1 /* Copyright (C) 2003 Russ Cox, Massachusetts Institute of Technology */
2 /* See COPYRIGHT */
3 
4 #include <u.h>
5 #include <libc.h>
6 #include <fcall.h>
7 #include <9pclient.h>
8 #include <thread.h>
9 #include "fsimpl.h"
10 
11 static int _fssend(Mux*, void*);
12 static void *_fsrecv(Mux*);
13 static int _fsgettag(Mux*, void*);
14 static int _fssettag(Mux*, void*, uint);
15 
16 enum
17 {
18 	CFidchunk = 32
19 };
20 
21 CFsys*
22 fsinit(int fd)
23 {
24 	CFsys *fs;
25 
26 	fmtinstall('F', fcallfmt);
27 	fmtinstall('D', dirfmt);
28 	fmtinstall('M', dirmodefmt);
29 
30 	fs = mallocz(sizeof(CFsys), 1);
31 	if(fs == nil)
32 		return nil;
33 	fs->fd = fd;
34 	fs->ref = 1;
35 	fs->mux.aux = fs;
36 	fs->mux.mintag = 0;
37 	fs->mux.maxtag = 256;
38 	fs->mux.send = _fssend;
39 	fs->mux.recv = _fsrecv;
40 	fs->mux.gettag = _fsgettag;
41 	fs->mux.settag = _fssettag;
42 	fs->iorecv = ioproc();
43 	fs->iosend = ioproc();
44 	muxinit(&fs->mux);
45 	return fs;
46 }
47 
48 CFid*
49 fsroot(CFsys *fs)
50 {
51 	/* N.B. no incref */
52 	return fs->root;
53 }
54 
55 CFsys*
56 fsmount(int fd, char *aname)
57 {
58 	int n;
59 	char *user;
60 	CFsys *fs;
61 	CFid *fid;
62 
63 	fs = fsinit(fd);
64 	if(fs == nil)
65 		return nil;
66 	strcpy(fs->version, "9P2000");
67 	if((n = fsversion(fs, 8192, fs->version, sizeof fs->version)) < 0){
68 	Error:
69 		fs->fd = -1;
70 		fsunmount(fs);
71 		return nil;
72 	}
73 	fs->msize = n;
74 
75 	user = getuser();
76 	if((fid = fsattach(fs, nil, getuser(), aname)) == nil)
77 		goto Error;
78 	fssetroot(fs, fid);
79 	return fs;
80 }
81 
82 void
83 fsunmount(CFsys *fs)
84 {
85 	fsclose(fs->root);
86 	fs->root = nil;
87 	_fsdecref(fs);
88 }
89 
90 void
91 _fsdecref(CFsys *fs)
92 {
93 	CFid *f, **l, *next;
94 
95 	qlock(&fs->lk);
96 	--fs->ref;
97 	//fprint(2, "fsdecref %p to %d\n", fs, fs->ref);
98 	if(fs->ref == 0){
99 		close(fs->fd);
100 		/* trim the list down to just the first in each chunk */
101 		for(l=&fs->freefid; *l; ){
102 			if((*l)->fid%CFidchunk == 0)
103 				l = &(*l)->next;
104 			else
105 				*l = (*l)->next;
106 		}
107 		/* now free the list */
108 		for(f=fs->freefid; f; f=next){
109 			next = f->next;
110 			free(f);
111 		}
112 		closeioproc(fs->iorecv);
113 		closeioproc(fs->iosend);
114 		free(fs);
115 		return;
116 	}
117 	qunlock(&fs->lk);
118 }
119 
120 int
121 fsversion(CFsys *fs, int msize, char *version, int nversion)
122 {
123 	void *freep;
124 	int r, oldmintag, oldmaxtag;
125 	Fcall tx, rx;
126 
127 	tx.tag = 0;
128 	tx.type = Tversion;
129 	tx.version = version;
130 	tx.msize = msize;
131 
132 	/*
133 	 * bit of a clumsy hack -- force libmux to use NOTAG as tag.
134 	 * version can only be sent when there are no other messages
135 	 * outstanding on the wire, so this is more reasonable than it looks.
