1 /* $NetBSD: ptyfs_subr.c,v 1.2 2004/11/11 19:19:59 jdolecek Exp $ */
2
3 /*
4 * Copyright (c) 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Jan-Simon Pendry.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 * @(#)ptyfs_subr.c 8.6 (Berkeley) 5/14/95
35 */
36
37 /*
38 * Copyright (c) 1994 Christopher G. Demetriou. All rights reserved.
39 * Copyright (c) 1993 Jan-Simon Pendry
40 *
41 * This code is derived from software contributed to Berkeley by
42 * Jan-Simon Pendry.
43 *
44 * Redistribution and use in source and binary forms, with or without
45 * modification, are permitted provided that the following conditions
46 * are met:
47 * 1. Redistributions of source code must retain the above copyright
48 * notice, this list of conditions and the following disclaimer.
49 * 2. Redistributions in binary form must reproduce the above copyright
50 * notice, this list of conditions and the following disclaimer in the
51 * documentation and/or other materials provided with the distribution.
52 * 3. All advertising materials mentioning features or use of this software
53 * must display the following acknowledgement:
54 * This product includes software developed by the University of
55 * California, Berkeley and its contributors.
56 * 4. Neither the name of the University nor the names of its contributors
57 * may be used to endorse or promote products derived from this software
58 * without specific prior written permission.
59 *
60 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
61 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
62 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
63 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
64 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
65 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
66 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
67 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
68 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
69 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
70 * SUCH DAMAGE.
71 *
72 * @(#)procfs_subr.c 8.6 (Berkeley) 5/14/95
73 */
74
75 #include <sys/cdefs.h>
76 __KERNEL_RCSID(0, "$NetBSD: ptyfs_subr.c,v 1.2 2004/11/11 19:19:59 jdolecek Exp $");
77
78 #include <sys/param.h>
79 #include <sys/systm.h>
80 #include <sys/time.h>
81 #include <sys/kernel.h>
82 #include <sys/vnode.h>
83 #include <sys/malloc.h>
84 #include <sys/stat.h>
85 #include <sys/file.h>
86 #include <sys/namei.h>
87 #include <sys/filedesc.h>
88 #include <sys/select.h>
89 #include <sys/tty.h>
90 #include <sys/pty.h>
91
92 #include <fs/ptyfs/ptyfs.h>
93 #include <miscfs/specfs/specdev.h>
94
95 static struct lock ptyfs_hashlock;
96
97 static LIST_HEAD(ptyfs_hashhead, ptyfsnode) *ptyfs_used_tbl, *ptyfs_free_tbl;
98 static u_long ptyfs_used_mask, ptyfs_free_mask; /* size of hash table - 1 */
99 static struct simplelock ptyfs_used_slock, ptyfs_free_slock;
100
101 static void ptyfs_getinfo(struct ptyfsnode *, struct proc *);
102
103 static void ptyfs_hashins(struct ptyfsnode *);
104 static void ptyfs_hashrem(struct ptyfsnode *);
105
106 static struct vnode *ptyfs_used_get(ptyfstype, int, struct mount *);
107 static struct ptyfsnode *ptyfs_free_get(ptyfstype, int, struct proc *);
108
109 static void ptyfs_rehash(struct simplelock *, struct ptyfs_hashhead **,
110 u_long *);
111
112 #define PTYHASH(type, pty, mask) (PTYFS_FILENO(type, pty) % (mask + 1))
113
114
115 static void
116 ptyfs_getinfo(struct ptyfsnode *ptyfs, struct proc *p)
117 {
118 extern struct ptm_pty *ptyfs_save_ptm, ptm_ptyfspty;
119
120 if (ptyfs->ptyfs_type == PTYFSroot) {
