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puffs.c revision 1.74 
      1 /*	$NetBSD: puffs.c,v 1.74 2007/11/06 15:09:08 pooka Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 2005, 2006, 2007  Antti Kantee.  All Rights Reserved.
      5  *
      6  * Development of this software was supported by the
      7  * Google Summer of Code program and the Ulla Tuominen Foundation.
      8  * The Google SoC project was mentored by Bill Studenmund.
      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 #include <sys/cdefs.h>
     33 #if !defined(lint)
     34 __RCSID("$NetBSD: puffs.c,v 1.74 2007/11/06 15:09:08 pooka Exp $");
     35 #endif /* !lint */
     36 
     37 #include <sys/param.h>
     38 #include <sys/mount.h>
     39 
     40 #include <assert.h>
     41 #include <err.h>
     42 #include <errno.h>
     43 #include <fcntl.h>
     44 #include <mntopts.h>
     45 #include <paths.h>
     46 #include <puffs.h>
     47 #include <stdio.h>
     48 #include <stdlib.h>
     49 #include <string.h>
     50 #include <syslog.h>
     51 #include <unistd.h>
     52 
     53 #include "puffs_priv.h"
     54 
     55 /* Most file systems want this for opts, so just give it to them */
     56 const struct mntopt puffsmopts[] = {
     57 	MOPT_STDOPTS,
     58 	PUFFSMOPT_STD,
     59 	MOPT_NULL,
     60 };
     61 
     62 #ifdef PUFFS_WITH_THREADS
     63 #include <pthread.h>
     64 pthread_mutex_t pu_lock = PTHREAD_MUTEX_INITIALIZER;
     65 #endif
     66 
     67 #define FILLOP(lower, upper)						\
     68 do {									\
     69 	if (pops->puffs_node_##lower)					\
     70 		opmask[PUFFS_VN_##upper] = 1;				\
     71 } while (/*CONSTCOND*/0)
     72 static void
     73 fillvnopmask(struct puffs_ops *pops, uint8_t *opmask)
     74 {
     75 
     76 	memset(opmask, 0, PUFFS_VN_MAX);
     77 
     78 	FILLOP(create,   CREATE);
     79 	FILLOP(mknod,    MKNOD);
     80 	FILLOP(open,     OPEN);
     81 	FILLOP(close,    CLOSE);
     82 	FILLOP(access,   ACCESS);
     83 	FILLOP(getattr,  GETATTR);
     84 	FILLOP(setattr,  SETATTR);
     85 	FILLOP(poll,     POLL); /* XXX: not ready in kernel */
     86 	FILLOP(mmap,     MMAP);
     87 	FILLOP(fsync,    FSYNC);
     88 	FILLOP(seek,     SEEK);
     89 	FILLOP(remove,   REMOVE);
     90 	FILLOP(link,     LINK);
     91 	FILLOP(rename,   RENAME);
     92 	FILLOP(mkdir,    MKDIR);
     93 	FILLOP(rmdir,    RMDIR);
     94 	FILLOP(symlink,  SYMLINK);
     95 	FILLOP(readdir,  READDIR);
     96 	FILLOP(readlink, READLINK);
     97 	FILLOP(reclaim,  RECLAIM);
     98 	FILLOP(inactive, INACTIVE);
     99 	FILLOP(print,    PRINT);
    100 	FILLOP(read,     READ);
    101 	FILLOP(write,    WRITE);
    102 }
    103 #undef FILLOP
    104 
    105 /*ARGSUSED*/
    106 static void
    107 puffs_defaulterror(struct puffs_usermount *pu, uint8_t type,
    108 	int error, const char *str, void *cookie)
    109 {
    110 
    111 	fprintf(stderr, "%s\n", str);
    112 	abort();
    113 }
    114 
    115 int
    116 puffs_getselectable(struct puffs_usermount *pu)
    117 {
    118 
    119 	return pu->pu_fd;
    120 }
    121 
    122 int
    123 puffs_setblockingmode(struct puffs_usermount *pu, int mode)
    124 {
    125 	int rv, x;
    126 
