1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 2001 Dag-Erling Smørgrav
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer
12 * in this position and unchanged.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. The name of the author may not be used to endorse or promote products
17 * derived from this software without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31 #include <sys/cdefs.h>
32 #include "opt_pseudofs.h"
33
34 #include <sys/param.h>
35 #include <sys/kernel.h>
36 #include <sys/systm.h>
37 #include <sys/ctype.h>
38 #include <sys/dirent.h>
39 #include <sys/fcntl.h>
40 #include <sys/limits.h>
41 #include <sys/lock.h>
42 #include <sys/malloc.h>
43 #include <sys/mount.h>
44 #include <sys/mutex.h>
45 #include <sys/namei.h>
46 #include <sys/proc.h>
47 #include <sys/sbuf.h>
48 #include <sys/sx.h>
49 #include <sys/sysctl.h>
50 #include <sys/vnode.h>
51
52 #include <fs/pseudofs/pseudofs.h>
53 #include <fs/pseudofs/pseudofs_internal.h>
54
55 #define KASSERT_PN_IS_DIR(pn) \
56 KASSERT((pn)->pn_type == pfstype_root || \
57 (pn)->pn_type == pfstype_dir || \
58 (pn)->pn_type == pfstype_procdir, \
59 ("%s(): VDIR vnode refers to non-directory pfs_node", __func__))
60
61 #define KASSERT_PN_IS_FILE(pn) \
62 KASSERT((pn)->pn_type == pfstype_file, \
63 ("%s(): VREG vnode refers to non-file pfs_node", __func__))
64
65 #define KASSERT_PN_IS_LINK(pn) \
66 KASSERT((pn)->pn_type == pfstype_symlink, \
67 ("%s(): VLNK vnode refers to non-link pfs_node", __func__))
68
69 #define PFS_MAXBUFSIZ 1024 * 1024
70
71 /*
72 * Returns the fileno, adjusted for target pid
73 */
74 static uint32_t
pn_fileno(struct pfs_node * pn,pid_t pid)75 pn_fileno(struct pfs_node *pn, pid_t pid)
76 {
77
78 KASSERT(pn->pn_fileno > 0,
79 ("%s(): no fileno allocated", __func__));
80 if (pid != NO_PID)
81 return (pn->pn_fileno * NO_PID + pid);
82 return (pn->pn_fileno);
83 }
84
85 /*
86 * Returns non-zero if given file is visible to given thread.
87 */
88 static int
pfs_visible_proc(struct thread * td,struct pfs_node * pn,struct proc * proc)89 pfs_visible_proc(struct thread *td, struct pfs_node *pn, struct proc *proc)
90 {
91
92 if (proc == NULL)
93 return (0);
94
95 PROC_LOCK_ASSERT(proc, MA_OWNED);
96
97 if ((proc->p_flag & P_WEXIT) != 0)
98 return (0);
99 if (p_cansee(td, proc) != 0)
100 return (0);
101 return (pn_vis(td, proc, pn));
102 }
103
104 static int
pfs_visible(struct thread * td,struct pfs_node * pn,pid_t pid,struct proc ** p)105 pfs_visible(struct thread *td, struct pfs_node *pn, pid_t pid,
106 struct proc **p)
107 {
108 struct proc *proc;
109
110 PFS_TRACE(("%s (pid: %d, req: %d)",
111 pn->pn_name, pid, td->td_proc->p_pid));
112
113 if (p)
114 *p = NULL;
115 if (pid == NO_PID)
116 PFS_RETURN (pn_vis(td, NULL, pn));
117 proc = pfind(pid);
118 if (proc == NULL)
119 PFS_RETURN (0);
120 if (pfs_visible_proc(td, pn, proc)) {
121 if (p)
122 *p = proc;
123 else
124 PROC_UNLOCK(proc);
125 PFS_RETURN (1);
126 }
127 PROC_UNLOCK(proc);
128 PFS_RETURN (0);
129 }
130
131 static int
pfs_lookup_proc(pid_t pid,struct proc ** p)132 pfs_lookup_proc(pid_t pid, struct proc **p)
133 {
134 struct proc *proc;
135
136 proc = pfind(pid);
137 if (proc == NULL)
138 return (0);
139 if ((proc->p_flag & P_WEXIT) != 0) {
140 PROC_UNLOCK(proc);
141 return (0);
142 }
143 _PHOLD(proc);
144 PROC_UNLOCK(proc);
145 *p = proc;
146 return (1);
147 }
148
149 /*
150 * Verify permissions
151 */
152 static int
pfs_access(struct vop_access_args * va)153 pfs_access(struct vop_access_args *va)
154 {
155 struct vnode *vn = va->a_vp;
156 struct pfs_vdata *pvd = vn->v_data;
157 struct vattr vattr;
158 int error;
159
160 PFS_TRACE(("%s", pvd->pvd_pn->pn_name));
161 (void)pvd;
162
163 error = VOP_GETATTR(vn, &vattr, va->a_cred);
164 if (error)
165 PFS_RETURN (error);
166 error = vaccess(vn->v_type, vattr.va_mode, vattr.va_uid, vattr.va_gid,
167 va->a_accmode, va->a_cred);
168 PFS_RETURN (error);
169 }
170
171 /*
172 * Close a file or directory
173 */
174 static int
pfs_close(struct vop_close_args * va)175 pfs_close(struct vop_close_args *va)
176 {
177 struct vnode *vn = va->a_vp;
178 struct pfs_vdata *pvd = vn->v_data;
179 struct pfs_node *pn = pvd->pvd_pn;
180 struct proc *proc;
181 int error;
182
183 PFS_TRACE(("%s", pn->pn_name));
184 pfs_assert_not_owned(pn);
185
186 /*
187 * Do nothing unless this is the last close and the node has a
188 * last-close handler.
