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glib2.0/glib/genviron.c

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/* GLIB - Library of useful routines for C programming
* Copyright (C) 1995-1998 Peter Mattis, Spencer Kimball and Josh MacDonald
*
* SPDX-License-Identifier: LGPL-2.1-or-later
*
* This library 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 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
/*
* Modified by the GLib Team and others 1997-2000. See the AUTHORS
* file for a list of people on the GLib Team. See the ChangeLog
* files for a list of changes. These files are distributed with
* GLib at ftp://ftp.gtk.org/pub/gtk/.
*/
#include "config.h"
#include "genviron.h"
#include <stdlib.h>
#include <string.h>
#ifdef HAVE_CRT_EXTERNS_H
#include <crt_externs.h> /* for _NSGetEnviron */
#endif
#ifdef G_OS_WIN32
#include <windows.h>
#endif
#include "glib-private.h"
#include "gmem.h"
#include "gmessages.h"
#include "gstrfuncs.h"
#include "gunicode.h"
#include "gconvert.h"
#include "gquark.h"
#include "gthreadprivate.h"
/* Environ array functions {{{1 */
static gboolean
g_environ_matches (const gchar *env, const gchar *variable, gsize len)
{
#ifdef G_OS_WIN32
/* TODO handle Unicode environment variable names */
/* Like filesystem paths, environment variables are case-insensitive. */
return g_ascii_strncasecmp (env, variable, len) == 0 && env[len] == '=';
#else
return strncmp (env, variable, len) == 0 && env[len] == '=';
#endif
}
static gint
g_environ_find (gchar **envp,
const gchar *variable)
{
gsize len;
gint i;
if (envp == NULL)
return -1;
len = strlen (variable);
for (i = 0; envp[i]; i++)
{
if (g_environ_matches (envp[i], variable, len))
return i;
}
return -1;
}
/**
* g_environ_getenv:
* @envp: (nullable) (array zero-terminated=1) (transfer none) (element-type filename):
* an environment list (eg, as returned from g_get_environ()), or %NULL
* for an empty environment list
* @variable: (type filename): the environment variable to get
*
* Returns the value of the environment variable @variable in the
* provided list @envp.
*
* Returns: (type filename) (nullable): the value of the environment variable, or %NULL if
* the environment variable is not set in @envp. The returned
* string is owned by @envp, and will be freed if @variable is
* set or unset again.
*
* Since: 2.32
*/
const gchar *
g_environ_getenv (gchar **envp,
const gchar *variable)
{
gint index;
g_return_val_if_fail (variable != NULL, NULL);
index = g_environ_find (envp, variable);
if (index != -1)
return envp[index] + strlen (variable) + 1;
else
return NULL;
}
/**
* g_environ_setenv:
* @envp: (nullable) (array zero-terminated=1) (element-type filename) (transfer full):
* an environment list that can be freed using g_strfreev() (e.g., as
* returned from g_get_environ()), or %NULL for an empty
* environment list
* @variable: (type filename): the environment variable to set, must not
* contain '='
* @value: (type filename): the value for to set the variable to
* @overwrite: whether to change the variable if it already exists
*
* Sets the environment variable @variable in the provided list
* @envp to @value.
*
* Returns: (array zero-terminated=1) (element-type filename) (transfer full):
* the updated environment list. Free it using g_strfreev().
*
* Since: 2.32
*/
gchar **
g_environ_setenv (gchar **envp,
const gchar *variable,
const gchar *value,
gboolean overwrite)
{
gint index;
g_return_val_if_fail (variable != NULL, NULL);
g_return_val_if_fail (strchr (variable, '=') == NULL, NULL);
g_return_val_if_fail (value != NULL, NULL);
index = g_environ_find (envp, variable);
if (index != -1)
{
if (overwrite)
{
g_free (envp[index]);
envp[index] = g_strdup_printf ("%s=%s", variable, value);
}
}
else
{
gint length;
length = envp ? g_strv_length (envp) : 0;
envp = g_renew (gchar *, envp, length + 2);
envp[length] = g_strdup_printf ("%s=%s", variable, value);
envp[length + 1] = NULL;
}
return envp;
}
static gchar **
g_environ_unsetenv_internal (gchar **envp,
const gchar *variable,
gboolean free_value)
{
gsize len;
gchar **e, **f;
len = strlen (variable);
/* Note that we remove *all* environment entries for
* the variable name, not just the first.
