/*
 * Copyright (C) 2014-2023 Firejail Authors
 *
 * This file is part of firejail project
 *
 * 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 2 of the License, 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; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "firejail.h"
#include <fnmatch.h>

#define MAX_READ 4096	// maximum line length
char *restricted_user = NULL;


int restricted_shell(const char *user) {
	EUID_ASSERT();
	assert(user);

	// open profile file:
	char *fname;
	if (asprintf(&fname, "%s/login.users", SYSCONFDIR) == -1)
		errExit("asprintf");
	FILE *fp = fopen(fname, "re");
	free(fname);
	if (fp == NULL)
		return 0;

	int lineno = 0;
	char buf[MAX_READ];
	while (fgets(buf, MAX_READ, fp)) {
		lineno++;

		// remove empty spaces at the beginning of the line
		char *ptr = buf;
		while (*ptr == ' ' || *ptr == '\t') {
			ptr++;
		}
		if (*ptr == '\n' || *ptr == '#')
			continue;

		//
		// parse line
		//

		// extract users
		char *usr = ptr;
		char *args = strchr(usr, ':');
		if (args == NULL) {
			fprintf(stderr, "Error: users.conf line %d\n", lineno);
			exit(1);
		}

		*args = '\0';
		args++;
		ptr = strchr(args, '\n');
		if (ptr)
			*ptr = '\0';

		// extract firejail command line arguments
		char *ptr2 = args;
		int found = 0;
		while (*ptr2 != '\0') {
			if (*ptr2 != ' ' && *ptr2 != '\t') {
				found = 1;
				break;
			}
			ptr2++;
		}
		// if nothing follows, continue
		if (!found)
			continue;

		// user name globbing
		if (fnmatch(usr, user, 0) == 0) {
			// process program arguments

			fullargv[0] = "firejail";
			int i;
			ptr = args;
			for (i = 1; i < MAX_ARGS; i++) {
				// skip blanks
				while (*ptr == ' ' || *ptr == '\t')
					ptr++;
				fullargv[i] = ptr;
#ifdef DEBUG_RESTRICTED_SHELL
				{EUID_ROOT();
				FILE *fp = fopen("/firelog", "ae");
				if (fp) {
					fprintf(fp, "i %d ptr #%s#\n", i, fullargv[i]);
					fclose(fp);
				}
				EUID_USER();}
#endif

				if (*ptr != '\0') {
					// go to the end of the word
					while (*ptr != ' ' && *ptr != '\t' && *ptr != '\0')
						ptr++;
					*ptr ='\0';
					fullargv[i] = strdup(fullargv[i]);
					if (fullargv[i] == NULL)
						errExit("strdup");
					ptr++;
					while (*ptr == ' ' || *ptr == '\t')
						ptr++;
					if (*ptr != '\0')
						continue;
				}
				fullargv[i] = strdup(fullargv[i]);
				fclose(fp);
				return i + 1;
			}
			fprintf(stderr, "Error: too many program arguments in users.conf line %d\n", lineno);
			exit(1);
		}
	}
	fclose(fp);

	return 0;
}
