/*
   * Copyright (c) 2000-2005 Silicon Graphics, Inc.
   * Copyright (c) 2013 Red Hat, Inc.
   * All Rights Reserved.
   *
   * 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.
   *
   * This program is distributed in the hope that it would 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 the Free Software Foundation,
   * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
   */
  #include "xfs.h"
  #include "xfs_fs.h"

  #include "xfs_format.h"

  #include "xfs_log_format.h"
  #include "xfs_trans_resv.h"

  #include "xfs_bit.h"

  #include "xfs_mount.h"

  #include "xfs_da_format.h"

  #include "xfs_da_btree.h"

  #include "xfs_inode.h"

  #include "xfs_trans.h"

  #include "xfs_inode_item.h"
  #include "xfs_bmap.h"
  #include "xfs_attr.h"

  #include "xfs_attr_sf.h"
  #include "xfs_attr_remote.h"

  #include "xfs_attr_leaf.h"
  #include "xfs_error.h"
  #include "xfs_trace.h"
  #include "xfs_buf_item.h"
  #include "xfs_cksum.h"

  #include "xfs_dir2.h"

  
  STATIC int
  xfs_attr_shortform_compare(const void *a, const void *b)
  {
  	xfs_attr_sf_sort_t *sa, *sb;
  
  	sa = (xfs_attr_sf_sort_t *)a;
  	sb = (xfs_attr_sf_sort_t *)b;
  	if (sa->hash < sb->hash) {

  		return -1;

  	} else if (sa->hash > sb->hash) {

  		return 1;

  	} else {

  		return sa->entno - sb->entno;

  	}
  }
  
  #define XFS_ISRESET_CURSOR(cursor) \
  	(!((cursor)->initted) && !((cursor)->hashval) && \
  	 !((cursor)->blkno) && !((cursor)->offset))
  /*
   * Copy out entries of shortform attribute lists for attr_list().
   * Shortform attribute lists are not stored in hashval sorted order.
   * If the output buffer is not large enough to hold them all, then we
   * we have to calculate each entries' hashvalue and sort them before
   * we can begin returning them to the user.
   */

  static int

  xfs_attr_shortform_list(xfs_attr_list_context_t *context)
  {
  	attrlist_cursor_kern_t *cursor;
  	xfs_attr_sf_sort_t *sbuf, *sbp;
  	xfs_attr_shortform_t *sf;
  	xfs_attr_sf_entry_t *sfe;
  	xfs_inode_t *dp;
  	int sbsize, nsbuf, count, i;
  	int error;
  
  	ASSERT(context != NULL);
  	dp = context->dp;
  	ASSERT(dp != NULL);
  	ASSERT(dp->i_afp != NULL);
  	sf = (xfs_attr_shortform_t *)dp->i_afp->if_u1.if_data;
  	ASSERT(sf != NULL);
  	if (!sf->hdr.count)

  		return 0;

  	cursor = context->cursor;
  	ASSERT(cursor != NULL);
  
  	trace_xfs_attr_list_sf(context);
  
  	/*
  	 * If the buffer is large enough and the cursor is at the start,
  	 * do not bother with sorting since we will return everything in
  	 * one buffer and another call using the cursor won't need to be
  	 * made.
  	 * Note the generous fudge factor of 16 overhead bytes per entry.
  	 * If bufsize is zero then put_listent must be a search function
  	 * and can just scan through what we have.
  	 */
  	if (context->bufsize == 0 ||
  	    (XFS_ISRESET_CURSOR(cursor) &&
               (dp->i_afp->if_bytes + sf->hdr.count * 16) < context->bufsize)) {
  		for (i = 0, sfe = &sf->list[0]; i < sf->hdr.count; i++) {
  			error = context->put_listent(context,
  					   sfe->flags,
  					   sfe->nameval,
  					   (int)sfe->namelen,

  					   (int)sfe->valuelen);

  			if (error)
  				return error;

  			/*
  			 * Either search callback finished early or
  			 * didn't fit it all in the buffer after all.
  			 */
  			if (context->seen_enough)
  				break;

  			sfe = XFS_ATTR_SF_NEXTENTRY(sfe);
  		}
  		trace_xfs_attr_list_sf_all(context);

  		return 0;

  	}
  
  	/* do no more for a search callback */
  	if (context->bufsize == 0)
  		return 0;
  