    127 	assert(puffs_getstate(pu) == PUFFS_STATE_RUNNING);
    128 
    129 	if (mode != PUFFSDEV_BLOCK && mode != PUFFSDEV_NONBLOCK) {
    130 		errno = EINVAL;
    131 		return -1;
    132 	}
    133 
    134 	x = mode;
    135 	rv = ioctl(pu->pu_fd, FIONBIO, &x);
    136 
    137 	if (rv == 0) {
    138 		if (mode == PUFFSDEV_BLOCK)
    139 			pu->pu_state &= ~PU_ASYNCFD;
    140 		else
    141 			pu->pu_state |= PU_ASYNCFD;
    142 	}
    143 
    144 	return rv;
    145 }
    146 
    147 int
    148 puffs_getstate(struct puffs_usermount *pu)
    149 {
    150 
    151 	return pu->pu_state & PU_STATEMASK;
    152 }
    153 
    154 void
    155 puffs_setstacksize(struct puffs_usermount *pu, size_t ss)
    156 {
    157 	int stackshift;
    158 
    159 	assert(puffs_getstate(pu) == PUFFS_STATE_BEFOREMOUNT);
    160 	stackshift = -1;
    161 	while (ss) {
    162 		ss >>= 1;
    163 		stackshift++;
    164 	}
    165 	pu->pu_cc_stackshift = stackshift;
    166 	assert(1<<stackshift == ss);
    167 }
    168 
    169 struct puffs_pathobj *
    170 puffs_getrootpathobj(struct puffs_usermount *pu)
    171 {
    172 	struct puffs_node *pnr;
    173 
    174 	pnr = pu->pu_pn_root;
    175 	if (pnr == NULL) {
    176 		errno = ENOENT;
    177 		return NULL;
    178 	}
    179 
    180 	return &pnr->pn_po;
    181 }
    182 
    183 void
    184 puffs_setroot(struct puffs_usermount *pu, struct puffs_node *pn)
    185 {
    186 
    187 	pu->pu_pn_root = pn;
    188 }
    189 
    190 struct puffs_node *
    191 puffs_getroot(struct puffs_usermount *pu)
    192 {
    193 
    194 	return pu->pu_pn_root;
    195 }
    196 
    197 void
    198 puffs_setrootinfo(struct puffs_usermount *pu, enum vtype vt,
    199 	vsize_t vsize, dev_t rdev)
    200 {
    201 	struct puffs_kargs *pargs = pu->pu_kargp;
    202 
    203 	if (puffs_getstate(pu) != PUFFS_STATE_BEFOREMOUNT) {
    204 		warnx("puffs_setrootinfo: call has effect only "
    205 		    "before mount\n");
    206 		return;
    207 	}
    208 
    209 	pargs->pa_root_vtype = vt;
    210 	pargs->pa_root_vsize = vsize;
    211 	pargs->pa_root_rdev = rdev;
    212 }
    213 
    214 void *
    215 puffs_getspecific(struct puffs_usermount *pu)
    216 {
    217 
    218 	return pu->pu_privdata;
    219 }
    220 
    221 size_t
    222 puffs_getmaxreqlen(struct puffs_usermount *pu)
    223 {
    224 
    225 	return pu->pu_maxreqlen;
    226 }
    227 
    228 void
    229 puffs_setmaxreqlen(struct puffs_usermount *pu, size_t reqlen)
    230 {
    231 
    232 	if (puffs_getstate(pu) != PUFFS_STATE_BEFOREMOUNT)
    233 		warnx("puffs_setmaxreqlen: call has effect only "
    234 		    "before mount\n");
    235 
    236 	pu->pu_kargp->pa_maxmsglen = reqlen;
    237 }
    238 
    239 void
    240 puffs_setfhsize(struct puffs_usermount *pu, size_t fhsize, int flags)
    241 {
    242 
    243 	if (puffs_getstate(pu) != PUFFS_STATE_BEFOREMOUNT)
    244 		warnx("puffs_setfhsize: call has effect only before mount\n");
    245 
    246 	pu->pu_kargp->pa_fhsize = fhsize;
    247 	pu->pu_kargp->pa_fhflags = flags;
    248 }
    249 
    250 void
    251 puffs_setncookiehash(struct puffs_usermount *pu, int nhash)
    252 {
    253 
    254 	if (puffs_getstate(pu) != PUFFS_STATE_BEFOREMOUNT)
