xdr.c

Linux中关于远程文件锁定的支持的源代码

/*
 * linux/fs/lockd/xdr.c
 *
 * XDR support for lockd and the lock client.
 *
 * Copyright (C) 1995, 1996 Olaf Kirch <[e-mail]>
 */

#include <linux/types.h>
#include <linux/sched.h>
#include <linux/utsname.h>
#include <linux/nfs.h>

#include <linux/sunrpc/xdr.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/svc.h>
#include <linux/sunrpc/stats.h>
#include <linux/lockd/lockd.h>

#define NLMDBG_FACILITY		NLMDBG_XDR


static inline loff_t
s32_to_loff_t(__s32 offset)
{
	return (loff_t)offset;
}

static inline __s32
loff_t_to_s32(loff_t offset)
{
	__s32 res;
	if (offset >= NLM_OFFSET_MAX)
		res = NLM_OFFSET_MAX;
	else if (offset <= -NLM_OFFSET_MAX)
		res = -NLM_OFFSET_MAX;
	else
		res = offset;
	return res;
}

/*
 * XDR functions for basic NLM types
 */
static __be32 *nlm_decode_cookie(__be32 *p, struct nlm_cookie *c)
{
	unsigned int	len;

	len = ntohl(*p++);
	
	if(len==0)
	{
		c->len=4;
		memset(c->data, 0, 4);	/* hockeypux brain damage */
	}
	else if(len<=NLM_MAXCOOKIELEN)
	{
		c->len=len;
		memcpy(c->data, p, len);
		p+=XDR_QUADLEN(len);
	}
	else 
	{
		dprintk("lockd: bad cookie size %d (only cookies under "
			"%d bytes are supported.)\n",
				len, NLM_MAXCOOKIELEN);
		return NULL;
	}
	return p;
}

static inline __be32 *
nlm_encode_cookie(__be32 *p, struct nlm_cookie *c)
{
	*p++ = htonl(c->len);
	memcpy(p, c->data, c->len);
	p+=XDR_QUADLEN(c->len);
	return p;
}

static __be32 *
nlm_decode_fh(__be32 *p, struct nfs_fh *f)
{
	unsigned int	len;

	if ((len = ntohl(*p++)) != NFS2_FHSIZE) {
		dprintk("lockd: bad fhandle size %d (should be %d)\n",
			len, NFS2_FHSIZE);
		return NULL;
	}
	f->size = NFS2_FHSIZE;
	memset(f->data, 0, sizeof(f->data));
	memcpy(f->data, p, NFS2_FHSIZE);
	return p + XDR_QUADLEN(NFS2_FHSIZE);
}

static inline __be32 *
nlm_encode_fh(__be32 *p, struct nfs_fh *f)
{
	*p++ = htonl(NFS2_FHSIZE);
	memcpy(p, f->data, NFS2_FHSIZE);
	return p + XDR_QUADLEN(NFS2_FHSIZE);
}

/*
 * Encode and decode owner handle
 */
static inline __be32 *
nlm_decode_oh(__be32 *p, struct xdr_netobj *oh)
{
	return xdr_decode_netobj(p, oh);
}

static inline __be32 *
nlm_encode_oh(__be32 *p, struct xdr_netobj *oh)
{
	return xdr_encode_netobj(p, oh);
}

static __be32 *
nlm_decode_lock(__be32 *p, struct nlm_lock *lock)
{
	struct file_lock	*fl = &lock->fl;
	s32			start, len, end;

	if (!(p = xdr_decode_string_inplace(p, &lock->caller,
					    &lock->len,
					    NLM_MAXSTRLEN))
	 || !(p = nlm_decode_fh(p, &lock->fh))
	 || !(p = nlm_decode_oh(p, &lock->oh)))
		return NULL;
	lock->svid  = ntohl(*p++);

	locks_init_lock(fl);
	fl->fl_owner = current->files;
	fl->fl_pid   = (pid_t)lock->svid;
	fl->fl_flags = FL_POSIX;
	fl->fl_type  = F_RDLCK;		/* as good as anything else */
	start = ntohl(*p++);
	len = ntohl(*p++);
	end = start + len - 1;

	fl->fl_start = s32_to_loff_t(start);

	if (len == 0 || end < 0)
		fl->fl_end = OFFSET_MAX;
	else
		fl->fl_end = s32_to_loff_t(end);
	return p;
}

