FreeBSD/Linux Kernel Cross Reference
sys/fs/fuse/fuse_file.c

     /*-
      * SPDX-License-Identifier: BSD-3-Clause
      *
      * Copyright (c) 2007-2009 Google Inc. and Amit Singh
      * 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.
     *
     * Copyright (c) 2019 The FreeBSD Foundation
     *
     * Portions of this software were developed by BFF Storage Systems, LLC under
     * sponsorship from the FreeBSD Foundation.
     *
     * 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/param.h>
    #include <sys/systm.h>
    #include <sys/counter.h>
    #include <sys/module.h>
    #include <sys/errno.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/vnode.h>
    #include <sys/sdt.h>
    #include <sys/sysctl.h>
    
    #include "fuse.h"
    #include "fuse_file.h"
    #include "fuse_internal.h"
    #include "fuse_io.h"
    #include "fuse_ipc.h"
    #include "fuse_node.h"
    
    MALLOC_DEFINE(M_FUSE_FILEHANDLE, "fuse_filefilehandle", "FUSE file handle");
    
    SDT_PROVIDER_DECLARE(fusefs);
    /* 
     * Fuse trace probe:
     * arg0: verbosity.  Higher numbers give more verbose messages
     * arg1: Textual message
     */
   SDT_PROBE_DEFINE2(fusefs, , file, trace, "int", "char*");
   
   static counter_u64_t fuse_fh_count;
   
   SYSCTL_COUNTER_U64(_vfs_fusefs_stats, OID_AUTO, filehandle_count, CTLFLAG_RD,
       &fuse_fh_count, "number of open FUSE filehandles");
   
   /* Get the FUFH type for a particular access mode */
   static inline fufh_type_t
   fflags_2_fufh_type(int fflags)
   {
           if ((fflags & FREAD) && (fflags & FWRITE))
                   return FUFH_RDWR;
           else if (fflags & (FWRITE))
                   return FUFH_WRONLY;
           else if (fflags & (FREAD))
                   return FUFH_RDONLY;
           else if (fflags & (FEXEC))
                   return FUFH_EXEC;
           else
                   panic("FUSE: What kind of a flag is this (%x)?", fflags);
   }
   
   int
   fuse_filehandle_open(struct vnode *vp, int a_mode,
       struct fuse_filehandle **fufhp, struct thread *td, struct ucred *cred)
   {
           struct fuse_dispatcher fdi;
           struct fuse_open_in *foi;
           struct fuse_open_out *foo;
           fufh_type_t fufh_type;
   
           int err = 0;
           int oflags = 0;
           int op = FUSE_OPEN;
   
           fufh_type = fflags_2_fufh_type(a_mode);
           oflags = fufh_type_2_fflags(fufh_type);
   
           if (vnode_isdir(vp)) {
                   op = FUSE_OPENDIR;
                   /* vn_open_vnode already rejects FWRITE on directories */
                   MPASS(fufh_type == FUFH_RDONLY || fufh_type == FUFH_EXEC);
           }
           fdisp_init(&fdi, sizeof(*foi));
           fdisp_make_vp(&fdi, op, vp, td, cred);
   
           foi = fdi.indata;
           foi->flags = oflags;
   
           if ((err = fdisp_wait_answ(&fdi))) {
                   SDT_PROBE2(fusefs, , file, trace, 1,
                           "OUCH ... daemon didn't give fh");
                   if (err == ENOENT) {
                           fuse_internal_vnode_disappear(vp);
                   }
                   goto out;
           }
           foo = fdi.answ;
   
           fuse_filehandle_init(vp, fufh_type, fufhp, td, cred, foo);
           fuse_vnode_open(vp, foo->open_flags, td);
   
   out:
           fdisp_destroy(&fdi);
           return err;
   }
   
   int
   fuse_filehandle_close(struct vnode *vp, struct fuse_filehandle *fufh,
       struct thread *td, struct ucred *cred)
   {
           struct fuse_dispatcher fdi;
           struct fuse_release_in *fri;
   
           int err = 0;
           int op = FUSE_RELEASE;
   
           if (fuse_isdeadfs(vp)) {
                   goto out;
           }
           if (vnode_isdir(vp))
                   op = FUSE_RELEASEDIR;
           fdisp_init(&fdi, sizeof(*fri));
           fdisp_make_vp(&fdi, op, vp, td, cred);
           fri = fdi.indata;
           fri->fh = fufh->fh_id;
           fri->flags = fufh_type_2_fflags(fufh->fufh_type);
           /* 
            * If the file has a POSIX lock then we're supposed to set lock_owner.
            * If not, then lock_owner is undefined.  So we may as well always set
            * it.
            */
           fri->lock_owner = td->td_proc->p_pid;
   
           err = fdisp_wait_answ(&fdi);
           fdisp_destroy(&fdi);
   
   out:
           counter_u64_add(fuse_fh_count, -1);
           LIST_REMOVE(fufh, next);
           free(fufh, M_FUSE_FILEHANDLE);
   
           return err;
   }
   
   /*
    * Check for a valid file handle, first the type requested, but if that
    * isn't valid, try for FUFH_RDWR.
    * Return true if there is any file handle with the correct credentials and
    * a fufh type that includes the provided one.
    * A pid of 0 means "don't care"
    */
   bool
   fuse_filehandle_validrw(struct vnode *vp, int mode,
           struct ucred *cred, pid_t pid)
   {
           struct fuse_vnode_data *fvdat = VTOFUD(vp);
           struct fuse_filehandle *fufh;
           fufh_type_t fufh_type = fflags_2_fufh_type(mode);
   
