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/udf_fs.h> 27 #include <linux/time.h> 28 #include <linux/mm.h> 29 #include <linux/stat.h> 30 #include <linux/slab.h> 31 #include <linux/pagemap.h> 32 #include <linux/smp_lock.h> 33 #include <linux/buffer_head.h> 34 #include "udf_i.h" 35 36 static void udf_pc_to_char(struct super_block *sb, char *from, int fromlen, 37 char *to) 38 { 39 struct pathComponent *pc; 40 int elen = 0; 41 char *p = to; 42 43 while (elen < fromlen) { 44 pc = (struct pathComponent *)(from + elen); 45 switch (pc->componentType) { 46 case 1: 47 if (pc->lengthComponentIdent == 0) { 48 p = to; 49 *p++ = '/'; 50 } 51 break; 52 case 3: 53 memcpy(p, "../", 3); 54 p += 3; 55 break; 56 case 4: 57 memcpy(p, "./", 2); 58 p += 2; 59 /* that would be . - just ignore */ 60 break; 61 case 5: 62 p += udf_get_filename(sb, pc->componentIdent, p, 63 pc->lengthComponentIdent); 64 *p++ = '/'; 65 break; 66 } 67 elen += sizeof(struct pathComponent) + pc->lengthComponentIdent; 68 } 69 if (p > to + 1) 70 p[-1] = '\0'; 71 else 72 p[0] = '\0'; 73 } 74 75 static int udf_symlink_filler(struct file *file, struct page *page) 76 { 77 struct inode *inode = page->mapping->host; 78 struct buffer_head *bh = NULL; 79 char *symlink; 80 int err = -EIO; 81 char *p = kmap(page); 82 struct udf_inode_info *iinfo; 83 84 lock_kernel(); 85 iinfo = UDF_I(inode); 86 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) { 87 symlink = iinfo->i_ext.i_data + iinfo->i_lenEAttr; 88 } else { 89 bh = sb_bread(inode->i_sb, udf_block_map(inode, 0)); 90 91 if (!bh) 92 goto out; 93 94 symlink = bh->b_data; 95 } 96 97 udf_pc_to_char(inode->i_sb, symlink, inode->i_size, p); 98 brelse(bh); 99 100 unlock_kernel(); 101 SetPageUptodate(page); 102 kunmap(page); 103 unlock_page(page); 104 return 0; 105 106 out: 107 unlock_kernel(); 108 SetPageError(page); 109 kunmap(page); 110 unlock_page(page); 111 return err; 112 } 113 114 /* 115 * symlinks can't do much... 116 */ 117 const struct address_space_operations udf_symlink_aops = { 118 .readpage = udf_symlink_filler, 119 }; 120