linux/fs/ncpfs/symlink.c
Al Viro 32c419d95f move internal-only parts of ncpfs headers to fs/ncpfs
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-01-12 20:03:43 -05:00

181 lines
4.2 KiB
C

/*
* 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 <asm/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;
int mode;
__le32 attr;
unsigned int hdr;
DPRINTK("ncp_symlink(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=dentry->d_inode;
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 ----- */