dir.c

上一个上传的有问题,这个是好的。visopsys包括系统内核和GUI的全部SOURCE code ,还包括一些基本的docs文档。里面src子目录对应所有SOURCE code.对于想研究操作系统的朋

/**
 * dir.c - Directory handling code. Part of the Linux-NTFS project.
 *
 * Copyright (c) 2002-2005 Anton Altaparmakov
 * Copyright (c) 2005-2006 Yura Pakhuchiy
 * Copyright (c) 2004-2005 Richard Russon
 *
 * This program/include file 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/include file 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 (in the main directory of the Linux-NTFS
 * distribution in the file COPYING); if not, write to the Free Software
 * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Modified 01/2007 by Andy McLaughlin for Visopsys port.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#ifdef HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif

#ifdef HAVE_SYS_SYSMACROS_H
#include <sys/sysmacros.h>
#endif

#include "types.h"
#include "debug.h"
#include "attrib.h"
#include "inode.h"
#include "dir.h"
#include "volume.h"
#include "mft.h"
#include "index.h"
#include "ntfstime.h"
#include "lcnalloc.h"
#include "logging.h"

/*
 * The little endian Unicode strings "$I30", "$SII", "$SDH", "$O"
 *  and "$Q" as global constants.
 */
ntfschar NTFS_INDEX_I30[5] = { const_cpu_to_le16('$'), const_cpu_to_le16('I'),
		const_cpu_to_le16('3'), const_cpu_to_le16('0'),
		const_cpu_to_le16('\0') };
ntfschar NTFS_INDEX_SII[5] = { const_cpu_to_le16('$'), const_cpu_to_le16('S'),
		const_cpu_to_le16('I'), const_cpu_to_le16('I'),
		const_cpu_to_le16('\0') };
ntfschar NTFS_INDEX_SDH[5] = { const_cpu_to_le16('$'), const_cpu_to_le16('S'),
		const_cpu_to_le16('D'), const_cpu_to_le16('H'),
		const_cpu_to_le16('\0') };
ntfschar NTFS_INDEX_O[3] = { const_cpu_to_le16('$'), const_cpu_to_le16('O'),
		const_cpu_to_le16('\0') };
ntfschar NTFS_INDEX_Q[3] = { const_cpu_to_le16('$'), const_cpu_to_le16('Q'),
		const_cpu_to_le16('\0') };
ntfschar NTFS_INDEX_R[3] = { const_cpu_to_le16('$'), const_cpu_to_le16('R'),
		const_cpu_to_le16('\0') };

/**
 * ntfs_inode_lookup_by_name - find an inode in a directory given its name
 * @dir_ni:	ntfs inode of the directory in which to search for the name
 * @uname:	Unicode name for which to search in the directory
 * @uname_len:	length of the name @uname in Unicode characters
 *
 * Look for an inode with name @uname in the directory with inode @dir_ni.
 * ntfs_inode_lookup_by_name() walks the contents of the directory looking for
 * the Unicode name. If the name is found in the directory, the corresponding
 * inode number (>= 0) is returned as a mft reference in cpu format, i.e. it
 * is a 64-bit number containing the sequence number.
 *
 * On error, return -1 with errno set to the error code. If the inode is is not
 * found errno is ENOENT.
 *
 * Note, @uname_len does not include the (optional) terminating NULL character.
 *
 * Note, we look for a case sensitive match first but we also look for a case
 * insensitive match at the same time. If we find a case insensitive match, we
 * save that for the case that we don't find an exact match, where we return
 * the mft reference of the case insensitive match.
 *
 * If the volume is mounted with the case sensitive flag set, then we only
 * allow exact matches.
 */
u64 ntfs_inode_lookup_by_name(ntfs_inode *dir_ni, const ntfschar *uname,
		const int uname_len)
{
	VCN vcn;
	u64 mref = 0;
	s64 br;
	ntfs_volume *vol = dir_ni->vol;
	ntfs_attr_search_ctx *ctx;
	INDEX_ROOT *ir;
	INDEX_ENTRY *ie;
	INDEX_ALLOCATION *ia;
	u8 *index_end;
	ntfs_attr *ia_na;
	int eo, rc;
	u32 index_block_size, index_vcn_size;
	u8 index_vcn_size_bits;

	if (!dir_ni || !dir_ni->mrec || !uname || uname_len <= 0) {
		errno = EINVAL;
		return -1;
	}

	ctx = ntfs_attr_get_search_ctx(dir_ni, NULL);
	if (!ctx)
		return -1;

