nfs_ops.c

早期freebsd实现

/*-
 * Copyright (c) 1990 Jan-Simon Pendry
 * Copyright (c) 1990 Imperial College of Science, Technology & Medicine
 * Copyright (c) 1990, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Jan-Simon Pendry at Imperial College, London.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $Id: nfs_ops.c,v 5.2.2.2 1992/05/31 16:35:05 jsp Exp $
 */

#ifndef lint
static char sccsid[] = "@(#)nfs_ops.c	8.1 (Berkeley) 6/6/93";
#endif /* not lint */

#include "am.h"
#include <sys/stat.h>

#ifdef HAS_NFS

#define NFS
#define NFSCLIENT
#ifdef NFS_3
typedef nfs_fh fhandle_t;
#endif /* NFS_3 */
#ifdef NFS_HDR
#include NFS_HDR
#endif /* NFS_HDR */
#include <sys/mount.h>
#include "mount.h"

/*
 * Network file system
 */

/*
 * Convert from nfsstat to UN*X error code
 */
#define unx_error(e)	((int)(e))

/*
 * The NFS layer maintains a cache of file handles.
 * This is *fundamental* to the implementation and
 * also allows quick remounting when a filesystem
 * is accessed soon after timing out.
 *
 * The NFS server layer knows to flush this cache
 * when a server goes down so avoiding stale handles.
 *
 * Each cache entry keeps a hard reference to
 * the corresponding server.  This ensures that
 * the server keepalive information is maintained.
 *
 * The copy of the sockaddr_in here is taken so
 * that the port can be twiddled to talk to mountd
 * instead of portmap or the NFS server as used
 * elsewhere.
 * The port# is flushed if a server goes down.
 * The IP address is never flushed - we assume
 * that the address of a mounted machine never
 * changes.  If it does, then you have other
 * problems...
 */
typedef struct fh_cache fh_cache;
struct fh_cache {
	qelem	fh_q;			/* List header */
	voidp	fh_wchan;		/* Wait channel */
	int	fh_error;		/* Valid data? */
	int	fh_id;			/* Unique id */
	int	fh_cid;			/* Callout id */
	struct fhstatus fh_handle;	/* Handle on filesystem */
	struct sockaddr_in fh_sin;	/* Address of mountd */
	fserver *fh_fs;			/* Server holding filesystem */
	char	*fh_path;		/* Filesystem on host */
};

/*
 * FH_TTL is the time a file handle will remain in the cache since
 * last being used.  If the file handle becomes invalid, then it
 * will be flushed anyway.
 */
#define	FH_TTL		(5 * 60)		/* five minutes */
#define	FH_TTL_ERROR	(30)			/* 30 seconds */

static int fh_id = 0;
#define	FHID_ALLOC()	(++fh_id)
extern qelem fh_head;
qelem fh_head = { &fh_head, &fh_head };

static int call_mountd P((fh_cache*, unsigned long, fwd_fun, voidp));

AUTH *nfs_auth;

static fh_cache *find_nfs_fhandle_cache P((voidp idv, int done));
static fh_cache *find_nfs_fhandle_cache(idv, done)
voidp idv;
int done;
{
	fh_cache *fp, *fp2 = 0;
	int id = (int) idv;

	ITER(fp, fh_cache, &fh_head) {
		if (fp->fh_id == id) {
			fp2 = fp;
			break;
		}
	}

#ifdef DEBUG
	if (fp2) {
		dlog("fh cache gives fp %#x, fs %s", fp2, fp2->fh_path);
	} else {
		dlog("fh cache search failed");
	}
#endif /* DEBUG */

