1 /* $NetBSD: fdesc_vfsops.c,v 1.91 2014/11/09 18:08:06 maxv Exp $ */
2
3 /*
4 * Copyright (c) 1992, 1993, 1995
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This code is derived from software donated to Berkeley by
8 * Jan-Simon Pendry.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 * @(#)fdesc_vfsops.c 8.10 (Berkeley) 5/14/95
35 *
36 * #Id: fdesc_vfsops.c,v 1.9 1993/04/06 15:28:33 jsp Exp #
37 */
38
39 /*
40 * /dev/fd Filesystem
41 */
42
43 #include <sys/cdefs.h>
44 __KERNEL_RCSID(0, "$NetBSD: fdesc_vfsops.c,v 1.91 2014/11/09 18:08:06 maxv Exp $");
45
46 #if defined(_KERNEL_OPT)
47 #include "opt_compat_netbsd.h"
48 #endif
49
50 #include <sys/param.h>
51 #include <sys/systm.h>
52 #include <sys/sysctl.h>
53 #include <sys/time.h>
54 #include <sys/proc.h>
55 #include <sys/resourcevar.h>
56 #include <sys/filedesc.h>
57 #include <sys/vnode.h>
58 #include <sys/mount.h>
59 #include <sys/dirent.h>
60 #include <sys/namei.h>
61 #include <sys/kauth.h>
62 #include <sys/module.h>
63
64 #include <miscfs/genfs/genfs.h>
65 #include <miscfs/fdesc/fdesc.h>
66
67 MODULE(MODULE_CLASS_VFS, fdesc, NULL);
68
69 VFS_PROTOS(fdesc);
70
71 static struct sysctllog *fdesc_sysctl_log;
72
73 /*
74 * Mount the per-process file descriptors (/dev/fd)
75 */
76 int
fdesc_mount(struct mount * mp,const char * path,void * data,size_t * data_len)77 fdesc_mount(struct mount *mp, const char *path, void *data, size_t *data_len)
78 {
79 struct lwp *l = curlwp;
80 int error = 0, ix;
81 struct vnode *rvp;
82
83 if (mp->mnt_flag & MNT_GETARGS) {
84 *data_len = 0;
85 return 0;
86 }
87 /*
88 * Update is a no-op
89 */
90 if (mp->mnt_flag & MNT_UPDATE)
91 return (EOPNOTSUPP);
92
93 ix = FD_ROOT;
94 error = vcache_get(mp, &ix, sizeof(ix), &rvp);
95 if (error)
96 return error;
97
98 mp->mnt_stat.f_namemax = FDESC_MAXNAMLEN;
99 mp->mnt_flag |= MNT_LOCAL;
100 mp->mnt_data = rvp;
101 vfs_getnewfsid(mp);
102
103 error = set_statvfs_info(path, UIO_USERSPACE, "fdesc", UIO_SYSSPACE,
104 mp->mnt_op->vfs_name, mp, l);
105 return error;
106 }
107
108 int
fdesc_start(struct mount * mp,int flags)109 fdesc_start(struct mount *mp, int flags)
110 {
111 return (0);
112 }
113
114 int
fdesc_unmount(struct mount * mp,int mntflags)115 fdesc_unmount(struct mount *mp, int mntflags)
116 {
117 int error;
118 int flags = 0;
119 struct vnode *rtvp = mp->mnt_data;
120
121 if (mntflags & MNT_FORCE)
122 flags |= FORCECLOSE;
123
124 if (rtvp->v_usecount > 1 && (mntflags & MNT_FORCE) == 0)
125 return (EBUSY);
126 if ((error = vflush(mp, rtvp, flags)) != 0)
127 return (error);
128
129 /*
130 * Blow it away for future re-use
131 */
132 vgone(rtvp);
133 mp->mnt_data = NULL;
134
135 return (0);
136 }
137
138 int
fdesc_root(struct mount * mp,struct vnode ** vpp)139 fdesc_root(struct mount *mp, struct vnode **vpp)
140 {
141 struct vnode *vp;
142
143 /*
144 * Return locked reference to root.
145 */
146 vp = mp->mnt_data;
147 vref(vp);
148 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
149 *vpp = vp;
150 return (0);
151 }
152
153 /*ARGSUSED*/
154 int
fdesc_sync(struct mount * mp,int waitfor,kauth_cred_t uc)155 fdesc_sync(struct mount *mp, int waitfor,
156 kauth_cred_t uc)
157 {
158
159 return (0);
160 }
161
162 /*
163 * Fdesc flat namespace lookup.
164 * Currently unsupported.
