1 /*
2 * This file and its contents are supplied under the terms of the
3 * Common Development and Distribution License ("CDDL"), version 1.0.
4 * You may only use this file in accordance with the terms of version
5 * 1.0 of the CDDL.
6 *
7 * A full copy of the text of the CDDL should have accompanied this
8 * source. A copy of the CDDL is also available via the Internet at
9 * http://www.illumos.org/license/CDDL.
10 */
11
12 /*
13 * Copyright (c) 2015 Joyent, Inc.
14 */
15
16 #include <sys/errno.h>
17 #include <sys/modctl.h>
18 #include <sys/types.h>
19 #include <sys/mkdev.h>
20 #include <sys/ddi.h>
21 #include <sys/sunddi.h>
22 #include <sys/vfs.h>
23 #include <sys/vfs_opreg.h>
24 #include <sys/systm.h>
25 #include <sys/id_space.h>
26 #include <sys/cmn_err.h>
27 #include <sys/ksynch.h>
28 #include <sys/policy.h>
29 #include <sys/mount.h>
30 #include <sys/sysmacros.h>
31
32 #include <sys/fs/bootfs_impl.h>
33
34 /*
35 * While booting, additional types of modules and files can be passed in to the
36 * loader. These include the familiar boot archive, as well as, a module hash
37 * and additional modules that are interpreted as files. As part of the handoff
38 * in early boot, information about these modules are saved as properties on the
39 * root of the devinfo tree, similar to other boot-time properties.
40 *
41 * This file system provides a read-only view of those additional files. Due to
42 * its limited scope, it has a slightly simpler construction than several other
43 * file systems. When mounted, it looks for the corresponding properties and
44 * creates bootfs_node_t's and vnodes for all of the corresponding files and
45 * directories that exist along the way. At this time, there are currently a
46 * rather small number of files passed in this way.
47 *
48 * This does lead to one behavior that folks used to other file systems might
49 * find peculiar. Because we are not always actively creating and destroying the
50 * required vnodes on demand, the count on the root vnode will not be going up
51 * accordingly with the existence of other vnodes. This means that a bootfs file
52 * system that is not in use will have all of its vnodes exist with a v_count of
53 * one.
54 */
55
56 major_t bootfs_major;
57 static int bootfs_fstype;
58 static id_space_t *bootfs_idspace;
59 static uint64_t bootfs_nactive;
60 static kmutex_t bootfs_lock;
61
62 static const char *bootfs_name = "bootfs";
63
64 static int
65 bootfs_mount(vfs_t *vfsp, vnode_t *mvp, struct mounta *uap, cred_t *cr)
66 {
67 int ret;
68 bootfs_t *bfs;
69 struct pathname dpn;
70 dev_t fsdev;
71
72 if ((ret = secpolicy_fs_mount(cr, mvp, vfsp)) != 0)
73 return (ret);
74
75 if (mvp->v_type != VDIR)
76 return (ENOTDIR);
77
78 if (uap->flags & MS_REMOUNT)
79 return (EBUSY);
80
81 mutex_enter(&mvp->v_lock);
82 if ((uap->flags & MS_OVERLAY) == 0 &&
83 (mvp->v_count != 1 || (mvp->v_flag & VROOT))) {
84 mutex_exit(&mvp->v_lock);
85 return (EBUSY);
86 }
87 mutex_exit(&mvp->v_lock);
88
89 /*
90 * We indicate that the backing store is bootfs. We don't want to use
91 * swap, because folks might think that this is putting all the data
92 * into memory ala tmpfs. Rather these modules are always in memory and
93 * there's nothing to be done about that.
