FreeBSD/Linux Kernel Cross Reference
sys/fs/fuse/fuse_ipc.h

     /*-
      * 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.
     *
     * $FreeBSD$
     */
    
    #ifndef _FUSE_IPC_H_
    #define _FUSE_IPC_H_
    
    #include <sys/param.h>
    #include <sys/refcount.h>
    
    enum fuse_data_cache_mode {
            FUSE_CACHE_UC,
            FUSE_CACHE_WT,
            FUSE_CACHE_WB,
    };
    
    struct fuse_iov {
            void   *base;
            size_t  len;
            size_t  allocated_size;
            int     credit;
    };
    
    void fiov_init(struct fuse_iov *fiov, size_t size);
    void fiov_teardown(struct fuse_iov *fiov);
    void fiov_refresh(struct fuse_iov *fiov);
    void fiov_adjust(struct fuse_iov *fiov, size_t size);
    
    #define FUSE_DIMALLOC(fiov, spc1, spc2, amnt) do {              \
            fiov_adjust(fiov, (sizeof(*(spc1)) + (amnt)));          \
            (spc1) = (fiov)->base;                                  \
            (spc2) = (char *)(fiov)->base + (sizeof(*(spc1)));      \
    } while (0)
    
    #define FU_AT_LEAST(siz) max((siz), 160)
    
    #define FUSE_ASSERT_AW_DONE(ftick)                                      \
            KASSERT((ftick)->tk_aw_link.tqe_next == NULL &&                 \
                (ftick)->tk_aw_link.tqe_prev == NULL,                       \
               ("FUSE: ticket still on answer delivery list %p", (ftick)))
   
   #define FUSE_ASSERT_MS_DONE(ftick)                              \
           KASSERT((ftick)->tk_ms_link.stqe_next == NULL,          \
               ("FUSE: ticket still on message list %p", (ftick)))
   
   struct fuse_ticket;
   struct fuse_data;
   
   typedef int fuse_handler_t(struct fuse_ticket *ftick, struct uio *uio);
   
   struct fuse_ticket {
           /* fields giving the identity of the ticket */
           uint64_t                        tk_unique;
           struct fuse_data                *tk_data;
           int                             tk_flag;
           u_int                           tk_refcount;
           /* 
            * If this ticket's operation has been interrupted, this will hold the
            * unique value of the FUSE_INTERRUPT operation.  Otherwise, it will be
            * 0.
            */
           uint64_t                        irq_unique;
   
           /* fields for initiating an upgoing message */
           struct fuse_iov                 tk_ms_fiov;
           STAILQ_ENTRY(fuse_ticket)       tk_ms_link;
   
           /* fields for handling answers coming from userspace */
           struct fuse_iov                 tk_aw_fiov;
           struct fuse_out_header          tk_aw_ohead;
           int                             tk_aw_errno;
           struct mtx                      tk_aw_mtx;
           fuse_handler_t                  *tk_aw_handler;
           TAILQ_ENTRY(fuse_ticket)        tk_aw_link;
   };
   
   #define FT_ANSW  0x01  /* request of ticket has already been answered */
   #define FT_DIRTY 0x04  /* ticket has been used */
   
   static inline struct fuse_iov *
   fticket_resp(struct fuse_ticket *ftick)
   {
           return (&ftick->tk_aw_fiov);
   }
   
   static inline bool
   fticket_answered(struct fuse_ticket *ftick)
   {
           mtx_assert(&ftick->tk_aw_mtx, MA_OWNED);
           return (ftick->tk_flag & FT_ANSW);
   }
   
   static inline void
   fticket_set_answered(struct fuse_ticket *ftick)
   {
           mtx_assert(&ftick->tk_aw_mtx, MA_OWNED);
           ftick->tk_flag |= FT_ANSW;
   }
   
   static inline struct fuse_in_header*
   fticket_in_header(struct fuse_ticket *ftick)
   {
           return (struct fuse_in_header *)(ftick->tk_ms_fiov.base);
   }
   
   static inline enum fuse_opcode
   fticket_opcode(struct fuse_ticket *ftick)
   {
           return fticket_in_header(ftick)->opcode;
   }
   
   int fticket_pull(struct fuse_ticket *ftick, struct uio *uio);
   
   /*
    * The data representing a FUSE session.
    */
   struct fuse_data {
           struct cdev                     *fdev;
           struct mount                    *mp;
           struct vnode                    *vroot;
           struct ucred                    *daemoncred;
           int                             dataflags;
           int                             ref;
   
           struct mtx                      ms_mtx;
           STAILQ_HEAD(, fuse_ticket)      ms_head;
           int                             ms_count;
   
           struct mtx                      aw_mtx;
           TAILQ_HEAD(, fuse_ticket)       aw_head;
   
