/*
 * ntfs-capture.c
 *
 * Capture a WIM image from a NTFS volume.  We capture everything we can,
 * including security data and alternate data streams.  There should be no loss
 * of information.
 */

/*
 * Copyright (C) 2012 Eric Biggers
 *
 * This file is part of wimlib, a library for working with WIM files.
 *
 * wimlib is free software; you can redistribute it and/or modify it under the
 * terms of the GNU Lesser General Public License as published by the Free
 * Software Foundation; either version 2.1 of the License, or (at your option)
 * any later version.
 *
 * wimlib 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 Lesser General Public License for more
 * details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with wimlib; if not, see http://www.gnu.org/licenses/.
 */

#include "config.h"
#include "wimlib_internal.h"


#ifdef WITH_NTFS_3G
#include "dentry.h"
#include "lookup_table.h"
#include "io.h"
#include <ntfs-3g/layout.h>
#include <ntfs-3g/acls.h>
#include <ntfs-3g/attrib.h>
#include <ntfs-3g/misc.h>
#include <ntfs-3g/reparse.h>
#include <ntfs-3g/security.h>
#include <ntfs-3g/volume.h>
#include <stdlib.h>
#include <unistd.h>

extern int ntfs_inode_get_security(ntfs_inode *ni, u32 selection, char *buf,
				   u32 buflen, u32 *psize);

extern int ntfs_inode_get_attributes(ntfs_inode *ni);

/* Structure that allows searching the security descriptors by SHA1 message
 * digest. */
struct sd_set {
	struct wim_security_data *sd;
	struct sd_node *root;
};

/* Binary tree node of security descriptors, indexed by the @hash field. */
struct sd_node {
	int security_id;
	u8 hash[SHA1_HASH_SIZE];
	struct sd_node *left;
	struct sd_node *right;
};

static void free_sd_tree(struct sd_node *root)
{
	if (root) {
		free_sd_tree(root->left);
		free_sd_tree(root->right);
		FREE(root);
	}
}
/* Frees a security descriptor index set. */
static void destroy_sd_set(struct sd_set *sd_set)
{
	free_sd_tree(sd_set->root);
}

/* Inserts a a new node into the security descriptor index tree. */
static void insert_sd_node(struct sd_node *new, struct sd_node *root)
{
	int cmp = hashes_cmp(new->hash, root->hash);
	if (cmp < 0) {
		if (root->left)
			insert_sd_node(new, root->left);
		else 
			root->left = new;
	} else if (cmp > 0) {
		if (root->right)
			insert_sd_node(new, root->right);
		else 
			root->right = new;
	} else {
		wimlib_assert(0);
	}
}

/* Returns the security ID of the security data having a SHA1 message digest of
 * @hash in the security descriptor index tree rooted at @root. 
 *
 * If not found, return -1. */
static int lookup_sd(const u8 hash[SHA1_HASH_SIZE], struct sd_node *root)
{
	int cmp;
	if (!root)
		return -1;
	cmp = hashes_cmp(hash, root->hash);
	if (cmp < 0)
		return lookup_sd(hash, root->left);
	else if (cmp > 0)
		return lookup_sd(hash, root->right);
	else
		return root->security_id;
}

/*
 * Adds a security descriptor to the indexed security descriptor set as well as
 * the corresponding `struct wim_security_data', and returns the new security
 * ID; or, if there is an existing security descriptor that is the same, return
 * the security ID for it.  If a new security descriptor cannot be allocated,
 * return -1.
 */
static int sd_set_add_sd(struct sd_set *sd_set, const u8 *descriptor,
		         size_t size)
{
	u8 hash[SHA1_HASH_SIZE];
	int security_id;
	struct sd_node *new;
	u8 **descriptors;
	u64 *sizes;
	u8 *descr_copy;
	struct wim_security_data *sd;

	sha1_buffer(descriptor, size, hash);
	security_id = lookup_sd(hash, sd_set->root);
	if (security_id >= 0)
		return security_id;

	new = MALLOC(sizeof(*new));
	if (!new)
		goto out;
	descr_copy = MALLOC(size);
	if (!descr_copy)
		goto out_free_node;

	sd = sd_set->sd;

	memcpy(descr_copy, descriptor, size);
	new->security_id = sd->num_entries;
	new->left = NULL;
	new->right = NULL;
	copy_hash(new->hash, hash);