94 */
95 vfs_setresource(vfsp, bootfs_name, 0);
96 bfs = kmem_zalloc(sizeof (bootfs_t), KM_NOSLEEP | KM_NORMALPRI);
97 if (bfs == NULL)
98 return (ENOMEM);
99
100 ret = pn_get(uap->dir,
101 (uap->flags & MS_SYSSPACE) ? UIO_SYSSPACE : UIO_USERSPACE, &dpn);
102 if (ret != 0) {
103 kmem_free(bfs, sizeof (bfs));
104 return (ret);
105 }
106
107 bfs->bfs_minor = id_alloc(bootfs_idspace);
108 bfs->bfs_kstat = kstat_create_zone("bootfs", bfs->bfs_minor, "bootfs",
109 "fs", KSTAT_TYPE_NAMED,
110 sizeof (bootfs_stat_t) / sizeof (kstat_named_t),
111 KSTAT_FLAG_VIRTUAL, GLOBAL_ZONEID);
112 if (bfs->bfs_kstat == NULL) {
113 id_free(bootfs_idspace, bfs->bfs_minor);
114 pn_free(&dpn);
115 kmem_free(bfs, sizeof (bfs));
116 return (ENOMEM);
117 }
118 bfs->bfs_kstat->ks_data = &bfs->bfs_stat;
119
120 fsdev = makedevice(bootfs_major, bfs->bfs_minor);
121 bfs->bfs_vfsp = vfsp;
122
123 vfsp->vfs_data = (caddr_t)bfs;
124 vfsp->vfs_fstype = bootfs_fstype;
125 vfsp->vfs_dev = fsdev;
126 vfsp->vfs_bsize = PAGESIZE;
127 vfsp->vfs_flag |= VFS_RDONLY | VFS_NOSETUID | VFS_NOTRUNC |
128 VFS_UNLINKABLE;
129 vfs_make_fsid(&vfsp->vfs_fsid, fsdev, bootfs_fstype);
130 bfs->bfs_mntpath = kmem_alloc(dpn.pn_pathlen + 1, KM_SLEEP);
131 bcopy(dpn.pn_path, bfs->bfs_mntpath, dpn.pn_pathlen);
132 bfs->bfs_mntpath[dpn.pn_pathlen] = '\0';
133 pn_free(&dpn);
134 list_create(&bfs->bfs_nodes, sizeof (bootfs_node_t),
135 offsetof(bootfs_node_t, bvn_alink));
136
137 kstat_named_init(&bfs->bfs_stat.bfss_nfiles, "nfiles",
138 KSTAT_DATA_UINT32);
139 kstat_named_init(&bfs->bfs_stat.bfss_ndirs, "ndirs",
140 KSTAT_DATA_UINT32);
141 kstat_named_init(&bfs->bfs_stat.bfss_nbytes, "nbytes",
142 KSTAT_DATA_UINT64);
143 kstat_named_init(&bfs->bfs_stat.bfss_ndups, "ndup",
144 KSTAT_DATA_UINT32);
145 kstat_named_init(&bfs->bfs_stat.bfss_ndiscards, "ndiscard",
146 KSTAT_DATA_UINT32);
147
148 bootfs_construct(bfs);
149
150 kstat_install(bfs->bfs_kstat);
151
152 return (0);
153 }
154
155 static int
156 bootfs_unmount(vfs_t *vfsp, int flag, cred_t *cr)
157 {
158 int ret;
159 bootfs_t *bfs = vfsp->vfs_data;
160 bootfs_node_t *bnp;
161
162 if ((ret = secpolicy_fs_unmount(cr, vfsp)) != 0)
163 return (ret);
164
165 if (flag & MS_FORCE)
166 return (ENOTSUP);
167
168 for (bnp = list_head(&bfs->bfs_nodes); bnp != NULL;
169 bnp = list_next(&bfs->bfs_nodes, bnp)) {
170 mutex_enter(&bnp->bvn_vnp->v_lock);
171 if (bnp->bvn_vnp->v_count > 1) {
172 mutex_exit(&bnp->bvn_vnp->v_lock);
173 return (EBUSY);
174 }
175 mutex_exit(&bnp->bvn_vnp->v_lock);
176 }
177
178 kstat_delete(bfs->bfs_kstat);
179 bootfs_destruct(bfs);
180 list_destroy(&bfs->bfs_nodes);
181 kmem_free(bfs->bfs_mntpath, strlen(bfs->bfs_mntpath) + 1);
182 id_free(bootfs_idspace, bfs->bfs_minor);
183 kmem_free(bfs, sizeof (bootfs_t));
184 return (0);
185 }
186
187 static int
188 bootfs_root(vfs_t *vfsp, vnode_t **vpp)
189 {
190 bootfs_t *bfs;
191
192 bfs = (bootfs_t *)vfsp->vfs_data;
193 *vpp = bfs->bfs_rootvn->bvn_vnp;
194 VN_HOLD(*vpp)
195
196 return (0);
197 }
198
199 static int
