xref: /freebsd-head/usr.sbin/rpc.lockd/lockd_lock.c

/*	$NetBSD: lockd_lock.c,v 1.5 2000/11/21 03:47:41 enami Exp $	*/

/*-
 * SPDX-License-Identifier: BSD-4-Clause
 *
 * Copyright (c) 2001 Andrew P. Lentvorski, Jr.
 * Copyright (c) 2000 Manuel Bouyer.
 *
 * 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.
 *
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#define LOCKD_DEBUG

#include <stdio.h>
#ifdef LOCKD_DEBUG
#include <stdarg.h>
#endif
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <syslog.h>
#include <errno.h>
#include <string.h>
#include <signal.h>
#include <rpc/rpc.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/param.h>
#include <sys/mount.h>
#include <sys/wait.h>
#include <rpcsvc/sm_inter.h>
#include <rpcsvc/nlm_prot.h>
#include "lockd_lock.h"
#include "lockd.h"

#define MAXOBJECTSIZE 64
#define MAXBUFFERSIZE 1024

/*
 * A set of utilities for managing file locking
 *
 * XXX: All locks are in a linked list, a better structure should be used
 * to improve search/access efficiency.
 */

/* struct describing a lock */
struct file_lock {
	LIST_ENTRY(file_lock) nfslocklist;
	fhandle_t filehandle; /* NFS filehandle */
	struct sockaddr *addr;
	struct nlm4_holder client; /* lock holder */
	/* XXX: client_cookie used *only* in send_granted */
	netobj client_cookie; /* cookie sent by the client */
	int nsm_status; /* status from the remote lock manager */
	int status; /* lock status, see below */
	int flags; /* lock flags, see lockd_lock.h */
	int blocking; /* blocking lock or not */
	char client_name[SM_MAXSTRLEN];	/* client_name is really variable
					   length and must be last! */
};

LIST_HEAD(nfslocklist_head, file_lock);
struct nfslocklist_head nfslocklist_head = LIST_HEAD_INITIALIZER(nfslocklist_head);

LIST_HEAD(blockedlocklist_head, file_lock);
struct blockedlocklist_head blockedlocklist_head = LIST_HEAD_INITIALIZER(blockedlocklist_head);

/* lock status */
#define LKST_LOCKED	1 /* lock is locked */
/* XXX: Is this flag file specific or lock specific? */
#define LKST_WAITING	2 /* file is already locked by another host */
#define LKST_PROCESSING	3 /* child is trying to acquire the lock */
#define LKST_DYING	4 /* must dies when we get news from the child */

/* struct describing a monitored host */
struct host {
	LIST_ENTRY(host) hostlst;
	int refcnt;
	char name[SM_MAXSTRLEN]; /* name is really variable length and
                                    must be last! */
};
/* list of hosts we monitor */
LIST_HEAD(hostlst_head, host);
struct hostlst_head hostlst_head = LIST_HEAD_INITIALIZER(hostlst_head);

/*
 * File monitoring handlers
 * XXX: These might be able to be removed when kevent support
 * is placed into the hardware lock/unlock routines.  (ie.
 * let the kernel do all the file monitoring)
 */

/* Struct describing a monitored file */
struct monfile {
	LIST_ENTRY(monfile) monfilelist;
	fhandle_t filehandle; /* Local access filehandle */
	int fd; /* file descriptor: remains open until unlock! */
	int refcount;
	int exclusive;
};

/* List of files we monitor */
LIST_HEAD(monfilelist_head, monfile);
struct monfilelist_head monfilelist_head = LIST_HEAD_INITIALIZER(monfilelist_head);

static int debugdelay = 0;

enum nfslock_status { NFS_GRANTED = 0, NFS_GRANTED_DUPLICATE,
		      NFS_DENIED, NFS_DENIED_NOLOCK,
		      NFS_RESERR };

enum hwlock_status { HW_GRANTED = 0, HW_GRANTED_DUPLICATE,
		     HW_DENIED, HW_DENIED_NOLOCK,
		     HW_STALEFH, HW_READONLY, HW_RESERR };

enum partialfilelock_status { PFL_GRANTED=0, PFL_GRANTED_DUPLICATE, PFL_DENIED,
			      PFL_NFSDENIED, PFL_NFSBLOCKED, PFL_NFSDENIED_NOLOCK, PFL_NFSRESERR,
			      PFL_HWDENIED,  PFL_HWBLOCKED,  PFL_HWDENIED_NOLOCK, PFL_HWRESERR};

