xref: /netbsd-src/sys/dev/putter/putter.c (revision 3816d47b2c42fcd6e549e3407f842a5b1a1d23ad) 
1 /*	$NetBSD: putter.c,v 1.26 2009/12/20 09:36:05 dsl Exp $	*/
2 
3 /*
4  * Copyright (c) 2006, 2007  Antti Kantee.  All Rights Reserved.
5  *
6  * Development of this software was supported by the
7  * Ulla Tuominen Foundation and the Finnish Cultural Foundation and the
8  * Research Foundation of Helsinki University of Technology
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  *
19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
20  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
21  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
22  * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
25  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 /*
33  * Pass-to-Userspace TransporTER: generic kernel-user request-response
34  * transport interface.
35  */
36 
37 #include <sys/cdefs.h>
38 __KERNEL_RCSID(0, "$NetBSD: putter.c,v 1.26 2009/12/20 09:36:05 dsl Exp $");
39 
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/conf.h>
43 #include <sys/file.h>
44 #include <sys/filedesc.h>
45 #include <sys/kmem.h>
46 #include <sys/poll.h>
47 #include <sys/stat.h>
48 #include <sys/socketvar.h>
49 #include <sys/module.h>
50 #include <sys/kauth.h>
51 
52 #include <dev/putter/putter_sys.h>
53 
54 /*
55  * Device routines.  These are for when /dev/puffs is initially
56  * opened before it has been cloned.
57  */
58 
59 dev_type_open(puttercdopen);
60 dev_type_close(puttercdclose);
61 dev_type_ioctl(puttercdioctl);
62 
63 /* dev */
64 const struct cdevsw putter_cdevsw = {
65 	puttercdopen,	puttercdclose,	noread,		nowrite,
66 	noioctl,	nostop,		notty,		nopoll,
67 	nommap,		nokqfilter,	D_OTHER
68 };
69 
70 /*
71  * Configuration data.
72  *
73  * This is static-size for now.  Will be redone for devfs.
74  */
75 
76 #define PUTTER_CONFSIZE 16
77 
78 static struct putter_config {
79 	int	pc_minor;
80 	int	(*pc_config)(int, int, int);
81 } putterconf[PUTTER_CONFSIZE];
82 
83 static int
84 putter_configure(dev_t dev, int flags, int fmt, int fd)
85 {
86 	struct putter_config *pc;
87 
88 	/* are we the catch-all node? */
89 	if (minor(dev) == PUTTER_MINOR_WILDCARD
90 	    || minor(dev) == PUTTER_MINOR_COMPAT)
91 		return 0;
92 
93 	/* nopes?  try to configure us */
94 	for (pc = putterconf; pc->pc_config; pc++)
95 		if (minor(dev) == pc->pc_minor)
96 			return pc->pc_config(fd, flags, fmt);
97 	return ENXIO;
98 }
99 
100 int
101 putter_register(putter_config_fn pcfn, int minor)
102 {
103 	int i;
104 
105 	for (i = 0; i < PUTTER_CONFSIZE; i++)
106 		if (putterconf[i].pc_config == NULL)
107 			break;
108 	if (i == PUTTER_CONFSIZE)
109 		return EBUSY;
110 
111 	putterconf[i].pc_minor = minor;
112 	putterconf[i].pc_config = pcfn;
113 	return 0;
114 }
115 
116 /*
117  * putter instance structures.  these are always allocated and freed
118  * from the context of the transport user.