    255 		warnx("puffs_setfhsize: call has effect only before mount\n");
    256 
    257 	pu->pu_kargp->pa_nhashbuckets = nhash;
    258 }
    259 
    260 void
    261 puffs_set_pathbuild(struct puffs_usermount *pu, pu_pathbuild_fn fn)
    262 {
    263 
    264 	pu->pu_pathbuild = fn;
    265 }
    266 
    267 void
    268 puffs_set_pathtransform(struct puffs_usermount *pu, pu_pathtransform_fn fn)
    269 {
    270 
    271 	pu->pu_pathtransform = fn;
    272 }
    273 
    274 void
    275 puffs_set_pathcmp(struct puffs_usermount *pu, pu_pathcmp_fn fn)
    276 {
    277 
    278 	pu->pu_pathcmp = fn;
    279 }
    280 
    281 void
    282 puffs_set_pathfree(struct puffs_usermount *pu, pu_pathfree_fn fn)
    283 {
    284 
    285 	pu->pu_pathfree = fn;
    286 }
    287 
    288 void
    289 puffs_set_namemod(struct puffs_usermount *pu, pu_namemod_fn fn)
    290 {
    291 
    292 	pu->pu_namemod = fn;
    293 }
    294 
    295 void
    296 puffs_set_errnotify(struct puffs_usermount *pu, pu_errnotify_fn fn)
    297 {
    298 
    299 	pu->pu_errnotify = fn;
    300 }
    301 
    302 void
    303 puffs_ml_setloopfn(struct puffs_usermount *pu, puffs_ml_loop_fn lfn)
    304 {
    305 
    306 	pu->pu_ml_lfn = lfn;
    307 }
    308 
    309 void
    310 puffs_ml_settimeout(struct puffs_usermount *pu, struct timespec *ts)
    311 {
    312 
    313 	if (ts == NULL) {
    314 		pu->pu_ml_timep = NULL;
    315 	} else {
    316 		pu->pu_ml_timeout = *ts;
    317 		pu->pu_ml_timep = &pu->pu_ml_timeout;
    318 	}
    319 }
    320 
    321 void
    322 puffs_set_prepost(struct puffs_usermount *pu,
    323 	pu_prepost_fn pre, pu_prepost_fn pst)
    324 {
    325 
    326 	pu->pu_oppre = pre;
    327 	pu->pu_oppost = pst;
    328 }
    329 
    330 void
    331 puffs_setback(struct puffs_cc *pcc, int whatback)
    332 {
    333 	struct puffs_req *preq = pcc->pcc_preq;
    334 
    335 	assert(PUFFSOP_OPCLASS(preq->preq_opclass) == PUFFSOP_VN && (
    336 	    preq->preq_optype == PUFFS_VN_OPEN ||
    337 	    preq->preq_optype == PUFFS_VN_MMAP ||
    338 	    preq->preq_optype == PUFFS_VN_REMOVE ||
    339 	    preq->preq_optype == PUFFS_VN_RMDIR ||
    340 	    preq->preq_optype == PUFFS_VN_INACTIVE));
    341 
    342 	preq->preq_setbacks |= whatback & PUFFS_SETBACK_MASK;
    343 }
    344 
    345 int
    346 puffs_mount(struct puffs_usermount *pu, const char *dir, int mntflags,
    347 	void *cookie)
    348 {
    349 	char rp[MAXPATHLEN];
    350 	int rv, fd;
    351 
    352 #if 1
    353 	/* XXXkludgehere */
    354 	/* kauth doesn't provide this service any longer */
    355 	if (geteuid() != 0)
    356 		mntflags |= MNT_NOSUID | MNT_NODEV;
    357 #endif
    358 
    359 	if (realpath(dir, rp) == NULL)
    360 		return -1;
    361 
    362 	if (strcmp(dir, rp) != 0) {
    363 		warnx("puffs_mount: \"%s\" is a relative path.", dir);
    364 		warnx("puffs_mount: using \"%s\" instead.", rp);
    365 	}
    366 
    367 	fd = open(_PATH_PUFFS, O_RDONLY);
    368 	if (fd == -1) {
    369 		warnx("puffs_mount: cannot open %s", _PATH_PUFFS);
    370 		return -1;
    371 	}
    372 	if (fd <= 2)
    373 		warnx("puffs_init: device fd %d (<= 2), sure this is "
    374 		    "what you want?", fd);
    375 
