pseudofs.h

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    1 /*-
    2  * SPDX-License-Identifier: BSD-3-Clause
    3  *
    4  * Copyright (c) 2001 Dag-Erling Coïdan Smørgrav
    5  * All rights reserved.
    6  *
    7  * Redistribution and use in source and binary forms, with or without
    8  * modification, are permitted provided that the following conditions
    9  * are met:
   10  * 1. Redistributions of source code must retain the above copyright
   11  *    notice, this list of conditions and the following disclaimer
   12  *    in this position and unchanged.
   13  * 2. Redistributions in binary form must reproduce the above copyright
   14  *    notice, this list of conditions and the following disclaimer in the
   15  *    documentation and/or other materials provided with the distribution.
   16  * 3. The name of the author may not be used to endorse or promote products
   17  *    derived from this software without specific prior written permission.
   18  *
   19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   20  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   21  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   22  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
   23  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   24  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   28  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   29  *
   30  *      $FreeBSD$
   31  */
   32 
   33 #ifndef _PSEUDOFS_H_INCLUDED
   34 #define _PSEUDOFS_H_INCLUDED
   35 
   36 #include <sys/jail.h>
   37 
   38 /*
   39  * Opaque structures
   40  */
   41 struct mntarg;
   42 struct mount;
   43 struct nameidata;
   44 struct proc;
   45 struct sbuf;
   46 struct statfs;
   47 struct thread;
   48 struct uio;
   49 struct vfsconf;
   50 struct vnode;
   51 
   52 /*
   53  * Limits and constants
   54  */
   55 #define PFS_NAMELEN             128
   56 #define PFS_FSNAMELEN           16      /* equal to MFSNAMELEN */
   57 #define PFS_DELEN               (offsetof(struct dirent, d_name) + PFS_NAMELEN)
   58 
   59 typedef enum {
   60         pfstype_none = 0,
   61         pfstype_root,
   62         pfstype_dir,
   63         pfstype_this,
   64         pfstype_parent,
   65         pfstype_file,
   66         pfstype_symlink,
   67         pfstype_procdir
   68 } pfs_type_t;
   69 
   70 /*
   71  * Flags
   72  */
   73 #define PFS_RD          0x0001  /* readable */
   74 #define PFS_WR          0x0002  /* writeable */
   75 #define PFS_RDWR        (PFS_RD|PFS_WR)
   76 #define PFS_RAWRD       0x0004  /* raw reader */
   77 #define PFS_RAWWR       0x0008  /* raw writer */
   78 #define PFS_RAW         (PFS_RAWRD|PFS_RAWWR)
   79 #define PFS_PROCDEP     0x0010  /* process-dependent */
   80 #define PFS_NOWAIT      0x0020 /* allow malloc to fail */
   81 #define PFS_AUTODRAIN   0x0040  /* sbuf_print can sleep to drain */
   82 
   83 /*
   84  * Data structures
   85  */
   86 struct pfs_info;
   87 struct pfs_node;
   88 
   89 /*
   90  * Init / uninit callback
   91  */
   92 #define PFS_INIT_ARGS \
   93         struct pfs_info *pi, struct vfsconf *vfc
   94 #define PFS_INIT_ARGNAMES \
   95         pi, vfc
   96 #define PFS_INIT_PROTO(name) \
   97         int name(PFS_INIT_ARGS);
   98 typedef int (*pfs_init_t)(PFS_INIT_ARGS);
   99 
  100 /*
  101  * Filler callback
  102  * Called with proc held but unlocked
  103  */
  104 #define PFS_FILL_ARGS \
  105         struct thread *td, struct proc *p, struct pfs_node *pn, \
  106         struct sbuf *sb, struct uio *uio
  107 #define PFS_FILL_ARGNAMES \
  108         td, p, pn, sb, uio
  109 #define PFS_FILL_PROTO(name) \
  110         int name(PFS_FILL_ARGS);
  111 typedef int (*pfs_fill_t)(PFS_FILL_ARGS);
  112 
  113 /*
  114  * Attribute callback
