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fuse_device.c
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fuse_device.c
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/*
* Copyright (C) 2006-2008 Google. All Rights Reserved.
* Copyright (C) 2011 Anatol Pomozov. All Rights Reserved.
*/
#include "fuse.h"
#include "fuse_device.h"
#include "fuse_ipc.h"
#include "fuse_internal.h"
#include "fuse_kernel.h"
#include "fuse_locking.h"
#include "fuse_sysctl.h"
#include <libkern/libkern.h>
#include <stdbool.h>
#include <sys/queue.h>
static int fuse_cdev_major = -1;
static bool fuse_interface_available = false;
static struct fuse_device fuse_device_table[FUSE4X_NDEVICES];
#define FUSE_DEVICE_FROM_UNIT_FAST(u) (fuse_device_t)&(fuse_device_table[(u)])
/* Interface for VFS */
/* Doesn't need lock. */
fuse_device_t
fuse_device_get(dev_t dev)
{
int unit = minor(dev);
if ((unit < 0) || (unit >= FUSE4X_NDEVICES)) {
return NULL;
}
return FUSE_DEVICE_FROM_UNIT_FAST(unit);
}
/* Must be called under lock. */
__inline__
void
fuse_device_close_final(fuse_device_t fdev)
{
fuse_data_destroy(fdev->data);
fdev->data = NULL;
fdev->pid = -1;
}
static __inline__
void
fuse_reject_answers(struct fuse_data *data)
{
struct fuse_ticket *ticket;
fuse_lck_mtx_lock(data->aw_mtx);
TAILQ_FOREACH(ticket, &data->aw_head, aw_link) {
fuse_lck_mtx_lock(ticket->aw_mtx);
ticket->answered = true;
ticket->aw_errno = ENOTCONN;
fuse_wakeup(ticket);
fuse_lck_mtx_unlock(ticket->aw_mtx);
}
TAILQ_INIT(&data->aw_head); // Remove all tickets from the queue
fuse_lck_mtx_unlock(data->aw_mtx);
}
/* /dev/fuse4xN implementation */
d_open_t fuse_device_open;
d_close_t fuse_device_close;
d_read_t fuse_device_read;
d_write_t fuse_device_write;
static struct cdevsw fuse_device_cdevsw = {
/* open */ fuse_device_open,
/* close */ fuse_device_close,
/* read */ fuse_device_read,
/* write */ fuse_device_write,
/* ioctl */ eno_ioctl,
/* stop */ eno_stop,
/* reset */ eno_reset,
/* ttys */ NULL,
/* select */ eno_select,
/* mmap */ eno_mmap,
/* strategy */ eno_strat,
/* getc */ eno_getc,
/* putc */ eno_putc,
/* flags */ D_TTY,
};
int
fuse_device_open(dev_t dev, __unused int flags, __unused int devtype,
struct proc *p)
{
int unit;
struct fuse_device *fdev;
struct fuse_data *data;
fuse_trace_printf_func();
if (!fuse_interface_available) {
return ENOENT;
}
unit = minor(dev);
if ((unit >= FUSE4X_NDEVICES) || (unit < 0)) {
fuse_lck_mtx_unlock(fuse_device_mutex);
return ENOENT;
}
fdev = FUSE_DEVICE_FROM_UNIT_FAST(unit);
if (!fdev) {
fuse_lck_mtx_unlock(fuse_device_mutex);
log("fuse4x: device found with no softc\n");
return ENXIO;
}
fuse_lck_mtx_lock(fuse_device_mutex);
if (fdev->usecount != 0) {
fuse_lck_mtx_unlock(fuse_device_mutex);
return EBUSY;
}
fdev->usecount++;
fuse_lck_mtx_lock(fdev->mtx);
fuse_lck_mtx_unlock(fuse_device_mutex);
/* Could block. */
data = fuse_data_alloc(p);
if (fdev->data) {
/*
* This slot isn't currently open by a user daemon. However, it was
* used earlier for a mount that's still lingering, even though the
* user daemon is dead.