  	/*
  	 * It didn't all fit, so we have to sort everything on hashval.
  	 */
  	sbsize = sf->hdr.count * sizeof(*sbuf);
  	sbp = sbuf = kmem_alloc(sbsize, KM_SLEEP | KM_NOFS);
  
  	/*
  	 * Scan the attribute list for the rest of the entries, storing
  	 * the relevant info from only those that match into a buffer.
  	 */
  	nsbuf = 0;
  	for (i = 0, sfe = &sf->list[0]; i < sf->hdr.count; i++) {
  		if (unlikely(
  		    ((char *)sfe < (char *)sf) ||
  		    ((char *)sfe >= ((char *)sf + dp->i_afp->if_bytes)))) {
  			XFS_CORRUPTION_ERROR("xfs_attr_shortform_list",
  					     XFS_ERRLEVEL_LOW,
  					     context->dp->i_mount, sfe);
  			kmem_free(sbuf);

  			return -EFSCORRUPTED;

  		}
  
  		sbp->entno = i;
  		sbp->hash = xfs_da_hashname(sfe->nameval, sfe->namelen);
  		sbp->name = sfe->nameval;
  		sbp->namelen = sfe->namelen;
  		/* These are bytes, and both on-disk, don't endian-flip */
  		sbp->valuelen = sfe->valuelen;
  		sbp->flags = sfe->flags;
  		sfe = XFS_ATTR_SF_NEXTENTRY(sfe);
  		sbp++;
  		nsbuf++;
  	}
  
  	/*
  	 * Sort the entries on hash then entno.
  	 */
  	xfs_sort(sbuf, nsbuf, sizeof(*sbuf), xfs_attr_shortform_compare);
  
  	/*
  	 * Re-find our place IN THE SORTED LIST.
  	 */
  	count = 0;
  	cursor->initted = 1;
  	cursor->blkno = 0;
  	for (sbp = sbuf, i = 0; i < nsbuf; i++, sbp++) {
  		if (sbp->hash == cursor->hashval) {
  			if (cursor->offset == count) {
  				break;
  			}
  			count++;
  		} else if (sbp->hash > cursor->hashval) {
  			break;
  		}
  	}
  	if (i == nsbuf) {
  		kmem_free(sbuf);

  		return 0;

  	}
  
  	/*
  	 * Loop putting entries into the user buffer.
  	 */
  	for ( ; i < nsbuf; i++, sbp++) {
  		if (cursor->hashval != sbp->hash) {
  			cursor->hashval = sbp->hash;
  			cursor->offset = 0;
  		}
  		error = context->put_listent(context,
  					sbp->flags,
  					sbp->name,
  					sbp->namelen,

  					sbp->valuelen);

  		if (error) {
  			kmem_free(sbuf);

  			return error;

  		}

  		if (context->seen_enough)
  			break;
  		cursor->offset++;
  	}
  
  	kmem_free(sbuf);

  	return 0;

  }
  
  STATIC int
  xfs_attr_node_list(xfs_attr_list_context_t *context)
  {
  	attrlist_cursor_kern_t *cursor;
  	xfs_attr_leafblock_t *leaf;
  	xfs_da_intnode_t *node;
  	struct xfs_attr3_icleaf_hdr leafhdr;
  	struct xfs_da3_icnode_hdr nodehdr;
  	struct xfs_da_node_entry *btree;
  	int error, i;
  	struct xfs_buf *bp;

  	struct xfs_inode	*dp = context->dp;

  	struct xfs_mount	*mp = dp->i_mount;

  
  	trace_xfs_attr_node_list(context);
  
  	cursor = context->cursor;
  	cursor->initted = 1;
  
  	/*
  	 * Do all sorts of validation on the passed-in cursor structure.
  	 * If anything is amiss, ignore the cursor and look up the hashval
  	 * starting from the btree root.
  	 */
  	bp = NULL;
  	if (cursor->blkno > 0) {

  		error = xfs_da3_node_read(NULL, dp, cursor->blkno, -1,

  					      &bp, XFS_ATTR_FORK);

  		if ((error != 0) && (error != -EFSCORRUPTED))

  			return error;

  		if (bp) {
  			struct xfs_attr_leaf_entry *entries;
  