  115  * Called with proc locked
  116  */
  117 struct vattr;
  118 #define PFS_ATTR_ARGS \
  119         struct thread *td, struct proc *p, struct pfs_node *pn, \
  120         struct vattr *vap
  121 #define PFS_ATTR_ARGNAMES \
  122         td, p, pn, vap
  123 #define PFS_ATTR_PROTO(name) \
  124         int name(PFS_ATTR_ARGS);
  125 typedef int (*pfs_attr_t)(PFS_ATTR_ARGS);
  126 
  127 /*
  128  * Visibility callback
  129  * Called with proc locked
  130  */
  131 #define PFS_VIS_ARGS \
  132         struct thread *td, struct proc *p, struct pfs_node *pn
  133 #define PFS_VIS_ARGNAMES \
  134         td, p, pn
  135 #define PFS_VIS_PROTO(name) \
  136         int name(PFS_VIS_ARGS);
  137 typedef int (*pfs_vis_t)(PFS_VIS_ARGS);
  138 
  139 /*
  140  * Ioctl callback
  141  * Called with proc locked
  142  */
  143 #define PFS_IOCTL_ARGS \
  144         struct thread *td, struct proc *p, struct pfs_node *pn, \
  145         unsigned long cmd, void *data
  146 #define PFS_IOCTL_ARGNAMES \
  147         td, p, pn, cmd, data
  148 #define PFS_IOCTL_PROTO(name) \
  149         int name(PFS_IOCTL_ARGS);
  150 typedef int (*pfs_ioctl_t)(PFS_IOCTL_ARGS);
  151 
  152 /*
  153  * Getextattr callback
  154  * Called with proc locked
  155  */
  156 #define PFS_GETEXTATTR_ARGS \
  157         struct thread *td, struct proc *p, struct pfs_node *pn, \
  158         int attrnamespace, const char *name, struct uio *uio,   \
  159         size_t *size, struct ucred *cred
  160 #define PFS_GETEXTATTR_ARGNAMES \
  161         td, p, pn, attrnamespace, name, uio, size, cred
  162 #define PFS_GETEXTATTR_PROTO(name) \
  163         int name(PFS_GETEXTATTR_ARGS);
  164 struct ucred;
  165 typedef int (*pfs_getextattr_t)(PFS_GETEXTATTR_ARGS);
  166 
  167 /*
  168  * Last-close callback
  169  * Called with proc locked
  170  */
  171 #define PFS_CLOSE_ARGS \
  172         struct thread *td, struct proc *p, struct pfs_node *pn
  173 #define PFS_CLOSE_ARGNAMES \
  174         td, p, pn
  175 #define PFS_CLOSE_PROTO(name) \
  176         int name(PFS_CLOSE_ARGS);
  177 typedef int (*pfs_close_t)(PFS_CLOSE_ARGS);
  178 
  179 /*
  180  * Destroy callback
  181  */
  182 #define PFS_DESTROY_ARGS \
  183         struct pfs_node *pn
  184 #define PFS_DESTROY_ARGNAMES \
  185         pn
  186 #define PFS_DESTROY_PROTO(name) \
  187         int name(PFS_DESTROY_ARGS);
  188 typedef int (*pfs_destroy_t)(PFS_DESTROY_ARGS);
  189 
  190 /*
  191  * pfs_info: describes a pseudofs instance
  192  *
  193  * The pi_mutex is only used to avoid using the global subr_unit lock
  194  * for unrhdr.  The rest of struct pfs_info is only modified during
  195  * vfs_init() and vfs_uninit() of the consumer filesystem.
  196  */
  197 struct pfs_info {
  198         char                     pi_name[PFS_FSNAMELEN];
  199         pfs_init_t               pi_init;
  200         pfs_init_t               pi_uninit;
  201 
  202         /* members below this line are initialized at run time */
  203         struct pfs_node         *pi_root;
  204         struct mtx               pi_mutex;
  205         struct unrhdr           *pi_unrhdr;
  206 };
  207 
  208 /*
  209  * pfs_node: describes a node (file or directory) within a pseudofs
  210  *
  211  * - Fields marked (o) are protected by the node's own mutex.
  212  * - Fields marked (p) are protected by the node's parent's mutex.
  213  * - Remaining fields are not protected by any lock and are assumed to be
  214  *   immutable once the node has been created.
  215  *
  216  * To prevent deadlocks, if a node's mutex is to be held at the same time
  217  * as its parent's (e.g. when adding or removing nodes to a directory),
  218  * the parent's mutex must always be acquired first.  Unfortunately, this
  219  * is not enforcable by WITNESS.