/*
 * Encode a lock as part of an NLM call
 */
static __be32 *
nlm_encode_lock(__be32 *p, struct nlm_lock *lock)
{
	struct file_lock	*fl = &lock->fl;
	__s32			start, len;

	if (!(p = xdr_encode_string(p, lock->caller))
	 || !(p = nlm_encode_fh(p, &lock->fh))
	 || !(p = nlm_encode_oh(p, &lock->oh)))
		return NULL;

	if (fl->fl_start > NLM_OFFSET_MAX
	 || (fl->fl_end > NLM_OFFSET_MAX && fl->fl_end != OFFSET_MAX))
		return NULL;

	start = loff_t_to_s32(fl->fl_start);
	if (fl->fl_end == OFFSET_MAX)
		len = 0;
	else
		len = loff_t_to_s32(fl->fl_end - fl->fl_start + 1);

	*p++ = htonl(lock->svid);
	*p++ = htonl(start);
	*p++ = htonl(len);

	return p;
}

/*
 * Encode result of a TEST/TEST_MSG call
 */
static __be32 *
nlm_encode_testres(__be32 *p, struct nlm_res *resp)
{
	s32		start, len;

	if (!(p = nlm_encode_cookie(p, &resp->cookie)))
		return NULL;
	*p++ = resp->status;

	if (resp->status == nlm_lck_denied) {
		struct file_lock	*fl = &resp->lock.fl;

		*p++ = (fl->fl_type == F_RDLCK)? xdr_zero : xdr_one;
		*p++ = htonl(resp->lock.svid);

		/* Encode owner handle. */
		if (!(p = xdr_encode_netobj(p, &resp->lock.oh)))
			return NULL;

		start = loff_t_to_s32(fl->fl_start);
		if (fl->fl_end == OFFSET_MAX)
			len = 0;
		else
			len = loff_t_to_s32(fl->fl_end - fl->fl_start + 1);

		*p++ = htonl(start);
		*p++ = htonl(len);
	}

	return p;
}


/*
 * First, the server side XDR functions
 */
int
nlmsvc_decode_testargs(struct svc_rqst *rqstp, __be32 *p, nlm_args *argp)
{
	u32	exclusive;

	if (!(p = nlm_decode_cookie(p, &argp->cookie)))
		return 0;

	exclusive = ntohl(*p++);
	if (!(p = nlm_decode_lock(p, &argp->lock)))
		return 0;
	if (exclusive)
		argp->lock.fl.fl_type = F_WRLCK;

	return xdr_argsize_check(rqstp, p);
}

int
nlmsvc_encode_testres(struct svc_rqst *rqstp, __be32 *p, struct nlm_res *resp)
{
	if (!(p = nlm_encode_testres(p, resp)))
		return 0;
	return xdr_ressize_check(rqstp, p);
}

int
nlmsvc_decode_lockargs(struct svc_rqst *rqstp, __be32 *p, nlm_args *argp)
{
	u32	exclusive;

	if (!(p = nlm_decode_cookie(p, &argp->cookie)))
		return 0;
	argp->block  = ntohl(*p++);
	exclusive    = ntohl(*p++);
	if (!(p = nlm_decode_lock(p, &argp->lock)))
		return 0;
	if (exclusive)
		argp->lock.fl.fl_type = F_WRLCK;
	argp->reclaim = ntohl(*p++);
	argp->state   = ntohl(*p++);
	argp->monitor = 1;		/* monitor client by default */

	return xdr_argsize_check(rqstp, p);
}

int
nlmsvc_decode_cancargs(struct svc_rqst *rqstp, __be32 *p, nlm_args *argp)
{
	u32	exclusive;

	if (!(p = nlm_decode_cookie(p, &argp->cookie)))
		return 0;
	argp->block = ntohl(*p++);
	exclusive = ntohl(*p++);
	if (!(p = nlm_decode_lock(p, &argp->lock)))
		return 0;
	if (exclusive)
		argp->lock.fl.fl_type = F_WRLCK;
	return xdr_argsize_check(rqstp, p);
}

