Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/fs/ncpfs/symlink.c |
| 3 | * |
| 4 | * Code for allowing symbolic links on NCPFS (i.e. NetWare) |
| 5 | * Symbolic links are not supported on native NetWare, so we use an |
| 6 | * infrequently-used flag (Sh) and store a two-word magic header in |
| 7 | * the file to make sure we don't accidentally use a non-link file |
| 8 | * as a link. |
| 9 | * |
| 10 | * When using the NFS namespace, we set the mode to indicate a symlink and |
| 11 | * don't bother with the magic numbers. |
| 12 | * |
| 13 | * from linux/fs/ext2/symlink.c |
| 14 | * |
| 15 | * Copyright (C) 1998-99, Frank A. Vorstenbosch |
| 16 | * |
| 17 | * ncpfs symlink handling code |
| 18 | * NLS support (c) 1999 Petr Vandrovec |
| 19 | * Modified 2000 Ben Harris, University of Cambridge for NFS NS meta-info |
| 20 | * |
| 21 | */ |
| 22 | |
| 23 | #include <linux/config.h> |
| 24 | |
| 25 | #include <asm/uaccess.h> |
| 26 | |
| 27 | #include <linux/errno.h> |
| 28 | #include <linux/fs.h> |
| 29 | #include <linux/ncp_fs.h> |
| 30 | #include <linux/time.h> |
| 31 | #include <linux/mm.h> |
| 32 | #include <linux/stat.h> |
| 33 | #include "ncplib_kernel.h" |
| 34 | |
| 35 | |
| 36 | /* these magic numbers must appear in the symlink file -- this makes it a bit |
| 37 | more resilient against the magic attributes being set on random files. */ |
| 38 | |
| 39 | #define NCP_SYMLINK_MAGIC0 cpu_to_le32(0x6c6d7973) /* "symlnk->" */ |
| 40 | #define NCP_SYMLINK_MAGIC1 cpu_to_le32(0x3e2d6b6e) |
| 41 | |
| 42 | /* ----- read a symbolic link ------------------------------------------ */ |
| 43 | |
| 44 | static int ncp_symlink_readpage(struct file *file, struct page *page) |
| 45 | { |
| 46 | struct inode *inode = page->mapping->host; |
| 47 | int error, length, len; |
| 48 | char *link, *rawlink; |
| 49 | char *buf = kmap(page); |
| 50 | |
| 51 | error = -ENOMEM; |
| 52 | rawlink=(char *)kmalloc(NCP_MAX_SYMLINK_SIZE, GFP_KERNEL); |
| 53 | if (!rawlink) |
| 54 | goto fail; |
| 55 | |
| 56 | if (ncp_make_open(inode,O_RDONLY)) |
| 57 | goto failEIO; |
| 58 | |
| 59 | error=ncp_read_kernel(NCP_SERVER(inode),NCP_FINFO(inode)->file_handle, |
| 60 | 0,NCP_MAX_SYMLINK_SIZE,rawlink,&length); |
| 61 | |
| 62 | ncp_inode_close(inode); |
| 63 | /* Close file handle if no other users... */ |
| 64 | ncp_make_closed(inode); |
| 65 | if (error) |
| 66 | goto failEIO; |
| 67 | |
| 68 | if (NCP_FINFO(inode)->flags & NCPI_KLUDGE_SYMLINK) { |
| 69 | if (length<NCP_MIN_SYMLINK_SIZE || |
| 70 | ((__le32 *)rawlink)[0]!=NCP_SYMLINK_MAGIC0 || |
| 71 | ((__le32 *)rawlink)[1]!=NCP_SYMLINK_MAGIC1) |
| 72 | goto failEIO; |
| 73 | link = rawlink + 8; |
| 74 | length -= 8; |
| 75 | } else { |
| 76 | link = rawlink; |
| 77 | } |
| 78 | |
| 79 | len = NCP_MAX_SYMLINK_SIZE; |
| 80 | error = ncp_vol2io(NCP_SERVER(inode), buf, &len, link, length, 0); |
| 81 | kfree(rawlink); |
| 82 | if (error) |
| 83 | goto fail; |
| 84 | SetPageUptodate(page); |
| 85 | kunmap(page); |
| 86 | unlock_page(page); |