    376 	pu->pu_kargp->pa_fd = pu->pu_fd = fd;
    377 	pu->pu_kargp->pa_root_cookie = cookie;
    378 	if ((rv = mount(MOUNT_PUFFS, rp, mntflags,
    379 	    pu->pu_kargp, sizeof(struct puffs_kargs))) == -1)
    380 		goto out;
    381 #if 0
    382 	if ((rv = ioctl(pu->pu_fd, PUFFSREQSIZEOP, &pu->pu_maxreqlen)) == -1)
    383 		goto out;
    384 #endif
    385 	PU_SETSTATE(pu, PUFFS_STATE_RUNNING);
    386 
    387  out:
    388 	free(pu->pu_kargp);
    389 	pu->pu_kargp = NULL;
    390 
    391 	return rv;
    392 }
    393 
    394 struct puffs_usermount *
    395 _puffs_init(int develv, struct puffs_ops *pops, const char *mntfromname,
    396 	const char *puffsname, void *priv, uint32_t pflags)
    397 {
    398 	struct puffs_usermount *pu;
    399 	struct puffs_kargs *pargs;
    400 	int sverrno;
    401 
    402 	if (develv != PUFFS_DEVEL_LIBVERSION) {
    403 		warnx("puffs_init: mounting with lib version %d, need %d",
    404 		    develv, PUFFS_DEVEL_LIBVERSION);
    405 		errno = EINVAL;
    406 		return NULL;
    407 	}
    408 
    409 	pu = malloc(sizeof(struct puffs_usermount));
    410 	if (pu == NULL)
    411 		goto failfree;
    412 	memset(pu, 0, sizeof(struct puffs_usermount));
    413 
    414 	pargs = pu->pu_kargp = malloc(sizeof(struct puffs_kargs));
    415 	if (pargs == NULL)
    416 		goto failfree;
    417 	memset(pargs, 0, sizeof(struct puffs_kargs));
    418 
    419 	pargs->pa_vers = PUFFSDEVELVERS | PUFFSVERSION;
    420 	pargs->pa_flags = PUFFS_FLAG_KERN(pflags);
    421 	fillvnopmask(pops, pargs->pa_vnopmask);
    422 	(void)strlcpy(pargs->pa_typename, puffsname,
    423 	    sizeof(pargs->pa_typename));
    424 	(void)strlcpy(pargs->pa_mntfromname, mntfromname,
    425 	    sizeof(pargs->pa_mntfromname));
    426 
    427 	puffs_zerostatvfs(&pargs->pa_svfsb);
    428 	pargs->pa_root_cookie = NULL;
    429 	pargs->pa_root_vtype = VDIR;
    430 	pargs->pa_root_vsize = 0;
    431 	pargs->pa_root_rdev = 0;
    432 	pargs->pa_maxmsglen = 0;
    433 
    434 	pu->pu_flags = pflags;
    435 	pu->pu_ops = *pops;
    436 	free(pops); /* XXX */
    437 
    438 	pu->pu_privdata = priv;
    439 	pu->pu_cc_stackshift = PUFFS_CC_STACKSHIFT_DEFAULT;
    440 	LIST_INIT(&pu->pu_pnodelst);
    441 	LIST_INIT(&pu->pu_framectrl.fb_ios);
    442 	LIST_INIT(&pu->pu_ccnukelst);
    443 	TAILQ_INIT(&pu->pu_sched);
    444 	TAILQ_INIT(&pu->pu_exq);
    445 
    446 	/* defaults for some user-settable translation functions */
    447 	pu->pu_cmap = NULL; /* identity translation */
    448 
    449 	pu->pu_pathbuild = puffs_stdpath_buildpath;
    450 	pu->pu_pathfree = puffs_stdpath_freepath;
    451 	pu->pu_pathcmp = puffs_stdpath_cmppath;
    452 	pu->pu_pathtransform = NULL;
    453 	pu->pu_namemod = NULL;
    454 
    455 	pu->pu_errnotify = puffs_defaulterror;
    456 
    457 	PU_SETSTATE(pu, PUFFS_STATE_BEFOREMOUNT);
    458 
    459 	return pu;
    460 
    461  failfree:
    462 	/* can't unmount() from here for obvious reasons */
    463 	sverrno = errno;
    464 	free(pu);
    465 	errno = sverrno;
    466 	return NULL;
    467 }
    468 
    469 /*
    470  * XXX: there's currently no clean way to request unmount from
    471  * within the user server, so be very brutal about it.
