* Copyright (c) 2000 Manuel Bouyer.

/* $NetBSD: lockd_lock.c,v 1.34 2017/06/08 03:25:03 chs Exp $ */

/*
* 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.
*
* 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 <stdio.h>
#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/socket.h>
#include <sys/param.h>
#include <sys/mount.h>
#include <sys/queue.h>
#include <sys/wait.h>
#include <rpcsvc/sm_inter.h>
#include <rpcsvc/nlm_prot.h>
#include "lockd_lock.h"
#include "lockd.h"

/* A set of utilities for managing file locking */
LIST_HEAD(lcklst_head, file_lock);
struct lcklst_head lcklst_head = LIST_HEAD_INITIALIZER(lcklst_head);

#define FHANDLE_SIZE_MAX 1024 /* arbitrary big enough value */
typedef struct {
size_t fhsize;
char *fhdata;
} nfs_fhandle_t;

static int
fhcmp(const nfs_fhandle_t *fh1, const nfs_fhandle_t *fh2)
{
return memcmp(fh1->fhdata, fh2->fhdata, MIN(fh1->fhsize, fh2->fhsize));
}

static int
fhconv(nfs_fhandle_t *fh, const netobj *rfh)
{
size_t sz;

sz = rfh->n_len;
if (sz > FHANDLE_SIZE_MAX) {
syslog(LOG_DEBUG,
"received fhandle size %zd, max supported size %d",
sz, FHANDLE_SIZE_MAX);
errno = EINVAL;
return -1;
}
fh->fhdata = malloc(sz);
if (fh->fhdata == NULL) {
return -1;
}
fh->fhsize = sz;
(void)memcpy(fh->fhdata, rfh->n_bytes, sz);
return 0;
}

static void
fhfree(nfs_fhandle_t *fh)
{

free(fh->fhdata);
}

/* struct describing a lock */
struct file_lock {
LIST_ENTRY(file_lock) lcklst;
nfs_fhandle_t filehandle; /* NFS filehandle */
struct sockaddr *addr;
struct nlm4_holder client; /* lock holder */
netobj client_cookie; /* cookie sent by the client */
char client_name[128];
int nsm_status; /* status from the remote lock manager */
int status; /* lock status, see below */
int flags; /* lock flags, see lockd_lock.h */
pid_t locker; /* pid of the child process trying to get the lock */
int fd; /* file descriptor for this lock */
};

/* lock status */
#define LKST_LOCKED 1 /* lock is locked */
#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 */

static struct file_lock *lalloc(void);
void lfree(struct file_lock *);
enum nlm_stats do_lock(struct file_lock *, int);
enum nlm_stats do_unlock(struct file_lock *);
void send_granted(struct file_lock *, int);
void siglock(void);
void sigunlock(void);

/* list of hosts we monitor */
LIST_HEAD(hostlst_head, host);
struct hostlst_head hostlst_head = LIST_HEAD_INITIALIZER(hostlst_head);

/* struct describing a lock */
struct host {
LIST_ENTRY(host) hostlst;
char name[SM_MAXSTRLEN+1];
int refcnt;
};

void do_mon(const char *);

#define LL_FH 0x01
#define LL_NAME 0x02
#define LL_SVID 0x04

static struct file_lock *lock_lookup(struct file_lock *, int);

/*
* lock_lookup: lookup a matching lock.
* called with siglock held.
*/
static struct file_lock *
lock_lookup(struct file_lock *newfl, int flags)
{
struct file_lock *fl;

LIST_FOREACH(fl, &lcklst_head, lcklst) {
if ((flags & LL_SVID) != 0 &&
newfl->client.svid != fl->client.svid)
continue;
if ((flags & LL_NAME) != 0 &&
strcmp(newfl->client_name, fl->client_name) != 0)
continue;
if ((flags & LL_FH) != 0 &&
fhcmp(&newfl->filehandle, &fl->filehandle) != 0)
continue;
/* found */
break;
}

return fl;
}

/*
* testlock(): inform the caller if the requested lock would be granted or not
* returns NULL if lock would granted, or pointer to the current nlm4_holder
* otherwise.
*/

struct nlm4_holder *
/*ARGSUSED*/
testlock(struct nlm4_lock *lock, int flags)
{
struct file_lock *fl;
nfs_fhandle_t filehandle;

