xref: /illumos-gate/usr/src/uts/common/fs/proc/prvfsops.c (revision 34bbc83afbf22a6f8e504cb99d76c97c017cb5f4)
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  * Copyright (c) 1989, 2010, Oracle and/or its affiliates. All rights reserved.
23  */
24 
25 /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
26 /*	  All Rights Reserved	*/
27 
28 
29 #include <sys/types.h>
30 #include <sys/param.h>
31 #include <sys/cmn_err.h>
32 #include <sys/cred.h>
33 #include <sys/debug.h>
34 #include <sys/errno.h>
35 #include <sys/proc.h>
36 #include <sys/procfs.h>
37 #include <sys/stat.h>
38 #include <sys/statvfs.h>
39 #include <sys/sysmacros.h>
40 #include <sys/systm.h>
41 #include <sys/zone.h>
42 #include <sys/var.h>
43 #include <sys/vfs.h>
44 #include <sys/vfs_opreg.h>
45 #include <sys/vnode.h>
46 #include <sys/mode.h>
47 #include <sys/signal.h>
48 #include <sys/user.h>
49 #include <sys/mount.h>
50 #include <sys/bitmap.h>
51 #include <sys/kmem.h>
52 #include <sys/policy.h>
53 #include <fs/fs_subr.h>
54 #include <fs/proc/prdata.h>
55 
56 /*
57  * This is the loadable module wrapper.
58  */
59 #include <sys/modctl.h>
60 
61 static int prinit();
62 
63 static mntopts_t proc_mntopts = {
64 	.mo_count = 0,
65 	.mo_list = NULL
66 };
67 
68 static vfsdef_t vfw = {
69 	VFSDEF_VERSION,
70 	"proc",
71 	prinit,
72 	VSW_HASPROTO|VSW_STATS|VSW_XID|VSW_ZMOUNT,
73 	&proc_mntopts
74 };
75 
76 /*
77  * Module linkage information for the kernel.
78  */
79 extern struct mod_ops mod_fsops;
80 
81 static struct modlfs modlfs = {
82 	&mod_fsops, "filesystem for proc", &vfw
83 };
84 
85 static struct modlinkage modlinkage = {
86 	MODREV_1, (void *)&modlfs, NULL
87 };
88 
89 int
90 _init(void)
91 {
92 	return (mod_install(&modlinkage));
93 }
94 
95 int
96 _info(struct modinfo *modinfop)
97 {
98 	return (mod_info(&modlinkage, modinfop));
99 }
100 
101 /*
102  * N.B.
103  * No _fini routine. The module cannot be unloaded once loaded.
104  * The NO_UNLOAD_STUB in modstubs.S must change if this module
105  * is ever modified to become unloadable.
106  */
107 
108 int		nproc_highbit;		/* highbit(v.v_nproc) */
109 
110 static int	procfstype;
111 static major_t	procfs_major;
112 static minor_t	procfs_minor;
113 static kmutex_t	procfs_minor_lock;
114 
115 static kmutex_t	pr_mount_lock;
116 
117 /*
118  * /proc VFS operations vector.