    472  */
    473 /*ARGSUSED1*/
    474 int
    475 puffs_exit(struct puffs_usermount *pu, int force)
    476 {
    477 	struct puffs_node *pn;
    478 
    479 	force = 1; /* currently */
    480 
    481 	if (pu->pu_fd)
    482 		close(pu->pu_fd);
    483 
    484 	while ((pn = LIST_FIRST(&pu->pu_pnodelst)) != NULL)
    485 		puffs_pn_put(pn);
    486 
    487 	puffs_framev_exit(pu);
    488 	if (pu->pu_state & PU_HASKQ)
    489 		close(pu->pu_kq);
    490 	free(pu);
    491 
    492 	return 0; /* always succesful for now, WILL CHANGE */
    493 }
    494 
    495 int
    496 puffs_mainloop(struct puffs_usermount *pu)
    497 {
    498 	struct puffs_getreq *pgr = NULL;
    499 	struct puffs_putreq *ppr = NULL;
    500 	struct puffs_framectrl *pfctrl = &pu->pu_framectrl;
    501 	struct puffs_fctrl_io *fio;
    502 	struct puffs_cc *pcc;
    503 	struct kevent *curev, *newevs;
    504 	size_t nchanges;
    505 	int puffsfd, sverrno;
    506 	int ndone;
    507 
    508 	assert(puffs_getstate(pu) >= PUFFS_STATE_RUNNING);
    509 
    510 	pgr = puffs_req_makeget(pu, puffs_getmaxreqlen(pu), 0);
    511 	if (pgr == NULL)
    512 		goto out;
    513 
    514 	ppr = puffs_req_makeput(pu);
    515 	if (ppr == NULL)
    516 		goto out;
    517 
    518 	newevs = realloc(pfctrl->evs, (2*pfctrl->nfds+1)*sizeof(struct kevent));
    519 	if (newevs == NULL)
    520 		goto out;
    521 	pfctrl->evs = newevs;
    522 
    523 	pu->pu_state |= PU_INLOOP;
    524 
    525 	pu->pu_kq = kqueue();
    526 	if (pu->pu_kq == -1)
    527 		goto out;
    528 	pu->pu_state |= PU_HASKQ;
    529 
    530 	curev = pfctrl->evs;
    531 	LIST_FOREACH(fio, &pfctrl->fb_ios, fio_entries) {
    532 		EV_SET(curev, fio->io_fd, EVFILT_READ, EV_ADD,
    533 		    0, 0, (uintptr_t)fio);
    534 		curev++;
    535 		EV_SET(curev, fio->io_fd, EVFILT_WRITE, EV_ADD | EV_DISABLE,
    536 		    0, 0, (uintptr_t)fio);
    537 		curev++;
    538 	}
    539 	puffsfd = puffs_getselectable(pu);
    540 	EV_SET(curev, puffsfd, EVFILT_READ, EV_ADD, 0, 0, 0);
    541 	if (kevent(pu->pu_kq, pfctrl->evs, 2*pfctrl->nfds+1,
    542 	    NULL, 0, NULL) == -1)
    543 		goto out;
    544 
    545 	while (puffs_getstate(pu) != PUFFS_STATE_UNMOUNTED) {
    546 		if (pu->pu_ml_lfn)
    547 			pu->pu_ml_lfn(pu);
    548 
    549 		/*
    550 		 * Do this here, because:
    551 		 *  a) loopfunc might generate some results
    552 		 *  b) it's still "after" event handling (except for round 1)
    553 		 */
    554 		if (puffs_req_putput(ppr) == -1)
    555 			goto out;
    556 		puffs_req_resetput(ppr);
    557 
    558 		/* micro optimization: skip kevent syscall if possible */
    559 		if (pfctrl->nfds == 0 && pu->pu_ml_timep == NULL
    560 		    && (pu->pu_state & PU_ASYNCFD) == 0) {
    561 			if (puffs_req_handle(pgr, ppr, 0) == -1)
    562 				goto out;
    563 			continue;
    564 		}
    565 
    566 		/* else: do full processing */
    567 
    568 		/*
    569 		 * Build list of which to enable/disable in writecheck.
    570 		 * Don't bother worrying about O(n) for now.
    571 		 */
    572 		nchanges = 0;
    573 		LIST_FOREACH(fio, &pfctrl->fb_ios, fio_entries) {
    574 			if (fio->stat & FIO_WRGONE)
    575 				continue;
    576 
    577 			/*
    578 			 * Try to write out everything to avoid the
    579 			 * need for enabling EVFILT_WRITE.  The likely
    580 			 * case is that we can fit everything into the
    581 			 * socket buffer.
