nfs2xdr.c

linux 内核源代码

/*
 * 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 <[e-mail]>
 * 		FIFO's need special handling in NFSv2
 */

#include <linux/param.h>
#include <linux/time.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/utsname.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)

/*
 * Common NFS XDR functions as inlines
 */
static inline __be32 *
xdr_encode_fhandle(__be32 *p, const struct nfs_fh *fhandle)
{
	memcpy(p, fhandle->data, NFS2_FHSIZE);
	return p + XDR_QUADLEN(NFS2_FHSIZE);
}

static inline __be32 *
xdr_decode_fhandle(__be32 *p, struct nfs_fh *fhandle)
{
	/* NFSv2 handles have a fixed length */
	fhandle->size = NFS2_FHSIZE;
	memcpy(fhandle->data, p, NFS2_FHSIZE);
	return p + XDR_QUADLEN(NFS2_FHSIZE);
}

static inline __be32*
xdr_encode_time(__be32 *p, struct timespec *timep)
{
	*p++ = htonl(timep->tv_sec);
	/* Convert nanoseconds into microseconds */
	*p++ = htonl(timep->tv_nsec ? timep->tv_nsec / 1000 : 0);
	return p;
}

static inline __be32*
xdr_encode_current_server_time(__be32 *p, struct timespec *timep)
{
	/*
	 * Passing the invalid value useconds=1000000 is a
	 * Sun convention for "set to current server time".
	 * It's needed to make permissions checks for the
	 * "touch" program across v2 mounts to Solaris and
	 * Irix boxes work correctly. See description of
	 * sattr in section 6.1 of "NFS Illustrated" by
	 * Brent Callaghan, Addison-Wesley, ISBN 0-201-32750-5
	 */
	*p++ = htonl(timep->tv_sec);
	*p++ = htonl(1000000);
	return p;
}

static inline __be32*
xdr_decode_time(__be32 *p, struct timespec *timep)
{
	timep->tv_sec = ntohl(*p++);
	/* Convert microseconds into nanoseconds */
	timep->tv_nsec = ntohl(*p++) * 1000;
	return p;
}

static __be32 *
xdr_decode_fattr(__be32 *p, struct nfs_fattr *fattr)
{
	u32 rdev;
	fattr->type = (enum nfs_ftype) ntohl(*p++);
	fattr->mode = ntohl(*p++);
	fattr->nlink = ntohl(*p++);
	fattr->uid = ntohl(*p++);
	fattr->gid = ntohl(*p++);
	fattr->size = ntohl(*p++);
	fattr->du.nfs2.blocksize = ntohl(*p++);
	rdev = ntohl(*p++);
	fattr->du.nfs2.blocks = ntohl(*p++);
	fattr->fsid.major = ntohl(*p++);
	fattr->fsid.minor = 0;
	fattr->fileid = ntohl(*p++);
	p = xdr_decode_time(p, &fattr->atime);
	p = xdr_decode_time(p, &fattr->mtime);
	p = xdr_decode_time(p, &fattr->ctime);
	fattr->valid |= NFS_ATTR_FATTR;
	fattr->rdev = new_decode_dev(rdev);
	if (fattr->type == NFCHR && rdev == NFS2_FIFO_DEV) {
		fattr->type = NFFIFO;
		fattr->mode = (fattr->mode & ~S_IFMT) | S_IFIFO;
		fattr->rdev = 0;
	}
	return p;
}

static inline __be32 *
xdr_encode_sattr(__be32 *p, struct iattr *attr)
{
	const __be32 not_set = __constant_htonl(0xFFFFFFFF);

	*p++ = (attr->ia_valid & ATTR_MODE) ? htonl(attr->ia_mode) : not_set;
	*p++ = (attr->ia_valid & ATTR_UID) ? htonl(attr->ia_uid) : not_set;
	*p++ = (attr->ia_valid & ATTR_GID) ? htonl(attr->ia_gid) : not_set;
	*p++ = (attr->ia_valid & ATTR_SIZE) ? htonl(attr->ia_size) : not_set;

	if (attr->ia_valid & ATTR_ATIME_SET) {
		p = xdr_encode_time(p, &attr->ia_atime);
	} else if (attr->ia_valid & ATTR_ATIME) {
		p = xdr_encode_current_server_time(p, &attr->ia_atime);
	} else {
		*p++ = not_set;
		*p++ = not_set;
	}

	if (attr->ia_valid & ATTR_MTIME_SET) {
		p = xdr_encode_time(p, &attr->ia_mtime);
	} else if (attr->ia_valid & ATTR_MTIME) {
		p = xdr_encode_current_server_time(p, &attr->ia_mtime);
	} else {
		*p++ = not_set;	
		*p++ = not_set;
	}
  	return p;
}

/*
 * NFS encode functions
 */
/*
 * Encode file handle argument
 * GETATTR, READLINK, STATFS
 */
static int
nfs_xdr_fhandle(struct rpc_rqst *req, __be32 *p, struct nfs_fh *fh)
{
	p = xdr_encode_fhandle(p, fh);
	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
	return 0;
}

/*
 * Encode SETATTR arguments
 */
static int
nfs_xdr_sattrargs(struct rpc_rqst *req, __be32 *p, struct nfs_sattrargs *args)
{
	p = xdr_encode_fhandle(p, args->fh);
	p = xdr_encode_sattr(p, args->sattr);
	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
	return 0;
}

