示例#1
0
文件: srv.c 项目: 99years/plan9
void
respond(Req *r, char *error)
{
	int i, m, n;
	char errbuf[ERRMAX];
	Srv *srv;

	srv = r->srv;
	assert(srv != nil);

	if(r->responded){
		assert(r->pool);
		goto free;
	}
		
	assert(r->responded == 0);
	r->error = error;

	switch(r->ifcall.type){
	default:
		assert(0);
	/*
	 * Flush is special.  If the handler says so, we return
	 * without further processing.  Respond will be called
	 * again once it is safe.
	 */
	case Tflush:
		if(rflush(r, error)<0)
			return;
		break;
	case Tversion:	rversion(r, error);	break;
	case Tauth:	rauth(r, error);	break;
	case Tattach:	rattach(r, error);	break;
	case Twalk:	rwalk(r, error);	break;
	case Topen:	ropen(r, error);	break;
	case Tcreate:	rcreate(r, error);	break;
	case Tread:	rread(r, error);	break;
	case Twrite:	rwrite(r, error);	break;
	case Tclunk:	rclunk(r, error);	break;
	case Tremove:	rremove(r, error, errbuf);	break;
	case Tstat:	rstat(r, error);	break;
	case Twstat:	rwstat(r, error);	break;
	}

	r->ofcall.tag = r->ifcall.tag;
	r->ofcall.type = r->ifcall.type+1;
	if(r->error)
		setfcallerror(&r->ofcall, r->error);

if(chatty9p)
	fprint(2, "-%d-> %F\n", srv->outfd, &r->ofcall);

	qlock(&srv->wlock);
	n = convS2M(&r->ofcall, srv->wbuf, srv->msize);
	if(n <= 0){
		fprint(2, "n = %d %F\n", n, &r->ofcall);
		abort();
	}
	assert(n > 2);
	/*
	 * There is a race here - we must remove the entry before
	 * the write, so that if the client is very fast and reuses the
	 * tag, the read loop won't think it is still in use.
	 * 
	 * By removing the entry before the write, we open up a 
	 * race with incoming Tflush messages.  Specifically, an
	 * incoming Tflush might not see r even though it has not
	 * yet been responded to.  It would then send an Rflush
	 * immediately, potentially before we do the write.  This can't
	 * happen because we already old srv->wlock, so nothing
	 * is going out on the wire before this write.
	 */
	if(r->pool)	/* not a fake */
		closereq(removereq(r->pool, r->ifcall.tag));

	qlock(&r->lk);
	r->responded = 1;
	if(r->pool)
	if(r->ref.ref == 1+r->nflush)
	if(r->fid){
		/*
		 * There are no references other than in our r->flush array,
		 * so no one else should be accessing r concurrently.
		 * Close the fid now, before responding to the message.
		 * 
		 * If the client is behaving (there are no outstanding T-messages
		 * that reference r->fid) and the message is a Tclunk or Tremove,
		 * then this closefid will call destroyfid.  
		 * 
		 * This means destroyfid can't piddle around 
		 * indefinitely (we're holding srv->wlock!), but it provides
		 * for tighter semantics as to when destroyfid is called.
		 *
		 * LANL has observed cases where waiting until after the write
		 * can delay a closefid on a Twrite for many 9P transactions,
		 * so that a handful of transactions can happen including a Tclunk
		 * and a Topen, and the original fid will still not be destroyed.
		 */
		closefid(r->fid);
		r->fid = nil;
	}
	qunlock(&r->lk);
	m = write(srv->outfd, srv->wbuf, n);
	if(m != n)
		sysfatal("lib9p srv: write %d returned %d on fd %d: %r", n, m, srv->outfd);
	qunlock(&srv->wlock);

free:
	qlock(&r->lk);	/* no one will add flushes now */

	for(i=0; i<r->nflush; i++){
		r->flush[i]->oldreq = nil;	/* so it doesn't try to lock us! */
		respond(r->flush[i], nil);
	}
	free(r->flush);
	r->flush = nil;
	r->nflush = 0;
	qunlock(&r->lk);

	if(r->pool)
		closereq(r);
	else
		free(r);
}
示例#2
0
文件: srv.c 项目: npe9/harvey
void
respond(Req *r, char *error)
{
	int i, m, n;
	char errbuf[ERRMAX];
	Srv *srv;