enum LFLAGS {LEDGE_LEFT, LEDGE_LBOUNDARY, LEDGE_INSIDE, LEDGE_RBOUNDARY, LEDGE_RIGHT};
enum RFLAGS {REDGE_LEFT, REDGE_LBOUNDARY, REDGE_INSIDE, REDGE_RBOUNDARY, REDGE_RIGHT};
/* XXX: WARNING! I HAVE OVERLOADED THIS STATUS ENUM!  SPLIT IT APART INTO TWO */
enum split_status {SPL_DISJOINT=0, SPL_LOCK1=1, SPL_LOCK2=2, SPL_CONTAINED=4, SPL_RESERR=8};

enum partialfilelock_status lock_partialfilelock(struct file_lock *fl);

void send_granted(struct file_lock *fl, int opcode);
void siglock(void);
void sigunlock(void);
void monitor_lock_host(const char *hostname);
void unmonitor_lock_host(char *hostname);

void	copy_nlm4_lock_to_nlm4_holder(const struct nlm4_lock *src,
    const bool_t exclusive, struct nlm4_holder *dest);
struct file_lock *	allocate_file_lock(const netobj *lockowner,
					   const netobj *matchcookie,
					   const struct sockaddr *addr,
					   const char *caller_name);
void	deallocate_file_lock(struct file_lock *fl);
void	fill_file_lock(struct file_lock *fl, const fhandle_t *fh,
		       const bool_t exclusive, const int32_t svid,
    const u_int64_t offset, const u_int64_t len,
    const int state, const int status, const int flags, const int blocking);
int	regions_overlap(const u_int64_t start1, const u_int64_t len1,
    const u_int64_t start2, const u_int64_t len2);
enum split_status  region_compare(const u_int64_t starte, const u_int64_t lene,
    const u_int64_t startu, const u_int64_t lenu,
    u_int64_t *start1, u_int64_t *len1, u_int64_t *start2, u_int64_t *len2);
int	same_netobj(const netobj *n0, const netobj *n1);
int	same_filelock_identity(const struct file_lock *fl0,
    const struct file_lock *fl2);

static void debuglog(char const *fmt, ...);
void dump_static_object(const unsigned char* object, const int sizeof_object,
                        unsigned char* hbuff, const int sizeof_hbuff,
                        unsigned char* cbuff, const int sizeof_cbuff);
void dump_netobj(const struct netobj *nobj);
void dump_filelock(const struct file_lock *fl);
struct file_lock *	get_lock_matching_unlock(const struct file_lock *fl);
enum nfslock_status	test_nfslock(const struct file_lock *fl,
    struct file_lock **conflicting_fl);
enum nfslock_status	lock_nfslock(struct file_lock *fl);
enum nfslock_status	delete_nfslock(struct file_lock *fl);
enum nfslock_status	unlock_nfslock(const struct file_lock *fl,
    struct file_lock **released_lock, struct file_lock **left_lock,
    struct file_lock **right_lock);
enum hwlock_status lock_hwlock(struct file_lock *fl);
enum split_status split_nfslock(const struct file_lock *exist_lock,
    const struct file_lock *unlock_lock, struct file_lock **left_lock,
    struct file_lock **right_lock);
int	duplicate_block(struct file_lock *fl);
void	add_blockingfilelock(struct file_lock *fl);
enum hwlock_status	unlock_hwlock(const struct file_lock *fl);
enum hwlock_status	test_hwlock(const struct file_lock *fl,
    struct file_lock **conflicting_fl);
void	remove_blockingfilelock(struct file_lock *fl);
void	clear_blockingfilelock(const char *hostname);
void	retry_blockingfilelocklist(void);
enum partialfilelock_status	unlock_partialfilelock(
    const struct file_lock *fl);
void	clear_partialfilelock(const char *hostname);
enum partialfilelock_status	test_partialfilelock(
    const struct file_lock *fl, struct file_lock **conflicting_fl);
enum nlm_stats	do_test(struct file_lock *fl,
    struct file_lock **conflicting_fl);
enum nlm_stats	do_unlock(struct file_lock *fl);
enum nlm_stats	do_lock(struct file_lock *fl);
void	do_clear(const char *hostname);
size_t	strnlen(const char *, size_t);

