1 6f4d00ee 2013-09-23 0intro #include "stdinc.h"
  2 6f4d00ee 2013-09-23 0intro 
  3 6f4d00ee 2013-09-23 0intro #include "9.h"
  4 6f4d00ee 2013-09-23 0intro 
  5 6f4d00ee 2013-09-23 0intro static struct {
  6 4b576658 2013-09-23 0intro 	QLock	lock;
  7 6f4d00ee 2013-09-23 0intro 
  8 6f4d00ee 2013-09-23 0intro 	Fid*	free;
  9 6f4d00ee 2013-09-23 0intro 	int	nfree;
 10 6f4d00ee 2013-09-23 0intro 	int	inuse;
 11 6f4d00ee 2013-09-23 0intro } fbox;
 12 6f4d00ee 2013-09-23 0intro 
 13 6f4d00ee 2013-09-23 0intro static void
 14 6f4d00ee 2013-09-23 0intro fidLock(Fid* fid, int flags)
 15 6f4d00ee 2013-09-23 0intro {
 16 6f4d00ee 2013-09-23 0intro 	if(flags & FidFWlock){
 17 4b576658 2013-09-23 0intro 		wlock(&fid->lock);
 18 6f4d00ee 2013-09-23 0intro 		fid->flags = flags;
 19 6f4d00ee 2013-09-23 0intro 	}
 20 6f4d00ee 2013-09-23 0intro 	else
 21 4b576658 2013-09-23 0intro 		rlock(&fid->lock);
 22 6f4d00ee 2013-09-23 0intro 
 23 6f4d00ee 2013-09-23 0intro 	/*
 24 6f4d00ee 2013-09-23 0intro 	 * Callers of file* routines are expected to lock fsys->fs->elk
 25 6f4d00ee 2013-09-23 0intro 	 * before making any calls in order to make sure the epoch doesn't
 26 6f4d00ee 2013-09-23 0intro 	 * change underfoot. With the exception of Tversion and Tattach,
 27 6f4d00ee 2013-09-23 0intro 	 * that implies all 9P functions need to lock on entry and unlock
 28 6f4d00ee 2013-09-23 0intro 	 * on exit. Fortunately, the general case is the 9P functions do
 29 6f4d00ee 2013-09-23 0intro 	 * fidGet on entry and fidPut on exit, so this is a convenient place
 30 6f4d00ee 2013-09-23 0intro 	 * to do the locking.
 31 6f4d00ee 2013-09-23 0intro 	 * No fsys->fs->elk lock is required if the fid is being created
 32 6f4d00ee 2013-09-23 0intro 	 * (Tauth, Tattach and Twalk). FidFCreate is always accompanied by
 33 6f4d00ee 2013-09-23 0intro 	 * FidFWlock so the setting and testing of FidFCreate here and in
 34 6f4d00ee 2013-09-23 0intro 	 * fidUnlock below is always done under fid->lock.
 35 6f4d00ee 2013-09-23 0intro 	 * A side effect is that fidFree is called with the fid locked, and
 36 6f4d00ee 2013-09-23 0intro 	 * must call fidUnlock only after it has disposed of any File
 37 6f4d00ee 2013-09-23 0intro 	 * resources still held.
