/*
 * Copyright (C) 1997, 1998, 1999, 2000 Free Software Foundation
 * Copyright (C) 1999, 2000 Red Hat, Inc.
 * All rights reserved.
 *
 * This file is part of the Mate Library.
 *
 * The Mate 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 Mate 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 Mate Library; see the file COPYING.LIB.  If not,
 * write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */
/*
  @NOTATION@
 */

/*
 *
 * Mate utility routines.
 * (C)  1997, 1998, 1999 the Free Software Foundation.
 *
 * Author: Miguel de Icaza,
 */
#include <config.h>

/* needed for S_ISLNK with 'gcc -ansi -pedantic' on GNU/Linux */
#ifndef _BSD_SOURCE
#  define _BSD_SOURCE 1
#endif

#include <sys/types.h>

#include <errno.h>
#include <stdarg.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <glib.h>

#ifndef G_OS_WIN32
	#include <pwd.h>
#endif

#include <limits.h>
#include "mate-program.h"
#include "mate-util.h"

#ifdef G_OS_WIN32
	#include <windows.h>
#endif

#if defined(__APPLE__) && defined(HAVE_NSGETENVIRON) && defined(HAVE_CRT_EXTERNS_H)
	#include <crt_externs.h>
	#define environ (*_NSGetEnviron())
#endif

/**
 * mate_util_user_shell:
 *
 * Retrieves the user's preferred shell.
 *
 * Returns: A newly allocated string that is the path to the shell.
 */
char* mate_util_user_shell(void)
{
	#ifndef G_OS_WIN32
		struct passwd* pw;
		int i;
		const char* shell;
		const char shells[][14] = {
			/* Note that on some systems shells can also
			 * be installed in /usr/bin */
			"/bin/bash", "/usr/bin/bash",
			"/bin/zsh", "/usr/bin/zsh",
			"/bin/tcsh", "/usr/bin/tcsh",
			"/bin/ksh", "/usr/bin/ksh",
			"/bin/csh", "/bin/sh"
		};

		if (geteuid() == getuid() && getegid() == getgid())
		{
			/* only in non-setuid */
			if ((shell = g_getenv("SHELL")))
			{
				if (access(shell, X_OK) == 0)
				{
					return g_strdup(shell);
				}
			}
		}

		pw = getpwuid(getuid());

		if (pw && pw->pw_shell)
		{
			if (access(pw->pw_shell, X_OK) == 0)
			{
				return g_strdup(pw->pw_shell);
			}
		}

		for (i = 0; i != G_N_ELEMENTS(shells); i++)
		{
			if (access(shells [i], X_OK) == 0)
			{
				return g_strdup(shells[i]);
			}
		}

		/* If /bin/sh doesn't exist, your system is truly broken.  */
		abort();

		/* Placate compiler.  */
		return NULL;
	#else
		/* g_find_program_in_path() always looks also in the Windows
		 * and System32 directories, so it should always find either cmd.exe
		 * or command.com.
		 */
		char* retval = g_find_program_in_path("cmd.exe");

		if (retval == NULL)
			retval = g_find_program_in_path("command.com");

		g_assert(retval != NULL);

		return retval;
	#endif
}

/**
 * g_extension_pointer:
 * @path: A filename or file path.
 *
 * Extracts the extension from the end of a filename (the part after the final
 * '.' in the filename).
 *
 * Returns: A pointer to the extension part of the filename, or a
 * pointer to the end of the string if the filename does not
 * have an extension.
 */
const char* g_extension_pointer(const char* path)
{
	char* s, *t;

	g_return_val_if_fail(path != NULL, NULL);

	/* get the dot in the last element of the path */
	t = strrchr(path, G_DIR_SEPARATOR);

	if (t != NULL)
	{
		s = strrchr(t, '.');
	}
	else
	{
		s = strrchr(path, '.');
	}

	if (s == NULL)
	{
		return path + strlen(path); /* There is no extension. */
	}
	else
	{
		++s;      /* pass the . */
		return s;
	}
}

/**
 * mate_setenv:
 * @name: An environment variable name.
 * @value: The value to assign to the environment variable.
 * @overwrite: If %TRUE, overwrite the existing @name variable in the
 * environment.
 *
 * Adds "@name=@value" to the environment. Note that on systems without setenv,
 * this leaks memory so please do not use inside a loop or anything like that.
 * The semantics are the same as the glibc setenv() (if setenv() exists, it is
 * used).
 *
 * If @overwrite is %FALSE and the variable already exists in the environment,
 * then %0 is returned and the value is not changed.
 *
 * Returns: %0 on success, %-1 on error
 *
 * @Deprecated: 2.30: Use g_setenv() instead
 **/
int mate_setenv(const char*name, const char* value, gboolean overwrite)
{
	#if defined(HAVE_SETENV)
		return setenv(name, value != NULL ? value : "", overwrite);
	#else
		char* string;

		if (!overwrite && g_getenv(name) != NULL)
		{
			return 0;
		}

		/* 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(name, "=", value, NULL);
		return putenv(string);
	#endif
}

/**
 * mate_unsetenv:
 * @name: The environment variable to unset.
 *
 * Description: Removes @name from the environment.
 * In case there is no native implementation of unsetenv,
 * this could cause leaks depending on the implementation of
 * environment.
 *
 * @Deprecated: 2.30: Use g_unsetenv() instead
 **/
void mate_unsetenv(const char* name)
{
	#if defined(HAVE_UNSETENV)
		unsetenv(name);
	#else
		extern char** environ;
		int i, len;

		len = strlen(name);

		/* Mess directly with the environ array.
		 * This seems to be the only portable way to do this.
		 */
		for (i = 0; environ[i] != NULL; i++)
		{
			if (strncmp(environ[i], name, len) == 0 && environ[i][len + 1] == '=')
			{
				break;
			}
		}

		while (environ[i] != NULL)
		{
			environ[i] = environ[i + 1];
			i++;
		}
	#endif
}

/**
 * mate_clearenv:
 *
 * Description: Clears out the environment completely.
 * In case there is no native implementation of clearenv,
 * this could cause leaks depending on the implementation
 * of environment.
 *
 * @Deprecated: 2.30
 **/
void mate_clearenv(void)
{
	#ifdef HAVE_CLEARENV
		clearenv();
	#else
		extern char** environ;
		environ[0] = NULL;
	#endif
}

/* Deprecated: */
/**
 * mate_is_program_in_path:
 * @program: A program name.
 *
 * Deprecated, use #g_find_program_in_path
 *
 * Returns: %NULL if program is not on the path or a string
 * allocated with g_malloc() with the full path name of the program
 * found.
 */