void
debuglog(char const *fmt, ...)
{
	va_list ap;

	if (debug_level < 1) {
		return;
	}

	sleep(debugdelay);

	va_start(ap, fmt);
	vsyslog(LOG_DEBUG, fmt, ap);
	va_end(ap);
}

void
dump_static_object(object, size_object, hbuff, size_hbuff, cbuff, size_cbuff)
	const unsigned char *object;
	const int size_object;
	unsigned char *hbuff;
	const int size_hbuff;
	unsigned char *cbuff;
	const int size_cbuff;
{
	int i, objectsize;

	if (debug_level < 2) {
		return;
	}

	objectsize = size_object;

	if (objectsize == 0) {
		debuglog("object is size 0\n");
	} else {
		if (objectsize > MAXOBJECTSIZE) {
			debuglog("Object of size %d being clamped"
			    "to size %d\n", objectsize, MAXOBJECTSIZE);
			objectsize = MAXOBJECTSIZE;
		}

		if (hbuff != NULL) {
			if (size_hbuff < objectsize*2+1) {
				debuglog("Hbuff not large enough."
				    "  Increase size\n");
			} else {
				for(i=0;i<objectsize;i++) {
					sprintf(hbuff+i*2,"%02x",*(object+i));
				}
				*(hbuff+i*2) = '\0';
			}
		}

		if (cbuff != NULL) {
			if (size_cbuff < objectsize+1) {
				debuglog("Cbuff not large enough."
				    "  Increase Size\n");
			}

			for(i=0;i<objectsize;i++) {
				if (*(object+i) >= 32 && *(object+i) <= 127) {
					*(cbuff+i) = *(object+i);
				} else {
					*(cbuff+i) = '.';
				}
			}
			*(cbuff+i) = '\0';
		}
	}
}

void
dump_netobj(const struct netobj *nobj)
{
	char hbuff[MAXBUFFERSIZE*2];
	char cbuff[MAXBUFFERSIZE];

	if (debug_level < 2) {
		return;
	}

	if (nobj == NULL) {
		debuglog("Null netobj pointer\n");
	}
	else if (nobj->n_len == 0) {
		debuglog("Size zero netobj\n");
	} else {
		dump_static_object(nobj->n_bytes, nobj->n_len,
		    hbuff, sizeof(hbuff), cbuff, sizeof(cbuff));
		debuglog("netobj: len: %d  data: %s :::  %s\n",
		    nobj->n_len, hbuff, cbuff);
	}
}

/* #define DUMP_FILELOCK_VERBOSE */
void
dump_filelock(const struct file_lock *fl)
{
#ifdef DUMP_FILELOCK_VERBOSE
	char hbuff[MAXBUFFERSIZE*2];
	char cbuff[MAXBUFFERSIZE];
#endif

	if (debug_level < 2) {
		return;
	}

	if (fl != NULL) {
		debuglog("Dumping file lock structure @ %p\n", fl);

#ifdef DUMP_FILELOCK_VERBOSE
		dump_static_object((unsigned char *)&fl->filehandle,
		    sizeof(fl->filehandle), hbuff, sizeof(hbuff),
		    cbuff, sizeof(cbuff));
		debuglog("Filehandle: %8s  :::  %8s\n", hbuff, cbuff);
#endif

		debuglog("Dumping nlm4_holder:\n"
		    "exc: %x  svid: %x  offset:len %llx:%llx\n",
		    fl->client.exclusive, fl->client.svid,
		    fl->client.l_offset, fl->client.l_len);

#ifdef DUMP_FILELOCK_VERBOSE
		debuglog("Dumping client identity:\n");
		dump_netobj(&fl->client.oh);

		debuglog("Dumping client cookie:\n");
		dump_netobj(&fl->client_cookie);

		debuglog("nsm: %d  status: %d  flags: %d  svid: %x"
		    "  client_name: %s\n", fl->nsm_status, fl->status,
		    fl->flags, fl->client.svid, fl->client_name);
#endif
	} else {
		debuglog("NULL file lock structure\n");
	}
}

void
copy_nlm4_lock_to_nlm4_holder(src, exclusive, dest)
	const struct nlm4_lock *src;
	const bool_t exclusive;
	struct nlm4_holder *dest;
{

