xref: /titanic_41/usr/src/uts/common/fs/proc/prvfsops.c (revision 45916cd2fec6e79bca5dee0421bd39e3c2910d1e)
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 2006 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
27 /*	  All Rights Reserved  	*/
28 
29 
30 #pragma ident	"%Z%%M%	%I%	%E% SMI"	/* SVr4.0 1.25  */
31 
32 #include <sys/types.h>
33 #include <sys/param.h>
34 #include <sys/cmn_err.h>
35 #include <sys/cred.h>
36 #include <sys/debug.h>
37 #include <sys/errno.h>
38 #include <sys/proc.h>
39 #include <sys/procfs.h>
40 #include <sys/stat.h>
41 #include <sys/statvfs.h>
42 #include <sys/sysmacros.h>
43 #include <sys/systm.h>
44 #include <sys/zone.h>
45 #include <sys/var.h>
46 #include <sys/vfs.h>
47 #include <sys/vnode.h>
48 #include <sys/mode.h>
49 #include <sys/signal.h>
50 #include <sys/user.h>
51 #include <sys/mount.h>
52 #include <sys/bitmap.h>
53 #include <sys/kmem.h>
54 #include <sys/policy.h>
55 #include <fs/fs_subr.h>
56 #include <fs/proc/prdata.h>
57 
58 /*
59  * This is the loadable module wrapper.
60  */
61 #include <sys/modctl.h>
62 
63 static int prinit();
64 
65 static mntopts_t proc_mntopts = {
66 	NULL,
67 	0
68 };
69 
70 static vfsdef_t vfw = {
71 	VFSDEF_VERSION,
72 	"proc",
73 	prinit,
74 	VSW_HASPROTO|VSW_STATS,
75 	&proc_mntopts
76 };
77 
78 /*
79  * Module linkage information for the kernel.
80  */
81 extern struct mod_ops mod_fsops;
82 
83 static struct modlfs modlfs = {
84 	&mod_fsops, "filesystem for proc", &vfw
85 };
86 
87 static struct modlinkage modlinkage = {
88 	MODREV_1, (void *)&modlfs, NULL
89 };
90 
91 int
92 _init(void)
93 {
94 	return (mod_install(&modlinkage));
95 }
96 
97 int
98 _info(struct modinfo *modinfop)
99 {
100 	return (mod_info(&modlinkage, modinfop));
101 }
102 
103 /*
104  * N.B.
105  * No _fini routine. The module cannot be unloaded once loaded.
106  * The NO_UNLOAD_STUB in modstubs.s must change if this module
107  * is ever modified to become unloadable.
108  */
109 
110 int		nproc_highbit;		/* highbit(v.v_nproc) */
111 
112 static int	procfstype;
113 static major_t	procfs_major;
114 static minor_t	procfs_minor;
115 static kmutex_t	procfs_minor_lock;
116 
117 static kmutex_t	pr_mount_lock;
118 
119 /*
120  * /proc VFS operations vector.
121  */
122 static int	prmount(), prunmount(), prroot(), prstatvfs();
123 
124 static void
125 prinitrootnode(prnode_t *pnp, vfs_t *vfsp)
126 {
127 	struct vnode *vp;
128 
129 	bzero((caddr_t)pnp, sizeof (*pnp));
130 	pnp->pr_vnode = vp = vn_alloc(KM_SLEEP);
131 
132 	mutex_init(&pnp->pr_mutex, NULL, MUTEX_DEFAULT, NULL);
133 	vp->v_flag = VROOT|VNOCACHE|VNOMAP|VNOSWAP|VNOMOUNT;
134 	VN_SET_VFS_TYPE_DEV(vp, vfsp, VDIR, 0);
135 	vn_setops(vp, prvnodeops);
136 	vp->v_data = (caddr_t)pnp;
137 	pnp->pr_type = PR_PROCDIR;
138 	pnp->pr_mode = 0555;	/* read-search by everyone */
139 	vn_exists(vp);
140 }
141 
142 static int
143 prinit(int fstype, char *name)
144 {
145 	static const fs_operation_def_t pr_vfsops_template[] = {
146 		VFSNAME_MOUNT, prmount,
147 		VFSNAME_UNMOUNT, prunmount,
148 		VFSNAME_ROOT, prroot,
149 		VFSNAME_STATVFS, prstatvfs,
150 		NULL, NULL
151 	};
152 	extern const fs_operation_def_t pr_vnodeops_template[];
153 	int error;
154 
155 	nproc_highbit = highbit(v.v_proc);
156 	procfstype = fstype;
157 	ASSERT(procfstype != 0);
158 	/*
159 	 * Associate VFS ops vector with this fstype.
160 	 */
161 	error = vfs_setfsops(fstype, pr_vfsops_template, NULL);
162 	if (error != 0) {
163 		cmn_err(CE_WARN, "prinit: bad vfs ops template");
164 		return (error);
165 	}
166 
167 	/*
168 	 * Set up vnode ops vector too.
169 	 */
170 
171 	error = vn_make_ops(name, pr_vnodeops_template, &prvnodeops);
172 	if (error != 0) {
173 		(void) vfs_freevfsops_by_type(fstype);
174 		cmn_err(CE_WARN, "prinit: bad vnode ops template");
175 		return (error);
176 	}
177 
178 	/*
179 	 * Assign a unique "device" number (used by stat(2)).
