/*
   * symlink.c
   *
   * PURPOSE
   *	Symlink handling routines for the OSTA-UDF(tm) filesystem.
   *

   * COPYRIGHT
   *	This file is distributed under the terms of the GNU General Public
   *	License (GPL). Copies of the GPL can be obtained from:
   *		ftp://prep.ai.mit.edu/pub/gnu/GPL
   *	Each contributing author retains all rights to their own work.
   *
   *  (C) 1998-2001 Ben Fennema

   *  (C) 1999 Stelias Computing Inc

   *
   * HISTORY
   *
   *  04/16/99 blf  Created.
   *
   */
  
  #include "udfdecl.h"
  #include <asm/uaccess.h>
  #include <linux/errno.h>
  #include <linux/fs.h>

  #include <linux/time.h>
  #include <linux/mm.h>
  #include <linux/stat.h>

  #include <linux/pagemap.h>

  #include <linux/buffer_head.h>
  #include "udf_i.h"

  static void udf_pc_to_char(struct super_block *sb, unsigned char *from,
  			   int fromlen, unsigned char *to)

  {
  	struct pathComponent *pc;
  	int elen = 0;

  	unsigned char *p = to;

  	while (elen < fromlen) {

  		pc = (struct pathComponent *)(from + elen);

  		switch (pc->componentType) {
  		case 1:

  			/*
  			 * Symlink points to some place which should be agreed
   			 * upon between originator and receiver of the media. Ignore.
  			 */
  			if (pc->lengthComponentIdent > 0)
  				break;
  			/* Fall through */
  		case 2:
  			p = to;
  			*p++ = '/';

  			break;
  		case 3:
  			memcpy(p, "../", 3);
  			p += 3;
  			break;
  		case 4:
  			memcpy(p, "./", 2);
  			p += 2;
  			/* that would be . - just ignore */
  			break;
  		case 5:
  			p += udf_get_filename(sb, pc->componentIdent, p,
  					      pc->lengthComponentIdent);
  			*p++ = '/';
  			break;

  		}
  		elen += sizeof(struct pathComponent) + pc->lengthComponentIdent;
  	}

  	if (p > to + 1)

  		p[-1] = '\0';
  	else
  		p[0] = '\0';
  }
  
  static int udf_symlink_filler(struct file *file, struct page *page)
  {
  	struct inode *inode = page->mapping->host;
  	struct buffer_head *bh = NULL;

  	unsigned char *symlink;

  	int err = -EIO;

  	unsigned char *p = kmap(page);

  	struct udf_inode_info *iinfo;

  	uint32_t pos;

  	iinfo = UDF_I(inode);

  	pos = udf_block_map(inode, 0);
  
  	down_read(&iinfo->i_data_sem);

  	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
  		symlink = iinfo->i_ext.i_data + iinfo->i_lenEAttr;

  	} else {

  		bh = sb_bread(inode->i_sb, pos);

  
  		if (!bh)
  			goto out;
  
  		symlink = bh->b_data;
  	}
  
  	udf_pc_to_char(inode->i_sb, symlink, inode->i_size, p);

  	brelse(bh);

  	up_read(&iinfo->i_data_sem);

  	SetPageUptodate(page);
  	kunmap(page);
  	unlock_page(page);
  	return 0;

  
  out:

  	up_read(&iinfo->i_data_sem);

  	SetPageError(page);
  	kunmap(page);
  	unlock_page(page);
  	return err;
  }
  
  /*
   * symlinks can't do much...
   */

  const struct address_space_operations udf_symlink_aops = {

  	.readpage		= udf_symlink_filler,

  };