| 87 | return 0; |
| 88 | |
| 89 | failEIO: |
| 90 | error = -EIO; |
| 91 | kfree(rawlink); |
| 92 | fail: |
| 93 | SetPageError(page); |
| 94 | kunmap(page); |
| 95 | unlock_page(page); |
| 96 | return error; |
| 97 | } |
| 98 | |
| 99 | /* |
| 100 | * symlinks can't do much... |
| 101 | */ |
Christoph Hellwig | f5e54d6 | 2006-06-28 04:26:44 -0700 | [diff] [blame] | 102 | const struct address_space_operations ncp_symlink_aops = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 103 | .readpage = ncp_symlink_readpage, |
| 104 | }; |
| 105 | |
| 106 | /* ----- create a new symbolic link -------------------------------------- */ |
| 107 | |
| 108 | int ncp_symlink(struct inode *dir, struct dentry *dentry, const char *symname) { |
| 109 | struct inode *inode; |
| 110 | char *rawlink; |
| 111 | int length, err, i, outlen; |
| 112 | int kludge; |
| 113 | int mode; |
| 114 | __le32 attr; |
| 115 | unsigned int hdr; |
| 116 | |
| 117 | DPRINTK("ncp_symlink(dir=%p,dentry=%p,symname=%s)\n",dir,dentry,symname); |
| 118 | |
| 119 | if (ncp_is_nfs_extras(NCP_SERVER(dir), NCP_FINFO(dir)->volNumber)) |
| 120 | kludge = 0; |
| 121 | else |
| 122 | #ifdef CONFIG_NCPFS_EXTRAS |
| 123 | if (NCP_SERVER(dir)->m.flags & NCP_MOUNT_SYMLINKS) |
| 124 | kludge = 1; |
| 125 | else |
| 126 | #endif |
| 127 | /* EPERM is returned by VFS if symlink procedure does not exist */ |
| 128 | return -EPERM; |
| 129 | |
| 130 | rawlink=(char *)kmalloc(NCP_MAX_SYMLINK_SIZE, GFP_KERNEL); |
| 131 | if (!rawlink) |
| 132 | return -ENOMEM; |
| 133 | |
| 134 | if (kludge) { |
| 135 | mode = 0; |
| 136 | attr = aSHARED | aHIDDEN; |
| 137 | ((__le32 *)rawlink)[0]=NCP_SYMLINK_MAGIC0; |
| 138 | ((__le32 *)rawlink)[1]=NCP_SYMLINK_MAGIC1; |
| 139 | hdr = 8; |
| 140 | } else { |
| 141 | mode = S_IFLNK | S_IRWXUGO; |
| 142 | attr = 0; |
| 143 | hdr = 0; |
| 144 | } |
| 145 | |
| 146 | length = strlen(symname); |
| 147 | /* map to/from server charset, do not touch upper/lower case as |
| 148 | symlink can point out of ncp filesystem */ |
| 149 | outlen = NCP_MAX_SYMLINK_SIZE - hdr; |
| 150 | err = ncp_io2vol(NCP_SERVER(dir), rawlink + hdr, &outlen, symname, length, 0); |
| 151 | if (err) |
| 152 | goto failfree; |
| 153 | |
| 154 | outlen += hdr; |
| 155 | |
| 156 | err = -EIO; |
| 157 | if (ncp_create_new(dir,dentry,mode,0,attr)) { |
| 158 | goto failfree; |
| 159 | } |
| 160 | |
| 161 | inode=dentry->d_inode; |
| 162 | |
| 163 | if (ncp_make_open(inode, O_WRONLY)) |
| 164 | goto failfree; |
| 165 | |
| 166 | if (ncp_write_kernel(NCP_SERVER(inode), NCP_FINFO(inode)->file_handle, |
| 167 | 0, outlen, rawlink, &i) || i!=outlen) { |
| 168 | goto fail; |
| 169 | } |
| 170 | |
| 171 | ncp_inode_close(inode); |
| 172 | ncp_make_closed(inode); |
| 173 | kfree(rawlink); |
| 174 | return 0; |
| 175 | fail:; |
| 176 | ncp_inode_close(inode); |
| 177 | ncp_make_closed(inode); |
| 178 | failfree:; |
| 179 | kfree(rawlink); |
| 180 | return err; |
| 181 | } |
| 182 | |
| 183 | /* ----- EOF ----- */ |