*/
e = f = envp;
while (*e != NULL)
{
if (!g_environ_matches (*e, variable, len))
{
*f = *e;
f++;
}
else
{
if (free_value)
g_free (*e);
}
e++;
}
*f = NULL;
return envp;
}
/**
* g_environ_unsetenv:
* @envp: (nullable) (array zero-terminated=1) (element-type filename) (transfer full):
* an environment list that can be freed using g_strfreev() (e.g., as
* returned from g_get_environ()), or %NULL for an empty environment list
* @variable: (type filename): the environment variable to remove, must not
* contain '='
*
* Removes the environment variable @variable from the provided
* environment @envp.
*
* Returns: (array zero-terminated=1) (element-type filename) (transfer full):
* the updated environment list. Free it using g_strfreev().
*
* Since: 2.32
*/
gchar **
g_environ_unsetenv (gchar **envp,
const gchar *variable)
{
g_return_val_if_fail (variable != NULL, NULL);
g_return_val_if_fail (strchr (variable, '=') == NULL, NULL);
if (envp == NULL)
return NULL;
return g_environ_unsetenv_internal (envp, variable, TRUE);
}
/* UNIX implementation {{{1 */
#ifndef G_OS_WIN32
/**
* g_getenv:
* @variable: (type filename): the environment variable to get
*
* Returns the value of an environment variable.
*
* On UNIX, the name and value are byte strings which might or might not
* be in some consistent character set and encoding. On Windows, they are
* in UTF-8.
* On Windows, in case the environment variable's value contains
* references to other environment variables, they are expanded.
*
* Returns: (type filename) (nullable): the value of the environment variable, or %NULL if
* the environment variable is not found. The returned string
* may be overwritten by the next call to g_getenv(), g_setenv()
* or g_unsetenv().
*/
const gchar *
g_getenv (const gchar *variable)
{
g_return_val_if_fail (variable != NULL, NULL);
return getenv (variable);
}
/**
* g_setenv:
* @variable: (type filename): the environment variable to set, must not
* contain '='.
* @value: (type filename): the value for to set the variable to.
* @overwrite: whether to change the variable if it already exists.
*
* Sets an environment variable. On UNIX, both the variable's name and
* value can be arbitrary byte strings, except that the variable's name
* cannot contain '='. On Windows, they should be in UTF-8.
*
* Note that on some systems, when variables are overwritten, the memory
* used for the previous variables and its value isn't reclaimed.
*
* You should be mindful of the fact that environment variable handling
* in UNIX is not thread-safe, and your program may crash if one thread
* calls g_setenv() while another thread is calling getenv(). (And note
* that many functions, such as gettext(), call getenv() internally.)
* This function is only safe to use at the very start of your program,
* before creating any other threads (or creating objects that create
* worker threads of their own).
*
* If you need to set up the environment for a child process, you can
* use g_get_environ() to get an environment array, modify that with
* g_environ_setenv() and g_environ_unsetenv(), and then pass that
* array directly to execvpe(), g_spawn_async(), or the like.
*
* Returns: %FALSE if the environment variable couldn't be set.
*
* Since: 2.4
*/
gboolean
g_setenv (const gchar *variable,
const gchar *value,
gboolean overwrite)
{
gint result;
#ifndef HAVE_SETENV
gchar *string;
#endif
g_return_val_if_fail (variable != NULL, FALSE);
g_return_val_if_fail (strchr (variable, '=') == NULL, FALSE);
g_return_val_if_fail (value != NULL, FALSE);
#ifndef G_DISABLE_CHECKS
/* FIXME: This will be upgraded to a g_warning() in a future release of GLib.
* See https://gitlab.gnome.org/GNOME/glib/issues/715 */
if (g_thread_n_created () > 0)
g_debug ("setenv()/putenv() are not thread-safe and should not be used after threads are created");
#endif
#ifdef HAVE_SETENV
result = setenv (variable, value, overwrite);
#else
if (!overwrite && getenv (variable) != NULL)
return TRUE;
/* This results in a leak when you overwrite existing
* settings. It would be fairly easy to fix this by keeping
* our own parallel array or hash table.
*/
string = g_strconcat (variable, "=", value, NULL);
result = putenv (string);
#endif
return result == 0;
}
#ifdef HAVE__NSGETENVIRON
#define environ (*_NSGetEnviron())
#else
/* According to the Single Unix Specification, environ is not
* in any system header, although unistd.h often declares it.
*/
extern char **environ;
#endif
/**
* g_unsetenv:
* @variable: (type filename): the environment variable to remove, must
* not contain '='
*
* Removes an environment variable from the environment.
*
* Note that on some systems, when variables are overwritten, the
* memory used for the previous variables and its value isn't reclaimed.
*
* You should be mindful of the fact that environment variable handling
* in UNIX is not thread-safe, and your program may crash if one thread
* calls g_unsetenv() while another thread is calling getenv(). (And note
* that many functions, such as gettext(), call getenv() internally.) This
* function is only safe to use at the very start of your program, before
* creating any other threads (or creating objects that create worker
* threads of their own).