/*
 * Encode directory ops argument
 * LOOKUP, RMDIR
 */
static int
nfs_xdr_diropargs(struct rpc_rqst *req, __be32 *p, struct nfs_diropargs *args)
{
	p = xdr_encode_fhandle(p, args->fh);
	p = xdr_encode_array(p, args->name, args->len);
	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
	return 0;
}

/*
 * Encode REMOVE argument
 */
static int
nfs_xdr_removeargs(struct rpc_rqst *req, __be32 *p, const struct nfs_removeargs *args)
{
	p = xdr_encode_fhandle(p, args->fh);
	p = xdr_encode_array(p, args->name.name, args->name.len);
	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
	return 0;
}

/*
 * Arguments to a READ call. Since we read data directly into the page
 * cache, we also set up the reply iovec here so that iov[1] points
 * exactly to the page we want to fetch.
 */
static int
nfs_xdr_readargs(struct rpc_rqst *req, __be32 *p, struct nfs_readargs *args)
{
	struct rpc_auth	*auth = req->rq_task->tk_msg.rpc_cred->cr_auth;
	unsigned int replen;
	u32 offset = (u32)args->offset;
	u32 count = args->count;

	p = xdr_encode_fhandle(p, args->fh);
	*p++ = htonl(offset);
	*p++ = htonl(count);
	*p++ = htonl(count);
	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);

	/* Inline the page array */
	replen = (RPC_REPHDRSIZE + auth->au_rslack + NFS_readres_sz) << 2;
	xdr_inline_pages(&req->rq_rcv_buf, replen,
			 args->pages, args->pgbase, count);
	req->rq_rcv_buf.flags |= XDRBUF_READ;
	return 0;
}

/*
 * Decode READ reply
 */
static int
nfs_xdr_readres(struct rpc_rqst *req, __be32 *p, struct nfs_readres *res)
{
	struct kvec *iov = req->rq_rcv_buf.head;
	int	status, count, recvd, hdrlen;

	if ((status = ntohl(*p++)))
		return -nfs_stat_to_errno(status);
	p = xdr_decode_fattr(p, res->fattr);

	count = ntohl(*p++);
	res->eof = 0;
	hdrlen = (u8 *) p - (u8 *) iov->iov_base;
	if (iov->iov_len < hdrlen) {
		dprintk("NFS: READ reply header overflowed:"
				"length %d > %Zu\n", hdrlen, iov->iov_len);
		return -errno_NFSERR_IO;
	} else if (iov->iov_len != hdrlen) {
		dprintk("NFS: READ header is short. iovec will be shifted.\n");
		xdr_shift_buf(&req->rq_rcv_buf, iov->iov_len - hdrlen);
	}

	recvd = req->rq_rcv_buf.len - hdrlen;
	if (count > recvd) {
		dprintk("NFS: server cheating in read reply: "
			"count %d > recvd %d\n", count, recvd);
		count = recvd;
	}

	dprintk("RPC:      readres OK count %d\n", count);
	if (count < res->count)
		res->count = count;

	return count;
}


/*
 * Write arguments. Splice the buffer to be written into the iovec.
 */
static int
nfs_xdr_writeargs(struct rpc_rqst *req, __be32 *p, struct nfs_writeargs *args)
{
	struct xdr_buf *sndbuf = &req->rq_snd_buf;
	u32 offset = (u32)args->offset;
	u32 count = args->count;

	p = xdr_encode_fhandle(p, args->fh);
	*p++ = htonl(offset);
	*p++ = htonl(offset);
	*p++ = htonl(count);
	*p++ = htonl(count);
	sndbuf->len = xdr_adjust_iovec(sndbuf->head, p);

	/* Copy the page array */
	xdr_encode_pages(sndbuf, args->pages, args->pgbase, count);
	sndbuf->flags |= XDRBUF_WRITE;
	return 0;
}

/*
 * Encode create arguments
 * CREATE, MKDIR
 */
static int
nfs_xdr_createargs(struct rpc_rqst *req, __be32 *p, struct nfs_createargs *args)
{
	p = xdr_encode_fhandle(p, args->fh);
	p = xdr_encode_array(p, args->name, args->len);
	p = xdr_encode_sattr(p, args->sattr);
	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
	return 0;
}

/*
 * Encode RENAME arguments
 */
static int
nfs_xdr_renameargs(struct rpc_rqst *req, __be32 *p, struct nfs_renameargs *args)
{
	p = xdr_encode_fhandle(p, args->fromfh);
	p = xdr_encode_array(p, args->fromname, args->fromlen);
	p = xdr_encode_fhandle(p, args->tofh);
	p = xdr_encode_array(p, args->toname, args->tolen);
	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
	return 0;
}

/*
 * Encode LINK arguments
 */
static int
nfs_xdr_linkargs(struct rpc_rqst *req, __be32 *p, struct nfs_linkargs *args)
{
	p = xdr_encode_fhandle(p, args->fromfh);
	p = xdr_encode_fhandle(p, args->tofh);
	p = xdr_encode_array(p, args->toname, args->tolen);
	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
	return 0;
}

/*
 * Encode SYMLINK arguments
 */
static int
nfs_xdr_symlinkargs(struct rpc_rqst *req, __be32 *p, struct nfs_symlinkargs *args)
{
	struct xdr_buf *sndbuf = &req->rq_snd_buf;
	size_t pad;