shithub: ridefs

ref: 8e6a699a50caaa038d45ff8db473bb7059cb2947
dir: /ridefs.c/

#include <u.h>
#include <libc.h>
#include <fcall.h>
#include <thread.h>
#include <9p.h>
#include <stdio.h>
#include <json.h>


typedef struct Client Client;
typedef struct Rfid Rfid;

struct Client {
	Ref;

	char *addr;

	/* tcp i/o */
	QLock rl, wl;
	Req *rreq, *wreq;
	int rpid, wpid;
	int fd, cfd;

	/* buffers */
	char *qinfo, *qctl;
	char *r;      /* response */
	int rn, roff;
};

enum {
	Qroot,
		Qrctl,
		Qclone,
		Qclient,
			Qctl,
			Qdata,
			Qinfo,
	QCOUNT
};

static char *nametab[] = {
	"/",
		"ctl",
		"clone",
		nil,
			"ctl",
			"data",
			"info",
};

struct Rfid {
	Ref;
	int kind;
	int client;
};

#define VERSION 0
static Client *cpool;
static char *mtpt;
static char *service;
static char *defport;
static char *user;
static char *qrctl;
static long bufsz;
static long time0;
static uint nclients;
static int debug;

void*
ecalloc(ulong n){
	void *p;

	p = emalloc9p(n);
	setmalloctag(p, getcallerpc(&n));
	memset(p, 0, n);

	return p;
}

void*
erealloc(void *p, ulong n){
	p = erealloc9p(p, n);
	setrealloctag(p, getcallerpc(&n));
	return p;
}

char*
estrdup(char *s){
	if(s == nil)
		return nil;

	s = estrdup9p(s);
	setrealloctag(s, getcallerpc(&s));
	return s;
}

Client*
clientref(int i){
	if(i < 0 || i > nclients)
		return nil;
	return &cpool[i];
}

int
genqrctl(void){
	snprintf(qrctl, bufsz,
		"version %i\n"
		"bufsz %u\n"
		"nclients %u\n"
		"debug %i\n"
		"defport %s\n",
		VERSION, bufsz, nclients, debug,defport);

	return strlen(qrctl);
}

int
genqctl(int client){
	Client *c;

	c = clientref(client);
	snprintf(c->qctl, bufsz,
		"%i\n"
		"connect %s\n",
		client, c->addr);

	return strlen(c->qctl);
}

int
mkclient(void){
	Client *c;
	int i;

	for(i = 0; i < nclients; i++)
		if(cpool[i].ref == 0)
			break;
	if(i == nclients)
		return -1;
	c = &cpool[i];

	incref(c);
	c->r = ecalloc(bufsz);
	c->rn = -1;
	c->qctl = ecalloc(bufsz);
	c->qinfo = ecalloc(bufsz);
	genqctl(i);

	return i;
}

void
rmclient(int i){
	Client *c;

	c = clientref(i);
	if(c == nil || decref(c))
		return;
		
	if(c->fd) close(c->fd);
	if(c->cfd) close(c->cfd);
	if(c->qctl) free(c->qctl);
	if(c->qinfo) free(c->qinfo);
	if(c->r) free(c->r);

	memset(c, 0, sizeof(*c));
}

static void
mkqid(Qid *q, int k, int client){
	q->vers = VERSION;
	q->path = ((u64int)client<<32) | k&0xffffffff;

	switch(k){
	case Qroot:
	case Qclient:
		q->type = QTDIR; break;
	default:
		q->type = QTFILE;
	}
}

long
writemsg(int fd, void *pld, long n){
	char *r;
	int len;

	len = n+8;
	r = ecalloc(len);
	r[0] = 24>>len & 0xff;
	r[1] = 16>>len & 0xff;
	r[2] =  8>>len & 0xff;
	r[3] =     len & 0xff;
	r[4] = 'R';
	r[5] = 'I';
	r[6] = 'D';
	r[7] = 'E';
	memcpy(&r[8], pld, n);
	write(fd, r, len);

	return n;
}

long
readmsg(int fd, void **pld){
	int len, e;
	char buf[9];

	if(0 > (e = readn(fd, buf, 8)))
		return e;

	buf[9] = '\0';
	if(0 != (e = strcmp(&buf[4], "RIDE")))
		return e;

	len = -8 + (buf[0]<<24 | buf[1]<<16 | buf[2]<<8 | buf[3]);
	*pld = ecalloc(len+1); /* ensure trailing null byte */
	if(0 > (e = readn(fd, *pld, len))){
		free(*pld);
		return e;
	}