    582 			 */
    583 			if (puffs_framev_output(pu, pfctrl, fio, ppr)) {
    584 				/* need kernel notify? (error condition) */
    585 				if (puffs_req_putput(ppr) == -1)
    586 					goto out;
    587 				puffs_req_resetput(ppr);
    588 			}
    589 
    590 			/* en/disable write checks for kqueue as needed */
    591 			assert((FIO_EN_WRITE(fio) && FIO_RM_WRITE(fio)) == 0);
    592 			if (FIO_EN_WRITE(fio)) {
    593 				EV_SET(&pfctrl->evs[nchanges], fio->io_fd,
    594 				    EVFILT_WRITE, EV_ENABLE, 0, 0,
    595 				    (uintptr_t)fio);
    596 				fio->stat |= FIO_WR;
    597 				nchanges++;
    598 			}
    599 			if (FIO_RM_WRITE(fio)) {
    600 				EV_SET(&pfctrl->evs[nchanges], fio->io_fd,
    601 				    EVFILT_WRITE, EV_DISABLE, 0, 0,
    602 				    (uintptr_t)fio);
    603 				fio->stat &= ~FIO_WR;
    604 				nchanges++;
    605 			}
    606 			assert(nchanges <= pfctrl->nfds);
    607 		}
    608 
    609 		ndone = kevent(pu->pu_kq, pfctrl->evs, nchanges,
    610 		    pfctrl->evs, pfctrl->nfds+1, pu->pu_ml_timep);
    611 
    612 		if (ndone == -1) {
    613 			if (errno != EINTR)
    614 				goto out;
    615 			else
    616 				continue;
    617 		}
    618 
    619 		/* uoptimize */
    620 		if (ndone == 0)
    621 			continue;
    622 
    623 		/* iterate over the results */
    624 		for (curev = pfctrl->evs; ndone--; curev++) {
    625 			int what;
    626 
    627 			/* get & possibly dispatch events from kernel */
    628 			if (curev->ident == puffsfd) {
    629 				if (puffs_req_handle(pgr, ppr, 0) == -1)
    630 					goto out;
    631 				continue;
    632 			}
    633 
    634 			fio = (void *)curev->udata;
    635 			if (curev->flags & EV_ERROR) {
    636 				assert(curev->filter == EVFILT_WRITE);
    637 				fio->stat &= ~FIO_WR;
    638 
    639 				/* XXX: how to know if it's a transient error */
    640 				puffs_framev_writeclose(pu, fio,
    641 				    (int)curev->data);
    642 				puffs_framev_notify(fio, PUFFS_FBIO_ERROR);
    643 				continue;
    644 			}
    645 
    646 			what = 0;
    647 			if (curev->filter == EVFILT_READ) {
    648 				puffs_framev_input(pu, pfctrl, fio, ppr);
    649 				what |= PUFFS_FBIO_READ;
    650 			}
    651 
    652 			else if (curev->filter == EVFILT_WRITE) {
    653 				puffs_framev_output(pu, pfctrl, fio, ppr);
    654 				what |= PUFFS_FBIO_WRITE;
    655 			}
    656 			if (what)
    657 				puffs_framev_notify(fio, what);
    658 		}
    659 
    660 		/*
    661 		 * Schedule continuations.
    662 		 */
    663 		while ((pcc = TAILQ_FIRST(&pu->pu_sched)) != NULL) {
    664 			TAILQ_REMOVE(&pu->pu_sched, pcc, entries);
    665 			puffs_goto(pcc);
    666 		}
    667 
    668 		/*
    669 		 * Really free fd's now that we don't have references
    670 		 * to them.
    671 		 */
    672 		while ((fio = LIST_FIRST(&pfctrl->fb_ios_rmlist)) != NULL) {
    673 			LIST_REMOVE(fio, fio_entries);
    674 			free(fio);
    675 		}
    676 	}
    677 	errno = 0;
    678 	puffs_req_putput(ppr);
    679 
    680  out:
    681 	/* store the real error for a while */
    682 	sverrno = errno;
    683 
    684 	if (ppr)
    685 		puffs_req_destroyput(ppr);
    686 	if (pgr)
    687 		puffs_req_destroyget(pgr);
    688 
    689 	errno = sverrno;
    690 	if (errno)
    691 		return -1;
    692 	else
    693 		return 0;
    694 }
    695