	dest->exclusive = exclusive;
	dest->oh.n_len = src->oh.n_len;
	dest->oh.n_bytes = src->oh.n_bytes;
	dest->svid = src->svid;
	dest->l_offset = src->l_offset;
	dest->l_len = src->l_len;
}


size_t
strnlen(const char *s, size_t len)
{
    size_t n;

    for (n = 0;  s[n] != 0 && n < len; n++)
        ;
    return n;
}

/*
 * allocate_file_lock: Create a lock with the given parameters
 */

struct file_lock *
allocate_file_lock(const netobj *lockowner, const netobj *matchcookie,
		   const struct sockaddr *addr, const char *caller_name)
{
	struct file_lock *newfl;
	size_t n;

	/* Beware of rubbish input! */
	n = strnlen(caller_name, SM_MAXSTRLEN);
	if (n == SM_MAXSTRLEN) {
		return NULL;
	}

	newfl = malloc(sizeof(*newfl) - sizeof(newfl->client_name) + n + 1);
	if (newfl == NULL) {
		return NULL;
	}
	bzero(newfl, sizeof(*newfl) - sizeof(newfl->client_name));
	memcpy(newfl->client_name, caller_name, n);
	newfl->client_name[n] = 0;

	newfl->client.oh.n_bytes = malloc(lockowner->n_len);
	if (newfl->client.oh.n_bytes == NULL) {
		free(newfl);
		return NULL;
	}
	newfl->client.oh.n_len = lockowner->n_len;
	bcopy(lockowner->n_bytes, newfl->client.oh.n_bytes, lockowner->n_len);

	newfl->client_cookie.n_bytes = malloc(matchcookie->n_len);
	if (newfl->client_cookie.n_bytes == NULL) {
		free(newfl->client.oh.n_bytes);
		free(newfl);
		return NULL;
	}
	newfl->client_cookie.n_len = matchcookie->n_len;
	bcopy(matchcookie->n_bytes, newfl->client_cookie.n_bytes, matchcookie->n_len);

	newfl->addr = malloc(addr->sa_len);
	if (newfl->addr == NULL) {
		free(newfl->client_cookie.n_bytes);
		free(newfl->client.oh.n_bytes);
		free(newfl);
		return NULL;
	}
	memcpy(newfl->addr, addr, addr->sa_len);

	return newfl;
}

/*
 * file_file_lock: Force creation of a valid file lock
 */
void
fill_file_lock(struct file_lock *fl, const fhandle_t *fh,
    const bool_t exclusive, const int32_t svid,
    const u_int64_t offset, const u_int64_t len,
    const int state, const int status, const int flags, const int blocking)
{
	bcopy(fh, &fl->filehandle, sizeof(fhandle_t));

	fl->client.exclusive = exclusive;
	fl->client.svid = svid;
	fl->client.l_offset = offset;
	fl->client.l_len = len;

	fl->nsm_status = state;
	fl->status = status;
	fl->flags = flags;
	fl->blocking = blocking;
}

/*
 * deallocate_file_lock: Free all storage associated with a file lock
 */
void
deallocate_file_lock(struct file_lock *fl)
{
	free(fl->addr);
	free(fl->client.oh.n_bytes);
	free(fl->client_cookie.n_bytes);
	free(fl);
}

/*
 * regions_overlap(): This function examines the two provided regions for
 * overlap.
 */
int
regions_overlap(start1, len1, start2, len2)
	const u_int64_t start1, len1, start2, len2;
{
	u_int64_t d1,d2,d3,d4;
	enum split_status result;

	debuglog("Entering region overlap with vals: %llu:%llu--%llu:%llu\n",
		 start1, len1, start2, len2);

	result = region_compare(start1, len1, start2, len2,
	    &d1, &d2, &d3, &d4);

	debuglog("Exiting region overlap with val: %d\n",result);

	if (result == SPL_DISJOINT) {
		return 0;
	} else {
		return 1;
	}
}

/*
 * region_compare(): Examine lock regions and split appropriately
 *
 * XXX: Fix 64 bit overflow problems
 * XXX: Check to make sure I got *ALL* the cases.
 * XXX: This DESPERATELY needs a regression test.
 */
enum split_status
region_compare(starte, lene, startu, lenu,
    start1, len1, start2, len2)
	const u_int64_t starte, lene, startu, lenu;
	u_int64_t *start1, *len1, *start2, *len2;
{
	/*
	 * Please pay attention to the sequential exclusions
	 * of the if statements!!!
	 */
	enum LFLAGS lflags;
	enum RFLAGS rflags;
	enum split_status retval;

