/* Copyright 2018 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.
 *
 * Accessing updater resources from an archive.
 */

#include <assert.h>
#include <ctype.h>
#include <errno.h>
#if defined(__OpenBSD__)
#include <sys/types.h>
#endif
#include <fts.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <unistd.h>

#ifdef HAVE_LIBZIP
#ifndef __clang__
/* If libzip headers were built for Clang but later get included with GCC you
   need this. This check should really be in libzip but apparently they think
   it's fine to ship compiler-specific system headers or something... */
#define _Nullable
#define _Nonnull
#endif
#include <zip.h>
#endif

#ifdef HAVE_CROSID
#include <crosid.h>
#endif

#include "host_misc.h"
#include "updater.h"
#include "util_misc.h"

/*
 * A firmware update package (archive) is a file packed by either shar(1) or
 * zip(1). See https://chromium.googlesource.com/chromiumos/platform/firmware/
 * for more information.
 *
 * A package for single board (i.e., not Unified Build) will have all the image
 * files in top folder:
 *  - host: 'image.bin' (or 'bios.bin' as legacy name before CL:1318712)
 *  - ec: 'ec.bin'
 *  - pd: 'pd.bin'
 * If custom label is supported, a 'keyset/' folder will be available, with key
 * files in it:
 *  - rootkey.$CLTAG
 *  - vblock_A.$CLTAG
 *  - vblock_B.$CLTAG
 * The $CLTAG should come from VPD value 'custom_label_tag'. For legacy devices,
 * the VPD name may be 'whitelabel_tag', or 'customization_id'.
 * The 'customization_id' has a different format: LOEM[-VARIANT] and we can only
 * take LOEM as $CLTAG, for example A-B => $CLTAG=A.
 *
 * A package for Unified Build is more complicated. There will be a models/
 * folder, and each model (by $(mosys platform model) ) should appear as a sub
 * folder, with a 'setvars.sh' file inside. The 'setvars.sh' is a shell script
 * describing what files should be used and the signature ID ($SIGID) to use.
 *
 * Similar to custom label in non-Unified-Build, the keys and vblock files will
 * be in 'keyset/' folder:
 *  - rootkey.$SIGID
 *  - vblock_A.$SIGID
 *  - vblock_B.$SIGID
 * If $SIGID starts with 'sig-id-in-*' then we have to replace it by VPD value
 * 'custom_label_tag' as '$MODEL-$CLTAG'.
 */

static const char * const SETVARS_IMAGE_MAIN = "IMAGE_MAIN",
		  * const SETVARS_IMAGE_EC = "IMAGE_EC",
		  * const SETVARS_IMAGE_PD = "IMAGE_PD",
		  * const SETVARS_SIGNATURE_ID = "SIGNATURE_ID",
		  * const SIG_ID_IN_VPD_PREFIX = "sig-id-in",
		  * const DIR_KEYSET = "keyset",
		  * const DIR_MODELS = "models",
		  * const DEFAULT_MODEL_NAME = "default",
		  * const VPD_CUSTOM_LABEL_TAG = "custom_label_tag",
		  * const VPD_CUSTOM_LABEL_TAG_LEGACY = "whitelabel_tag",
		  * const VPD_CUSTOMIZATION_ID = "customization_id",
		  * const ENV_VAR_MODEL_DIR = "${MODEL_DIR}",
		  * const PATH_STARTSWITH_KEYSET = "keyset/",
		  * const PATH_ENDSWITH_SERVARS = "/setvars.sh";

struct archive {
	void *handle;

	void * (*open)(const char *name);
	int (*close)(void *handle);

	int (*walk)(void *handle, void *arg,
		    int (*callback)(const char *path, void *arg));
	int (*has_entry)(void *handle, const char *name);
	int (*read_file)(void *handle, const char *fname,
			 uint8_t **data, uint32_t *size, int64_t *mtime);
	int (*write_file)(void *handle, const char *fname,
			  uint8_t *data, uint32_t size, int64_t mtime);
};

/*
 * -- Begin of archive implementations --
 */

/* Callback for archive_open on a general file system. */
static void *archive_fallback_open(const char *name)
{
	assert(name && *name);
	return strdup(name);
}

/* Callback for archive_close on a general file system. */
static int archive_fallback_close(void *handle)
{
	free(handle);
	return 0;
}

