Subversion Repositories planix.SVN

/*

 * exportfs - Export a plan 9 name space across a network

 */

#include <u.h>

#include <libc.h>

#include <fcall.h>

#include <libsec.h>

#include "drawterm.h"

#define Extern

#include "exportfs.h"

/* #define QIDPATH	((1LL<<48)-1) */

#define QIDPATH	((((vlong)1)<<48)-1)

vlong newqid = 0;

void (*fcalls[256])(Fsrpc*);

/* accounting and debugging counters */

int	filecnt;

int	freecnt;

int	qidcnt;

int	qfreecnt;

int	ncollision;

int	netfd;

int

exportfs(int fd, int msgsz)

{

	char buf[ERRMAX], ebuf[ERRMAX];

	Fsrpc *r;

	int i, n;

	fcalls[Tversion] = Xversion;

	fcalls[Tauth] = Xauth;

	fcalls[Tflush] = Xflush;

	fcalls[Tattach] = Xattach;

	fcalls[Twalk] = Xwalk;

	fcalls[Topen] = slave;

	fcalls[Tcreate] = Xcreate;

	fcalls[Tclunk] = Xclunk;

	fcalls[Tread] = slave;

	fcalls[Twrite] = slave;

	fcalls[Tremove] = Xremove;

	fcalls[Tstat] = Xstat;

	fcalls[Twstat] = Xwstat;

	srvfd = -1;

	netfd = fd;

	//dbg = 1;

	strcpy(buf, "this is buf");

	strcpy(ebuf, "this is ebuf");

	DEBUG(DFD, "exportfs: started\n");

//	rfork(RFNOTEG);

	messagesize = msgsz;

	if(messagesize == 0){

		messagesize = iounit(netfd);

		if(messagesize == 0)

			messagesize = 8*8192+IOHDRSZ;

	}

	Workq = emallocz(sizeof(Fsrpc)*Nr_workbufs);

//	for(i=0; i<Nr_workbufs; i++)

//		Workq[i].buf = emallocz(messagesize);

	fhash = emallocz(sizeof(Fid*)*FHASHSIZE);

	fmtinstall('F', fcallfmt);

	initroot();

	DEBUG(DFD, "exportfs: %s\n", buf);

	/*

	 * Start serving file requests from the network

	 */

	for(;;) {

		r = getsbuf();

		if(r == 0)

			fatal("Out of service buffers");

		DEBUG(DFD, "read9p...");

		n = read9pmsg(netfd, r->buf, messagesize);

		if(n <= 0)

			fatal("eof: n=%d %r", n);

		if(convM2S(r->buf, n, &r->work) == 0){

			iprint("convM2S %d byte message\n", n);

			for(i=0; i<n; i++){

				iprint(" %.2ux", r->buf[i]);

				if(i%16 == 15)

					iprint("\n");

			}

			if(i%16)

				iprint("\n");

			fatal("convM2S format error");

		}

if(0) iprint("<- %F\n", &r->work);

		DEBUG(DFD, "%F\n", &r->work);

		(fcalls[r->work.type])(r);

	}

}

void

reply(Fcall *r, Fcall *t, char *err)

{

	uchar *data;

	int m, n;

	t->tag = r->tag;

	t->fid = r->fid;

	if(err) {

		t->type = Rerror;

		t->ename = err;

	}

	else 

		t->type = r->type + 1;

if(0) iprint("-> %F\n", t);

	DEBUG(DFD, "\t%F\n", t);

	data = malloc(messagesize);	/* not mallocz; no need to clear */

	if(data == nil)

		fatal(Enomem);

	n = convS2M(t, data, messagesize);

	if((m=write(netfd, data, n))!=n){

		iprint("wrote %d got %d (%r)\n", n, m);

		fatal("write");

	}

	free(data);

}

Fid *

getfid(int nr)

{

	Fid *f;

	for(f = fidhash(nr); f; f = f->next)

		if(f->nr == nr)

			return f;

	return 0;

}

int

freefid(int nr)