  220  */
  221 struct pfs_node {
  222         char                     pn_name[PFS_NAMELEN];
  223         pfs_type_t               pn_type;
  224         int                      pn_flags;
  225         struct mtx               pn_mutex;
  226         void                    *pn_data;               /* (o) */
  227 
  228         pfs_fill_t               pn_fill;
  229         pfs_ioctl_t              pn_ioctl;
  230         pfs_close_t              pn_close;
  231         pfs_attr_t               pn_attr;
  232         pfs_vis_t                pn_vis;
  233         pfs_getextattr_t         pn_getextattr;
  234         pfs_destroy_t            pn_destroy;
  235 
  236         struct pfs_info         *pn_info;
  237         u_int32_t                pn_fileno;             /* (o) */
  238 
  239         struct pfs_node         *pn_parent;             /* (o) */
  240         struct pfs_node         *pn_nodes;              /* (o) */
  241         struct pfs_node         *pn_last_node;          /* (o) */
  242         struct pfs_node         *pn_next;               /* (p) */
  243 };
  244 
  245 /*
  246  * VFS interface
  247  */
  248 int              pfs_mount      (struct pfs_info *pi, struct mount *mp);
  249 int              pfs_cmount     (struct mntarg *ma, void *data, uint64_t flags);
  250 int              pfs_unmount    (struct mount *mp, int mntflags);
  251 int              pfs_root       (struct mount *mp, int flags,
  252                                  struct vnode **vpp);
  253 int              pfs_statfs     (struct mount *mp, struct statfs *sbp);
  254 int              pfs_init       (struct pfs_info *pi, struct vfsconf *vfc);
  255 int              pfs_uninit     (struct pfs_info *pi, struct vfsconf *vfc);
  256 
  257 /*
  258  * Directory structure construction and manipulation
  259  */
  260 struct pfs_node *pfs_create_dir (struct pfs_node *parent, const char *name,
  261                                  pfs_attr_t attr, pfs_vis_t vis,
  262                                  pfs_destroy_t destroy, int flags);
  263 struct pfs_node *pfs_create_file(struct pfs_node *parent, const char *name,
  264                                  pfs_fill_t fill, pfs_attr_t attr,
  265                                  pfs_vis_t vis, pfs_destroy_t destroy,
  266                                  int flags);
  267 struct pfs_node *pfs_create_link(struct pfs_node *parent, const char *name,
  268                                  pfs_fill_t fill, pfs_attr_t attr,
  269                                  pfs_vis_t vis, pfs_destroy_t destroy,
  270                                  int flags);
  271 struct pfs_node *pfs_find_node  (struct pfs_node *parent, const char *name);
  272 void             pfs_purge      (struct pfs_node *pn);
  273 int              pfs_destroy    (struct pfs_node *pn);
  274 
  275 /*
  276  * Now for some initialization magic...
  277  */
  278 #define PSEUDOFS(name, version, flags)                                  \
  279                                                                         \
  280 static struct pfs_info name##_info = {                                  \
  281         #name,                                                          \
  282         name##_init,                                                    \
  283         name##_uninit,                                                  \
  284 };                                                                      \
  285                                                                         \
  286 static int                                                              \
  287 _##name##_mount(struct mount *mp) {                                     \
  288         return (pfs_mount(&name##_info, mp));                           \
  289 }                                                                       \
  290                                                                         \
  291 static int                                                              \
  292 _##name##_init(struct vfsconf *vfc) {                                   \
  293         return (pfs_init(&name##_info, vfc));                           \
  294 }                                                                       \
  295                                                                         \
  296 static int                                                              \
  297 _##name##_uninit(struct vfsconf *vfc) {                                 \
  298         return (pfs_uninit(&name##_info, vfc));                         \
  299 }                                                                       \
  300                                                                         \
  301 static struct vfsops name##_vfsops = {                                  \
  302         .vfs_cmount =           pfs_cmount,                             \
  303         .vfs_init =             _##name##_init,                         \
  304         .vfs_mount =            _##name##_mount,                        \
  305         .vfs_root =             pfs_root,                               \
  306         .vfs_statfs =           pfs_statfs,                             \
  307         .vfs_uninit =           _##name##_uninit,                       \
  308         .vfs_unmount =          pfs_unmount,                            \
  309 };                                                                      \
  310 VFS_SET(name##_vfsops, name, VFCF_SYNTHETIC | flags);                   \
  311 MODULE_VERSION(name, version);                                          \
  312 MODULE_DEPEND(name, pseudofs, 1, 1, 1);
  313 
  314 #endif
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FreeBSD/Linux Kernel Cross Reference sys/fs/pseudofs/pseudofs.h

FreeBSD/Linux Kernel Cross Reference
sys/fs/pseudofs/pseudofs.h
