freebsd-dev/sys/fs/fuse/fuse_device.c
Pedro F. Giffuni 51369649b0 sys: further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 3-Clause license.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.
2017-11-20 19:43:44 +00:00

449 lines
13 KiB
C

/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 2007-2009 Google Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* Copyright (C) 2005 Csaba Henk.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <sys/module.h>
#include <sys/systm.h>
#include <sys/errno.h>
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/conf.h>
#include <sys/uio.h>
#include <sys/malloc.h>
#include <sys/queue.h>
#include <sys/lock.h>
#include <sys/sx.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/fcntl.h>
#include <sys/sysctl.h>
#include <sys/poll.h>
#include <sys/selinfo.h>
#include "fuse.h"
#include "fuse_ipc.h"
#define FUSE_DEBUG_MODULE DEVICE
#include "fuse_debug.h"
static struct cdev *fuse_dev;
static d_open_t fuse_device_open;
static d_close_t fuse_device_close;
static d_poll_t fuse_device_poll;
static d_read_t fuse_device_read;
static d_write_t fuse_device_write;
static struct cdevsw fuse_device_cdevsw = {
.d_open = fuse_device_open,
.d_close = fuse_device_close,
.d_name = "fuse",
.d_poll = fuse_device_poll,
.d_read = fuse_device_read,
.d_write = fuse_device_write,
.d_version = D_VERSION,
};
/****************************
*
* >>> Fuse device op defs
*
****************************/
static void
fdata_dtor(void *arg)
{
struct fuse_data *fdata;
fdata = arg;
fdata_trydestroy(fdata);
}
/*
* Resources are set up on a per-open basis
*/
static int
fuse_device_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
{
struct fuse_data *fdata;
int error;
FS_DEBUG("device %p\n", dev);
fdata = fdata_alloc(dev, td->td_ucred);
error = devfs_set_cdevpriv(fdata, fdata_dtor);
if (error != 0)
fdata_trydestroy(fdata);
else
FS_DEBUG("%s: device opened by thread %d.\n", dev->si_name,
td->td_tid);
return (error);
}
static int
fuse_device_close(struct cdev *dev, int fflag, int devtype, struct thread *td)
{
struct fuse_data *data;
struct fuse_ticket *tick;
int error;
error = devfs_get_cdevpriv((void **)&data);
if (error != 0)
return (error);
if (!data)
panic("no fuse data upon fuse device close");
fdata_set_dead(data);
FUSE_LOCK();
fuse_lck_mtx_lock(data->aw_mtx);
/* wakup poll()ers */
selwakeuppri(&data->ks_rsel, PZERO + 1);
/* Don't let syscall handlers wait in vain */
while ((tick = fuse_aw_pop(data))) {
fuse_lck_mtx_lock(tick->tk_aw_mtx);
fticket_set_answered(tick);
tick->tk_aw_errno = ENOTCONN;
wakeup(tick);
fuse_lck_mtx_unlock(tick->tk_aw_mtx);
FUSE_ASSERT_AW_DONE(tick);
fuse_ticket_drop(tick);
}
fuse_lck_mtx_unlock(data->aw_mtx);
FUSE_UNLOCK();
FS_DEBUG("%s: device closed by thread %d.\n", dev->si_name, td->td_tid);
return (0);
}
int
fuse_device_poll(struct cdev *dev, int events, struct thread *td)
{
struct fuse_data *data;
int error, revents = 0;
error = devfs_get_cdevpriv((void **)&data);
if (error != 0)
return (events &
(POLLHUP|POLLIN|POLLRDNORM|POLLOUT|POLLWRNORM));
if (events & (POLLIN | POLLRDNORM)) {
fuse_lck_mtx_lock(data->ms_mtx);
if (fdata_get_dead(data) || STAILQ_FIRST(&data->ms_head))
revents |= events & (POLLIN | POLLRDNORM);
else
selrecord(td, &data->ks_rsel);
fuse_lck_mtx_unlock(data->ms_mtx);
}
if (events & (POLLOUT | POLLWRNORM)) {
revents |= events & (POLLOUT | POLLWRNORM);
}
return (revents);
}
/*
* fuse_device_read hangs on the queue of VFS messages.