	if (fp2 && !done) {
		fp2->fh_error = ETIMEDOUT;
		return 0;
	}

	return fp2;
}

/*
 * Called when a filehandle appears
 */
static void got_nfs_fh P((voidp pkt, int len, struct sockaddr_in *sa,
				struct sockaddr_in *ia, voidp idv, int done));
static void got_nfs_fh(pkt, len, sa, ia, idv, done)
voidp pkt;
int len;
struct sockaddr_in *sa, *ia;
voidp idv;
int done;
{
	fh_cache *fp = find_nfs_fhandle_cache(idv, done);
	if (fp) {
		fp->fh_error = pickup_rpc_reply(pkt, len, (voidp) &fp->fh_handle, xdr_fhstatus);
		if (!fp->fh_error) {
#ifdef DEBUG
			dlog("got filehandle for %s:%s", fp->fh_fs->fs_host, fp->fh_path);
#endif /* DEBUG */
			/*
			 * Wakeup anything sleeping on this filehandle
			 */
			if (fp->fh_wchan) {
#ifdef DEBUG
				dlog("Calling wakeup on %#x", fp->fh_wchan);
#endif /* DEBUG */
				wakeup(fp->fh_wchan);
			}
		}
	}
}

void flush_nfs_fhandle_cache P((fserver *fs));
void flush_nfs_fhandle_cache(fs)
fserver *fs;
{
	fh_cache *fp;
	ITER(fp, fh_cache, &fh_head) {
		if (fp->fh_fs == fs || fs == 0) {
			fp->fh_sin.sin_port = (u_short) 0;
			fp->fh_error = -1;
		}
	}
}

static void discard_fh P((fh_cache *fp));
static void discard_fh(fp)
fh_cache *fp;
{
	rem_que(&fp->fh_q);
#ifdef DEBUG
	dlog("Discarding filehandle for %s:%s", fp->fh_fs->fs_host, fp->fh_path);
#endif /* DEBUG */
	free_srvr(fp->fh_fs);
	free((voidp) fp->fh_path);
	free((voidp) fp);
}

/*
 * Determine the file handle for a node
 */
static int prime_nfs_fhandle_cache P((char *path, fserver *fs, struct fhstatus *fhbuf, voidp wchan));
static int prime_nfs_fhandle_cache(path, fs, fhbuf, wchan)
char *path;
fserver *fs;
struct fhstatus *fhbuf;
voidp wchan;
{
	fh_cache *fp, *fp_save = 0;
	int error;
	int reuse_id = FALSE;

#ifdef DEBUG
	dlog("Searching cache for %s:%s", fs->fs_host, path);
#endif /* DEBUG */

	/*
	 * First search the cache
	 */
	ITER(fp, fh_cache, &fh_head) {
		if (fs == fp->fh_fs && strcmp(path, fp->fh_path) == 0) {
			switch (fp->fh_error) {
			case 0:
				error = fp->fh_error = unx_error(fp->fh_handle.fhs_status);
				if (error == 0) {
					if (fhbuf)
						bcopy((voidp) &fp->fh_handle, (voidp) fhbuf,
							sizeof(fp->fh_handle));
					if (fp->fh_cid)
						untimeout(fp->fh_cid);
					fp->fh_cid = timeout(FH_TTL, discard_fh, (voidp) fp);
				} else if (error == EACCES) {
					/*
					 * Now decode the file handle return code.
					 */
					plog(XLOG_INFO, "Filehandle denied for \"%s:%s\"",
						fs->fs_host, path);
				} else {
					errno = error;	/* XXX */
					plog(XLOG_INFO, "Filehandle error for \"%s:%s\": %m",
						fs->fs_host, path);
				}

				/*
				 * The error was returned from the remote mount daemon.
				 * Policy: this error will be cached for now...
				 */
				return error;

			case -1:
				/*
				 * Still thinking about it, but we can re-use.
				 */
				fp_save = fp;
				reuse_id = TRUE;
				break;

			default:
				/*
				 * Return the error.
				 * Policy: make sure we recompute if required again
				 * in case this was caused by a network failure.
				 * This can thrash mountd's though...  If you find
				 * your mountd going slowly then:
				 * 1.  Add a fork() loop to main.
				 * 2.  Remove the call to innetgr() and don't use
				 *     netgroups, especially if you don't use YP.
				 */
				error = fp->fh_error;
				fp->fh_error = -1;
				return error;
			}
			break;
		}
	}