           /* 
            * Holds the next value of the FUSE operation unique value.
            * Also, serves as a wakeup channel to prevent any operations from
            * being created before INIT completes.
            */
           u_long                          ticketer;
   
           struct sx                       rename_lock;
   
           uint32_t                        fuse_libabi_major;
           uint32_t                        fuse_libabi_minor;
   
           uint32_t                        max_readahead_blocks;
           uint32_t                        max_write;
           uint32_t                        max_read;
   
           struct selinfo                  ks_rsel;
   
           int                             daemon_timeout;
           int                             linux_errnos;
           unsigned                        time_gran;
           /* A bitmask of FUSE RPCs that are not implemented by the server */
           uint64_t                        notimpl;
           /*
            * A bitmask of FUSE RPCs that are implemented by the server.
            * If an operation is not present in either notimpl or isimpl, then it
            * may be implemented by the server, but the kernel doesn't know for
            * sure.
            */
           uint64_t                        isimpl;
           uint64_t                        mnt_flag;
           enum fuse_data_cache_mode       cache_mode;
   };
   
   #define FSESS_DEAD                0x0001 /* session is to be closed */
   #define FSESS_INITED              0x0004 /* session has been inited */
   #define FSESS_DAEMON_CAN_SPY      0x0010 /* let non-owners access this fs */
                                            /* (and being observed by the daemon) */
   #define FSESS_PUSH_SYMLINKS_IN    0x0020 /* prefix absolute symlinks with mp */
   #define FSESS_DEFAULT_PERMISSIONS 0x0040 /* kernel does permission checking */
   #define FSESS_NO_OPEN_SUPPORT     0x0080 /* can elide FUSE_OPEN ops */
   #define FSESS_NO_OPENDIR_SUPPORT  0x0100 /* can elide FUSE_OPENDIR ops */
   #define FSESS_ASYNC_READ          0x1000 /* allow multiple reads of some file */
   #define FSESS_POSIX_LOCKS         0x2000 /* daemon supports POSIX locks */
   #define FSESS_EXPORT_SUPPORT      0x10000 /* daemon supports NFS-style lookups */
   #define FSESS_INTR                0x20000 /* interruptible mounts */
   #define FSESS_WARN_SHORT_WRITE    0x40000 /* Short write without direct_io */
   #define FSESS_WARN_WROTE_LONG     0x80000 /* Wrote more data than provided */
   #define FSESS_WARN_LSEXTATTR_LONG 0x100000 /* Returned too many extattrs */
   #define FSESS_WARN_CACHE_INCOHERENT 0x200000    /* Read cache incoherent */
   #define FSESS_WARN_WB_CACHE_INCOHERENT 0x400000 /* WB cache incoherent */
   #define FSESS_WARN_ILLEGAL_INODE  0x800000 /* Illegal inode for new file */
   #define FSESS_MNTOPTS_MASK      ( \
           FSESS_DAEMON_CAN_SPY | FSESS_PUSH_SYMLINKS_IN | \
           FSESS_DEFAULT_PERMISSIONS | FSESS_INTR)
   
   extern int fuse_data_cache_mode;
   
   static inline struct fuse_data *
   fuse_get_mpdata(struct mount *mp)
   {
           return mp->mnt_data;
   }
   
   static inline bool
   fsess_is_impl(struct mount *mp, int opcode)
   {
           struct fuse_data *data = fuse_get_mpdata(mp);
   
           return ((data->isimpl & (1ULL << opcode)) != 0);
   
   }
   
   static inline bool
   fsess_maybe_impl(struct mount *mp, int opcode)
   {
           struct fuse_data *data = fuse_get_mpdata(mp);
   
           return ((data->notimpl & (1ULL << opcode)) == 0);
   
   }
   
   static inline bool
   fsess_not_impl(struct mount *mp, int opcode)
   {
           struct fuse_data *data = fuse_get_mpdata(mp);
   
           return ((data->notimpl & (1ULL << opcode)) != 0);
   
   }
   
   static inline void
   fsess_set_impl(struct mount *mp, int opcode)
   {
           struct fuse_data *data = fuse_get_mpdata(mp);
   
           data->isimpl |= (1ULL << opcode);
   }
   
   static inline void
   fsess_set_notimpl(struct mount *mp, int opcode)
   {
           struct fuse_data *data = fuse_get_mpdata(mp);
   
           data->notimpl |= (1ULL << opcode);
   }
   
   static inline bool
   fsess_opt_datacache(struct mount *mp)
   {
           struct fuse_data *data = fuse_get_mpdata(mp);
   
           return (data->cache_mode != FUSE_CACHE_UC);
   }
   
   static inline bool
   fsess_opt_mmap(struct mount *mp)
   {
           return (fsess_opt_datacache(mp));
   }
   
   static inline bool
   fsess_opt_writeback(struct mount *mp)
   {
           struct fuse_data *data = fuse_get_mpdata(mp);
   
           return (data->cache_mode == FUSE_CACHE_WB);
   }
   
   /* Insert a new upgoing message */
   static inline void
   fuse_ms_push(struct fuse_ticket *ftick)
   {
           mtx_assert(&ftick->tk_data->ms_mtx, MA_OWNED);
           refcount_acquire(&ftick->tk_refcount);
           STAILQ_INSERT_TAIL(&ftick->tk_data->ms_head, ftick, tk_ms_link);
           ftick->tk_data->ms_count++;
   }
   
