xref: /freebsd/sys/fs/pseudofs/pseudofs_vnops.c (revision 6b3455a7665208c366849f0b2b3bc916fb97516e)
1 /*-
2  * Copyright (c) 2001 Dag-Erling Co�dan Sm�rgrav
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer
10  *    in this position and unchanged.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  * 3. The name of the author may not be used to endorse or promote products
15  *    derived from this software without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27  *
28  *	$FreeBSD$
29  */
30 
31 #include <sys/param.h>
32 #include <sys/kernel.h>
33 #include <sys/systm.h>
34 #include <sys/ctype.h>
35 #include <sys/dirent.h>
36 #include <sys/fcntl.h>
37 #include <sys/limits.h>
38 #include <sys/lock.h>
39 #include <sys/mount.h>
40 #include <sys/mutex.h>
41 #include <sys/namei.h>
42 #include <sys/proc.h>
43 #include <sys/sbuf.h>
44 #include <sys/sx.h>
45 #include <sys/sysctl.h>
46 #include <sys/vnode.h>
47 
48 #include <fs/pseudofs/pseudofs.h>
49 #include <fs/pseudofs/pseudofs_internal.h>
50 
51 #if 0
52 #define PFS_TRACE(foo) \
53 	do { \
54 		printf("pseudofs: %s(): line %d: ", __func__, __LINE__); \
55 		printf foo ; \
56 		printf("\n"); \
57 	} while (0)
58 #define PFS_RETURN(err) \
59 	do { \
60 		printf("pseudofs: %s(): line %d: returning %d\n", \
61 		    __func__, __LINE__, err); \
62 		return (err); \
63 	} while (0)
64 #else
65 #define PFS_TRACE(foo) \
66 	do { /* nothing */ } while (0)
67 #define PFS_RETURN(err) \
68 	return (err)
69 #endif
70 
71 /*
72  * Returns non-zero if given file is visible to given process
73  */
74 static int
75 pfs_visible(struct thread *td, struct pfs_node *pn, pid_t pid)
76 {
77 	struct proc *proc;
78 	int r;
79 
80 	PFS_TRACE(("%s (pid: %d, req: %d)",
81 	    pn->pn_name, pid, td->td_proc->p_pid));
82 
83 	if (pn->pn_flags & PFS_DISABLED)
84 		PFS_RETURN (0);
85 
86 	r = 1;
87 	if (pid != NO_PID) {
88 		if ((proc = pfind(pid)) == NULL)
89 			PFS_RETURN (0);
90 		if (p_cansee(td, proc) != 0 ||
91 		    (pn->pn_vis != NULL && !(pn->pn_vis)(td, proc, pn)))
92 			r = 0;
93 		PROC_UNLOCK(proc);
94 	}
95 	PFS_RETURN (r);
96 }
97 
98 /*
99  * Verify permissions
100  */
101 static int
102 pfs_access(struct vop_access_args *va)
103 {
104 	struct vnode *vn = va->a_vp;
105 	struct vattr vattr;
106 	int error;
107 
108 	PFS_TRACE((((struct pfs_vdata *)vn->v_data)->pvd_pn->pn_name));
109 
110 	error = VOP_GETATTR(vn, &vattr, va->a_cred, va->a_td);
111 	if (error)
112 		PFS_RETURN (error);
113 	error = vaccess(vn->v_type, vattr.va_mode, vattr.va_uid,
114 	    vattr.va_gid, va->a_mode, va->a_cred, NULL);
115 	PFS_RETURN (error);
116 }
117 
118 /*
119  * Close a file or directory
120  */
121 static int
122 pfs_close(struct vop_close_args *va)
123 {
124 	struct vnode *vn = va->a_vp;
125 	struct pfs_vdata *pvd = (struct pfs_vdata *)vn->v_data;
126 	struct pfs_node *pn = pvd->pvd_pn;
127 	struct proc *proc;
128 	int error;
129 
130 	PFS_TRACE((pn->pn_name));
131 
132 	/*
133 	 * Do nothing unless this is the last close and the node has a
134 	 * last-close handler.