136 	 */
137 	oldmintag = fs->mux.mintag;
138 	oldmaxtag = fs->mux.maxtag;
139 	fs->mux.mintag = NOTAG;
140 	fs->mux.maxtag = NOTAG+1;
141 	r = _fsrpc(fs, &tx, &rx, &freep);
142 	fs->mux.mintag = oldmintag;
143 	fs->mux.maxtag = oldmaxtag;
144 	if(r < 0)
145 		return -1;
146 
147 	strecpy(version, version+nversion, rx.version);
148 	free(freep);
149 	return rx.msize;
150 }
151 
152 CFid*
153 fsattach(CFsys *fs, CFid *afid, char *user, char *aname)
154 {
155 	Fcall tx, rx;
156 	CFid *fid;
157 
158 	if(aname == nil)
159 		aname = "";
160 
161 	if((fid = _fsgetfid(fs)) == nil)
162 		return nil;
163 
164 	tx.tag = 0;
165 	tx.type = Tattach;
166 	tx.afid = afid ? afid->fid : NOFID;
167 	tx.fid = fid->fid;
168 	tx.uname = user;
169 	tx.aname = aname;
170 
171 	if(_fsrpc(fs, &tx, &rx, 0) < 0){
172 		_fsputfid(fid);
173 		return nil;
174 	}
175 	fid->qid = rx.qid;
176 	return fid;
177 }
178 
179 void
180 fssetroot(CFsys *fs, CFid *fid)
181 {
182 	if(fs->root)
183 		_fsputfid(fs->root);
184 	fs->root = fid;
185 }
186 
187 int
188 _fsrpc(CFsys *fs, Fcall *tx, Fcall *rx, void **freep)
189 {
190 	int n, nn;
191 	void *tpkt, *rpkt;
192 
193 	n = sizeS2M(tx);
194 	tpkt = malloc(n);
195 	if(freep)
196 		*freep = nil;
197 	if(tpkt == nil)
198 		return -1;
199 	//fprint(2, "<- %F\n", tx);
200 	nn = convS2M(tx, tpkt, n);
201 	if(nn != n){
202 		free(tpkt);
203 		werrstr("libfs: sizeS2M convS2M mismatch");
204 		fprint(2, "%r\n");
205 		return -1;
206 	}
207 	rpkt = muxrpc(&fs->mux, tpkt);
208 	free(tpkt);
209 	if(rpkt == nil)
210 		return -1;
211 	n = GBIT32((uchar*)rpkt);
212 	nn = convM2S(rpkt, n, rx);
213 	if(nn != n){
214 		free(rpkt);
215 		werrstr("libfs: convM2S packet size mismatch %d %d", n, nn);
216 		fprint(2, "%r\n");
217 		return -1;
218 	}
219 	//fprint(2, "-> %F\n", rx);
220 	if(rx->type == Rerror){
221 		werrstr("%s", rx->ename);
222 		free(rpkt);
223 		return -1;
224 	}
225 	if(rx->type != tx->type+1){
226 		werrstr("packet type mismatch -- tx %d rx %d",
227 			tx->type, rx->type);
228 		free(rpkt);
229 		return -1;
230 	}
231 	if(freep)
232 		*freep = rpkt;
233 	else
234 		free(rpkt);
235 	return 0;
236 }
237 
238 CFid*
239 _fsgetfid(CFsys *fs)
240 {
241 	int i;
242 	CFid *f;
243 
244 	qlock(&fs->lk);
245 	if(fs->freefid == nil){
246 		f = mallocz(sizeof(CFid)*CFidchunk, 1);
247 		if(f == nil){
248 			qunlock(&fs->lk);
249 			return nil;
250 		}
251 		for(i=0; i<CFidchunk; i++){
252 			f[i].fid = fs->nextfid++;
253 			f[i].next = &f[i+1];
254 			f[i].fs = fs;
255 		}
256 		f[i-1].next = nil;
257 		fs->freefid = f;
258 	}
259 	f = fs->freefid;
260 	fs->freefid = f->next;
261 	fs->ref++;
262 	qunlock(&fs->lk);
263 	return f;
264 }
265 
266 void
267 _fsputfid(CFid *f)
268 {
269 	CFsys *fs;
270 
271 	fs = f->fs;
272 	qlock(&fs->lk);
273 	f->next = fs->freefid;
274 	fs->freefid = f;
275 	qunlock(&fs->lk);
276 	_fsdecref(fs);
277 }
278 
279 static int
280 _fsgettag(Mux *mux, void *pkt)
281 {
282 	return GBIT16((uchar*)pkt+5);
283 }
284 
285 static int
286 _fssettag(Mux *mux, void *pkt, uint tag)
287 {
288 	PBIT16((uchar*)pkt+5, tag);
289 	return 0;
290 }
291 
292 static int
293 _fssend(Mux *mux, void *pkt)
294 {
295 	CFsys *fs;
296 
297 	fs = mux->aux;
298 	return iowrite(fs->iosend, fs->fd, pkt, GBIT32((uchar*)pkt));
299 }
300 
301 static void*
302 _fsrecv(Mux *mux)
303 {
304 	uchar *pkt;
305 	uchar buf[4];
306 	int n, nfd;
307 	CFsys *fs;
308 
309 	fs = mux->aux;
310 	n = ioreadn(fs->iorecv, fs->fd, buf, 4);
311 	if(n != 4)
312 		return nil;
313 	n = GBIT32(buf);
314 	pkt = malloc(n+4);
315 	if(pkt == nil){
316 		fprint(2, "libfs out of memory reading 9p packet; here comes trouble\n");
317 		return nil;
318 	}
319 	PBIT32(pkt, n);
320 	if(ioreadn(fs->iorecv, fs->fd, pkt+4, n-4) != n-4){
321 		free(pkt);
322 		return nil;
323 	}
324 	if(pkt[4] == Ropenfd){
325 		if((nfd=iorecvfd(fs->iorecv, fs->fd)) < 0){
326 			fprint(2, "recv fd error: %r\n");
327 			free(pkt);
328 			return nil;
329 		}
330 		PBIT32(pkt+n-4, nfd);
331 	}
332 	return pkt;
333 }