	/* Find the index root attribute in the mft record. */
	if (ntfs_attr_lookup(AT_INDEX_ROOT, NTFS_INDEX_I30, 4, CASE_SENSITIVE, 0, NULL,
			0, ctx)) {
		ntfs_log_perror("Index root attribute missing in directory inode "
				"0x%llx", (unsigned long long)dir_ni->mft_no);
		goto put_err_out;
	}
	/* Get to the index root value. */
	ir = (INDEX_ROOT*)((u8*)ctx->attr +
			le16_to_cpu(ctx->attr->value_offset));
	index_block_size = le32_to_cpu(ir->index_block_size);
	if (index_block_size < NTFS_BLOCK_SIZE ||
			index_block_size & (index_block_size - 1)) {
		ntfs_log_debug("Index block size %u is invalid.\n",
				(unsigned)index_block_size);
		goto put_err_out;
	}
	index_end = (u8*)&ir->index + le32_to_cpu(ir->index.index_length);
	/* The first index entry. */
	ie = (INDEX_ENTRY*)((u8*)&ir->index +
			le32_to_cpu(ir->index.entries_offset));
	/*
	 * Loop until we exceed valid memory (corruption case) or until we
	 * reach the last entry.
	 */
	for (;; ie = (INDEX_ENTRY*)((u8*)ie + le16_to_cpu(ie->length))) {
		/* Bounds checks. */
		if ((u8*)ie < (u8*)ctx->mrec || (u8*)ie +
				sizeof(INDEX_ENTRY_HEADER) > index_end ||
				(u8*)ie + le16_to_cpu(ie->key_length) >
				index_end)
			goto put_err_out;
		/*
		 * The last entry cannot contain a name. It can however contain
		 * a pointer to a child node in the B+tree so we just break out.
		 */
		if (ie->flags & INDEX_ENTRY_END)
			break;
		/*
		 * We perform a case sensitive comparison and if that matches
		 * we are done and return the mft reference of the inode (i.e.
		 * the inode number together with the sequence number for
		 * consistency checking). We convert it to cpu format before
		 * returning.
		 */
		if (ntfs_names_are_equal(uname, uname_len,
				(ntfschar*)&ie->key.file_name.file_name,
				ie->key.file_name.file_name_length,
				CASE_SENSITIVE, vol->upcase, vol->upcase_len)) {
found_it:
			/*
			 * We have a perfect match, so we don't need to care
			 * about having matched imperfectly before.
			 */
			mref = le64_to_cpu(ie->indexed_file);
			ntfs_attr_put_search_ctx(ctx);
			return mref;
		}
		/*
		 * For a case insensitive mount, we also perform a case
		 * insensitive comparison (provided the file name is not in the
		 * POSIX namespace). If the comparison matches, we cache the
		 * mft reference in mref.
		 */
		if (!NVolCaseSensitive(vol) &&
				ie->key.file_name.file_name_type &&
				ntfs_names_are_equal(uname, uname_len,
				(ntfschar*)&ie->key.file_name.file_name,
				ie->key.file_name.file_name_length,
				IGNORE_CASE, vol->upcase, vol->upcase_len)) {
			/* Only one case insensitive matching name allowed. */
			if (mref) {
				ntfs_log_error("Found already cached mft "
						"reference in phase 1. Please "
						"run chkdsk and if that doesn't"
						" find any errors please report"
						" you saw this message to %s\n",
						NTFS_DEV_LIST);
				goto put_err_out;
			}
			mref = le64_to_cpu(ie->indexed_file);
		}
		/*
		 * Not a perfect match, need to do full blown collation so we
		 * know which way in the B+tree we have to go.
		 */
		rc = ntfs_names_collate(uname, uname_len,
				(ntfschar*)&ie->key.file_name.file_name,
				ie->key.file_name.file_name_length, 1,
				IGNORE_CASE, vol->upcase, vol->upcase_len);
		/*
		 * If uname collates before the name of the current entry, there
		 * is definitely no such name in this index but we might need to
		 * descend into the B+tree so we just break out of the loop.
		 */
		if (rc == -1)
			break;
		/* The names are not equal, continue the search. */
		if (rc)
			continue;
		/*
		 * Names match with case insensitive comparison, now try the
		 * case sensitive comparison, which is required for proper
		 * collation.
		 */
		rc = ntfs_names_collate(uname, uname_len,
				(ntfschar*)&ie->key.file_name.file_name,
				ie->key.file_name.file_name_length, 1,
				CASE_SENSITIVE, vol->upcase, vol->upcase_len);
		if (rc == -1)
			break;
		if (rc)
			continue;
		/*
		 * Perfect match, this will never happen as the
		 * ntfs_are_names_equal() call will have gotten a match but we
		 * still treat it correctly.
		 */
		goto found_it;
	}
	/*
	 * We have finished with this index without success. Check for the
	 * presence of a child node and if not present return error code
	 * ENOENT, unless we have got the mft reference of a matching name
	 * cached in mref in which case return mref.
	 */
	if (!(ie->flags & INDEX_ENTRY_NODE)) {
		ntfs_attr_put_search_ctx(ctx);
		if (mref)
			return mref;
		ntfs_log_debug("Entry not found.\n");
		errno = ENOENT;
		return -1;
	} /* Child node present, descend into it. */