119  */
120 struct putter_instance {
121 	pid_t			pi_pid;
122 	int			pi_idx;
123 	int			pi_fd;
124 	struct selinfo		pi_sel;
125 
126 	void			*pi_private;
127 	struct putter_ops	*pi_pop;
128 
129 	uint8_t			*pi_curput;
130 	size_t			pi_curres;
131 	void			*pi_curopaq;
132 	struct timespec		pi_atime;
133 	struct timespec		pi_mtime;
134 	struct timespec		pi_btime;
135 
136 	TAILQ_ENTRY(putter_instance) pi_entries;
137 };
138 #define PUTTER_EMBRYO ((void *)-1)	/* before attach	*/
139 #define PUTTER_DEAD ((void *)-2)	/* after detach		*/
140 
141 static TAILQ_HEAD(, putter_instance) putter_ilist
142     = TAILQ_HEAD_INITIALIZER(putter_ilist);
143 
144 static int get_pi_idx(struct putter_instance *);
145 
146 #ifdef DEBUG
147 #ifndef PUTTERDEBUG
148 #define PUTTERDEBUG
149 #endif
150 #endif
151 
152 #ifdef PUTTERDEBUG
153 int putterdebug = 0;
154 #define DPRINTF(x) if (putterdebug > 0) printf x
155 #define DPRINTF_VERBOSE(x) if (putterdebug > 1) printf x
156 #else
157 #define DPRINTF(x)
158 #define DPRINTF_VERBOSE(x)
159 #endif
160 
161 /*
162  * public init / deinit
163  */
164 
165 /* protects both the list and the contents of the list elements */
166 static kmutex_t pi_mtx;
167 
168 void putterattach(void);
169 
170 void
171 putterattach(void)
172 {
173 
174 	mutex_init(&pi_mtx, MUTEX_DEFAULT, IPL_NONE);
175 }
176 
177 #if 0
178 void
179 putter_destroy(void)
180 {
181 
182 	mutex_destroy(&pi_mtx);
183 }
184 #endif
185 
186 /*
187  * fd routines, for cloner
188  */
189 static int putter_fop_read(file_t *, off_t *, struct uio *,
190 			   kauth_cred_t, int);
191 static int putter_fop_write(file_t *, off_t *, struct uio *,
192 			    kauth_cred_t, int);
193 static int putter_fop_ioctl(file_t*, u_long, void *);
194 static int putter_fop_poll(file_t *, int);
195 static int putter_fop_stat(file_t *, struct stat *);
196 static int putter_fop_close(file_t *);
197 static int putter_fop_kqfilter(file_t *, struct knote *);
198 
199 
200 static const struct fileops putter_fileops = {
201 	.fo_read = putter_fop_read,
202 	.fo_write = putter_fop_write,
203 	.fo_ioctl = putter_fop_ioctl,
204 	.fo_fcntl = fnullop_fcntl,
205 	.fo_poll = putter_fop_poll,
206 	.fo_stat = putter_fop_stat,
207 	.fo_close = putter_fop_close,
208 	.fo_kqfilter = putter_fop_kqfilter,
209 	.fo_restart = fnullop_restart,
210 };
211 
212 static int
213 putter_fop_read(file_t *fp, off_t *off, struct uio *uio,
214 	kauth_cred_t cred, int flags)
215 {
216 	struct putter_instance *pi = fp->f_data;
217 	size_t origres, moved;
218 	int error;
219 
220 	KERNEL_LOCK(1, NULL);
221 	getnanotime(&pi->pi_atime);
222 
223 	if (pi->pi_private == PUTTER_EMBRYO || pi->pi_private == PUTTER_DEAD) {
224 		printf("putter_fop_read: private %d not inited\n", pi->pi_idx);
225 		KERNEL_UNLOCK_ONE(NULL);
226 		return ENOENT;
227 	}
228 
229 	if (pi->pi_curput == NULL) {
230 		error = pi->pi_pop->pop_getout(pi->pi_private, uio->uio_resid,
231 		    fp->f_flag & O_NONBLOCK, &pi->pi_curput,
232 		    &pi->pi_curres, &pi->pi_curopaq);
233 		if (error) {