135 	 */
136 	if (vrefcnt(vn) > 1 || pn->pn_close == NULL)
137 		PFS_RETURN (0);
138 
139 	if (pvd->pvd_pid != NO_PID)
140 		proc = pfind(pvd->pvd_pid);
141 	else
142 		proc = NULL;
143 
144 	error = (pn->pn_close)(va->a_td, proc, pn);
145 
146 	if (proc != NULL)
147 		PROC_UNLOCK(proc);
148 
149 	PFS_RETURN (error);
150 }
151 
152 /*
153  * Get file attributes
154  */
155 static int
156 pfs_getattr(struct vop_getattr_args *va)
157 {
158 	struct vnode *vn = va->a_vp;
159 	struct pfs_vdata *pvd = (struct pfs_vdata *)vn->v_data;
160 	struct pfs_node *pn = pvd->pvd_pn;
161 	struct vattr *vap = va->a_vap;
162 	struct proc *proc;
163 	int error = 0;
164 
165 	PFS_TRACE((pn->pn_name));
166 
167 	if (!pfs_visible(curthread, pn, pvd->pvd_pid))
168 		PFS_RETURN (ENOENT);
169 
170 	VATTR_NULL(vap);
171 	vap->va_type = vn->v_type;
172 	vap->va_fileid = pn->pn_fileno;
173 	vap->va_flags = 0;
174 	vap->va_blocksize = PAGE_SIZE;
175 	vap->va_bytes = vap->va_size = 0;
176 	vap->va_fsid = vn->v_mount->mnt_stat.f_fsid.val[0];
177 	vap->va_nlink = 1;
178 	nanotime(&vap->va_ctime);
179 	vap->va_atime = vap->va_mtime = vap->va_ctime;
180 
181 	switch (pn->pn_type) {
182 	case pfstype_procdir:
183 	case pfstype_root:
184 	case pfstype_dir:
185 		vap->va_mode = 0555;
186 		break;
187 	case pfstype_file:
188 	case pfstype_symlink:
189 		vap->va_mode = 0444;
190 		break;
191 	default:
192 		printf("shouldn't be here!\n");
193 		vap->va_mode = 0;
194 		break;
195 	}
196 
197 	if (pvd->pvd_pid != NO_PID) {
198 		if ((proc = pfind(pvd->pvd_pid)) == NULL)
199 			PFS_RETURN (ENOENT);
200 		vap->va_uid = proc->p_ucred->cr_ruid;
201 		vap->va_gid = proc->p_ucred->cr_rgid;
202 		if (pn->pn_attr != NULL)
203 			error = (pn->pn_attr)(va->a_td, proc, pn, vap);
204 		PROC_UNLOCK(proc);
205 	} else {
206 		vap->va_uid = 0;
207 		vap->va_gid = 0;
208 	}
209 
210 	PFS_RETURN (error);
211 }
212 
213 /*
214  * Perform an ioctl
215  */
216 static int
217 pfs_ioctl(struct vop_ioctl_args *va)
218 {
219 	struct vnode *vn = va->a_vp;
220 	struct pfs_vdata *pvd = (struct pfs_vdata *)vn->v_data;
221 	struct pfs_node *pn = pvd->pvd_pn;
222 	struct proc *proc = NULL;
223 	int error;
224 
225 	PFS_TRACE(("%s: %lx", pn->pn_name, va->a_command));
226 
227 	if (vn->v_type != VREG)
228 		PFS_RETURN (EINVAL);
229 
230 	if (pn->pn_ioctl == NULL)
231 		PFS_RETURN (ENOTTY);
232 
233 	/*
234 	 * This is necessary because process' privileges may
235 	 * have changed since the open() call.
