/* * linux/fs/ncpfs/symlink.c * * Code for allowing symbolic links on NCPFS (i.e. NetWare) * Symbolic links are not supported on native NetWare, so we use an * infrequently-used flag (Sh) and store a two-word magic header in * the file to make sure we don't accidentally use a non-link file * as a link. * * When using the NFS namespace, we set the mode to indicate a symlink and * don't bother with the magic numbers. * * from linux/fs/ext2/symlink.c * * Copyright (C) 1998-99, Frank A. Vorstenbosch * * ncpfs symlink handling code * NLS support (c) 1999 Petr Vandrovec * Modified 2000 Ben Harris, University of Cambridge for NFS NS meta-info * */ #include <linux/uaccess.h> #include <linux/errno.h> #include <linux/fs.h> #include <linux/time.h> #include <linux/slab.h> #include <linux/mm.h> #include <linux/stat.h> #include "ncp_fs.h" /* these magic numbers must appear in the symlink file -- this makes it a bit more resilient against the magic attributes being set on random files. */ #define NCP_SYMLINK_MAGIC0 cpu_to_le32(0x6c6d7973) /* "symlnk->" */ #define NCP_SYMLINK_MAGIC1 cpu_to_le32(0x3e2d6b6e) /* ----- read a symbolic link ------------------------------------------ */ static int ncp_symlink_readpage(struct file *file, struct page *page) { struct inode *inode = page->mapping->host; int error, length, len; char *link, *rawlink; char *buf = kmap(page); error = -ENOMEM; rawlink = kmalloc(NCP_MAX_SYMLINK_SIZE, GFP_KERNEL); if (!rawlink) goto fail; if (ncp_make_open(inode,O_RDONLY)) goto failEIO; error=ncp_read_kernel(NCP_SERVER(inode),NCP_FINFO(inode)->file_handle, 0,NCP_MAX_SYMLINK_SIZE,rawlink,&length); ncp_inode_close(inode); /* Close file handle if no other users... */ ncp_make_closed(inode); if (error) goto failEIO; if (NCP_FINFO(inode)->flags & NCPI_KLUDGE_SYMLINK) { if (length<NCP_MIN_SYMLINK_SIZE || ((__le32 *)rawlink)[0]!=NCP_SYMLINK_MAGIC0 || ((__le32 *)rawlink)[1]!=NCP_SYMLINK_MAGIC1) goto failEIO; link = rawlink + 8; length -= 8; } else { link = rawlink; } len = NCP_MAX_SYMLINK_SIZE; error = ncp_vol2io(NCP_SERVER(inode), buf, &len, link, length, 0); kfree(rawlink); if (error) goto fail; SetPageUptodate(page); kunmap(page); unlock_page(page); return 0; failEIO: error = -EIO; kfree(rawlink); fail: SetPageError(page); kunmap(page); unlock_page(page); return error; } /* * symlinks can't do much... */ const struct address_space_operations ncp_symlink_aops = { .readpage = ncp_symlink_readpage, }; /* ----- create a new symbolic link -------------------------------------- */ int ncp_symlink(struct inode *dir, struct dentry *dentry, const char *symname) { struct inode *inode; char *rawlink; int length, err, i, outlen; int kludge; umode_t mode; __le32 attr; unsigned int hdr; ncp_dbg(1, "dir=%p, dentry=%p, symname=%s\n", dir, dentry, symname); if (ncp_is_nfs_extras(NCP_SERVER(dir), NCP_FINFO(dir)->volNumber)) kludge = 0; else #ifdef CONFIG_NCPFS_EXTRAS if (NCP_SERVER(dir)->m.flags & NCP_MOUNT_SYMLINKS) kludge = 1; else #endif /* EPERM is returned by VFS if symlink procedure does not exist */ return -EPERM; rawlink = kmalloc(NCP_MAX_SYMLINK_SIZE, GFP_KERNEL); if (!rawlink) return -ENOMEM; if (kludge) { mode = 0; attr = aSHARED | aHIDDEN; ((__le32 *)rawlink)[0]=NCP_SYMLINK_MAGIC0; ((__le32 *)rawlink)[1]=NCP_SYMLINK_MAGIC1; hdr = 8; } else { mode = S_IFLNK | S_IRWXUGO; attr = 0; hdr = 0; } length = strlen(symname); /* map to/from server charset, do not touch upper/lower case as symlink can point out of ncp filesystem */ outlen = NCP_MAX_SYMLINK_SIZE - hdr; err = ncp_io2vol(NCP_SERVER(dir), rawlink + hdr, &outlen, symname, length, 0); if (err) goto failfree; outlen += hdr; err = -EIO; if (ncp_create_new(dir,dentry,mode,0,attr)) { goto failfree; } inode=d_inode(dentry); if (ncp_make_open(inode, O_WRONLY)) goto failfree; if (ncp_write_kernel(NCP_SERVER(inode), NCP_FINFO(inode)->file_handle, 0, outlen, rawlink, &i) || i!=outlen) { goto fail; } ncp_inode_close(inode); ncp_make_closed(inode); kfree(rawlink); return 0; fail:; ncp_inode_close(inode); ncp_make_closed(inode); failfree:; kfree(rawlink); return err; } /* ----- EOF ----- */