xref: /netbsd-src/sys/miscfs/procfs/procfs_vnops.c (revision ce0bb6e8d2e560ecacbe865a848624f94498063b)
1 /*	$NetBSD: procfs_vnops.c,v 1.33 1995/04/15 01:56:51 cgd Exp $	*/
2 
3 /*
4  * Copyright (c) 1993 Jan-Simon Pendry
5  * Copyright (c) 1993
6  *	The Regents of the University of California.  All rights reserved.
7  *
8  * This code is derived from software contributed to Berkeley by
9  * Jan-Simon Pendry.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 3. All advertising materials mentioning features or use of this software
20  *    must display the following acknowledgement:
21  *	This product includes software developed by the University of
22  *	California, Berkeley and its contributors.
23  * 4. Neither the name of the University nor the names of its contributors
24  *    may be used to endorse or promote products derived from this software
25  *    without specific prior written permission.
26  *
27  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37  * SUCH DAMAGE.
38  *
39  *	@(#)procfs_vnops.c	8.8 (Berkeley) 6/15/94
40  */
41 
42 /*
43  * procfs vnode interface
44  */
45 
46 #include <sys/param.h>
47 #include <sys/systm.h>
48 #include <sys/time.h>
49 #include <sys/kernel.h>
50 #include <sys/file.h>
51 #include <sys/proc.h>
52 #include <sys/vnode.h>
53 #include <sys/namei.h>
54 #include <sys/malloc.h>
55 #include <sys/dirent.h>
56 #include <sys/resourcevar.h>
57 #include <sys/ptrace.h>
58 #include <vm/vm.h>	/* for PAGE_SIZE */
59 #include <machine/reg.h>
60 #include <miscfs/procfs/procfs.h>
61 
62 /*
63  * Vnode Operations.
64  *
65  */
66 
67 /*
68  * This is a list of the valid names in the
69  * process-specific sub-directories.  It is
70  * used in procfs_lookup and procfs_readdir
71  */
72 struct proc_target {
73 	u_char	pt_type;
74 	u_char	pt_namlen;
75 	char	*pt_name;
76 	pfstype	pt_pfstype;
77 	int	(*pt_valid) __P((struct proc *p));
78 } proc_targets[] = {
79 #define N(s) sizeof(s)-1, s
80 	/*	  name		type		validp */
81 	{ DT_DIR, N("."),	Pproc,		NULL },
82 	{ DT_DIR, N(".."),	Proot,		NULL },
83 	{ DT_REG, N("file"),	Pfile,		procfs_validfile },
84 	{ DT_REG, N("mem"),	Pmem,		NULL },
85 	{ DT_REG, N("regs"),	Pregs,		procfs_validregs },
86 	{ DT_REG, N("fpregs"),	Pfpregs,	procfs_validfpregs },
87 	{ DT_REG, N("ctl"),	Pctl,		NULL },
88 	{ DT_REG, N("status"),	Pstatus,	NULL },
89 	{ DT_REG, N("note"),	Pnote,		NULL },
90 	{ DT_REG, N("notepg"),	Pnotepg,	NULL },
91 #undef N
92 };
93 static int nproc_targets = sizeof(proc_targets) / sizeof(proc_targets[0]);
94 
95 static pid_t atopid __P((const char *, u_int));
96 
97 /*
98  * set things up for doing i/o on
99  * the pfsnode (vp).  (vp) is locked
100  * on entry, and should be left locked
101  * on exit.
102  *
103  * for procfs we don't need to do anything
104  * in particular for i/o.  all that is done
105  * is to support exclusive open on process
106  * memory images.