 38 6f4d00ee 2013-09-23 0intro 	 */
 39 6f4d00ee 2013-09-23 0intro 	if(!(flags & FidFCreate))
 40 6f4d00ee 2013-09-23 0intro 		fsysFsRlock(fid->fsys);
 41 6f4d00ee 2013-09-23 0intro }
 42 6f4d00ee 2013-09-23 0intro 
 43 6f4d00ee 2013-09-23 0intro static void
 44 6f4d00ee 2013-09-23 0intro fidUnlock(Fid* fid)
 45 6f4d00ee 2013-09-23 0intro {
 46 6f4d00ee 2013-09-23 0intro 	if(!(fid->flags & FidFCreate))
 47 6f4d00ee 2013-09-23 0intro 		fsysFsRUnlock(fid->fsys);
 48 6f4d00ee 2013-09-23 0intro 	if(fid->flags & FidFWlock){
 49 6f4d00ee 2013-09-23 0intro 		fid->flags = 0;
 50 4b576658 2013-09-23 0intro 		wunlock(&fid->lock);
 51 6f4d00ee 2013-09-23 0intro 		return;
 52 6f4d00ee 2013-09-23 0intro 	}
 53 4b576658 2013-09-23 0intro 	runlock(&fid->lock);
 54 6f4d00ee 2013-09-23 0intro }
 55 6f4d00ee 2013-09-23 0intro 
 56 6f4d00ee 2013-09-23 0intro static Fid*
 57 6f4d00ee 2013-09-23 0intro fidAlloc(void)
 58 6f4d00ee 2013-09-23 0intro {
 59 6f4d00ee 2013-09-23 0intro 	Fid *fid;
 60 6f4d00ee 2013-09-23 0intro 
 61 4b576658 2013-09-23 0intro 	qlock(&fbox.lock);
 62 6f4d00ee 2013-09-23 0intro 	if(fbox.nfree > 0){
 63 6f4d00ee 2013-09-23 0intro 		fid = fbox.free;
 64 6f4d00ee 2013-09-23 0intro 		fbox.free = fid->hash;
 65 6f4d00ee 2013-09-23 0intro 		fbox.nfree--;
 66 6f4d00ee 2013-09-23 0intro 	}
 67 6f4d00ee 2013-09-23 0intro 	else{
 68 4b576658 2013-09-23 0intro 		fid = vtmallocz(sizeof(Fid));
 69 6f4d00ee 2013-09-23 0intro 	}
 70 6f4d00ee 2013-09-23 0intro 	fbox.inuse++;
 71 4b576658 2013-09-23 0intro 	qunlock(&fbox.lock);
 72 6f4d00ee 2013-09-23 0intro 
 73 6f4d00ee 2013-09-23 0intro 	fid->con = nil;
 74 6f4d00ee 2013-09-23 0intro 	fid->fidno = NOFID;
 75 6f4d00ee 2013-09-23 0intro 	fid->ref = 0;
 76 6f4d00ee 2013-09-23 0intro 	fid->flags = 0;
 77 6f4d00ee 2013-09-23 0intro 	fid->open = FidOCreate;
 78 6f4d00ee 2013-09-23 0intro 	assert(fid->fsys == nil);
 79 6f4d00ee 2013-09-23 0intro 	assert(fid->file == nil);
 80 6f4d00ee 2013-09-23 0intro 	fid->qid = (Qid){0, 0, 0};
 81 6f4d00ee 2013-09-23 0intro 	assert(fid->uid == nil);
 82 6f4d00ee 2013-09-23 0intro 	assert(fid->uname == nil);
 83 6f4d00ee 2013-09-23 0intro 	assert(fid->db == nil);
 84 6f4d00ee 2013-09-23 0intro 	assert(fid->excl == nil);
 85 6f4d00ee 2013-09-23 0intro 	assert(fid->rpc == nil);
 86 6f4d00ee 2013-09-23 0intro 	assert(fid->cuname == nil);
 87 6f4d00ee 2013-09-23 0intro 	fid->hash = fid->next = fid->prev = nil;