236 	 */
237 	if (!pfs_visible(curthread, pn, pvd->pvd_pid))
238 		PFS_RETURN (EIO);
239 
240 	/* XXX duplicates bits of pfs_visible() */
241 	if (pvd->pvd_pid != NO_PID) {
242 		if ((proc = pfind(pvd->pvd_pid)) == NULL)
243 			PFS_RETURN (EIO);
244 		_PHOLD(proc);
245 		PROC_UNLOCK(proc);
246 	}
247 
248 	error = (pn->pn_ioctl)(curthread, proc, pn, va->a_command, va->a_data);
249 
250 	if (proc != NULL)
251 		PRELE(proc);
252 
253 	PFS_RETURN (error);
254 }
255 
256 /*
257  * Perform getextattr
258  */
259 static int
260 pfs_getextattr(struct vop_getextattr_args *va)
261 {
262 	struct vnode *vn = va->a_vp;
263 	struct pfs_vdata *pvd = (struct pfs_vdata *)vn->v_data;
264 	struct pfs_node *pn = pvd->pvd_pn;
265 	struct proc *proc = NULL;
266 	int error;
267 
268 	PFS_TRACE((pd->pn_name));
269 
270 	if (!pfs_visible(curthread, pn, pvd->pvd_pid))
271 		PFS_RETURN (ENOENT);
272 
273 	if (pn->pn_getextattr == NULL)
274 		PFS_RETURN (EOPNOTSUPP);
275 
276 	/*
277 	 * This is necessary because either process' privileges may
278 	 * have changed since the open() call.
279 	 */
280 	if (!pfs_visible(curthread, pn, pvd->pvd_pid))
281 		PFS_RETURN (EIO);
282 
283 	/* XXX duplicates bits of pfs_visible() */
284 	if (pvd->pvd_pid != NO_PID) {
285 		if ((proc = pfind(pvd->pvd_pid)) == NULL)
286 			PFS_RETURN (EIO);
287 		_PHOLD(proc);
288 		PROC_UNLOCK(proc);
289 	}
290 
291 	error = (pn->pn_getextattr)(curthread, proc, pn, va->a_attrnamespace,
292 	    va->a_name, va->a_uio, va->a_size, va->a_cred);
293 
294 	if (proc != NULL)
295 		PRELE(proc);
296 
297 	PFS_RETURN (error);
298 }
299 
300 /*
301  * Look up a file or directory
302  *
303  * XXX NOTE!  pfs_lookup() has been hooked into vop_lookup_desc!  This
304  * will result in a lookup operation for a vnode which may already be
305  * cached, therefore we have to be careful to purge the VFS cache when
306  * reusing a vnode.
307  *
308  * This code will work, but is not really correct.  Normally we would hook
309  * vfs_cache_lookup() into vop_lookup_desc and hook pfs_lookup() into
310  * vop_cachedlookup_desc.
311  */
312 static int
313 pfs_lookup(struct vop_lookup_args *va)
314 {
315 	struct vnode *vn = va->a_dvp;
316 	struct vnode **vpp = va->a_vpp;
317 	struct componentname *cnp = va->a_cnp;
318 	struct pfs_vdata *pvd = (struct pfs_vdata *)vn->v_data;
319 	struct pfs_node *pd = pvd->pvd_pn;
320 	struct pfs_node *pn, *pdn = NULL;
321 	pid_t pid = pvd->pvd_pid;
322 	int lockparent;
323 	int wantparent;
324 	char *pname;
325 	int error, i, namelen;
326 
327 	PFS_TRACE(("%.*s", (int)cnp->cn_namelen, cnp->cn_nameptr));
328 
329 	cnp->cn_flags &= ~PDIRUNLOCK;
330 
331 	if (vn->v_type != VDIR)
332 		PFS_RETURN (ENOTDIR);
333 
334 	/*
335 	 * Don't support DELETE or RENAME.  CREATE is supported so
336 	 * that O_CREAT will work, but the lookup will still fail if
337 	 * the file does not exist.