	/* Open the index allocation attribute. */
	ia_na = ntfs_attr_open(dir_ni, AT_INDEX_ALLOCATION, NTFS_INDEX_I30, 4);
	if (!ia_na) {
		ntfs_log_perror("Failed to open index allocation attribute. Directory "
				"inode 0x%llx is corrupt or driver bug",
				(unsigned long long)dir_ni->mft_no);
		goto put_err_out;
	}

	/* Allocate a buffer for the current index block. */
	ia = (INDEX_ALLOCATION*)malloc(index_block_size);
	if (!ia) {
		ntfs_log_perror("Failed to allocate buffer for index block");
		ntfs_attr_close(ia_na);
		goto put_err_out;
	}

	/* Determine the size of a vcn in the directory index. */
	if (vol->cluster_size <= index_block_size) {
		index_vcn_size = vol->cluster_size;
		index_vcn_size_bits = vol->cluster_size_bits;
	} else {
		index_vcn_size = vol->sector_size;
		index_vcn_size_bits = vol->sector_size_bits;
	}

	/* Get the starting vcn of the index_block holding the child node. */
	vcn = sle64_to_cpup((u8*)ie + le16_to_cpu(ie->length) - 8);

descend_into_child_node:

	/* Read the index block starting at vcn. */
	br = ntfs_attr_mst_pread(ia_na, vcn << index_vcn_size_bits, 1,
			index_block_size, ia);
	if (br != 1) {
		if (br != -1)
			errno = EIO;
		ntfs_log_perror("Failed to read vcn 0x%llx", vcn);
		goto close_err_out;
	}