 88 6f4d00ee 2013-09-23 0intro 
 89 6f4d00ee 2013-09-23 0intro 	return fid;
 90 6f4d00ee 2013-09-23 0intro }
 91 6f4d00ee 2013-09-23 0intro 
 92 6f4d00ee 2013-09-23 0intro static void
 93 6f4d00ee 2013-09-23 0intro fidFree(Fid* fid)
 94 6f4d00ee 2013-09-23 0intro {
 95 6f4d00ee 2013-09-23 0intro 	if(fid->file != nil){
 96 6f4d00ee 2013-09-23 0intro 		fileDecRef(fid->file);
 97 6f4d00ee 2013-09-23 0intro 		fid->file = nil;
 98 6f4d00ee 2013-09-23 0intro 	}
 99 6f4d00ee 2013-09-23 0intro 	if(fid->db != nil){
100 6f4d00ee 2013-09-23 0intro 		dirBufFree(fid->db);
101 6f4d00ee 2013-09-23 0intro 		fid->db = nil;
102 6f4d00ee 2013-09-23 0intro 	}
103 6f4d00ee 2013-09-23 0intro 	fidUnlock(fid);
104 6f4d00ee 2013-09-23 0intro 
105 6f4d00ee 2013-09-23 0intro 	if(fid->uid != nil){
106 4b576658 2013-09-23 0intro 		vtfree(fid->uid);
107 6f4d00ee 2013-09-23 0intro 		fid->uid = nil;
108 6f4d00ee 2013-09-23 0intro 	}
109 6f4d00ee 2013-09-23 0intro 	if(fid->uname != nil){
110 4b576658 2013-09-23 0intro 		vtfree(fid->uname);
111 6f4d00ee 2013-09-23 0intro 		fid->uname = nil;
112 6f4d00ee 2013-09-23 0intro 	}
113 6f4d00ee 2013-09-23 0intro 	if(fid->excl != nil)
114 6f4d00ee 2013-09-23 0intro 		exclFree(fid);
115 6f4d00ee 2013-09-23 0intro 	if(fid->rpc != nil){
116 6f4d00ee 2013-09-23 0intro 		close(fid->rpc->afd);
117 6f4d00ee 2013-09-23 0intro 		auth_freerpc(fid->rpc);
118 6f4d00ee 2013-09-23 0intro 		fid->rpc = nil;
119 6f4d00ee 2013-09-23 0intro 	}
120 6f4d00ee 2013-09-23 0intro 	if(fid->fsys != nil){
121 6f4d00ee 2013-09-23 0intro 		fsysPut(fid->fsys);
122 6f4d00ee 2013-09-23 0intro 		fid->fsys = nil;
123 6f4d00ee 2013-09-23 0intro 	}
124 6f4d00ee 2013-09-23 0intro 	if(fid->cuname != nil){
125 4b576658 2013-09-23 0intro 		vtfree(fid->cuname);
126 6f4d00ee 2013-09-23 0intro 		fid->cuname = nil;
127 6f4d00ee 2013-09-23 0intro 	}
128 6f4d00ee 2013-09-23 0intro 
129 4b576658 2013-09-23 0intro 	qlock(&fbox.lock);
130 6f4d00ee 2013-09-23 0intro 	fbox.inuse--;
131 6f4d00ee 2013-09-23 0intro 	if(fbox.nfree < 10){
132 6f4d00ee 2013-09-23 0intro 		fid->hash = fbox.free;
133 6f4d00ee 2013-09-23 0intro 		fbox.free = fid;
134 6f4d00ee 2013-09-23 0intro 		fbox.nfree++;
135 6f4d00ee 2013-09-23 0intro 	}
136 6f4d00ee 2013-09-23 0intro 	else{
137 4b576658 2013-09-23 0intro 		vtfree(fid);
138 6f4d00ee 2013-09-23 0intro 	}
139 4b576658 2013-09-23 0intro 	qunlock(&fbox.lock);