121 ptyfs->ptyfs_mode = S_IRUSR|S_IXUSR|S_IRGRP|S_IXGRP|
122 S_IROTH|S_IXOTH;
123 goto out;
124 } else
125 ptyfs->ptyfs_mode = S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|
126 S_IROTH|S_IWOTH;
127
128 if (ptyfs_save_ptm != NULL && ptyfs_save_ptm != &ptm_ptyfspty) {
129 int error;
130 struct nameidata nd;
131 char ttyname[64];
132 struct ucred *cred;
133 struct vattr va;
134 /*
135 * We support traditional ptys, so we copy the info
136 * from the inode
137 */
138 if ((error = (*ptyfs_save_ptm->makename)(
139 ptyfs_save_ptm, ttyname, sizeof(ttyname),
140 ptyfs->ptyfs_pty, ptyfs->ptyfs_type == PTYFSpts ? 't'
141 : 'p')) != 0)
142 goto out;
143 NDINIT(&nd, LOOKUP, NOFOLLOW|LOCKLEAF, UIO_SYSSPACE, ttyname,
144 p);
145 if ((error = namei(&nd)) != 0)
146 goto out;
147 cred = crget();
148 error = VOP_GETATTR(nd.ni_vp, &va, cred, p);
149 crfree(cred);
150 VOP_UNLOCK(nd.ni_vp, 0);
151 vrele(nd.ni_vp);
152 if (error)
153 goto out;
154 ptyfs->ptyfs_uid = va.va_uid;
155 ptyfs->ptyfs_gid = va.va_gid;
156 ptyfs->ptyfs_mode = va.va_mode;
157 ptyfs->ptyfs_flags = va.va_flags;
158 ptyfs->ptyfs_birthtime = va.va_birthtime;
159 ptyfs->ptyfs_ctime = va.va_ctime;
160 ptyfs->ptyfs_mtime = va.va_mtime;
161 ptyfs->ptyfs_atime = va.va_atime;
162 return;
163 }
164 out:
165 ptyfs->ptyfs_uid = ptyfs->ptyfs_gid = 0;
166 TIMEVAL_TO_TIMESPEC(&time, &ptyfs->ptyfs_ctime);
167 ptyfs->ptyfs_birthtime = ptyfs->ptyfs_mtime =
168 ptyfs->ptyfs_atime = ptyfs->ptyfs_ctime;
169 ptyfs->ptyfs_flags = 0;
170 }
171
172
173 /*
174 * allocate a ptyfsnode/vnode pair. the vnode is
175 * referenced, and locked.
176 *
177 * the pid, ptyfs_type, and mount point uniquely
178 * identify a ptyfsnode. the mount point is needed
179 * because someone might mount this filesystem
180 * twice.
181 *
182 * all ptyfsnodes are maintained on a singly-linked
183 * list. new nodes are only allocated when they cannot
184 * be found on this list. entries on the list are
185 * removed when the vfs reclaim entry is called.
186 *
187 * a single lock is kept for the entire list. this is
188 * needed because the getnewvnode() function can block
189 * waiting for a vnode to become free, in which case there
190 * may be more than one ptyess trying to get the same
191 * vnode. this lock is only taken if we are going to
192 * call getnewvnode, since the kernel itself is single-threaded.
193 *
194 * if an entry is found on the list, then call vget() to
195 * take a reference. this is done because there may be
196 * zero references to it and so it needs to removed from
197 * the vnode free list.
198 */
199 int
200 ptyfs_allocvp(struct mount *mp, struct vnode **vpp, ptyfstype type, int pty,
201 struct proc *p)
202 {
203 struct ptyfsnode *ptyfs;
204 struct vnode *vp, *nvp;
205 int error;
206
207 do {
208 if ((*vpp = ptyfs_used_get(type, pty, mp)) != NULL)
209 return 0;
210 } while (lockmgr(&ptyfs_hashlock, LK_EXCLUSIVE|LK_SLEEPFAIL, 0));
211
212 if ((error = getnewvnode(VT_PTYFS, mp, ptyfs_vnodeop_p, &vp)) != 0) {
213 *vpp = NULL;
214 lockmgr(&ptyfs_hashlock, LK_RELEASE, NULL);
215 return error;
216 }
217
218 vp->v_data = ptyfs = ptyfs_free_get(type, pty, p);
219 ptyfs->ptyfs_vnode = vp;
220
221 switch (type) {
222 case PTYFSroot: /* /pts = dr-xr-xr-x */
223 vp->v_type = VDIR;
224 vp->v_flag = VROOT;
225 break;
226
227 case PTYFSpts: /* /pts/N = cxxxxxxxxx */
228 case PTYFSptc: /* controlling side = cxxxxxxxxx */
229 vp->v_type = VCHR;
230 if ((nvp = checkalias(vp, PTYFS_MAKEDEV(ptyfs), mp)) != NULL) {
231 /*
232 * Discard unneeded vnode, but save its inode.
