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