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kernfs_vfsops.c revision 1.99 
      1 /*	$NetBSD: kernfs_vfsops.c,v 1.99 2020/03/16 21:20:11 pgoyette 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  *	@(#)kernfs_vfsops.c	8.10 (Berkeley) 5/14/95
     35  */
     36 
     37 /*
     38  * Kernel params Filesystem
     39  */
     40 
     41 #include <sys/cdefs.h>
     42 __KERNEL_RCSID(0, "$NetBSD: kernfs_vfsops.c,v 1.99 2020/03/16 21:20:11 pgoyette Exp $");
     43 
     44 #ifdef _KERNEL_OPT
     45 #include "opt_compat_netbsd.h"
     46 #endif
     47 
     48 #include <sys/param.h>
     49 #include <sys/systm.h>
     50 #include <sys/sysctl.h>
     51 #include <sys/conf.h>
     52 #include <sys/proc.h>
     53 #include <sys/vnode.h>
     54 #include <sys/mount.h>
     55 #include <sys/namei.h>
     56 #include <sys/dirent.h>
     57 #include <sys/malloc.h>
     58 #include <sys/syslog.h>
     59 #include <sys/kauth.h>
     60 #include <sys/module.h>
     61 
     62 #include <miscfs/genfs/genfs.h>
     63 #include <miscfs/specfs/specdev.h>
     64 #include <miscfs/kernfs/kernfs.h>
     65 
     66 MODULE(MODULE_CLASS_VFS, kernfs, NULL);
     67 
     68 MALLOC_JUSTDEFINE(M_KERNFSMNT, "kernfs mount", "kernfs mount structures");
     69 
     70 dev_t rrootdev = NODEV;
     71 kmutex_t kfs_lock;
     72 
     73 VFS_PROTOS(kernfs);
     74 
     75 void	kernfs_get_rrootdev(void);
     76 
     77 void
     78 kernfs_init(void)
     79 {
     80 
     81 	malloc_type_attach(M_KERNFSMNT);
     82 	mutex_init(&kfs_lock, MUTEX_DEFAULT, IPL_NONE);
     83 }
     84 
     85 void
     86 kernfs_reinit(void)
     87 {
     88 
     89 }
     90 
     91 void
     92 kernfs_done(void)
     93 {
     94 
     95 	mutex_destroy(&kfs_lock);
     96 	malloc_type_detach(M_KERNFSMNT);
     97 }
     98 
     99 void
    100 kernfs_get_rrootdev(void)
    101 {
    102 	static int tried = 0;
    103 
    104 	if (tried) {
    105 		/* Already did it once. */
    106 		return;
    107 	}
    108 	tried = 1;
    109 
    110 	if (rootdev == NODEV)
    111 		return;
    112 	rrootdev = devsw_blk2chr(rootdev);
    113 	if (rrootdev != NODEV)
    114 		return;
    115 	rrootdev = NODEV;
    116 	printf("kernfs_get_rrootdev: no raw root device\n");
    117 }
    118 
    119 /*
    120  * Mount the Kernel params filesystem
    121  */
    122 int
    123 kernfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len)
    124 {
    125 	struct lwp *l = curlwp;
    126 	int error = 0;
    127 	struct kernfs_mount *fmp;
    128 
    129 	if (UIO_MX & (UIO_MX - 1)) {
    130 		log(LOG_ERR, "kernfs: invalid directory entry size");
    131 		return (EINVAL);
    132 	}
    133 
    134 	if (mp->mnt_flag & MNT_GETARGS) {
    135 		*data_len = 0;
    136 		return 0;
    137 	}
    138 	/*
    139 	 * Update is a no-op
    140 	 */
    141 	if (mp->mnt_flag & MNT_UPDATE)
    142 		return (EOPNOTSUPP);
    143 
    144 	fmp = malloc(sizeof(struct kernfs_mount), M_KERNFSMNT, M_WAITOK|M_ZERO);
    145 	TAILQ_INIT(&fmp->nodelist);
    146 
    147 	mp->mnt_stat.f_namemax = KERNFS_MAXNAMLEN;
    148 	mp->mnt_flag |= MNT_LOCAL;
    149 	mp->mnt_data = fmp;
