/* * 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 <linux/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 "udf_i.h" static int udf_pc_to_char(struct super_block *sb, unsigned char *from, int fromlen, unsigned char *to, int tolen) { struct pathComponent *pc; int elen = 0; int comp_len; unsigned char *p = to; /* Reserve one byte for terminating \0 */ tolen--; while (elen < fromlen) { pc = (struct pathComponent *)(from + elen); elen += sizeof(struct pathComponent); 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) { elen += pc->lengthComponentIdent; break; } /* Fall through */ case 2: if (tolen == 0) return -ENAMETOOLONG; p = to; *p++ = '/'; tolen--; break; case 3: if (tolen < 3) return -ENAMETOOLONG; memcpy(p, "../", 3); p += 3; tolen -= 3; break; case 4: if (tolen < 2) return -ENAMETOOLONG; memcpy(p, "./", 2); p += 2; tolen -= 2; /* that would be . - just ignore */ break; case 5: elen += pc->lengthComponentIdent; if (elen > fromlen) return -EIO; comp_len = udf_get_filename(sb, pc->componentIdent, pc->lengthComponentIdent, p, tolen); if (comp_len < 0) return comp_len; p += comp_len; tolen -= comp_len; if (tolen == 0) return -ENAMETOOLONG; *p++ = '/'; tolen--; break; } } if (p > to + 1) p[-1] = '\0'; else p[0] = '\0'; return 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; unsigned char *p = page_address(page); struct udf_inode_info *iinfo; uint32_t pos; /* We don't support symlinks longer than one block */ if (inode->i_size > inode->i_sb->s_blocksize) { err = -ENAMETOOLONG; goto out_unmap; } 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) { err = -EIO; goto out_unlock_inode; } symlink = bh->b_data; } err = udf_pc_to_char(inode->i_sb, symlink, inode->i_size, p, PAGE_SIZE); brelse(bh); if (err) goto out_unlock_inode; up_read(&iinfo->i_data_sem); SetPageUptodate(page); unlock_page(page); return 0; out_unlock_inode: up_read(&iinfo->i_data_sem); SetPageError(page); out_unmap: unlock_page(page); return err; } /* * symlinks can't do much... */ const struct address_space_operations udf_symlink_aops = { .readpage = udf_symlink_filler, };