/* Callback for archive_walk on a general file system. */
static int archive_fallback_walk(
		void *handle, void *arg,
		int (*callback)(const char *path, void *arg))
{
	FTS *fts_handle;
	FTSENT *ent;
	char *fts_argv[2] = {};
	char default_path[] = ".";
	char *root = default_path;
	size_t root_len;

	if (handle)
		root = (char *)handle;
	root_len = strlen(root);
	fts_argv[0] = root;

	fts_handle = fts_open(fts_argv, FTS_NOCHDIR, NULL);
	if (!fts_handle)
		return -1;

	while ((ent = fts_read(fts_handle)) != NULL) {
		char *path = ent->fts_path + root_len;
		if (ent->fts_info != FTS_F && ent->fts_info != FTS_SL)
			continue;
		while (*path == '/')
			path++;
		if (!*path)
			continue;
		if (callback(path, arg))
			break;
	}
	return 0;
}

/* Callback for fallback drivers to get full path easily. */
static const char *archive_fallback_get_path(void *handle, const char *fname,
					     char **temp_path)
{
	if (handle && *fname != '/') {
		ASPRINTF(temp_path, "%s/%s", (char *)handle, fname);
		return *temp_path;
	}
	return fname;
}

/* Callback for archive_has_entry on a general file system. */
static int archive_fallback_has_entry(void *handle, const char *fname)
{
	int r;
	char *temp_path = NULL;
	const char *path = archive_fallback_get_path(handle, fname, &temp_path);

	VB2_DEBUG("Checking %s\n", path);
	r = access(path, R_OK);
	free(temp_path);
	return r == 0;
}

/* Callback for archive_read_file on a general file system. */
static int archive_fallback_read_file(void *handle, const char *fname,
				      uint8_t **data, uint32_t *size, int64_t *mtime)
{
	int r;
	char *temp_path = NULL;
	const char *path = archive_fallback_get_path(handle, fname, &temp_path);
	struct stat st;

	VB2_DEBUG("Reading %s\n", path);
	*data = NULL;
	*size = 0;
	r = vb2_read_file(path, data, size) != VB2_SUCCESS;
	if (mtime) {
		if (stat(path, &st) == 0)
			*mtime = st.st_mtime;
		else
			WARN("Unable to stat %s: %s\n", path, strerror(errno));
	}
	free(temp_path);
	return r;
}

/* Callback for archive_write_file on a general file system. */
static int archive_fallback_write_file(void *handle, const char *fname,
				       uint8_t *data, uint32_t size, int64_t mtime)
{
	int r;
	char *temp_path = NULL;
	const char *path = archive_fallback_get_path(handle, fname, &temp_path);

	VB2_DEBUG("Writing %s\n", path);
	if (strchr(path, '/')) {
		char *dirname = strdup(path);
		*strrchr(dirname, '/') = '\0';
		/* TODO(hungte): call mkdir(2) instead of shell invocation. */
		if (access(dirname, W_OK) != 0) {
			char *command;
			ASPRINTF(&command, "mkdir -p %s", dirname);
			free(host_shell(command));
			free(command);
		}
		free(dirname);
	}
	r = vb2_write_file(path, data, size) != VB2_SUCCESS;
	if (mtime) {
		struct timeval times[2] = {
			{.tv_sec = mtime, .tv_usec = 0},
			{.tv_sec = mtime, .tv_usec = 0},
		};
		if (utimes(path, times) != 0)
			WARN("Unable to set times on %s: %s\n", path, strerror(errno));
	}
	free(temp_path);
	return r;
}

#ifdef HAVE_LIBZIP

/* Callback for archive_open on a ZIP file. */
static void *archive_zip_open(const char *name)
{
	return zip_open(name, 0, NULL);
}

/* Callback for archive_close on a ZIP file. */
static int archive_zip_close(void *handle)
{
	struct zip *zip = (struct zip *)handle;

	if (zip)
		return zip_close(zip);
	return 0;
}

/* Callback for archive_has_entry on a ZIP file. */
static int archive_zip_has_entry(void *handle, const char *fname)
{
	struct zip *zip = (struct zip *)handle;
	assert(zip);
	return zip_name_locate(zip, fname, 0) != -1;
}

/* Callback for archive_walk on a ZIP file. */
static int archive_zip_walk(
		void *handle, void *arg,
		int (*callback)(const char *name, void *arg))
{
	zip_int64_t num, i;
	struct zip *zip = (struct zip *)handle;
	assert(zip);

	num = zip_get_num_entries(zip, 0);
	if (num < 0)
		return 1;
	for (i = 0; i < num; i++) {
		const char *name = zip_get_name(zip, i, 0);
		if (*name && name[strlen(name) - 1] == '/')
			continue;
		if (callback(name, arg))
			break;
	}
	return 0;
}