	descriptors = REALLOC(sd->descriptors,
			      (sd->num_entries + 1) * sizeof(sd->descriptors[0]));
	if (!descriptors)
		goto out_free_descr;
	sd->descriptors = descriptors;
	sizes = REALLOC(sd->sizes,
			(sd->num_entries + 1) * sizeof(sd->sizes[0]));
	if (!sizes)
		goto out_free_descr;
	sd->sizes = sizes;
	sd->descriptors[sd->num_entries] = descr_copy;
	sd->sizes[sd->num_entries] = size;
	sd->num_entries++;
	sd->total_length += size + sizeof(sd->sizes[0]);

	if (sd_set->root)
		insert_sd_node(sd_set->root, new);
	else
		sd_set->root = new;
	return new->security_id;
out_free_descr:
	FREE(descr_copy);
out_free_node:
	FREE(new);
out:
	return -1;
}

static inline ntfschar *attr_record_name(ATTR_RECORD *ar)
{
	return (ntfschar*)((u8*)ar + le16_to_cpu(ar->name_offset));
}

/* Calculates the SHA1 message digest of a NTFS attribute. 
 *
 * @ni:  The NTFS inode containing the attribute.
 * @ar:	 The ATTR_RECORD describing the attribute.
 * @md:  If successful, the returned SHA1 message digest.
 *
 * Return 0 on success or nonzero on error.
 */
static int ntfs_attr_sha1sum(ntfs_inode *ni, ATTR_RECORD *ar,
			     u8 md[SHA1_HASH_SIZE])
{
	s64 pos = 0;
	s64 bytes_remaining;
	char buf[4096];
	ntfs_attr *na;
	SHA_CTX ctx;

	na = ntfs_attr_open(ni, ar->type, attr_record_name(ar),
			    ar->name_length);
	if (!na) {
		ERROR_WITH_ERRNO("Failed to open NTFS attribute");
		return WIMLIB_ERR_NTFS_3G;
	}

	bytes_remaining = na->data_size;
	sha1_init(&ctx);

	DEBUG("Calculating SHA1 message digest (%"PRIu64" bytes)",
			bytes_remaining);

	while (bytes_remaining) {
		s64 to_read = min(bytes_remaining, sizeof(buf));
		if (ntfs_attr_pread(na, pos, to_read, buf) != to_read) {
			ERROR_WITH_ERRNO("Error reading NTFS attribute");
			return WIMLIB_ERR_NTFS_3G;
		}
		sha1_update(&ctx, buf, to_read);
		pos += to_read;
		bytes_remaining -= to_read;
	}
	sha1_final(md, &ctx);
	ntfs_attr_close(na);
	return 0;
}

/* Load the streams from a WIM file or reparse point in the NTFS volume into the
 * WIM lookup table */
static int capture_ntfs_streams(struct dentry *dentry, ntfs_inode *ni,
				char path[], size_t path_len,
				struct lookup_table *lookup_table,
				ntfs_volume **ntfs_vol_p,
				ATTR_TYPES type)
{

	ntfs_attr_search_ctx *actx;
	u8 attr_hash[SHA1_HASH_SIZE];
	struct ntfs_location *ntfs_loc;
	struct lookup_table_entry *lte;
	int ret = 0;

	DEBUG("Capturing NTFS data streams from `%s'", path);

	/* Get context to search the streams of the NTFS file. */
	actx = ntfs_attr_get_search_ctx(ni, NULL);
	if (!actx) {
		ERROR_WITH_ERRNO("Cannot get attribute search "
				 "context");
		return WIMLIB_ERR_NTFS_3G;
	}

	/* Capture each data stream or reparse data stream. */
	while (!ntfs_attr_lookup(type, NULL, 0,
				 CASE_SENSITIVE, 0, NULL, 0, actx))
	{
		char *stream_name_utf8;
		size_t stream_name_utf16_len;

		/* Checksum the stream. */
		ret = ntfs_attr_sha1sum(ni, actx->attr, attr_hash);
		if (ret != 0)
			goto out_put_actx;