	/*
	 * Not in cache
	 */
	if (fp_save) {
		fp = fp_save;
		/*
		 * Re-use existing slot
		 */
		untimeout(fp->fh_cid);
		free_srvr(fp->fh_fs);
		free(fp->fh_path);
	} else {
		fp = ALLOC(fh_cache);
		bzero((voidp) fp, sizeof(*fp));
		ins_que(&fp->fh_q, &fh_head);
	}
	if (!reuse_id)
		fp->fh_id = FHID_ALLOC();
	fp->fh_wchan = wchan;
	fp->fh_error = -1;
	fp->fh_cid = timeout(FH_TTL, discard_fh, (voidp) fp);

	/*
	 * If the address has changed then don't try to re-use the
	 * port information
	 */
	if (fp->fh_sin.sin_addr.s_addr != fs->fs_ip->sin_addr.s_addr) {
		fp->fh_sin = *fs->fs_ip;
		fp->fh_sin.sin_port = 0;
	}
	fp->fh_fs = dup_srvr(fs);
	fp->fh_path = strdup(path);

	error = call_mountd(fp, MOUNTPROC_MNT, got_nfs_fh, wchan);
	if (error) {
		/*
		 * Local error - cache for a short period
		 * just to prevent thrashing.
		 */
		untimeout(fp->fh_cid);
		fp->fh_cid = timeout(error < 0 ? 2 * ALLOWED_MOUNT_TIME : FH_TTL_ERROR,
						discard_fh, (voidp) fp);
		fp->fh_error = error;
	} else {
		error = fp->fh_error;
	}
	return error;
}

int make_nfs_auth P((void))
{
#ifdef HAS_NFS_QUALIFIED_NAMES
	/*
	 * From: Chris Metcalf <[e-mail]>
	 * Use hostd, not just hostname.  Note that uids
	 * and gids and the gidlist are type *int* and not the
	 * system uid_t and gid_t types.
	 */
	static int group_wheel = 0;
	nfs_auth = authunix_create(hostd, 0, 0, 1, &group_wheel);
#else
	nfs_auth = authunix_create_default();
#endif
	if (!nfs_auth)
		return ENOBUFS;
	return 0;
}

static int call_mountd P((fh_cache *fp, u_long proc, fwd_fun f, voidp wchan));
static int call_mountd(fp, proc, f, wchan)
fh_cache *fp;
u_long proc;
fwd_fun f;
voidp wchan;
{
	struct rpc_msg mnt_msg;
	int len;
	char iobuf[8192];
	int error;

	if (!nfs_auth) {
		error = make_nfs_auth();
		if (error)
			return error;
	}

	if (fp->fh_sin.sin_port == 0) {
		u_short port;
		error = nfs_srvr_port(fp->fh_fs, &port, wchan);
		if (error)
			return error;
		fp->fh_sin.sin_port = port;
	}

	rpc_msg_init(&mnt_msg, MOUNTPROG, MOUNTVERS, (unsigned long) 0);
	len = make_rpc_packet(iobuf, sizeof(iobuf), proc,
			&mnt_msg, (voidp) &fp->fh_path, xdr_nfspath,  nfs_auth);

	if (len > 0) {
		error = fwd_packet(MK_RPC_XID(RPC_XID_MOUNTD, fp->fh_id),
			(voidp) iobuf, len, &fp->fh_sin, &fp->fh_sin, (voidp) fp->fh_id, f);
	} else {
		error = -len;
	}
/*
 * It may be the case that we're sending to the wrong MOUNTD port.  This
 * occurs if mountd is restarted on the server after the port has been
 * looked up and stored in the filehandle cache somewhere.  The correct
 * solution, if we're going to cache port numbers is to catch the ICMP
 * port unreachable reply from the server and cause the portmap request
 * to be redone.  The quick solution here is to invalidate the MOUNTD
 * port.
 */
      fp->fh_sin.sin_port = 0;

	return error;