1 /* $NetBSD: ptyfs_subr.c,v 1.7 2006/05/14 21:31:52 elad 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 1.7 2006/05/14 21:31:52 elad 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 #include <sys/kauth.h>
92
93 #include <fs/ptyfs/ptyfs.h>
94 #include <miscfs/specfs/specdev.h>
95
96 static struct lock ptyfs_hashlock;
97
98 static LIST_HEAD(ptyfs_hashhead, ptyfsnode) *ptyfs_used_tbl, *ptyfs_free_tbl;
99 static u_long ptyfs_used_mask, ptyfs_free_mask; /* size of hash table - 1 */
100 static struct simplelock ptyfs_used_slock, ptyfs_free_slock;
101
102 static void ptyfs_getinfo(struct ptyfsnode *, struct lwp *);
103
104 static void ptyfs_hashins(struct ptyfsnode *);
105 static void ptyfs_hashrem(struct ptyfsnode *);
106
107 static struct vnode *ptyfs_used_get(ptyfstype, int, struct mount *);
108 static struct ptyfsnode *ptyfs_free_get(ptyfstype, int, struct lwp *);
109
110 static void ptyfs_rehash(struct simplelock *, struct ptyfs_hashhead **,
111 u_long *);
112
113 #define PTYHASH(type, pty, mask) (PTYFS_FILENO(type, pty) % (mask + 1))
114
115
116 static void
117 ptyfs_getinfo(struct ptyfsnode *ptyfs, struct lwp *l)
118 {
119 extern struct ptm_pty *ptyfs_save_ptm, ptm_ptyfspty;
120
121 if (ptyfs->ptyfs_type == PTYFSroot) {
122 ptyfs->ptyfs_mode = S_IRUSR|S_IXUSR|S_IRGRP|S_IXGRP|
123 S_IROTH|S_IXOTH;
124 goto out;
125 } else
126 ptyfs->ptyfs_mode = S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|
127 S_IROTH|S_IWOTH;
128
129 if (ptyfs_save_ptm != NULL && ptyfs_save_ptm != &ptm_ptyfspty) {
130 int error;
131 struct nameidata nd;
132 char ttyname[64];
133 kauth_cred_t cred;
134 struct vattr va;
135 /*
136 * We support traditional ptys, so we copy the info
137 * from the inode
138 */
139 if ((error = (*ptyfs_save_ptm->makename)(
140 ptyfs_save_ptm, l, ttyname, sizeof(ttyname),
141 ptyfs->ptyfs_pty, ptyfs->ptyfs_type == PTYFSpts ? 't'
142 : 'p')) != 0)
143 goto out;
144 NDINIT(&nd, LOOKUP, NOFOLLOW|LOCKLEAF, UIO_SYSSPACE, ttyname,
145 l);
146 if ((error = namei(&nd)) != 0)
147 goto out;
148 cred = kauth_cred_alloc();
149 error = VOP_GETATTR(nd.ni_vp, &va, cred, l);
150 kauth_cred_free(cred);
151 VOP_UNLOCK(nd.ni_vp, 0);
152 vrele(nd.ni_vp);
153 if (error)
154 goto out;
155 ptyfs->ptyfs_uid = va.va_uid;
156 ptyfs->ptyfs_gid = va.va_gid;
157 ptyfs->ptyfs_mode = va.va_mode;
158 ptyfs->ptyfs_flags = va.va_flags;
159 ptyfs->ptyfs_birthtime = va.va_birthtime;
160 ptyfs->ptyfs_ctime = va.va_ctime;
161 ptyfs->ptyfs_mtime = va.va_mtime;
162 ptyfs->ptyfs_atime = va.va_atime;
163 return;
164 }
165 out:
166 ptyfs->ptyfs_uid = ptyfs->ptyfs_gid = 0;
167 ptyfs->ptyfs_flags |= PTYFS_CHANGE;
168 PTYFS_ITIMES(ptyfs, NULL, NULL, NULL);
169 ptyfs->ptyfs_birthtime = ptyfs->ptyfs_mtime =
170 ptyfs->ptyfs_atime = ptyfs->ptyfs_ctime;
171 ptyfs->ptyfs_flags = 0;
172 }
173
174
175 /*
176 * allocate a ptyfsnode/vnode pair. the vnode is
177 * referenced, and locked.
178 *
179 * the pid, ptyfs_type, and mount point uniquely
180 * identify a ptyfsnode. the mount point is needed
181 * because someone might mount this filesystem
182 * twice.
183 *
184 * all ptyfsnodes are maintained on a singly-linked
185 * list. new nodes are only allocated when they cannot
186 * be found on this list. entries on the list are
187 * removed when the vfs reclaim entry is called.
