29ffb32ccd
Owning Giant in the init/uninit is accidental due to the moment where VFS modules initialization is performed, and is not enforced by the VFS interface. The Giant lock does not prevent a parallel execution of the code, it is VFS which implements the proper protocol. Approved by: des (pseudofs maintainer) Sponsored by: The FreeBSD Foundation MFC after: 1 week
315 lines
8.7 KiB
C
315 lines
8.7 KiB
C
/*-
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* Copyright (c) 2001 Dag-Erling Coïdan Smørgrav
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer
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* in this position and unchanged.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#ifndef _PSEUDOFS_H_INCLUDED
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#define _PSEUDOFS_H_INCLUDED
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#include <sys/jail.h>
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/*
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* Opaque structures
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*/
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struct mntarg;
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struct mount;
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struct nameidata;
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struct proc;
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struct sbuf;
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struct statfs;
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struct thread;
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struct uio;
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struct vfsconf;
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struct vnode;
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/*
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* Limits and constants
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*/
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#define PFS_NAMELEN 24
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#define PFS_FSNAMELEN 16 /* equal to MFSNAMELEN */
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#define PFS_DELEN (8 + PFS_NAMELEN)
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typedef enum {
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pfstype_none = 0,
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pfstype_root,
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pfstype_dir,
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pfstype_this,
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pfstype_parent,
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pfstype_file,
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pfstype_symlink,
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pfstype_procdir
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} pfs_type_t;
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/*
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* Flags
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*/
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#define PFS_RD 0x0001 /* readable */
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#define PFS_WR 0x0002 /* writeable */
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#define PFS_RDWR (PFS_RD|PFS_WR)
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#define PFS_RAWRD 0x0004 /* raw reader */
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#define PFS_RAWWR 0x0008 /* raw writer */
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#define PFS_RAW (PFS_RAWRD|PFS_RAWWR)
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#define PFS_PROCDEP 0x0010 /* process-dependent */
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/*
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* Data structures
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*/
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struct pfs_info;
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struct pfs_node;
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struct pfs_bitmap;
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/*
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* Init / uninit callback
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*/
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#define PFS_INIT_ARGS \
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struct pfs_info *pi, struct vfsconf *vfc
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#define PFS_INIT_ARGNAMES \
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pi, vfc
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#define PFS_INIT_PROTO(name) \
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int name(PFS_INIT_ARGS);
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typedef int (*pfs_init_t)(PFS_INIT_ARGS);
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/*
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* Filler callback
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* Called with proc held but unlocked
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*/
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#define PFS_FILL_ARGS \
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struct thread *td, struct proc *p, struct pfs_node *pn, \
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struct sbuf *sb, struct uio *uio
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#define PFS_FILL_ARGNAMES \
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td, p, pn, sb, uio
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#define PFS_FILL_PROTO(name) \
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int name(PFS_FILL_ARGS);
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typedef int (*pfs_fill_t)(PFS_FILL_ARGS);
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/*
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* Attribute callback
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* Called with proc locked
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*/
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struct vattr;
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#define PFS_ATTR_ARGS \
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struct thread *td, struct proc *p, struct pfs_node *pn, \
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struct vattr *vap
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#define PFS_ATTR_ARGNAMES \
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td, p, pn, vap
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#define PFS_ATTR_PROTO(name) \
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int name(PFS_ATTR_ARGS);
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typedef int (*pfs_attr_t)(PFS_ATTR_ARGS);
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struct pfs_bitmap; /* opaque */
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/*
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* Visibility callback
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* Called with proc locked
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*/
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#define PFS_VIS_ARGS \
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struct thread *td, struct proc *p, struct pfs_node *pn
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#define PFS_VIS_ARGNAMES \
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td, p, pn
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#define PFS_VIS_PROTO(name) \
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int name(PFS_VIS_ARGS);
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typedef int (*pfs_vis_t)(PFS_VIS_ARGS);
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/*
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* Ioctl callback
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* Called with proc locked
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*/
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#define PFS_IOCTL_ARGS \
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struct thread *td, struct proc *p, struct pfs_node *pn, \
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unsigned long cmd, void *data
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#define PFS_IOCTL_ARGNAMES \
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td, p, pn, cmd, data
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#define PFS_IOCTL_PROTO(name) \
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int name(PFS_IOCTL_ARGS);
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typedef int (*pfs_ioctl_t)(PFS_IOCTL_ARGS);
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/*
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* Getextattr callback
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* Called with proc locked
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*/
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#define PFS_GETEXTATTR_ARGS \
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struct thread *td, struct proc *p, struct pfs_node *pn, \
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int attrnamespace, const char *name, struct uio *uio, \
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size_t *size, struct ucred *cred
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#define PFS_GETEXTATTR_ARGNAMES \
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td, p, pn, attrnamespace, name, uio, size, cred
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#define PFS_GETEXTATTR_PROTO(name) \
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int name(PFS_GETEXTATTR_ARGS);
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struct ucred;
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typedef int (*pfs_getextattr_t)(PFS_GETEXTATTR_ARGS);
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/*
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* Last-close callback
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* Called with proc locked
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*/
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#define PFS_CLOSE_ARGS \
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struct thread *td, struct proc *p, struct pfs_node *pn
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#define PFS_CLOSE_ARGNAMES \
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td, p, pn
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#define PFS_CLOSE_PROTO(name) \
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int name(PFS_CLOSE_ARGS);
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typedef int (*pfs_close_t)(PFS_CLOSE_ARGS);
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/*
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* Destroy callback
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*/
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#define PFS_DESTROY_ARGS \
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struct pfs_node *pn
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#define PFS_DESTROY_ARGNAMES \
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pn
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#define PFS_DESTROY_PROTO(name) \
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int name(PFS_DESTROY_ARGS);
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typedef int (*pfs_destroy_t)(PFS_DESTROY_ARGS);
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/*
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* pfs_info: describes a pseudofs instance
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*
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* The pi_mutex is only used to avoid using the global subr_unit lock
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* for unrhdr. The rest of struct pfs_info is only modified during
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* vfs_init() and vfs_uninit() of the consumer filesystem.
