1 /* $NetBSD: fdesc_vfsops.c,v 1.96 2020/04/13 19:23:18 ad 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 1.96 2020/04/13 19:23:18 ad 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 /*
72 * Mount the per-process file descriptors (/dev/fd)
73 */
74 int
fdesc_mount(struct mount * mp,const char * path,void * data,size_t * data_len)75 fdesc_mount(struct mount *mp, const char *path, void *data, size_t *data_len)
76 {
77 struct lwp *l = curlwp;
78 int error = 0, ix;
79 struct vnode *rvp;
80
81 if (mp->mnt_flag & MNT_GETARGS) {
82 *data_len = 0;
83 return 0;
84 }
85 /*
86 * Update is a no-op
87 */
88 if (mp->mnt_flag & MNT_UPDATE)
89 return (EOPNOTSUPP);
90
91 ix = FD_ROOT;
92 error = vcache_get(mp, &ix, sizeof(ix), &rvp);
93 if (error)
94 return error;
95
96 mp->mnt_stat.f_namemax = FDESC_MAXNAMLEN;
97 mp->mnt_flag |= MNT_LOCAL;
98 mp->mnt_data = rvp;
99 vfs_getnewfsid(mp);
100
101 error = set_statvfs_info(path, UIO_USERSPACE, "fdesc", UIO_SYSSPACE,
102 mp->mnt_op->vfs_name, mp, l);
103 return error;
104 }
105
106 int
fdesc_start(struct mount * mp,int flags)107 fdesc_start(struct mount *mp, int flags)
108 {
109 return (0);
110 }
111
112 int
fdesc_unmount(struct mount * mp,int mntflags)113 fdesc_unmount(struct mount *mp, int mntflags)
114 {
115 int error;
116 int flags = 0;
117 struct vnode *rtvp = mp->mnt_data;
118
119 if (mntflags & MNT_FORCE)
120 flags |= FORCECLOSE;
121
122 if (vrefcnt(rtvp) > 1 && (mntflags & MNT_FORCE) == 0)
123 return (EBUSY);
124 if ((error = vflush(mp, rtvp, flags)) != 0)
125 return (error);
126
127 /*
128 * Blow it away for future re-use
129 */
130 vgone(rtvp);
131 mp->mnt_data = NULL;
132
133 return (0);
134 }
135
136 int
fdesc_root(struct mount * mp,int lktype,struct vnode ** vpp)137 fdesc_root(struct mount *mp, int lktype, struct vnode **vpp)
138 {
139 struct vnode *vp;
140
141 /*
142 * Return locked reference to root.
143 */
144 vp = mp->mnt_data;
145 vref(vp);
146 vn_lock(vp, lktype | LK_RETRY);
147 *vpp = vp;
148 return (0);
149 }
150
151 /*ARGSUSED*/
152 int
fdesc_sync(struct mount * mp,int waitfor,kauth_cred_t uc)153 fdesc_sync(struct mount *mp, int waitfor,
154 kauth_cred_t uc)
155 {
156
157 return (0);
158 }
159
160 /*
161 * Fdesc flat namespace lookup.
162 * Currently unsupported.