  			node = bp->b_addr;
  			switch (be16_to_cpu(node->hdr.info.magic)) {
  			case XFS_DA_NODE_MAGIC:
  			case XFS_DA3_NODE_MAGIC:
  				trace_xfs_attr_list_wrong_blk(context);
  				xfs_trans_brelse(NULL, bp);
  				bp = NULL;
  				break;
  			case XFS_ATTR_LEAF_MAGIC:
  			case XFS_ATTR3_LEAF_MAGIC:
  				leaf = bp->b_addr;

  				xfs_attr3_leaf_hdr_from_disk(mp->m_attr_geo,
  							     &leafhdr, leaf);

  				entries = xfs_attr3_leaf_entryp(leaf);
  				if (cursor->hashval > be32_to_cpu(
  						entries[leafhdr.count - 1].hashval)) {
  					trace_xfs_attr_list_wrong_blk(context);
  					xfs_trans_brelse(NULL, bp);
  					bp = NULL;
  				} else if (cursor->hashval <= be32_to_cpu(
  						entries[0].hashval)) {
  					trace_xfs_attr_list_wrong_blk(context);
  					xfs_trans_brelse(NULL, bp);
  					bp = NULL;
  				}
  				break;
  			default:
  				trace_xfs_attr_list_wrong_blk(context);
  				xfs_trans_brelse(NULL, bp);
  				bp = NULL;
  			}
  		}
  	}
  
  	/*
  	 * We did not find what we expected given the cursor's contents,
  	 * so we start from the top and work down based on the hash value.
  	 * Note that start of node block is same as start of leaf block.
  	 */
  	if (bp == NULL) {
  		cursor->blkno = 0;
  		for (;;) {
  			__uint16_t magic;

  			error = xfs_da3_node_read(NULL, dp,

  						      cursor->blkno, -1, &bp,
  						      XFS_ATTR_FORK);
  			if (error)

  				return error;

  			node = bp->b_addr;
  			magic = be16_to_cpu(node->hdr.info.magic);
  			if (magic == XFS_ATTR_LEAF_MAGIC ||
  			    magic == XFS_ATTR3_LEAF_MAGIC)
  				break;
  			if (magic != XFS_DA_NODE_MAGIC &&
  			    magic != XFS_DA3_NODE_MAGIC) {
  				XFS_CORRUPTION_ERROR("xfs_attr_node_list(3)",
  						     XFS_ERRLEVEL_LOW,
  						     context->dp->i_mount,
  						     node);
  				xfs_trans_brelse(NULL, bp);

  				return -EFSCORRUPTED;

  			}

  			dp->d_ops->node_hdr_from_disk(&nodehdr, node);

  			btree = dp->d_ops->node_tree_p(node);

  			for (i = 0; i < nodehdr.count; btree++, i++) {
  				if (cursor->hashval
  						<= be32_to_cpu(btree->hashval)) {
  					cursor->blkno = be32_to_cpu(btree->before);
  					trace_xfs_attr_list_node_descend(context,
  									 btree);
  					break;
  				}
  			}
  			if (i == nodehdr.count) {
  				xfs_trans_brelse(NULL, bp);
  				return 0;
  			}
  			xfs_trans_brelse(NULL, bp);
  		}
  	}
  	ASSERT(bp != NULL);
  
  	/*
  	 * Roll upward through the blocks, processing each leaf block in
  	 * order.  As long as there is space in the result buffer, keep
  	 * adding the information.
  	 */
  	for (;;) {
  		leaf = bp->b_addr;
  		error = xfs_attr3_leaf_list_int(bp, context);
  		if (error) {
  			xfs_trans_brelse(NULL, bp);
  			return error;
  		}

  		xfs_attr3_leaf_hdr_from_disk(mp->m_attr_geo, &leafhdr, leaf);

  		if (context->seen_enough || leafhdr.forw == 0)
  			break;
  		cursor->blkno = leafhdr.forw;
  		xfs_trans_brelse(NULL, bp);

  		error = xfs_attr3_leaf_read(NULL, dp, cursor->blkno, -1, &bp);

  		if (error)
  			return error;
  	}
  	xfs_trans_brelse(NULL, bp);
  	return 0;
  }
  