338 	 */
339 	if (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)
340 		PFS_RETURN (EOPNOTSUPP);
341 
342 	/* shortcut: check if the name is too long */
343 	if (cnp->cn_namelen >= PFS_NAMELEN)
344 		PFS_RETURN (ENOENT);
345 
346 	/* check that parent directory is visisble... */
347 	if (!pfs_visible(curthread, pd, pvd->pvd_pid))
348 		PFS_RETURN (ENOENT);
349 
350 	lockparent = cnp->cn_flags & LOCKPARENT;
351 	wantparent = cnp->cn_flags & (LOCKPARENT | WANTPARENT);
352 
353 
354 	/* self */
355 	namelen = cnp->cn_namelen;
356 	pname = cnp->cn_nameptr;
357 	if (namelen == 1 && *pname == '.') {
358 		pn = pd;
359 		*vpp = vn;
360 		VREF(vn);
361 		PFS_RETURN (0);
362 	}
363 
364 	/* parent */
365 	if (cnp->cn_flags & ISDOTDOT) {
366 		if (pd->pn_type == pfstype_root)
367 			PFS_RETURN (EIO);
368 		VOP_UNLOCK(vn, 0, cnp->cn_thread);
369 		cnp->cn_flags |= PDIRUNLOCK;
370 
371 		KASSERT(pd->pn_parent, ("non-root directory has no parent"));
372 		/*
373 		 * This one is tricky.  Descendents of procdir nodes
374 		 * inherit their parent's process affinity, but
375 		 * there's no easy reverse mapping.  For simplicity,
376 		 * we assume that if this node is a procdir, its
377 		 * parent isn't (which is correct as long as
378 		 * descendents of procdir nodes are never procdir
379 		 * nodes themselves)
380 		 */
381 		if (pd->pn_type == pfstype_procdir)
382 			pid = NO_PID;
383 		pn = pd->pn_parent;
384 		goto got_pnode;
385 	}
386 
387 	/* named node */
388 	for (pn = pd->pn_nodes; pn != NULL; pn = pn->pn_next)
389 		if (pn->pn_type == pfstype_procdir)
390 			pdn = pn;
391 		else if (pn->pn_name[namelen] == '\0'
392 		    && bcmp(pname, pn->pn_name, namelen) == 0)
393 			goto got_pnode;
394 
395 	/* process dependent node */
396 	if ((pn = pdn) != NULL) {
397 		pid = 0;
398 		for (pid = 0, i = 0; i < namelen && isdigit(pname[i]); ++i)
399 			if ((pid = pid * 10 + pname[i] - '0') > PID_MAX)
400 				break;
401 		if (i == cnp->cn_namelen)
402 			goto got_pnode;
403 	}
404 
405 	PFS_RETURN (ENOENT);
406  got_pnode:
407 	if (pn != pd->pn_parent && !pn->pn_parent)
408 		pn->pn_parent = pd;
409 	if (!pfs_visible(curthread, pn, pvd->pvd_pid))
410 		PFS_RETURN (ENOENT);
411 
412 	error = pfs_vncache_alloc(vn->v_mount, vpp, pn, pid);
413 	if (error)
414 		PFS_RETURN (error);
415 
416 	if ((cnp->cn_flags & ISDOTDOT) && (cnp->cn_flags & ISLASTCN)
417 	    && lockparent) {
418 		vn_lock(vn, LK_EXCLUSIVE|LK_RETRY, cnp->cn_thread);
419 		cnp->cn_flags &= ~PDIRUNLOCK;
420 	}
421 	if (!((lockparent && (cnp->cn_flags & ISLASTCN)) ||
422 	    (cnp->cn_flags & ISDOTDOT)))
423 		VOP_UNLOCK(vn, 0, cnp->cn_thread);
424 
425 	/*
426 	 * XXX See comment at top of the routine.
427 	 */
428 	if (cnp->cn_flags & MAKEENTRY)
429 		cache_enter(vn, *vpp, cnp);
430 	PFS_RETURN (0);
431 }
432 
433 /*
434  * Open a file or directory.
435  */
436 static int
437 pfs_open(struct vop_open_args *va)
438 {
439 	struct vnode *vn = va->a_vp;
440 	struct pfs_vdata *pvd = (struct pfs_vdata *)vn->v_data;
441 	struct pfs_node *pn = pvd->pvd_pn;
442 	int mode = va->a_mode;
443 
444 	PFS_TRACE(("%s (mode 0x%x)", pn->pn_name, mode));
445 
446 	/*
447 	 * check if the file is visible to the caller
448 	 *
449 	 * XXX Not sure if this is necessary, as the VFS system calls
450 	 * XXX pfs_lookup() and pfs_access() first, and pfs_lookup()
451 	 * XXX calls pfs_visible().  There's a race condition here, but
452 	 * XXX calling pfs_visible() from here doesn't really close it,
453 	 * XXX and the only consequence of that race is an EIO further
454 	 * XXX down the line.
