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 <fs.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 	Fidchunk = 32
19 };
20 
21 Fsys*
22 fsinit(int fd)
23 {
24 	Fsys *fs;
25 
26 	fmtinstall('F', fcallfmt);
27 	fmtinstall('D', dirfmt);
28 	fmtinstall('M', dirmodefmt);
29 
30 	fs = mallocz(sizeof(Fsys), 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 	muxinit(&fs->mux);
43 	return fs;
44 }
45 
46 Fid*
47 fsroot(Fsys *fs)
48 {
49 	/* N.B. no incref */
50 	return fs->root;
51 }
52 
53 Fsys*
54 fsmount(int fd, char *aname)
55 {
56 	int n;
57 	char *user;
58 	Fsys *fs;
59 
60 	fs = fsinit(fd);
61 	if(fs == nil)
62 		return nil;
63 	strcpy(fs->version, "9P2000");
64 	if((n = fsversion(fs, 8192, fs->version, sizeof fs->version)) < 0){
65 	Error:
66 		fs->fd = -1;
67 		fsunmount(fs);
68 		return nil;
69 	}
70 	fs->msize = n;
71 
72 	user = getuser();
73 	if((fs->root = fsattach(fs, nil, getuser(), aname)) == nil)
74 		goto Error;
75 	return fs;
76 }
77 
78 void
79 fsunmount(Fsys *fs)
80 {
81 	fsclose(fs->root);
82 	fs->root = nil;
83 	_fsdecref(fs);
84 }
85 
86 void
87 _fsdecref(Fsys *fs)
88 {
89 	Fid *f, *next;
90 
91 	qlock(&fs->lk);
92 	--fs->ref;
93 	//fprint(2, "fsdecref %p to %d\n", fs, fs->ref);
94 	if(fs->ref == 0){
95 		close(fs->fd);
96 		for(f=fs->freefid; f; f=next){
97 			next = f->next;
98 			if(f->fid%Fidchunk == 0)
99 				free(f);
100 		}
101 		free(fs);
102 	}
103 	qunlock(&fs->lk);
104 }
105 
106 int
107 fsversion(Fsys *fs, int msize, char *version, int nversion)
108 {
109 	void *freep;
110 	Fcall tx, rx;
111 
112 	tx.tag = 0;
113 	tx.type = Tversion;
114 	tx.version = version;
115 	tx.msize = msize;
116 
117 	if(fsrpc(fs, &tx, &rx, &freep) < 0)
118 		return -1;
119 	strecpy(version, version+nversion, rx.version);
120 	free(freep);
121 	return rx.msize;
122 }
123 
124 Fid*
125 fsattach(Fsys *fs, Fid *afid, char *user, char *aname)
126 {
127 	Fcall tx, rx;
128 	Fid *fid;
129 
130 	if(aname == nil)
131 		aname = "";
132 
133 	if((fid = _fsgetfid(fs)) == nil)
134 		return nil;
135 
136 	tx.tag = 0;
137 	tx.type = Tattach;
138 	tx.afid = afid ? afid->fid : NOFID;
139 	tx.fid = fid->fid;
140 	tx.uname = user;
141 	tx.aname = aname;
142 
143 	if(fsrpc(fs, &tx, &rx, 0) < 0){
144 		_fsputfid(fid);
145 		return nil;
146 	}
147 	fid->qid = rx.qid;
148 	return fid;
149 }
150 
151 int
152 fsrpc(Fsys *fs, Fcall *tx, Fcall *rx, void **freep)
153 {
154 	int n, nn;
155 	void *tpkt, *rpkt;
156 
157 	n = sizeS2M(tx);
158 	tpkt = malloc(n);
159 	if(freep)
160 		*freep = nil;
161 	if(tpkt == nil)
162 		return -1;
163 	//fprint(2, "<- %F\n", tx);
164 	nn = convS2M(tx, tpkt, n);