*/
fuse_lck_mtx_lock(fuse_device_mutex);
fdev->usecount--;
fuse_lck_mtx_unlock(fdev->mtx);
fuse_lck_mtx_unlock(fuse_device_mutex);
fuse_data_destroy(data);
return EBUSY;
} else {
data->opened = true;
data->fdev = fdev;
fdev->data = data;
fdev->pid = proc_pid(p);
}
fuse_lck_mtx_unlock(fdev->mtx);
return KERN_SUCCESS;
}
int
fuse_device_close(dev_t dev, __unused int flags, __unused int devtype,
__unused struct proc *p)
{
int unit;
struct fuse_device *fdev;
struct fuse_data *data;
fuse_trace_printf_func();
unit = minor(dev);
if (unit >= FUSE4X_NDEVICES) {
return ENOENT;
}
fdev = FUSE_DEVICE_FROM_UNIT_FAST(unit);
if (!fdev) {
return ENXIO;
}
data = fdev->data;
if (!data) {
panic("fuse4x: no device private data in device_close");
}
fuse_data_kill(data);
fuse_lck_mtx_lock(fdev->mtx);
data->opened = false;
fuse_reject_answers(data);
if (!data->mounted) {
/* We're not mounted. Can destroy mpdata. */
fuse_device_close_final(fdev);
}
fuse_lck_mtx_unlock(fdev->mtx);
fuse_lck_mtx_lock(fuse_device_mutex);
/*
* Even if usecount goes 0 here, at open time, we check if fdev->data
* is non-NULL (that is, a lingering mount). If so, we return EBUSY.
* We could make the usecount depend on both device-use and mount-state,
* but I think this is truer to reality, if a bit more complex to maintain.
*/
fdev->usecount--;
fuse_lck_mtx_unlock(fuse_device_mutex);
return KERN_SUCCESS;
}
int
fuse_device_read(dev_t dev, uio_t uio, int ioflag)
{
int i, err = 0;
size_t buflen[3];
void *buf[] = { NULL, NULL, NULL };
struct fuse_device *fdev;
struct fuse_data *data;
struct fuse_ticket *ticket;
fuse_trace_printf_func();
fdev = FUSE_DEVICE_FROM_UNIT_FAST(minor(dev));
if (!fdev) {
return ENXIO;
}
data = fdev->data;
fuse_lck_mtx_lock(data->ms_mtx);
/* The read loop (outgoing messages to the user daemon). */
again:
if (data->dead) {
fuse_lck_mtx_unlock(data->ms_mtx);
return ENODEV;
}
if ((ticket = STAILQ_FIRST(&data->ms_head))) {
STAILQ_REMOVE_HEAD(&data->ms_head, ms_link);
} else {
if (ioflag & IO_NDELAY) {
fuse_lck_mtx_unlock(data->ms_mtx);
return EAGAIN;
}
err = fuse_msleep(data, data->ms_mtx, PCATCH, "fu_msg", NULL);
if (err) {
fuse_lck_mtx_unlock(data->ms_mtx);
return (data->dead ? ENODEV : err);
}
goto again;
}
fuse_lck_mtx_unlock(data->ms_mtx);
if (data->dead) {
if (ticket) {
fuse_ticket_drop_invalid(ticket);
}
return ENODEV;
}
switch (ticket->ms_type) {
case FT_M_FIOV:
buf[0] = ticket->ms_fiov.base;
buflen[0] = ticket->ms_fiov.len;
break;
case FT_M_BUF:
buf[0] = ticket->ms_fiov.base;
buflen[0] = ticket->ms_fiov.len;
buf[1] = ticket->ms_bufdata;
buflen[1] = ticket->ms_bufsize;
break;
default:
panic("fuse4x: unknown message type for ticket %p", ticket);
}
for (i = 0; buf[i]; i++) {
if (uio_resid(uio) < (user_ssize_t)buflen[i]) {
data->dead = true;
err = ENODEV;
break;
}
err = uiomove(buf[i], (int)buflen[i], uio);
if (err) {
break;
}
}
/*
* XXX: Stop gap! I really need to finish interruption plumbing.