	return len;
}

char *
rideinit(char *addr, int *fd, int *cfd, char **info){
	int i;
	char *b;
	JSON *j, *v;
	JSONEl *d;

	b = netmkaddr(addr, "tcp", defport);
	if(debug)
		fprintf(stderr, "dialing %s\n", addr);
	if((*fd = dial(b, nil, nil, cfd)) < 0)
		return "failed to dial";

	if(0 > readmsg(*fd, &b))
		return "failed to read handshake";
	if(0 != strcmp(b, "SupportedProtocols=2"))
		return "unrecognized protocol";
	free(b);

	b = "UsingProtocol=2";
	if(0 > writemsg(*fd, b, strlen(b)))
		return "failed to write handshake";
		
	b = "[\"Identify\",{\"apiVersion\":1,\"identity\":1}]";
	if(0 > writemsg(*fd, b, strlen(b)))
		return "failed to send identification message";

	if(0 > readmsg(*fd, &b))
		return "failed to receive identification message";
	if(nil == (j = jsonparse(b)))
		return "failed to parse identification message";
	free(b);
	if(j == nil || j->t != JSONArray || nil == j->first)
		return "unrecognized reply";
	v = j->first->val;
	if(v->t != JSONString || 0 != strcmp(v->s, "ReplyIdentify"))
		return "unexpected identification reply";
	if(nil == (d = j->first->next) || d->val->t != JSONObject)
		return "malformed identification reply";

	for(i = 0, d = d->val->first; d != nil; d = d->next){
		switch(d->val->t){
		case JSONBool:
		case JSONNumber:
			i += snprintf(*info+i, bufsz-i, "%s %i\n", d->name, d->val->n); break;
		case JSONString:
			i += snprintf(*info+i, bufsz-i, "%s %s\n", d->name, d->val->s); break;
		}
	}

	jsonfree(j);
	return nil;
}

long
writeqrctl(char *b, long){
	char *s;
	char sep[7];

	sprintf(sep, " \t\n\f\r\v");
	for(s = strtok(b, sep); s != nil; s = strtok(nil, sep)){
		if(strcmp(s, "bufsz") == 0)
			bufsz = strtoul(strtok(nil, sep), nil, 0);
		if(strcmp(s, "nclients") == 0)
			nclients = strtoul(strtok(nil, sep), nil, 0);
		if(strcmp(s, "debug") == 0)
			debug = atoi(strtok(nil, sep));
		if(strcmp(s, "defport") == 0)
			defport = estrdup(strtok(nil, sep));
	}

	cpool = erealloc(cpool, nclients*sizeof(*cpool));
	genqrctl();

	return strlen(qrctl);
}

long
writeqctl(char *b, long n, int client){
	Client *c;
	char *s, sep[7];

	c = clientref(client);
	sprintf(sep, " \t\n\f\r\v");
	for(s = strtok(b, sep); s != nil; s = strtok(nil, sep)){
		if(strcmp(s, "connect") == 0)
			c->addr = estrdup(strtok(nil, sep));
	}

	genqctl(client);

	return n;
}

void
mkdirent(Dir *d, int kind, int client){
	Client *c;
	char *nm;

	memset(d, 0, sizeof(*d));
	mkqid(&d->qid, kind, client);
	d->mode = 0444;
	d->atime = d->mtime = time0;
	d->uid = estrdup(user);
	d->gid = estrdup(user);
	d->muid = estrdup(user);
	if(nil != (nm = nametab[kind]))
		d->name = estrdup(nm);
	if(kind == Qclient){
		nm = ecalloc(client+2); /* client+1 >= log(client) */
		sprintf(nm, "%i", client);
		d->name = estrdup(nm);
	}
	if(d->qid.type & QTDIR)
		d->mode |= DMDIR | 0111;

	c = clientref(client);
	switch(kind){
	case Qrctl:   d->mode = 0666; break;
	case Qctl:
	case Qdata:     d->mode = 0666; break;
	}

	switch(kind){
	case Qrctl: d->length = strlen(qrctl); break;
	case Qctl: d->length = strlen(c->qctl); break;
	case Qdata: d->length = 0; break;
	case Qinfo: d->length = strlen(c->qinfo); break;
	}
}

int
genqroot(int i, Dir *d, void*){
	static int n;
	int j;

	i += Qroot + 1;
	if(i < Qclient){
		mkdirent(d, i, -1);
	} else {
		i -= Qclient;
		if(i == 0)
			n = 0;
		for(j = n; j < nclients && cpool[j].ref == 0; j++);
		if(j == nclients)
			return -1;
		n++;
		mkdirent(d, Qclient, j);
	}

	return 0;
}

int
genqclient(int i, Dir *d, void *aux){
	int client;

