xref: /netbsd-src/sys/dev/putter/putter.c (revision 466a16a118933bd295a8a104f095714fadf9cf68) 
1 /*	$NetBSD: putter.c,v 1.16 2008/08/08 13:02:10 pooka 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 1.16 2008/08/08 13:02:10 pooka 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/socketvar.h>
48 #include <sys/module.h>
49 
50 #include <dev/putter/putter_sys.h>
51 
52 /*
53  * Configuration data.
54  *
55  * This is static-size for now.  Will be redone for devfs.
56  */
57 
58 #define PUTTER_CONFSIZE 16
59 
60 static struct putter_config {
61 	int	pc_minor;
62 	int	(*pc_config)(int, int, int);
63 } putterconf[PUTTER_CONFSIZE];
64 
65 static int
66 putter_configure(dev_t dev, int flags, int fmt, int fd)
67 {
68 	struct putter_config *pc;
69 
70 	/* are we the catch-all node? */
71 	if (minor(dev) == PUTTER_MINOR_WILDCARD
72 	    || minor(dev) == PUTTER_MINOR_COMPAT)
73 		return 0;
74 
75 	/* nopes?  try to configure us */
76 	for (pc = putterconf; pc->pc_config; pc++)
77 		if (minor(dev) == pc->pc_minor)
78 			return pc->pc_config(fd, flags, fmt);
79 	return ENXIO;
80 }
81 
82 int
83 putter_register(putter_config_fn pcfn, int minor)
84 {
85 	int i;
86 
87 	for (i = 0; i < PUTTER_CONFSIZE; i++)
88 		if (putterconf[i].pc_config == NULL)
89 			break;
90 	if (i == PUTTER_CONFSIZE)
91 		return EBUSY;
92 
93 	putterconf[i].pc_minor = minor;
94 	putterconf[i].pc_config = pcfn;
95 	return 0;
96 }
97 
98 /*
99  * putter instance structures.  these are always allocated and freed
100  * from the context of the transport user.
101  */
102 struct putter_instance {
103 	pid_t			pi_pid;
104 	int			pi_idx;
105 	int			pi_fd;
106 	struct selinfo		pi_sel;
107 
108 	void			*pi_private;
109 	struct putter_ops	*pi_pop;
110 
111 	uint8_t			*pi_curput;
112 	size_t			pi_curres;
113 	void			*pi_curopaq;
114 
115 	TAILQ_ENTRY(putter_instance) pi_entries;
116 };
117 #define PUTTER_EMBRYO ((void *)-1)	/* before attach	*/
118 #define PUTTER_DEAD ((void *)-2)	/* after detach		*/
119 
120 static TAILQ_HEAD(, putter_instance) putter_ilist
121     = TAILQ_HEAD_INITIALIZER(putter_ilist);
122 
123 static int get_pi_idx(struct putter_instance *);
124 
125 #ifdef DEBUG
126 #ifndef PUTTERDEBUG
127 #define PUTTERDEBUG
128 #endif
129 #endif
130 
131 #ifdef PUTTERDEBUG
132 int putterdebug = 0;
133 #define DPRINTF(x) if (putterdebug > 0) printf x
134 #define DPRINTF_VERBOSE(x) if (putterdebug > 1) printf x
135 #else
136 #define DPRINTF(x)
137 #define DPRINTF_VERBOSE(x)
138 #endif
139 
140 /*
141  * public init / deinit
142  */
143 
144 /* protects both the list and the contents of the list elements */
145 static kmutex_t pi_mtx;
146 
147 void putterattach(void);
148 
149 void
150 putterattach()
151 {
152 
153 	mutex_init(&pi_mtx, MUTEX_DEFAULT, IPL_NONE);
154 }
155 
156 #if 0
157 void
158 putter_destroy()
159 {
160 
161 	mutex_destroy(&pi_mtx);
162 }
163 #endif
164 
165 /*
166  * fd routines, for cloner
167  */
168 static int putter_fop_read(file_t *, off_t *, struct uio *,
169 			   kauth_cred_t, int);
170 static int putter_fop_write(file_t *, off_t *, struct uio *,
171 			    kauth_cred_t, int);
172 static int putter_fop_ioctl(file_t*, u_long, void *);