*
* If you need to set up the environment for a child process, you can
* use g_get_environ() to get an environment array, modify that with
* g_environ_setenv() and g_environ_unsetenv(), and then pass that
* array directly to execvpe(), g_spawn_async(), or the like.
*
* Since: 2.4
*/
void
g_unsetenv (const gchar *variable)
{
g_return_if_fail (variable != NULL);
g_return_if_fail (strchr (variable, '=') == NULL);
#ifndef G_DISABLE_CHECKS
/* FIXME: This will be upgraded to a g_warning() in a future release of GLib.
* See https://gitlab.gnome.org/GNOME/glib/issues/715 */
if (g_thread_n_created () > 0)
g_debug ("unsetenv() is not thread-safe and should not be used after threads are created");
#endif
#ifdef HAVE_UNSETENV
unsetenv (variable);
#else /* !HAVE_UNSETENV */
/* Mess directly with the environ array.
* This seems to be the only portable way to do this.
*/
g_environ_unsetenv_internal (environ, variable, FALSE);
#endif /* !HAVE_UNSETENV */
}
/**
* g_listenv:
*
* Gets the names of all variables set in the environment.
*
* Programs that want to be portable to Windows should typically use
* this function and g_getenv() instead of using the environ array
* from the C library directly. On Windows, the strings in the environ
* array are in system codepage encoding, while in most of the typical
* use cases for environment variables in GLib-using programs you want
* the UTF-8 encoding that this function and g_getenv() provide.
*
* Returns: (array zero-terminated=1) (element-type filename) (transfer full):
* a %NULL-terminated list of strings which must be freed with
* g_strfreev().
*
* Since: 2.8
*/
gchar **
g_listenv (void)
{
gchar **result, *eq;
gint len, i, j;
len = g_strv_length (environ);
result = g_new0 (gchar *, len + 1);
j = 0;
for (i = 0; i < len; i++)
{
eq = strchr (environ[i], '=');
if (eq)
result[j++] = g_strndup (environ[i], eq - environ[i]);
}
result[j] = NULL;
return result;
}
/**
* g_get_environ:
*
* Gets the list of environment variables for the current process.
*
* The list is %NULL terminated and each item in the list is of the
* form 'NAME=VALUE'.
*
* This is equivalent to direct access to the 'environ' global variable,
* except portable.
*
* The return value is freshly allocated and it should be freed with
* g_strfreev() when it is no longer needed.
*
* Returns: (array zero-terminated=1) (element-type filename) (transfer full):
* the list of environment variables
*
* Since: 2.28
*/
gchar **
g_get_environ (void)
{
return g_strdupv (environ);
}
/* Win32 implementation {{{1 */
#else /* G_OS_WIN32 */
const gchar *
g_getenv (const gchar *variable)
{
GQuark quark;
gchar *value;
wchar_t dummy[2], *wname, *wvalue;
DWORD len;
g_return_val_if_fail (variable != NULL, NULL);
g_return_val_if_fail (g_utf8_validate (variable, -1, NULL), NULL);
/* On Windows NT, it is relatively typical that environment
* variables contain references to other environment variables. If
* so, use ExpandEnvironmentStrings(). (In an ideal world, such
* environment variables would be stored in the Registry as
* REG_EXPAND_SZ type values, and would then get automatically
* expanded before a program sees them. But there is broken software
* that stores environment variables as REG_SZ values even if they
* contain references to other environment variables.)
*/
wname = g_utf8_to_utf16 (variable, -1, NULL, NULL, NULL);
len = GetEnvironmentVariableW (wname, dummy, 2);
if (len == 0)
{
g_free (wname);
if (GetLastError () == ERROR_ENVVAR_NOT_FOUND)
return NULL;
quark = g_quark_from_static_string ("");
return g_quark_to_string (quark);
}
else if (len == 1)
len = 2;
wvalue = g_new (wchar_t, len);
if (GetEnvironmentVariableW (wname, wvalue, len) != len - 1)
{
g_free (wname);
g_free (wvalue);
return NULL;
}
if (wcschr (wvalue, L'%') != NULL)
{
wchar_t *tem = wvalue;
len = ExpandEnvironmentStringsW (wvalue, dummy, 2);
if (len > 0)
{
wvalue = g_new (wchar_t, len);
if (ExpandEnvironmentStringsW (tem, wvalue, len) != len)
{
g_free (wvalue);
wvalue = tem;
}
else
g_free (tem);
}
}
value = g_utf16_to_utf8 (wvalue, -1, NULL, NULL, NULL);
g_free (wname);
g_free (wvalue);
quark = g_quark_from_string (value);
g_free (value);
return g_quark_to_string (quark);
}
gboolean
g_setenv (const gchar *variable,
const gchar *value,
gboolean overwrite)
{
gboolean retval;
wchar_t *wname, *wvalue, *wassignment;
gchar *tem;
g_return_val_if_fail (variable != NULL, FALSE);
g_return_val_if_fail (strchr (variable, '=') == NULL, FALSE);
g_return_val_if_fail (value != NULL, FALSE);
g_return_val_if_fail (g_utf8_validate (variable, -1, NULL), FALSE);
g_return_val_if_fail (g_utf8_validate (value, -1, NULL), FALSE);
if (!overwrite && g_getenv (variable) != NULL)
return TRUE;
/* We want to (if possible) set both the environment variable copy
* kept by the C runtime and the one kept by the system.