  /*
   * Copy out attribute list entries for attr_list(), for leaf attribute lists.
   */
  int
  xfs_attr3_leaf_list_int(
  	struct xfs_buf			*bp,
  	struct xfs_attr_list_context	*context)
  {
  	struct attrlist_cursor_kern	*cursor;
  	struct xfs_attr_leafblock	*leaf;
  	struct xfs_attr3_icleaf_hdr	ichdr;
  	struct xfs_attr_leaf_entry	*entries;
  	struct xfs_attr_leaf_entry	*entry;
  	int				retval;
  	int				i;

  	struct xfs_mount		*mp = context->dp->i_mount;

  
  	trace_xfs_attr_list_leaf(context);
  
  	leaf = bp->b_addr;

  	xfs_attr3_leaf_hdr_from_disk(mp->m_attr_geo, &ichdr, leaf);

  	entries = xfs_attr3_leaf_entryp(leaf);
  
  	cursor = context->cursor;
  	cursor->initted = 1;
  
  	/*
  	 * Re-find our place in the leaf block if this is a new syscall.
  	 */
  	if (context->resynch) {
  		entry = &entries[0];
  		for (i = 0; i < ichdr.count; entry++, i++) {
  			if (be32_to_cpu(entry->hashval) == cursor->hashval) {
  				if (cursor->offset == context->dupcnt) {
  					context->dupcnt = 0;
  					break;
  				}
  				context->dupcnt++;
  			} else if (be32_to_cpu(entry->hashval) >
  					cursor->hashval) {
  				context->dupcnt = 0;
  				break;
  			}
  		}
  		if (i == ichdr.count) {
  			trace_xfs_attr_list_notfound(context);
  			return 0;
  		}
  	} else {
  		entry = &entries[0];
  		i = 0;
  	}
  	context->resynch = 0;
  
  	/*
  	 * We have found our place, start copying out the new attributes.
  	 */
  	retval = 0;
  	for (; i < ichdr.count; entry++, i++) {

  		char *name;
  		int namelen, valuelen;

  		if (be32_to_cpu(entry->hashval) != cursor->hashval) {
  			cursor->hashval = be32_to_cpu(entry->hashval);
  			cursor->offset = 0;
  		}
  
  		if (entry->flags & XFS_ATTR_INCOMPLETE)
  			continue;		/* skip incomplete entries */
  
  		if (entry->flags & XFS_ATTR_LOCAL) {

  			xfs_attr_leaf_name_local_t *name_loc;

  			name_loc = xfs_attr3_leaf_name_local(leaf, i);
  			name = name_loc->nameval;
  			namelen = name_loc->namelen;
  			valuelen = be16_to_cpu(name_loc->valuelen);
  		} else {
  			xfs_attr_leaf_name_remote_t *name_rmt;

  			name_rmt = xfs_attr3_leaf_name_remote(leaf, i);
  			name = name_rmt->name;
  			namelen = name_rmt->namelen;
  			valuelen = be32_to_cpu(name_rmt->valuelen);

  		}

  
  		retval = context->put_listent(context, entry->flags,
  					      name, namelen, valuelen);

  		if (retval)
  			break;

  		if (context->seen_enough)
  			break;
  		cursor->offset++;
  	}
  	trace_xfs_attr_list_leaf_end(context);
  	return retval;
  }
  
  /*
   * Copy out attribute entries for attr_list(), for leaf attribute lists.
   */
  STATIC int
  xfs_attr_leaf_list(xfs_attr_list_context_t *context)
  {
  	int error;
  	struct xfs_buf *bp;
  
  	trace_xfs_attr_leaf_list(context);
  
  	context->cursor->blkno = 0;
  	error = xfs_attr3_leaf_read(NULL, context->dp, 0, -1, &bp);
  	if (error)

  		return error;

  
  	error = xfs_attr3_leaf_list_int(bp, context);
  	xfs_trans_brelse(NULL, bp);

  	return error;

  }
  
  int
  xfs_attr_list_int(
  	xfs_attr_list_context_t *context)
  {
  	int error;
  	xfs_inode_t *dp = context->dp;

  	uint		lock_mode;

  	XFS_STATS_INC(dp->i_mount, xs_attr_list);

  
  	if (XFS_FORCED_SHUTDOWN(dp->i_mount))

  		return -EIO;