455 	 */
456 	if (!pfs_visible(va->a_td, pn, pvd->pvd_pid))
457 		PFS_RETURN (ENOENT);
458 
459 	/* check if the requested mode is permitted */
460 	if (((mode & FREAD) && !(mode & PFS_RD)) ||
461 	    ((mode & FWRITE) && !(mode & PFS_WR)))
462 		PFS_RETURN (EPERM);
463 
464 	/* we don't support locking */
465 	if ((mode & O_SHLOCK) || (mode & O_EXLOCK))
466 		PFS_RETURN (EOPNOTSUPP);
467 
468 	PFS_RETURN (0);
469 }
470 
471 /*
472  * Read from a file
473  */
474 static int
475 pfs_read(struct vop_read_args *va)
476 {
477 	struct vnode *vn = va->a_vp;
478 	struct pfs_vdata *pvd = (struct pfs_vdata *)vn->v_data;
479 	struct pfs_node *pn = pvd->pvd_pn;
480 	struct uio *uio = va->a_uio;
481 	struct proc *proc = NULL;
482 	struct sbuf *sb = NULL;
483 	int error;
484 	unsigned int buflen, offset, resid;
485 
486 	PFS_TRACE((pn->pn_name));
487 
488 	if (vn->v_type != VREG)
489 		PFS_RETURN (EINVAL);
490 
491 	if (!(pn->pn_flags & PFS_RD))
492 		PFS_RETURN (EBADF);
493 
494 	if (pn->pn_func == NULL)
495 		PFS_RETURN (EIO);
496 
497 	/*
498 	 * This is necessary because either process' privileges may
499 	 * have changed since the open() call.
500 	 */
501 	if (!pfs_visible(curthread, pn, pvd->pvd_pid))
502 		PFS_RETURN (EIO);
503 
504 	/* XXX duplicates bits of pfs_visible() */
505 	if (pvd->pvd_pid != NO_PID) {
506 		if ((proc = pfind(pvd->pvd_pid)) == NULL)
507 			PFS_RETURN (EIO);
508 		_PHOLD(proc);
509 		PROC_UNLOCK(proc);
510 	}
511 
512 	if (pn->pn_flags & PFS_RAWRD) {
513 		error = (pn->pn_func)(curthread, proc, pn, NULL, uio);
514 		if (proc != NULL)
515 			PRELE(proc);
516 		PFS_RETURN (error);
517 	}
518 
519 	/* Beaucoup sanity checks so we don't ask for bogus allocation. */
520 	if (uio->uio_offset < 0 || uio->uio_resid < 0 ||
521 	    (offset = uio->uio_offset) != uio->uio_offset ||
522 	    (resid = uio->uio_resid) != uio->uio_resid ||
523 	    (buflen = offset + resid) < offset || buflen > INT_MAX) {
524 		if (proc != NULL)
525 			PRELE(proc);
526 		PFS_RETURN (EINVAL);
527 	}
528 	if (buflen > MAXPHYS) {
529 		if (proc != NULL)
530 			PRELE(proc);
531 		PFS_RETURN (EIO);
532 	}
533 	sb = sbuf_new(sb, NULL, buflen, 0);
534 	if (sb == NULL) {
535 		if (proc != NULL)
536 			PRELE(proc);
537 		PFS_RETURN (EIO);
538 	}
539 
540 	error = (pn->pn_func)(curthread, proc, pn, sb, uio);
541 
542 	if (proc != NULL)
543 		PRELE(proc);
544 
545 	if (error) {
546 		sbuf_delete(sb);
547 		PFS_RETURN (error);
548 	}
549 
550 	sbuf_finish(sb);
551 	error = uiomove_frombuf(sbuf_data(sb), sbuf_len(sb), uio);
552 	sbuf_delete(sb);
553 	PFS_RETURN (error);
554 }
555 
556 /*
557  * Iterate through directory entries
558  */
559 static int
560 pfs_iterate(struct thread *td, pid_t pid, struct pfs_node *pd,
561 	    struct pfs_node **pn, struct proc **p)
562 {
563 	sx_assert(&allproc_lock, SX_LOCKED);
564  again:
565 	if (*pn == NULL) {
566 		/* first node */
567 		*pn = pd->pn_nodes;
568 	} else if ((*pn)->pn_type != pfstype_procdir) {
569 		/* next node */
570 		*pn = (*pn)->pn_next;
571 	}
572 	if (*pn != NULL && (*pn)->pn_type == pfstype_procdir) {
573 		/* next process */
574 		if (*p == NULL)
575 			*p = LIST_FIRST(&allproc);
576 		else
577 			*p = LIST_NEXT(*p, p_list);
578 		/* out of processes: next node */
579 		if (*p == NULL)
580 			*pn = (*pn)->pn_next;
581 	}
582 
583 	if ((*pn) == NULL)
584 		return (-1);
585 
586 	if (!pfs_visible(td, *pn, *p ? (*p)->p_pid : pid))
587 		goto again;
588 
589 	return (0);
590 }
591 
592 /*
593  * Return directory entries.
