nfs2xdr.c

《嵌入式系统设计与实例开发实验教材二源码》Linux内核移植与编译实验

/*
 * 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/sched.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>

/* Uncomment this to support servers requiring longword lengths */
#define NFS_PAD_WRITES 1

#define NFSDBG_FACILITY		NFSDBG_XDR
/* #define NFS_PARANOIA 1 */

extern int			nfs_stat_to_errno(int stat);

/* 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_enc_void_sz		0
#define NFS_diropargs_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+NFS_path_sz+NFS_sattr_sz
#define NFS_readdirargs_sz	NFS_fhandle_sz+2

#define NFS_dec_void_sz		0
#define NFS_attrstat_sz		1+NFS_fattr_sz
#define NFS_diropres_sz		1+NFS_fhandle_sz+NFS_fattr_sz
#define NFS_readlinkres_sz	1
#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 u32 *
xdr_encode_fhandle(u32 *p, struct nfs_fh *fhandle)
{
	memcpy(p, fhandle->data, NFS2_FHSIZE);
	return p + XDR_QUADLEN(NFS2_FHSIZE);
}

static inline u32 *
xdr_decode_fhandle(u32 *p, struct nfs_fh *fhandle)
{
	/* Zero handle first to allow comparisons */
	memset(fhandle, 0, sizeof(*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 u32 *
xdr_decode_string2(u32 *p, char **string, unsigned int *len,
			unsigned int maxlen)
{
	*len = ntohl(*p++);
	if (*len > maxlen)
		return NULL;
	*string = (char *) p;
	return p + XDR_QUADLEN(*len);
}

static inline u32*
xdr_decode_time(u32 *p, u64 *timep)
{
	u64 tmp = (u64)ntohl(*p++) << 32;
	*timep = tmp + (u64)ntohl(*p++);
	return p;
}

static inline u32 *
xdr_decode_fattr(u32 *p, struct nfs_fattr *fattr)
{
	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++);
	fattr->rdev = ntohl(*p++);
	fattr->du.nfs2.blocks = ntohl(*p++);
	fattr->fsid = ntohl(*p++);
	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;
	if (fattr->type == NFCHR && fattr->rdev == NFS2_FIFO_DEV) {
		fattr->type = NFFIFO;
		fattr->mode = (fattr->mode & ~S_IFMT) | S_IFIFO;
		fattr->rdev = 0;
	}
	return p;
}

#define SATTR(p, attr, flag, field) \
        *p++ = (attr->ia_valid & flag) ? htonl(attr->field) : ~(u32) 0
static inline u32 *
xdr_encode_sattr(u32 *p, struct iattr *attr)
{
	SATTR(p, attr, ATTR_MODE, ia_mode);
	SATTR(p, attr, ATTR_UID, ia_uid);
	SATTR(p, attr, ATTR_GID, ia_gid);
	SATTR(p, attr, ATTR_SIZE, ia_size);

	if (attr->ia_valid & (ATTR_ATIME|ATTR_ATIME_SET)) {
		*p++ = htonl(attr->ia_atime);
		*p++ = 0;
	} else {
		*p++ = ~(u32) 0;
		*p++ = ~(u32) 0;
	}

	if (attr->ia_valid & (ATTR_MTIME|ATTR_MTIME_SET)) {
		*p++ = htonl(attr->ia_mtime);
		*p++ = 0;
	} else {
		*p++ = ~(u32) 0;	
		*p++ = ~(u32) 0;
	}
  	return p;
}
#undef SATTR

/*
 * NFS encode functions
 */
/*
 * Encode void argument
 */
static int
nfs_xdr_enc_void(struct rpc_rqst *req, u32 *p, void *dummy)
{
	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
	return 0;
}

/*
 * Encode file handle argument
 * GETATTR, READLINK, STATFS
 */
static int
nfs_xdr_fhandle(struct rpc_rqst *req, u32 *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, u32 *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, REMOVE, RMDIR
 */
static int
nfs_xdr_diropargs(struct rpc_rqst *req, u32 *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;
}

/*
 * 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, u32 *p, struct nfs_readargs *args)
{
	struct rpc_auth	*auth = req->rq_task->tk_auth;
	int		buflen, replen;
	unsigned int	nr;

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

	/* Get the number of buffers in the receive iovec */
        nr = args->nriov;

        if (nr+2 > MAX_IOVEC) {
                printk(KERN_ERR "NFS: Bad number of iov's in xdr_readargs\n");
                return -EINVAL;
        }

	/* set up reply iovec */
	replen = (RPC_REPHDRSIZE + auth->au_rslack + NFS_readres_sz) << 2;
	buflen = req->rq_rvec[0].iov_len;
	req->rq_rvec[0].iov_len  = replen;
        /* Copy the iovec */
        memcpy(req->rq_rvec + 1, args->iov, nr * sizeof(struct iovec));

	req->rq_rvec[nr+1].iov_base = (u8 *) req->rq_rvec[0].iov_base + replen;
	req->rq_rvec[nr+1].iov_len  = buflen - replen;
	req->rq_rlen = args->count + buflen;
	req->rq_rnr += nr+1;

	return 0;
}

/*
 * Decode READ reply
 */
static int
nfs_xdr_readres(struct rpc_rqst *req, u32 *p, struct nfs_readres *res)
{
	struct iovec *iov = req->rq_rvec;
	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++);
	hdrlen = (u8 *) p - (u8 *) iov->iov_base;
	if (iov->iov_len > hdrlen) {
		dprintk("NFS: READ header is short. iovec will be shifted.\n");
		xdr_shift_iovec(iov, req->rq_rnr, iov->iov_len - hdrlen);
	}

	recvd = req->rq_rlen - hdrlen;
	if (count > recvd) {
		printk(KERN_WARNING "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) {
		xdr_zero_iovec(iov+1, req->rq_rnr-2, res->count - count);
		res->count = count;
		res->eof = 1;  /* Silly NFSv3ism which can't be helped */
	} else
		res->eof = 0;

	return count;
}


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

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

	/* Get the number of buffers in the send iovec */
	nr = args->nriov;

	if (nr+2 > MAX_IOVEC) {
                printk(KERN_ERR "NFS: Bad number of iov's in xdr_writeargs "
                        "(nr %d max %d)\n", nr, MAX_IOVEC);
                return -EINVAL;
        }

	/* Copy the iovec */
        memcpy(req->rq_svec + 1, args->iov, nr * sizeof(struct iovec));

#ifdef NFS_PAD_WRITES
	/*
	 * Some old servers require that the message length
	 * be a multiple of 4, so we pad it here if needed.
	 */
	if (count & 3) {
		struct iovec	*iov = req->rq_svec + nr + 1;
		int		pad = 4 - (count & 3);

		iov->iov_base = (void *) "\0\0\0";
		iov->iov_len  = pad;
		count += pad;
		nr++;
	}
#endif
	req->rq_slen += count;
	req->rq_snr += nr;

	return 0;
}

/*
 * Encode create arguments
 * CREATE, MKDIR
 */
static int
nfs_xdr_createargs(struct rpc_rqst *req, u32 *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, u32 *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, u32 *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;
}