189 */
190 if (vrefcnt(vn) > 1 || pn->pn_close == NULL)
191 PFS_RETURN (0);
192
193 if (pvd->pvd_pid != NO_PID) {
194 proc = pfind(pvd->pvd_pid);
195 } else {
196 proc = NULL;
197 }
198
199 error = pn_close(va->a_td, proc, pn);
200
201 if (proc != NULL)
202 PROC_UNLOCK(proc);
203
204 PFS_RETURN (error);
205 }
206
207 /*
208 * Get file attributes
209 */
210 static int
pfs_getattr(struct vop_getattr_args * va)211 pfs_getattr(struct vop_getattr_args *va)
212 {
213 struct vnode *vn = va->a_vp;
214 struct pfs_vdata *pvd = vn->v_data;
215 struct pfs_node *pn = pvd->pvd_pn;
216 struct vattr *vap = va->a_vap;
217 struct proc *proc;
218 int error = 0;
219
220 PFS_TRACE(("%s", pn->pn_name));
221 pfs_assert_not_owned(pn);
222
223 if (!pfs_visible(curthread, pn, pvd->pvd_pid, &proc))
224 PFS_RETURN (ENOENT);
225
226 vap->va_type = vn->v_type;
227 vap->va_fileid = pn_fileno(pn, pvd->pvd_pid);
228 vap->va_flags = 0;
229 vap->va_blocksize = PAGE_SIZE;
230 vap->va_bytes = vap->va_size = 0;
231 vap->va_filerev = 0;
232 vap->va_fsid = vn->v_mount->mnt_stat.f_fsid.val[0];
233 vap->va_nlink = 1;
234 nanotime(&vap->va_ctime);
235 vap->va_atime = vap->va_mtime = vap->va_ctime;
236
237 switch (pn->pn_type) {
238 case pfstype_procdir:
239 case pfstype_root:
240 case pfstype_dir:
241 #if 0
242 pfs_lock(pn);
243 /* compute link count */
244 pfs_unlock(pn);
245 #endif
246 vap->va_mode = 0555;
247 break;
248 case pfstype_file:
249 case pfstype_symlink:
250 vap->va_mode = 0444;
251 break;
252 default:
253 printf("shouldn't be here!\n");
254 vap->va_mode = 0;
255 break;
256 }
257
258 if (proc != NULL) {
259 vap->va_uid = proc->p_ucred->cr_ruid;
260 vap->va_gid = proc->p_ucred->cr_rgid;
261 } else {
262 vap->va_uid = 0;
263 vap->va_gid = 0;
264 }
265
266 if (pn->pn_attr != NULL)
267 error = pn_attr(curthread, proc, pn, vap);
268
269 if(proc != NULL)
270 PROC_UNLOCK(proc);
271
272 PFS_RETURN (error);
273 }
274
275 /*
276 * Perform an ioctl
277 */
278 static int
pfs_ioctl(struct vop_ioctl_args * va)279 pfs_ioctl(struct vop_ioctl_args *va)
280 {
281 struct vnode *vn;
282 struct pfs_vdata *pvd;
283 struct pfs_node *pn;
284 struct proc *proc;
285 int error;
286
287 vn = va->a_vp;
288 vn_lock(vn, LK_SHARED | LK_RETRY);
289 if (VN_IS_DOOMED(vn)) {
290 VOP_UNLOCK(vn);
291 return (EBADF);
292 }
293 pvd = vn->v_data;
294 pn = pvd->pvd_pn;
295
296 PFS_TRACE(("%s: %lx", pn->pn_name, va->a_command));
297 pfs_assert_not_owned(pn);
298
299 if (vn->v_type != VREG) {
300 VOP_UNLOCK(vn);
301 PFS_RETURN (EINVAL);
302 }
303 KASSERT_PN_IS_FILE(pn);
304
305 if (pn->pn_ioctl == NULL) {
306 VOP_UNLOCK(vn);
307 PFS_RETURN (ENOTTY);
308 }
309
310 /*
311 * This is necessary because process' privileges may
312 * have changed since the open() call.