/* Callback for archive_zip_read_file on a ZIP file. */
static int archive_zip_read_file(void *handle, const char *fname,
			     uint8_t **data, uint32_t *size, int64_t *mtime)
{
	struct zip *zip = (struct zip *)handle;
	struct zip_file *fp;
	struct zip_stat stat;

	assert(zip);
	*data = NULL;
	*size = 0;
	zip_stat_init(&stat);
	if (zip_stat(zip, fname, 0, &stat)) {
		ERROR("Fail to stat entry in ZIP: %s\n", fname);
		return 1;
	}
	fp = zip_fopen(zip, fname, 0);
	if (!fp) {
		ERROR("Failed to open entry in ZIP: %s\n", fname);
		return 1;
	}
	*data = (uint8_t *)malloc(stat.size);
	if (*data) {
		if (zip_fread(fp, *data, stat.size) == stat.size) {
			if (mtime)
				*mtime = stat.mtime;
			*size = stat.size;
		} else {
			ERROR("Failed to read entry in zip: %s\n", fname);
			free(*data);
			*data = NULL;
		}
	}
	zip_fclose(fp);
	return *data == NULL;
}

/* Callback for archive_zip_write_file on a ZIP file. */
static int archive_zip_write_file(void *handle, const char *fname,
				  uint8_t *data, uint32_t size, int64_t mtime)
{
	struct zip *zip = (struct zip *)handle;
	struct zip_source *src;

	VB2_DEBUG("Writing %s\n", fname);
	assert(zip);
	src = zip_source_buffer(zip, data, size, 0);
	if (!src) {
		ERROR("Internal error: cannot allocate buffer: %s\n", fname);
		return 1;
	}

	if (zip_file_add(zip, fname, src, ZIP_FL_OVERWRITE) < 0) {
		zip_source_free(src);
		ERROR("Internal error: failed to add: %s\n", fname);
		return 1;
	}
	/* zip_source_free is not needed if zip_file_add success. */
#if LIBZIP_VERSION_MAJOR >= 1
	zip_file_set_mtime(zip, zip_name_locate(zip, fname, 0), mtime, 0);
#endif
	return 0;
}
#endif

/*
 * Opens an archive from given path.
 * The type of archive will be determined automatically.
 * Returns a pointer to reference to archive (must be released by archive_close
 * when not used), otherwise NULL on error.
 */
struct archive *archive_open(const char *path)
{
	struct stat path_stat;
	struct archive *ar;

	if (stat(path, &path_stat) != 0) {
		ERROR("Cannot identify type of path: %s\n", path);
		return NULL;
	}

	ar = (struct archive *)malloc(sizeof(*ar));
	if (!ar) {
		ERROR("Internal error: allocation failure.\n");
		return NULL;
	}

	if (S_ISDIR(path_stat.st_mode)) {
		VB2_DEBUG("Found directory, use fallback (fs) driver: %s\n",
			  path);
		/* Regular file system. */
		ar->open = archive_fallback_open;
		ar->close = archive_fallback_close;
		ar->walk = archive_fallback_walk;
		ar->has_entry = archive_fallback_has_entry;
		ar->read_file = archive_fallback_read_file;
		ar->write_file = archive_fallback_write_file;
	} else {
#ifdef HAVE_LIBZIP
		VB2_DEBUG("Found file, use ZIP driver: %s\n", path);
		ar->open = archive_zip_open;
		ar->close = archive_zip_close;
		ar->walk = archive_zip_walk;
		ar->has_entry = archive_zip_has_entry;
		ar->read_file = archive_zip_read_file;
		ar->write_file = archive_zip_write_file;
#else
		ERROR("Found file, but no drivers were enabled: %s\n", path);
		free(ar);
		return NULL;
#endif
	}
	ar->handle = ar->open(path);
	if (!ar->handle) {
		ERROR("Failed to open archive: %s\n", path);
		free(ar);
		return NULL;
	}
	return ar;
}

/*
 * Closes an archive reference.
 * Returns 0 on success, otherwise non-zero as failure.
 */
int archive_close(struct archive *ar)
{
	int r = ar->close(ar->handle);
	free(ar);
	return r;
}

/*
 * Checks if an entry (either file or directory) exists in archive.
 * If entry name (fname) is an absolute path (/file), always check
 * with real file system.
 * Returns 1 if exists, otherwise 0
 */
int archive_has_entry(struct archive *ar, const char *name)
{
	if (!ar || *name == '/')
		return archive_fallback_has_entry(NULL, name);
	return ar->has_entry(ar->handle, name);
}

/*
 * Traverses all files within archive (directories are ignored).
 * For every entry, the path (relative the archive root) will be passed to
 * callback function, until the callback returns non-zero.
 * The arg argument will also be passed to callback.
 * Returns 0 on success otherwise non-zero as failure.
 */
static int archive_walk(struct archive *ar, void *arg,
			int (*callback)(const char *path, void *arg))
{
	if (!ar)
		return archive_fallback_walk(NULL, arg, callback);
	return ar->walk(ar->handle, arg, callback);
}

