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/buffer_head.h> 31 #include "udf_i.h" 32 33 static void udf_pc_to_char(struct super_block *sb, unsigned char *from, 34 int fromlen, unsigned char *to) 35 { 36 struct pathComponent *pc; 37 int elen = 0; 38 unsigned char *p = to; 39 40 while (elen < fromlen) { 41 pc = (struct pathComponent *)(from + elen); 42 switch (pc->componentType) { 43 case 1: 44 if (pc->lengthComponentIdent == 0) { 45 p = to; 46 *p++ = '/'; 47 } 48 break; 49 case 3: 50 memcpy(p, "../", 3); 51 p += 3; 52 break; 53 case 4: 54 memcpy(p, "./", 2); 55 p += 2; 56 /* that would be . - just ignore */ 57 break; 58 case 5: 59 p += udf_get_filename(sb, pc->componentIdent, p, 60 pc->lengthComponentIdent); 61 *p++ = '/'; 62 break; 63 } 64 elen += sizeof(struct pathComponent) + pc->lengthComponentIdent; 65 } 66 if (p > to + 1) 67 p[-1] = '\0'; 68 else 69 p[0] = '\0'; 70 } 71 72 static int udf_symlink_filler(struct file *file, struct page *page) 73 { 74 struct inode *inode = page->mapping->host; 75 struct buffer_head *bh = NULL; 76 unsigned char *symlink; 77 int err = -EIO; 78 unsigned char *p = kmap(page); 79 struct udf_inode_info *iinfo; 80 uint32_t pos; 81 82 iinfo = UDF_I(inode); 83 pos = udf_block_map(inode, 0); 84 85 down_read(&iinfo->i_data_sem); 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, pos); 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 up_read(&iinfo->i_data_sem); 101 SetPageUptodate(page); 102 kunmap(page); 103 unlock_page(page); 104 return 0; 105 106 out: 107 up_read(&iinfo->i_data_sem); 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