173 static int putter_fop_poll(file_t *, int);
174 static int putter_fop_close(file_t *);
175 static int putter_fop_kqfilter(file_t *, struct knote *);
176 
177 
178 static const struct fileops putter_fileops = {
179 	putter_fop_read,
180 	putter_fop_write,
181 	putter_fop_ioctl,
182 	fnullop_fcntl,
183 	putter_fop_poll,
184 	fbadop_stat,
185 	putter_fop_close,
186 	putter_fop_kqfilter
187 };
188 
189 static int
190 putter_fop_read(file_t *fp, off_t *off, struct uio *uio,
191 	kauth_cred_t cred, int flags)
192 {
193 	struct putter_instance *pi = fp->f_data;
194 	size_t origres, moved;
195 	int error;
196 
197 	KERNEL_LOCK(1, NULL);
198 
199 	if (pi->pi_private == PUTTER_EMBRYO || pi->pi_private == PUTTER_DEAD) {
200 		printf("putter_fop_read: private %d not inited\n", pi->pi_idx);
201 		KERNEL_UNLOCK_ONE(NULL);
202 		return ENOENT;
203 	}
204 
205 	if (pi->pi_curput == NULL) {
206 		error = pi->pi_pop->pop_getout(pi->pi_private, uio->uio_resid,
207 		    fp->f_flag & O_NONBLOCK, &pi->pi_curput,
208 		    &pi->pi_curres, &pi->pi_curopaq);
209 		if (error) {
210 			KERNEL_UNLOCK_ONE(NULL);
211 			return error;
212 		}
213 	}
214 
215 	origres = uio->uio_resid;
216 	error = uiomove(pi->pi_curput, pi->pi_curres, uio);
217 	moved = origres - uio->uio_resid;
218 	DPRINTF(("putter_fop_read (%p): moved %zu bytes from %p, error %d\n",
219 	    pi, moved, pi->pi_curput, error));
220 
221 	KASSERT(pi->pi_curres >= moved);
222 	pi->pi_curres -= moved;
223 	pi->pi_curput += moved;
224 
225 	if (pi->pi_curres == 0) {
226 		pi->pi_pop->pop_releaseout(pi->pi_private,
227 		    pi->pi_curopaq, error);
228 		pi->pi_curput = NULL;
229 	}
230 
231 	KERNEL_UNLOCK_ONE(NULL);
232 	return error;
233 }
234 
235 static int
236 putter_fop_write(file_t *fp, off_t *off, struct uio *uio,
237 	kauth_cred_t cred, int flags)
238 {
239 	struct putter_instance *pi = fp->f_data;
240 	struct putter_hdr pth;
241 	uint8_t *buf;
242 	size_t frsize;
243 	int error;
244 
245 	KERNEL_LOCK(1, NULL);
246 
247 	DPRINTF(("putter_fop_write (%p): writing response, resid %zu\n",
248 	    pi->pi_private, uio->uio_resid));
249 
250 	if (pi->pi_private == PUTTER_EMBRYO || pi->pi_private == PUTTER_DEAD) {
251 		printf("putter_fop_write: putter %d not inited\n", pi->pi_idx);
252 		KERNEL_UNLOCK_ONE(NULL);
253 		return ENOENT;
254 	}
255 
256 	error = uiomove(&pth, sizeof(struct putter_hdr), uio);
257 	if (error) {
258 		KERNEL_UNLOCK_ONE(NULL);
259 		return error;
260 	}
261 
262 	/* Sorry mate, the kernel doesn't buffer. */
263 	frsize = pth.pth_framelen - sizeof(struct putter_hdr);
264 	if (uio->uio_resid < frsize) {
265 		KERNEL_UNLOCK_ONE(NULL);
266 		return EINVAL;
267 	}
268 
269 	buf = kmem_alloc(frsize + sizeof(struct putter_hdr), KM_SLEEP);
270 	memcpy(buf, &pth, sizeof(pth));
271 	error = uiomove(buf+sizeof(struct putter_hdr), frsize, uio);
272 	if (error == 0) {
273 		pi->pi_pop->pop_dispatch(pi->pi_private,
274 		    (struct putter_hdr *)buf);
275 	}
276 	kmem_free(buf, frsize + sizeof(struct putter_hdr));
277 
278 	KERNEL_UNLOCK_ONE(NULL);
279 	return error;
280 }
281 
282 /*
283  * Poll query interface.  The question is only if an event
284  * can be read from us.