	if (sle64_to_cpu(ia->index_block_vcn) != vcn) {
		ntfs_log_debug("Actual VCN (0x%llx) of index buffer is different "
				"from expected VCN (0x%llx).\n",
				(long long)sle64_to_cpu(ia->index_block_vcn),
				(long long)vcn);
		errno = EIO;
		goto close_err_out;
	}
	if (le32_to_cpu(ia->index.allocated_size) + 0x18 != index_block_size) {
		ntfs_log_debug("Index buffer (VCN 0x%llx) of directory inode 0x%llx "
				"has a size (%u) differing from the directory "
				"specified size (%u).\n", (long long)vcn,
				(unsigned long long)dir_ni->mft_no,
				(unsigned) le32_to_cpu(ia->index.allocated_size) + 0x18,
				(unsigned)index_block_size);
		errno = EIO;
		goto close_err_out;
	}
	index_end = (u8*)&ia->index + le32_to_cpu(ia->index.index_length);
	if (index_end > (u8*)ia + index_block_size) {
		ntfs_log_debug("Size of index buffer (VCN 0x%llx) of directory inode "
				"0x%llx exceeds maximum size.\n",
				(long long)vcn, (unsigned long long)dir_ni->mft_no);
		errno = EIO;
		goto close_err_out;
	}

	/* The first index entry. */
	ie = (INDEX_ENTRY*)((u8*)&ia->index +
			le32_to_cpu(ia->index.entries_offset));
	/*
	 * Iterate similar to above big loop but applied to index buffer, thus
	 * loop until we exceed valid memory (corruption case) or until we
	 * reach the last entry.
	 */
	for (;; ie = (INDEX_ENTRY*)((u8*)ie + le16_to_cpu(ie->length))) {
		/* Bounds check. */
		if ((u8*)ie < (u8*)ia || (u8*)ie +
				sizeof(INDEX_ENTRY_HEADER) > index_end ||
				(u8*)ie + le16_to_cpu(ie->key_length) >
				index_end) {
			ntfs_log_debug("Index entry out of bounds in directory "
					"inode 0x%llx.\n",
					(unsigned long long)dir_ni->mft_no);
			errno = EIO;
			goto close_err_out;
		}
		/*
		 * The last entry cannot contain a name. It can however contain
		 * a pointer to a child node in the B+tree so we just break out.
		 */
		if (ie->flags & INDEX_ENTRY_END)
			break;
		/*
		 * We perform a case sensitive comparison and if that matches
		 * we are done and return the mft reference of the inode (i.e.
		 * the inode number together with the sequence number for
		 * consistency checking). We convert it to cpu format before
		 * returning.
		 */
		if (ntfs_names_are_equal(uname, uname_len,
				(ntfschar*)&ie->key.file_name.file_name,
				ie->key.file_name.file_name_length,
				CASE_SENSITIVE, vol->upcase, vol->upcase_len)) {
found_it2:
			/*
			 * We have a perfect match, so we don't need to care
			 * about having matched imperfectly before.
			 */
			mref = le64_to_cpu(ie->indexed_file);
			free(ia);
			ntfs_attr_close(ia_na);
			ntfs_attr_put_search_ctx(ctx);
			return mref;
		}
		/*
		 * For a case insensitive mount, we also perform a case
		 * insensitive comparison (provided the file name is not in the
		 * POSIX namespace). If the comparison matches, we cache the
		 * mft reference in mref.
		 */
		if (!NVolCaseSensitive(vol) &&
				ie->key.file_name.file_name_type &&
				ntfs_names_are_equal(uname, uname_len,
				(ntfschar*)&ie->key.file_name.file_name,
				ie->key.file_name.file_name_length,
				IGNORE_CASE, vol->upcase, vol->upcase_len)) {
			/* Only one case insensitive matching name allowed. */
			if (mref) {
				ntfs_log_error("Found already cached mft "
						"reference in phase 2. Please "
						"run chkdsk and if that doesn't"
						" find any errors please report"
						" you saw this message to %s\n",
						NTFS_DEV_LIST);
				goto close_err_out;
			}
			mref = le64_to_cpu(ie->indexed_file);
		}
		/*
		 * Not a perfect match, need to do full blown collation so we
		 * know which way in the B+tree we have to go.
		 */
		rc = ntfs_names_collate(uname, uname_len,
				(ntfschar*)&ie->key.file_name.file_name,
				ie->key.file_name.file_name_length, 1,
				IGNORE_CASE, vol->upcase, vol->upcase_len);
		/*
		 * If uname collates before the name of the current entry, there
		 * is definitely no such name in this index but we might need to
		 * descend into the B+tree so we just break out of the loop.
		 */
		if (rc == -1)
			break;
		/* The names are not equal, continue the search. */
		if (rc)
			continue;
		/*
		 * Names match with case insensitive comparison, now try the
		 * case sensitive comparison, which is required for proper
		 * collation.
		 */
		rc = ntfs_names_collate(uname, uname_len,
				(ntfschar*)&ie->key.file_name.file_name,
				ie->key.file_name.file_name_length, 1,
				CASE_SENSITIVE, vol->upcase, vol->upcase_len);
		if (rc == -1)
			break;
		if (rc)
			continue;
		/*
		 * Perfect match, this will never happen as the
		 * ntfs_are_names_equal() call will have gotten a match but we
		 * still treat it correctly.
		 */
		goto found_it2;
	}
	/*
	 * We have finished with this index buffer without success. Check for
	 * the presence of a child node.
	 */
	if (ie->flags & INDEX_ENTRY_NODE) {
		if ((ia->index.flags & NODE_MASK) == LEAF_NODE) {
			ntfs_log_debug("Index entry with child node found in a leaf "
					"node in directory inode 0x%llx.\n",
					(unsigned long long)dir_ni->mft_no);
			errno = EIO;
			goto close_err_out;
		}
		/* Child node present, descend into it. */
		vcn = sle64_to_cpup((u8*)ie + le16_to_cpu(ie->length) - 8);
		if (vcn >= 0)
			goto descend_into_child_node;
		ntfs_log_debug("Negative child node vcn in directory inode "
				"0x%llx.\n", (unsigned long long)dir_ni->mft_no);
		errno = EIO;
		goto close_err_out;
	}
	free(ia);
	ntfs_attr_close(ia_na);
	ntfs_attr_put_search_ctx(ctx);
	/*
	 * No child node present, return error code ENOENT, unless we have got
	 * the mft reference of a matching name cached in mref in which case
	 * return mref.
	 */
	if (mref)
		return mref;
	ntfs_log_debug("Entry not found.\n");
	errno = ENOENT;
	return -1;
put_err_out:
	eo = EIO;
	ntfs_log_debug("Corrupt directory. Aborting lookup.\n");
eo_put_err_out:
	ntfs_attr_put_search_ctx(ctx);
	errno = eo;
	return -1;
close_err_out:
	eo = errno;
	free(ia);
	ntfs_attr_close(ia_na);
	goto eo_put_err_out;
}