234 			KERNEL_UNLOCK_ONE(NULL);
235 			return error;
236 		}
237 	}
238 
239 	origres = uio->uio_resid;
240 	error = uiomove(pi->pi_curput, pi->pi_curres, uio);
241 	moved = origres - uio->uio_resid;
242 	DPRINTF(("putter_fop_read (%p): moved %zu bytes from %p, error %d\n",
243 	    pi, moved, pi->pi_curput, error));
244 
245 	KASSERT(pi->pi_curres >= moved);
246 	pi->pi_curres -= moved;
247 	pi->pi_curput += moved;
248 
249 	if (pi->pi_curres == 0) {
250 		pi->pi_pop->pop_releaseout(pi->pi_private,
251 		    pi->pi_curopaq, error);
252 		pi->pi_curput = NULL;
253 	}
254 
255 	KERNEL_UNLOCK_ONE(NULL);
256 	return error;
257 }
258 
259 static int
260 putter_fop_write(file_t *fp, off_t *off, struct uio *uio,
261 	kauth_cred_t cred, int flags)
262 {
263 	struct putter_instance *pi = fp->f_data;
264 	struct putter_hdr pth;
265 	uint8_t *buf;
266 	size_t frsize;
267 	int error;
268 
269 	KERNEL_LOCK(1, NULL);
270 	getnanotime(&pi->pi_mtime);
271 
272 	DPRINTF(("putter_fop_write (%p): writing response, resid %zu\n",
273 	    pi->pi_private, uio->uio_resid));
274 
275 	if (pi->pi_private == PUTTER_EMBRYO || pi->pi_private == PUTTER_DEAD) {
276 		printf("putter_fop_write: putter %d not inited\n", pi->pi_idx);
277 		KERNEL_UNLOCK_ONE(NULL);
278 		return ENOENT;
279 	}
280 
281 	error = uiomove(&pth, sizeof(struct putter_hdr), uio);
282 	if (error) {
283 		KERNEL_UNLOCK_ONE(NULL);
284 		return error;
285 	}
286 
287 	/* Sorry mate, the kernel doesn't buffer. */
288 	frsize = pth.pth_framelen - sizeof(struct putter_hdr);
289 	if (uio->uio_resid < frsize) {
290 		KERNEL_UNLOCK_ONE(NULL);
291 		return EINVAL;
292 	}
293 
294 	buf = kmem_alloc(frsize + sizeof(struct putter_hdr), KM_SLEEP);
295 	memcpy(buf, &pth, sizeof(pth));
296 	error = uiomove(buf+sizeof(struct putter_hdr), frsize, uio);
297 	if (error == 0) {
298 		pi->pi_pop->pop_dispatch(pi->pi_private,
299 		    (struct putter_hdr *)buf);
300 	}
301 	kmem_free(buf, frsize + sizeof(struct putter_hdr));
302 
303 	KERNEL_UNLOCK_ONE(NULL);
304 	return error;
305 }
306 
307 /*
308  * Poll query interface.  The question is only if an event
309  * can be read from us.
310  */
311 #define PUTTERPOLL_EVSET (POLLIN | POLLRDNORM | POLLRDBAND | POLLPRI)
312 static int
313 putter_fop_poll(file_t *fp, int events)
314 {
315 	struct putter_instance *pi = fp->f_data;
316 	int revents;
317 
318 	KERNEL_LOCK(1, NULL);
319 
320 	if (pi->pi_private == PUTTER_EMBRYO || pi->pi_private == PUTTER_DEAD) {
321 		printf("putter_fop_ioctl: putter %d not inited\n", pi->pi_idx);
322 		KERNEL_UNLOCK_ONE(NULL);
323 		return ENOENT;
324 	}
325 
326 	revents = events & (POLLOUT | POLLWRNORM | POLLWRBAND);
327 	if ((events & PUTTERPOLL_EVSET) == 0) {
328 		KERNEL_UNLOCK_ONE(NULL);
329 		return revents;
330 	}
331 
332 	/* check queue */
333 	if (pi->pi_pop->pop_waitcount(pi->pi_private))
334 		revents |= PUTTERPOLL_EVSET;
335 	else
336 		selrecord(curlwp, &pi->pi_sel);
337 
338 	KERNEL_UNLOCK_ONE(NULL);
339 	return revents;
340 }
341 
342 /*
343  * device close = forced unmount.
