1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22 /*
23 * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
24 */
25
26 #include <sys/atomic.h>
27 #include <sys/cmn_err.h>
28 #include <sys/errno.h>
29 #include <sys/mount.h>
30 #include <sharefs/sharefs.h>
31 #include <sys/vfs_opreg.h>
32 #include <sys/policy.h>
33 #include <sys/sunddi.h>
34 #include <sys/sysmacros.h>
35 #include <sys/systm.h>
36
37 #include <sys/mntent.h>
38 #include <sys/vfs.h>
39
40 /*
41 * Kernel sharetab filesystem.
42 *
43 * This is a pseudo filesystem which exports information about shares currently
44 * in kernel memory. The only element of the pseudo filesystem is a file.
45 *
46 * This file contains functions that interact with the VFS layer.
47 *
48 * sharetab sharefs_datanode_t sharefs.c
49 *
50 */
51
52 vnodeops_t *sharefs_ops_data;
53
54 static const fs_operation_def_t sharefs_vfstops[];
55 static gfs_opsvec_t sharefs_opsvec[];
56
57 static int sharefs_init(int, char *);
58
59 /*
60 * The sharefs system call.
61 */
62 static struct sysent sharefs_sysent = {
63 3,
64 SE_32RVAL1 | SE_ARGC | SE_NOUNLOAD,
65 sharefs
66 };
67
68 static struct modlsys modlsys = {
69 &mod_syscallops,
70 "sharefs syscall",
71 &sharefs_sysent
72 };
73
74 #ifdef _SYSCALL32_IMPL
75 static struct modlsys modlsys32 = {
76 &mod_syscallops32,
77 "sharefs syscall (32-bit)",
78 &sharefs_sysent
79 };
80 #endif /* _SYSCALL32_IMPL */
81
82 /*
83 * Module linkage
84 */
85 static mntopts_t sharefs_mntopts = {
86 0,
87 NULL
88 };
89
90 static vfsdef_t vfw = {
91 VFSDEF_VERSION,
92 "sharefs",
93 sharefs_init,
94 VSW_HASPROTO | VSW_ZMOUNT,
95 &sharefs_mntopts,
96 };
97
98 extern struct mod_ops mod_fsops;
99
100 static struct modlfs modlfs = {
101 &mod_fsops,
102 "sharetab filesystem",
103 &vfw
104 };
105
106 static struct modlinkage modlinkage = {
107 MODREV_1,
108 &modlfs,
109 &modlsys,
110 #ifdef _SYSCALL32_IMPL
111 &modlsys32,
112 #endif
113 NULL
114 };
115
116 int
117 _init(void)
118 {
119 return (mod_install(&modlinkage));
120 }
121
122 int
123 _info(struct modinfo *modinfop)
124 {
125 return (mod_info(&modlinkage, modinfop));
126 }
127
128 int
129 _fini(void)
130 {
131 /*
132 * The sharetab filesystem cannot be unloaded.
133 */
134 return (EBUSY);
135 }
136
137 /*
138 * Filesystem initialization.
139 */
140
141 static int sharefs_fstype;
142 static major_t sharefs_major;
143 static minor_t sharefs_minor;
144
145 static gfs_opsvec_t sharefs_opsvec[] = {
146 { "sharefs sharetab file", sharefs_tops_data, &sharefs_ops_data },
147 { NULL }
148 };
149
150 /* ARGSUSED */
151 static int
152 sharefs_init(int fstype, char *name)
153 {
154 vfsops_t *vfsops;
155 int error;
156
157 sharefs_fstype = fstype;
158 if (error = vfs_setfsops(fstype, sharefs_vfstops, &vfsops)) {
159 cmn_err(CE_WARN, "sharefs_init: bad vfs ops template");
160 return (error);
161 }
162
163 if (error = gfs_make_opsvec(sharefs_opsvec)) {
164 (void) vfs_freevfsops(vfsops);
165 return (error);
166 }
167
168 if ((sharefs_major = getudev()) == (major_t)-1) {
169 cmn_err(CE_WARN,
170 "sharefs_init: can't get unique device number");
171 sharefs_major = 0;
172 }
173