	retval = SPL_DISJOINT;

	if (lene == 0 && lenu == 0) {
		/* Examine left edge of locker */
		lflags = LEDGE_INSIDE;
		if (startu < starte) {
			lflags = LEDGE_LEFT;
		} else if (startu == starte) {
			lflags = LEDGE_LBOUNDARY;
		}

		rflags = REDGE_RBOUNDARY; /* Both are infiinite */

		if (lflags == LEDGE_INSIDE) {
			*start1 = starte;
			*len1 = startu - starte;
		}

		if (lflags == LEDGE_LEFT || lflags == LEDGE_LBOUNDARY) {
			retval = SPL_CONTAINED;
		} else {
			retval = SPL_LOCK1;
		}
	} else if (lene == 0 && lenu != 0) {
		/* Established lock is infinite */
		/* Examine left edge of unlocker */
		lflags = LEDGE_INSIDE;
		if (startu < starte) {
			lflags = LEDGE_LEFT;
		} else if (startu == starte) {
			lflags = LEDGE_LBOUNDARY;
		}

		/* Examine right edge of unlocker */
		if (startu + lenu < starte) {
			/* Right edge of unlocker left of established lock */
			rflags = REDGE_LEFT;
			return SPL_DISJOINT;
		} else if (startu + lenu == starte) {
			/* Right edge of unlocker on start of established lock */
			rflags = REDGE_LBOUNDARY;
			return SPL_DISJOINT;
		} else { /* Infinifty is right of finity */
			/* Right edge of unlocker inside established lock */
			rflags = REDGE_INSIDE;
		}

		if (lflags == LEDGE_INSIDE) {
			*start1 = starte;
			*len1 = startu - starte;
			retval |= SPL_LOCK1;
		}

		if (rflags == REDGE_INSIDE) {
			/* Create right lock */
			*start2 = startu+lenu;
			*len2 = 0;
			retval |= SPL_LOCK2;
		}
	} else if (lene != 0 && lenu == 0) {
		/* Unlocker is infinite */
		/* Examine left edge of unlocker */
		lflags = LEDGE_RIGHT;
		if (startu < starte) {
			lflags = LEDGE_LEFT;
			retval = SPL_CONTAINED;
			return retval;
		} else if (startu == starte) {
			lflags = LEDGE_LBOUNDARY;
			retval = SPL_CONTAINED;
			return retval;
		} else if ((startu > starte) && (startu < starte + lene - 1)) {
			lflags = LEDGE_INSIDE;
		} else if (startu == starte + lene - 1) {
			lflags = LEDGE_RBOUNDARY;
		} else { /* startu > starte + lene -1 */
			lflags = LEDGE_RIGHT;
			return SPL_DISJOINT;
		}

		rflags = REDGE_RIGHT; /* Infinity is right of finity */

		if (lflags == LEDGE_INSIDE || lflags == LEDGE_RBOUNDARY) {
			*start1 = starte;
			*len1 = startu - starte;
			retval |= SPL_LOCK1;
			return retval;
		}
	} else {
		/* Both locks are finite */

		/* Examine left edge of unlocker */
		lflags = LEDGE_RIGHT;
		if (startu < starte) {
			lflags = LEDGE_LEFT;
		} else if (startu == starte) {
			lflags = LEDGE_LBOUNDARY;
		} else if ((startu > starte) && (startu < starte + lene - 1)) {
			lflags = LEDGE_INSIDE;
		} else if (startu == starte + lene - 1) {
			lflags = LEDGE_RBOUNDARY;
		} else { /* startu > starte + lene -1 */
			lflags = LEDGE_RIGHT;
			return SPL_DISJOINT;
		}