107  */
108 procfs_open(ap)
109 	struct vop_open_args /* {
110 		struct vnode *a_vp;
111 		int  a_mode;
112 		struct ucred *a_cred;
113 		struct proc *a_p;
114 	} */ *ap;
115 {
116 	struct pfsnode *pfs = VTOPFS(ap->a_vp);
117 
118 	switch (pfs->pfs_type) {
119 	case Pmem:
120 		if (PFIND(pfs->pfs_pid) == 0)
121 			return (ENOENT);	/* was ESRCH, jsp */
122 
123 		if ((pfs->pfs_flags & FWRITE) && (ap->a_mode & O_EXCL) ||
124 		    (pfs->pfs_flags & O_EXCL) && (ap->a_mode & FWRITE))
125 			return (EBUSY);
126 
127 		if (ap->a_mode & FWRITE)
128 			pfs->pfs_flags = ap->a_mode & (FWRITE|O_EXCL);
129 
130 		return (0);
131 
132 	default:
133 		break;
134 	}
135 
136 	return (0);
137 }
138 
139 /*
140  * close the pfsnode (vp) after doing i/o.
141  * (vp) is not locked on entry or exit.
142  *
143  * nothing to do for procfs other than undo
144  * any exclusive open flag (see _open above).
145  */
146 procfs_close(ap)
147 	struct vop_close_args /* {
148 		struct vnode *a_vp;
149 		int  a_fflag;
150 		struct ucred *a_cred;
151 		struct proc *a_p;
152 	} */ *ap;
153 {
154 	struct pfsnode *pfs = VTOPFS(ap->a_vp);
155 
156 	switch (pfs->pfs_type) {
157 	case Pmem:
158 		if ((ap->a_fflag & FWRITE) && (pfs->pfs_flags & O_EXCL))
159 			pfs->pfs_flags &= ~(FWRITE|O_EXCL);
160 		break;
161 	}
162 
163 	return (0);
164 }
165 
166 /*
167  * do an ioctl operation on pfsnode (vp).
168  * (vp) is not locked on entry or exit.
169  */
170 procfs_ioctl(ap)
171 	struct vop_ioctl_args /* {
172 		struct vnode *a_vp;
173 		u_long a_command;
174 		caddr_t a_data;
175 		int a_fflag;
176 		struct ucred *a_cred;
177 		struct proc *a_p;
178 	} */ *ap;
179 {
180 
181 	return (ENOTTY);
182 }
183 
184 /*
185  * do block mapping for pfsnode (vp).
186  * since we don't use the buffer cache
187  * for procfs this function should never
188  * be called.  in any case, it's not clear
189  * what part of the kernel ever makes use
190  * of this function.  for sanity, this is the
191  * usual no-op bmap, although returning
192  * (EIO) would be a reasonable alternative.
193  */
194 procfs_bmap(ap)
195 	struct vop_bmap_args /* {
196 		struct vnode *a_vp;
197 		daddr_t  a_bn;
198 		struct vnode **a_vpp;
199 		daddr_t *a_bnp;
200 	} */ *ap;
201 {
202 
203 	if (ap->a_vpp != NULL)
204 		*ap->a_vpp = ap->a_vp;
205 	if (ap->a_bnp != NULL)
206 		*ap->a_bnp = ap->a_bn;
207 	return (0);
208 }
209 
210 /*
211  * _inactive is called when the pfsnode
212  * is vrele'd and the reference count goes
213  * to zero.  (vp) will be on the vnode free
214  * list, so to get it back vget() must be
215  * used.
216  *
217  * for procfs, check if the process is still
218  * alive and if it isn't then just throw away
219  * the vnode by calling vgone().  this may
220  * be overkill and a waste of time since the
221  * chances are that the process will still be
222  * there and PFIND is not free.
223  *
224  * (vp) is not locked on entry or exit.
225  */
226 procfs_inactive(ap)
227 	struct vop_inactive_args /* {
228 		struct vnode *a_vp;
229 	} */ *ap;
230 {
231 	struct pfsnode *pfs = VTOPFS(ap->a_vp);
232 
233 	if (PFIND(pfs->pfs_pid) == 0)
234 		vgone(ap->a_vp);
235 
236 	return (0);
237 }
238 
239 /*
240  * _reclaim is called when getnewvnode()
241  * wants to make use of an entry on the vnode
242  * free list.  at this time the filesystem needs
243  * to free any private data and remove the node
244  * from any private lists.
