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/pagemap.h> 30 #include <linux/smp_lock.h> 31 #include <linux/buffer_head.h> 32 #include "udf_i.h" 33 34 static void udf_pc_to_char(struct super_block *sb, unsigned char *from, 35 int fromlen, unsigned char *to) 36 { 37 struct pathComponent *pc; 38 int elen = 0; 39 unsigned char *p = to; 40 41 while (elen < fromlen) { 42 pc = (struct pathComponent *)(from + elen); 43 switch (pc->componentType) { 44 case 1: 45 if (pc->lengthComponentIdent == 0) { 46 p = to; 47 *p++ = '/'; 48 } 49 break; 50 case 3: 51 memcpy(p, "../", 3); 52 p += 3; 53 break; 54 case 4: 55 memcpy(p, "./", 2); 56 p += 2; 57 /* that would be . - just ignore */ 58 break; 59 case 5: 60 p += udf_get_filename(sb, pc->componentIdent, p, 61 pc->lengthComponentIdent); 62 *p++ = '/'; 63 break; 64 } 65 elen += sizeof(struct pathComponent) + pc->lengthComponentIdent; 66 } 67 if (p > to + 1) 68 p[-1] = '\0'; 69 else 70 p[0] = '\0'; 71 } 72 73 static int udf_symlink_filler(struct file *file, struct page *page) 74 { 75 struct inode *inode = page->mapping->host; 76 struct buffer_head *bh = NULL; 77 unsigned char *symlink; 78 int err = -EIO; 79 unsigned char *p = kmap(page); 80 struct udf_inode_info *iinfo; 81 82 lock_kernel(); 83 iinfo = UDF_I(inode); 84 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) { 85 symlink = iinfo->i_ext.i_data + iinfo->i_lenEAttr; 86 } else { 87 bh = sb_bread(inode->i_sb, udf_block_map(inode, 0)); 88 89 if (!bh) 90 goto out; 91 92 symlink = bh->b_data; 93 } 94 95 udf_pc_to_char(inode->i_sb, symlink, inode->i_size, p); 96 brelse(bh); 97 98 unlock_kernel(); 99 SetPageUptodate(page); 100 kunmap(page); 101 unlock_page(page); 102 return 0; 103 104 out: 105 unlock_kernel(); 106 SetPageError(page); 107 kunmap(page); 108 unlock_page(page); 109 return err; 110 } 111 112 /* 113 * symlinks can't do much... 114 */ 115 const struct address_space_operations udf_symlink_aops = { 116 .readpage = udf_symlink_filler, 117 }; 118