233 */
234 nvp->v_data = vp->v_data;
235 vp->v_data = NULL;
236 /* XXX spec_vnodeops has no locking, do it explicitly */
237 VOP_UNLOCK(vp, 0);
238 vp->v_op = spec_vnodeop_p;
239 vp->v_flag &= ~VLOCKSWORK;
240 vrele(vp);
241 vgone(vp);
242 lockmgr(&nvp->v_lock, LK_EXCLUSIVE, &nvp->v_interlock);
243 /*
244 * Reinitialize aliased inode.
245 */
246 vp = nvp;
247 ptyfs->ptyfs_vnode = vp;
248 }
249 break;
250 default:
251 panic("ptyfs_allocvp");
252 }
253
254 ptyfs_hashins(ptyfs);
255 uvm_vnp_setsize(vp, 0);
256 lockmgr(&ptyfs_hashlock, LK_RELEASE, NULL);
257
258 *vpp = vp;
259 return 0;
260 }
261
262 int
263 ptyfs_freevp(struct vnode *vp)
264 {
265 struct ptyfsnode *ptyfs = VTOPTYFS(vp);
266
267 ptyfs_hashrem(ptyfs);
268 vp->v_data = NULL;
269 return 0;
270 }
271
272 /*
273 * Initialize ptyfsnode hash table.
274 */
275 void
276 ptyfs_hashinit(void)
277 {
278 lockinit(&ptyfs_hashlock, PINOD, "ptyfs_hashlock", 0, 0);
279 ptyfs_used_tbl = hashinit(desiredvnodes / 4, HASH_LIST, M_UFSMNT,
280 M_WAITOK, &ptyfs_used_mask);
281 ptyfs_free_tbl = hashinit(desiredvnodes / 4, HASH_LIST, M_UFSMNT,
282 M_WAITOK, &ptyfs_free_mask);
283 simple_lock_init(&ptyfs_used_slock);
284 simple_lock_init(&ptyfs_free_slock);
285 }
286
287 void
288 ptyfs_hashreinit(void)
289 {
290 ptyfs_rehash(&ptyfs_used_slock, &ptyfs_used_tbl, &ptyfs_used_mask);
291 ptyfs_rehash(&ptyfs_free_slock, &ptyfs_free_tbl, &ptyfs_free_mask);
292 }
293
294 static void
295 ptyfs_rehash(struct simplelock *hlock, struct ptyfs_hashhead **hhead,
296 u_long *hmask)
297 {
298 struct ptyfsnode *pp;
299 struct ptyfs_hashhead *oldhash, *hash;
300 u_long i, oldmask, mask, val;
301
302 hash = hashinit(desiredvnodes / 4, HASH_LIST, M_UFSMNT, M_WAITOK,
303 &mask);
304
305 simple_lock(hlock);
306 oldhash = *hhead;
307 oldmask = *hmask;
308 *hhead = hash;
309 *hmask = mask;
310 for (i = 0; i <= oldmask; i++) {
311 while ((pp = LIST_FIRST(&oldhash[i])) != NULL) {
312 LIST_REMOVE(pp, ptyfs_hash);
313 val = PTYHASH(pp->ptyfs_type, pp->ptyfs_pty,
314 ptyfs_used_mask);
315 LIST_INSERT_HEAD(&hash[val], pp, ptyfs_hash);
316 }
317 }
318 simple_unlock(hlock);
319 hashdone(oldhash, M_UFSMNT);
320 }
321
322 /*
323 * Free ptyfsnode hash table.