245  */
246 procfs_reclaim(ap)
247 	struct vop_reclaim_args /* {
248 		struct vnode *a_vp;
249 	} */ *ap;
250 {
251 
252 	return (procfs_freevp(ap->a_vp));
253 }
254 
255 /*
256  * Return POSIX pathconf information applicable to special devices.
257  */
258 procfs_pathconf(ap)
259 	struct vop_pathconf_args /* {
260 		struct vnode *a_vp;
261 		int a_name;
262 		register_t *a_retval;
263 	} */ *ap;
264 {
265 
266 	switch (ap->a_name) {
267 	case _PC_LINK_MAX:
268 		*ap->a_retval = LINK_MAX;
269 		return (0);
270 	case _PC_MAX_CANON:
271 		*ap->a_retval = MAX_CANON;
272 		return (0);
273 	case _PC_MAX_INPUT:
274 		*ap->a_retval = MAX_INPUT;
275 		return (0);
276 	case _PC_PIPE_BUF:
277 		*ap->a_retval = PIPE_BUF;
278 		return (0);
279 	case _PC_CHOWN_RESTRICTED:
280 		*ap->a_retval = 1;
281 		return (0);
282 	case _PC_VDISABLE:
283 		*ap->a_retval = _POSIX_VDISABLE;
284 		return (0);
285 	default:
286 		return (EINVAL);
287 	}
288 	/* NOTREACHED */
289 }
290 
291 /*
292  * _print is used for debugging.
293  * just print a readable description
294  * of (vp).
295  */
296 procfs_print(ap)
297 	struct vop_print_args /* {
298 		struct vnode *a_vp;
299 	} */ *ap;
300 {
301 	struct pfsnode *pfs = VTOPFS(ap->a_vp);
302 
303 	printf("tag VT_PROCFS, type %s, pid %d, mode %x, flags %x\n",
304 	    pfs->pfs_type, pfs->pfs_pid, pfs->pfs_mode, pfs->pfs_flags);
305 }
306 
307 /*
308  * _abortop is called when operations such as
309  * rename and create fail.  this entry is responsible
310  * for undoing any side-effects caused by the lookup.
311  * this will always include freeing the pathname buffer.
312  */
313 procfs_abortop(ap)
314 	struct vop_abortop_args /* {
315 		struct vnode *a_dvp;
316 		struct componentname *a_cnp;
317 	} */ *ap;
318 {
319 
320 	if ((ap->a_cnp->cn_flags & (HASBUF | SAVESTART)) == HASBUF)
321 		FREE(ap->a_cnp->cn_pnbuf, M_NAMEI);
322 	return (0);
323 }
324 
325 /*
326  * generic entry point for unsupported operations
327  */
328 procfs_badop()
329 {
330 
331 	return (EIO);
332 }
333 
334 /*
335  * Invent attributes for pfsnode (vp) and store
336  * them in (vap).
337  * Directories lengths are returned as zero since
338  * any real length would require the genuine size
339  * to be computed, and nothing cares anyway.
340  *
341  * this is relatively minimal for procfs.