/* convert lock to a local filehandle */
if (fhconv(&filehandle, &lock->fh)) {
syslog(LOG_NOTICE, "fhconv failed (%m)");
return NULL; /* XXX */
}

siglock();
/* search through the list for lock holder */
LIST_FOREACH(fl, &lcklst_head, lcklst) {
if (fl->status != LKST_LOCKED)
continue;
if (fhcmp(&fl->filehandle, &filehandle) != 0)
continue;
/* got it ! */
syslog(LOG_DEBUG, "test for %s: found lock held by %s",
lock->caller_name, fl->client_name);
sigunlock();
fhfree(&filehandle);
return (&fl->client);
}
/* not found */
sigunlock();
fhfree(&filehandle);
syslog(LOG_DEBUG, "test for %s: no lock found", lock->caller_name);
return NULL;
}

/*
* getlock: try to acquire the lock.
* If file is already locked and we can sleep, put the lock in the list with
* status LKST_WAITING; it'll be processed later.
* Otherwise try to lock. If we're allowed to block, fork a child which
* will do the blocking lock.
*/
enum nlm_stats
getlock(nlm4_lockargs * lckarg, struct svc_req *rqstp, int flags)
{
struct file_lock *fl, *newfl;
enum nlm_stats retval;
struct sockaddr *addr;

if (grace_expired == 0 && lckarg->reclaim == 0)
return (flags & LOCK_V4) ?
(enum nlm_stats)nlm4_denied_grace_period : nlm_denied_grace_period;

/* allocate new file_lock for this request */
newfl = lalloc();
if (newfl == NULL) {
syslog(LOG_NOTICE, "malloc failed (%m)");
/* failed */
return (flags & LOCK_V4) ?
(enum nlm_stats)nlm4_denied_nolock : nlm_denied_nolocks;
}
if (fhconv(&newfl->filehandle, &lckarg->alock.fh)) {
syslog(LOG_NOTICE, "fhconv failed (%m)");
lfree(newfl);
/* failed */
return (flags & LOCK_V4) ?
(enum nlm_stats)nlm4_denied_nolock : nlm_denied_nolocks;
}
addr = (struct sockaddr *)svc_getrpccaller(rqstp->rq_xprt)->buf;
newfl->addr = malloc((size_t)addr->sa_len);
if (newfl->addr == NULL) {
syslog(LOG_NOTICE, "malloc failed (%m)");
lfree(newfl);
/* failed */
return (flags & LOCK_V4) ?
(enum nlm_stats)nlm4_denied_nolock : nlm_denied_nolocks;
}
(void)memcpy(newfl->addr, addr, (size_t)addr->sa_len);
newfl->client.exclusive = lckarg->exclusive;
newfl->client.svid = lckarg->alock.svid;
newfl->client.oh.n_bytes = malloc(lckarg->alock.oh.n_len);
if (newfl->client.oh.n_bytes == NULL) {
syslog(LOG_NOTICE, "malloc failed (%m)");
lfree(newfl);
return (flags & LOCK_V4) ?
(enum nlm_stats)nlm4_denied_nolock : nlm_denied_nolocks;
}
newfl->client.oh.n_len = lckarg->alock.oh.n_len;
(void)memcpy(newfl->client.oh.n_bytes, lckarg->alock.oh.n_bytes,
lckarg->alock.oh.n_len);
newfl->client.l_offset = lckarg->alock.l_offset;
newfl->client.l_len = lckarg->alock.l_len;
newfl->client_cookie.n_len = lckarg->cookie.n_len;
newfl->client_cookie.n_bytes = malloc(lckarg->cookie.n_len);
if (newfl->client_cookie.n_bytes == NULL) {
syslog(LOG_NOTICE, "malloc failed (%m)");
lfree(newfl);
return (flags & LOCK_V4) ?
(enum nlm_stats)nlm4_denied_nolock : nlm_denied_nolocks;
}
(void)memcpy(newfl->client_cookie.n_bytes, lckarg->cookie.n_bytes,
lckarg->cookie.n_len);
(void)strlcpy(newfl->client_name, lckarg->alock.caller_name,
sizeof(newfl->client_name));
newfl->nsm_status = lckarg->state;
newfl->status = 0;
newfl->flags = flags;
siglock();
/* look for a lock rq from this host for this fh */
fl = lock_lookup(newfl, LL_FH|LL_NAME|LL_SVID);
if (fl) {
/* already locked by this host ??? */
sigunlock();
syslog(LOG_NOTICE, "duplicate lock from %s.%"
PRIu32,
newfl->client_name, newfl->client.svid);
lfree(newfl);
switch(fl->status) {
case LKST_LOCKED:
return (flags & LOCK_V4) ?
(enum nlm_stats)nlm4_granted : nlm_granted;
case LKST_WAITING:
case LKST_PROCESSING:
return (flags & LOCK_V4) ?
(enum nlm_stats)nlm4_blocked : nlm_blocked;
case LKST_DYING:
return (flags & LOCK_V4) ?
(enum nlm_stats)nlm4_denied : nlm_denied;
default:
syslog(LOG_NOTICE, "bad status %d",
fl->status);
return (flags & LOCK_V4) ?
(enum nlm_stats)nlm4_failed : nlm_denied;
}
/* NOTREACHED */
}
fl = lock_lookup(newfl, LL_FH);
if (fl) {
/*
* We already have a lock for this file.
* Put this one in waiting state if allowed to block
*/
if (lckarg->block) {
syslog(LOG_DEBUG, "lock from %s.%" PRIu32 ": "
"already locked, waiting",
lckarg->alock.caller_name,
lckarg->alock.svid);
newfl->status = LKST_WAITING;
LIST_INSERT_HEAD(&lcklst_head, newfl, lcklst);
do_mon(lckarg->alock.caller_name);
sigunlock();
return (flags & LOCK_V4) ?
(enum nlm_stats)nlm4_blocked : nlm_blocked;
} else {
sigunlock();
syslog(LOG_DEBUG, "lock from %s.%" PRIu32 ": "
"already locked, failed",
lckarg->alock.caller_name,
lckarg->alock.svid);
lfree(newfl);
return (flags & LOCK_V4) ?
(enum nlm_stats)nlm4_denied : nlm_denied;
}
/* NOTREACHED */
}