	srv = r->srv;
	assert(srv != nil);

	assert(r->responded == 0);
	r->error = error;

	switch(r->ifcall.type){
	default:
		assert(0);
	/*
	 * Flush is special.  If the handler says so, we return
	 * without further processing.  Respond will be called
	 * again once it is safe.
	 */
	case Tflush:
		if(rflush(r, error)<0)
			return;
		break;
	case Tversion:	rversion(r, error);	break;
	case Tauth:	rauth(r, error);	break;
	case Tattach:	rattach(r, error);	break;
	case Twalk:	rwalk(r, error);	break;
	case Topen:	ropen(r, error);	break;
	case Tcreate:	rcreate(r, error);	break;
	case Tread:	rread(r, error);	break;
	case Twrite:	rwrite(r, error);	break;
	case Tclunk:	rclunk(r, error);	break;
	case Tremove:	rremove(r, error, errbuf);	break;
	case Tstat:	rstat(r, error);	break;
	case Twstat:	rwstat(r, error);	break;
	}

	r->ofcall.tag = r->ifcall.tag;
	r->ofcall.type = r->ifcall.type+1;
	if(r->error)
		setfcallerror(&r->ofcall, r->error);

if(chatty9p)
	fprint(2, "-%d-> %F\n", srv->outfd, &r->ofcall);

	qlock(&srv->wlock);
	n = convS2M(&r->ofcall, srv->wbuf, srv->msize);
	if(n <= 0){
		fprint(2, "n = %d %F\n", n, &r->ofcall);
		abort();
	}
	assert(n > 2);
	if(r->pool)	/* not a fake */
		closereq(removereq(r->pool, r->ifcall.tag));
	m = write(srv->outfd, srv->wbuf, n);
	if(m != n)
		sysfatal("lib9p srv: write %d returned %d on fd %d: %r", n, m, srv->outfd);
	qunlock(&srv->wlock);

	qlock(&r->lk);	/* no one will add flushes now */
	r->responded = 1;
	qunlock(&r->lk);

	for(i=0; i<r->nflush; i++)
		respond(r->flush[i], nil);
	free(r->flush);
	r->flush = nil;
	r->nflush = 0;

	if(r->pool)
		closereq(r);
	else
		free(r);
}
示例#3
0
文件: dns.c 项目: Earnestly/plan9
void
io(void)
{
	volatile long n;
	volatile uchar mdata[IOHDRSZ + Maxfdata];
	Job *volatile job;
	Mfile *volatile mf;
	volatile Request req;

	memset(&req, 0, sizeof req);
	/*
	 *  a slave process is sometimes forked to wait for replies from other
	 *  servers.  The master process returns immediately via a longjmp
	 *  through 'mret'.
	 */
	if(setjmp(req.mret))
		putactivity(0);
	req.isslave = 0;
	stop = 0;
	while(!stop){
		procsetname("%d %s/dns Twrites of %d 9p rpcs read; %d alarms",
			stats.qrecvd9p, mntpt, stats.qrecvd9prpc, stats.alarms);
		n = read9pmsg(mfd[0], mdata, sizeof mdata);
		if(n<=0){
			dnslog("error reading 9P from %s: %r", mntpt);
			sleep(2000);	/* don't thrash after read error */
			return;
		}

		stats.qrecvd9prpc++;
		job = newjob();
		if(convM2S(mdata, n, &job->request) != n){
			freejob(job);
			continue;
		}
		mf = newfid(job->request.fid, 0);
		if(debug)
			dnslog("%F", &job->request);

		getactivity(&req, 0);
		req.aborttime = timems() + Maxreqtm;
		req.from = "9p";

		switch(job->request.type){
		default:
			warning("unknown request type %d", job->request.type);
			break;
		case Tversion:
			rversion(job);
			break;
		case Tauth:
			rauth(job);
			break;
		case Tflush:
			rflush(job);
			break;
		case Tattach:
			rattach(job, mf);
			break;
		case Twalk:
			rwalk(job, mf);
			break;
		case Topen:
			ropen(job, mf);
			break;
		case Tcreate:
			rcreate(job, mf);
			break;
		case Tread:
			rread(job, mf);
			break;
		case Twrite:
			/* &req is handed to dnresolve() */
			rwrite(job, mf, &req);
			break;
		case Tclunk:
			rclunk(job, mf);
			break;
		case Tremove:
			rremove(job, mf);
			break;
		case Tstat:
			rstat(job, mf);
			break;
		case Twstat:
			rwstat(job, mf);
			break;
		}

		freejob(job);

