>
#endif
#if !_LIBC
# define __environ environ
# ifndef HAVE_ENVIRON_DECL
extern char **environ;
# endif
#endif
#if _LIBC
/* This lock protects against simultaneous modifications of `environ'. */
# include <bits/libc-lock.h>
__libc_lock_define_initialized (static, envlock)
# define LOCK __libc_lock_lock (envlock)
# define UNLOCK __libc_lock_unlock (envlock)
#else
# define LOCK
# define UNLOCK
#endif
/* In the GNU C library we must keep the namespace clean. */
#ifdef _LIBC
# define setenv __setenv
# define unsetenv __unsetenv
# define clearenv __clearenv
# define tfind __tfind
# define tsearch __tsearch
#endif
/* In the GNU C library implementation we try to be more clever and
allow arbitrary many changes of the environment given that the used
values are from a small set. Outside glibc this will eat up all
memory after a while. */
#if defined _LIBC || (defined HAVE_SEARCH_H && defined HAVE_TSEARCH \
&& defined __GNUC__)
# define USE_TSEARCH 1
# include <search.h>
/* This is a pointer to the root of the search tree with the known
values. */
static void *known_values;
# define KNOWN_VALUE(Str) \
({ \
void *value = tfind (Str, &known_values, (__compar_fn_t) strcmp); \
value != NULL ? *(char **) value : NULL; \
})
# define STORE_VALUE(Str) \
tsearch (Str, &known_values, (__compar_fn_t) strcmp)
#else
# undef USE_TSEARCH
# define KNOWN_VALUE(Str) NULL
# define STORE_VALUE(Str) do { } while (0)
#endif
/* If this variable is not a null pointer we allocated the current
environment. */
static char **last_environ;
int
setenv (name, value, replace)
const char *name;
const char *value;
int replace;
{
register char **ep;
register size_t size;
const size_t namelen = strlen (name);
const size_t vallen = strlen (value) + 1;
LOCK;
size = 0;
if (__environ != NULL)
{
for (ep = __environ; *ep != NULL; ++ep)
if (!strncmp (*ep, name, namelen) && (*ep)[namelen] == '=')
break;
else
++size;
}
if (__environ == NULL || *ep == NULL)
{
char **new_environ;
#ifdef USE_TSEARCH
char *new_value;
#endif
/* We allocated this space; we can extend it. */
new_environ = (char **) realloc (last_environ,
(size + 2) * sizeof (char *));
if (new_environ == NULL)
{
UNLOCK;
return -1;
}
/* See whether the value is already known. */
#ifdef USE_TSEARCH
new_value = alloca (namelen + 1 + vallen);
# ifdef _LIBC
__mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1),
value, vallen);
# else
memcpy (new_value, name, namelen);
new_value[namelen] = '=';
memcpy (&new_value[namelen + 1], value, vallen);
# endif
new_environ[size] = KNOWN_VALUE (new_value);
if (new_environ[size] == NULL)
#endif
{
new_environ[size] = malloc (namelen + 1 + vallen);
if (new_environ[size] == NULL)
{
__set_errno (ENOMEM);
UNLOCK;
return -1;
}
#ifdef USE_TSEARCH
memcpy (new_environ[size], new_value, namelen + 1 + vallen);
#else
memcpy (new_environ[size], name, namelen);
new_environ[size][namelen] = '=';
memcpy (&new_environ[size][namelen + 1], value, vallen);
#endif
}
if (__environ != last_environ)
memcpy ((char *) new_environ, (char *) __environ,
size * sizeof (char *));
new_environ[size + 1] = NULL;
last_environ = __environ = new_environ;
}
else if (replace)
{
char *new_value;
char *np;
/* The existing string is too short; malloc a new one. */
#ifdef USE_TSEARCH
new_value = alloca (namelen + 1 + vallen);
# ifdef _LIBC
__mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1),
value, vallen);
# else
memcpy (new_value, name, namelen);
new_value[namelen] = '=';
memcpy (&new_value[namelen + 1], value, vallen);
# endif
np = KNOWN_VALUE (new_value);
if (np == NULL)
#endif
{
np = malloc (namelen + 1 + vallen);
if (np == NULL)
{
UNLOCK;
return -1;
}
#ifdef USE_TSEARCH
memcpy (np, new_value, namelen + 1 + vallen);
#else
memcpy (np, name, namelen);
np[namelen] = '=';
memcpy (&np[namelen + 1], value, vallen);
#endif
}
/* Keep the old value around. */
STORE_VALUE (*ep);
*ep = np;
}
UNLOCK;
return 0;
}
void
unsetenv (name)
const char *name;
{
const size_t len = strlen (name);
char **ep;
LOCK;
for (ep = __environ; *ep != NULL; ++ep)
if (!strncmp (*ep, name, len) && (*ep)[len] == '=')
{
/* Found it. Remove this pointer by moving later ones back. */
char **dp = ep;
/* Store the value so that we can reuse it later. */
STORE_VALUE (*ep);
do
dp[0] = dp[1];
while (*dp++);
/* Continue the loop in case NAME appears again. */
}
UNLOCK;
}
/* The `clearenv' was planned to be added to POSIX.1 but probably
never made it. Nevertheless the POSIX.9 standard (POSIX bindings
for Fortran 77) requires this function. */
int
clearenv ()
{
LOCK;
if (__environ == last_environ && __environ != NULL)
{
/* We allocated this environment so we can free it. Store all the
strings. */
char **ep = __environ;
while (*ep != NULL)
STORE_VALUE (*ep++);
free (__environ);
last_environ = NULL;
}
/* Clear the environment pointer removes the whole environment. */
__environ = NULL;
UNLOCK;
return 0;
}
#ifdef _LIBC
# undef setenv
# undef unsetenv
# undef clearenv
weak_alias (__setenv, setenv)
weak_alias (__unsetenv, unsetenv)
weak_alias (__clearenv, clearenv)
#endif