/*
 * Reads a file from archive.
 * If entry name (fname) is an absolute path (/file), always read
 * from real file system.
 * Returns 0 on success (data and size reflects the file content),
 * otherwise non-zero as failure.
 */
int archive_read_file(struct archive *ar, const char *fname,
		      uint8_t **data, uint32_t *size, int64_t *mtime)
{
	if (!ar || *fname == '/')
		return archive_fallback_read_file(NULL, fname, data, size, mtime);
	return ar->read_file(ar->handle, fname, data, size, mtime);
}

/*
 * Writes a file into archive.
 * If entry name (fname) is an absolute path (/file), always write into real
 * file system.
 * Returns 0 on success, otherwise non-zero as failure.
 */
int archive_write_file(struct archive *ar, const char *fname,
		       uint8_t *data, uint32_t size, int64_t mtime)
{
	if (!ar || *fname == '/')
		return archive_fallback_write_file(NULL, fname, data, size, mtime);
	return ar->write_file(ar->handle, fname, data, size, mtime);
}

struct _copy_arg {
	struct archive *from, *to;
};

/* Callback for archive_copy. */
static int archive_copy_callback(const char *path, void *_arg)
{
	const struct _copy_arg *arg = (const struct _copy_arg*)_arg;
	uint32_t size;
	uint8_t *data;
	int64_t mtime;
	int r;

	INFO("Copying: %s\n", path);
	if (archive_read_file(arg->from, path, &data, &size, &mtime)) {
		ERROR("Failed reading: %s\n", path);
		return 1;
	}
	r = archive_write_file(arg->to, path, data, size, mtime);
	VB2_DEBUG("result=%d\n", r);
	free(data);
	return r;
}

/*
 * Copies all entries from one archive to another.
 * Returns 0 on success, otherwise non-zero as failure.
 */
int archive_copy(struct archive *from, struct archive *to)
{
	struct _copy_arg arg = { .from = from, .to = to };
	return archive_walk(from, &arg, archive_copy_callback);
}

/*
 * -- End of archive implementations --
 */

/* Utility function to convert a string. */
static void str_convert(char *s, int (*convert)(int c))
{
	int c;

	for (; *s; s++) {
		c = *s;
		if (!isascii(c))
			continue;
		*s = convert(c);
	}
}

/* Returns 1 if name ends by given pattern, otherwise 0. */
static int str_endswith(const char *name, const char *pattern)
{
	size_t name_len = strlen(name), pattern_len = strlen(pattern);
	if (name_len < pattern_len)
		return 0;
	return strcmp(name + name_len - pattern_len, pattern) == 0;
}

/* Returns 1 if name starts by given pattern, otherwise 0. */
static int str_startswith(const char *name, const char *pattern)
{
	return strncmp(name, pattern, strlen(pattern)) == 0;
}

/* Returns the VPD value by given key name, or NULL on error (or no value). */
static char *vpd_get_value(const char *fpath, const char *key)
{
	char *command, *result;

	assert(fpath);
	ASPRINTF(&command, "vpd -g %s -f %s 2>/dev/null", key, fpath);
	result = host_shell(command);
	free(command);

	if (result && !*result) {
		free(result);
		result = NULL;
	}
	return result;
}

/*
 * Reads and parses a setvars type file from archive, then stores into config.
 * Returns 0 on success (at least one entry found), otherwise failure.
 */
static int model_config_parse_setvars_file(
		struct model_config *cfg, struct archive *archive,
		const char *fpath)
{
	uint8_t *data;
	uint32_t len;

	char *ptr_line, *ptr_token;
	char *line, *k, *v;
	int valid = 0;

	if (archive_read_file(archive, fpath, &data, &len, NULL) != 0) {
		ERROR("Failed reading: %s\n", fpath);
		return -1;
	}

	/* Valid content should end with \n, or \"; ensure ASCIIZ for parsing */
	if (len)
		data[len - 1] = '\0';

	for (line = strtok_r((char *)data, "\n\r", &ptr_line); line;
	     line = strtok_r(NULL, "\n\r", &ptr_line)) {
		char *expand_path = NULL;
		int found_valid = 1;

		/* Format: KEY="value" */
		k = strtok_r(line, "=", &ptr_token);
		if (!k)
			continue;
		v = strtok_r(NULL, "\"", &ptr_token);
		if (!v)
			continue;