/* no entry for this file yet; add to list */
LIST_INSERT_HEAD(&lcklst_head, newfl, lcklst);
/* do the lock */
retval = do_lock(newfl, lckarg->block);
switch (retval) {
case nlm4_granted:
/* case nlm_granted: is the same as nlm4_granted */
case nlm4_blocked:
/* case nlm_blocked: is the same as nlm4_blocked */
do_mon(lckarg->alock.caller_name);
break;
default:
lfree(newfl);
break;
}
sigunlock();
return retval;
}

/* unlock a filehandle */
enum nlm_stats
unlock(nlm4_lock *lck, int flags)
{
struct file_lock *fl;
nfs_fhandle_t filehandle;
int err = (flags & LOCK_V4) ? (enum nlm_stats)nlm4_granted : nlm_granted;

if (fhconv(&filehandle, &lck->fh)) {
syslog(LOG_NOTICE, "fhconv failed (%m)");
return (flags & LOCK_V4) ? (enum nlm_stats)nlm4_denied : nlm_denied;
}
siglock();
LIST_FOREACH(fl, &lcklst_head, lcklst) {
if (strcmp(fl->client_name, lck->caller_name) ||
fhcmp(&filehandle, &fl->filehandle) != 0 ||
fl->client.oh.n_len != lck->oh.n_len ||
memcmp(fl->client.oh.n_bytes, lck->oh.n_bytes,
fl->client.oh.n_len) != 0 ||
fl->client.svid != lck->svid)
continue;
/* Got it, unlock and remove from the queue */
syslog(LOG_DEBUG, "unlock from %s.%" PRIu32 ": found struct, "
"status %d", lck->caller_name, lck->svid, fl->status);
switch (fl->status) {
case LKST_LOCKED:
err = do_unlock(fl);
break;
case LKST_WAITING:
/* remove from the list */
LIST_REMOVE(fl, lcklst);
lfree(fl);
break;
case LKST_PROCESSING:
/*
* being handled by a child; will clean up
* when the child exits
*/
fl->status = LKST_DYING;
break;
case LKST_DYING:
/* nothing to do */
break;
default:
syslog(LOG_NOTICE, "unknown status %d for %s",
fl->status, fl->client_name);
}
sigunlock();
fhfree(&filehandle);
return err;
}
sigunlock();
/* didn't find a matching entry; log anyway */
syslog(LOG_NOTICE, "no matching entry for %s",
lck->caller_name);
fhfree(&filehandle);
return (flags & LOCK_V4) ? (enum nlm_stats)nlm4_granted : nlm_granted;
}

static struct file_lock *
lalloc(void)
{
return calloc(1, sizeof(struct file_lock));
}

void
lfree(struct file_lock *fl)
{
free(fl->addr);
free(fl->client.oh.n_bytes);
free(fl->client_cookie.n_bytes);
fhfree(&fl->filehandle);
free(fl);
}