342  */
343 procfs_getattr(ap)
344 	struct vop_getattr_args /* {
345 		struct vnode *a_vp;
346 		struct vattr *a_vap;
347 		struct ucred *a_cred;
348 		struct proc *a_p;
349 	} */ *ap;
350 {
351 	struct pfsnode *pfs = VTOPFS(ap->a_vp);
352 	struct vattr *vap = ap->a_vap;
353 	struct proc *procp;
354 	struct timeval tv;
355 	int error;
356 
357 	/* first check the process still exists */
358 	switch (pfs->pfs_type) {
359 	case Proot:
360 	case Pcurproc:
361 		procp = 0;
362 		break;
363 
364 	default:
365 		procp = PFIND(pfs->pfs_pid);
366 		if (procp == 0)
367 			return (ENOENT);
368 	}
369 
370 	error = 0;
371 
372 	/* start by zeroing out the attributes */
373 	VATTR_NULL(vap);
374 
375 	/* next do all the common fields */
376 	vap->va_type = ap->a_vp->v_type;
377 	vap->va_mode = pfs->pfs_mode;
378 	vap->va_fileid = pfs->pfs_fileno;
379 	vap->va_flags = 0;
380 	vap->va_blocksize = PAGE_SIZE;
381 	vap->va_bytes = vap->va_size = 0;
382 
383 	/*
384 	 * Make all times be current TOD.
385 	 * It would be possible to get the process start
386 	 * time from the p_stat structure, but there's
387 	 * no "file creation" time stamp anyway, and the
388 	 * p_stat structure is not addressible if u. gets
389 	 * swapped out for that process.
390 	 */
391 	microtime(&tv);
392 	TIMEVAL_TO_TIMESPEC(&tv, &vap->va_ctime);
393 	vap->va_atime = vap->va_mtime = vap->va_ctime;
394 
395 	/*
396 	 * If the process has exercised some setuid or setgid
397 	 * privilege, then rip away read/write permission so
398 	 * that only root can gain access.
399 	 */
400 	switch (pfs->pfs_type) {
401 	case Pmem:
402 	case Pregs:
403 	case Pfpregs:
404 		if (procp->p_flag & P_SUGID)
405 			vap->va_mode &= ~((VREAD|VWRITE)|
406 					  ((VREAD|VWRITE)>>3)|
407 					  ((VREAD|VWRITE)>>6));
408 	case Pctl:
409 	case Pstatus:
410 	case Pnote:
411 	case Pnotepg:
412 		vap->va_nlink = 1;
413 		vap->va_uid = procp->p_ucred->cr_uid;
414 		vap->va_gid = procp->p_ucred->cr_gid;
415 		break;
416 	}
417 
418 	/*
419 	 * now do the object specific fields
420 	 *
421 	 * The size could be set from struct reg, but it's hardly
422 	 * worth the trouble, and it puts some (potentially) machine
423 	 * dependent data into this machine-independent code.  If it
424 	 * becomes important then this function should break out into
425 	 * a per-file stat function in the corresponding .c file.
426 	 */
427 
428 	switch (pfs->pfs_type) {
429 	case Proot:
430 		/*
431 		 * Set nlink to 1 to tell fts(3) we don't actually know.
432 		 */
433 		vap->va_nlink = 1;
434 		vap->va_uid = 0;
435 		vap->va_gid = 0;
436 		vap->va_size = vap->va_bytes = DEV_BSIZE;
437 		break;
438 
439 	case Pcurproc: {
440 		char buf[16];		/* should be enough */
441 		vap->va_nlink = 1;
442 		vap->va_uid = 0;
443 		vap->va_gid = 0;
444 		vap->va_size = vap->va_bytes =
445 		    sprintf(buf, "%ld", (long)curproc->p_pid);
446 		break;
447 	}
448 
449 	case Pproc:
450 		vap->va_nlink = 2;
451 		vap->va_uid = procp->p_ucred->cr_uid;
452 		vap->va_gid = procp->p_ucred->cr_gid;
453 		vap->va_size = vap->va_bytes = DEV_BSIZE;