285  */
286 #define PUTTERPOLL_EVSET (POLLIN | POLLRDNORM | POLLRDBAND | POLLPRI)
287 static int
288 putter_fop_poll(file_t *fp, int events)
289 {
290 	struct putter_instance *pi = fp->f_data;
291 	int revents;
292 
293 	KERNEL_LOCK(1, NULL);
294 
295 	if (pi->pi_private == PUTTER_EMBRYO || pi->pi_private == PUTTER_DEAD) {
296 		printf("putter_fop_ioctl: putter %d not inited\n", pi->pi_idx);
297 		KERNEL_UNLOCK_ONE(NULL);
298 		return ENOENT;
299 	}
300 
301 	revents = events & (POLLOUT | POLLWRNORM | POLLWRBAND);
302 	if ((events & PUTTERPOLL_EVSET) == 0) {
303 		KERNEL_UNLOCK_ONE(NULL);
304 		return revents;
305 	}
306 
307 	/* check queue */
308 	if (pi->pi_pop->pop_waitcount(pi->pi_private))
309 		revents |= PUTTERPOLL_EVSET;
310 	else
311 		selrecord(curlwp, &pi->pi_sel);
312 
313 	KERNEL_UNLOCK_ONE(NULL);
314 	return revents;
315 }
316 
317 /*
318  * device close = forced unmount.
319  *
320  * unmounting is a frightfully complex operation to avoid races
321  */
322 static int
323 putter_fop_close(file_t *fp)
324 {
325 	struct putter_instance *pi = fp->f_data;
326 	int rv;
327 
328 	DPRINTF(("putter_fop_close: device closed\n"));
329 
330 	KERNEL_LOCK(1, NULL);
331 
332  restart:
333 	mutex_enter(&pi_mtx);
334 	/*
335 	 * First check if the fs was never mounted.  In that case
336 	 * remove the instance from the list.  If mount is attempted later,
337 	 * it will simply fail.
338 	 */
339 	if (pi->pi_private == PUTTER_EMBRYO) {
340 		TAILQ_REMOVE(&putter_ilist, pi, pi_entries);
341 		mutex_exit(&pi_mtx);
342 
343 		DPRINTF(("putter_fop_close: data associated with fp %p was "
344 		    "embryonic\n", fp));
345 
346 		goto out;
347 	}
348 
349 	/*
350 	 * Next, analyze if unmount was called and the instance is dead.
351 	 * In this case we can just free the structure and go home, it
352 	 * was removed from the list by putter_rmprivate().
353 	 */
354 	if (pi->pi_private == PUTTER_DEAD) {
355 		mutex_exit(&pi_mtx);
356 
357 		DPRINTF(("putter_fop_close: putter associated with fp %p (%d) "
358 		    "dead, freeing\n", fp, pi->pi_idx));
359 
360 		goto out;
361 	}
362 
363 	/*
364 	 * So we have a reference.  Proceed to unwrap the file system.
365 	 */
366 	mutex_exit(&pi_mtx);
367 
368 	/* hmm?  suspicious locking? */
369 	while ((rv = pi->pi_pop->pop_close(pi->pi_private)) == ERESTART)
370 		goto restart;
371 
372  out:
373 	KERNEL_UNLOCK_ONE(NULL);
374 	/*
375 	 * Finally, release the instance information.  It was already
376 	 * removed from the list by putter_rmprivate() and we know it's
377 	 * dead, so no need to lock.
