1 /* 2 * symlink.c 3 * 4 * PURPOSE 5 * Symlink handling routines for the OSTA-UDF(tm) filesystem. 6 * 7 * COPYRIGHT 8 * This file is distributed under the terms of the GNU General Public 9 * License (GPL). Copies of the GPL can be obtained from: 10 * ftp://prep.ai.mit.edu/pub/gnu/GPL 11 * Each contributing author retains all rights to their own work. 12 * 13 * (C) 1998-2001 Ben Fennema 14 * (C) 1999 Stelias Computing Inc 15 * 16 * HISTORY 17 * 18 * 04/16/99 blf Created. 19 * 20 */ 21 22 #include "udfdecl.h" 23 #include <asm/uaccess.h> 24 #include <linux/errno.h> 25 #include <linux/fs.h> 26 #include <linux/time.h> 27 #include <linux/mm.h> 28 #include <linux/stat.h> 29 #include <linux/slab.h> 30 #include <linux/pagemap.h> 31 #include <linux/smp_lock.h> 32 #include <linux/buffer_head.h> 33 #include "udf_i.h" 34 35 static void udf_pc_to_char(struct super_block *sb, char *from, int fromlen, 36 char *to) 37 { 38 struct pathComponent *pc; 39 int elen = 0; 40 char *p = to; 41 42 while (elen < fromlen) { 43 pc = (struct pathComponent *)(from + elen); 44 switch (pc->componentType) { 45 case 1: 46 if (pc->lengthComponentIdent == 0) { 47 p = to; 48 *p++ = '/'; 49 } 50 break; 51 case 3: 52 memcpy(p, "../", 3); 53 p += 3; 54 break; 55 case 4: 56 memcpy(p, "./", 2); 57 p += 2; 58 /* that would be . - just ignore */ 59 break; 60 case 5: 61 p += udf_get_filename(sb, pc->componentIdent, p, 62 pc->lengthComponentIdent); 63 *p++ = '/'; 64 break; 65 } 66 elen += sizeof(struct pathComponent) + pc->lengthComponentIdent; 67 } 68 if (p > to + 1) 69 p[-1] = '\0'; 70 else 71 p[0] = '\0'; 72 } 73 74 static int udf_symlink_filler(struct file *file, struct page *page) 75 { 76 struct inode *inode = page->mapping->host; 77 struct buffer_head *bh = NULL; 78 char *symlink; 79 int err = -EIO; 80 char *p = kmap(page); 81 struct udf_inode_info *iinfo; 82 83 lock_kernel(); 84 iinfo = UDF_I(inode); 85 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) { 86 symlink = iinfo->i_ext.i_data + iinfo->i_lenEAttr; 87 } else { 88 bh = sb_bread(inode->i_sb, udf_block_map(inode, 0)); 89 90 if (!bh) 91 goto out; 92 93 symlink = bh->b_data; 94 } 95 96 udf_pc_to_char(inode->i_sb, symlink, inode->i_size, p); 97 brelse(bh); 98 99 unlock_kernel(); 100 SetPageUptodate(page); 101 kunmap(page); 102 unlock_page(page); 103 return 0; 104 105 out: 106 unlock_kernel(); 107 SetPageError(page); 108 kunmap(page); 109 unlock_page(page); 110 return err; 111 } 112 113 /* 114 * symlinks can't do much... 115 */ 116 const struct address_space_operations udf_symlink_aops = { 117 .readpage = udf_symlink_filler, 118 }; 119