	client = (vlong)aux;
	i += Qclient + 1;
	if(i >= QCOUNT)
		return -1;
	mkdirent(d, i, client);
	return 0;
}

static void
fsdestroyfid(Fid *fid){
	Rfid *f;

	f = fid->aux;
	if(f == nil)
		return;

	rmclient(f->client);
	free(f);
}

static void
fsstart(Srv*){
	if(mtpt != nil)
		unmount(nil, mtpt);
}

static void
fsend(Srv*){
	postnote(PNGROUP, getpid(), "shutdown");
	exits(nil);
}

static void
fsattach(Req *r){
	Rfid *f;

	f = ecalloc(sizeof(*f));
	f->kind = Qroot;
	f->client = -1;

	mkqid(&r->fid->qid, f->kind, f->client);
	r->fid->aux = f;
	r->ofcall.qid = r->fid->qid;

	respond(r, nil);
}

static void
fsopen(Req *r){
	char *err;
	Rfid *f;
	Client *c;

	f = r->fid->aux;
	c = clientref(f->client);
	err = nil;
	switch(f->kind){
	case Qclone:
		if((f->client = mkclient()) == -1){
			respond(r, "reached client limit");
			return;
		}

		f->kind = Qctl;

		mkqid(&r->ofcall.qid, f->kind, f->client);
		r->fid->qid = r->ofcall.qid;

		respond(r, nil);
		break;
	case Qdata:
		if(nil == c->addr){
			respond(r, "no server set");
			return;
		}

		qlock(&c->wl);
		incref(&r->ref);
		c->wreq = r;
		switch(c->wpid = rfork(RFPROC|RFNOWAIT|RFMEM)){
		case 0:
			if(!c->fd)
				err = rideinit(c->addr, &c->fd, &c->cfd, &c->qinfo);
			c->wpid = 0;
			c->wreq = nil;
			decref(&r->ref);
			respond(r, err);
			qunlock(&c->wl);
			exits(nil);
		case -1:
			respond(r, "failed to init ride");
			c->wpid = 0;
			c->wreq = nil;
			decref(&r->ref);
			qunlock(&c->wl);
			break;
		default:
			return;
		}
		break;
	default:
		respond(r, nil);
	}
}

static void
fsread(Req *r){
	Rfid *f;
	Client *c;
	char *buf, *err;
	int n, off;

	buf = err = nil;
	f = r->fid->aux;
	c = clientref(f->client);
	switch(f->kind){
	case Qroot: dirread9p(r, genqroot, nil); break;
	case Qrctl: buf = estrdup(qrctl); break;
	case Qclone: err = "read prohibited"; break;
	case Qclient: dirread9p(r, genqclient, (void*)f->client); break;
	case Qctl: buf = estrdup(c->qctl); break;
	case Qinfo: buf = estrdup(c->qinfo); break;
	case Qdata:
		qlock(&c->rl);
		incref(&r->ref);
		c->rreq = r;
		switch(c->rpid = rfork(RFPROC|RFNOWAIT|RFMEM)){
		case 0:
			off = r->ifcall.offset - c->roff;
			if(c->rn < 0){
				free(c->r);
				c->r = nil;
				c->rn = readmsg(c->fd, &c->r);
				c->roff = r->ifcall.offset;
				off = 0;
			}

			n = r->ifcall.count + off < c->rn ?
				r->ifcall.count : c->rn - off;
			if(c->rn == off) {
				r->ofcall.count = 0;
				c->rn = -1;
			} else {
				memmove(r->ofcall.data, c->r + off, n);
				r->ofcall.count = n;
			}

			c->rpid = 0;
			c->rreq = nil;
			decref(&r->ref);
			respond(r, err);
			qunlock(&c->rl);
			exits(nil);
		case -1:
			err = "failed to fork read";
			c->rpid = 0;
			c->rreq = nil;
			decref(&r->ref);
			qunlock(&c->rl);
			break;
		default:
			return;
		}
		break;
	}

	if(buf != nil){
		readstr(r, buf);
		free(buf);
	}

	respond(r, err);
}

static void
fswrite(Req *r){
	Rfid *f;
	Client *c;
	char *d, *err;
	long n;

	d = r->ifcall.data;
	n = r->ifcall.count;
	f = r->fid->aux;
	c = clientref(f->client);
	err = nil;

	switch(f->kind){
	case Qrctl:
		r->ofcall.count = writeqrctl(d, n);
		break;
	case Qctl:
		r->ofcall.count = writeqctl(d, n, f->client);
		break;
	case Qdata:
		qlock(&c->wl);
		incref(&r->ref);
		c->wreq = r;
		switch(c->wpid = rfork(RFPROC|RFNOWAIT|RFMEM)){
		case 0:
			r->ofcall.count = writemsg(c->fd, d, n);