  	/*
  	 * Decide on what work routines to call based on the inode size.
  	 */

  	lock_mode = xfs_ilock_attr_map_shared(dp);

  	if (!xfs_inode_hasattr(dp)) {
  		error = 0;
  	} else if (dp->i_d.di_aformat == XFS_DINODE_FMT_LOCAL) {
  		error = xfs_attr_shortform_list(context);
  	} else if (xfs_bmap_one_block(dp, XFS_ATTR_FORK)) {
  		error = xfs_attr_leaf_list(context);
  	} else {
  		error = xfs_attr_node_list(context);
  	}

  	xfs_iunlock(dp, lock_mode);

  	return error;
  }
  
  #define	ATTR_ENTBASESIZE		/* minimum bytes used by an attr */ \
  	(((struct attrlist_ent *) 0)->a_name - (char *) 0)
  #define	ATTR_ENTSIZE(namelen)		/* actual bytes used by an attr */ \
  	((ATTR_ENTBASESIZE + (namelen) + 1 + sizeof(u_int32_t)-1) \
  	 & ~(sizeof(u_int32_t)-1))
  
  /*
   * Format an attribute and copy it out to the user's buffer.
   * Take care to check values and protect against them changing later,
   * we may be reading them directly out of a user buffer.
   */
  STATIC int
  xfs_attr_put_listent(
  	xfs_attr_list_context_t *context,
  	int		flags,
  	unsigned char	*name,
  	int		namelen,

  	int		valuelen)

  {
  	struct attrlist *alist = (struct attrlist *)context->alist;
  	attrlist_ent_t *aep;
  	int arraytop;
  
  	ASSERT(!(context->flags & ATTR_KERNOVAL));
  	ASSERT(context->count >= 0);
  	ASSERT(context->count < (ATTR_MAX_VALUELEN/8));
  	ASSERT(context->firstu >= sizeof(*alist));
  	ASSERT(context->firstu <= context->bufsize);
  
  	/*
  	 * Only list entries in the right namespace.
  	 */
  	if (((context->flags & ATTR_SECURE) == 0) !=
  	    ((flags & XFS_ATTR_SECURE) == 0))
  		return 0;
  	if (((context->flags & ATTR_ROOT) == 0) !=
  	    ((flags & XFS_ATTR_ROOT) == 0))
  		return 0;
  
  	arraytop = sizeof(*alist) +
  			context->count * sizeof(alist->al_offset[0]);
  	context->firstu -= ATTR_ENTSIZE(namelen);
  	if (context->firstu < arraytop) {
  		trace_xfs_attr_list_full(context);
  		alist->al_more = 1;
  		context->seen_enough = 1;

  		return 0;

  	}
  
  	aep = (attrlist_ent_t *)&context->alist[context->firstu];
  	aep->a_valuelen = valuelen;
  	memcpy(aep->a_name, name, namelen);
  	aep->a_name[namelen] = 0;
  	alist->al_offset[context->count++] = context->firstu;
  	alist->al_count = context->count;
  	trace_xfs_attr_list_add(context);
  	return 0;
  }
  
  /*
   * Generate a list of extended attribute names and optionally
   * also value lengths.  Positive return value follows the XFS
   * convention of being an error, zero or negative return code
   * is the length of the buffer returned (negated), indicating
   * success.
   */
  int
  xfs_attr_list(
  	xfs_inode_t	*dp,
  	char		*buffer,
  	int		bufsize,
  	int		flags,
  	attrlist_cursor_kern_t *cursor)
  {
  	xfs_attr_list_context_t context;
  	struct attrlist *alist;
  	int error;
  
  	/*
  	 * Validate the cursor.
  	 */
  	if (cursor->pad1 || cursor->pad2)

  		return -EINVAL;

  	if ((cursor->initted == 0) &&
  	    (cursor->hashval || cursor->blkno || cursor->offset))

  		return -EINVAL;

  
  	/*
  	 * Check for a properly aligned buffer.
  	 */
  	if (((long)buffer) & (sizeof(int)-1))

  		return -EFAULT;

  	if (flags & ATTR_KERNOVAL)
  		bufsize = 0;
  
  	/*
  	 * Initialize the output buffer.
  	 */
  	memset(&context, 0, sizeof(context));
  	context.dp = dp;
  	context.cursor = cursor;
  	context.resynch = 1;
  	context.flags = flags;
  	context.alist = buffer;
  	context.bufsize = (bufsize & ~(sizeof(int)-1));  /* align */
  	context.firstu = context.bufsize;
  	context.put_listent = xfs_attr_put_listent;
  
  	alist = (struct attrlist *)context.alist;
  	alist->al_count = 0;
  	alist->al_more = 0;
  	alist->al_offset[0] = context.bufsize;
  
  	error = xfs_attr_list_int(&context);

  	ASSERT(error <= 0);

  	return error;
  }