		/* Examine right edge of unlocker */
		if (startu + lenu < starte) {
			/* Right edge of unlocker left of established lock */
			rflags = REDGE_LEFT;
			return SPL_DISJOINT;
		} else if (startu + lenu == starte) {
			/* Right edge of unlocker on start of established lock */
			rflags = REDGE_LBOUNDARY;
			return SPL_DISJOINT;
		} else if (startu + lenu < starte + lene) {
			/* Right edge of unlocker inside established lock */
			rflags = REDGE_INSIDE;
		} else if (startu + lenu == starte + lene) {
			/* Right edge of unlocker on right edge of established lock */
			rflags = REDGE_RBOUNDARY;
		} else { /* startu + lenu > starte + lene */
			/* Right edge of unlocker is right of established lock */
			rflags = REDGE_RIGHT;
		}

		if (lflags == LEDGE_INSIDE || lflags == LEDGE_RBOUNDARY) {
			/* Create left lock */
			*start1 = starte;
			*len1 = (startu - starte);
			retval |= SPL_LOCK1;
		}

		if (rflags == REDGE_INSIDE) {
			/* Create right lock */
			*start2 = startu+lenu;
			*len2 = starte+lene-(startu+lenu);
			retval |= SPL_LOCK2;
		}

		if ((lflags == LEDGE_LEFT || lflags == LEDGE_LBOUNDARY) &&
		    (rflags == REDGE_RBOUNDARY || rflags == REDGE_RIGHT)) {
			retval = SPL_CONTAINED;
		}
	}
	return retval;
}

/*
 * same_netobj: Compares the apprpriate bits of a netobj for identity
 */
int
same_netobj(const netobj *n0, const netobj *n1)
{
	int retval;

	retval = 0;

	debuglog("Entering netobj identity check\n");

	if (n0->n_len == n1->n_len) {
		debuglog("Preliminary length check passed\n");
		retval = !bcmp(n0->n_bytes, n1->n_bytes, n0->n_len);
		debuglog("netobj %smatch\n", retval ? "" : "mis");
	}

	return (retval);
}

/*
 * same_filelock_identity: Compares the appropriate bits of a file_lock
 */
int
same_filelock_identity(fl0, fl1)
	const struct file_lock *fl0, *fl1;
{
	int retval;

	retval = 0;

	debuglog("Checking filelock identity\n");

	/*
	 * Check process ids and host information.
	 */
	retval = (fl0->client.svid == fl1->client.svid &&
	    same_netobj(&(fl0->client.oh), &(fl1->client.oh)));

	debuglog("Exiting checking filelock identity: retval: %d\n",retval);

	return (retval);
}

/*
 * Below here are routines associated with manipulating the NFS
 * lock list.
 */

/*
 * get_lock_matching_unlock: Return a lock which matches the given unlock lock
 *                           or NULL otehrwise
 * XXX: It is a shame that this duplicates so much code from test_nfslock.
 */
struct file_lock *
get_lock_matching_unlock(const struct file_lock *fl)
{
	struct file_lock *ifl; /* Iterator */

	debuglog("Entering get_lock_matching_unlock\n");
	debuglog("********Dump of fl*****************\n");
	dump_filelock(fl);

	LIST_FOREACH(ifl, &nfslocklist_head, nfslocklist) {
		debuglog("Pointer to file lock: %p\n",ifl);

		debuglog("****Dump of ifl****\n");
		dump_filelock(ifl);
		debuglog("*******************\n");

		/*
		 * XXX: It is conceivable that someone could use the NLM RPC
		 * system to directly access filehandles.  This may be a
		 * security hazard as the filehandle code may bypass normal
		 * file access controls
		 */
		if (bcmp(&fl->filehandle, &ifl->filehandle, sizeof(fhandle_t)))
			continue;

		debuglog("get_lock_matching_unlock: Filehandles match, "
		    "checking regions\n");

		/* Filehandles match, check for region overlap */
		if (!regions_overlap(fl->client.l_offset, fl->client.l_len,
			ifl->client.l_offset, ifl->client.l_len))
			continue;

		debuglog("get_lock_matching_unlock: Region overlap"
		    " found %llu : %llu -- %llu : %llu\n",
		    fl->client.l_offset,fl->client.l_len,
		    ifl->client.l_offset,ifl->client.l_len);