163 */
164 int
fdesc_vget(struct mount * mp,ino_t ino,int lktype,struct vnode ** vpp)165 fdesc_vget(struct mount *mp, ino_t ino, int lktype,
166 struct vnode **vpp)
167 {
168
169 return (EOPNOTSUPP);
170 }
171
172 int
fdesc_loadvnode(struct mount * mp,struct vnode * vp,const void * key,size_t key_len,const void ** new_key)173 fdesc_loadvnode(struct mount *mp, struct vnode *vp,
174 const void *key, size_t key_len, const void **new_key)
175 {
176 int ix;
177 struct fdescnode *fd;
178
179 KASSERT(key_len == sizeof(ix));
180 memcpy(&ix, key, key_len);
181
182 fd = kmem_alloc(sizeof(struct fdescnode), KM_SLEEP);
183 fd->fd_fd = -1;
184 fd->fd_link = NULL;
185 fd->fd_ix = ix;
186 fd->fd_vnode = vp;
187 vp->v_tag = VT_FDESC;
188 vp->v_op = fdesc_vnodeop_p;
189 vp->v_data = fd;
190 switch (ix) {
191 case FD_ROOT:
192 fd->fd_type = Froot;
193 vp->v_type = VDIR;
194 vp->v_vflag |= VV_ROOT;
195 break;
196 case FD_DEVFD:
197 fd->fd_type = Fdevfd;
198 vp->v_type = VDIR;
199 break;
200 case FD_CTTY:
201 fd->fd_type = Fctty;
202 vp->v_type = VCHR;
203 break;
204 case FD_STDIN:
205 fd->fd_type = Flink;
206 fd->fd_link = "fd/0";
207 vp->v_type = VLNK;
208 break;
209 case FD_STDOUT:
210 fd->fd_type = Flink;
211 fd->fd_link = "fd/1";
212 vp->v_type = VLNK;
213 break;
214 case FD_STDERR:
215 fd->fd_type = Flink;
216 fd->fd_link = "fd/2";
217 vp->v_type = VLNK;
218 break;
219 default:
220 KASSERT(ix >= FD_DESC);
221 fd->fd_type = Fdesc;
222 fd->fd_fd = ix - FD_DESC;
223 vp->v_type = VNON;
224 break;
225 }
226 uvm_vnp_setsize(vp, 0);
227 *new_key = &fd->fd_ix;
228
229 return 0;
230 }
231
232 extern const struct vnodeopv_desc fdesc_vnodeop_opv_desc;
233
234 const struct vnodeopv_desc * const fdesc_vnodeopv_descs[] = {
235 &fdesc_vnodeop_opv_desc,
236 NULL,
237 };
238
239 struct vfsops fdesc_vfsops = {
240 .vfs_name = MOUNT_FDESC,
241 .vfs_min_mount_data = 0,
242 .vfs_mount = fdesc_mount,
243 .vfs_start = fdesc_start,
244 .vfs_unmount = fdesc_unmount,
245 .vfs_root = fdesc_root,
246 .vfs_quotactl = (void *)eopnotsupp,
247 .vfs_statvfs = genfs_statvfs,
248 .vfs_sync = fdesc_sync,
249 .vfs_vget = fdesc_vget,
250 .vfs_loadvnode = fdesc_loadvnode,
251 .vfs_fhtovp = (void *)eopnotsupp,
252 .vfs_vptofh = (void *)eopnotsupp,
253 .vfs_init = fdesc_init,
254 .vfs_done = fdesc_done,
255 .vfs_snapshot = (void *)eopnotsupp,
256 .vfs_extattrctl = vfs_stdextattrctl,
257 .vfs_suspendctl = genfs_suspendctl,
258 .vfs_renamelock_enter = genfs_renamelock_enter,
259 .vfs_renamelock_exit = genfs_renamelock_exit,
260 .vfs_fsync = (void *)eopnotsupp,
261 .vfs_opv_descs = fdesc_vnodeopv_descs
262 };
263
264 SYSCTL_SETUP(fdesc_sysctl_setup, "fdesc sysctl")
265 {
266
267 sysctl_createv(clog, 0, NULL, NULL,
268 CTLFLAG_PERMANENT,
269 CTLTYPE_NODE, "fdesc",
270 SYSCTL_DESCR("File-descriptor file system"),
271 NULL, 0, NULL, 0,
272 CTL_VFS, 7, CTL_EOL);
273 /*
274 * XXX the "7" above could be dynamic, thereby eliminating one
275 * more instance of the "number to vfs" mapping problem, but
276 * "7" is the order as taken from sys/mount.h
277 */
278 }
279
280 static int
fdesc_modcmd(modcmd_t cmd,void * arg)281 fdesc_modcmd(modcmd_t cmd, void *arg)
282 {
283 int error;
284
285 switch (cmd) {
286 case MODULE_CMD_INIT:
287 error = vfs_attach(&fdesc_vfsops);
288 if (error != 0)
289 break;
290 break;
291 case MODULE_CMD_FINI:
292 error = vfs_detach(&fdesc_vfsops);
293 if (error != 0)
294 break;
295 break;
296 default:
297 error = ENOTTY;
298 break;
299 }
300
301 return (error);
302 }
303