* When it's notified that there is a new one, it picks that and
* passes up to the daemon
*/
int
fuse_device_read(struct cdev *dev, struct uio *uio, int ioflag)
{
int err;
struct fuse_data *data;
struct fuse_ticket *tick;
void *buf[] = {NULL, NULL, NULL};
int buflen[3];
int i;
FS_DEBUG("fuse device being read on thread %d\n", uio->uio_td->td_tid);
err = devfs_get_cdevpriv((void **)&data);
if (err != 0)
return (err);
fuse_lck_mtx_lock(data->ms_mtx);
again:
if (fdata_get_dead(data)) {
FS_DEBUG2G("we know early on that reader should be kicked so we don't wait for news\n");
fuse_lck_mtx_unlock(data->ms_mtx);
return (ENODEV);
}
if (!(tick = fuse_ms_pop(data))) {
/* check if we may block */
if (ioflag & O_NONBLOCK) {
/* get outa here soon */
fuse_lck_mtx_unlock(data->ms_mtx);
return (EAGAIN);
} else {
err = msleep(data, &data->ms_mtx, PCATCH, "fu_msg", 0);
if (err != 0) {
fuse_lck_mtx_unlock(data->ms_mtx);
return (fdata_get_dead(data) ? ENODEV : err);
}
tick = fuse_ms_pop(data);
}
}
if (!tick) {
/*
* We can get here if fuse daemon suddenly terminates,
* eg, by being hit by a SIGKILL
* -- and some other cases, too, tho not totally clear, when
* (cv_signal/wakeup_one signals the whole process ?)
*/
FS_DEBUG("no message on thread #%d\n", uio->uio_td->td_tid);
goto again;
}
fuse_lck_mtx_unlock(data->ms_mtx);
if (fdata_get_dead(data)) {
/*
* somebody somewhere -- eg., umount routine --
* wants this liaison finished off
*/
FS_DEBUG2G("reader is to be sacked\n");
if (tick) {
FS_DEBUG2G("weird -- \"kick\" is set tho there is message\n");
FUSE_ASSERT_MS_DONE(tick);
fuse_ticket_drop(tick);
}
return (ENODEV); /* This should make the daemon get off
* of us */
}
FS_DEBUG("message got on thread #%d\n", uio->uio_td->td_tid);
KASSERT(tick->tk_ms_bufdata || tick->tk_ms_bufsize == 0,
("non-null buf pointer with positive size"));
switch (tick->tk_ms_type) {
case FT_M_FIOV:
buf[0] = tick->tk_ms_fiov.base;
buflen[0] = tick->tk_ms_fiov.len;
break;
case FT_M_BUF:
buf[0] = tick->tk_ms_fiov.base;
buflen[0] = tick->tk_ms_fiov.len;
buf[1] = tick->tk_ms_bufdata;
buflen[1] = tick->tk_ms_bufsize;
break;
default:
panic("unknown message type for fuse_ticket %p", tick);
}
for (i = 0; buf[i]; i++) {
/*
* Why not ban mercilessly stupid daemons who can't keep up
* with us? (There is no much use of a partial read here...)
*/
/*
* XXX note that in such cases Linux FUSE throws EIO at the
* syscall invoker and stands back to the message queue. The
* rationale should be made clear (and possibly adopt that
* behaviour). Keeping the current scheme at least makes
* fallacy as loud as possible...