		/* Make a lookup table entry for the stream, or use an existing
		 * one if there's already an identical stream. */
		lte = __lookup_resource(lookup_table, attr_hash);
		ret = WIMLIB_ERR_NOMEM;
		if (lte) {
			lte->refcnt++;
		} else {
			struct ntfs_location *ntfs_loc;

			ntfs_loc = CALLOC(1, sizeof(*ntfs_loc));
			if (!ntfs_loc)
				goto out_put_actx;
			ntfs_loc->ntfs_vol_p = ntfs_vol_p;
			ntfs_loc->path_utf8 = MALLOC(path_len + 1);
			if (!ntfs_loc->path_utf8)
				goto out_free_ntfs_loc;
			memcpy(ntfs_loc->path_utf8, path, path_len + 1);
			ntfs_loc->stream_name_utf16 = MALLOC(actx->attr->name_length * 2);
			if (!ntfs_loc->stream_name_utf16)
				goto out_free_ntfs_loc;
			memcpy(ntfs_loc->stream_name_utf16,
			       attr_record_name(actx->attr),
			       actx->attr->name_length * 2);

			ntfs_loc->stream_name_utf16_num_chars = actx->attr->name_length;
			ntfs_loc->is_reparse_point = (type == AT_REPARSE_POINT);
			lte = new_lookup_table_entry();
			if (!lte)
				goto out_free_ntfs_loc;
			lte->ntfs_loc = ntfs_loc;
			lte->resource_location = RESOURCE_IN_NTFS_VOLUME;
			lte->resource_entry.original_size = actx->attr->data_size;
			lte->resource_entry.size = actx->attr->data_size;
			DEBUG("Add resource for `%s' (size = %zu)",
				dentry->file_name_utf8,
				lte->resource_entry.original_size);
			copy_hash(lte->hash, attr_hash);
			lookup_table_insert(lookup_table, lte);
		}
		if (actx->attr->name_length == 0) {
			if (dentry->lte) {
				ERROR("Found two un-named data streams for "
				      "`%s'", path);
				ret = WIMLIB_ERR_NTFS_3G;
				goto out_free_lte;
			}
			dentry->lte = lte;
		} else {
			struct ads_entry *new_ads_entry;
			stream_name_utf8 = utf16_to_utf8((const u8*)attr_record_name(actx->attr),
							 actx->attr->name_length,
							 &stream_name_utf16_len);
			if (!stream_name_utf8)
				goto out_free_lte;
			new_ads_entry = dentry_add_ads(dentry, stream_name_utf8);
			FREE(stream_name_utf8);
			if (!new_ads_entry)
				goto out_free_lte;
				
			new_ads_entry->lte = lte;
		}
	}
	ret = 0;
	goto out_put_actx;
out_free_lte:
	free_lookup_table_entry(lte);
out_free_ntfs_loc:
	if (ntfs_loc) {
		FREE(ntfs_loc->path_utf8);
		FREE(ntfs_loc->stream_name_utf16);
		FREE(ntfs_loc);
	}
out_put_actx:
	ntfs_attr_put_search_ctx(actx);
	if (ret == 0)
		DEBUG("Successfully captured NTFS streams from `%s'", path);
	else
		DEBUG("Failed to capture NTFS streams from `%s", path);
	return ret;
}

struct readdir_ctx {
	struct dentry	    *parent;
	ntfs_inode	    *dir_ni;
	char		    *path;
	size_t		     path_len;
	struct lookup_table *lookup_table;
	struct sd_set	    *sd_set;
	const struct capture_config *config;
	ntfs_volume	   **ntfs_vol_p;
};

static int __build_dentry_tree_ntfs(struct dentry **root_p, ntfs_inode *ni,
				    char path[], size_t path_len,
				    struct lookup_table *lookup_table,
				    struct sd_set *sd_set,
				    const struct capture_config *config,
				    ntfs_volume **ntfs_vol_p);


static int wim_ntfs_capture_filldir(void *dirent, const ntfschar *name,
				    const int name_len, const int name_type,
				    const s64 pos, const MFT_REF mref,
				    const unsigned dt_type)
{
	struct readdir_ctx *ctx;
	size_t utf8_name_len;
	char *utf8_name;
	struct dentry *child = NULL;
	int ret;
	size_t path_len;

	if (name_type == FILE_NAME_DOS)
		return 0;

	ret = -1;

 	utf8_name = utf16_to_utf8((const u8*)name, name_len * 2,
				  &utf8_name_len);
	if (!utf8_name)
		goto out;

	if (utf8_name[0] == '.' &&
	     (utf8_name[1] == '\0' ||
	      (utf8_name[1] == '.' && utf8_name[2] == '\0'))) {
		DEBUG("Skipping dentry `%s'", utf8_name);
		ret = 0;
		goto out_free_utf8_name;
	}