454 		break;
455 
456 	case Pfile:
457 		error = EOPNOTSUPP;
458 		break;
459 
460 	case Pmem:
461 		vap->va_bytes = vap->va_size =
462 			ctob(procp->p_vmspace->vm_tsize +
463 				    procp->p_vmspace->vm_dsize +
464 				    procp->p_vmspace->vm_ssize);
465 		break;
466 
467 #if defined(PT_GETREGS) || defined(PT_SETREGS)
468 	case Pregs:
469 		vap->va_bytes = vap->va_size = sizeof(struct reg);
470 		break;
471 #endif
472 
473 #if defined(PT_GETFPREGS) || defined(PT_SETFPREGS)
474 	case Pfpregs:
475 		vap->va_bytes = vap->va_size = sizeof(struct fpreg);
476 		break;
477 #endif
478 
479 	case Pctl:
480 	case Pstatus:
481 	case Pnote:
482 	case Pnotepg:
483 		break;
484 
485 	default:
486 		panic("procfs_getattr");
487 	}
488 
489 	return (error);
490 }
491 
492 procfs_setattr(ap)
493 	struct vop_setattr_args /* {
494 		struct vnode *a_vp;
495 		struct vattr *a_vap;
496 		struct ucred *a_cred;
497 		struct proc *a_p;
498 	} */ *ap;
499 {
500 	/*
501 	 * just fake out attribute setting
502 	 * it's not good to generate an error
503 	 * return, otherwise things like creat()
504 	 * will fail when they try to set the
505 	 * file length to 0.  worse, this means
506 	 * that echo $note > /proc/$pid/note will fail.
507 	 */
508 
509 	return (0);
510 }
511 
512 /*
513  * implement access checking.
514  *
515  * actually, the check for super-user is slightly
516  * broken since it will allow read access to write-only
517  * objects.  this doesn't cause any particular trouble
518  * but does mean that the i/o entry points need to check
519  * that the operation really does make sense.
520  */
521 procfs_access(ap)
522 	struct vop_access_args /* {
523 		struct vnode *a_vp;
524 		int a_mode;
525 		struct ucred *a_cred;
526 		struct proc *a_p;
527 	} */ *ap;
528 {
529 	struct vattr va;
530 	int error;
531 
532 	if (error = VOP_GETATTR(ap->a_vp, &va, ap->a_cred, ap->a_p))
533 		return (error);
534 
535 	return (vaccess(va.va_mode, va.va_uid, va.va_gid, ap->a_mode,
536 	    ap->a_cred));
537 }
538 
539 /*
540  * lookup.  this is incredibly complicated in the
541  * general case, however for most pseudo-filesystems
542  * very little needs to be done.
543  *
544  * unless you want to get a migraine, just make sure your
545  * filesystem doesn't do any locking of its own.  otherwise
546  * read and inwardly digest ufs_lookup().
547  */
548 procfs_lookup(ap)
549 	struct vop_lookup_args /* {
550 		struct vnode * a_dvp;
551 		struct vnode ** a_vpp;
552 		struct componentname * a_cnp;
553 	} */ *ap;
554 {
555 	struct componentname *cnp = ap->a_cnp;
556 	struct vnode **vpp = ap->a_vpp;
557 	struct vnode *dvp = ap->a_dvp;
558 	char *pname = cnp->cn_nameptr;
559 	struct proc_target *pt;
560 	struct vnode *fvp;
561 	pid_t pid;
562 	struct pfsnode *pfs;
563 	struct proc *p;
564 	int i;
565 
566 	*vpp = NULL;
567 
568 	if (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)
569 		return (EROFS);
570 
571 	if (cnp->cn_namelen == 1 && *pname == '.') {
572 		*vpp = dvp;
573 		VREF(dvp);
574 		/*VOP_LOCK(dvp);*/