           /* 
            * Unlike fuse_filehandle_get, we want to search for a filehandle with
            * the exact cred, and no fallback
            */
           LIST_FOREACH(fufh, &fvdat->handles, next) {
                   if (fufh->fufh_type == fufh_type &&
                       fufh->uid == cred->cr_uid &&
                       fufh->gid == cred->cr_rgid &&
                       (pid == 0 || fufh->pid == pid))
                           return true;
           }
   
           if (fufh_type == FUFH_EXEC)
                   return false;
   
           /* Fallback: find a RDWR list entry with the right cred */
           LIST_FOREACH(fufh, &fvdat->handles, next) {
                   if (fufh->fufh_type == FUFH_RDWR &&
                       fufh->uid == cred->cr_uid &&
                       fufh->gid == cred->cr_rgid &&
                       (pid == 0 || fufh->pid == pid))
                           return true;
           }
   
           return false;
   }
   
   int
   fuse_filehandle_get(struct vnode *vp, int fflag,
       struct fuse_filehandle **fufhp, struct ucred *cred, pid_t pid)
   {
           struct fuse_vnode_data *fvdat = VTOFUD(vp);
           struct fuse_filehandle *fufh;
           fufh_type_t fufh_type;
   
           fufh_type = fflags_2_fufh_type(fflag);
           /* cred can be NULL for in-kernel clients */
           if (cred == NULL)
                   goto fallback;
   
           LIST_FOREACH(fufh, &fvdat->handles, next) {
                   if (fufh->fufh_type == fufh_type &&
                       fufh->uid == cred->cr_uid &&
                       fufh->gid == cred->cr_rgid &&
                       (pid == 0 || fufh->pid == pid))
                           goto found;
           }
   
   fallback:
           /* Fallback: find a list entry with the right flags */
           LIST_FOREACH(fufh, &fvdat->handles, next) {
                   if (fufh->fufh_type == fufh_type)
                           break;
           }
   
           if (fufh == NULL)
                   return EBADF;
   
   found:
           if (fufhp != NULL)
                   *fufhp = fufh;
           return 0;
   }
   
   /* Get a file handle with any kind of flags */
   int
   fuse_filehandle_get_anyflags(struct vnode *vp,
       struct fuse_filehandle **fufhp, struct ucred *cred, pid_t pid)
   {
           struct fuse_vnode_data *fvdat = VTOFUD(vp);
           struct fuse_filehandle *fufh;
   
           if (cred == NULL)
                   goto fallback;
   
           LIST_FOREACH(fufh, &fvdat->handles, next) {
                   if (fufh->uid == cred->cr_uid &&
                       fufh->gid == cred->cr_rgid &&
                       (pid == 0 || fufh->pid == pid))
                           goto found;
           }
   
   fallback:
           /* Fallback: find any list entry */
           fufh = LIST_FIRST(&fvdat->handles);
   
           if (fufh == NULL)
                   return EBADF;
   
   found:
           if (fufhp != NULL)
                   *fufhp = fufh;
           return 0;
   }
   
   int
   fuse_filehandle_getrw(struct vnode *vp, int fflag,
       struct fuse_filehandle **fufhp, struct ucred *cred, pid_t pid)
   {
           int err;
   
           err = fuse_filehandle_get(vp, fflag, fufhp, cred, pid);
           if (err)
                   err = fuse_filehandle_get(vp, FREAD | FWRITE, fufhp, cred, pid);
           return err;
   }
   
   void
   fuse_filehandle_init(struct vnode *vp, fufh_type_t fufh_type,
       struct fuse_filehandle **fufhp, struct thread *td, struct ucred *cred,
       struct fuse_open_out *foo)
   {
           struct fuse_vnode_data *fvdat = VTOFUD(vp);
           struct fuse_filehandle *fufh;
   
           fufh = malloc(sizeof(struct fuse_filehandle), M_FUSE_FILEHANDLE,
                   M_WAITOK);
           MPASS(fufh != NULL);
           fufh->fh_id = foo->fh;
           fufh->fufh_type = fufh_type;
           fufh->gid = cred->cr_rgid;
           fufh->uid = cred->cr_uid;
           fufh->pid = td->td_proc->p_pid;
           fufh->fuse_open_flags = foo->open_flags;
           if (!FUFH_IS_VALID(fufh)) {
                   panic("FUSE: init: invalid filehandle id (type=%d)", fufh_type);
           }
           LIST_INSERT_HEAD(&fvdat->handles, fufh, next);
           if (fufhp != NULL)
                   *fufhp = fufh;
   
           counter_u64_add(fuse_fh_count, 1);
   
           if (foo->open_flags & FOPEN_DIRECT_IO) {
                   ASSERT_VOP_ELOCKED(vp, __func__);
                   VTOFUD(vp)->flag |= FN_DIRECTIO;
                   fuse_io_invalbuf(vp, td);
           } else {
                   if ((foo->open_flags & FOPEN_KEEP_CACHE) == 0)
                           fuse_io_invalbuf(vp, td);
                   VTOFUD(vp)->flag &= ~FN_DIRECTIO;
           }
   
   }
   
   void
   fuse_file_init(void)
   {
           fuse_fh_count = counter_u64_alloc(M_WAITOK);
   }
   
   void
   fuse_file_destroy(void)
   {
           counter_u64_free(fuse_fh_count);
   }

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