313 */
314 if (!pfs_visible(curthread, pn, pvd->pvd_pid, &proc)) {
315 VOP_UNLOCK(vn);
316 PFS_RETURN (EIO);
317 }
318
319 error = pn_ioctl(curthread, proc, pn, va->a_command, va->a_data);
320
321 if (proc != NULL)
322 PROC_UNLOCK(proc);
323
324 VOP_UNLOCK(vn);
325 PFS_RETURN (error);
326 }
327
328 /*
329 * Perform getextattr
330 */
331 static int
pfs_getextattr(struct vop_getextattr_args * va)332 pfs_getextattr(struct vop_getextattr_args *va)
333 {
334 struct vnode *vn = va->a_vp;
335 struct pfs_vdata *pvd = vn->v_data;
336 struct pfs_node *pn = pvd->pvd_pn;
337 struct proc *proc;
338 int error;
339
340 PFS_TRACE(("%s", pn->pn_name));
341 pfs_assert_not_owned(pn);
342
343 /*
344 * This is necessary because either process' privileges may
345 * have changed since the open() call.
346 */
347 if (!pfs_visible(curthread, pn, pvd->pvd_pid, &proc))
348 PFS_RETURN (EIO);
349
350 if (pn->pn_getextattr == NULL)
351 error = EOPNOTSUPP;
352 else
353 error = pn_getextattr(curthread, proc, pn,
354 va->a_attrnamespace, va->a_name, va->a_uio,
355 va->a_size, va->a_cred);
356
357 if (proc != NULL)
358 PROC_UNLOCK(proc);
359
360 PFS_RETURN (error);
361 }
362
363 /*
364 * Convert a vnode to its component name
365 */
366 static int
pfs_vptocnp(struct vop_vptocnp_args * ap)367 pfs_vptocnp(struct vop_vptocnp_args *ap)
368 {
369 struct vnode *vp = ap->a_vp;
370 struct vnode **dvp = ap->a_vpp;
371 struct pfs_vdata *pvd = vp->v_data;
372 struct pfs_node *pd = pvd->pvd_pn;
373 struct pfs_node *pn;
374 struct mount *mp;
375 char *buf = ap->a_buf;
376 size_t *buflen = ap->a_buflen;
377 char pidbuf[PFS_NAMELEN];
378 pid_t pid = pvd->pvd_pid;
379 int len, i, error, locked;
380
381 i = *buflen;
382 error = 0;
383
384 pfs_lock(pd);
385
386 if (vp->v_type == VDIR && pd->pn_type == pfstype_root) {
387 *dvp = vp;
388 vhold(*dvp);
389 pfs_unlock(pd);
390 PFS_RETURN (0);
391 } else if (vp->v_type == VDIR && pd->pn_type == pfstype_procdir) {
392 len = snprintf(pidbuf, sizeof(pidbuf), "%d", pid);
393 i -= len;
394 if (i < 0) {
395 error = ENOMEM;
396 goto failed;
397 }
398 bcopy(pidbuf, buf + i, len);
399 } else {
400 len = strlen(pd->pn_name);
401 i -= len;
402 if (i < 0) {
403 error = ENOMEM;
404 goto failed;
405 }
406 bcopy(pd->pn_name, buf + i, len);
407 }
408
409 pn = pd->pn_parent;
410 pfs_unlock(pd);
411
412 mp = vp->v_mount;
413 error = vfs_busy(mp, 0);
414 if (error)
415 return (error);
416
417 /*
418 * vp is held by caller.
419 */
420 locked = VOP_ISLOCKED(vp);
421 VOP_UNLOCK(vp);
422
423 error = pfs_vncache_alloc(mp, dvp, pn, pid);
424 if (error) {
425 vn_lock(vp, locked | LK_RETRY);
426 vfs_unbusy(mp);
427 PFS_RETURN(error);
428 }
429
430 *buflen = i;
431 VOP_UNLOCK(*dvp);
432 vn_lock(vp, locked | LK_RETRY);
433 vfs_unbusy(mp);
434
435 PFS_RETURN (0);
436 failed:
437 pfs_unlock(pd);
438 PFS_RETURN(error);
439 }
440
441 /*
442 * Look up a file or directory
443 */
444 static int
pfs_lookup(struct vop_cachedlookup_args * va)445 pfs_lookup(struct vop_cachedlookup_args *va)
446 {
447 struct vnode *vn = va->a_dvp;
448 struct vnode **vpp = va->a_vpp;
449 struct componentname *cnp = va->a_cnp;
450 struct pfs_vdata *pvd = vn->v_data;
451 struct pfs_node *pd = pvd->pvd_pn;
452 struct pfs_node *pn, *pdn = NULL;
453 struct mount *mp;
454 pid_t pid = pvd->pvd_pid;
455 char *pname;
456 int error, i, namelen, visible;
457
458 PFS_TRACE(("%.*s", (int)cnp->cn_namelen, cnp->cn_nameptr));
459 pfs_assert_not_owned(pd);
460
461 if (vn->v_type != VDIR)
462 PFS_RETURN (ENOTDIR);
463 KASSERT_PN_IS_DIR(pd);
464
465 /*
466 * Don't support DELETE or RENAME. CREATE is supported so
467 * that O_CREAT will work, but the lookup will still fail if
468 * the file does not exist.