575 		return (0);
576 	}
577 
578 	pfs = VTOPFS(dvp);
579 	switch (pfs->pfs_type) {
580 	case Proot:
581 		if (cnp->cn_flags & ISDOTDOT)
582 			return (EIO);
583 
584 		if (CNEQ(cnp, "curproc", 7))
585 			return (procfs_allocvp(dvp->v_mount, vpp, 0, Pcurproc));
586 
587 		pid = atopid(pname, cnp->cn_namelen);
588 		if (pid == NO_PID)
589 			break;
590 
591 		p = PFIND(pid);
592 		if (p == 0)
593 			break;
594 
595 		return (procfs_allocvp(dvp->v_mount, vpp, pid, Pproc));
596 
597 	case Pproc:
598 		if (cnp->cn_flags & ISDOTDOT)
599 			return (procfs_root(dvp->v_mount, vpp));
600 
601 		p = PFIND(pfs->pfs_pid);
602 		if (p == 0)
603 			break;
604 
605 		for (pt = proc_targets, i = 0; i < nproc_targets; pt++, i++) {
606 			if (cnp->cn_namelen == pt->pt_namlen &&
607 			    bcmp(pt->pt_name, pname, cnp->cn_namelen) == 0 &&
608 			    (pt->pt_valid == NULL || (*pt->pt_valid)(p)))
609 				goto found;
610 		}
611 		break;
612 
613 	found:
614 		if (pt->pt_pfstype == Pfile) {
615 			fvp = procfs_findtextvp(p);
616 			/* We already checked that it exists. */
617 			VREF(fvp);
618 			VOP_LOCK(fvp);
619 			*vpp = fvp;
620 			return (0);
621 		}
622 
623 		return (procfs_allocvp(dvp->v_mount, vpp, pfs->pfs_pid,
624 		    pt->pt_pfstype));
625 
626 	default:
627 		return (ENOTDIR);
628 	}
629 
630 	return (cnp->cn_nameiop == LOOKUP ? ENOENT : EROFS);
631 }
632 
633 int
634 procfs_validfile(p)
635 	struct proc *p;
636 {
637 
638 	return (procfs_findtextvp(p) != NULLVP);
639 }
640 
641 /*
642  * readdir returns directory entries from pfsnode (vp).
643  *
644  * the strategy here with procfs is to generate a single
645  * directory entry at a time (struct pfsdent) and then
646  * copy that out to userland using uiomove.  a more efficent
647  * though more complex implementation, would try to minimize
648  * the number of calls to uiomove().  for procfs, this is
649  * hardly worth the added code complexity.
650  *
651  * this should just be done through read()
652  */
653 procfs_readdir(ap)
654 	struct vop_readdir_args /* {
655 		struct vnode *a_vp;
656 		struct uio *a_uio;
657 		struct ucred *a_cred;
658 		int *a_eofflag;
659 		u_long *a_cookies;
660 		int a_ncookies;
661 	} */ *ap;
662 {
663 	struct uio *uio = ap->a_uio;
664 	struct pfsdent d;
665 	struct pfsdent *dp = &d;
666 	struct pfsnode *pfs;
667 	int error;
668 	int count;
669 	int i;
670 
671 	/*
672 	 * We don't allow exporting procfs mounts, and currently local
673 	 * requests do not need cookies.
674 	 */
675 	if (ap->a_ncookies)
676 		panic("procfs_readdir: not hungry");
677 
678 	pfs = VTOPFS(ap->a_vp);
679 
680 	if (uio->uio_resid < UIO_MX)
681 		return (EINVAL);
682 	if (uio->uio_offset & (UIO_MX-1))
683 		return (EINVAL);
684 	if (uio->uio_offset < 0)
685 		return (EINVAL);
686 
687 	error = 0;
688 	count = 0;
689 	i = uio->uio_offset / UIO_MX;
690 
691 	switch (pfs->pfs_type) {
692 	/*
693 	 * this is for the process-specific sub-directories.
694 	 * all that is needed to is copy out all the entries
695 	 * from the procent[] table (top of this file).