int
nlmsvc_decode_unlockargs(struct svc_rqst *rqstp, __be32 *p, nlm_args *argp)
{
	if (!(p = nlm_decode_cookie(p, &argp->cookie))
	 || !(p = nlm_decode_lock(p, &argp->lock)))
		return 0;
	argp->lock.fl.fl_type = F_UNLCK;
	return xdr_argsize_check(rqstp, p);
}

int
nlmsvc_decode_shareargs(struct svc_rqst *rqstp, __be32 *p, nlm_args *argp)
{
	struct nlm_lock	*lock = &argp->lock;

	memset(lock, 0, sizeof(*lock));
	locks_init_lock(&lock->fl);
	lock->svid = ~(u32) 0;
	lock->fl.fl_pid = (pid_t)lock->svid;

	if (!(p = nlm_decode_cookie(p, &argp->cookie))
	 || !(p = xdr_decode_string_inplace(p, &lock->caller,
					    &lock->len, NLM_MAXSTRLEN))
	 || !(p = nlm_decode_fh(p, &lock->fh))
	 || !(p = nlm_decode_oh(p, &lock->oh)))
		return 0;
	argp->fsm_mode = ntohl(*p++);
	argp->fsm_access = ntohl(*p++);
	return xdr_argsize_check(rqstp, p);
}

int
nlmsvc_encode_shareres(struct svc_rqst *rqstp, __be32 *p, struct nlm_res *resp)
{
	if (!(p = nlm_encode_cookie(p, &resp->cookie)))
		return 0;
	*p++ = resp->status;
	*p++ = xdr_zero;		/* sequence argument */
	return xdr_ressize_check(rqstp, p);
}

int
nlmsvc_encode_res(struct svc_rqst *rqstp, __be32 *p, struct nlm_res *resp)
{
	if (!(p = nlm_encode_cookie(p, &resp->cookie)))
		return 0;
	*p++ = resp->status;
	return xdr_ressize_check(rqstp, p);
}

int
nlmsvc_decode_notify(struct svc_rqst *rqstp, __be32 *p, struct nlm_args *argp)
{
	struct nlm_lock	*lock = &argp->lock;

	if (!(p = xdr_decode_string_inplace(p, &lock->caller,
					    &lock->len, NLM_MAXSTRLEN)))
		return 0;
	argp->state = ntohl(*p++);
	return xdr_argsize_check(rqstp, p);
}

int
nlmsvc_decode_reboot(struct svc_rqst *rqstp, __be32 *p, struct nlm_reboot *argp)
{
	if (!(p = xdr_decode_string_inplace(p, &argp->mon, &argp->len, SM_MAXSTRLEN)))
		return 0;
	argp->state = ntohl(*p++);
	memcpy(&argp->priv.data, p, sizeof(argp->priv.data));
	p += XDR_QUADLEN(SM_PRIV_SIZE);
	return xdr_argsize_check(rqstp, p);
}

int
nlmsvc_decode_res(struct svc_rqst *rqstp, __be32 *p, struct nlm_res *resp)
{
	if (!(p = nlm_decode_cookie(p, &resp->cookie)))
		return 0;
	resp->status = *p++;
	return xdr_argsize_check(rqstp, p);
}

int
nlmsvc_decode_void(struct svc_rqst *rqstp, __be32 *p, void *dummy)
{
	return xdr_argsize_check(rqstp, p);
}

int
nlmsvc_encode_void(struct svc_rqst *rqstp, __be32 *p, void *dummy)
{
	return xdr_ressize_check(rqstp, p);
}

/*
 * Now, the client side XDR functions
 */
#ifdef NLMCLNT_SUPPORT_SHARES
static int
nlmclt_decode_void(struct rpc_rqst *req, u32 *p, void *ptr)
{
	return 0;
}
#endif

static int
nlmclt_encode_testargs(struct rpc_rqst *req, __be32 *p, nlm_args *argp)
{
	struct nlm_lock	*lock = &argp->lock;

	if (!(p = nlm_encode_cookie(p, &argp->cookie)))
		return -EIO;
	*p++ = (lock->fl.fl_type == F_WRLCK)? xdr_one : xdr_zero;
	if (!(p = nlm_encode_lock(p, lock)))
		return -EIO;
	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
	return 0;
}