469 */
470 if ((cnp->cn_flags & ISLASTCN) &&
471 (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME))
472 PFS_RETURN (EOPNOTSUPP);
473
474 /* shortcut: check if the name is too long */
475 if (cnp->cn_namelen >= PFS_NAMELEN)
476 PFS_RETURN (ENOENT);
477
478 /* check that parent directory is visible... */
479 if (!pfs_visible(curthread, pd, pvd->pvd_pid, NULL))
480 PFS_RETURN (ENOENT);
481
482 /* self */
483 namelen = cnp->cn_namelen;
484 pname = cnp->cn_nameptr;
485 if (namelen == 1 && pname[0] == '.') {
486 pn = pd;
487 *vpp = vn;
488 VREF(vn);
489 PFS_RETURN (0);
490 }
491
492 mp = vn->v_mount;
493
494 /* parent */
495 if (cnp->cn_flags & ISDOTDOT) {
496 if (pd->pn_type == pfstype_root)
497 PFS_RETURN (EIO);
498 error = vfs_busy(mp, MBF_NOWAIT);
499 if (error != 0) {
500 vfs_ref(mp);
501 VOP_UNLOCK(vn);
502 error = vfs_busy(mp, 0);
503 vn_lock(vn, LK_EXCLUSIVE | LK_RETRY);
504 vfs_rel(mp);
505 if (error != 0)
506 PFS_RETURN(ENOENT);
507 if (VN_IS_DOOMED(vn)) {
508 vfs_unbusy(mp);
509 PFS_RETURN(ENOENT);
510 }
511 }
512 VOP_UNLOCK(vn);
513 KASSERT(pd->pn_parent != NULL,
514 ("%s(): non-root directory has no parent", __func__));
515 /*
516 * This one is tricky. Descendents of procdir nodes
517 * inherit their parent's process affinity, but
518 * there's no easy reverse mapping. For simplicity,
519 * we assume that if this node is a procdir, its
520 * parent isn't (which is correct as long as
521 * descendents of procdir nodes are never procdir
522 * nodes themselves)
523 */
524 if (pd->pn_type == pfstype_procdir)
525 pid = NO_PID;
526 pfs_lock(pd);
527 pn = pd->pn_parent;
528 pfs_unlock(pd);
529 goto got_pnode;
530 }
531
532 pfs_lock(pd);
533
534 /* named node */
535 for (pn = pd->pn_nodes; pn != NULL; pn = pn->pn_next)
536 if (pn->pn_type == pfstype_procdir)
537 pdn = pn;
538 else if (strncmp(pname, pn->pn_name, namelen) == 0 &&
539 pn->pn_name[namelen] == '\0') {
540 pfs_unlock(pd);
541 goto got_pnode;
542 }
543
544 /* process dependent node */
545 if ((pn = pdn) != NULL) {
546 pid = 0;
547 for (pid = 0, i = 0; i < namelen && isdigit(pname[i]); ++i)
548 if ((pid = pid * 10 + pname[i] - '0') > PID_MAX)
549 break;
550 if (i == cnp->cn_namelen) {
551 pfs_unlock(pd);
552 goto got_pnode;
553 }
554 }
555
556 pfs_unlock(pd);
557
558 PFS_RETURN (ENOENT);
559
560 got_pnode:
561 pfs_assert_not_owned(pd);
562 pfs_assert_not_owned(pn);
563 visible = pfs_visible(curthread, pn, pid, NULL);
564 if (!visible) {
565 error = ENOENT;
566 goto failed;
567 }
568
569 error = pfs_vncache_alloc(mp, vpp, pn, pid);
570 if (error)
571 goto failed;
572
573 if (cnp->cn_flags & ISDOTDOT) {
574 vfs_unbusy(mp);
575 vn_lock(vn, LK_EXCLUSIVE | LK_RETRY);
576 if (VN_IS_DOOMED(vn)) {
577 vput(*vpp);
578 *vpp = NULL;
579 PFS_RETURN(ENOENT);
580 }
581 }
582 if (cnp->cn_flags & MAKEENTRY && !VN_IS_DOOMED(vn))
583 cache_enter(vn, *vpp, cnp);
584 PFS_RETURN (0);
585 failed:
586 if (cnp->cn_flags & ISDOTDOT) {
587 vfs_unbusy(mp);
588 vn_lock(vn, LK_EXCLUSIVE | LK_RETRY);
589 *vpp = NULL;
590 }
591 PFS_RETURN(error);
592 }
593
594 /*
595 * Open a file or directory.