140 6f4d00ee 2013-09-23 0intro }
141 6f4d00ee 2013-09-23 0intro 
142 6f4d00ee 2013-09-23 0intro static void
143 6f4d00ee 2013-09-23 0intro fidUnHash(Fid* fid)
144 6f4d00ee 2013-09-23 0intro {
145 6f4d00ee 2013-09-23 0intro 	Fid *fp, **hash;
146 6f4d00ee 2013-09-23 0intro 
147 6f4d00ee 2013-09-23 0intro 	assert(fid->ref == 0);
148 6f4d00ee 2013-09-23 0intro 
149 6f4d00ee 2013-09-23 0intro 	hash = &fid->con->fidhash[fid->fidno % NFidHash];
150 6f4d00ee 2013-09-23 0intro 	for(fp = *hash; fp != nil; fp = fp->hash){
151 6f4d00ee 2013-09-23 0intro 		if(fp == fid){
152 6f4d00ee 2013-09-23 0intro 			*hash = fp->hash;
153 6f4d00ee 2013-09-23 0intro 			break;
154 6f4d00ee 2013-09-23 0intro 		}
155 6f4d00ee 2013-09-23 0intro 		hash = &fp->hash;
156 6f4d00ee 2013-09-23 0intro 	}
157 6f4d00ee 2013-09-23 0intro 	assert(fp == fid);
158 6f4d00ee 2013-09-23 0intro 
159 6f4d00ee 2013-09-23 0intro 	if(fid->prev != nil)
160 6f4d00ee 2013-09-23 0intro 		fid->prev->next = fid->next;
161 6f4d00ee 2013-09-23 0intro 	else
162 6f4d00ee 2013-09-23 0intro 		fid->con->fhead = fid->next;
163 6f4d00ee 2013-09-23 0intro 	if(fid->next != nil)
164 6f4d00ee 2013-09-23 0intro 		fid->next->prev = fid->prev;
165 6f4d00ee 2013-09-23 0intro 	else
166 6f4d00ee 2013-09-23 0intro 		fid->con->ftail = fid->prev;
167 6f4d00ee 2013-09-23 0intro 	fid->prev = fid->next = nil;
168 6f4d00ee 2013-09-23 0intro 
169 6f4d00ee 2013-09-23 0intro 	fid->con->nfid--;
170 6f4d00ee 2013-09-23 0intro }
171 6f4d00ee 2013-09-23 0intro 
172 6f4d00ee 2013-09-23 0intro Fid*
173 6f4d00ee 2013-09-23 0intro fidGet(Con* con, u32int fidno, int flags)
174 6f4d00ee 2013-09-23 0intro {
175 6f4d00ee 2013-09-23 0intro 	Fid *fid, **hash;
176 6f4d00ee 2013-09-23 0intro 
177 6f4d00ee 2013-09-23 0intro 	if(fidno == NOFID)
178 6f4d00ee 2013-09-23 0intro 		return nil;
179 6f4d00ee 2013-09-23 0intro 
180 6f4d00ee 2013-09-23 0intro 	hash = &con->fidhash[fidno % NFidHash];
181 4b576658 2013-09-23 0intro 	qlock(&con->fidlock);
182 6f4d00ee 2013-09-23 0intro 	for(fid = *hash; fid != nil; fid = fid->hash){
183 6f4d00ee 2013-09-23 0intro 		if(fid->fidno != fidno)
184 6f4d00ee 2013-09-23 0intro 			continue;
185 6f4d00ee 2013-09-23 0intro 
186 6f4d00ee 2013-09-23 0intro 		/*
187 6f4d00ee 2013-09-23 0intro 		 * Already in use is an error
188 6f4d00ee 2013-09-23 0intro 		 * when called from attach, clone or walk.