378 	 */
379 	kmem_free(pi, sizeof(struct putter_instance));
380 
381 	return 0;
382 }
383 
384 static int
385 putter_fop_ioctl(file_t *fp, u_long cmd, void *data)
386 {
387 
388 	/*
389 	 * work already done in sys_ioctl().  skip sanity checks to enable
390 	 * setting non-blocking fd without yet having mounted the fs
391 	 */
392 	if (cmd == FIONBIO)
393 		return 0;
394 
395 	return EINVAL;
396 }
397 
398 /* kqueue stuff */
399 
400 static void
401 filt_putterdetach(struct knote *kn)
402 {
403 	struct putter_instance *pi = kn->kn_hook;
404 
405 	KERNEL_LOCK(1, NULL);
406 	mutex_enter(&pi_mtx);
407 	SLIST_REMOVE(&pi->pi_sel.sel_klist, kn, knote, kn_selnext);
408 	mutex_exit(&pi_mtx);
409 	KERNEL_UNLOCK_ONE(NULL);
410 }
411 
412 static int
413 filt_putter(struct knote *kn, long hint)
414 {
415 	struct putter_instance *pi = kn->kn_hook;
416 	int error, rv;
417 
418 	KERNEL_LOCK(1, NULL);
419 	error = 0;
420 	mutex_enter(&pi_mtx);
421 	if (pi->pi_private == PUTTER_EMBRYO || pi->pi_private == PUTTER_DEAD)
422 		error = 1;
423 	mutex_exit(&pi_mtx);
424 	if (error) {
425 		KERNEL_UNLOCK_ONE(NULL);
426 		return 0;
427 	}
428 
429 	kn->kn_data = pi->pi_pop->pop_waitcount(pi->pi_private);
430 	rv = kn->kn_data != 0;
431 	KERNEL_UNLOCK_ONE(NULL);
432 	return rv;
433 }
434 
435 static const struct filterops putter_filtops =
436 	{ 1, NULL, filt_putterdetach, filt_putter };
437 
438 static int
439 putter_fop_kqfilter(file_t *fp, struct knote *kn)
440 {
441 	struct putter_instance *pi = fp->f_data;
442 	struct klist *klist;
443 
444 	KERNEL_LOCK(1, NULL);
445 
446 	switch (kn->kn_filter) {
447 	case EVFILT_READ:
448 		klist = &pi->pi_sel.sel_klist;
449 		kn->kn_fop = &putter_filtops;
450 		kn->kn_hook = pi;
451 
452 		mutex_enter(&pi_mtx);
453 		SLIST_INSERT_HEAD(klist, kn, kn_selnext);
454 		mutex_exit(&pi_mtx);
455 
456 		break;
457 	case EVFILT_WRITE:
458 		kn->kn_fop = &seltrue_filtops;
459 		break;
460 	default:
461 		KERNEL_UNLOCK_ONE(NULL);
462 		return EINVAL;
463 	}
464 
465 	KERNEL_UNLOCK_ONE(NULL);
466 	return 0;
467 }
468 
469 /*
470  * Device routines.  These are for when /dev/puffs is initially
471  * opened before it has been cloned.
472  */
473 
474 dev_type_open(puttercdopen);
475 dev_type_close(puttercdclose);
476 dev_type_ioctl(puttercdioctl);
477 
478 /* dev */
479 const struct cdevsw putter_cdevsw = {
480 	puttercdopen,	puttercdclose,	noread,		nowrite,
481 	noioctl,	nostop,		notty,		nopoll,
482 	nommap,		nokqfilter,	D_OTHER
483 };
484 int
485 puttercdopen(dev_t dev, int flags, int fmt, struct lwp *l)
486 {
487 	struct putter_instance *pi;
488 	file_t *fp;
489 	int error, fd, idx;
490 	proc_t *p;
491 
492 	p = curproc;
493 	pi = kmem_alloc(sizeof(struct putter_instance), KM_SLEEP);
494 	mutex_enter(&pi_mtx);
495 	idx = get_pi_idx(pi);
496 
497 	pi->pi_pid = p->p_pid;
498 	pi->pi_idx = idx;
499 	pi->pi_curput = NULL;
500 	pi->pi_curres = 0;
501 	pi->pi_curopaq = NULL;
502 	selinit(&pi->pi_sel);
503 	mutex_exit(&pi_mtx);
504 
505 	if ((error = fd_allocfile(&fp, &fd)) != 0)
506 		goto bad1;
507 
508 	if ((error = putter_configure(dev, flags, fmt, fd)) != 0)
509 		goto bad2;
510 
511 	DPRINTF(("puttercdopen: registered embryonic pmp for pid: %d\n",
512 	    pi->pi_pid));
513 
514 	error = fd_clone(fp, fd, FREAD|FWRITE, &putter_fileops, pi);
515 	KASSERT(error == EMOVEFD);
516 	return error;
517 
518  bad2:
519  	fd_abort(p, fp, fd);
520  bad1:
521 	putter_detach(pi);
522 	kmem_free(pi, sizeof(struct putter_instance));
523 	return error;
524 }
525 
526 int
527 puttercdclose(dev_t dev, int flags, int fmt, struct lwp *l)
528 {
529 
530 	panic("puttercdclose impossible\n");
531 
532 	return 0;
533 }
534 
535 
536 /*
537  * Set the private structure for the file descriptor.  This is
538  * typically done immediately when the counterpart has knowledge
539  * about the private structure's address and the file descriptor
540  * (e.g. vfs mount routine).