344  *
345  * unmounting is a frightfully complex operation to avoid races
346  */
347 static int
348 putter_fop_close(file_t *fp)
349 {
350 	struct putter_instance *pi = fp->f_data;
351 	int rv;
352 
353 	DPRINTF(("putter_fop_close: device closed\n"));
354 
355 	KERNEL_LOCK(1, NULL);
356 
357  restart:
358 	mutex_enter(&pi_mtx);
359 	/*
360 	 * First check if the fs was never mounted.  In that case
361 	 * remove the instance from the list.  If mount is attempted later,
362 	 * it will simply fail.
363 	 */
364 	if (pi->pi_private == PUTTER_EMBRYO) {
365 		TAILQ_REMOVE(&putter_ilist, pi, pi_entries);
366 		mutex_exit(&pi_mtx);
367 
368 		DPRINTF(("putter_fop_close: data associated with fp %p was "
369 		    "embryonic\n", fp));
370 
371 		goto out;
372 	}
373 
374 	/*
375 	 * Next, analyze if unmount was called and the instance is dead.
376 	 * In this case we can just free the structure and go home, it
377 	 * was removed from the list by putter_rmprivate().
378 	 */
379 	if (pi->pi_private == PUTTER_DEAD) {
380 		mutex_exit(&pi_mtx);
381 
382 		DPRINTF(("putter_fop_close: putter associated with fp %p (%d) "
383 		    "dead, freeing\n", fp, pi->pi_idx));
384 
385 		goto out;
386 	}
387 
388 	/*
389 	 * So we have a reference.  Proceed to unwrap the file system.
390 	 */
391 	mutex_exit(&pi_mtx);
392 
393 	/* hmm?  suspicious locking? */
394 	while ((rv = pi->pi_pop->pop_close(pi->pi_private)) == ERESTART)
395 		goto restart;
396 
397  out:
398 	KERNEL_UNLOCK_ONE(NULL);
399 	/*
400 	 * Finally, release the instance information.  It was already
401 	 * removed from the list by putter_rmprivate() and we know it's
402 	 * dead, so no need to lock.
403 	 */
404 	kmem_free(pi, sizeof(struct putter_instance));
405 
406 	return 0;
407 }
408 
409 static int
410 putter_fop_stat(file_t *fp, struct stat *st)
411 {
412 	struct putter_instance *pi = fp->f_data;
413 
414 	(void)memset(st, 0, sizeof(*st));
415 	KERNEL_LOCK(1, NULL);
416 	st->st_dev = makedev(cdevsw_lookup_major(&putter_cdevsw), pi->pi_idx);
417 	st->st_atimespec = pi->pi_atime;
418 	st->st_mtimespec = pi->pi_mtime;
419 	st->st_ctimespec = st->st_birthtimespec = pi->pi_btime;
420 	st->st_uid = kauth_cred_geteuid(fp->f_cred);
421 	st->st_gid = kauth_cred_getegid(fp->f_cred);
422 	KERNEL_UNLOCK_ONE(NULL);
423 	return 0;
424 }
425 
426 static int
427 putter_fop_ioctl(file_t *fp, u_long cmd, void *data)
428 {
429 
430 	/*
431 	 * work already done in sys_ioctl().  skip sanity checks to enable
432 	 * setting non-blocking fd without yet having mounted the fs
433 	 */
434 	if (cmd == FIONBIO)
435 		return 0;
436 
437 	return EINVAL;
438 }
439 
440 /* kqueue stuff */
441 
442 static void
443 filt_putterdetach(struct knote *kn)
444 {
445 	struct putter_instance *pi = kn->kn_hook;
446 
447 	KERNEL_LOCK(1, NULL);
448 	mutex_enter(&pi_mtx);
449 	SLIST_REMOVE(&pi->pi_sel.sel_klist, kn, knote, kn_selnext);