	DEBUG("Opening inode for `%s'", utf8_name);

	ctx = dirent;

	ntfs_inode *ni = ntfs_inode_open(ctx->dir_ni->vol, mref);
	if (!ni) {
		ERROR_WITH_ERRNO("Failed to open NTFS inode");
		ret = 1;
	}
	path_len = ctx->path_len;
	if (path_len != 1)
		ctx->path[path_len++] = '/';
	memcpy(ctx->path + path_len, utf8_name, utf8_name_len + 1);
	path_len += utf8_name_len;
	ret = __build_dentry_tree_ntfs(&child, ni, ctx->path, path_len,
				       ctx->lookup_table, ctx->sd_set,
				       ctx->config, ctx->ntfs_vol_p);

	if (child) {
		DEBUG("Linking dentry `%s' with parent `%s'",
		      child->file_name_utf8, ctx->parent->file_name_utf8);
		link_dentry(child, ctx->parent);
	}
out_close_ni:
	ntfs_inode_close(ni);
out_free_utf8_name:
	FREE(utf8_name);
out:
	return ret;
}

/* Recursively build a WIM dentry tree corresponding to a NTFS volume.
 * At the same time, update the WIM lookup table with lookup table entries for
 * the NTFS streams, and build an array of security descriptors.
 */
static int __build_dentry_tree_ntfs(struct dentry **root_p, ntfs_inode *ni,
				    char path[], size_t path_len,
				    struct lookup_table *lookup_table,
				    struct sd_set *sd_set,
				    const struct capture_config *config,
				    ntfs_volume **ntfs_vol_p)
{
	u32 attributes;
	int mrec_flags;
	u32 sd_size;
	int ret = 0;
	struct dentry *root;

	if (exclude_path(path, config, false)) {
		DEBUG("Excluding `%s' from capture", path);
		return 0;
	}

	DEBUG("Starting recursive capture at path = `%s'", path);
	mrec_flags = ni->mrec->flags;
 	attributes = ntfs_inode_get_attributes(ni);

	root = new_dentry(path_basename(path));
	if (!root)
		return WIMLIB_ERR_NOMEM;

	*root_p = root;
	root->creation_time    = le64_to_cpu(ni->creation_time);
	root->last_write_time  = le64_to_cpu(ni->last_data_change_time);
	root->last_access_time = le64_to_cpu(ni->last_access_time);
	root->security_id      = le32_to_cpu(ni->security_id);
	root->attributes       = le32_to_cpu(attributes);
	root->hard_link	 = ni->mft_no;
	root->resolved = true;

	if (attributes & FILE_ATTR_REPARSE_POINT) {
		DEBUG("Reparse point `%s'", path);
		/* Junction point, symbolic link, or other reparse point */
		ret = capture_ntfs_streams(root, ni, path, path_len,
					   lookup_table, ntfs_vol_p,
					   AT_REPARSE_POINT);
	} else if (mrec_flags & MFT_RECORD_IS_DIRECTORY) {
		DEBUG("Directory `%s'", path);

		/* Normal directory */
		s64 pos = 0;
		struct readdir_ctx ctx = {
			.parent       = root,
			.dir_ni       = ni,
			.path         = path,
			.path_len     = path_len,
			.lookup_table = lookup_table,
			.sd_set       = sd_set,
			.config       = config,
			.ntfs_vol_p   = ntfs_vol_p,
		};
		ret = ntfs_readdir(ni, &pos, &ctx, wim_ntfs_capture_filldir);
		if (ret != 0) {
			ERROR_WITH_ERRNO("ntfs_readdir()");
			ret = WIMLIB_ERR_NTFS_3G;
		}
	} else {
		DEBUG("Normal file `%s'", path);
		/* Normal file */
		ret = capture_ntfs_streams(root, ni, path, path_len,
					   lookup_table, ntfs_vol_p,
					   AT_DATA);
	}
	if (ret != 0)
		return ret;