		/* Regions overlap, check the identity */
		if (!same_filelock_identity(fl,ifl))
			continue;

		debuglog("get_lock_matching_unlock: Duplicate lock id.  Granting\n");
		return (ifl);
	}

	debuglog("Exiting bet_lock_matching_unlock\n");

	return (NULL);
}

/*
 * test_nfslock: check for NFS lock in lock list
 *
 * This routine makes the following assumptions:
 *    1) Nothing will adjust the lock list during a lookup
 *
 * This routine has an intersting quirk which bit me hard.
 * The conflicting_fl is the pointer to the conflicting lock.
 * However, to modify the "*pointer* to the conflicting lock" rather
 * that the "conflicting lock itself" one must pass in a "pointer to
 * the pointer of the conflicting lock".  Gross.
 */

enum nfslock_status
test_nfslock(const struct file_lock *fl, struct file_lock **conflicting_fl)
{
	struct file_lock *ifl; /* Iterator */
	enum nfslock_status retval;

	debuglog("Entering test_nfslock\n");

	retval = NFS_GRANTED;
	(*conflicting_fl) = NULL;

	debuglog("Entering lock search loop\n");

	debuglog("***********************************\n");
	debuglog("Dumping match filelock\n");
	debuglog("***********************************\n");
	dump_filelock(fl);
	debuglog("***********************************\n");

	LIST_FOREACH(ifl, &nfslocklist_head, nfslocklist) {
		if (retval == NFS_DENIED)
			break;

		debuglog("Top of lock loop\n");
		debuglog("Pointer to file lock: %p\n",ifl);

		debuglog("***********************************\n");
		debuglog("Dumping test filelock\n");
		debuglog("***********************************\n");
		dump_filelock(ifl);
		debuglog("***********************************\n");

		/*
		 * XXX: It is conceivable that someone could use the NLM RPC
		 * system to directly access filehandles.  This may be a
		 * security hazard as the filehandle code may bypass normal
		 * file access controls
		 */
		if (bcmp(&fl->filehandle, &ifl->filehandle, sizeof(fhandle_t)))
			continue;

		debuglog("test_nfslock: filehandle match found\n");

		/* Filehandles match, check for region overlap */
		if (!regions_overlap(fl->client.l_offset, fl->client.l_len,
			ifl->client.l_offset, ifl->client.l_len))
			continue;

		debuglog("test_nfslock: Region overlap found"
		    " %llu : %llu -- %llu : %llu\n",
		    fl->client.l_offset,fl->client.l_len,
		    ifl->client.l_offset,ifl->client.l_len);

		/* Regions overlap, check the exclusivity */
		if (!(fl->client.exclusive || ifl->client.exclusive))
			continue;

		debuglog("test_nfslock: Exclusivity failure: %d %d\n",
		    fl->client.exclusive,
		    ifl->client.exclusive);

		if (same_filelock_identity(fl,ifl)) {
			debuglog("test_nfslock: Duplicate id.  Granting\n");
			(*conflicting_fl) = ifl;
			retval = NFS_GRANTED_DUPLICATE;
		} else {
			/* locking attempt fails */
			debuglog("test_nfslock: Lock attempt failed\n");
			debuglog("Desired lock\n");
			dump_filelock(fl);
			debuglog("Conflicting lock\n");
			dump_filelock(ifl);
			(*conflicting_fl) = ifl;
			retval = NFS_DENIED;
		}
	}

	debuglog("Dumping file locks\n");
	debuglog("Exiting test_nfslock\n");

	return (retval);
}

/*
 * lock_nfslock: attempt to create a lock in the NFS lock list
 *
 * This routine tests whether the lock will be granted and then adds
 * the entry to the lock list if so.
 *
 * Argument fl gets modified as its list housekeeping entries get modified
 * upon insertion into the NFS lock list
 *
 * This routine makes several assumptions:
 *    1) It is perfectly happy to grant a duplicate lock from the same pid.
 *       While this seems to be intuitively wrong, it is required for proper
 *       Posix semantics during unlock.  It is absolutely imperative to not
 *       unlock the main lock before the two child locks are established. Thus,
 *       one has to be able to create duplicate locks over an existing lock
 *    2) It currently accepts duplicate locks from the same id,pid
 */

enum nfslock_status
lock_nfslock(struct file_lock *fl)
{
	enum nfslock_status retval;
	struct file_lock *dummy_fl;

	dummy_fl = NULL;

	debuglog("Entering lock_nfslock...\n");

	retval = test_nfslock(fl,&dummy_fl);

	if (retval == NFS_GRANTED || retval == NFS_GRANTED_DUPLICATE) {
		debuglog("Inserting lock...\n");
		dump_filelock(fl);
		LIST_INSERT_HEAD(&nfslocklist_head, fl, nfslocklist);
	}