*/
if (ticket->answered) {
err = EINTR;
}
/*
* The FORGET message is an example of a ticket that has explicitly
* been invalidated by the sender. The sender is not expecting or wanting
* a reply, so he sets the 'invalid' field in the ticket.
*/
fuse_ticket_drop_invalid(ticket);
return err;
}
int
fuse_device_write(dev_t dev, uio_t uio, __unused int ioflag)
{
int err = 0;
bool found = false;
struct fuse_device *fdev;
struct fuse_data *data;
struct fuse_ticket *ticket;
struct fuse_ticket *x_ticket;
struct fuse_out_header ohead;
fuse_trace_printf_func();
fdev = FUSE_DEVICE_FROM_UNIT_FAST(minor(dev));
if (!fdev) {
return ENXIO;
}
if (uio_resid(uio) < (user_ssize_t)sizeof(struct fuse_out_header)) {
log("fuse4x: Incorrect header size. Got %lld, expected at least %lu\n",
uio_resid(uio), sizeof(struct fuse_out_header));
return EINVAL;
}
if ((err = uiomove((caddr_t)&ohead, (int)sizeof(struct fuse_out_header), uio))) {
return err;
}
/* begin audit */
if (uio_resid(uio) + sizeof(struct fuse_out_header) != ohead.len) {
log("fuse4x: message body size does not match that in the header\n");
return EINVAL;
}
if (uio_resid(uio) && ohead.error) {
log("fuse4x: non-zero error for a message with a body\n");
return EINVAL;
}
ohead.error = -(ohead.error);
/* end audit */
data = fdev->data;
fuse_lck_mtx_lock(data->aw_mtx);
TAILQ_FOREACH_SAFE(ticket, &data->aw_head, aw_link, x_ticket) {
if (ticket->unique == ohead.unique) {
found = true;
TAILQ_REMOVE(&data->aw_head, ticket, aw_link);
break;
}
}
fuse_lck_mtx_unlock(data->aw_mtx);
if (found) {
if (ticket->aw_callback) {
memcpy(&ticket->aw_ohead, &ohead, sizeof(ohead));
err = ticket->aw_callback(ticket, uio);
} else {
fuse_ticket_drop(ticket);
return err;
}
} else {
/* ticket has no response callback */
}
return err;
}
int
fuse_devices_start(void)
{
int i = 0;
fuse_trace_printf_func();
bzero((void *)fuse_device_table, sizeof(fuse_device_table));
if ((fuse_cdev_major = cdevsw_add(-1, &fuse_device_cdevsw)) == -1) {
goto error;
}
for (i = 0; i < FUSE4X_NDEVICES; i++) {
dev_t dev = makedev(fuse_cdev_major, i);
fuse_device_table[i].cdev = devfs_make_node(
dev,
DEVFS_CHAR,
UID_ROOT,
GID_OPERATOR,
0666,
FUSE4X_DEVICE_BASENAME "%d",
i);
if (fuse_device_table[i].cdev == NULL) {
goto error;
}
fuse_device_table[i].data = NULL;
fuse_device_table[i].dev = dev;
fuse_device_table[i].pid = -1;
fuse_device_table[i].usecount = 0;
fuse_device_table[i].mtx = lck_mtx_alloc_init(fuse_lock_group,
fuse_lock_attr);
}
fuse_interface_available = true;
return KERN_SUCCESS;
error:
for (--i; i >= 0; i--) {
devfs_remove(fuse_device_table[i].cdev);
fuse_device_table[i].cdev = NULL;
fuse_device_table[i].dev = 0;
lck_mtx_free(fuse_device_table[i].mtx, fuse_lock_group);
}
(void)cdevsw_remove(fuse_cdev_major, &fuse_device_cdevsw);
fuse_cdev_major = -1;
return KERN_FAILURE;
}
int
fuse_devices_stop(void)
{
int i, ret;
fuse_trace_printf_func();