541  *
542  * We only want to make sure that the caller had the right to open the
543  * device, we don't so much care about which context it gets in case
544  * the same process opened multiple (since they are equal at this point).
545  */
546 struct putter_instance *
547 putter_attach(pid_t pid, int fd, void *ppriv, struct putter_ops *pop)
548 {
549 	struct putter_instance *pi = NULL;
550 
551 	mutex_enter(&pi_mtx);
552 	TAILQ_FOREACH(pi, &putter_ilist, pi_entries) {
553 		if (pi->pi_pid == pid && pi->pi_private == PUTTER_EMBRYO) {
554 			pi->pi_private = ppriv;
555 			pi->pi_fd = fd;
556 			pi->pi_pop = pop;
557 			break;
558 		    }
559 	}
560 	mutex_exit(&pi_mtx);
561 
562 	DPRINTF(("putter_setprivate: pi at %p (%d/%d)\n", pi,
563 	    pi ? pi->pi_pid : 0, pi ? pi->pi_fd : 0));
564 
565 	return pi;
566 }
567 
568 /*
569  * Remove fp <-> private mapping.
570  */
571 void
572 putter_detach(struct putter_instance *pi)
573 {
574 
575 	mutex_enter(&pi_mtx);
576 	TAILQ_REMOVE(&putter_ilist, pi, pi_entries);
577 	pi->pi_private = PUTTER_DEAD;
578 	mutex_exit(&pi_mtx);
579 
580 	DPRINTF(("putter_nukebypmp: nuked %p\n", pi));
581 }
582 
583 void
584 putter_notify(struct putter_instance *pi)
585 {
586 
587 	selnotify(&pi->pi_sel, 0, 0);
588 }
589 
590 /* search sorted list of instances for free minor, sorted insert arg */
591 static int
592 get_pi_idx(struct putter_instance *pi_i)
593 {
594 	struct putter_instance *pi;
595 	int i;
596 
597 	KASSERT(mutex_owned(&pi_mtx));
598 
599 	i = 0;
600 	TAILQ_FOREACH(pi, &putter_ilist, pi_entries) {
601 		if (i != pi->pi_idx)
602 			break;
603 		i++;
604 	}
605 
606 	pi_i->pi_private = PUTTER_EMBRYO;
607 
608 	if (pi == NULL)
609 		TAILQ_INSERT_TAIL(&putter_ilist, pi_i, pi_entries);
610 	else
611 		TAILQ_INSERT_BEFORE(pi, pi_i, pi_entries);
612 
613 	return i;
614 }
615 
616 MODULE(MODULE_CLASS_MISC, putter, NULL);
617 
618 static int
619 putter_modcmd(modcmd_t cmd, void *arg)
620 {
621 #ifdef _MODULE
622 	int bmajor = -1, cmajor = -1;
623 
624 	switch (cmd) {
625 	case MODULE_CMD_INIT:
626 		return devsw_attach("putter", NULL, &bmajor,
627 		    &putter_cdevsw, &cmajor);
628 	case MODULE_CMD_FINI:
629 		return devsw_detach(NULL, &putter_cdevsw);
630 	default:
631 		return ENOTTY;
632 	}
633 #else
634 	if (cmd == MODULE_CMD_INIT)
635 		return 0;
636 	return ENOTTY;
637 #endif
638 }
639