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*/
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struct pfs_info {
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char pi_name[PFS_FSNAMELEN];
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pfs_init_t pi_init;
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pfs_init_t pi_uninit;
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/* members below this line are initialized at run time */
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struct pfs_node *pi_root;
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struct mtx pi_mutex;
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struct unrhdr *pi_unrhdr;
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};
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/*
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* pfs_node: describes a node (file or directory) within a pseudofs
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*
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* - Fields marked (o) are protected by the node's own mutex.
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* - Fields marked (p) are protected by the node's parent's mutex.
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* - Remaining fields are not protected by any lock and are assumed to be
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* immutable once the node has been created.
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*
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* To prevent deadlocks, if a node's mutex is to be held at the same time
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* as its parent's (e.g. when adding or removing nodes to a directory),
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* the parent's mutex must always be acquired first. Unfortunately, this
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* is not enforcable by WITNESS.
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*/
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struct pfs_node {
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char pn_name[PFS_NAMELEN];
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pfs_type_t pn_type;
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int pn_flags;
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struct mtx pn_mutex;
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void *pn_data; /* (o) */
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pfs_fill_t pn_fill;
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pfs_ioctl_t pn_ioctl;
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pfs_close_t pn_close;
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pfs_attr_t pn_attr;
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pfs_vis_t pn_vis;
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pfs_getextattr_t pn_getextattr;
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pfs_destroy_t pn_destroy;
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struct pfs_info *pn_info;
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u_int32_t pn_fileno; /* (o) */
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struct pfs_node *pn_parent; /* (o) */
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struct pfs_node *pn_nodes; /* (o) */
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struct pfs_node *pn_next; /* (p) */
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};
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/*
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* VFS interface
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*/
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int pfs_mount (struct pfs_info *pi, struct mount *mp);
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int pfs_cmount (struct mntarg *ma, void *data, uint64_t flags);
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int pfs_unmount (struct mount *mp, int mntflags);
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int pfs_root (struct mount *mp, int flags,
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struct vnode **vpp);
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int pfs_statfs (struct mount *mp, struct statfs *sbp);
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int pfs_init (struct pfs_info *pi, struct vfsconf *vfc);
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int pfs_uninit (struct pfs_info *pi, struct vfsconf *vfc);
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/*
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* Directory structure construction and manipulation
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*/
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struct pfs_node *pfs_create_dir (struct pfs_node *parent, const char *name,
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pfs_attr_t attr, pfs_vis_t vis,
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pfs_destroy_t destroy, int flags);
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struct pfs_node *pfs_create_file(struct pfs_node *parent, const char *name,
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pfs_fill_t fill, pfs_attr_t attr,
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pfs_vis_t vis, pfs_destroy_t destroy,
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int flags);
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struct pfs_node *pfs_create_link(struct pfs_node *parent, const char *name,
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pfs_fill_t fill, pfs_attr_t attr,
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pfs_vis_t vis, pfs_destroy_t destroy,
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int flags);
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struct pfs_node *pfs_find_node (struct pfs_node *parent, const char *name);
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void pfs_purge (struct pfs_node *pn);
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int pfs_destroy (struct pfs_node *pn);
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/*
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* Now for some initialization magic...
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*/
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#define PSEUDOFS(name, version, jflag) \
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\
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static struct pfs_info name##_info = { \
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#name, \
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name##_init, \
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name##_uninit, \
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}; \
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\
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static int \
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_##name##_mount(struct mount *mp) { \
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if (jflag && !prison_allow(curthread->td_ucred, jflag)) \
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return (EPERM); \
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return (pfs_mount(&name##_info, mp)); \
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} \
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\
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static int \
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_##name##_init(struct vfsconf *vfc) { \
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return (pfs_init(&name##_info, vfc)); \
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} \
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\
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static int \
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_##name##_uninit(struct vfsconf *vfc) { \
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return (pfs_uninit(&name##_info, vfc)); \
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} \
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\
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static struct vfsops name##_vfsops = { \
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.vfs_cmount = pfs_cmount, \
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.vfs_init = _##name##_init, \
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.vfs_mount = _##name##_mount, \
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.vfs_root = pfs_root, \
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.vfs_statfs = pfs_statfs, \
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.vfs_uninit = _##name##_uninit, \
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.vfs_unmount = pfs_unmount, \
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}; \
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VFS_SET(name##_vfsops, name, VFCF_SYNTHETIC | (jflag ? VFCF_JAIL : 0)); \
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MODULE_VERSION(name, version); \
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MODULE_DEPEND(name, pseudofs, 1, 1, 1);
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#endif
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