			c->wpid = 0;
			c->wreq = nil;
			decref(&r->ref);
			respond(r, nil);
			qunlock(&c->wl);
			exits(nil);
		case -1:
			err = "failed to fork write";
			c->wpid = 0;
			c->wreq = nil;
			decref(&r->ref);
			qunlock(&c->wl);
			break;
		default:
			return;
		}
		break;
	default:
		err = "write prohibited";
	}

	respond(r, err);
}

static void
fsflush(Req *r){
	Req *o;
	Rfid *f;
	Client *c;

	if(o = r->oldreq)
	if(f = o->fid->aux)
	if(c = clientref(f->client))
	if(o == c->rreq){
		postnote(PNPROC, c->rpid, "interrupt");
		respond(c->rreq, "interrupted");
		c->rpid = 0;
		decref(&c->rreq->ref);
		qunlock(&c->rl);
	} else if (o == c->wreq){
		postnote(PNPROC, c->wpid, "interrupt");
		respond(c->wreq, "interrupted");
		c->wpid = 0;
		c->wreq = nil;
		decref(&c->wreq->ref);
		qunlock(&c->wl);
	}

	respond(r, nil);
}

static void
fsstat(Req *r){
	Rfid *f;

	f = r->fid->aux;
	mkdirent(&r->d, f->kind, f->client);

	respond(r, nil);
}

static char*
fswalk1(Fid *fid, char *name, Qid *qid){
	Rfid *f;
	Client *c;
	int i, n;
	char *nend;

	if(!(fid->qid.type&QTDIR))
		return "cannot walk from non-directory";

	f = fid->aux;
	n = -1;
	if(strcmp(name, "..") == 0){
		switch(f->kind){
		case Qroot:
			break;
		case Qclient:
			rmclient(f->client);
			f->client = -1;
			break;
		default:
			if(f->kind > Qclient)
				f->kind = Qclient;
		}
	} else {
		for(i = f->kind+1; i<QCOUNT; i++){
			if(nametab[i] && strcmp(name, nametab[i]) == 0)
				break;
			if(i == Qclient){
				n = strtol(name, &nend, 10);
				c = clientref(n);
				if(*nend == 0 && c != nil && c->ref != 0){
					incref(c);
					f->client = n;
					break;
				}	
			}
		}
		if(i >= QCOUNT)
			return "directory entry not found";
		f->kind = i;
	}
	mkqid(qid, f->kind, n);
	fid->qid = *qid;
	return nil;
}

static char*
fsclone(Fid *oldfid, Fid *newfid){
	Rfid *f, *o;

	o = oldfid->aux;
	if(o == nil)
		return "bad fid";

	f = ecalloc(sizeof(*f));
	memmove(f, o, sizeof(*f));

	if(f->client > -1)
		incref(clientref(f->client));
	newfid->aux = f;

	return nil;
}

Srv fs = {
	.destroyfid = fsdestroyfid,
	.start      = fsstart,
	.end        = fsend,
	.attach     = fsattach,
	.open       = fsopen,
	.read       = fsread,
	.write      = fswrite,
	.flush      = fsflush,
	.stat       = fsstat,
	.walk1      = fswalk1,
	.clone      = fsclone,
};

void
usage(void){
	fprintf(stderr, "usage: %s [-Dd] [-m mtpt] [-s service]\n", argv0);
}

void
main(int argc, char **argv){
	user = getuser();
	mtpt = "/mnt/ride";
	defport = "4502";
	bufsz = 4096;
	time0 = time(0);
	nclients = 256;

	ARGBEGIN{
	case 'D': chatty9p++; break;
	case 'd': debug++; break;
	case 'm': mtpt = EARGF(usage()); break;
	case 's': service = EARGF(usage()); break;
	default:  usage(); return;
	}ARGEND

	cpool = ecalloc(nclients*sizeof(*cpool));
	qrctl = ecalloc(bufsz);
	genqrctl();

	JSONfmtinstall();

	if(debug)
		fprintf(stderr,
			"ridefs:\n"
			"\tchatty9p = %i\n"
			"\tdebug = %i\n"
			"\tmtpt = %s\n"
			"\tservice = %s\n"
			"\tdefport = %s\n"
			"\tfs = %p\n"
			"\tcpool = %p\n",
			chatty9p, debug, mtpt, service,
			defport, &fs, cpool);

	rfork(RFNOTEG);
	postmountsrv(&fs, service, mtpt, MREPL);
	exits(nil);
}