	debuglog("Exiting lock_nfslock...\n");

	return (retval);
}

/*
 * delete_nfslock: delete an NFS lock list entry
 *
 * This routine is used to delete a lock out of the NFS lock list
 * without regard to status, underlying locks, regions or anything else
 *
 * Note that this routine *does not deallocate memory* of the lock.
 * It just disconnects it from the list.  The lock can then be used
 * by other routines without fear of trashing the list.
 */

enum nfslock_status
delete_nfslock(struct file_lock *fl)
{

	LIST_REMOVE(fl, nfslocklist);

	return (NFS_GRANTED);
}

enum split_status
split_nfslock(exist_lock, unlock_lock, left_lock, right_lock)
	const struct file_lock *exist_lock, *unlock_lock;
	struct file_lock **left_lock, **right_lock;
{
	u_int64_t start1, len1, start2, len2;
	enum split_status spstatus;

	spstatus = region_compare(exist_lock->client.l_offset, exist_lock->client.l_len,
	    unlock_lock->client.l_offset, unlock_lock->client.l_len,
	    &start1, &len1, &start2, &len2);

	if ((spstatus & SPL_LOCK1) != 0) {
		*left_lock = allocate_file_lock(&exist_lock->client.oh, &exist_lock->client_cookie, exist_lock->addr, exist_lock->client_name);
		if (*left_lock == NULL) {
			debuglog("Unable to allocate resource for split 1\n");
			return SPL_RESERR;
		}

		fill_file_lock(*left_lock, &exist_lock->filehandle,
		    exist_lock->client.exclusive, exist_lock->client.svid,
		    start1, len1,
		    exist_lock->nsm_status,
		    exist_lock->status, exist_lock->flags, exist_lock->blocking);
	}

	if ((spstatus & SPL_LOCK2) != 0) {
		*right_lock = allocate_file_lock(&exist_lock->client.oh, &exist_lock->client_cookie, exist_lock->addr, exist_lock->client_name);
		if (*right_lock == NULL) {
			debuglog("Unable to allocate resource for split 1\n");
			if (*left_lock != NULL) {
				deallocate_file_lock(*left_lock);
			}
			return SPL_RESERR;
		}

		fill_file_lock(*right_lock, &exist_lock->filehandle,
		    exist_lock->client.exclusive, exist_lock->client.svid,
		    start2, len2,
		    exist_lock->nsm_status,
		    exist_lock->status, exist_lock->flags, exist_lock->blocking);
	}

	return spstatus;
}

enum nfslock_status
unlock_nfslock(fl, released_lock, left_lock, right_lock)
	const struct file_lock *fl;
	struct file_lock **released_lock;
	struct file_lock **left_lock;
	struct file_lock **right_lock;
{
	struct file_lock *mfl; /* Matching file lock */
	enum nfslock_status retval;
	enum split_status spstatus;

	debuglog("Entering unlock_nfslock\n");

	*released_lock = NULL;
	*left_lock = NULL;
	*right_lock = NULL;

	retval = NFS_DENIED_NOLOCK;

	debuglog("Attempting to match lock...\n");
	mfl = get_lock_matching_unlock(fl);

	if (mfl != NULL) {
		debuglog("Unlock matched.  Querying for split\n");

		spstatus = split_nfslock(mfl, fl, left_lock, right_lock);

		debuglog("Split returned %d %p %p %p %p\n",spstatus,mfl,fl,*left_lock,*right_lock);
		debuglog("********Split dumps********");
		dump_filelock(mfl);
		dump_filelock(fl);
		dump_filelock(*left_lock);
		dump_filelock(*right_lock);
		debuglog("********End Split dumps********");

		if (spstatus == SPL_RESERR) {
			if (*left_lock != NULL) {
				deallocate_file_lock(*left_lock);
				*left_lock = NULL;
			}

			if (*right_lock != NULL) {
				deallocate_file_lock(*right_lock);
				*right_lock = NULL;
			}

			return NFS_RESERR;
		}

		/* Insert new locks from split if required */
		if (*left_lock != NULL) {
			debuglog("Split left activated\n");
			LIST_INSERT_HEAD(&nfslocklist_head, *left_lock, nfslocklist);
		}

		if (*right_lock != NULL) {
			debuglog("Split right activated\n");