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/* $OpenBSD: fusebuf.c,v 1.17 2019/12/05 10:41:08 mpi Exp $ */
/*
* Copyright (c) 2012-2013 Sylvestre Gallon <ccna.syl@gmail.com>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/param.h>
#include <sys/filedesc.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/pool.h>
#include <sys/proc.h>
#include <sys/stat.h>
#include <sys/statvfs.h>
#include <sys/systm.h>
#include <sys/vnode.h>
#include <sys/fusebuf.h>
#include "fusefs_node.h"
#include "fusefs.h"
struct fusebuf *
fb_setup(size_t len, ino_t ino, int op, struct proc *p)
{
struct fusebuf *fbuf;
fbuf = pool_get(&fusefs_fbuf_pool, PR_WAITOK | PR_ZERO);
fbuf->fb_len = len;
fbuf->fb_err = 0;
arc4random_buf(&fbuf->fb_uuid, sizeof fbuf->fb_uuid);
fbuf->fb_type = op;
fbuf->fb_ino = ino;
/*
* When exposed to userspace, thread IDs have THREAD_PID_OFFSET added
* to keep them from overlapping the PID range.
*/
fbuf->fb_tid = p->p_tid + THREAD_PID_OFFSET;
fbuf->fb_uid = p->p_ucred->cr_uid;
fbuf->fb_gid = p->p_ucred->cr_gid;
fbuf->fb_umask = p->p_p->ps_fd->fd_cmask;
if (len == 0)
fbuf->fb_dat = NULL;
else
fbuf->fb_dat = (uint8_t *)malloc(len, M_FUSEFS,
M_WAITOK | M_ZERO);
return (fbuf);
}
/*
* Puts the fbuf on the queue and waits for the file system to process
* it. The current process will block indefinitely and cannot be
* interrupted or killed. This is consistent with how VFS system calls
* should behave. nfs supports the -ointr or -i mount option and FUSE
* can too but this is non-trivial. The file system daemon must be
* multi-threaded and also support being interrupted. Note that
* libfuse currently only supports single-threaded deamons.
*
* Why not timeout similar to mount_nfs -osoft?
* It introduces another point of failure and a possible mount option
* (to specify the timeout) that users need to understand and tune to
* avoid premature timeouts for slow file systems. More complexity,
* less reliability.
*
* In the case where the daemon has become unresponsive the daemon
* will have to be killed in order for the current process to
* wakeup. The FUSE device is automatically closed when the daemon
* terminates and any waiting fbuf is woken up.
*/
int
fb_queue(dev_t dev, struct fusebuf *fbuf)
{
fuse_device_queue_fbuf(dev, fbuf);
tsleep_nsec(fbuf, PWAIT, "fuse", INFSLP);
return (fbuf->fb_err);
}
void
fb_delete(struct fusebuf *fbuf)
{
if (fbuf != NULL) {
free(fbuf->fb_dat, M_FUSEFS, fbuf->fb_len);
pool_put(&fusefs_fbuf_pool, fbuf);
}
}
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