594  */
595 static int
596 pfs_readdir(struct vop_readdir_args *va)
597 {
598 	struct vnode *vn = va->a_vp;
599 	struct pfs_info *pi = (struct pfs_info *)vn->v_mount->mnt_data;
600 	struct pfs_vdata *pvd = (struct pfs_vdata *)vn->v_data;
601 	struct pfs_node *pd = pvd->pvd_pn;
602 	pid_t pid = pvd->pvd_pid;
603 	struct pfs_node *pn;
604 	struct dirent entry;
605 	struct uio *uio;
606 	struct proc *p;
607 	off_t offset;
608 	int error, i, resid;
609 	struct sbuf sb;
610 
611 	PFS_TRACE((pd->pn_name));
612 
613 	if (vn->v_type != VDIR)
614 		PFS_RETURN (ENOTDIR);
615 	uio = va->a_uio;
616 
617 	/* check if the directory is visible to the caller */
618 	if (!pfs_visible(curthread, pd, pid))
619 		PFS_RETURN (ENOENT);
620 
621 	/* only allow reading entire entries */
622 	offset = uio->uio_offset;
623 	resid = uio->uio_resid;
624 	if (offset < 0 || offset % PFS_DELEN != 0 || resid < PFS_DELEN)
625 		PFS_RETURN (EINVAL);
626 
627 	if (sbuf_new(&sb, NULL, resid, SBUF_FIXEDLEN) == NULL)
628 		PFS_RETURN (ENOMEM);
629 
630 	/* skip unwanted entries */
631 	sx_slock(&allproc_lock);
632 	for (pn = NULL, p = NULL; offset > 0; offset -= PFS_DELEN)
633 		if (pfs_iterate(curthread, pid, pd, &pn, &p) == -1) {
634 			/* nothing left... */
635 			sx_sunlock(&allproc_lock);
636 			sbuf_delete(&sb);
637 			PFS_RETURN (0);
638 		}
639 
640 	/* fill in entries */
641 	entry.d_reclen = PFS_DELEN;
642 	while (pfs_iterate(curthread, pid, pd, &pn, &p) != -1 && resid > 0) {
643 		if (!pn->pn_parent)
644 			pn->pn_parent = pd;
645 		if (!pn->pn_fileno)
646 			pfs_fileno_alloc(pi, pn);
647 		if (pid != NO_PID)
648 			entry.d_fileno = pn->pn_fileno * NO_PID + pid;
649 		else
650 			entry.d_fileno = pn->pn_fileno;
651 		/* PFS_DELEN was picked to fit PFS_NAMLEN */
652 		for (i = 0; i < PFS_NAMELEN - 1 && pn->pn_name[i] != '\0'; ++i)
653 			entry.d_name[i] = pn->pn_name[i];
654 		entry.d_name[i] = 0;
655 		entry.d_namlen = i;
656 		switch (pn->pn_type) {
657 		case pfstype_procdir:
658 			KASSERT(p != NULL,
659 			    ("reached procdir node with p == NULL"));
660 			entry.d_fileno = pn->pn_fileno * NO_PID + p->p_pid;
661 			entry.d_namlen = snprintf(entry.d_name,
662 			    PFS_NAMELEN, "%d", p->p_pid);
663 			/* fall through */
664 		case pfstype_root:
665 		case pfstype_dir:
666 		case pfstype_this:
667 		case pfstype_parent:
668 			entry.d_type = DT_DIR;
669 			break;
670 		case pfstype_file:
671 			entry.d_type = DT_REG;
672 			break;
673 		case pfstype_symlink:
674 			entry.d_type = DT_LNK;
675 			break;
676 		default:
677 			panic("%s has unexpected node type: %d", pn->pn_name, pn->pn_type);
