/*

 * Copyright (C) 2005-2012 Free Software Foundation, Inc.

 *

 * This file is part of GnuTLS.

 *

 * GnuTLS 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 3 of the License, or

 * (at your option) any later version.

 *

 * GnuTLS 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, see

 * <https://www.gnu.org/licenses/>.

 */

#include <config.h>

/* Gnulib portability files. */

#ifndef ENABLE_PSK

#include <stdio.h>

int main(int argc, char **argv)

{

	printf("\nPSK not supported. This program is a dummy.\n\n");

	return 1;

};

#else

#include <stdio.h>

#include <string.h>

#include <stdlib.h>

#include <gnutls/gnutls.h>

#include <psktool-args.h>

#include <gnutls/crypto.h>	/* for random */

#include <sys/types.h>

#include <sys/stat.h>

#ifndef _WIN32

#include <pwd.h>

#include <unistd.h>

#else

#include <windows.h>

#endif

/* Gnulib portability files. */

#include <minmax.h>

#include "getpass.h"

static int write_key(const char *username, const char *key, int key_size,

		     const char *passwd_file);

#define MAX_KEY_SIZE 512

int main(int argc, char **argv)

{

	int ret;

#ifndef _WIN32

	struct passwd *pwd;

#endif

	unsigned char key[MAX_KEY_SIZE];

	char hex_key[MAX_KEY_SIZE * 2 + 1];

	int key_size;

	gnutls_datum_t dkey;

	const char *passwd, *username;

	size_t hex_key_size = sizeof(hex_key);

	if ((ret = gnutls_global_init()) < 0) {

		fprintf(stderr, "global_init: %s\n", gnutls_strerror(ret));

		exit(1);

	}

	umask(066);

	optionProcess(&psktoolOptions, argc, argv);

	if (!HAVE_OPT(PSKFILE)) {

		fprintf(stderr, "You need to specify a PSK key file\n");

		exit(1);

	} else

		passwd = OPT_ARG(PSKFILE);

	if (!HAVE_OPT(USERNAME)) {

#ifndef _WIN32

		pwd = getpwuid(getuid());

		if (pwd == NULL) {

			fprintf(stderr, "No such user\n");

			return -1;

		}

		username = pwd->pw_name;

#else

		fprintf(stderr, "Please specify a user\n");

		return -1;

#endif

	} else

		username = OPT_ARG(USERNAME);

	if (HAVE_OPT(KEYSIZE) && OPT_VALUE_KEYSIZE > MAX_KEY_SIZE) {

		fprintf(stderr, "Key size is too long\n");

		exit(1);

	}

	if (!HAVE_OPT(KEYSIZE) || OPT_VALUE_KEYSIZE < 1)

		key_size = 32;

	else

		key_size = OPT_VALUE_KEYSIZE;

	printf("Generating a random key for user '%s'\n", username);

	ret = gnutls_rnd(GNUTLS_RND_RANDOM, (char *) key, key_size);

	if (ret < 0) {

		fprintf(stderr, "Not enough randomness\n");

		exit(1);

	}

	dkey.data = key;

	dkey.size = key_size;

	ret = gnutls_hex_encode(&dkey, hex_key, &hex_key_size);

	if (ret < 0) {

		fprintf(stderr, "HEX encoding error\n");

		exit(1);

	}

	ret = write_key(username, hex_key, hex_key_size, passwd);

	if (ret == 0)

		printf("Key stored to %s\n", passwd);

	return ret;

}

static int filecopy(const char *src, const char *dst)

{

	FILE *fp, *fp2;

	char line[5 * 1024];

	char *p;

	fp = fopen(dst, "w");

	if (fp == NULL) {

		fprintf(stderr, "Cannot open '%s' for write\n", dst);

		return -1;

	}

	fp2 = fopen(src, "r");

	if (fp2 == NULL) {

		/* empty file */

		fclose(fp);

		return 0;

	}

	line[sizeof(line) - 1] = 0;

	do {

		p = fgets(line, sizeof(line) - 1, fp2);

		if (p == NULL)

			break;

		fputs(line, fp);

	}

	while (1);

	fclose(fp);

	fclose(fp2);

	return 0;

}

static int

write_key(const char *username, const char *key, int key_size,

	  const char *passwd_file)

{

	FILE *fp;

	char line[5 * 1024];

	char *p, *pp;

	char tmpname[1024];

	/* delete previous entry */

	struct stat st;

	FILE *fp2;

	int put;

	if (strlen(passwd_file) + 5 > sizeof(tmpname)) {

		fprintf(stderr, "file '%s' is tooooo long\n", passwd_file);

		return -1;

	}

	snprintf(tmpname, sizeof(tmpname), "%s.tmp", passwd_file);

	if (stat(tmpname, &st) != -1) {

		fprintf(stderr, "file '%s' is locked\n", tmpname);

		return -1;

	}

	if (filecopy(passwd_file, tmpname) != 0) {

		fprintf(stderr, "Cannot copy '%s' to '%s'\n", passwd_file,

			tmpname);

		return -1;

	}

	fp = fopen(passwd_file, "w");

	if (fp == NULL) {

		fprintf(stderr, "Cannot open '%s' for write\n",

			passwd_file);

		(void)remove(tmpname);

		return -1;

	}

	fp2 = fopen(tmpname, "r");

	if (fp2 == NULL) {

		fprintf(stderr, "Cannot open '%s' for read\n", tmpname);

		(void)remove(tmpname);

		fclose(fp);

		return -1;

	}

	put = 0;

	do {

		p = fgets(line, sizeof(line) - 1, fp2);

		if (p == NULL)

			break;

		pp = strchr(line, ':');

		if (pp == NULL)

			continue;

		if (strncmp(p, username,

			    MAX(strlen(username),

				(unsigned int) (pp - p))) == 0) {

			put = 1;

			fprintf(fp, "%s:%s\n", username, key);

		} else {

			fputs(line, fp);

		}

	}

	while (1);

	if (put == 0) {

		fprintf(fp, "%s:%s\n", username, key);

	}

	fclose(fp);

	fclose(fp2);

	(void)remove(tmpname);

	return 0;

}

#endif				/* ENABLE_PSK */