		/* Some legacy updaters may be still using ${MODEL_DIR}. */
		if (str_startswith(v, ENV_VAR_MODEL_DIR)) {
			ASPRINTF(&expand_path, "%s/%s%s", DIR_MODELS, cfg->name,
				 v + strlen(ENV_VAR_MODEL_DIR));
		}

		if (strcmp(k, SETVARS_IMAGE_MAIN) == 0)
			cfg->image = strdup(v);
		else if (strcmp(k, SETVARS_IMAGE_EC) == 0)
			cfg->ec_image = strdup(v);
		else if (strcmp(k, SETVARS_IMAGE_PD) == 0)
			cfg->pd_image = strdup(v);
		else if (strcmp(k, SETVARS_SIGNATURE_ID) == 0) {
			cfg->signature_id = strdup(v);
			if (str_startswith(v, SIG_ID_IN_VPD_PREFIX))
				cfg->is_custom_label = 1;
		} else
			found_valid = 0;
		free(expand_path);
		valid += found_valid;
	}
	free(data);
	return valid == 0;
}

/*
 * Changes the rootkey in firmware GBB to given new key.
 * Returns 0 on success, otherwise failure.
 */
static int change_gbb_rootkey(struct firmware_image *image,
			      const char *section_name,
			      const uint8_t *rootkey, uint32_t rootkey_len)
{
	const struct vb2_gbb_header *gbb = find_gbb(image);
	uint8_t *gbb_rootkey;
	if (!gbb) {
		ERROR("Cannot find GBB in image %s.\n", image->file_name);
		return -1;
	}
	if (gbb->rootkey_size < rootkey_len) {
		ERROR("New root key (%u bytes) larger than GBB (%u bytes).\n",
		      rootkey_len, gbb->rootkey_size);
		return -1;
	}

	gbb_rootkey = (uint8_t *)gbb + gbb->rootkey_offset;
	/* See cmd_gbb_utility: root key must be first cleared with zero. */
	memset(gbb_rootkey, 0, gbb->rootkey_size);
	memcpy(gbb_rootkey, rootkey, rootkey_len);
	return 0;
}

/*
 * Changes the VBlock in firmware section to new data.
 * Returns 0 on success, otherwise failure.
 */
static int change_vblock(struct firmware_image *image, const char *section_name,
			 const uint8_t *vblock, uint32_t vblock_len)
{
	struct firmware_section section;

	find_firmware_section(&section, image, section_name);
	if (!section.data) {
		ERROR("Need section %s in image %s.\n", section_name,
		      image->file_name);
		return -1;
	}
	if (section.size < vblock_len) {
		ERROR("Section %s too small (%zu bytes) for vblock (%u bytes).\n",
		      section_name, section.size, vblock_len);
		return -1;
	}
	memcpy(section.data, vblock, vblock_len);
	return 0;
}

/*
 * Applies a key file to firmware image.
 * Returns 0 on success, otherwise failure.
 */
static int apply_key_file(
		struct firmware_image *image, const char *path,
		struct archive *archive, const char *section_name,
		int (*apply)(struct firmware_image *image, const char *section,
			     const uint8_t *data, uint32_t len))
{
	int r = 0;
	uint8_t *data = NULL;
	uint32_t len;

	r = archive_read_file(archive, path, &data, &len, NULL);
	if (r == 0) {
		VB2_DEBUG("Loaded file: %s\n", path);
		r = apply(image, section_name, data, len);
		if (r)
			ERROR("Failed applying %s to %s\n", path, section_name);
	} else {
		ERROR("Failed reading: %s\n", path);
	}
	free(data);
	return r;
}

/*
 * Modifies a firmware image from patch information specified in model config.
 * Returns 0 on success, otherwise number of failures.
 */
int patch_image_by_model(
		struct firmware_image *image, const struct model_config *model,
		struct archive *archive)
{
	int err = 0;
	if (model->patches.rootkey)
		err += !!apply_key_file(
				image, model->patches.rootkey, archive,
				FMAP_RO_GBB, change_gbb_rootkey);
	if (model->patches.vblock_a)
		err += !!apply_key_file(
				image, model->patches.vblock_a, archive,
				FMAP_RW_VBLOCK_A, change_vblock);
	if (model->patches.vblock_b)
		err += !!apply_key_file(
				image, model->patches.vblock_b, archive,
				FMAP_RW_VBLOCK_B, change_vblock);
	return err;
}