*
* We can't use only the C runtime's putenv or _wputenv() as that
* won't work for arbitrary Unicode strings in a "non-Unicode" app
* (with main() and not wmain()). In a "main()" app the C runtime
* initializes the C runtime's environment table by converting the
* real (wide char) environment variables to system codepage, thus
* breaking those that aren't representable in the system codepage.
*
* As the C runtime's putenv() will also set the system copy, we do
* the putenv() first, then call SetEnvironmentValueW ourselves.
*/
wname = g_utf8_to_utf16 (variable, -1, NULL, NULL, NULL);
wvalue = g_utf8_to_utf16 (value, -1, NULL, NULL, NULL);
tem = g_strconcat (variable, "=", value, NULL);
wassignment = g_utf8_to_utf16 (tem, -1, NULL, NULL, NULL);
g_free (tem);
_wputenv (wassignment);
g_free (wassignment);
retval = (SetEnvironmentVariableW (wname, wvalue) != 0);
g_free (wname);
g_free (wvalue);
return retval;
}
void
g_unsetenv (const gchar *variable)
{
wchar_t *wname, *wassignment;
gchar *tem;
g_return_if_fail (variable != NULL);
g_return_if_fail (strchr (variable, '=') == NULL);
g_return_if_fail (g_utf8_validate (variable, -1, NULL));
wname = g_utf8_to_utf16 (variable, -1, NULL, NULL, NULL);
tem = g_strconcat (variable, "=", NULL);
wassignment = g_utf8_to_utf16 (tem, -1, NULL, NULL, NULL);
g_free (tem);
_wputenv (wassignment);
g_free (wassignment);
SetEnvironmentVariableW (wname, NULL);
g_free (wname);
}
gchar **
g_listenv (void)
{
gchar **result, *eq;
gint len = 0, j;
wchar_t *p, *q;
p = (wchar_t *) GetEnvironmentStringsW ();
if (p != NULL)
{
q = p;
while (*q)
{
q += wcslen (q) + 1;
len++;
}
}
result = g_new0 (gchar *, len + 1);
j = 0;
q = p;
while (*q)
{
result[j] = g_utf16_to_utf8 (q, -1, NULL, NULL, NULL);
if (result[j] != NULL)
{
eq = strchr (result[j], '=');
if (eq && eq > result[j])
{
*eq = '\0';
j++;
}
else
g_free (result[j]);
}
q += wcslen (q) + 1;
}
result[j] = NULL;
FreeEnvironmentStringsW (p);
return result;
}
gchar **
g_get_environ (void)
{
gunichar2 *strings;
gchar **result;
gint i, n;
strings = GetEnvironmentStringsW ();
for (n = 0, i = 0; strings[n]; i++)
n += wcslen (strings + n) + 1;
result = g_new (char *, i + 1);
for (n = 0, i = 0; strings[n]; i++)
{
result[i] = g_utf16_to_utf8 (strings + n, -1, NULL, NULL, NULL);
n += wcslen (strings + n) + 1;
}
FreeEnvironmentStringsW (strings);
result[i] = NULL;
return result;
}
#endif /* G_OS_WIN32 */
#ifdef G_OS_WIN32
/* Binary compatibility versions. Not for newly compiled code. */
_GLIB_EXTERN const gchar *g_getenv_utf8 (const gchar *variable);
_GLIB_EXTERN gboolean g_setenv_utf8 (const gchar *variable,
const gchar *value,
gboolean overwrite);
_GLIB_EXTERN void g_unsetenv_utf8 (const gchar *variable);
const gchar *
g_getenv_utf8 (const gchar *variable)
{
return g_getenv (variable);
}
gboolean
g_setenv_utf8 (const gchar *variable,
const gchar *value,
gboolean overwrite)
{
return g_setenv (variable, value, overwrite);
}
void
g_unsetenv_utf8 (const gchar *variable)
{
g_unsetenv (variable);
}
#endif
/* Epilogue {{{1 */
/* vim: set foldmethod=marker: */
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