1 /* $OpenBSD: fusebuf.c,v 1.18 2021/03/11 13:31:35 jsg Exp $ */ 2 /* 3 * Copyright (c) 2012-2013 Sylvestre Gallon <ccna.syl@gmail.com> 4 * 5 * Permission to use, copy, modify, and distribute this software for any 6 * purpose with or without fee is hereby granted, provided that the above 7 * copyright notice and this permission notice appear in all copies. 8 * 9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16 */ 17 18 #include <sys/param.h> 19 #include <sys/filedesc.h> 20 #include <sys/kernel.h> 21 #include <sys/malloc.h> 22 #include <sys/pool.h> 23 #include <sys/proc.h> 24 #include <sys/stat.h> 25 #include <sys/statvfs.h> 26 #include <sys/systm.h> 27 #include <sys/vnode.h> 28 #include <sys/fusebuf.h> 29 30 #include "fusefs_node.h" 31 #include "fusefs.h" 32 33 struct fusebuf * 34 fb_setup(size_t len, ino_t ino, int op, struct proc *p) 35 { 36 struct fusebuf *fbuf; 37 38 fbuf = pool_get(&fusefs_fbuf_pool, PR_WAITOK | PR_ZERO); 39 fbuf->fb_len = len; 40 fbuf->fb_err = 0; 41 arc4random_buf(&fbuf->fb_uuid, sizeof fbuf->fb_uuid); 42 fbuf->fb_type = op; 43 fbuf->fb_ino = ino; 44 /* 45 * When exposed to userspace, thread IDs have THREAD_PID_OFFSET added 46 * to keep them from overlapping the PID range. 47 */ 48 fbuf->fb_tid = p->p_tid + THREAD_PID_OFFSET; 49 fbuf->fb_uid = p->p_ucred->cr_uid; 50 fbuf->fb_gid = p->p_ucred->cr_gid; 51 fbuf->fb_umask = p->p_p->ps_fd->fd_cmask; 52 if (len == 0) 53 fbuf->fb_dat = NULL; 54 else 55 fbuf->fb_dat = (uint8_t *)malloc(len, M_FUSEFS, 56 M_WAITOK | M_ZERO); 57 58 return (fbuf); 59 } 60 61 /* 62 * Puts the fbuf on the queue and waits for the file system to process 63 * it. The current process will block indefinitely and cannot be 64 * interrupted or killed. This is consistent with how VFS system calls 65 * should behave. nfs supports the -ointr or -i mount option and FUSE 66 * can too but this is non-trivial. The file system daemon must be 67 * multi-threaded and also support being interrupted. Note that 68 * libfuse currently only supports single-threaded daemons. 69 * 70 * Why not timeout similar to mount_nfs -osoft? 71 * It introduces another point of failure and a possible mount option 72 * (to specify the timeout) that users need to understand and tune to 73 * avoid premature timeouts for slow file systems. More complexity, 74 * less reliability. 75 * 76 * In the case where the daemon has become unresponsive the daemon 77 * will have to be killed in order for the current process to 78 * wakeup. The FUSE device is automatically closed when the daemon 79 * terminates and any waiting fbuf is woken up. 80 */ 81 int 82 fb_queue(dev_t dev, struct fusebuf *fbuf) 83 { 84 fuse_device_queue_fbuf(dev, fbuf); 85 tsleep_nsec(fbuf, PWAIT, "fuse", INFSLP); 86 87 return (fbuf->fb_err); 88 } 89 90 void 91 fb_delete(struct fusebuf *fbuf) 92 { 93 if (fbuf != NULL) { 94 free(fbuf->fb_dat, M_FUSEFS, fbuf->fb_len); 95 pool_put(&fusefs_fbuf_pool, fbuf); 96 } 97 } 98