180 	 */
181 	if ((procfs_major = getudev()) == (major_t)-1) {
182 		cmn_err(CE_WARN, "prinit: can't get unique device number");
183 		procfs_major = 0;
184 	}
185 	mutex_init(&pr_mount_lock, NULL, MUTEX_DEFAULT, NULL);
186 	mutex_init(&procfs_minor_lock, NULL, MUTEX_DEFAULT, NULL);
187 
188 	return (0);
189 }
190 
191 /* ARGSUSED */
192 static int
193 prmount(struct vfs *vfsp, struct vnode *mvp,
194 	struct mounta *uap, struct cred *cr)
195 {
196 	prnode_t *pnp;
197 	zone_t *zone = curproc->p_zone;
198 
199 	if (secpolicy_fs_mount(cr, mvp, vfsp) != 0)
200 		return (EPERM);
201 
202 	if (mvp->v_type != VDIR)
203 		return (ENOTDIR);
204 
205 	if (zone == global_zone) {
206 		zone_t *mntzone;
207 
208 		mntzone = zone_find_by_path(refstr_value(vfsp->vfs_mntpt));
209 		zone_rele(mntzone);
210 		if (zone != mntzone)
211 			return (EBUSY);
212 	}
213 	/*
214 	 * Having the resource be anything but "proc" doesn't make sense
215 	 */
216 	vfs_setresource(vfsp, "proc");
217 
218 	pnp = kmem_alloc(sizeof (*pnp), KM_SLEEP);
219 	mutex_enter(&pr_mount_lock);
220 
221 	mutex_enter(&mvp->v_lock);
222 	if ((uap->flags & MS_OVERLAY) == 0 &&
223 	    (mvp->v_count > 1 || (mvp->v_flag & VROOT))) {
224 		mutex_exit(&mvp->v_lock);
225 		mutex_exit(&pr_mount_lock);
226 		kmem_free(pnp, sizeof (*pnp));
227 		return (EBUSY);
228 	}
229 	mutex_exit(&mvp->v_lock);
230 
231 	prinitrootnode(pnp, vfsp);
232 	vfsp->vfs_fstype = procfstype;
233 	vfsp->vfs_data = (caddr_t)pnp;
234 	vfsp->vfs_bsize = DEV_BSIZE;
235 	/*
236 	 * find an available minor device number for this mount
237 	 */
238 	mutex_enter(&procfs_minor_lock);
239 	do {
240 		vfsp->vfs_dev = makedevice(procfs_major, procfs_minor);
241 		procfs_minor = (procfs_minor + 1) & L_MAXMIN32;
242 	} while (vfs_devismounted(vfsp->vfs_dev));
243 	mutex_exit(&procfs_minor_lock);
244 	vfs_make_fsid(&vfsp->vfs_fsid, vfsp->vfs_dev, procfstype);
245 
246 	mutex_exit(&pr_mount_lock);
247 	return (0);
248 }
249 
250 /* ARGSUSED */
251 static int
252 prunmount(struct vfs *vfsp, int flag, struct cred *cr)
253 {
254 	prnode_t *pnp = (prnode_t *)vfsp->vfs_data;
255 	vnode_t *vp = PTOV(pnp);
256 
257 	mutex_enter(&pr_mount_lock);
258 	if (secpolicy_fs_unmount(cr, vfsp) != 0) {
259 		mutex_exit(&pr_mount_lock);
260 		return (EPERM);
261 	}
262 
263 	/*
264 	 * forced unmount is not supported by this file system
265 	 * and thus, ENOTSUP, is being returned.
266 	 */
267 	if (flag & MS_FORCE) {
268 		mutex_exit(&pr_mount_lock);
269 		return (ENOTSUP);
270 	}
271 
272 	/*
273 	 * Ensure that no /proc vnodes are in use on this mount point.
274 	 */
275 	mutex_enter(&vp->v_lock);
276 	if (vp->v_count > 1) {
277 		mutex_exit(&vp->v_lock);
278 		mutex_exit(&pr_mount_lock);
279 		return (EBUSY);
280 	}
281 
282 	mutex_exit(&vp->v_lock);
283 	mutex_exit(&pr_mount_lock);
284 	vn_invalid(vp);
285 	vn_free(vp);
286 	kmem_free(pnp, sizeof (*pnp));
287 	return (0);
288 }
289 
290 /* ARGSUSED */
291 static int
292 prroot(struct vfs *vfsp, struct vnode **vpp)
293 {
294 	vnode_t *vp = PTOV((prnode_t *)vfsp->vfs_data);
295 
296 	VN_HOLD(vp);
297 	*vpp = vp;
298 	return (0);
299 }
300 
301 static int
302 prstatvfs(struct vfs *vfsp, struct statvfs64 *sp)
303 {
304 	int n;
305 	dev32_t d32;
306 	extern uint_t nproc;
307 
308 	n = v.v_proc - nproc;
309 
310 	bzero((caddr_t)sp, sizeof (*sp));
311 	sp->f_bsize	= DEV_BSIZE;
312 	sp->f_frsize	= DEV_BSIZE;
313 	sp->f_blocks	= (fsblkcnt64_t)0;
314 	sp->f_bfree	= (fsblkcnt64_t)0;
315 	sp->f_bavail	= (fsblkcnt64_t)0;
316 	sp->f_files	= (fsfilcnt64_t)v.v_proc + 2;
317 	sp->f_ffree	= (fsfilcnt64_t)n;
318 	sp->f_favail	= (fsfilcnt64_t)n;
319 	(void) cmpldev(&d32, vfsp->vfs_dev);
320 	sp->f_fsid	= d32;
321 	(void) strcpy(sp->f_basetype, vfssw[procfstype].vsw_name);
322 	sp->f_flag = vf_to_stf(vfsp->vfs_flag);
323 	sp->f_namemax = 64;		/* quite arbitrary */
324 	bzero(sp->f_fstr, sizeof (sp->f_fstr));
325 	(void) strcpy(sp->f_fstr, "/proc");
326 	(void) strcpy(&sp->f_fstr[6], "/proc");
327 	return (0);
328 }
329