678 		}
679 		PFS_TRACE((entry.d_name));
680 		sbuf_bcat(&sb, &entry, PFS_DELEN);
681 		offset += PFS_DELEN;
682 		resid -= PFS_DELEN;
683 	}
684 	sx_sunlock(&allproc_lock);
685 	sbuf_finish(&sb);
686 	error = uiomove(sbuf_data(&sb), sbuf_len(&sb), uio);
687 	sbuf_delete(&sb);
688 	PFS_RETURN (error);
689 }
690 
691 /*
692  * Read a symbolic link
693  */
694 static int
695 pfs_readlink(struct vop_readlink_args *va)
696 {
697 	struct vnode *vn = va->a_vp;
698 	struct pfs_vdata *pvd = (struct pfs_vdata *)vn->v_data;
699 	struct pfs_node *pn = pvd->pvd_pn;
700 	struct uio *uio = va->a_uio;
701 	struct proc *proc = NULL;
702 	char buf[MAXPATHLEN];
703 	struct sbuf sb;
704 	int error;
705 
706 	PFS_TRACE((pn->pn_name));
707 
708 	if (vn->v_type != VLNK)
709 		PFS_RETURN (EINVAL);
710 
711 	if (pn->pn_func == NULL)
712 		PFS_RETURN (EIO);
713 
714 	if (pvd->pvd_pid != NO_PID) {
715 		if ((proc = pfind(pvd->pvd_pid)) == NULL)
716 			PFS_RETURN (EIO);
717 		_PHOLD(proc);
718 		PROC_UNLOCK(proc);
719 	}
720 
721 	/* sbuf_new() can't fail with a static buffer */
722 	sbuf_new(&sb, buf, sizeof buf, 0);
723 
724 	error = (pn->pn_func)(curthread, proc, pn, &sb, NULL);
725 
726 	if (proc != NULL)
727 		PRELE(proc);
728 
729 	if (error) {
730 		sbuf_delete(&sb);
731 		PFS_RETURN (error);
732 	}
733 
734 	sbuf_finish(&sb);
735 	error = uiomove_frombuf(sbuf_data(&sb), sbuf_len(&sb), uio);
736 	sbuf_delete(&sb);
737 	PFS_RETURN (error);
738 }
739 
740 /*
741  * Reclaim a vnode
742  */
743 static int
744 pfs_reclaim(struct vop_reclaim_args *va)
745 {
746 	PFS_TRACE((((struct pfs_vdata *)va->a_vp->v_data)->pvd_pn->pn_name));
747 
748 	return (pfs_vncache_free(va->a_vp));
749 }
750 
751 /*
752  * Set attributes
753  */
754 static int
755 pfs_setattr(struct vop_setattr_args *va)
756 {
757 	PFS_TRACE((((struct pfs_vdata *)va->a_vp->v_data)->pvd_pn->pn_name));
758 
759 	PFS_RETURN (EOPNOTSUPP);
760 }
761 
762 /*
763  * Read from a file
764  */
765 static int
766 pfs_write(struct vop_read_args *va)
767 {
768 	struct vnode *vn = va->a_vp;
769 	struct pfs_vdata *pvd = (struct pfs_vdata *)vn->v_data;
770 	struct pfs_node *pn = pvd->pvd_pn;
771 	struct uio *uio = va->a_uio;
772 	struct proc *proc = NULL;
773 	struct sbuf sb;
774 	int error;
775 
776 	PFS_TRACE((pn->pn_name));
777 
778 	if (vn->v_type != VREG)
779 		PFS_RETURN (EINVAL);
780 
781 	if (!(pn->pn_flags & PFS_WR))
782 		PFS_RETURN (EBADF);
783 
784 	if (pn->pn_func == NULL)
785 		PFS_RETURN (EIO);
786 
787 	/*
788 	 * This is necessary because either process' privileges may
789 	 * have changed since the open() call.