188 *
189 * a single lock is kept for the entire list. this is
190 * needed because the getnewvnode() function can block
191 * waiting for a vnode to become free, in which case there
192 * may be more than one ptyess trying to get the same
193 * vnode. this lock is only taken if we are going to
194 * call getnewvnode, since the kernel itself is single-threaded.
195 *
196 * if an entry is found on the list, then call vget() to
197 * take a reference. this is done because there may be
198 * zero references to it and so it needs to removed from
199 * the vnode free list.
200 */
201 int
202 ptyfs_allocvp(struct mount *mp, struct vnode **vpp, ptyfstype type, int pty,
203 struct lwp *l)
204 {
205 struct ptyfsnode *ptyfs;
206 struct vnode *vp, *nvp;
207 int error;
208
209 do {
210 if ((*vpp = ptyfs_used_get(type, pty, mp)) != NULL)
211 return 0;
212 } while (lockmgr(&ptyfs_hashlock, LK_EXCLUSIVE|LK_SLEEPFAIL, 0));
213
214 if ((error = getnewvnode(VT_PTYFS, mp, ptyfs_vnodeop_p, &vp)) != 0) {
215 *vpp = NULL;
216 lockmgr(&ptyfs_hashlock, LK_RELEASE, NULL);
217 return error;
218 }
219
220 vp->v_data = ptyfs = ptyfs_free_get(type, pty, l);
221 ptyfs->ptyfs_vnode = vp;
222
223 switch (type) {
224 case PTYFSroot: /* /pts = dr-xr-xr-x */
225 vp->v_type = VDIR;
226 vp->v_flag = VROOT;
227 break;
228
229 case PTYFSpts: /* /pts/N = cxxxxxxxxx */
230 case PTYFSptc: /* controlling side = cxxxxxxxxx */
231 vp->v_type = VCHR;
232 if ((nvp = checkalias(vp, PTYFS_MAKEDEV(ptyfs), mp)) != NULL) {
233 /*
234 * Discard unneeded vnode, but save its inode.
235 */
236 nvp->v_data = vp->v_data;
237 vp->v_data = NULL;
238 /* XXX spec_vnodeops has no locking, do it explicitly */
239 VOP_UNLOCK(vp, 0);
240 vp->v_op = spec_vnodeop_p;
241 vp->v_flag &= ~VLOCKSWORK;
242 vrele(vp);
243 vgone(vp);
244 lockmgr(&nvp->v_lock, LK_EXCLUSIVE, &nvp->v_interlock);
245 /*
246 * Reinitialize aliased inode.
247 */
248 vp = nvp;
249 ptyfs->ptyfs_vnode = vp;
250 }
251 break;
252 default:
253 panic("ptyfs_allocvp");
254 }
255
256 ptyfs_hashins(ptyfs);
257 uvm_vnp_setsize(vp, 0);
258 lockmgr(&ptyfs_hashlock, LK_RELEASE, NULL);
259
260 *vpp = vp;
261 return 0;
262 }
263
264 int
265 ptyfs_freevp(struct vnode *vp)
266 {
267 struct ptyfsnode *ptyfs = VTOPTYFS(vp);
268
269 ptyfs_hashrem(ptyfs);
270 vp->v_data = NULL;
271 return 0;
272 }
273
274 /*
275 * Initialize ptyfsnode hash table.
276 */
277 void
278 ptyfs_hashinit(void)
279 {
280 lockinit(&ptyfs_hashlock, PINOD, "ptyfs_hashlock", 0, 0);
281 ptyfs_used_tbl = hashinit(desiredvnodes / 4, HASH_LIST, M_UFSMNT,
282 M_WAITOK, &ptyfs_used_mask);
283 ptyfs_free_tbl = hashinit(desiredvnodes / 4, HASH_LIST, M_UFSMNT,
284 M_WAITOK, &ptyfs_free_mask);
285 simple_lock_init(&ptyfs_used_slock);
286 simple_lock_init(&ptyfs_free_slock);
287 }
288
289 void
290 ptyfs_hashreinit(void)
291 {
292 ptyfs_rehash(&ptyfs_used_slock, &ptyfs_used_tbl, &ptyfs_used_mask);
293 ptyfs_rehash(&ptyfs_free_slock, &ptyfs_free_tbl, &ptyfs_free_mask);
294 }
295
296 static void
297 ptyfs_rehash(struct simplelock *hlock, struct ptyfs_hashhead **hhead,
298 u_long *hmask)
299 {
300 struct ptyfsnode *pp;
301 struct ptyfs_hashhead *oldhash, *hash;
302 u_long i, oldmask, mask, val;
303
304 hash = hashinit(desiredvnodes / 4, HASH_LIST, M_UFSMNT, M_WAITOK,
305 &mask);
306
307 simple_lock(hlock);
308 oldhash = *hhead;
309 oldmask = *hmask;
310 *hhead = hash;
311 *hmask = mask;
312 for (i = 0; i <= oldmask; i++) {
313 while ((pp = LIST_FIRST(&oldhash[i])) != NULL) {
314 LIST_REMOVE(pp, ptyfs_hash);
315 val = PTYHASH(pp->ptyfs_type, pp->ptyfs_pty,
316 ptyfs_used_mask);
317 LIST_INSERT_HEAD(&hash[val], pp, ptyfs_hash);
318 }
319 }
320 simple_unlock(hlock);
321 hashdone(oldhash, M_UFSMNT);
322 }
323
324 /*
325 * Free ptyfsnode hash table.