void
/*ARGSUSED*/
sigchild_handler(int sig)
{
int sstatus;
pid_t pid;
struct file_lock *fl;

for (;;) {
pid = wait4(-1, &sstatus, WNOHANG, NULL);
if (pid == -1) {
if (errno != ECHILD)
syslog(LOG_NOTICE, "wait failed (%m)");
else
syslog(LOG_DEBUG, "wait failed (%m)");
return;
}
if (pid == 0) {
/* no more child to handle yet */
return;
}
/*
* if we're here we have a child that exited
* Find the associated file_lock.
*/
LIST_FOREACH(fl, &lcklst_head, lcklst) {
if (pid == fl->locker)
break;
}
if (fl == NULL) {
syslog(LOG_NOTICE, "unknown child %d", pid);
} else {
/*
* protect from pid reusing.
*/
fl->locker = 0;
if (!WIFEXITED(sstatus) || WEXITSTATUS(sstatus) != 0) {
syslog(LOG_NOTICE, "child %d failed", pid);
/*
* can't do much here; we can't reply
* anything but OK for blocked locks
* Eventually the client will time out
* and retry.
*/
(void)do_unlock(fl);
return;
}

/* check lock status */
syslog(LOG_DEBUG, "processing child %d, status %d",
pid, fl->status);
switch(fl->status) {
case LKST_PROCESSING:
fl->status = LKST_LOCKED;
send_granted(fl, (fl->flags & LOCK_V4) ?
(enum nlm_stats)nlm4_granted : nlm_granted);
break;
case LKST_DYING:
(void)do_unlock(fl);
break;
default:
syslog(LOG_NOTICE, "bad lock status (%d) for"
" child %d", fl->status, pid);
}
}
}
}

/*
*
* try to acquire the lock described by fl. Eventually fork a child to do a
* blocking lock if allowed and required.
*/

enum nlm_stats
do_lock(struct file_lock *fl, int block)
{
int lflags, error;
struct stat st;

fl->fd = fhopen(fl->filehandle.fhdata, fl->filehandle.fhsize, O_RDWR);
if (fl->fd < 0) {
switch (errno) {
case ESTALE:
error = nlm4_stale_fh;
break;
case EROFS:
error = nlm4_rofs;
break;
default:
error = nlm4_failed;
}
if ((fl->flags & LOCK_V4) == 0)
error = nlm_denied;
syslog(LOG_NOTICE, "fhopen failed (from %s) (%m)",
fl->client_name);
LIST_REMOVE(fl, lcklst);
return error;
}
if (fstat(fl->fd, &st) < 0) {
syslog(LOG_NOTICE, "fstat failed (from %s) (%m)",
fl->client_name);
}
syslog(LOG_DEBUG, "lock from %s.%" PRIu32 " for file%s%s: "
"dev %llu ino %llu (uid %d), flags %d",
fl->client_name, fl->client.svid,
fl->client.exclusive ? " (exclusive)":"", block ? " (block)":"",
(unsigned long long)st.st_dev,
(unsigned long long)st.st_ino, st.st_uid, fl->flags);
lflags = LOCK_NB;
if (fl->client.exclusive == 0)
lflags |= LOCK_SH;
else
lflags |= LOCK_EX;
error = flock(fl->fd, lflags);
if (error != 0 && errno == EAGAIN && block) {
switch (fl->locker = fork()) {
case -1: /* fork failed */
syslog(LOG_NOTICE, "fork failed (%m)");
LIST_REMOVE(fl, lcklst);
(void)close(fl->fd);
return (fl->flags & LOCK_V4) ?
(enum nlm_stats)nlm4_denied_nolock : nlm_denied_nolocks;
case 0:
/*
* Attempt a blocking lock. Will have to call
* NLM_GRANTED later.
*/
setproctitle("%s.%" PRIu32,
fl->client_name, fl->client.svid);
lflags &= ~LOCK_NB;
if(flock(fl->fd, lflags) != 0) {
syslog(LOG_NOTICE, "flock failed (%m)");
_exit(1);
}
/* lock granted */
_exit(0);
/*NOTREACHED*/
default:
syslog(LOG_DEBUG, "lock request from %s.%" PRIu32 ": "
"forked %d",
fl->client_name, fl->client.svid, fl->locker);
fl->status = LKST_PROCESSING;
return (fl->flags & LOCK_V4) ?
(enum nlm_stats)nlm4_blocked : nlm_blocked;
}
}
/* non block case */
if (error != 0) {
switch (errno) {
case EAGAIN:
error = nlm4_denied;
break;
case ESTALE:
error = nlm4_stale_fh;
break;
case EROFS:
error = nlm4_rofs;
break;
default:
error = nlm4_failed;
}
if ((fl->flags & LOCK_V4) == 0)
error = nlm_denied;
if (errno != EAGAIN)
syslog(LOG_NOTICE, "flock for %s failed (%m)",
fl->client_name);
else syslog(LOG_DEBUG, "flock for %s failed (%m)",
fl->client_name);
LIST_REMOVE(fl, lcklst);
(void)close(fl->fd);
return error;
}
fl->status = LKST_LOCKED;
return (fl->flags & LOCK_V4) ? (enum nlm_stats)nlm4_granted : nlm_granted;
}