165 	if(nn != n){
166 		free(tpkt);
167 		werrstr("libfs: sizeS2M convS2M mismatch");
168 		fprint(2, "%r\n");
169 		return -1;
170 	}
171 	rpkt = muxrpc(&fs->mux, tpkt);
172 	free(tpkt);
173 	if(rpkt == nil)
174 		return -1;
175 	n = GBIT32((uchar*)rpkt);
176 	nn = convM2S(rpkt, n, rx);
177 	if(nn != n){
178 		free(rpkt);
179 		werrstr("libfs: convM2S packet size mismatch %d %d", n, nn);
180 		fprint(2, "%r\n");
181 		return -1;
182 	}
183 	//fprint(2, "-> %F\n", rx);
184 	if(rx->type == Rerror){
185 		werrstr("%s", rx->ename);
186 		free(rpkt);
187 		return -1;
188 	}
189 	if(rx->type != tx->type+1){
190 		werrstr("packet type mismatch -- tx %d rx %d",
191 			tx->type, rx->type);
192 		free(rpkt);
193 		return -1;
194 	}
195 	if(freep)
196 		*freep = rpkt;
197 	else
198 		free(rpkt);
199 	return 0;
200 }
201 
202 Fid*
203 _fsgetfid(Fsys *fs)
204 {
205 	int i;
206 	Fid *f;
207 
208 	qlock(&fs->lk);
209 	if(fs->freefid == nil){
210 		f = mallocz(sizeof(Fid)*Fidchunk, 1);
211 		if(f == nil){
212 			qunlock(&fs->lk);
213 			return nil;
214 		}
215 		for(i=0; i<Fidchunk; i++){
216 			f[i].fid = fs->nextfid++;
217 			f[i].next = &f[i+1];
218 			f[i].fs = fs;
219 		}
220 		f[i-1].next = nil;
221 		fs->freefid = f;
222 	}
223 	f = fs->freefid;
224 	fs->freefid = f->next;
225 	fs->ref++;
226 	qunlock(&fs->lk);
227 	return f;
228 }
229 
230 void
231 _fsputfid(Fid *f)
232 {
233 	Fsys *fs;
234 
235 	fs = f->fs;
236 	qlock(&fs->lk);
237 	f->next = fs->freefid;
238 	fs->freefid = f;
239 	qunlock(&fs->lk);
240 	_fsdecref(fs);
241 }
242 
243 static int
244 _fsgettag(Mux *mux, void *pkt)
245 {
246 	return GBIT16((uchar*)pkt+5);
247 }
248 
249 static int
250 _fssettag(Mux *mux, void *pkt, uint tag)
251 {
252 	PBIT16((uchar*)pkt+5, tag);
253 	return 0;
254 }
255 
256 static int
257 _fssend(Mux *mux, void *pkt)
258 {
259 	Fsys *fs;
260 
261 	fs = mux->aux;
262 	return threadwrite(fs->fd, pkt, GBIT32((uchar*)pkt));
263 }
264 
265 static void*
266 _fsrecv(Mux *mux)
267 {
268 	uchar *pkt;
269 	uchar buf[4];
270 	int n, nfd;
271 	Fsys *fs;
272 
273 	fs = mux->aux;
274 	n = threadreadn(fs->fd, buf, 4);
275 	if(n != 4)
276 		return nil;
277 	n = GBIT32(buf);
278 	pkt = malloc(n+4);
279 	if(pkt == nil){
280 		fprint(2, "libfs out of memory reading 9p packet; here comes trouble\n");
281 		return nil;
282 	}
283 	PBIT32(pkt, n);
284 	if(threadreadn(fs->fd, pkt+4, n-4) != n-4){
285 		free(pkt);
286 		return nil;
287 	}
288 	if(pkt[4] == Ropenfd){
289 		if((nfd=threadrecvfd(fs->fd)) < 0){
290 			fprint(2, "recv fd error: %r\n");
291 			free(pkt);
292 			return nil;
293 		}
294 		PBIT32(pkt+n-4, nfd);
295 	}
296 	return pkt;
297 }