/*
 * Finds available patch files by given model.
 * Updates `model` argument with path of patch files.
 */
static void find_patches_for_model(struct model_config *model,
				   struct archive *archive,
				   const char *signature_id)
{
	char *path;
	int i;

	const char *names[] = {
		"rootkey",
		"vblock_A",
		"vblock_B",
	};

	char **targets[] = {
		&model->patches.rootkey,
		&model->patches.vblock_a,
		&model->patches.vblock_b,
	};

	assert(ARRAY_SIZE(names) == ARRAY_SIZE(targets));
	for (i = 0; i < ARRAY_SIZE(names); i++) {
		ASPRINTF(&path, "%s/%s.%s", DIR_KEYSET, names[i], signature_id);
		if (archive_has_entry(archive, path))
			*targets[i] = path;
		else
			free(path);
	}
}

/*
 * Adds and copies one new model config to the existing list of given manifest.
 * Returns a pointer to the newly allocated config, or NULL on failure.
 */
static struct model_config *manifest_add_model(
		struct manifest *manifest,
		const struct model_config *cfg)
{
	struct model_config *model;
	manifest->num++;
	manifest->models = (struct model_config *)realloc(
			manifest->models, manifest->num * sizeof(*model));
	if (!manifest->models) {
		ERROR("Internal error: failed to allocate buffer.\n");
		return NULL;
	}
	model = &manifest->models[manifest->num - 1];
	memcpy(model, cfg, sizeof(*model));
	return model;
}

/*
 * A callback function for manifest to scan files in archive.
 * Returns 0 to keep scanning, or non-zero to stop.
 */
static int manifest_scan_entries(const char *name, void *arg)
{
	struct manifest *manifest = (struct manifest *)arg;
	struct archive *archive = manifest->archive;
	struct model_config model = {0};
	char *slash;

	if (str_startswith(name, PATH_STARTSWITH_KEYSET))
		manifest->has_keyset = 1;
	if (!str_endswith(name, PATH_ENDSWITH_SERVARS))
		return 0;

	/* name: models/$MODEL/setvars.sh */
	model.name = strdup(strchr(name, '/') + 1);
	slash = strchr(model.name, '/');
	if (slash)
		*slash = '\0';

	VB2_DEBUG("Found model <%s> setvars: %s\n", model.name, name);
	if (model_config_parse_setvars_file(&model, archive, name)) {
		ERROR("Invalid setvars file: %s\n", name);
		return 0;
	}

	/* In legacy setvars.sh, the ec_image and pd_image may not exist. */
	if (model.ec_image && !archive_has_entry(archive, model.ec_image)) {
		VB2_DEBUG("Ignore non-exist EC image: %s\n", model.ec_image);
		free(model.ec_image);
		model.ec_image = NULL;
	}
	if (model.pd_image && !archive_has_entry(archive, model.pd_image)) {
		VB2_DEBUG("Ignore non-exist PD image: %s\n", model.pd_image);
		free(model.pd_image);
		model.pd_image = NULL;
	}

	/* Find patch files. */
	if (model.signature_id)
		find_patches_for_model(&model, archive, model.signature_id);

	return !manifest_add_model(manifest, &model);
}

/**
 * get_manifest_key() - Wrapper to get the firmware manifest key from crosid
 *
 * @manifest_key_out - Output parameter of the firmware manifest key.
 *
 * Returns:
 * - <0 if libcrosid is unavailable or there was an error reading
 *   device data
 * - >=0 (the matched device index) success
 */
static int get_manifest_key(char **manifest_key_out)
{
#ifdef HAVE_CROSID
	return crosid_get_firmware_manifest_key(manifest_key_out);
#else
	ERROR("This version of futility was compiled without libcrosid "
	      "(perhaps compiled outside of the Chrome OS build system?) and "
	      "the update command is not fully supported.  Either compile "
	      "from the Chrome OS build, or pass --model to manually specify "
	      "the machine model.\n");
	return -1;
#endif
}

/*
 * Finds the existing model_config from manifest that best matches current
 * system (as defined by model_name).
 * Returns a model_config from manifest, or NULL if not found.
 */
const struct model_config *manifest_find_model(const struct manifest *manifest,
					       const char *model_name)
{
	char *manifest_key = NULL;
	const struct model_config *model = NULL;
	int i;
	int matched_index;

	/*
	 * For manifest with single model defined, we should just return because
	 * there are other mechanisms like platform name check to double confirm
	 * if the firmware is valid.
	 */
	if (manifest->num == 1)
		return &manifest->models[0];

	if (!model_name) {
		matched_index = get_manifest_key(&manifest_key);
		if (matched_index < 0) {
			ERROR("Failed to get device identity.  "
			      "Run \"crosid -v\" for explanation.\n");
			return NULL;
		}