450 	mutex_exit(&pi_mtx);
451 	KERNEL_UNLOCK_ONE(NULL);
452 }
453 
454 static int
455 filt_putter(struct knote *kn, long hint)
456 {
457 	struct putter_instance *pi = kn->kn_hook;
458 	int error, rv;
459 
460 	KERNEL_LOCK(1, NULL);
461 	error = 0;
462 	mutex_enter(&pi_mtx);
463 	if (pi->pi_private == PUTTER_EMBRYO || pi->pi_private == PUTTER_DEAD)
464 		error = 1;
465 	mutex_exit(&pi_mtx);
466 	if (error) {
467 		KERNEL_UNLOCK_ONE(NULL);
468 		return 0;
469 	}
470 
471 	kn->kn_data = pi->pi_pop->pop_waitcount(pi->pi_private);
472 	rv = kn->kn_data != 0;
473 	KERNEL_UNLOCK_ONE(NULL);
474 	return rv;
475 }
476 
477 static const struct filterops putter_filtops =
478 	{ 1, NULL, filt_putterdetach, filt_putter };
479 
480 static int
481 putter_fop_kqfilter(file_t *fp, struct knote *kn)
482 {
483 	struct putter_instance *pi = fp->f_data;
484 	struct klist *klist;
485 
486 	KERNEL_LOCK(1, NULL);
487 
488 	switch (kn->kn_filter) {
489 	case EVFILT_READ:
490 		klist = &pi->pi_sel.sel_klist;
491 		kn->kn_fop = &putter_filtops;
492 		kn->kn_hook = pi;
493 
494 		mutex_enter(&pi_mtx);
495 		SLIST_INSERT_HEAD(klist, kn, kn_selnext);
496 		mutex_exit(&pi_mtx);
497 
498 		break;
499 	case EVFILT_WRITE:
500 		kn->kn_fop = &seltrue_filtops;
501 		break;
502 	default:
503 		KERNEL_UNLOCK_ONE(NULL);
504 		return EINVAL;
505 	}
506 
507 	KERNEL_UNLOCK_ONE(NULL);
508 	return 0;
509 }
510 
511 int
512 puttercdopen(dev_t dev, int flags, int fmt, struct lwp *l)
513 {
514 	struct putter_instance *pi;
515 	file_t *fp;
516 	int error, fd, idx;
517 	proc_t *p;
518 
519 	p = curproc;
520 	pi = kmem_alloc(sizeof(struct putter_instance), KM_SLEEP);
521 	mutex_enter(&pi_mtx);
522 	idx = get_pi_idx(pi);
523 
524 	pi->pi_pid = p->p_pid;
525 	pi->pi_idx = idx;
526 	pi->pi_curput = NULL;
527 	pi->pi_curres = 0;
528 	pi->pi_curopaq = NULL;
529 	getnanotime(&pi->pi_btime);
530 	pi->pi_atime = pi->pi_mtime = pi->pi_btime;
531 	selinit(&pi->pi_sel);
532 	mutex_exit(&pi_mtx);
533 
534 	if ((error = fd_allocfile(&fp, &fd)) != 0)
535 		goto bad1;
536 
537 	if ((error = putter_configure(dev, flags, fmt, fd)) != 0)
538 		goto bad2;
539 
540 	DPRINTF(("puttercdopen: registered embryonic pmp for pid: %d\n",
541 	    pi->pi_pid));
542 
543 	error = fd_clone(fp, fd, FREAD|FWRITE, &putter_fileops, pi);
544 	KASSERT(error == EMOVEFD);
545 	return error;
546 
547  bad2:
548  	fd_abort(p, fp, fd);
549  bad1:
550 	putter_detach(pi);
551 	kmem_free(pi, sizeof(struct putter_instance));
552 	return error;
553 }
554 
555 int
556 puttercdclose(dev_t dev, int flags, int fmt, struct lwp *l)
557 {
558 
559 	panic("puttercdclose impossible\n");
560 
561 	return 0;
562 }
563 
564 
565 /*
566  * Set the private structure for the file descriptor.  This is
567  * typically done immediately when the counterpart has knowledge
568  * about the private structure's address and the file descriptor
569  * (e.g. vfs mount routine).