{

	Fid *f, **l;

	char buf[128];

	l = &fidhash(nr);

	for(f = *l; f; f = f->next) {

		if(f->nr == nr) {

			if(f->mid) {

				sprint(buf, "/mnt/exportfs/%d", f->mid);

				unmount(0, buf);

				psmap[f->mid] = 0;

			}

			if(f->f) {

				freefile(f->f);

				f->f = nil;

			}

			*l = f->next;

			f->next = fidfree;

			fidfree = f;

			return 1;

		}

		l = &f->next;

	}

	return 0;	

}

Fid *

newfid(int nr)

{

	Fid *new, **l;

	int i;

	l = &fidhash(nr);

	for(new = *l; new; new = new->next)

		if(new->nr == nr)

			return 0;

	if(fidfree == 0) {

		fidfree = emallocz(sizeof(Fid) * Fidchunk);

		for(i = 0; i < Fidchunk-1; i++)

			fidfree[i].next = &fidfree[i+1];

		fidfree[Fidchunk-1].next = 0;

	}

	new = fidfree;

	fidfree = new->next;

	memset(new, 0, sizeof(Fid));

	new->next = *l;

	*l = new;

	new->nr = nr;

	new->fid = -1;

	new->mid = 0;

	return new;	

}

Fsrpc *

getsbuf(void)

{

	static int ap;

	int look, rounds;

	Fsrpc *wb;

	int small_instead_of_fast = 1;

	if(small_instead_of_fast)

		ap = 0;	/* so we always start looking at the beginning and reuse buffers */

	for(rounds = 0; rounds < 10; rounds++) {

		for(look = 0; look < Nr_workbufs; look++) {

			if(++ap == Nr_workbufs)

				ap = 0;

			if(Workq[ap].busy == 0)

				break;

		}

		if(look == Nr_workbufs){

			sleep(10 * rounds);

			continue;

		}

		wb = &Workq[ap];

		wb->pid = 0;

		wb->canint = 0;

		wb->flushtag = NOTAG;

		wb->busy = 1;

		if(wb->buf == nil)	/* allocate buffers dynamically to keep size down */

			wb->buf = emallocz(messagesize);

		return wb;

	}

	fatal("No more work buffers");

	return nil;

}

void

freefile(File *f)

{

	File *parent, *child;

Loop:

	f->ref--;

	if(f->ref > 0)

		return;

	freecnt++;

	if(f->ref < 0) abort();

	DEBUG(DFD, "free %s\n", f->name);

	/* delete from parent */

	parent = f->parent;

	if(parent->child == f)

		parent->child = f->childlist;

	else{

		for(child=parent->child; child->childlist!=f; child=child->childlist)

			if(child->childlist == nil)

				fatal("bad child list");

		child->childlist = f->childlist;

	}

	freeqid(f->qidt);

	free(f->name);

	f->name = nil;

	free(f);

	f = parent;

	if(f != nil)

		goto Loop;

}

File *

file(File *parent, char *name)

{

	Dir *dir;

	char *path;

	File *f;

	DEBUG(DFD, "\tfile: 0x%p %s name %s\n", parent, parent->name, name);

	path = makepath(parent, name);

	dir = dirstat(path);

	free(path);

	if(dir == nil)

		return nil;

	for(f = parent->child; f; f = f->childlist)

		if(strcmp(name, f->name) == 0)

			break;

	if(f == nil){

		f = emallocz(sizeof(File));

		f->name = estrdup(name);

		f->parent = parent;

		f->childlist = parent->child;

		parent->child = f;

		parent->ref++;

		f->ref = 0;

		filecnt++;

	}

	f->ref++;

	f->qid.type = dir->qid.type;

	f->qid.vers = dir->qid.vers;

	f->qidt = uniqueqid(dir);

	f->qid.path = f->qidt->uniqpath;

	f->inval = 0;

	free(dir);

	return f;

}

void

initroot(void)