void
/*ARGSUSED*/
send_granted(struct file_lock *fl, int opcode)
{
CLIENT *cli;
static char dummy;
struct timeval timeo;
int success;
static struct nlm_res retval;
static struct nlm4_res retval4;

cli = get_client(fl->addr, (rpcvers_t)
((fl->flags & LOCK_V4) ? NLM_VERS4 : NLM_VERS));
if (cli == NULL) {
syslog(LOG_NOTICE, "failed to get CLIENT for %s.%" PRIu32,
fl->client_name, fl->client.svid);
/*
* We fail to notify remote that the lock has been granted.
* The client will timeout and retry, the lock will be
* granted at this time.
*/
return;
}
timeo.tv_sec = 0;
timeo.tv_usec = (fl->flags & LOCK_ASYNC) ? 0 : 500000; /* 0.5s */

if (fl->flags & LOCK_V4) {
static nlm4_testargs result;
result.cookie = fl->client_cookie;
result.exclusive = fl->client.exclusive;
result.alock.caller_name = fl->client_name;
result.alock.fh.n_len = fl->filehandle.fhsize;
result.alock.fh.n_bytes = fl->filehandle.fhdata;
result.alock.oh = fl->client.oh;
result.alock.svid = fl->client.svid;
result.alock.l_offset = fl->client.l_offset;
result.alock.l_len = fl->client.l_len;
syslog(LOG_DEBUG, "sending v4 reply%s",
(fl->flags & LOCK_ASYNC) ? " (async)":"");
if (fl->flags & LOCK_ASYNC) {
success = clnt_call(cli, NLM4_GRANTED_MSG,
xdr_nlm4_testargs, &result, xdr_void, &dummy, timeo);
} else {
success = clnt_call(cli, NLM4_GRANTED,
xdr_nlm4_testargs, &result, xdr_nlm4_res,
&retval4, timeo);
}
} else {
static nlm_testargs result;

result.cookie = fl->client_cookie;
result.exclusive = fl->client.exclusive;
result.alock.caller_name = fl->client_name;
result.alock.fh.n_len = fl->filehandle.fhsize;
result.alock.fh.n_bytes = fl->filehandle.fhdata;
result.alock.oh = fl->client.oh;
result.alock.svid = fl->client.svid;
result.alock.l_offset =
(unsigned int)fl->client.l_offset;
result.alock.l_len =
(unsigned int)fl->client.l_len;
syslog(LOG_DEBUG, "sending v1 reply%s",
(fl->flags & LOCK_ASYNC) ? " (async)":"");
if (fl->flags & LOCK_ASYNC) {
success = clnt_call(cli, NLM_GRANTED_MSG,
xdr_nlm_testargs, &result, xdr_void, &dummy, timeo);
} else {
success = clnt_call(cli, NLM_GRANTED,
xdr_nlm_testargs, &result, xdr_nlm_res,
&retval, timeo);
}
}
if (debug_level > 2)
syslog(LOG_DEBUG, "clnt_call returns %d(%s) for granted",
success, clnt_sperrno(success));

}

enum nlm_stats
do_unlock(struct file_lock *rfl)
{
struct file_lock *fl;
int error;
int lockst;

/* unlock the file: closing is enough ! */
if (close(rfl->fd) == -1) {
if (errno == ESTALE)
error = nlm4_stale_fh;
else
error = nlm4_failed;
if ((rfl->flags & LOCK_V4) == 0)
error = nlm_denied;
syslog(LOG_NOTICE, "close failed (from %s) (%m)",
rfl->client_name);
} else {
error = (rfl->flags & LOCK_V4) ?
(enum nlm_stats)nlm4_granted : nlm_granted;
}
LIST_REMOVE(rfl, lcklst);

