/**
 * Copyright (C) 2007 International Business Machines
 * Author(s): Michael Halcrow <mhalcrow@us.ibm.com>
 *            Dustin Kirkland <kirkland@ubuntu.com>
 *
 * 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., 59 Temple Place - Suite 330, Boston, MA
 * 02111-1307, USA.
 */

#include <stdio.h>
#include <ecryptfs.h>
#include <string.h>

void usage(void)
{
	printf("Usage:\n"
	       "\n"
	       "ecryptfs-unwrap-passphrase [file]\n"
	       "or\n"
	       "printf \"%%s\" \"wrapping passphrase\" | "
	       "ecryptfs-unwrap-passphrase [file] -\n"
	       "\n");
}

int main(int argc, char *argv[])
{
	char *file;
	char passphrase[ECRYPTFS_MAX_PASSWORD_LENGTH + 1];
	char *wrapping_passphrase;
	char salt[ECRYPTFS_SALT_SIZE];
	char salt_hex[ECRYPTFS_SALT_SIZE_HEX];
	int rc = 0;

	if (argc == 1) {
		/* interactive, and try default wrapped-passphrase file */
		file = ecryptfs_get_wrapped_passphrase_filename();
		if (file == NULL) {
			usage();
			goto out;
		}
		wrapping_passphrase = ecryptfs_get_passphrase("Passphrase");
	} else if (argc == 2) {
		/* interactive mode */
		file = argv[1];
		wrapping_passphrase = ecryptfs_get_passphrase("Passphrase");
	} else if (argc == 3 &&
		   strlen(argv[2]) == 1 && strncmp(argv[2], "-", 1) == 0) {
		/* stdin mode */
		file = argv[1];
		wrapping_passphrase = ecryptfs_get_passphrase(NULL);
	} else if (argc == 3 &&
		   (strlen(argv[2]) != 1 || strncmp(argv[2], "-", 1) == 0)) {
		/* argument mode */
		file = argv[1];
		wrapping_passphrase = argv[2];
	} else {
		usage();
		goto out;
	}
	if (wrapping_passphrase == NULL ||
	    strlen(wrapping_passphrase) > ECRYPTFS_MAX_PASSWORD_LENGTH) {
		usage();
		goto out;
	}

	rc = ecryptfs_read_salt_hex_from_rc(salt_hex);
	if (rc) {
		from_hex(salt, ECRYPTFS_DEFAULT_SALT_HEX, ECRYPTFS_SALT_SIZE);
	} else
		from_hex(salt, salt_hex, ECRYPTFS_SALT_SIZE);
	if ((rc = ecryptfs_unwrap_passphrase(passphrase, file,
					     wrapping_passphrase, salt))) {
		fprintf(stderr, "%s [%d]\n", ECRYPTFS_ERROR_UNWRAP, rc);
		fprintf(stderr, "%s\n", ECRYPTFS_INFO_CHECK_LOG);
		rc = 1;
		goto out;
	}
	printf("%s\n", passphrase);
out:
	return rc;
}
