path: root/fs/nfs/nfs2xdr.c

/*
 * linux/fs/nfs/nfs2xdr.c
 *
 * XDR functions to encode/decode NFS RPC arguments and results.
 *
 * Copyright (C) 1992, 1993, 1994  Rick Sladkey
 * Copyright (C) 1996 Olaf Kirch
 * 04 Aug 1998  Ion Badulescu <ionut@cs.columbia.edu>
 * 		FIFO's need special handling in NFSv2
 */

#include <linux/param.h>
#include <linux/time.h>
#include <linux/mm.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/in.h>
#include <linux/pagemap.h>
#include <linux/proc_fs.h>
#include <linux/sunrpc/clnt.h>
#include <linux/nfs.h>
#include <linux/nfs2.h>
#include <linux/nfs_fs.h>
#include "internal.h"

#define NFSDBG_FACILITY		NFSDBG_XDR

/* Mapping from NFS error code to "errno" error code. */
#define errno_NFSERR_IO		EIO

/*
 * Declare the space requirements for NFS arguments and replies as
 * number of 32bit-words
 */
#define NFS_fhandle_sz		(8)
#define NFS_sattr_sz		(8)
#define NFS_filename_sz		(1+(NFS2_MAXNAMLEN>>2))
#define NFS_path_sz		(1+(NFS2_MAXPATHLEN>>2))
#define NFS_fattr_sz		(17)
#define NFS_info_sz		(5)
#define NFS_entry_sz		(NFS_filename_sz+3)

#define NFS_diropargs_sz	(NFS_fhandle_sz+NFS_filename_sz)
#define NFS_removeargs_sz	(NFS_fhandle_sz+NFS_filename_sz)
#define NFS_sattrargs_sz	(NFS_fhandle_sz+NFS_sattr_sz)
#define NFS_readlinkargs_sz	(NFS_fhandle_sz)
#define NFS_readargs_sz		(NFS_fhandle_sz+3)
#define NFS_writeargs_sz	(NFS_fhandle_sz+4)
#define NFS_createargs_sz	(NFS_diropargs_sz+NFS_sattr_sz)
#define NFS_renameargs_sz	(NFS_diropargs_sz+NFS_diropargs_sz)
#define NFS_linkargs_sz		(NFS_fhandle_sz+NFS_diropargs_sz)
#define NFS_symlinkargs_sz	(NFS_diropargs_sz+1+NFS_sattr_sz)
#define NFS_readdirargs_sz	(NFS_fhandle_sz+2)

#define NFS_attrstat_sz		(1+NFS_fattr_sz)
#define NFS_diropres_sz		(1+NFS_fhandle_sz+NFS_fattr_sz)
#define NFS_readlinkres_sz	(2)
#define NFS_readres_sz		(1+NFS_fattr_sz+1)
#define NFS_writeres_sz         (NFS_attrstat_sz)
#define NFS_stat_sz		(1)
#define NFS_readdirres_sz	(1)
#define NFS_statfsres_sz	(1+NFS_info_sz)

static int nfs_stat_to_errno(enum nfs_stat);

/*
 * While encoding arguments, set up the reply buffer in advance to
 * receive reply data directly into the page cache.
 */
static void prepare_reply_buffer(struct rpc_rqst *req, struct page **pages,
				 unsigned int base, unsigned int len,
				 unsigned int bufsize)
{
	struct rpc_auth	*auth = req->rq_cred->cr_auth;
	unsigned int replen;

	replen = RPC_REPHDRSIZE + auth->au_rslack + bufsize;
	xdr_inline_pages(&req->rq_rcv_buf, replen << 2, pages, base, len);
}

/*
 * Handle decode buffer overflows out-of-line.
 */
static void print_overflow_msg(const char *func, const struct xdr_stream *xdr)
{
	dprintk("NFS: %s prematurely hit the end of our receive buffer. "
		"Remaining buffer length is %tu words.\n",
		func, xdr->end - xdr->p);
}


/*
 * Encode/decode NFSv2 basic data types
 *
 * Basic NFSv2 data types are defined in section 2.3 of RFC 1094:
 * "NFS: Network File System Protocol Specification".
 *
 * Not all basic data types have their own encoding and decoding
 * functions.  For run-time efficiency, some data types are encoded
 * or decoded inline.
 */

/*
 *	typedef opaque	nfsdata<>;
 */
static int decode_nfsdata(struct xdr_stream *xdr, struct nfs_readres *result)
{
	u32 recvd, count;
	__be32 *p;

	p = xdr_inline_decode(xdr, 4);
	if (unlikely(p == NULL))
		goto out_overflow;
	count = be32_to_cpup(p);
	recvd = xdr_read_pages(xdr, count);
	if (unlikely(count > recvd))
		goto out_cheating;
out:
	result->eof = 0;	/* NFSv2 does not pass EOF flag on the wire. */
	result->count = count;
	return count;
out_cheating:
	dprintk("NFS: server cheating in read result: "
		"count %u > recvd %u\n", count, recvd);
	count = recvd;
	goto out;
out_overflow:
	print_overflow_msg(__func__, xdr);
	return -EIO;
}

/*
 *	enum stat {
 *		NFS_OK = 0,
 *		NFSERR_PERM = 1,
 *		NFSERR_NOENT = 2,
 *		NFSERR_IO = 5,
 *		NFSERR_NXIO = 6,
 *		NFSERR_ACCES = 13,
 *		NFSERR_EXIST = 17,
 *		NFSERR_NODEV = 19,
 *		NFSERR_NOTDIR = 20,
 *		NFSERR_ISDIR = 21,
 *		NFSERR_FBIG = 27,
 *		NFSERR_NOSPC = 28,
 *		NFSERR_ROFS = 30,
 *		NFSERR_NAMETOOLONG = 63,
 *		NFSERR_NOTEMPTY = 66,
 *		NFSERR_DQUOT = 69,
 *		NFSERR_STALE = 70,
 *		NFSERR_WFLUSH = 99
 *	};
 */
static int decode_stat(struct xdr_stream *xdr, enum nfs_stat *status)
{
	__be32 *p;

	p = xdr_inline_decode(xdr, 4);
	if (unlikely(p == NULL))
		goto out_overflow;
	*status = be32_to_cpup(p);
	return 0;
out_overflow:
	print_overflow_msg(__func__, xdr);
	return -EIO;
}

/*
 * 2.3.2.  ftype
 *
 *	enum ftype {
 *		NFNON = 0,
 *		NFREG = 1,
 *		NFDIR = 2,
 *		NFBLK = 3,</