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freebsd-dev/sys/fs/pseudofs/pseudofs.h
Kelly Yancey c9ad8a67af Restore the ability to mount procfs and fdescfs filesystems via the 
mount(2) system call:

  * Add cmount hook to fdescfs and pseudofs (and, by extension, procfs and
    linprocfs).  This (mostly) restores the ability to mount these
    filesystems using the old mount(2) system call (see below for the
    rest of the fix).

  * Remove not-NULL check for the data argument from the mount(2) entry
    point.  Per the mount(2) man page, it is up to the individual
    filesystem being mounted to verify data.  Or, in the case of procfs,
    etc. the filesystem is free to ignore the data parameter if it does
    not use it.  Enforcing data to be not-NULL in the mount(2) system call
    entry point prevented passing NULL to filesystems which ignored the
    data pointer value.  Apparently, passing NULL was common practice
    in such cases, as even our own mount_std(8) used to do it in the
    pre-nmount(2) world.

All userland programs in the tree were converted to nmount(2) long ago,
but I've found at least one external program which broke due to this
(presumably unintentional) mount(2) API change.  One could argue that
external programs should also be converted to nmount(2), but then there
isn't much point in keeping the mount(2) interface for backward
compatibility if it isn't backward compatible.
2006-05-15 19:42:10 +00:00