#ifndef __VISOPSYS__
/**
 * ntfs_pathname_to_inode - Find the inode which represents the given pathname
 * @vol:       An ntfs volume obtained from ntfs_mount
 * @parent:    A directory inode to begin the search (may be NULL)
 * @pathname:  Pathname to be located
 *
 * Take an ASCII pathname and find the inode that represents it.  The function
 * splits the path and then descends the directory tree.  If @parent is NULL,
 * then the root directory '.' will be used as the base for the search.
 *
 * Return:  inode  Success, the pathname was valid
 *	    NULL   Error, the pathname was invalid, or some other error occurred
 */
ntfs_inode *ntfs_pathname_to_inode(ntfs_volume *vol, ntfs_inode *parent,
		const char *pathname)
{
	u64 inum;
	int len, err = 0;
	char *p, *q;
	ntfs_inode *ni;
	ntfs_inode *result = NULL;
	ntfschar *unicode = NULL;
	char *ascii = NULL;

	if (!vol || !pathname) {
		errno = EINVAL;
		return NULL;
	}

	if (parent) {
		ni = parent;
	} else {
		ni = ntfs_inode_open(vol, FILE_root);
		if (!ni) {
			ntfs_log_debug("Couldn't open the inode of the root "
					"directory.\n");
			err = EIO;
			goto close;
		}
	}

	unicode = calloc(1, MAX_PATH);