fuse_interface_available = false;
fuse_lck_mtx_lock(fuse_device_mutex);
if (fuse_cdev_major == -1) {
fuse_lck_mtx_unlock(fuse_device_mutex);
return KERN_SUCCESS;
}
for (i = 0; i < FUSE4X_NDEVICES; i++) {
char p_comm[MAXCOMLEN + 1] = { '?', '\0' };
if (fuse_device_table[i].usecount != 0) {
fuse_interface_available = true;
fuse_lck_mtx_unlock(fuse_device_mutex);
proc_name(fuse_device_table[i].pid, p_comm, MAXCOMLEN + 1);
log("fuse4x: /dev/fuse4x%d is still active (pid=%d %s)\n",
i, fuse_device_table[i].pid, p_comm);
return KERN_FAILURE;
}
if (fuse_device_table[i].data != NULL) {
fuse_interface_available = true;
fuse_lck_mtx_unlock(fuse_device_mutex);
proc_name(fuse_device_table[i].pid, p_comm, MAXCOMLEN + 1);
/* The pid can't possibly be active here. */
log("fuse4x: /dev/fuse4x%d has a lingering mount (pid=%d, %s)\n",
i, fuse_device_table[i].pid, p_comm);
return KERN_FAILURE;
}
}
/* No device is in use. */
for (i = 0; i < FUSE4X_NDEVICES; i++) {
devfs_remove(fuse_device_table[i].cdev);
lck_mtx_free(fuse_device_table[i].mtx, fuse_lock_group);
fuse_device_table[i].cdev = NULL;
fuse_device_table[i].dev = 0;
fuse_device_table[i].pid = -1;
fuse_device_table[i].mtx = NULL;
}
ret = cdevsw_remove(fuse_cdev_major, &fuse_device_cdevsw);
if (ret != fuse_cdev_major) {
log("fuse4x: fuse_cdev_major != return from cdevsw_remove()\n");
}
fuse_cdev_major = -1;
fuse_lck_mtx_unlock(fuse_device_mutex);
return KERN_SUCCESS;
}
int
fuse_device_kill(int unit, struct proc *p)
{
int error = ENOENT;
struct fuse_device *fdev;
fuse_trace_printf_func();
if ((unit < 0) || (unit >= FUSE4X_NDEVICES)) {
return EINVAL;
}
fdev = FUSE_DEVICE_FROM_UNIT_FAST(unit);
if (!fdev) {
return ENOENT;
}
fuse_lck_mtx_lock(fdev->mtx);
struct fuse_data *data = fdev->data;
if (data) {
error = EPERM;
if (p) {
kauth_cred_t request_cred = kauth_cred_proc_ref(p);
if ((kauth_cred_getuid(request_cred) == 0) ||
(fuse_match_cred(data->daemoncred, request_cred) == 0)) {
/* The following can block. */
fuse_data_kill(data);
fuse_reject_answers(data);
error = 0;
}
kauth_cred_unref(&request_cred);
}
}
fuse_lck_mtx_unlock(fdev->mtx);
return error;
}
int
fuse_device_print_vnodes(int unit_flags, struct proc *p)
{
int error = ENOENT;
struct fuse_device *fdev;
int unit = unit_flags;
if ((unit < 0) || (unit >= FUSE4X_NDEVICES)) {
return EINVAL;
}
fdev = FUSE_DEVICE_FROM_UNIT_FAST(unit);
if (!fdev) {
return ENOENT;
}
fuse_lck_mtx_lock(fdev->mtx);
struct fuse_data *data = fdev->data;
if (data) {
mount_t mp = data->mp;
if (vfs_busy(mp, LK_NOWAIT)) {
fuse_lck_mtx_unlock(fdev->mtx);
return EBUSY;
}
error = EPERM;
if (p) {
kauth_cred_t request_cred = kauth_cred_proc_ref(p);
if ((kauth_cred_getuid(request_cred) == 0) ||
(fuse_match_cred(data->daemoncred, request_cred) == 0)) {
fuse_internal_print_vnodes(mp);
error = 0;
}
kauth_cred_unref(&request_cred);
}
vfs_unbusy(mp);
}
fuse_lck_mtx_unlock(fdev->mtx);
return error;
}