static int
nlmclt_decode_testres(struct rpc_rqst *req, __be32 *p, struct nlm_res *resp)
{
	if (!(p = nlm_decode_cookie(p, &resp->cookie)))
		return -EIO;
	resp->status = *p++;
	if (resp->status == nlm_lck_denied) {
		struct file_lock	*fl = &resp->lock.fl;
		u32			excl;
		s32			start, len, end;

		memset(&resp->lock, 0, sizeof(resp->lock));
		locks_init_lock(fl);
		excl = ntohl(*p++);
		resp->lock.svid = ntohl(*p++);
		fl->fl_pid = (pid_t)resp->lock.svid;
		if (!(p = nlm_decode_oh(p, &resp->lock.oh)))
			return -EIO;

		fl->fl_flags = FL_POSIX;
		fl->fl_type  = excl? F_WRLCK : F_RDLCK;
		start = ntohl(*p++);
		len = ntohl(*p++);
		end = start + len - 1;

		fl->fl_start = s32_to_loff_t(start);
		if (len == 0 || end < 0)
			fl->fl_end = OFFSET_MAX;
		else
			fl->fl_end = s32_to_loff_t(end);
	}
	return 0;
}


static int
nlmclt_encode_lockargs(struct rpc_rqst *req, __be32 *p, nlm_args *argp)
{
	struct nlm_lock	*lock = &argp->lock;

	if (!(p = nlm_encode_cookie(p, &argp->cookie)))
		return -EIO;
	*p++ = argp->block? xdr_one : xdr_zero;
	*p++ = (lock->fl.fl_type == F_WRLCK)? xdr_one : xdr_zero;
	if (!(p = nlm_encode_lock(p, lock)))
		return -EIO;
	*p++ = argp->reclaim? xdr_one : xdr_zero;
	*p++ = htonl(argp->state);
	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
	return 0;
}

static int
nlmclt_encode_cancargs(struct rpc_rqst *req, __be32 *p, nlm_args *argp)
{
	struct nlm_lock	*lock = &argp->lock;

	if (!(p = nlm_encode_cookie(p, &argp->cookie)))
		return -EIO;
	*p++ = argp->block? xdr_one : xdr_zero;
	*p++ = (lock->fl.fl_type == F_WRLCK)? xdr_one : xdr_zero;
	if (!(p = nlm_encode_lock(p, lock)))
		return -EIO;
	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
	return 0;
}

static int
nlmclt_encode_unlockargs(struct rpc_rqst *req, __be32 *p, nlm_args *argp)
{
	struct nlm_lock	*lock = &argp->lock;

	if (!(p = nlm_encode_cookie(p, &argp->cookie)))
		return -EIO;
	if (!(p = nlm_encode_lock(p, lock)))
		return -EIO;
	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
	return 0;
}

static int
nlmclt_encode_res(struct rpc_rqst *req, __be32 *p, struct nlm_res *resp)
{
	if (!(p = nlm_encode_cookie(p, &resp->cookie)))
		return -EIO;
	*p++ = resp->status;
	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
	return 0;
}

static int
nlmclt_encode_testres(struct rpc_rqst *req, __be32 *p, struct nlm_res *resp)
{
	if (!(p = nlm_encode_testres(p, resp)))
		return -EIO;
	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
	return 0;
}

static int
nlmclt_decode_res(struct rpc_rqst *req, __be32 *p, struct nlm_res *resp)
{
	if (!(p = nlm_decode_cookie(p, &resp->cookie)))
		return -EIO;
	resp->status = *p++;
	return 0;
}

#if (NLMCLNT_OHSIZE > XDR_MAX_NETOBJ)
#  error "NLM host name cannot be larger than XDR_MAX_NETOBJ!"
#endif

/*
 * Buffer requirements for NLM
 */
#define NLM_void_sz		0
#define NLM_cookie_sz		1+XDR_QUADLEN(NLM_MAXCOOKIELEN)
#define NLM_caller_sz		1+XDR_QUADLEN(NLMCLNT_OHSIZE)
#define NLM_owner_sz		1+XDR_QUADLEN(NLMCLNT_OHSIZE)
#define NLM_fhandle_sz		1+XDR_QUADLEN(NFS2_FHSIZE)
#define NLM_lock_sz		3+NLM_caller_sz+NLM_owner_sz+NLM_fhandle_sz
#define NLM_holder_sz		4+NLM_owner_sz