		INFO("Identified the device using libcrosid, "
		     "matched chromeos-config index: %d, "
		     "manifest key (model): %s\n",
		     matched_index, manifest_key);
		model_name = manifest_key;
	}

	for (i = 0; !model && i < manifest->num; i++) {
		if (strcmp(model_name, manifest->models[i].name) == 0)
			model = &manifest->models[i];
	}
	if (!model) {
		ERROR("Unsupported model: '%s'.\n", model_name);

		fprintf(stderr,
			"The firmware manifest key '%s' is not present in this "
			"updater archive. The known keys to this updater "
			"archive are:\n", model_name);

		for (i = 0; i < manifest->num; i++)
			fprintf(stderr, " %s", manifest->models[i].name);
		fprintf(stderr, "\n\n");
		fprintf(stderr,
			"Perhaps you are trying to use an updater archive for "
			"the wrong board, or designed for an older OS version "
			"before this model was supported.\n");
		fprintf(stderr,
			"Hint: Read the FIRMWARE_MANIFEST_KEY from the output "
			"of the crosid command.\n");
	}


	free(manifest_key);
	return model;
}

/*
 * Determines the signature ID to use for custom label.
 * Returns the signature ID for looking up rootkey and vblock files.
 * Caller must free the returned string.
 */
static char *resolve_signature_id(struct model_config *model, const char *image)
{
	int is_unibuild = model->signature_id ? 1 : 0;
	char *tag = vpd_get_value(image, VPD_CUSTOM_LABEL_TAG);
	char *sig_id = NULL;

	if (tag == NULL)
		tag = vpd_get_value(image, VPD_CUSTOM_LABEL_TAG_LEGACY);

	/* Unified build: $model.$tag, or $model (b/126800200). */
	if (is_unibuild) {
		if (!tag) {
			WARN("No VPD '%s' set for custom label. "
			     "Use model name '%s' as default.\n",
			     VPD_CUSTOM_LABEL_TAG, model->name);
			return strdup(model->name);
		}

		ASPRINTF(&sig_id, "%s-%s", model->name, tag);
		free(tag);
		return sig_id;
	}

	/* Non-Unibuild: Upper($tag), or Upper(${cid%%-*}). */
	if (!tag) {
		char *cid = vpd_get_value(image, VPD_CUSTOMIZATION_ID);
		if (cid) {
			/* customization_id in format LOEM[-VARIANT]. */
			char *dash = strchr(cid, '-');
			if (dash)
				*dash = '\0';
			tag = cid;
		}
	}
	if (tag)
		str_convert(tag, toupper);
	return tag;
}

/*
 * Applies custom label information to an existing model configuration.
 * Collects signature ID information from either parameter signature_id or
 * image file (via VPD) and updates model.patches for key files.
 * Returns 0 on success, otherwise failure.
 */
int model_apply_custom_label(
		struct model_config *model,
		struct archive *archive,
		const char *signature_id,
		const char *image)
{
	char *sig_id = NULL;
	int r = 0;

	if (!signature_id) {
		sig_id = resolve_signature_id(model, image);
		signature_id = sig_id;
	}

	if (signature_id) {
		VB2_DEBUG("Find custom label patches by signature ID: '%s'.\n",
		      signature_id);
		find_patches_for_model(model, archive, signature_id);
	} else {
		signature_id = "";
		WARN("No VPD '%s' set for custom label - use default keys.\n",
		     VPD_CUSTOM_LABEL_TAG);
	}
	if (!model->patches.rootkey) {
		ERROR("No keys found for signature_id: '%s'\n", signature_id);
		r = 1;
	} else {
		INFO("Applied for custom label: %s\n", signature_id);
	}
	free(sig_id);
	return r;
}

/*
 * Creates a new manifest object by scanning files in archive.
 * Returns the manifest on success, otherwise NULL for failure.
 */
struct manifest *new_manifest_from_archive(struct archive *archive)
{
	struct manifest manifest = {0}, *new_manifest;
	struct model_config model = {0};
	const char * const host_image_name = "image.bin",
		   * const old_host_image_name = "bios.bin",
	           * const ec_name = "ec.bin",
		   * const pd_name = "pd.bin";

	manifest.archive = archive;
	manifest.default_model = -1;
	archive_walk(archive, &manifest, manifest_scan_entries);
	if (manifest.num == 0) {
		const char *image_name = NULL;
		struct firmware_image image = {0};