200 bootfs_statvfs(vfs_t *vfsp, struct statvfs64 *sbp)
201 {
202 const bootfs_t *bfs = (bootfs_t *)vfsp;
203 dev32_t d32;
204
205 sbp->f_bsize = PAGESIZE;
206 sbp->f_frsize = PAGESIZE;
207
208 sbp->f_blocks = bfs->bfs_stat.bfss_nbytes.value.ui64 >> PAGESHIFT;
209 sbp->f_bfree = 0;
210 sbp->f_bavail = 0;
211
212 sbp->f_files = bfs->bfs_stat.bfss_nfiles.value.ui32 +
213 bfs->bfs_stat.bfss_ndirs.value.ui32;
214 sbp->f_ffree = 0;
215 sbp->f_favail = 0;
216
217 (void) cmpldev(&d32, vfsp->vfs_dev);
218 sbp->f_fsid = d32;
219 (void) strlcpy(sbp->f_basetype, bootfs_name, FSTYPSZ);
220 bzero(sbp->f_fstr, sizeof (sbp->f_fstr));
221
222 return (0);
223 }
224
225 static const fs_operation_def_t bootfs_vfsops_tmpl[] = {
226 VFSNAME_MOUNT, { .vfs_mount = bootfs_mount },
227 VFSNAME_UNMOUNT, { .vfs_unmount = bootfs_unmount },
228 VFSNAME_ROOT, { .vfs_root = bootfs_root },
229 VFSNAME_STATVFS, { .vfs_statvfs = bootfs_statvfs },
230 NULL, NULL
231 };
232
233 static int
234 bootfs_init(int fstype, char *name)
235 {
236 int ret;
237
238 bootfs_fstype = fstype;
239 ASSERT(bootfs_fstype != 0);
240
241 ret = vfs_setfsops(fstype, bootfs_vfsops_tmpl, NULL);
242 if (ret != 0)
243 return (ret);
244
245 ret = vn_make_ops(name, bootfs_vnodeops_template, &bootfs_vnodeops);
246 if (ret != 0) {
247 (void) vfs_freevfsops_by_type(bootfs_fstype);
248 return (ret);
249 }
250
251 bootfs_major = getudev();
252 if (bootfs_major == (major_t)-1) {
253 cmn_err(CE_WARN, "bootfs_init: Can't get unique device number");
254 bootfs_major = 0;
255 }
256
257 bootfs_nactive = 0;
258 return (0);
259 }
260
261 static mntopts_t bootfs_mntopts = {
262 0, NULL
263 };
264
265 static vfsdef_t bootfs_vfsdef = {
266 VFSDEF_VERSION,
267 "bootfs",
268 bootfs_init,
269 VSW_HASPROTO|VSW_STATS,
270 &bootfs_mntopts
271 };
272
273 static struct modlfs bootfs_modlfs = {
274 &mod_fsops, "boot-time modules file system", &bootfs_vfsdef
275 };
276
277 static struct modlinkage bootfs_modlinkage = {
278 MODREV_1, &bootfs_modlfs, NULL
279 };
280
281 int
282 _init(void)
283 {
284 bootfs_node_cache = kmem_cache_create("bootfs_node_cache",
285 sizeof (bootfs_node_t), 0, bootfs_node_constructor,
286 bootfs_node_destructor, NULL, NULL, NULL, 0);
287 bootfs_idspace = id_space_create("bootfs_minors", 1, INT32_MAX);
288 mutex_init(&bootfs_lock, NULL, MUTEX_DEFAULT, NULL);
289
290 return (mod_install(&bootfs_modlinkage));
291 }
292
293 int
294 _info(struct modinfo *modinfop)
295 {
296 return (mod_info(&bootfs_modlinkage, modinfop));
297 }
298
299 int
300 _fini(void)
301 {
302 int err;
303
304 mutex_enter(&bootfs_lock);
305 if (bootfs_nactive > 0) {
306 mutex_exit(&bootfs_lock);
307 return (EBUSY);
308 }
309 mutex_exit(&bootfs_lock);
310
311 err = mod_remove(&bootfs_modlinkage);
312 if (err != 0)
313 return (err);
314
315 (void) vfs_freevfsops_by_type(bootfs_fstype);
316 vn_freevnodeops(bootfs_vnodeops);
317 id_space_destroy(bootfs_idspace);
318 mutex_destroy(&bootfs_lock);
319 kmem_cache_destroy(bootfs_node_cache);
320 return (err);
321 }