189 6f4d00ee 2013-09-23 0intro 		 */
190 6f4d00ee 2013-09-23 0intro 		if(flags & FidFCreate){
191 4b576658 2013-09-23 0intro 			qunlock(&con->fidlock);
192 4b576658 2013-09-23 0intro 			werrstr("%s: fid 0x%ud in use", argv0, fidno);
193 6f4d00ee 2013-09-23 0intro 			return nil;
194 6f4d00ee 2013-09-23 0intro 		}
195 6f4d00ee 2013-09-23 0intro 		fid->ref++;
196 4b576658 2013-09-23 0intro 		qunlock(&con->fidlock);
197 6f4d00ee 2013-09-23 0intro 
198 6f4d00ee 2013-09-23 0intro 		fidLock(fid, flags);
199 6f4d00ee 2013-09-23 0intro 		if((fid->open & FidOCreate) || fid->fidno == NOFID){
200 6f4d00ee 2013-09-23 0intro 			fidPut(fid);
201 4b576658 2013-09-23 0intro 			werrstr("%s: fid invalid", argv0);
202 6f4d00ee 2013-09-23 0intro 			return nil;
203 6f4d00ee 2013-09-23 0intro 		}
204 6f4d00ee 2013-09-23 0intro 		return fid;
205 6f4d00ee 2013-09-23 0intro 	}
206 6f4d00ee 2013-09-23 0intro 
207 6f4d00ee 2013-09-23 0intro 	if((flags & FidFCreate) && (fid = fidAlloc()) != nil){
208 6f4d00ee 2013-09-23 0intro 		assert(flags & FidFWlock);
209 6f4d00ee 2013-09-23 0intro 		fid->con = con;
210 6f4d00ee 2013-09-23 0intro 		fid->fidno = fidno;
211 6f4d00ee 2013-09-23 0intro 		fid->ref = 1;
212 6f4d00ee 2013-09-23 0intro 
213 6f4d00ee 2013-09-23 0intro 		fid->hash = *hash;
214 6f4d00ee 2013-09-23 0intro 		*hash = fid;
215 6f4d00ee 2013-09-23 0intro 		if(con->ftail != nil){
216 6f4d00ee 2013-09-23 0intro 			fid->prev = con->ftail;
217 6f4d00ee 2013-09-23 0intro 			con->ftail->next = fid;
218 6f4d00ee 2013-09-23 0intro 		}
219 6f4d00ee 2013-09-23 0intro 		else{
220 6f4d00ee 2013-09-23 0intro 			con->fhead = fid;
221 6f4d00ee 2013-09-23 0intro 			fid->prev = nil;
222 6f4d00ee 2013-09-23 0intro 		}
223 6f4d00ee 2013-09-23 0intro 		con->ftail = fid;
224 6f4d00ee 2013-09-23 0intro 		fid->next = nil;
225 6f4d00ee 2013-09-23 0intro 
226 6f4d00ee 2013-09-23 0intro 		con->nfid++;
227 4b576658 2013-09-23 0intro 		qunlock(&con->fidlock);
228 6f4d00ee 2013-09-23 0intro 
229 6f4d00ee 2013-09-23 0intro 		/*
230 6f4d00ee 2013-09-23 0intro 		 * The FidOCreate flag is used to prevent any
231 6f4d00ee 2013-09-23 0intro 		 * accidental access to the Fid between unlocking the
232 6f4d00ee 2013-09-23 0intro 		 * hash and acquiring the Fid lock for return.