		/*
		 *  slave processes die after replying
		 */
		if(req.isslave){
			putactivity(0);
			_exits(0);
		}

		putactivity(0);
	}
	/* kill any udp server, notifier, etc. processes */
	postnote(PNGROUP, getpid(), "die");
	sleep(1000);
}
示例#4
0
文件: cs.c 项目: brho/akaros
static void *job_thread(void *arg)
{
	struct mfile *mf;
	struct job *job = arg;

	spinlock_lock(&dblock);
	mf = newfid(job->request.fid);

	if (debug)
		fprintf(stderr, "CS:%F", &job->request);
	switch (job->request.type) {
	default:
		fprintf(stderr, "CS:unknown request type %d", job->request.type);
		break;
	case Tversion:
		rversion(job);
		break;
	case Tauth:
		rauth(job);
		break;
	case Tflush:
		rflush(job);
		break;
	case Tattach:
		rattach(job, mf);
		break;
	case Twalk:
		rwalk(job, mf);
		break;
	case Topen:
		ropen(job, mf);
		break;
	case Tcreate:
		rcreate(job, mf);
		break;
	case Tread:
		rread(job, mf);
		break;
	case Twrite:
		rwrite(job, mf);
		break;
	case Tclunk:
		rclunk(job, mf);
		break;
	case Tremove:
		rremove(job, mf);
		break;
	case Tstat:
		rstat(job, mf);
		break;
	case Twstat:
		rwstat(job, mf);
		break;
	}
	spinlock_unlock(&dblock);

	freejob(job);

	if (debug)
		fprintf(stderr, "CS:Job done\n");
	return 0;
}
示例#5
0
文件: dns.c 项目: 00001/plan9port
void
ioproc0(void *v)
{
	long n;
	Mfile *mf;
	uchar mdata[IOHDRSZ + Maxfdata];
	Request req;
	Job *job;

	USED(v);

	for(;;){
		n = read9pmsg(mfd[0], mdata, sizeof mdata);
		if(n <= 0){
			syslog(0, logfile, "error reading mntpt: %r");
			break;
		}
		job = newjob();
		if(convM2S(mdata, n, &job->request) != n){
			freejob(job);
			continue;
		}
		if(debug)
			syslog(0, logfile, "%F", &job->request);

		getactivity(&req);
		req.aborttime = now + 60;	/* don't spend more than 60 seconds */

		mf = nil;
		switch(job->request.type){
		case Tversion:
		case Tauth:
		case Tflush:
			break;
		case Tattach:
			mf = newfid(job->request.fid, 1);
			if(mf == nil){
				sendmsg(job, "fid in use");
				goto skip;
			}
			break;
		default:
			mf = newfid(job->request.fid, 0);
			if(mf == nil){
				sendmsg(job, "unknown fid");
				goto skip;
			}
			break;
		}

		switch(job->request.type){
		default:
			syslog(1, logfile, "unknown request type %d", job->request.type);
			break;
		case Tversion:
			rversion(job);
			break;
		case Tauth:
			rauth(job);
			break;
		case Tflush:
			rflush(job);
			break;
		case Tattach:
			rattach(job, mf);
			break;
		case Twalk:
			rwalk(job, mf);
			break;
		case Topen:
			ropen(job, mf);
			break;
		case Tcreate:
			rcreate(job, mf);
			break;
		case Tread:
			rread(job, mf);
			break;
		case Twrite:
			rwrite(job, mf, &req);
			break;
		case Tclunk:
			rclunk(job, mf);
			break;
		case Tremove:
			rremove(job, mf);
			break;
		case Tstat:
			rstat(job, mf);
			break;
		case Twstat:
			rwstat(job, mf);
			break;
		}
skip:
		freejob(job);
		putactivity();
	}
}