#define NLM_testargs_sz		NLM_cookie_sz+1+NLM_lock_sz
#define NLM_lockargs_sz		NLM_cookie_sz+4+NLM_lock_sz
#define NLM_cancargs_sz		NLM_cookie_sz+2+NLM_lock_sz
#define NLM_unlockargs_sz	NLM_cookie_sz+NLM_lock_sz

#define NLM_testres_sz		NLM_cookie_sz+1+NLM_holder_sz
#define NLM_res_sz		NLM_cookie_sz+1
#define NLM_norep_sz		0

/*
 * For NLM, a void procedure really returns nothing
 */
#define nlmclt_decode_norep	NULL

#define PROC(proc, argtype, restype)	\
[NLMPROC_##proc] = {							\
	.p_proc      = NLMPROC_##proc,					\
	.p_encode    = (kxdrproc_t) nlmclt_encode_##argtype,		\
	.p_decode    = (kxdrproc_t) nlmclt_decode_##restype,		\
	.p_arglen    = NLM_##argtype##_sz,				\
	.p_replen    = NLM_##restype##_sz,				\
	.p_statidx   = NLMPROC_##proc,					\
	.p_name      = #proc,						\
	}

static struct rpc_procinfo	nlm_procedures[] = {
    PROC(TEST,		testargs,	testres),
    PROC(LOCK,		lockargs,	res),
    PROC(CANCEL,	cancargs,	res),
    PROC(UNLOCK,	unlockargs,	res),
    PROC(GRANTED,	testargs,	res),
    PROC(TEST_MSG,	testargs,	norep),
    PROC(LOCK_MSG,	lockargs,	norep),
    PROC(CANCEL_MSG,	cancargs,	norep),
    PROC(UNLOCK_MSG,	unlockargs,	norep),
    PROC(GRANTED_MSG,	testargs,	norep),
    PROC(TEST_RES,	testres,	norep),
    PROC(LOCK_RES,	res,		norep),
    PROC(CANCEL_RES,	res,		norep),
    PROC(UNLOCK_RES,	res,		norep),
    PROC(GRANTED_RES,	res,		norep),
#ifdef NLMCLNT_SUPPORT_SHARES
    PROC(SHARE,		shareargs,	shareres),
    PROC(UNSHARE,	shareargs,	shareres),
    PROC(NM_LOCK,	lockargs,	res),
    PROC(FREE_ALL,	notify,		void),
#endif
};

static struct rpc_version	nlm_version1 = {
		.number		= 1,
		.nrprocs	= 16,
		.procs		= nlm_procedures,
};

static struct rpc_version	nlm_version3 = {
		.number		= 3,
		.nrprocs	= 24,
		.procs		= nlm_procedures,
};

static struct rpc_version *	nlm_versions[] = {
	[1] = &nlm_version1,
	[3] = &nlm_version3,
#ifdef 	CONFIG_LOCKD_V4
	[4] = &nlm_version4,
#endif
};

static struct rpc_stat		nlm_stats;

struct rpc_program		nlm_program = {
		.name		= "lockd",
		.number		= NLM_PROGRAM,
		.nrvers		= ARRAY_SIZE(nlm_versions),
		.version	= nlm_versions,
		.stats		= &nlm_stats,
};

#ifdef RPC_DEBUG
const char *nlmdbg_cookie2a(const struct nlm_cookie *cookie)
{
	/*
	 * We can get away with a static buffer because we're only
	 * called with BKL held.
	 */
	static char buf[2*NLM_MAXCOOKIELEN+1];
	unsigned int i, len = sizeof(buf);
	char *p = buf;

	len--;	/* allow for trailing \0 */
	if (len < 3)
		return "???";
	for (i = 0 ; i < cookie->len ; i++) {
		if (len < 2) {
			strcpy(p-3, "...");
			break;
		}
		sprintf(p, "%02x", cookie->data[i]);
		p += 2;
		len -= 2;
	}
	*p = '\0';

	return buf;
}
#endif