/* process the next LKST_WAITING lock request for this fh */
LIST_FOREACH(fl, &lcklst_head, lcklst) {
if (fl->status != LKST_WAITING ||
fhcmp(&rfl->filehandle, &fl->filehandle) != 0)
continue;

lockst = do_lock(fl, 1); /* If it's LKST_WAITING we can block */
switch (lockst) {
case nlm4_granted:
/* case nlm_granted: same as nlm4_granted */
send_granted(fl, (fl->flags & LOCK_V4) ?
(enum nlm_stats)nlm4_granted : nlm_granted);
break;
case nlm4_blocked:
/* case nlm_blocked: same as nlm4_blocked */
break;
default:
lfree(fl);
break;
}
break;
}
lfree(rfl);
return error;
}

void
siglock(void)
{
sigset_t block;

(void)sigemptyset(&block);
(void)sigaddset(&block, SIGCHLD);

if (sigprocmask(SIG_BLOCK, &block, NULL) < 0) {
syslog(LOG_WARNING, "siglock failed (%m)");
}
}

void
sigunlock(void)
{
sigset_t block;

(void)sigemptyset(&block);
(void)sigaddset(&block, SIGCHLD);

if (sigprocmask(SIG_UNBLOCK, &block, NULL) < 0) {
syslog(LOG_WARNING, "sigunlock failed (%m)");
}
}

/* monitor a host through rpc.statd, and keep a ref count */
void
do_mon(const char *hostname)
{
static char localhost[] = "localhost";
struct host *hp;
struct mon my_mon;
struct sm_stat_res result;
int retval;

LIST_FOREACH(hp, &hostlst_head, hostlst) {
if (strcmp(hostname, hp->name) == 0) {
/* already monitored, just bump refcnt */
hp->refcnt++;
return;
}
}
/* not found, have to create an entry for it */
hp = malloc(sizeof(struct host));
if (hp == NULL) {
syslog(LOG_WARNING, "can't monitor host %s (%m)",
hostname);
return;
}
(void)strlcpy(hp->name, hostname, sizeof(hp->name));
hp->refcnt = 1;
syslog(LOG_DEBUG, "monitoring host %s", hostname);
(void)memset(&my_mon, 0, sizeof(my_mon));
my_mon.mon_id.mon_name = hp->name;
my_mon.mon_id.my_id.my_name = localhost;
my_mon.mon_id.my_id.my_prog = NLM_PROG;
my_mon.mon_id.my_id.my_vers = NLM_SM;
my_mon.mon_id.my_id.my_proc = NLM_SM_NOTIFY;
if ((retval = callrpc(localhost, SM_PROG, SM_VERS, SM_MON,
(xdrproc_t)xdr_mon, (void *)&my_mon,
(xdrproc_t)xdr_sm_stat_res, (void *)&result)) != 0) {
syslog(LOG_WARNING, "rpc to statd failed (%s)",
clnt_sperrno((enum clnt_stat)retval));
free(hp);
return;
}
if (result.res_stat == stat_fail) {
syslog(LOG_WARNING, "statd failed");
free(hp);
return;
}
LIST_INSERT_HEAD(&hostlst_head, hp, hostlst);
}

void
notify(const char *hostname, int state)
{
struct file_lock *fl, *next_fl;
int err;
syslog(LOG_DEBUG, "notify from %s, new state %d", hostname, state);
/* search all lock for this host; if status changed, release the lock */
siglock();
for (fl = LIST_FIRST(&lcklst_head); fl != NULL; fl = next_fl) {
next_fl = LIST_NEXT(fl, lcklst);
if (strcmp(hostname, fl->client_name) == 0 &&
fl->nsm_status != state) {
syslog(LOG_DEBUG, "state %d, nsm_state %d, unlocking",
fl->status, fl->nsm_status);
switch(fl->status) {
case LKST_LOCKED:
err = do_unlock(fl);
if (err != nlm_granted)
syslog(LOG_DEBUG,
"notify: unlock failed for %s (%d)",
hostname, err);
break;
case LKST_WAITING:
LIST_REMOVE(fl, lcklst);
lfree(fl);
break;
case LKST_PROCESSING:
fl->status = LKST_DYING;
break;
case LKST_DYING:
break;
default:
syslog(LOG_NOTICE, "unknown status %d for %s",
fl->status, fl->client_name);
}
}
}
sigunlock();
}