   /* Insert a new upgoing message to the front of the queue */
   static inline void
   fuse_ms_push_head(struct fuse_ticket *ftick)
   {
           mtx_assert(&ftick->tk_data->ms_mtx, MA_OWNED);
           refcount_acquire(&ftick->tk_refcount);
           STAILQ_INSERT_HEAD(&ftick->tk_data->ms_head, ftick, tk_ms_link);
           ftick->tk_data->ms_count++;
   }
   
   static inline struct fuse_ticket *
   fuse_ms_pop(struct fuse_data *data)
   {
           struct fuse_ticket *ftick = NULL;
   
           mtx_assert(&data->ms_mtx, MA_OWNED);
   
           if ((ftick = STAILQ_FIRST(&data->ms_head))) {
                   STAILQ_REMOVE_HEAD(&data->ms_head, tk_ms_link);
                   data->ms_count--;
   #ifdef INVARIANTS
                   MPASS(data->ms_count >= 0);
                   ftick->tk_ms_link.stqe_next = NULL;
   #endif
           }
   
           return (ftick);
   }
   
   static inline void
   fuse_aw_push(struct fuse_ticket *ftick)
   {
           mtx_assert(&ftick->tk_data->aw_mtx, MA_OWNED);
           refcount_acquire(&ftick->tk_refcount);
           TAILQ_INSERT_TAIL(&ftick->tk_data->aw_head, ftick, tk_aw_link);
   }
   
   static inline void
   fuse_aw_remove(struct fuse_ticket *ftick)
   {
           mtx_assert(&ftick->tk_data->aw_mtx, MA_OWNED);
           TAILQ_REMOVE(&ftick->tk_data->aw_head, ftick, tk_aw_link);
   #ifdef INVARIANTS
           ftick->tk_aw_link.tqe_next = NULL;
           ftick->tk_aw_link.tqe_prev = NULL;
   #endif
   }
   
   static inline struct fuse_ticket *
   fuse_aw_pop(struct fuse_data *data)
   {
           struct fuse_ticket *ftick;
   
           mtx_assert(&data->aw_mtx, MA_OWNED);
   
           if ((ftick = TAILQ_FIRST(&data->aw_head)) != NULL)
                   fuse_aw_remove(ftick);
   
           return (ftick);
   }
   
   struct fuse_ticket *fuse_ticket_fetch(struct fuse_data *data);
   int fuse_ticket_drop(struct fuse_ticket *ftick);
   void fuse_insert_callback(struct fuse_ticket *ftick, fuse_handler_t *handler);
   void fuse_insert_message(struct fuse_ticket *ftick, bool irq);
   
   static inline bool
   fuse_libabi_geq(struct fuse_data *data, uint32_t abi_maj, uint32_t abi_min)
   {
           return (data->fuse_libabi_major > abi_maj ||
               (data->fuse_libabi_major == abi_maj &&
                data->fuse_libabi_minor >= abi_min));
   }
   
   /* Print msg as a warning to the console, but no more than once per session */
   void fuse_warn(struct fuse_data *data, unsigned flag, const char *msg);
   
   struct fuse_data *fdata_alloc(struct cdev *dev, struct ucred *cred);
   void fdata_trydestroy(struct fuse_data *data);
   void fdata_set_dead(struct fuse_data *data);
   
   static inline bool
   fdata_get_dead(struct fuse_data *data)
   {
           return (data->dataflags & FSESS_DEAD);
   }
   
   struct fuse_dispatcher {
           struct fuse_ticket    *tick;
           struct fuse_in_header *finh;
   
           void    *indata;
           size_t   iosize;
           uint64_t nodeid;
           int      answ_stat;
           void    *answ;
   };
   
   static inline void
   fdisp_init(struct fuse_dispatcher *fdisp, size_t iosize)
   {
           fdisp->iosize = iosize;
           fdisp->tick = NULL;
   }
   
   static inline void
   fdisp_destroy(struct fuse_dispatcher *fdisp)
   {
           fuse_ticket_drop(fdisp->tick);
   #ifdef INVARIANTS
           fdisp->tick = NULL;
   #endif
   }
   
   void fdisp_make(struct fuse_dispatcher *fdip, enum fuse_opcode op,
       struct mount *mp, uint64_t nid, struct thread *td, struct ucred *cred);
   
   void fdisp_make_vp(struct fuse_dispatcher *fdip, enum fuse_opcode op,
       struct vnode *vp, struct thread *td, struct ucred *cred);
   
   void fdisp_refresh_vp(struct fuse_dispatcher *fdip, enum fuse_opcode op,
       struct vnode *vp, struct thread *td, struct ucred *cred);
   
   int fdisp_wait_answ(struct fuse_dispatcher *fdip);
   
   static inline int
   fdisp_simple_putget_vp(struct fuse_dispatcher *fdip, enum fuse_opcode op,
       struct vnode *vp, struct thread *td, struct ucred *cred)
   {
           fdisp_make_vp(fdip, op, vp, td, cred);
           return (fdisp_wait_answ(fdip));
   }
   
   #endif /* _FUSE_IPC_H_ */

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