326 */
327 void
328 ptyfs_hashdone(void)
329 {
330 hashdone(ptyfs_used_tbl, M_UFSMNT);
331 hashdone(ptyfs_free_tbl, M_UFSMNT);
332 }
333
334 /*
335 * Get a ptyfsnode from the free table, or allocate one.
336 * Removes the node from the free table.
337 */
338 struct ptyfsnode *
339 ptyfs_free_get(ptyfstype type, int pty, struct lwp *l)
340 {
341 struct ptyfs_hashhead *ppp;
342 struct ptyfsnode *pp;
343
344 simple_lock(&ptyfs_free_slock);
345 ppp = &ptyfs_free_tbl[PTYHASH(type, pty, ptyfs_free_mask)];
346 LIST_FOREACH(pp, ppp, ptyfs_hash) {
347 if (pty == pp->ptyfs_pty && pp->ptyfs_type == type) {
348 LIST_REMOVE(pp, ptyfs_hash);
349 simple_unlock(&ptyfs_free_slock);
350 return pp;
351 }
352 }
353 simple_unlock(&ptyfs_free_slock);
354
355 MALLOC(pp, void *, sizeof(struct ptyfsnode), M_TEMP, M_WAITOK);
356 pp->ptyfs_pty = pty;
357 pp->ptyfs_type = type;
358 pp->ptyfs_fileno = PTYFS_FILENO(pty, type);
359 ptyfs_getinfo(pp, l);
360 return pp;
361 }
362
363 struct vnode *
364 ptyfs_used_get(ptyfstype type, int pty, struct mount *mp)
365 {
366 struct ptyfs_hashhead *ppp;
367 struct ptyfsnode *pp;
368 struct vnode *vp;
369
370 loop:
371 simple_lock(&ptyfs_used_slock);
372 ppp = &ptyfs_used_tbl[PTYHASH(type, pty, ptyfs_used_mask)];
373 LIST_FOREACH(pp, ppp, ptyfs_hash) {
374 vp = PTYFSTOV(pp);
375 if (pty == pp->ptyfs_pty && pp->ptyfs_type == type &&
376 vp->v_mount == mp) {
377 simple_lock(&vp->v_interlock);
378 simple_unlock(&ptyfs_used_slock);
379 if (vget(vp, LK_EXCLUSIVE | LK_INTERLOCK))
380 goto loop;
381 return vp;
382 }
383 }
384 simple_unlock(&ptyfs_used_slock);
385 return NULL;
386 }
387
388 /*
389 * Insert the ptyfsnode into the used table and lock it.
390 */
391 static void
392 ptyfs_hashins(struct ptyfsnode *pp)
393 {
394 struct ptyfs_hashhead *ppp;
395
396 /* lock the ptyfsnode, then put it on the appropriate hash list */
397 lockmgr(&pp->ptyfs_vnode->v_lock, LK_EXCLUSIVE, NULL);
398
399 simple_lock(&ptyfs_used_slock);
400 ppp = &ptyfs_used_tbl[PTYHASH(pp->ptyfs_type, pp->ptyfs_pty,
401 ptyfs_used_mask)];
402 LIST_INSERT_HEAD(ppp, pp, ptyfs_hash);
403 simple_unlock(&ptyfs_used_slock);
404 }
405
406 /*
407 * Remove the ptyfsnode from the used table, and add it to the free table
408 */
409 static void
410 ptyfs_hashrem(struct ptyfsnode *pp)
411 {
412 struct ptyfs_hashhead *ppp;
413
414 simple_lock(&ptyfs_used_slock);
415 LIST_REMOVE(pp, ptyfs_hash);
416 simple_unlock(&ptyfs_used_slock);
417
418 simple_lock(&ptyfs_free_slock);
419 ppp = &ptyfs_free_tbl[PTYHASH(pp->ptyfs_type, pp->ptyfs_pty,
420 ptyfs_free_mask)];
421 LIST_INSERT_HEAD(ppp, pp, ptyfs_hash);
422 simple_unlock(&ptyfs_free_slock);
423 }
Cache object: d055a76b00d90951fc7b9245a28baed4
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