696 	 */
697 	case Pproc: {
698 		struct proc *p;
699 		struct proc_target *pt;
700 
701 		p = PFIND(pfs->pfs_pid);
702 		if (p == NULL)
703 			break;
704 
705 		for (pt = &proc_targets[i];
706 		     uio->uio_resid >= UIO_MX && i < nproc_targets; pt++, i++) {
707 			if (pt->pt_valid && (*pt->pt_valid)(p) == 0)
708 				continue;
709 
710 			dp->d_reclen = UIO_MX;
711 			dp->d_fileno = PROCFS_FILENO(pfs->pfs_pid, pt->pt_pfstype);
712 			dp->d_namlen = pt->pt_namlen;
713 			bcopy(pt->pt_name, dp->d_name, pt->pt_namlen + 1);
714 			dp->d_type = pt->pt_type;
715 
716 			if (error = uiomove((caddr_t)dp, UIO_MX, uio))
717 				break;
718 		}
719 
720 	    	break;
721 	    }
722 
723 	/*
724 	 * this is for the root of the procfs filesystem
725 	 * what is needed is a special entry for "curproc"
726 	 * followed by an entry for each process on allproc
727 #ifdef PROCFS_ZOMBIE
728 	 * and zombproc.
729 #endif
730 	 */
731 
732 	case Proot: {
733 #ifdef PROCFS_ZOMBIE
734 		int doingzomb = 0;
735 #endif
736 		int pcnt = 0;
737 		volatile struct proc *p = allproc.lh_first;
738 
739 	again:
740 		for (; p && uio->uio_resid >= UIO_MX; i++, pcnt++) {
741 			bzero((char *) dp, UIO_MX);
742 			dp->d_reclen = UIO_MX;
743 
744 			switch (i) {
745 			case 0:		/* `.' */
746 			case 1:		/* `..' */
747 				dp->d_fileno = PROCFS_FILENO(0, Proot);
748 				dp->d_namlen = i + 1;
749 				bcopy("..", dp->d_name, dp->d_namlen);
750 				dp->d_name[i + 1] = '\0';
751 				dp->d_type = DT_DIR;
752 				break;
753 
754 			case 2:
755 				dp->d_fileno = PROCFS_FILENO(0, Pcurproc);
756 				dp->d_namlen = 7;
757 				bcopy("curproc", dp->d_name, 8);
758 				dp->d_type = DT_LNK;
759 				break;
760 
761 			default:
762 				while (pcnt < i) {
763 					pcnt++;
764 					p = p->p_list.le_next;
765 					if (!p)
766 						goto done;
767 				}
768 				dp->d_fileno = PROCFS_FILENO(p->p_pid, Pproc);
769 				dp->d_namlen = sprintf(dp->d_name, "%ld",
770 				    (long)p->p_pid);
771 				dp->d_type = DT_REG;
772 				p = p->p_list.le_next;
773 				break;
774 			}
775 
776 			if (error = uiomove((caddr_t)dp, UIO_MX, uio))
777 				break;
778 		}
779 	done:
780 
781 #ifdef PROCFS_ZOMBIE
782 		if (p == 0 && doingzomb == 0) {
783 			doingzomb = 1;
784 			p = zombproc.lh_first;
785 			goto again;
786 		}
787 #endif
788 
789 		break;
790 
791 	    }
792 
793 	default:
794 		error = ENOTDIR;
795 		break;
796 	}
797 
798 	uio->uio_offset = i * UIO_MX;
799 
800 	return (error);
801 }
802 
803 /*
804  * readlink reads the link of `curproc'
805  */
806 procfs_readlink(ap)
807 	struct vop_readlink_args *ap;
808 {
809 	struct uio *uio = ap->a_uio;
810 	char buf[16];		/* should be enough */
811 	int len;
812 
813 	if (VTOPFS(ap->a_vp)->pfs_fileno != PROCFS_FILENO(0, Pcurproc))
814 		return (EINVAL);
815 
816 	len = sprintf(buf, "%ld", (long)curproc->p_pid);
817 
818 	return (uiomove((caddr_t)buf, len, ap->a_uio));
819 }
820 
821 /*
822  * convert decimal ascii to pid_t
823  */
824 static pid_t
825 atopid(b, len)
826 	const char *b;
827 	u_int len;
828 {
829 	pid_t p = 0;
830 
831 	while (len--) {
832 		char c = *b++;
833 		if (c < '0' || c > '9')
834 			return (NO_PID);
835 		p = 10 * p + (c - '0');
836 		if (p > PID_MAX)
837 			return (NO_PID);
838 	}
839 
840 	return (p);
841 }
842 
843 /*
844  * procfs vnode operations.