		/* Try to load from current folder. */
		if (archive_has_entry(archive, old_host_image_name))
			image_name = old_host_image_name;
		else if (archive_has_entry(archive, host_image_name))
			image_name = host_image_name;
		else
			return 0;

		model.image = strdup(image_name);
		if (archive_has_entry(archive, ec_name))
			model.ec_image = strdup(ec_name);
		if (archive_has_entry(archive, pd_name))
			model.pd_image = strdup(pd_name);
		/* Extract model name from FWID: $Vendor_$Platform.$Version */
		if (!load_firmware_image(&image, image_name, archive)) {
			char *token = NULL;
			if (strtok(image.ro_version, "_"))
				token = strtok(NULL, ".");
			if (token && *token) {
				str_convert(token, tolower);
				model.name = strdup(token);
			}
			free_firmware_image(&image);
		}
		if (!model.name)
			model.name = strdup(DEFAULT_MODEL_NAME);
		if (manifest.has_keyset)
			model.is_custom_label = 1;
		manifest_add_model(&manifest, &model);
		manifest.default_model = manifest.num - 1;
	}
	VB2_DEBUG("%d model(s) loaded.\n", manifest.num);
	if (!manifest.num) {
		ERROR("No valid configurations found from archive.\n");
		return NULL;
	}

	new_manifest = (struct manifest *)malloc(sizeof(manifest));
	if (!new_manifest) {
		ERROR("Internal error: memory allocation error.\n");
		return NULL;
	}
	memcpy(new_manifest, &manifest, sizeof(manifest));
	return new_manifest;
}

/* Releases all resources allocated by given manifest object. */
void delete_manifest(struct manifest *manifest)
{
	int i;
	assert(manifest);
	for (i = 0; i < manifest->num; i++) {
		struct model_config *model = &manifest->models[i];
		free(model->name);
		free(model->signature_id);
		free(model->image);
		free(model->ec_image);
		free(model->pd_image);
		free(model->patches.rootkey);
		free(model->patches.vblock_a);
		free(model->patches.vblock_b);
	}
	free(manifest->models);
	free(manifest);
}

static const char *get_gbb_key_hash(const struct vb2_gbb_header *gbb,
				    int32_t offset, int32_t size)
{
	struct vb2_packed_key *key;

	if (!gbb)
		return "<No GBB>";
	key = (struct vb2_packed_key *)((uint8_t *)gbb + offset);
	if (vb2_packed_key_looks_ok(key, size))
		return "<Invalid key>";
	return packed_key_sha1_string(key);
}

/* Prints the information of given image file in JSON format. */
static void print_json_image(
		const char *name, const char *fpath, struct model_config *m,
		struct archive *archive, int indent, int is_host)
{
	struct firmware_image image = {0};
	const struct vb2_gbb_header *gbb = NULL;
	if (!fpath)
		return;
	if (load_firmware_image(&image, fpath, archive))
		return;
	if (!is_host)
		printf(",\n");
	printf("%*s\"%s\": { \"versions\": { \"ro\": \"%s\", \"rw\": \"%s\" },",
	       indent, "", name, image.ro_version, image.rw_version_a);
	indent += 2;
	if (!is_host) {
		/* No extra information to be printed */
        } else if (patch_image_by_model(&image, m, archive) != 0) {
		ERROR("Failed to patch images by model: %s\n", m->name);
	} else if (NULL != (gbb = find_gbb(&image))) {
		printf("\n%*s\"keys\": { \"root\": \"%s\", ",
		       indent, "",
		       get_gbb_key_hash(gbb, gbb->rootkey_offset,
					gbb->rootkey_size));
		printf("\"recovery\": \"%s\" },",
		       get_gbb_key_hash(gbb, gbb->recovery_key_offset,
					gbb->recovery_key_size));
	}
	printf("\n%*s\"image\": \"%s\" }", indent, "", fpath);
	free_firmware_image(&image);
}

/* Prints the information of objects in manifest (models and images) in JSON. */
void print_json_manifest(const struct manifest *manifest)
{
	int i, indent;
	struct archive *ar = manifest->archive;

	printf("{\n");
	for (i = 0, indent = 2; i < manifest->num; i++) {
		struct model_config *m = &manifest->models[i];
		printf("%s%*s\"%s\": {\n", i ? ",\n" : "", indent, "", m->name);
		indent += 2;
		print_json_image("host", m->image, m, ar, indent, 1);
		print_json_image("ec", m->ec_image, m, ar, indent, 0);
		print_json_image("pd", m->pd_image, m, ar, indent, 0);
		if (m->patches.rootkey) {
			struct patch_config *p = &m->patches;
			printf(",\n%*s\"patches\": { \"rootkey\": \"%s\", "
			       "\"vblock_a\": \"%s\", \"vblock_b\": \"%s\" }",
			       indent, "", p->rootkey, p->vblock_a,
			       p->vblock_b);
		}
		if (m->signature_id)
			printf(",\n%*s\"signature_id\": \"%s\"", indent, "",
			       m->signature_id);
		printf("\n  }");
		indent -= 2;
		assert(indent == 2);
	}
	printf("\n}\n");
}