{

	Dir *dir;

	root = emallocz(sizeof(File));

	root->name = estrdup(".");

	dir = dirstat(root->name);

	if(dir == nil)

		fatal("root stat");

	root->ref = 1;

	root->qid.vers = dir->qid.vers;

	root->qidt = uniqueqid(dir);

	root->qid.path = root->qidt->uniqpath;

	root->qid.type = QTDIR;

	free(dir);

	psmpt = emallocz(sizeof(File));

	psmpt->name = estrdup("/");

	dir = dirstat(psmpt->name);

	if(dir == nil)

		return;

	psmpt->ref = 1;

	psmpt->qid.vers = dir->qid.vers;

	psmpt->qidt = uniqueqid(dir);

	psmpt->qid.path = psmpt->qidt->uniqpath;

	free(dir);

	psmpt = file(psmpt, "mnt");

	if(psmpt == 0)

		return;

	psmpt = file(psmpt, "exportfs");

}

char*

makepath(File *p, char *name)

{

	int i, n;

	char *c, *s, *path, *seg[256];

	seg[0] = name;

	n = strlen(name)+2;

	for(i = 1; i < 256 && p; i++, p = p->parent){

		seg[i] = p->name;

		n += strlen(p->name)+1;

	}

	path = malloc(n);

	if(path == nil)

		fatal("out of memory");

	s = path;

	while(i--) {

		for(c = seg[i]; *c; c++)

			*s++ = *c;

		*s++ = '/';

	}

	while(s[-1] == '/')

		s--;

	*s = '\0';

	return path;

}

int

qidhash(vlong path)

{

	int h, n;

	h = 0;

	for(n=0; n<64; n+=Nqidbits){

		h ^= path;

		path >>= Nqidbits;

	}

	return h & (Nqidtab-1);

}

void

freeqid(Qidtab *q)

{

	ulong h;

	Qidtab *l;

	q->ref--;

	if(q->ref > 0)

		return;

	qfreecnt++;

	h = qidhash(q->path);

	if(qidtab[h] == q)

		qidtab[h] = q->next;

	else{

		for(l=qidtab[h]; l->next!=q; l=l->next)

			if(l->next == nil)

				fatal("bad qid list");

		l->next = q->next;

	}

	free(q);

}

Qidtab*

qidlookup(Dir *d)

{

	ulong h;

	Qidtab *q;

	h = qidhash(d->qid.path);

	for(q=qidtab[h]; q!=nil; q=q->next)

		if(q->type==d->type && q->dev==d->dev && q->path==d->qid.path)

			return q;

	return nil;

}

int

qidexists(vlong path)

{

	int h;

	Qidtab *q;

	for(h=0; h<Nqidtab; h++)

		for(q=qidtab[h]; q!=nil; q=q->next)

			if(q->uniqpath == path)

				return 1;

	return 0;

}

Qidtab*

uniqueqid(Dir *d)

{

	ulong h;

	vlong path;

	Qidtab *q;

	q = qidlookup(d);

	if(q != nil){

		q->ref++;

		return q;

	}

	path = d->qid.path;

	while(qidexists(path)){

		DEBUG(DFD, "collision on %s\n", d->name);

		/* collision: find a new one */

		ncollision++;

		path &= QIDPATH;

		++newqid;

		if(newqid >= (1<<16)){

			DEBUG(DFD, "collision wraparound\n");

			newqid = 1;

		}

		path |= newqid<<48;

		DEBUG(DFD, "assign qid %.16llux\n", path);

	}

	q = mallocz(sizeof(Qidtab), 1);

	if(q == nil)

		fatal("no memory for qid table");

	qidcnt++;

	q->ref = 1;

	q->type = d->type;

	q->dev = d->dev;

	q->path = d->qid.path;

	q->uniqpath = path;

	h = qidhash(d->qid.path);

	q->next = qidtab[h];

	qidtab[h] = q;

	return q;

}

void

fatal(char *s, ...)

{

	char buf[ERRMAX];

	va_list arg;

	if (s) {

		va_start(arg, s);

		vsnprint(buf, ERRMAX, s, arg);

		va_end(arg);

	}

	/* Clear away the slave children */

//	for(m = Proclist; m; m = m->next)

//		postnote(PNPROC, m->pid, "kill");

	DEBUG(DFD, "%s\n", buf);

	if (s) 

		sysfatal(buf);

	else

		sysfatal("");

}