324 */
325 void
326 ptyfs_hashdone(void)
327 {
328 hashdone(ptyfs_used_tbl, M_UFSMNT);
329 hashdone(ptyfs_free_tbl, M_UFSMNT);
330 }
331
332 /*
333 * Get a ptyfsnode from the free table, or allocate one.
334 * Removes the node from the free table.
335 */
336 struct ptyfsnode *
337 ptyfs_free_get(ptyfstype type, int pty, struct proc *p)
338 {
339 struct ptyfs_hashhead *ppp;
340 struct ptyfsnode *pp;
341
342 simple_lock(&ptyfs_free_slock);
343 ppp = &ptyfs_free_tbl[PTYHASH(type, pty, ptyfs_free_mask)];
344 LIST_FOREACH(pp, ppp, ptyfs_hash) {
345 if (pty == pp->ptyfs_pty && pp->ptyfs_type == type) {
346 LIST_REMOVE(pp, ptyfs_hash);
347 simple_unlock(&ptyfs_free_slock);
348 return pp;
349 }
350 }
351 simple_unlock(&ptyfs_free_slock);
352
353 MALLOC(pp, void *, sizeof(struct ptyfsnode), M_TEMP, M_WAITOK);
354 pp->ptyfs_pty = pty;
355 pp->ptyfs_type = type;
356 pp->ptyfs_fileno = PTYFS_FILENO(pty, type);
357 ptyfs_getinfo(pp, p);
358 return pp;
359 }
360
361 struct vnode *
362 ptyfs_used_get(ptyfstype type, int pty, struct mount *mp)
363 {
364 struct ptyfs_hashhead *ppp;
365 struct ptyfsnode *pp;
366 struct vnode *vp;
367
368 loop:
369 simple_lock(&ptyfs_used_slock);
370 ppp = &ptyfs_used_tbl[PTYHASH(type, pty, ptyfs_used_mask)];
371 LIST_FOREACH(pp, ppp, ptyfs_hash) {
372 vp = PTYFSTOV(pp);
373 if (pty == pp->ptyfs_pty && pp->ptyfs_type == type &&
374 vp->v_mount == mp) {
375 simple_lock(&vp->v_interlock);
376 simple_unlock(&ptyfs_used_slock);
377 if (vget(vp, LK_EXCLUSIVE | LK_INTERLOCK))
378 goto loop;
379 return vp;
380 }
381 }
382 simple_unlock(&ptyfs_used_slock);
383 return NULL;
384 }
385
386 /*
387 * Insert the ptyfsnode into the used table and lock it.
388 */
389 static void
390 ptyfs_hashins(struct ptyfsnode *pp)
391 {
392 struct ptyfs_hashhead *ppp;
393
394 /* lock the ptyfsnode, then put it on the appropriate hash list */
395 lockmgr(&pp->ptyfs_vnode->v_lock, LK_EXCLUSIVE, NULL);
396
397 simple_lock(&ptyfs_used_slock);
398 ppp = &ptyfs_used_tbl[PTYHASH(pp->ptyfs_type, pp->ptyfs_pty,
399 ptyfs_used_mask)];
400 LIST_INSERT_HEAD(ppp, pp, ptyfs_hash);
401 simple_unlock(&ptyfs_used_slock);
402 }
403
404 /*
405 * Remove the ptyfsnode from the used table, and add it to the free table
406 */
407 static void
408 ptyfs_hashrem(struct ptyfsnode *pp)
409 {
410 struct ptyfs_hashhead *ppp;
411
412 simple_lock(&ptyfs_used_slock);
413 LIST_REMOVE(pp, ptyfs_hash);
414 simple_unlock(&ptyfs_used_slock);
415
416 simple_lock(&ptyfs_free_slock);
417 ppp = &ptyfs_free_tbl[PTYHASH(pp->ptyfs_type, pp->ptyfs_pty,
418 ptyfs_free_mask)];
419 LIST_INSERT_HEAD(ppp, pp, ptyfs_hash);
420 simple_unlock(&ptyfs_free_slock);
421 }
Cache object: bd910f7822f612f3c0e31fcf27fe2dd2
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