119  */
120 static int	prmount(), prunmount(), prroot(), prstatvfs();
121 
122 static void
123 prinitrootnode(prnode_t *pnp, vfs_t *vfsp)
124 {
125 	struct vnode *vp;
126 
127 	bzero((caddr_t)pnp, sizeof (*pnp));
128 	pnp->pr_vnode = vp = vn_alloc(KM_SLEEP);
129 
130 	mutex_init(&pnp->pr_mutex, NULL, MUTEX_DEFAULT, NULL);
131 	vp->v_flag = VROOT|VNOCACHE|VNOMAP|VNOSWAP|VNOMOUNT;
132 	VN_SET_VFS_TYPE_DEV(vp, vfsp, VDIR, 0);
133 	vn_setops(vp, prvnodeops);
134 	vp->v_data = (caddr_t)pnp;
135 	pnp->pr_type = PR_PROCDIR;
136 	pnp->pr_mode = 0555;	/* read-search by everyone */
137 	vn_exists(vp);
138 }
139 
140 static int
141 prinit(int fstype, char *name)
142 {
143 	static const fs_operation_def_t pr_vfsops_template[] = {
144 		VFSNAME_MOUNT,		{ .vfs_mount = prmount },
145 		VFSNAME_UNMOUNT,	{ .vfs_unmount = prunmount },
146 		VFSNAME_ROOT,		{ .vfs_root = prroot },
147 		VFSNAME_STATVFS,	{ .vfs_statvfs = prstatvfs },
148 		NULL,			NULL
149 	};
150 	extern const fs_operation_def_t pr_vnodeops_template[];
151 	int error;
152 
153 	nproc_highbit = highbit(v.v_proc);
154 	procfstype = fstype;
155 	ASSERT(procfstype != 0);
156 	/*
157 	 * Associate VFS ops vector with this fstype.
158 	 */
159 	error = vfs_setfsops(fstype, pr_vfsops_template, NULL);
160 	if (error != 0) {
161 		cmn_err(CE_WARN, "prinit: bad vfs ops template");
162 		return (error);
163 	}
164 
165 	/*
166 	 * Set up vnode ops vector too.
167 	 */
168 
169 	error = vn_make_ops(name, pr_vnodeops_template, &prvnodeops);
170 	if (error != 0) {
171 		(void) vfs_freevfsops_by_type(fstype);
172 		cmn_err(CE_WARN, "prinit: bad vnode ops template");
173 		return (error);
174 	}
175 
176 	/*
177 	 * Assign a unique "device" number (used by stat(2)).
178 	 */
179 	if ((procfs_major = getudev()) == (major_t)-1) {
180 		cmn_err(CE_WARN, "prinit: can't get unique device number");
181 		procfs_major = 0;
182 	}
183 	mutex_init(&pr_mount_lock, NULL, MUTEX_DEFAULT, NULL);
184 	mutex_init(&procfs_minor_lock, NULL, MUTEX_DEFAULT, NULL);
185 
186 	return (0);
187 }
188 
189 /* ARGSUSED */
190 static int
191 prmount(struct vfs *vfsp, struct vnode *mvp,
192     struct mounta *uap, struct cred *cr)
193 {
194 	prnode_t *pnp;
195 	zone_t *zone = curproc->p_zone;
196 
197 	if (secpolicy_fs_mount(cr, mvp, vfsp) != 0)
198 		return (EPERM);
199 
200 	if (mvp->v_type != VDIR)
201 		return (ENOTDIR);
202 
203 	if (zone == global_zone) {
204 		zone_t *mntzone;
205 
206 		mntzone = zone_find_by_path(refstr_value(vfsp->vfs_mntpt));
207 		zone_rele(mntzone);
208 		if (zone != mntzone)
209 			return (EBUSY);
210 	}
211 	/*
212 	 * Having the resource be anything but "proc" doesn't make sense
213 	 */
214 	vfs_setresource(vfsp, "proc", 0);
215 
216 	pnp = kmem_alloc(sizeof (*pnp), KM_SLEEP);
217 	mutex_enter(&pr_mount_lock);
218 
219 	mutex_enter(&mvp->v_lock);
220 	if ((uap->flags & MS_OVERLAY) == 0 &&
