155 lines
3.8 KiB
C
155 lines
3.8 KiB
C
/* Copyright (C) 1992, 1995-2002, 2005-2025 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
|
|
This file is free software: you can redistribute it and/or modify
|
|
it under the terms of the GNU Lesser General Public License as
|
|
published by the Free Software Foundation; either version 2.1 of the
|
|
License, or (at your option) any later version.
|
|
|
|
This file 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 Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public License
|
|
along with this program. If not, see <https://www.gnu.org/licenses/>. */
|
|
|
|
/* Don't use __attribute__ __nonnull__ in this compilation unit. Otherwise gcc
|
|
optimizes away the name == NULL test below. */
|
|
#define _GL_ARG_NONNULL(params)
|
|
|
|
#include <config.h>
|
|
|
|
/* Specification. */
|
|
#include <stdlib.h>
|
|
|
|
#include <errno.h>
|
|
#if !_LIBC
|
|
# define __set_errno(ev) ((errno) = (ev))
|
|
#endif
|
|
|
|
#include <string.h>
|
|
#include <unistd.h>
|
|
|
|
#if !_LIBC
|
|
# define __environ environ
|
|
#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 unsetenv __unsetenv
|
|
#endif
|
|
|
|
#if _LIBC || !HAVE_UNSETENV
|
|
|
|
int
|
|
unsetenv (const char *name)
|
|
{
|
|
size_t len;
|
|
|
|
if (name == NULL || *name == '\0' || strchr (name, '=') != NULL)
|
|
{
|
|
__set_errno (EINVAL);
|
|
return -1;
|
|
}
|
|
|
|
len = strlen (name);
|
|
|
|
#if HAVE_DECL__PUTENV /* native Windows */
|
|
/* The Microsoft documentation
|
|
<https://learn.microsoft.com/en-us/cpp/c-runtime-library/reference/putenv-wputenv>
|
|
says:
|
|
"Don't change an environment entry directly: instead,
|
|
use _putenv or _wputenv to change it."
|
|
Note: Microsoft's _putenv updates not only the contents of _environ but
|
|
also the contents of _wenviron, so that both are in kept in sync.
|
|
|
|
The way to remove an environment variable is to pass to _putenv a string
|
|
of the form "NAME=". (NB: This is a different convention than with glibc
|
|
putenv, which expects a string of the form "NAME"!) */
|
|
{
|
|
int putenv_result;
|
|
char *name_ = malloc (len + 2);
|
|
if (name_ == NULL)
|
|
return -1;
|
|
memcpy (name_, name, len);
|
|
name_[len] = '=';
|
|
name_[len + 1] = 0;
|
|
putenv_result = _putenv (name_);
|
|
/* In this particular case it is OK to free() the argument passed to
|
|
_putenv. */
|
|
free (name_);
|
|
return putenv_result;
|
|
}
|
|
#else
|
|
|
|
LOCK;
|
|
|
|
char **ep = __environ;
|
|
while (*ep != NULL)
|
|
if (!strncmp (*ep, name, len) && (*ep)[len] == '=')
|
|
{
|
|
/* Found it. Remove this pointer by moving later ones back. */
|
|
char **dp = ep;
|
|
|
|
do
|
|
dp[0] = dp[1];
|
|
while (*dp++);
|
|
/* Continue the loop in case NAME appears again. */
|
|
}
|
|
else
|
|
++ep;
|
|
|
|
UNLOCK;
|
|
|
|
return 0;
|
|
#endif
|
|
}
|
|
|
|
#ifdef _LIBC
|
|
# undef unsetenv
|
|
weak_alias (__unsetenv, unsetenv)
|
|
#endif
|
|
|
|
#else /* HAVE_UNSETENV */
|
|
|
|
# undef unsetenv
|
|
# if !HAVE_DECL_UNSETENV
|
|
# if VOID_UNSETENV
|
|
extern void unsetenv (const char *);
|
|
# else
|
|
extern int unsetenv (const char *);
|
|
# endif
|
|
# endif
|
|
|
|
/* Call the underlying unsetenv, in case there is hidden bookkeeping
|
|
that needs updating beyond just modifying environ. */
|
|
int
|
|
rpl_unsetenv (const char *name)
|
|
{
|
|
int result = 0;
|
|
if (!name || !*name || strchr (name, '='))
|
|
{
|
|
errno = EINVAL;
|
|
return -1;
|
|
}
|
|
while (getenv (name))
|
|
# if !VOID_UNSETENV
|
|
result =
|
|
# endif
|
|
unsetenv (name);
|
|
return result;
|
|
}
|
|
|
|
#endif /* HAVE_UNSETENV */
|