845  */
846 int (**procfs_vnodeop_p)();
847 struct vnodeopv_entry_desc procfs_vnodeop_entries[] = {
848 	{ &vop_default_desc, vn_default_error },
849 	{ &vop_lookup_desc, procfs_lookup },		/* lookup */
850 	{ &vop_create_desc, procfs_create },		/* create */
851 	{ &vop_mknod_desc, procfs_mknod },		/* mknod */
852 	{ &vop_open_desc, procfs_open },		/* open */
853 	{ &vop_close_desc, procfs_close },		/* close */
854 	{ &vop_access_desc, procfs_access },		/* access */
855 	{ &vop_getattr_desc, procfs_getattr },		/* getattr */
856 	{ &vop_setattr_desc, procfs_setattr },		/* setattr */
857 	{ &vop_read_desc, procfs_read },		/* read */
858 	{ &vop_write_desc, procfs_write },		/* write */
859 	{ &vop_ioctl_desc, procfs_ioctl },		/* ioctl */
860 	{ &vop_select_desc, procfs_select },		/* select */
861 	{ &vop_mmap_desc, procfs_mmap },		/* mmap */
862 	{ &vop_fsync_desc, procfs_fsync },		/* fsync */
863 	{ &vop_seek_desc, procfs_seek },		/* seek */
864 	{ &vop_remove_desc, procfs_remove },		/* remove */
865 	{ &vop_link_desc, procfs_link },		/* link */
866 	{ &vop_rename_desc, procfs_rename },		/* rename */
867 	{ &vop_mkdir_desc, procfs_mkdir },		/* mkdir */
868 	{ &vop_rmdir_desc, procfs_rmdir },		/* rmdir */
869 	{ &vop_symlink_desc, procfs_symlink },		/* symlink */
870 	{ &vop_readdir_desc, procfs_readdir },		/* readdir */
871 	{ &vop_readlink_desc, procfs_readlink },	/* readlink */
872 	{ &vop_abortop_desc, procfs_abortop },		/* abortop */
873 	{ &vop_inactive_desc, procfs_inactive },	/* inactive */
874 	{ &vop_reclaim_desc, procfs_reclaim },		/* reclaim */
875 	{ &vop_lock_desc, procfs_lock },		/* lock */
876 	{ &vop_unlock_desc, procfs_unlock },		/* unlock */
877 	{ &vop_bmap_desc, procfs_bmap },		/* bmap */
878 	{ &vop_strategy_desc, procfs_strategy },	/* strategy */
879 	{ &vop_print_desc, procfs_print },		/* print */
880 	{ &vop_islocked_desc, procfs_islocked },	/* islocked */
881 	{ &vop_pathconf_desc, procfs_pathconf },	/* pathconf */
882 	{ &vop_advlock_desc, procfs_advlock },		/* advlock */
883 	{ &vop_blkatoff_desc, procfs_blkatoff },	/* blkatoff */
884 	{ &vop_valloc_desc, procfs_valloc },		/* valloc */
885 	{ &vop_vfree_desc, procfs_vfree },		/* vfree */
886 	{ &vop_truncate_desc, procfs_truncate },	/* truncate */
887 	{ &vop_update_desc, procfs_update },		/* update */
888 	{ (struct vnodeop_desc*)NULL, (int(*)())NULL }
889 };
890 struct vnodeopv_desc procfs_vnodeop_opv_desc =
891 	{ &procfs_vnodeop_p, procfs_vnodeop_entries };
892