596 */
597 static int
pfs_open(struct vop_open_args * va)598 pfs_open(struct vop_open_args *va)
599 {
600 struct vnode *vn = va->a_vp;
601 struct pfs_vdata *pvd = vn->v_data;
602 struct pfs_node *pn = pvd->pvd_pn;
603 int mode = va->a_mode;
604
605 PFS_TRACE(("%s (mode 0x%x)", pn->pn_name, mode));
606 pfs_assert_not_owned(pn);
607
608 /* check if the requested mode is permitted */
609 if (((mode & FREAD) && !(mode & PFS_RD)) ||
610 ((mode & FWRITE) && !(mode & PFS_WR)))
611 PFS_RETURN (EPERM);
612
613 /* we don't support locking */
614 if ((mode & O_SHLOCK) || (mode & O_EXLOCK))
615 PFS_RETURN (EOPNOTSUPP);
616
617 PFS_RETURN (0);
618 }
619
620 struct sbuf_seek_helper {
621 off_t skip_bytes;
622 struct uio *uio;
623 };
624
625 static int
pfs_sbuf_uio_drain(void * arg,const char * data,int len)626 pfs_sbuf_uio_drain(void *arg, const char *data, int len)
627 {
628 struct sbuf_seek_helper *ssh;
629 struct uio *uio;
630 int error, skipped;
631
632 ssh = arg;
633 uio = ssh->uio;
634 skipped = 0;
635
636 /* Need to discard first uio_offset bytes. */
637 if (ssh->skip_bytes > 0) {
638 if (ssh->skip_bytes >= len) {
639 ssh->skip_bytes -= len;
640 return (len);
641 }
642
643 data += ssh->skip_bytes;
644 len -= ssh->skip_bytes;
645 skipped = ssh->skip_bytes;
646 ssh->skip_bytes = 0;
647 }
648
649 error = uiomove(__DECONST(void *, data), len, uio);
650 if (error != 0)
651 return (-error);
652
653 /*
654 * The fill function has more to emit, but the reader is finished.
655 * This is similar to the truncated read case for non-draining PFS
656 * sbufs, and should be handled appropriately in fill-routines.
657 */
658 if (uio->uio_resid == 0)
659 return (-ENOBUFS);
660
661 return (skipped + len);
662 }
663
664 /*
665 * Read from a file
666 */
667 static int
pfs_read(struct vop_read_args * va)668 pfs_read(struct vop_read_args *va)
669 {
670 struct vnode *vn = va->a_vp;
671 struct pfs_vdata *pvd = vn->v_data;
672 struct pfs_node *pn = pvd->pvd_pn;
673 struct uio *uio = va->a_uio;
674 struct proc *proc;
675 struct sbuf *sb = NULL;
676 int error, locked;
677 off_t buflen, buflim;
678 struct sbuf_seek_helper ssh;
679
680 PFS_TRACE(("%s", pn->pn_name));
681 pfs_assert_not_owned(pn);
682
683 if (vn->v_type != VREG)
684 PFS_RETURN (EINVAL);
685 KASSERT_PN_IS_FILE(pn);
686
687 if (!(pn->pn_flags & PFS_RD))
688 PFS_RETURN (EBADF);
689
690 if (pn->pn_fill == NULL)
691 PFS_RETURN (EIO);
692
693 /*
694 * This is necessary because either process' privileges may
695 * have changed since the open() call.
696 */
697 if (!pfs_visible(curthread, pn, pvd->pvd_pid, &proc))
698 PFS_RETURN (EIO);
699 if (proc != NULL) {
700 _PHOLD(proc);
701 PROC_UNLOCK(proc);
702 }
703
704 vhold(vn);
705 locked = VOP_ISLOCKED(vn);
706 VOP_UNLOCK(vn);
707
708 if (pn->pn_flags & PFS_RAWRD) {
709 PFS_TRACE(("%zd resid", uio->uio_resid));
710 error = pn_fill(curthread, proc, pn, NULL, uio);
711 PFS_TRACE(("%zd resid", uio->uio_resid));
712 goto ret;
713 }
714
715 if (uio->uio_resid < 0 || uio->uio_offset < 0 ||
716 uio->uio_resid > OFF_MAX - uio->uio_offset) {
717 error = EINVAL;
718 goto ret;
719 }
720 buflen = uio->uio_offset + uio->uio_resid + 1;
721 if (pn->pn_flags & PFS_AUTODRAIN)
722 /*
723 * We can use a smaller buffer if we can stream output to the
724 * consumer.
725 */
726 buflim = PAGE_SIZE;
727 else
728 buflim = PFS_MAXBUFSIZ;
729 if (buflen > buflim)
730 buflen = buflim;
731
732 sb = sbuf_new(sb, NULL, buflen, 0);
733 if (sb == NULL) {
734 error = EIO;
735 goto ret;
736 }
737
738 if (pn->pn_flags & PFS_AUTODRAIN) {
739 ssh.skip_bytes = uio->uio_offset;
740 ssh.uio = uio;
741 sbuf_set_drain(sb, pfs_sbuf_uio_drain, &ssh);
742 }
743
744 error = pn_fill(curthread, proc, pn, sb, uio);
745
746 if (error) {
747 sbuf_delete(sb);
748 goto ret;
749 }
750
751 /*
752 * XXX: If the buffer overflowed, sbuf_len() will not return
753 * the data length. Then just use the full length because an
754 * overflowed sbuf must be full.
755 */
756 error = sbuf_finish(sb);
757 if ((pn->pn_flags & PFS_AUTODRAIN)) {
758 /*
759 * ENOBUFS just indicates early termination of the fill
760 * function as the caller's buffer was already filled. Squash
761 * to zero.