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/*-
* Copyright (c) 2001 Dag-Erling Coïdan Smørgrav
* All rights reserved.
*
* 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
* in this position and unchanged.
* 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.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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 _PSEUDOFS_H_INCLUDED
#define _PSEUDOFS_H_INCLUDED
/*
* Opaque structures
*/
struct mntarg;
struct mount;
struct nameidata;
struct proc;
struct sbuf;
struct statfs;
struct thread;
struct uio;
struct vfsconf;
struct vnode;
/*
* Limits and constants
*/
#define PFS_NAMELEN 24
#define PFS_FSNAMELEN 16 /* equal to MFSNAMELEN */
#define PFS_DELEN (8 + PFS_NAMELEN)
typedef enum {
pfstype_none = 0,
pfstype_root,
pfstype_dir,
pfstype_this,
pfstype_parent,
pfstype_file,
pfstype_symlink,
pfstype_procdir
} pfs_type_t;
/*
* Flags
*/
#define PFS_RD 0x0001 /* readable */
#define PFS_WR 0x0002 /* writeable */
#define PFS_RDWR (PFS_RD|PFS_WR)
#define PFS_RAWRD 0x0004 /* raw reader */
#define PFS_RAWWR 0x0008 /* raw writer */
#define PFS_RAW (PFS_RAWRD|PFS_RAWWR)
#define PFS_PROCDEP 0x0010 /* process-dependent */
#define PFS_DISABLED 0x8000 /* node is disabled */
/*
* Data structures
*/
struct pfs_info;
struct pfs_node;
struct pfs_bitmap;
/*
* Init / uninit callback
*/
#define PFS_INIT_ARGS \
struct pfs_info *pi, struct vfsconf *vfc
#define PFS_INIT_PROTO(name) \
int name(PFS_INIT_ARGS);
typedef int (*pfs_init_t)(PFS_INIT_ARGS);
/*
* Filler callback
*/
#define PFS_FILL_ARGS \
struct thread *td, struct proc *p, struct pfs_node *pn, \
struct sbuf *sb, struct uio *uio
#define PFS_FILL_PROTO(name) \
int name(PFS_FILL_ARGS);
typedef int (*pfs_fill_t)(PFS_FILL_ARGS);
/*
* Attribute callback
*/
struct vattr;
#define PFS_ATTR_ARGS \
struct thread *td, struct proc *p, struct pfs_node *pn, \
struct vattr *vap
#define PFS_ATTR_PROTO(name) \
int name(PFS_ATTR_ARGS);
typedef int (*pfs_attr_t)(PFS_ATTR_ARGS);
struct pfs_bitmap; /* opaque */
/*
* Visibility callback
*/
#define PFS_VIS_ARGS \
struct thread *td, struct proc *p, struct pfs_node *pn
#define PFS_VIS_PROTO(name) \
int name(PFS_VIS_ARGS);
typedef int (*pfs_vis_t)(PFS_VIS_ARGS);
/*
* Ioctl callback
*/
#define PFS_IOCTL_ARGS \
struct thread *td, struct proc *p, struct pfs_node *pn, \
unsigned long cmd, void *data
#define PFS_IOCTL_PROTO(name) \
int name(PFS_IOCTL_ARGS);
typedef int (*pfs_ioctl_t)(PFS_IOCTL_ARGS);
/*
* Getextattr callback
*/
#define PFS_GETEXTATTR_ARGS \
struct thread *td, struct proc *p, struct pfs_node *pn, \
int attrnamespace, const char *name, struct uio *uio, \
size_t *size, struct ucred *cred
#define PFS_GETEXTATTR_PROTO(name) \
int name(PFS_GETEXTATTR_ARGS);
struct ucred;
typedef int (*pfs_getextattr_t)(PFS_GETEXTATTR_ARGS);
/*
* Last-close callback
*/
#define PFS_CLOSE_ARGS \
struct thread *td, struct proc *p, struct pfs_node *pn
#define PFS_CLOSE_PROTO(name) \
int name(PFS_CLOSE_ARGS);
typedef int (*pfs_close_t)(PFS_CLOSE_ARGS);
/*
* pfs_info: describes a pseudofs instance
*/
struct pfs_info {
char pi_name[PFS_FSNAMELEN];
pfs_init_t pi_init;
pfs_init_t pi_uninit;
/* members below this line aren't initialized */
struct pfs_node *pi_root;
/* currently, the mutex is only used to protect the bitmap */
struct mtx pi_mutex;
struct unrhdr *pi_unrhdr;
};
/*
* pfs_node: describes a node (file or directory) within a pseudofs
*/
struct pfs_node {
char pn_name[PFS_NAMELEN];
pfs_type_t pn_type;
union {
void *_pn_dummy;
pfs_fill_t _pn_func;
struct pfs_node *_pn_nodes;
} u1;
#define pn_func u1._pn_func
#define pn_nodes u1._pn_nodes
pfs_ioctl_t pn_ioctl;
pfs_close_t pn_close;
pfs_attr_t pn_attr;
pfs_vis_t pn_vis;
pfs_getextattr_t pn_getextattr;
void *pn_data;
int pn_flags;
struct pfs_info *pn_info;
struct pfs_node *pn_parent;
struct pfs_node *pn_next;
u_int32_t pn_fileno;
};
/*
* VFS interface
*/
int pfs_mount (struct pfs_info *pi, struct mount *mp,
struct thread *td);
int pfs_cmount (struct mntarg *ma, void *data, int flags,
struct thread *td);
int pfs_unmount (struct mount *mp, int mntflags,
struct thread *td);
int pfs_root (struct mount *mp, int flags,
struct vnode **vpp, struct thread *td);
int pfs_statfs (struct mount *mp, struct statfs *sbp,
struct thread *td);
int pfs_init (struct pfs_info *pi, struct vfsconf *vfc);
int pfs_uninit (struct pfs_info *pi, struct vfsconf *vfc);
/*
* Directory structure construction and manipulation
*/
struct pfs_node *pfs_create_dir (struct pfs_node *parent, const char *name,
pfs_attr_t attr, pfs_vis_t vis, int flags);
struct pfs_node *pfs_create_file(struct pfs_node *parent, const char *name,
pfs_fill_t fill, pfs_attr_t attr,
pfs_vis_t vis, int flags);
struct pfs_node *pfs_create_link(struct pfs_node *parent, const char *name,
pfs_fill_t fill, pfs_attr_t attr,
pfs_vis_t vis, int flags);
struct pfs_node *pfs_find_node (struct pfs_node *parent, const char *name);
int pfs_disable (struct pfs_node *pn);
int pfs_enable (struct pfs_node *pn);
int pfs_destroy (struct pfs_node *pn);
/*
* Now for some initialization magic...
*/
#define PSEUDOFS(name, version) \
\
static struct pfs_info name##_info = { \
#name, \
name##_init, \
name##_uninit, \
}; \
\
static int \
_##name##_mount(struct mount *mp, struct thread *td) { \
return pfs_mount(&name##_info, mp, td); \
} \
\
static int \
_##name##_init(struct vfsconf *vfc) { \
return pfs_init(&name##_info, vfc); \
} \
\
static int \
_##name##_uninit(struct vfsconf *vfc) { \
return pfs_uninit(&name##_info, vfc); \
} \
\
static struct vfsops name##_vfsops = { \
.vfs_cmount = pfs_cmount, \
.vfs_init = _##name##_init, \
.vfs_mount = _##name##_mount, \
.vfs_root = pfs_root, \
.vfs_statfs = pfs_statfs, \
.vfs_uninit = _##name##_uninit, \
.vfs_unmount = pfs_unmount, \
}; \
VFS_SET(name##_vfsops, name, VFCF_SYNTHETIC); \
MODULE_VERSION(name, version); \
MODULE_DEPEND(name, pseudofs, 1, 1, 1);
#endif
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