*/
if (uio->uio_resid < buflen[i]) {
fdata_set_dead(data);
FS_DEBUG2G("daemon is stupid, kick it off...\n");
err = ENODEV;
break;
}
err = uiomove(buf[i], buflen[i], uio);
if (err)
break;
}
FUSE_ASSERT_MS_DONE(tick);
fuse_ticket_drop(tick);
return (err);
}
static __inline int
fuse_ohead_audit(struct fuse_out_header *ohead, struct uio *uio)
{
FS_DEBUG("Out header -- len: %i, error: %i, unique: %llu; iovecs: %d\n",
ohead->len, ohead->error, (unsigned long long)ohead->unique,
uio->uio_iovcnt);
if (uio->uio_resid + sizeof(struct fuse_out_header) != ohead->len) {
FS_DEBUG("Format error: body size differs from size claimed by header\n");
return (EINVAL);
}
if (uio->uio_resid && ohead->error) {
FS_DEBUG("Format error: non zero error but message had a body\n");
return (EINVAL);
}
/* Sanitize the linuxism of negative errnos */
ohead->error = -(ohead->error);
return (0);
}
/*
* fuse_device_write first reads the header sent by the daemon.
* If that's OK, looks up ticket/callback node by the unique id seen in header.
* If the callback node contains a handler function, the uio is passed over
* that.
*/
static int
fuse_device_write(struct cdev *dev, struct uio *uio, int ioflag)
{
struct fuse_out_header ohead;
int err = 0;
struct fuse_data *data;
struct fuse_ticket *tick, *x_tick;
int found = 0;
FS_DEBUG("resid: %zd, iovcnt: %d, thread: %d\n",
uio->uio_resid, uio->uio_iovcnt, uio->uio_td->td_tid);
err = devfs_get_cdevpriv((void **)&data);
if (err != 0)
return (err);
if (uio->uio_resid < sizeof(struct fuse_out_header)) {
FS_DEBUG("got less than a header!\n");
fdata_set_dead(data);
return (EINVAL);
}
if ((err = uiomove(&ohead, sizeof(struct fuse_out_header), uio)) != 0)
return (err);
/*
* We check header information (which is redundant) and compare it
* with what we see. If we see some inconsistency we discard the
* whole answer and proceed on as if it had never existed. In
* particular, no pretender will be woken up, regardless the
* "unique" value in the header.
*/
if ((err = fuse_ohead_audit(&ohead, uio))) {
fdata_set_dead(data);
return (err);
}
/* Pass stuff over to callback if there is one installed */
/* Looking for ticket with the unique id of header */
fuse_lck_mtx_lock(data->aw_mtx);
TAILQ_FOREACH_SAFE(tick, &data->aw_head, tk_aw_link,
x_tick) {
FS_DEBUG("bumped into callback #%llu\n",
(unsigned long long)tick->tk_unique);
if (tick->tk_unique == ohead.unique) {
found = 1;
fuse_aw_remove(tick);
break;
}
}
fuse_lck_mtx_unlock(data->aw_mtx);
if (found) {
if (tick->tk_aw_handler) {
/*
* We found a callback with proper handler. In this
* case the out header will be 0wnd by the callback,
* so the fun of freeing that is left for her.
* (Then, by all chance, she'll just get that's done
* via ticket_drop(), so no manual mucking
* around...)
*/
FS_DEBUG("pass ticket to a callback\n");
memcpy(&tick->tk_aw_ohead, &ohead, sizeof(ohead));
err = tick->tk_aw_handler(tick, uio);
} else {
/* pretender doesn't wanna do anything with answer */
FS_DEBUG("stuff devalidated, so we drop it\n");
}
/*
* As aw_mtx was not held during the callback execution the
* ticket may have been inserted again. However, this is safe
* because fuse_ticket_drop() will deal with refcount anyway.
*/
fuse_ticket_drop(tick);
} else {
/* no callback at all! */
FS_DEBUG("erhm, no handler for this response\n");
err = EINVAL;
}
return (err);
}
int
fuse_device_init(void)
{
fuse_dev = make_dev(&fuse_device_cdevsw, 0, UID_ROOT, GID_OPERATOR,
S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP, "fuse");
if (fuse_dev == NULL)
return (ENOMEM);
return (0);
}
void
fuse_device_destroy(void)
{
MPASS(fuse_dev != NULL);
destroy_dev(fuse_dev);
}