221 	    (mvp->v_count > 1 || (mvp->v_flag & VROOT))) {
222 		mutex_exit(&mvp->v_lock);
223 		mutex_exit(&pr_mount_lock);
224 		kmem_free(pnp, sizeof (*pnp));
225 		return (EBUSY);
226 	}
227 	mutex_exit(&mvp->v_lock);
228 
229 	prinitrootnode(pnp, vfsp);
230 	vfsp->vfs_fstype = procfstype;
231 	vfsp->vfs_data = (caddr_t)pnp;
232 	vfsp->vfs_bsize = DEV_BSIZE;
233 	/*
234 	 * find an available minor device number for this mount
235 	 */
236 	mutex_enter(&procfs_minor_lock);
237 	do {
238 		vfsp->vfs_dev = makedevice(procfs_major, procfs_minor);
239 		procfs_minor = (procfs_minor + 1) & L_MAXMIN32;
240 	} while (vfs_devismounted(vfsp->vfs_dev));
241 	mutex_exit(&procfs_minor_lock);
242 	vfs_make_fsid(&vfsp->vfs_fsid, vfsp->vfs_dev, procfstype);
243 
244 	mutex_exit(&pr_mount_lock);
245 	return (0);
246 }
247 
248 /* ARGSUSED */
249 static int
250 prunmount(struct vfs *vfsp, int flag, struct cred *cr)
251 {
252 	prnode_t *pnp = (prnode_t *)vfsp->vfs_data;
253 	vnode_t *vp = PTOV(pnp);
254 
255 	mutex_enter(&pr_mount_lock);
256 	if (secpolicy_fs_unmount(cr, vfsp) != 0) {
257 		mutex_exit(&pr_mount_lock);
258 		return (EPERM);
259 	}
260 
261 	/*
262 	 * forced unmount is not supported by this file system
263 	 * and thus, ENOTSUP, is being returned.
264 	 */
265 	if (flag & MS_FORCE) {
266 		mutex_exit(&pr_mount_lock);
267 		return (ENOTSUP);
268 	}
269 
270 	/*
271 	 * Ensure that no /proc vnodes are in use on this mount point.
272 	 */
273 	mutex_enter(&vp->v_lock);
274 	if (vp->v_count > 1) {
275 		mutex_exit(&vp->v_lock);
276 		mutex_exit(&pr_mount_lock);
277 		return (EBUSY);
278 	}
279 
280 	mutex_exit(&vp->v_lock);
281 	mutex_exit(&pr_mount_lock);
282 	vn_invalid(vp);
283 	vn_free(vp);
284 	kmem_free(pnp, sizeof (*pnp));
285 	return (0);
286 }
287 
288 /* ARGSUSED */
289 static int
290 prroot(struct vfs *vfsp, struct vnode **vpp)
291 {
292 	vnode_t *vp = PTOV((prnode_t *)vfsp->vfs_data);
293 
294 	VN_HOLD(vp);
295 	*vpp = vp;
296 	return (0);
297 }
298 
299 static int
300 prstatvfs(struct vfs *vfsp, struct statvfs64 *sp)
301 {
302 	int n;
303 	dev32_t d32;
304 	extern uint_t nproc;
305 
306 	n = v.v_proc - nproc;
307 
308 	bzero((caddr_t)sp, sizeof (*sp));
309 	sp->f_bsize	= DEV_BSIZE;
310 	sp->f_frsize	= DEV_BSIZE;
311 	sp->f_blocks	= (fsblkcnt64_t)0;
312 	sp->f_bfree	= (fsblkcnt64_t)0;
313 	sp->f_bavail	= (fsblkcnt64_t)0;
314 	sp->f_files	= (fsfilcnt64_t)v.v_proc + 2;
315 	sp->f_ffree	= (fsfilcnt64_t)n;
316 	sp->f_favail	= (fsfilcnt64_t)n;
317 	(void) cmpldev(&d32, vfsp->vfs_dev);
318 	sp->f_fsid	= d32;
319 	(void) strcpy(sp->f_basetype, vfssw[procfstype].vsw_name);
320 	sp->f_flag = vf_to_stf(vfsp->vfs_flag);
321 	sp->f_namemax = 64;		/* quite arbitrary */
322 	bzero(sp->f_fstr, sizeof (sp->f_fstr));
323 	(void) strcpy(sp->f_fstr, "/proc");
324 	(void) strcpy(&sp->f_fstr[6], "/proc");
325 	return (0);
326 }
327