	ret = ntfs_inode_get_security(ni,
				      OWNER_SECURITY_INFORMATION |
				      GROUP_SECURITY_INFORMATION |
				      DACL_SECURITY_INFORMATION  |
				      SACL_SECURITY_INFORMATION,
				      NULL, 0, &sd_size);
	u8 sd[sd_size];
	ret = ntfs_inode_get_security(ni,
				      OWNER_SECURITY_INFORMATION |
				      GROUP_SECURITY_INFORMATION |
				      DACL_SECURITY_INFORMATION  |
				      SACL_SECURITY_INFORMATION,
				      sd, sd_size, &sd_size);
	if (ret == 0) {
		ERROR_WITH_ERRNO("Failed to get security information from "
				 "`%s'", path);
		ret = WIMLIB_ERR_NTFS_3G;
	} else {
		if (ret > 0) {
			/*print_security_descriptor(sd, sd_size);*/
			root->security_id = sd_set_add_sd(sd_set, sd, sd_size);
			DEBUG("Added security ID = %u for `%s'",
			      root->security_id, path);
		} else { 
			root->security_id = -1;
			DEBUG("No security ID for `%s'", path);
		}
		ret = 0;
	}
	return ret;
}

static int build_dentry_tree_ntfs(struct dentry **root_p,
				  const char *device,
				  struct lookup_table *lookup_table,
				  struct wim_security_data *sd,
				  const struct capture_config *config,
				  int flags,
				  void *extra_arg)
{
	ntfs_volume *vol;
	ntfs_inode *root_ni;
	int ret = 0;
	struct sd_set sd_set;
	sd_set.sd = sd;
	sd_set.root = NULL;
	ntfs_volume **ntfs_vol_p = extra_arg;

	DEBUG("Mounting NTFS volume `%s' read-only", device);
	
	vol = ntfs_mount(device, MS_RDONLY);
	if (!vol) {
		ERROR_WITH_ERRNO("Failed to mount NTFS volume `%s' read-only",
				 device);
		return WIMLIB_ERR_NTFS_3G;
	}

	NVolClearShowSysFiles(vol);

	DEBUG("Opening root NTFS dentry");
	root_ni = ntfs_inode_open(vol, FILE_root);
	if (!root_ni) {
		ERROR_WITH_ERRNO("Failed to open root inode of NTFS volume "
				 "`%s'", device);
		ret = WIMLIB_ERR_NTFS_3G;
		goto out;
	}
	char path[4096];
	path[0] = '/';
	path[1] = '\0';
	ret = __build_dentry_tree_ntfs(root_p, root_ni, path, 1,
				       lookup_table, &sd_set, config,
				       ntfs_vol_p);
	ntfs_inode_close(root_ni);
	destroy_sd_set(&sd_set);

out:
	if (ret) {
		if (ntfs_umount(vol, FALSE) != 0) {
			ERROR_WITH_ERRNO("Failed to unmount NTFS volume `%s'",
					 device);
			if (ret == 0)
				ret = WIMLIB_ERR_NTFS_3G;
		}
	} else {
		*ntfs_vol_p = vol;
	}
	return ret;
}



WIMLIBAPI int wimlib_add_image_from_ntfs_volume(WIMStruct *w,
						const char *device,
						const char *name,
						const char *config_str,
						size_t config_len,
						int flags)
{
	if (flags & (WIMLIB_ADD_IMAGE_FLAG_DEREFERENCE)) {
		ERROR("Cannot dereference files when capturing directly from NTFS");
		return WIMLIB_ERR_INVALID_PARAM;
	}
	return do_add_image(w, device, name, config_str, config_len, flags,
			    build_dentry_tree_ntfs, &w->ntfs_vol);
}

#else /* WITH_NTFS_3G */
WIMLIBAPI int wimlib_add_image_from_ntfs_volume(WIMStruct *w,
						const char *device,
						const char *name,
						const char *description,
						const char *flags_element,
						int flags,
						const char *config_str,
						size_t config_len)
{
	ERROR("wimlib was compiled without support for NTFS-3g, so");
	ERROR("we cannot capture a WIM image directly from a NTFS volume");
	return WIMLIB_ERR_UNSUPPORTED;
}
#endif /* WITH_NTFS_3G */