165 */
166 int
fdesc_vget(struct mount * mp,ino_t ino,struct vnode ** vpp)167 fdesc_vget(struct mount *mp, ino_t ino,
168 struct vnode **vpp)
169 {
170
171 return (EOPNOTSUPP);
172 }
173
174 int
fdesc_loadvnode(struct mount * mp,struct vnode * vp,const void * key,size_t key_len,const void ** new_key)175 fdesc_loadvnode(struct mount *mp, struct vnode *vp,
176 const void *key, size_t key_len, const void **new_key)
177 {
178 int ix;
179 struct fdescnode *fd;
180
181 KASSERT(key_len == sizeof(ix));
182 memcpy(&ix, key, key_len);
183
184 fd = kmem_alloc(sizeof(struct fdescnode), KM_SLEEP);
185 fd->fd_fd = -1;
186 fd->fd_link = NULL;
187 fd->fd_ix = ix;
188 fd->fd_vnode = vp;
189 vp->v_tag = VT_FDESC;
190 vp->v_op = fdesc_vnodeop_p;
191 vp->v_data = fd;
192 switch (ix) {
193 case FD_ROOT:
194 fd->fd_type = Froot;
195 vp->v_type = VDIR;
196 vp->v_vflag |= VV_ROOT;
197 break;
198 case FD_DEVFD:
199 fd->fd_type = Fdevfd;
200 vp->v_type = VDIR;
201 break;
202 case FD_CTTY:
203 fd->fd_type = Fctty;
204 vp->v_type = VCHR;
205 break;
206 case FD_STDIN:
207 fd->fd_type = Flink;
208 fd->fd_link = "fd/0";
209 vp->v_type = VLNK;
210 break;
211 case FD_STDOUT:
212 fd->fd_type = Flink;
213 fd->fd_link = "fd/1";
214 vp->v_type = VLNK;
215 break;
216 case FD_STDERR:
217 fd->fd_type = Flink;
218 fd->fd_link = "fd/2";
219 vp->v_type = VLNK;
220 break;
221 default:
222 KASSERT(ix >= FD_DESC);
223 fd->fd_type = Fdesc;
224 fd->fd_fd = ix - FD_DESC;
225 vp->v_type = VNON;
226 break;
227 }
228 uvm_vnp_setsize(vp, 0);
229 *new_key = &fd->fd_ix;
230
231 return 0;
232 }
233
234 extern const struct vnodeopv_desc fdesc_vnodeop_opv_desc;
235
236 const struct vnodeopv_desc * const fdesc_vnodeopv_descs[] = {
237 &fdesc_vnodeop_opv_desc,
238 NULL,
239 };
240
241 struct vfsops fdesc_vfsops = {
242 .vfs_name = MOUNT_FDESC,
243 .vfs_min_mount_data = 0,
244 .vfs_mount = fdesc_mount,
245 .vfs_start = fdesc_start,
246 .vfs_unmount = fdesc_unmount,
247 .vfs_root = fdesc_root,
248 .vfs_quotactl = (void *)eopnotsupp,
249 .vfs_statvfs = genfs_statvfs,
250 .vfs_sync = fdesc_sync,
251 .vfs_vget = fdesc_vget,
252 .vfs_loadvnode = fdesc_loadvnode,
253 .vfs_fhtovp = (void *)eopnotsupp,
254 .vfs_vptofh = (void *)eopnotsupp,
255 .vfs_init = fdesc_init,
256 .vfs_done = fdesc_done,
257 .vfs_snapshot = (void *)eopnotsupp,
258 .vfs_extattrctl = vfs_stdextattrctl,
259 .vfs_suspendctl = (void *)eopnotsupp,
260 .vfs_renamelock_enter = genfs_renamelock_enter,
261 .vfs_renamelock_exit = genfs_renamelock_exit,
262 .vfs_fsync = (void *)eopnotsupp,
263 .vfs_opv_descs = fdesc_vnodeopv_descs
264 };
265
266 static int
fdesc_modcmd(modcmd_t cmd,void * arg)267 fdesc_modcmd(modcmd_t cmd, void *arg)
268 {
269 int error;
270
271 switch (cmd) {
272 case MODULE_CMD_INIT:
273 error = vfs_attach(&fdesc_vfsops);
274 if (error != 0)
275 break;
276 sysctl_createv(&fdesc_sysctl_log, 0, NULL, NULL,
277 CTLFLAG_PERMANENT,
278 CTLTYPE_NODE, "fdesc",
279 SYSCTL_DESCR("File-descriptor file system"),
280 NULL, 0, NULL, 0,
281 CTL_VFS, 7, CTL_EOL);
282 /*
283 * XXX the "7" above could be dynamic, thereby eliminating one
284 * more instance of the "number to vfs" mapping problem, but
285 * "7" is the order as taken from sys/mount.h
286 */
287 break;
288 case MODULE_CMD_FINI:
289 error = vfs_detach(&fdesc_vfsops);
290 if (error != 0)
291 break;
292 sysctl_teardown(&fdesc_sysctl_log);
293 break;
294 default:
295 error = ENOTTY;
296 break;
297 }
298
299 return (error);
300 }
301