174 sharefs_sharetab_init();
175
176 return (0);
177 }
178
179 /*
180 * VFS entry points
181 */
182 static int
183 sharefs_mount(vfs_t *vfsp, vnode_t *mvp, struct mounta *uap, cred_t *cr)
184 {
185 sharefs_vfs_t *data;
186 dev_t dev;
187
188 if (secpolicy_fs_mount(cr, mvp, vfsp) != 0)
189 return (EPERM);
190
191 if ((uap->flags & MS_OVERLAY) == 0 &&
192 (mvp->v_count > 1 || (mvp->v_flag & VROOT)))
193 return (EBUSY);
194
195 data = kmem_alloc(sizeof (sharefs_vfs_t), KM_SLEEP);
196
197 /*
198 * Initialize vfs fields
199 */
200 vfsp->vfs_bsize = DEV_BSIZE;
201 vfsp->vfs_fstype = sharefs_fstype;
202 do {
203 dev = makedevice(sharefs_major,
204 atomic_add_32_nv(&sharefs_minor, 1) & L_MAXMIN32);
205 } while (vfs_devismounted(dev));
206 vfs_make_fsid(&vfsp->vfs_fsid, dev, sharefs_fstype);
207 vfsp->vfs_data = data;
208 vfsp->vfs_dev = dev;
209
210 /*
211 * Create root
212 */
213 data->sharefs_vfs_root = sharefs_create_root_file(vfsp);
214
215 return (0);
216 }
217
218 static int
219 sharefs_unmount(vfs_t *vfsp, int flag, struct cred *cr)
220 {
221 sharefs_vfs_t *data;
222
223 if (secpolicy_fs_unmount(cr, vfsp) != 0)
224 return (EPERM);
225
226 /*
227 * We do not currently support forced unmounts
228 */
229 if (flag & MS_FORCE)
230 return (ENOTSUP);
231
232 /*
233 * We should never have a reference count of less than 2: one for the
234 * caller, one for the root vnode.
235 */
236 ASSERT(vfsp->vfs_count >= 2);
237
238 /*
239 * Any active vnodes will result in a hold on the root vnode
240 */
241 data = vfsp->vfs_data;
242 if (data->sharefs_vfs_root->v_count > 1)
243 return (EBUSY);
244
245 /*
246 * Only allow an unmount iff there are no entries in memory.
247 */
248 rw_enter(&sharetab_lock, RW_READER);
249 if (sharetab_size != 0) {
250 rw_exit(&sharetab_lock);
251 return (EBUSY);
252 }
253 rw_exit(&sharetab_lock);
254
255 /*
256 * Release the last hold on the root vnode
257 */
258 VN_RELE(data->sharefs_vfs_root);
259
260 kmem_free(data, sizeof (sharefs_vfs_t));
261
262 return (0);
263 }
264
265 static int
266 sharefs_root(vfs_t *vfsp, vnode_t **vpp)
267 {
268 sharefs_vfs_t *data = vfsp->vfs_data;
269
270 *vpp = data->sharefs_vfs_root;
271 VN_HOLD(*vpp);
272
273 return (0);
274 }
275
276 static int
277 sharefs_statvfs(vfs_t *vfsp, statvfs64_t *sp)
278 {
279 dev32_t d32;
280 int total = 1;
281
282 bzero(sp, sizeof (*sp));
283 sp->f_bsize = DEV_BSIZE;
284 sp->f_frsize = DEV_BSIZE;
285 sp->f_files = total;
286 sp->f_ffree = sp->f_favail = INT_MAX - total;
287 (void) cmpldev(&d32, vfsp->vfs_dev);
288 sp->f_fsid = d32;
289 (void) strlcpy(sp->f_basetype, vfssw[vfsp->vfs_fstype].vsw_name,
290 sizeof (sp->f_basetype));
291 sp->f_flag = vf_to_stf(vfsp->vfs_flag);
292 sp->f_namemax = SHAREFS_NAME_MAX;
293 (void) strlcpy(sp->f_fstr, "sharefs", sizeof (sp->f_fstr));
294
295 return (0);
296 }
297
298 static const fs_operation_def_t sharefs_vfstops[] = {
299 { VFSNAME_MOUNT, { .vfs_mount = sharefs_mount } },
300 { VFSNAME_UNMOUNT, { .vfs_unmount = sharefs_unmount } },
301 { VFSNAME_ROOT, { .vfs_root = sharefs_root } },
302 { VFSNAME_STATVFS, { .vfs_statvfs = sharefs_statvfs } },
303 { NULL }
304 };