570  *
571  * We only want to make sure that the caller had the right to open the
572  * device, we don't so much care about which context it gets in case
573  * the same process opened multiple (since they are equal at this point).
574  */
575 struct putter_instance *
576 putter_attach(pid_t pid, int fd, void *ppriv, struct putter_ops *pop)
577 {
578 	struct putter_instance *pi = NULL;
579 
580 	mutex_enter(&pi_mtx);
581 	TAILQ_FOREACH(pi, &putter_ilist, pi_entries) {
582 		if (pi->pi_pid == pid && pi->pi_private == PUTTER_EMBRYO) {
583 			pi->pi_private = ppriv;
584 			pi->pi_fd = fd;
585 			pi->pi_pop = pop;
586 			break;
587 		    }
588 	}
589 	mutex_exit(&pi_mtx);
590 
591 	DPRINTF(("putter_setprivate: pi at %p (%d/%d)\n", pi,
592 	    pi ? pi->pi_pid : 0, pi ? pi->pi_fd : 0));
593 
594 	return pi;
595 }
596 
597 /*
598  * Remove fp <-> private mapping.
599  */
600 void
601 putter_detach(struct putter_instance *pi)
602 {
603 
604 	mutex_enter(&pi_mtx);
605 	TAILQ_REMOVE(&putter_ilist, pi, pi_entries);
606 	pi->pi_private = PUTTER_DEAD;
607 	mutex_exit(&pi_mtx);
608 
609 	DPRINTF(("putter_nukebypmp: nuked %p\n", pi));
610 }
611 
612 void
613 putter_notify(struct putter_instance *pi)
614 {
615 
616 	selnotify(&pi->pi_sel, 0, 0);
617 }
618 
619 /* search sorted list of instances for free minor, sorted insert arg */
620 static int
621 get_pi_idx(struct putter_instance *pi_i)
622 {
623 	struct putter_instance *pi;
624 	int i;
625 
626 	KASSERT(mutex_owned(&pi_mtx));
627 
628 	i = 0;
629 	TAILQ_FOREACH(pi, &putter_ilist, pi_entries) {
630 		if (i != pi->pi_idx)
631 			break;
632 		i++;
633 	}
634 
635 	pi_i->pi_private = PUTTER_EMBRYO;
636 
637 	if (pi == NULL)
638 		TAILQ_INSERT_TAIL(&putter_ilist, pi_i, pi_entries);
639 	else
640 		TAILQ_INSERT_BEFORE(pi, pi_i, pi_entries);
641 
642 	return i;
643 }
644 
645 MODULE(MODULE_CLASS_DRIVER, putter, NULL);
646 
647 static int
648 putter_modcmd(modcmd_t cmd, void *arg)
649 {
650 #ifdef _MODULE
651 	devmajor_t bmajor = NODEVMAJOR, cmajor = NODEVMAJOR;
652 
653 	switch (cmd) {
654 	case MODULE_CMD_INIT:
655 		return devsw_attach("putter", NULL, &bmajor,
656 		    &putter_cdevsw, &cmajor);
657 	case MODULE_CMD_FINI:
658 		return devsw_detach(NULL, &putter_cdevsw);
659 	default:
660 		return ENOTTY;
661 	}
662 #else
663 	if (cmd == MODULE_CMD_INIT)
664 		return 0;
665 	return ENOTTY;
666 #endif
667 }
668