233 6f4d00ee 2013-09-23 0intro 		 */
234 6f4d00ee 2013-09-23 0intro 		fidLock(fid, flags);
235 6f4d00ee 2013-09-23 0intro 		fid->open &= ~FidOCreate;
236 6f4d00ee 2013-09-23 0intro 		return fid;
237 6f4d00ee 2013-09-23 0intro 	}
238 4b576658 2013-09-23 0intro 	qunlock(&con->fidlock);
239 6f4d00ee 2013-09-23 0intro 
240 4b576658 2013-09-23 0intro 	werrstr("%s: fid not found", argv0);
241 6f4d00ee 2013-09-23 0intro 	return nil;
242 6f4d00ee 2013-09-23 0intro }
243 6f4d00ee 2013-09-23 0intro 
244 6f4d00ee 2013-09-23 0intro void
245 6f4d00ee 2013-09-23 0intro fidPut(Fid* fid)
246 6f4d00ee 2013-09-23 0intro {
247 4b576658 2013-09-23 0intro 	qlock(&fid->con->fidlock);
248 6f4d00ee 2013-09-23 0intro 	assert(fid->ref > 0);
249 6f4d00ee 2013-09-23 0intro 	fid->ref--;
250 4b576658 2013-09-23 0intro 	qunlock(&fid->con->fidlock);
251 6f4d00ee 2013-09-23 0intro 
252 6f4d00ee 2013-09-23 0intro 	if(fid->ref == 0 && fid->fidno == NOFID){
253 6f4d00ee 2013-09-23 0intro 		fidFree(fid);
254 6f4d00ee 2013-09-23 0intro 		return;
255 6f4d00ee 2013-09-23 0intro 	}
256 6f4d00ee 2013-09-23 0intro 	fidUnlock(fid);
257 6f4d00ee 2013-09-23 0intro }
258 6f4d00ee 2013-09-23 0intro 
259 6f4d00ee 2013-09-23 0intro void
260 6f4d00ee 2013-09-23 0intro fidClunk(Fid* fid)
261 6f4d00ee 2013-09-23 0intro {
262 6f4d00ee 2013-09-23 0intro 	assert(fid->flags & FidFWlock);
263 6f4d00ee 2013-09-23 0intro 
264 4b576658 2013-09-23 0intro 	qlock(&fid->con->fidlock);
265 6f4d00ee 2013-09-23 0intro 	assert(fid->ref > 0);
266 6f4d00ee 2013-09-23 0intro 	fid->ref--;
267 6f4d00ee 2013-09-23 0intro 	fidUnHash(fid);
268 6f4d00ee 2013-09-23 0intro 	fid->fidno = NOFID;
269 4b576658 2013-09-23 0intro 	qunlock(&fid->con->fidlock);
270 6f4d00ee 2013-09-23 0intro 
271 6f4d00ee 2013-09-23 0intro 	if(fid->ref > 0){
272 6f4d00ee 2013-09-23 0intro 		/* not reached - fidUnHash requires ref == 0 */
273 6f4d00ee 2013-09-23 0intro 		fidUnlock(fid);
274 6f4d00ee 2013-09-23 0intro 		return;
275 6f4d00ee 2013-09-23 0intro 	}
276 6f4d00ee 2013-09-23 0intro 	fidFree(fid);
277 6f4d00ee 2013-09-23 0intro }
278 6f4d00ee 2013-09-23 0intro 
279 6f4d00ee 2013-09-23 0intro void
280 6f4d00ee 2013-09-23 0intro fidClunkAll(Con* con)
281 6f4d00ee 2013-09-23 0intro {
282 6f4d00ee 2013-09-23 0intro 	Fid *fid;
283 6f4d00ee 2013-09-23 0intro 	u32int fidno;
284 6f4d00ee 2013-09-23 0intro 
285 4b576658 2013-09-23 0intro 	qlock(&con->fidlock);
286 6f4d00ee 2013-09-23 0intro 	while(con->fhead != nil){
287 6f4d00ee 2013-09-23 0intro 		fidno = con->fhead->fidno;
288 4b576658 2013-09-23 0intro 		qunlock(&con->fidlock);
289 6f4d00ee 2013-09-23 0intro 		if((fid = fidGet(con, fidno, FidFWlock)) != nil)
290 6f4d00ee 2013-09-23 0intro 			fidClunk(fid);
291 4b576658 2013-09-23 0intro 		qlock(&con->fidlock);
292 6f4d00ee 2013-09-23 0intro 	}
293 4b576658 2013-09-23 0intro 	qunlock(&con->fidlock);
294 6f4d00ee 2013-09-23 0intro }
295 6f4d00ee 2013-09-23 0intro 
296 6f4d00ee 2013-09-23 0intro void
297 6f4d00ee 2013-09-23 0intro fidInit(void)
298 6f4d00ee 2013-09-23 0intro {
299 6f4d00ee 2013-09-23 0intro }