790 	 */
791 	if (!pfs_visible(curthread, pn, pvd->pvd_pid))
792 		PFS_RETURN (EIO);
793 
794 	/* XXX duplicates bits of pfs_visible() */
795 	if (pvd->pvd_pid != NO_PID) {
796 		if ((proc = pfind(pvd->pvd_pid)) == NULL)
797 			PFS_RETURN (EIO);
798 		_PHOLD(proc);
799 		PROC_UNLOCK(proc);
800 	}
801 
802 	if (pn->pn_flags & PFS_RAWWR) {
803 		error = (pn->pn_func)(curthread, proc, pn, NULL, uio);
804 		if (proc != NULL)
805 			PRELE(proc);
806 		PFS_RETURN (error);
807 	}
808 
809 	sbuf_uionew(&sb, uio, &error);
810 	if (error)
811 		PFS_RETURN (error);
812 
813 	error = (pn->pn_func)(curthread, proc, pn, &sb, uio);
814 
815 	if (proc != NULL)
816 		PRELE(proc);
817 
818 	sbuf_delete(&sb);
819 	PFS_RETURN (error);
820 }
821 
822 /*
823  * Vnode operations
824  */
825 vop_t **pfs_vnodeop_p;
826 static struct vnodeopv_entry_desc pfs_vnodeop_entries[] = {
827 	{ &vop_default_desc,		(vop_t *)vop_defaultop	},
828 	{ &vop_access_desc,		(vop_t *)pfs_access	},
829 	{ &vop_close_desc,		(vop_t *)pfs_close	},
830 	{ &vop_create_desc,		(vop_t *)vop_eopnotsupp	},
831 	{ &vop_getattr_desc,		(vop_t *)pfs_getattr	},
832 	{ &vop_getextattr_desc,		(vop_t *)pfs_getextattr	},
833 	{ &vop_ioctl_desc,		(vop_t *)pfs_ioctl	},
834 	{ &vop_link_desc,		(vop_t *)vop_eopnotsupp	},
835 	{ &vop_lookup_desc,		(vop_t *)pfs_lookup	},
836 	{ &vop_mkdir_desc,		(vop_t *)vop_eopnotsupp	},
837 	{ &vop_mknod_desc,		(vop_t *)vop_eopnotsupp	},
838 	{ &vop_open_desc,		(vop_t *)pfs_open	},
839 	{ &vop_read_desc,		(vop_t *)pfs_read	},
840 	{ &vop_readdir_desc,		(vop_t *)pfs_readdir	},
841 	{ &vop_readlink_desc,		(vop_t *)pfs_readlink	},
842 	{ &vop_reclaim_desc,		(vop_t *)pfs_reclaim	},
843 	{ &vop_remove_desc,		(vop_t *)vop_eopnotsupp	},
844 	{ &vop_rename_desc,		(vop_t *)vop_eopnotsupp	},
845 	{ &vop_rmdir_desc,		(vop_t *)vop_eopnotsupp	},
846 	{ &vop_setattr_desc,		(vop_t *)pfs_setattr	},
847 	{ &vop_symlink_desc,		(vop_t *)vop_eopnotsupp	},
848 	{ &vop_write_desc,		(vop_t *)pfs_write	},
849 	/* XXX I've probably forgotten a few that need vop_eopnotsupp */
850 	{ NULL,				(vop_t *)NULL		}
851 };
852 
853 static struct vnodeopv_desc pfs_vnodeop_opv_desc =
854 	{ &pfs_vnodeop_p, pfs_vnodeop_entries };
855 
856 VNODEOP_SET(pfs_vnodeop_opv_desc);
857