762 */
763 if (uio->uio_resid == 0 && error == ENOBUFS)
764 error = 0;
765 } else {
766 if (error == 0)
767 buflen = sbuf_len(sb);
768 else
769 /* The trailing byte is not valid. */
770 buflen--;
771 error = uiomove_frombuf(sbuf_data(sb), buflen, uio);
772 }
773 sbuf_delete(sb);
774 ret:
775 vn_lock(vn, locked | LK_RETRY);
776 vdrop(vn);
777 if (proc != NULL)
778 PRELE(proc);
779 PFS_RETURN (error);
780 }
781
782 /*
783 * Iterate through directory entries
784 */
785 static int
pfs_iterate(struct thread * td,struct proc * proc,struct pfs_node * pd,struct pfs_node ** pn,struct proc ** p)786 pfs_iterate(struct thread *td, struct proc *proc, struct pfs_node *pd,
787 struct pfs_node **pn, struct proc **p)
788 {
789 int visible;
790
791 sx_assert(&allproc_lock, SX_SLOCKED);
792 pfs_assert_owned(pd);
793 again:
794 if (*pn == NULL) {
795 /* first node */
796 *pn = pd->pn_nodes;
797 } else if ((*pn)->pn_type != pfstype_procdir) {
798 /* next node */
799 *pn = (*pn)->pn_next;
800 }
801 if (*pn != NULL && (*pn)->pn_type == pfstype_procdir) {
802 /* next process */
803 if (*p == NULL)
804 *p = LIST_FIRST(&allproc);
805 else
806 *p = LIST_NEXT(*p, p_list);
807 /* out of processes: next node */
808 if (*p == NULL)
809 *pn = (*pn)->pn_next;
810 else
811 PROC_LOCK(*p);
812 }
813
814 if ((*pn) == NULL)
815 return (-1);
816
817 if (*p != NULL) {
818 visible = pfs_visible_proc(td, *pn, *p);
819 PROC_UNLOCK(*p);
820 } else if (proc != NULL) {
821 visible = pfs_visible_proc(td, *pn, proc);
822 } else {
823 visible = pn_vis(td, NULL, *pn);
824 }
825 if (!visible)
826 goto again;
827
828 return (0);
829 }
830
831 /* Directory entry list */
832 struct pfsentry {
833 STAILQ_ENTRY(pfsentry) link;
834 struct dirent entry;
835 };
836 STAILQ_HEAD(pfsdirentlist, pfsentry);
837
838 /*
839 * Return directory entries.
840 */
841 static int
pfs_readdir(struct vop_readdir_args * va)842 pfs_readdir(struct vop_readdir_args *va)
843 {
844 struct vnode *vn = va->a_vp;
845 struct pfs_vdata *pvd = vn->v_data;
846 struct pfs_node *pd = pvd->pvd_pn;
847 pid_t pid = pvd->pvd_pid;
848 struct proc *p, *proc;
849 struct pfs_node *pn;
850 struct uio *uio;
851 struct pfsentry *pfsent, *pfsent2;
852 struct pfsdirentlist lst;
853 off_t offset;
854 int error, i, resid;
855
856 STAILQ_INIT(&lst);
857 error = 0;
858 KASSERT(pd->pn_info == vn->v_mount->mnt_data,
859 ("%s(): pn_info does not match mountpoint", __func__));
860 PFS_TRACE(("%s pid %lu", pd->pn_name, (unsigned long)pid));
861 pfs_assert_not_owned(pd);
862
863 if (vn->v_type != VDIR)
864 PFS_RETURN (ENOTDIR);
865 KASSERT_PN_IS_DIR(pd);
866 uio = va->a_uio;
867
868 /* only allow reading entire entries */
869 offset = uio->uio_offset;
870 resid = uio->uio_resid;
871 if (offset < 0 || offset % PFS_DELEN != 0 ||
872 (resid && resid < PFS_DELEN))
873 PFS_RETURN (EINVAL);
874 if (resid == 0)
875 PFS_RETURN (0);
876
877 proc = NULL;
878 if (pid != NO_PID && !pfs_lookup_proc(pid, &proc))
879 PFS_RETURN (ENOENT);
880
881 sx_slock(&allproc_lock);
882 pfs_lock(pd);
883
884 KASSERT(pid == NO_PID || proc != NULL,
885 ("%s(): no process for pid %lu", __func__, (unsigned long)pid));
886
887 if (pid != NO_PID) {
888 PROC_LOCK(proc);
889
890 /* check if the directory is visible to the caller */
891 if (!pfs_visible_proc(curthread, pd, proc)) {
892 _PRELE(proc);
893 PROC_UNLOCK(proc);
894 pfs_unlock(pd);
895 sx_sunlock(&allproc_lock);
896 PFS_RETURN (ENOENT);
897 }
898 }
899
900 /* skip unwanted entries */
