futility/file_type.c

/*
 * Copyright 2015 The Chromium OS Authors. All rights reserved.
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include <errno.h>
#include <fcntl.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>

#include "file_type.h"
#include "futility.h"
#include "gbb_header.h"

/* Human-readable strings */
static const char * const type_strings[] = {
	"unknown",
	"VbPublicKey",
	"VbKeyBlock",
	"VbFirmwarePreamble",
	"GBB",
	"Chrome OS BIOS image",
	"Cr-48 Chrome OS BIOS image",
	"VbKernelPreamble",
	"raw firmware",
	"raw kernel",
	"chromiumos disk image",
	"VbPrivateKey",
};
BUILD_ASSERT(ARRAY_SIZE(type_strings) == NUM_FILE_TYPES);

const char * const futil_file_type_str(enum futil_file_type type)
{
	if ((int) type < 0 || type >= NUM_FILE_TYPES)
		type = FILE_TYPE_UNKNOWN;

	return type_strings[type];
}

/* Try these in order so we recognize the larger objects first */
enum futil_file_type (*recognizers[])(uint8_t *buf, uint32_t len) = {
	&recognize_gpt,
	&recognize_bios_image,
	&recognize_gbb,
	&recognize_vblock1,
	&recognize_privkey,
};

/* Try to figure out what we're looking at */
enum futil_file_type futil_file_type_buf(uint8_t *buf, uint32_t len)
{
	enum futil_file_type type;
	int i;

	for (i = 0; i < ARRAY_SIZE(recognizers); i++) {
		type = recognizers[i](buf, len);
		if (type != FILE_TYPE_UNKNOWN)
			return type;
	}

	return FILE_TYPE_UNKNOWN;
}

enum futil_file_err futil_file_type(const char *filename,
				    enum futil_file_type *type)
{
	int ifd;
	uint8_t *buf;
	uint32_t buf_len;
	struct stat sb;
	enum futil_file_err err = FILE_ERR_NONE;

	*type = FILE_TYPE_UNKNOWN;

	ifd = open(filename, O_RDONLY);
	if (ifd < 0) {
		fprintf(stderr, "Can't open %s: %s\n",
			filename, strerror(errno));
		return FILE_ERR_OPEN;
	}

	if (0 != fstat(ifd, &sb)) {
		fprintf(stderr, "Can't stat input file: %s\n",
			strerror(errno));
		return FILE_ERR_STAT;
	}

	if (S_ISREG(sb.st_mode) || S_ISBLK(sb.st_mode)) {
		err = futil_map_file(ifd, MAP_RO, &buf, &buf_len);
		if (err) {
			close(ifd);
			return err;
		}

		*type = futil_file_type_buf(buf, buf_len);

		err = futil_unmap_file(ifd, MAP_RO, buf, buf_len);
		if (err) {
			close(ifd);
			return err;
		}
	} else if (S_ISDIR(sb.st_mode)) {
		err = FILE_ERR_DIR;
	} else if (S_ISCHR(sb.st_mode)) {
		err = FILE_ERR_CHR;
	} else if (S_ISFIFO(sb.st_mode)) {
		err = FILE_ERR_FIFO;
	} else if (S_ISSOCK(sb.st_mode)) {
		err = FILE_ERR_SOCK;
	}

	if (close(ifd)) {
		fprintf(stderr, "Error when closing %s: %s\n",
			filename, strerror(errno));
		return FILE_ERR_CLOSE;
	}

	return err;
}