901 for (pn = NULL, p = NULL; offset > 0; offset -= PFS_DELEN) {
902 if (pfs_iterate(curthread, proc, pd, &pn, &p) == -1) {
903 /* nothing left... */
904 if (proc != NULL) {
905 _PRELE(proc);
906 PROC_UNLOCK(proc);
907 }
908 pfs_unlock(pd);
909 sx_sunlock(&allproc_lock);
910 PFS_RETURN (0);
911 }
912 }
913
914 /* fill in entries */
915 while (pfs_iterate(curthread, proc, pd, &pn, &p) != -1 &&
916 resid >= PFS_DELEN) {
917 if ((pfsent = malloc(sizeof(struct pfsentry), M_IOV,
918 M_NOWAIT | M_ZERO)) == NULL) {
919 error = ENOMEM;
920 break;
921 }
922 pfsent->entry.d_reclen = PFS_DELEN;
923 pfsent->entry.d_fileno = pn_fileno(pn, pid);
924 /* PFS_DELEN was picked to fit PFS_NAMLEN */
925 for (i = 0; i < PFS_NAMELEN - 1 && pn->pn_name[i] != '\0'; ++i)
926 pfsent->entry.d_name[i] = pn->pn_name[i];
927 pfsent->entry.d_namlen = i;
928 /* NOTE: d_off is the offset of the *next* entry. */
929 pfsent->entry.d_off = offset + PFS_DELEN;
930 switch (pn->pn_type) {
931 case pfstype_procdir:
932 KASSERT(p != NULL,
933 ("reached procdir node with p == NULL"));
934 pfsent->entry.d_namlen = snprintf(pfsent->entry.d_name,
935 PFS_NAMELEN, "%d", p->p_pid);
936 /* fall through */
937 case pfstype_root:
938 case pfstype_dir:
939 case pfstype_this:
940 case pfstype_parent:
941 pfsent->entry.d_type = DT_DIR;
942 break;
943 case pfstype_file:
944 pfsent->entry.d_type = DT_REG;
945 break;
946 case pfstype_symlink:
947 pfsent->entry.d_type = DT_LNK;
948 break;
949 default:
950 panic("%s has unexpected node type: %d", pn->pn_name, pn->pn_type);
951 }
952 PFS_TRACE(("%s", pfsent->entry.d_name));
953 dirent_terminate(&pfsent->entry);
954 STAILQ_INSERT_TAIL(&lst, pfsent, link);
955 offset += PFS_DELEN;
956 resid -= PFS_DELEN;
957 }
958 if (proc != NULL) {
959 _PRELE(proc);
960 PROC_UNLOCK(proc);
961 }
962 pfs_unlock(pd);
963 sx_sunlock(&allproc_lock);
964 i = 0;
965 STAILQ_FOREACH_SAFE(pfsent, &lst, link, pfsent2) {
966 if (error == 0)
967 error = uiomove(&pfsent->entry, PFS_DELEN, uio);
968 free(pfsent, M_IOV);
969 i++;
970 }
971 PFS_TRACE(("%ju bytes", (uintmax_t)(i * PFS_DELEN)));
972 PFS_RETURN (error);
973 }
974
975 /*
976 * Read a symbolic link
977 */
978 static int
pfs_readlink(struct vop_readlink_args * va)979 pfs_readlink(struct vop_readlink_args *va)
980 {
981 struct vnode *vn = va->a_vp;
982 struct pfs_vdata *pvd = vn->v_data;
983 struct pfs_node *pn = pvd->pvd_pn;
984 struct uio *uio = va->a_uio;
985 struct proc *proc = NULL;
986 char buf[PATH_MAX];
987 struct sbuf sb;
988 int error, locked;
989
990 PFS_TRACE(("%s", pn->pn_name));
991 pfs_assert_not_owned(pn);
992
993 if (vn->v_type != VLNK)
994 PFS_RETURN (EINVAL);
995 KASSERT_PN_IS_LINK(pn);
996
997 if (pn->pn_fill == NULL)
998 PFS_RETURN (EIO);
999
1000 if (pvd->pvd_pid != NO_PID) {
1001 if ((proc = pfind(pvd->pvd_pid)) == NULL)
1002 PFS_RETURN (EIO);
1003 if (proc->p_flag & P_WEXIT) {
1004 PROC_UNLOCK(proc);
1005 PFS_RETURN (EIO);
1006 }
1007 _PHOLD(proc);
1008 PROC_UNLOCK(proc);
1009 }
1010 vhold(vn);
1011 locked = VOP_ISLOCKED(vn);
1012 VOP_UNLOCK(vn);
1013
1014 /* sbuf_new() can't fail with a static buffer */
1015 sbuf_new(&sb, buf, sizeof buf, 0);
1016
1017 error = pn_fill(curthread, proc, pn, &sb, NULL);
1018
1019 if (proc != NULL)
1020 PRELE(proc);
1021 vn_lock(vn, locked | LK_RETRY);
1022 vdrop(vn);
1023
1024 if (error) {
1025 sbuf_delete(&sb);
1026 PFS_RETURN (error);
1027 }
1028
1029 if (sbuf_finish(&sb) != 0) {
1030 sbuf_delete(&sb);
1031 PFS_RETURN (ENAMETOOLONG);
1032 }
1033
1034 error = uiomove_frombuf(sbuf_data(&sb), sbuf_len(&sb), uio);
1035 sbuf_delete(&sb);
1036 PFS_RETURN (error);
1037 }
1038
1039 /*
1040 * Reclaim a vnode
1041 */
1042 static int
pfs_reclaim(struct vop_reclaim_args * va)1043 pfs_reclaim(struct vop_reclaim_args *va)
1044 {
1045 struct vnode *vn = va->a_vp;
1046 struct pfs_vdata *pvd = vn->v_data;
1047 struct pfs_node *pn = pvd->pvd_pn;
1048
1049 PFS_TRACE(("%s", pn->pn_name));
1050 pfs_assert_not_owned(pn);
1051
1052 return (pfs_vncache_free(va->a_vp));
1053 }
1054
1055 /*
1056 * Set attributes
1057 */
1058 static int
pfs_setattr(struct vop_setattr_args * va)1059 pfs_setattr(struct vop_setattr_args *va)
1060 {
1061 struct vnode *vn = va->a_vp;
1062 struct pfs_vdata *pvd = vn->v_data;
1063 struct pfs_node *pn = pvd->pvd_pn;
1064
1065 PFS_TRACE(("%s", pn->pn_name));
1066 pfs_assert_not_owned(pn);
1067
1068 /* Silently ignore unchangeable attributes. */
1069 PFS_RETURN (0);
1070 }
1071
1072 /*
1073 * Write to a file
1074 */
1075 static int
pfs_write(struct vop_write_args * va)1076 pfs_write(struct vop_write_args *va)
1077 {
1078 struct vnode *vn = va->a_vp;
1079 struct pfs_vdata *pvd = vn->v_data;
1080 struct pfs_node *pn = pvd->pvd_pn;
1081 struct uio *uio = va->a_uio;
1082 struct proc *proc;
1083 struct sbuf sb;
1084 int error;
1085
1086 PFS_TRACE(("%s", pn->pn_name));
1087 pfs_assert_not_owned(pn);
1088
1089 if (vn->v_type != VREG)
1090 PFS_RETURN (EINVAL);
1091 KASSERT_PN_IS_FILE(pn);
1092
1093 if (!(pn->pn_flags & PFS_WR))
1094 PFS_RETURN (EBADF);
1095
1096 if (pn->pn_fill == NULL)
1097 PFS_RETURN (EIO);
1098
1099 if (uio->uio_resid > PFS_MAXBUFSIZ)
1100 PFS_RETURN (EIO);
1101
1102 /*
1103 * This is necessary because either process' privileges may
1104 * have changed since the open() call.
1105 */
1106 if (!pfs_visible(curthread, pn, pvd->pvd_pid, &proc))
1107 PFS_RETURN (EIO);
1108 if (proc != NULL) {
1109 _PHOLD(proc);
1110 PROC_UNLOCK(proc);
1111 }
1112
1113 if (pn->pn_flags & PFS_RAWWR) {
1114 error = pn_fill(curthread, proc, pn, NULL, uio);
1115 if (proc != NULL)
1116 PRELE(proc);
1117 PFS_RETURN (error);
1118 }
1119
1120 sbuf_uionew(&sb, uio, &error);
1121 if (error) {
1122 if (proc != NULL)
1123 PRELE(proc);
1124 PFS_RETURN (error);
1125 }
1126
1127 error = pn_fill(curthread, proc, pn, &sb, uio);
1128
1129 sbuf_delete(&sb);
1130 if (proc != NULL)
1131 PRELE(proc);
1132 PFS_RETURN (error);
1133 }
1134
1135 /*
1136 * Vnode operations
1137 */
1138 struct vop_vector pfs_vnodeops = {
1139 .vop_default = &default_vnodeops,
1140
1141 .vop_access = pfs_access,
1142 .vop_cachedlookup = pfs_lookup,
1143 .vop_close = pfs_close,
1144 .vop_create = VOP_EOPNOTSUPP,
1145 .vop_getattr = pfs_getattr,
1146 .vop_getextattr = pfs_getextattr,
1147 .vop_ioctl = pfs_ioctl,
1148 .vop_link = VOP_EOPNOTSUPP,
1149 .vop_lookup = vfs_cache_lookup,
1150 .vop_mkdir = VOP_EOPNOTSUPP,
1151 .vop_mknod = VOP_EOPNOTSUPP,
1152 .vop_open = pfs_open,
1153 .vop_read = pfs_read,
1154 .vop_readdir = pfs_readdir,
1155 .vop_readlink = pfs_readlink,
1156 .vop_reclaim = pfs_reclaim,
1157 .vop_remove = VOP_EOPNOTSUPP,
1158 .vop_rename = VOP_EOPNOTSUPP,
1159 .vop_rmdir = VOP_EOPNOTSUPP,
1160 .vop_setattr = pfs_setattr,
1161 .vop_symlink = VOP_EOPNOTSUPP,
1162 .vop_vptocnp = pfs_vptocnp,
1163 .vop_write = pfs_write,
1164 .vop_add_writecount = vop_stdadd_writecount_nomsync,
1165 /* XXX I've probably forgotten a few that need VOP_EOPNOTSUPP */
1166 };
1167 VFS_VOP_VECTOR_REGISTER(pfs_vnodeops);
1168