    150 	vfs_getnewfsid(mp);
    151 
    152 	if ((error = set_statvfs_info(path, UIO_USERSPACE, "kernfs",
    153 	    UIO_SYSSPACE, mp->mnt_op->vfs_name, mp, l)) != 0) {
    154 		free(fmp, M_KERNFSMNT);
    155 		return error;
    156 	}
    157 
    158 	kernfs_get_rrootdev();
    159 	return 0;
    160 }
    161 
    162 int
    163 kernfs_start(struct mount *mp, int flags)
    164 {
    165 
    166 	return (0);
    167 }
    168 
    169 int
    170 kernfs_unmount(struct mount *mp, int mntflags)
    171 {
    172 	int error;
    173 	int flags = 0;
    174 
    175 	if (mntflags & MNT_FORCE)
    176 		flags |= FORCECLOSE;
    177 
    178 	if ((error = vflush(mp, 0, flags)) != 0)
    179 		return (error);
    180 
    181 	/*
    182 	 * Finally, throw away the kernfs_mount structure
    183 	 */
    184 	free(mp->mnt_data, M_KERNFSMNT);
    185 	mp->mnt_data = NULL;
    186 	return (0);
    187 }
    188 
    189 int
    190 kernfs_root(struct mount *mp, int lktype, struct vnode **vpp)
    191 {
    192 	const struct kern_target *root_target = &kern_targets[0];
    193 	int error;
    194 
    195 	/* setup "." */
    196 	error = vcache_get(mp, &root_target, sizeof(root_target), vpp);
    197 	if (error)
    198 		return error;
    199 	error = vn_lock(*vpp, lktype);
    200 	if (error) {
    201 		vrele(*vpp);
    202 		*vpp = NULL;
    203 		return error;
    204 	}
    205 	return 0;
    206 }
    207 
    208 /*ARGSUSED*/
    209 int
    210 kernfs_sync(struct mount *mp, int waitfor,
    211     kauth_cred_t uc)
    212 {
    213 
    214 	return (0);
    215 }
    216 
    217 /*
    218  * Kernfs flat namespace lookup.
    219  * Currently unsupported.
    220  */
    221 int
    222 kernfs_vget(struct mount *mp, ino_t ino, int lktype,
    223     struct vnode **vpp)
    224 {
    225 
    226 	return (EOPNOTSUPP);
    227 }
    228 
    229 int
    230 kernfs_loadvnode(struct mount *mp, struct vnode *vp,
    231     const void *key, size_t key_len, const void **new_key)
    232 {
    233 	const struct kern_target *kt;
    234 	struct kernfs_node *kfs, *kfsp;
    235 	long *cookie;
    236 
    237 	KASSERT(key_len == sizeof(kt));
    238 	memcpy(&kt, key, key_len);
    239 
    240 	kfs = kmem_zalloc(sizeof(struct kernfs_node), KM_SLEEP);
    241 	cookie = &(VFSTOKERNFS(mp)->fileno_cookie);
    242 	mutex_enter(&kfs_lock);
    243 again:
    244 	TAILQ_FOREACH(kfsp, &VFSTOKERNFS(mp)->nodelist, kfs_list) {
    245 		if (kfsp->kfs_cookie == *cookie) {
    246 			(*cookie) ++;
    247 			goto again;
    248 		}
    249 		if (TAILQ_NEXT(kfsp, kfs_list)) {
    250 			if (kfsp->kfs_cookie < *cookie &&
    251 			    *cookie < TAILQ_NEXT(kfsp, kfs_list)->kfs_cookie)
    252 				break;
    253 			if (kfsp->kfs_cookie + 1 <
    254 			    TAILQ_NEXT(kfsp, kfs_list)->kfs_cookie) {
    255 				*cookie = kfsp->kfs_cookie + 1;
    256 				break;
    257 			}
    258 		}
    259 	}
    260 
    261 	kfs->kfs_cookie = *cookie;
    262 
    263 	if (kfsp)
    264 		TAILQ_INSERT_AFTER(&VFSTOKERNFS(mp)->nodelist, kfsp, kfs,
    265 		    kfs_list);
    266 	else
    267 		TAILQ_INSERT_TAIL(&VFSTOKERNFS(mp)->nodelist, kfs, kfs_list);
    268 
    269 	kfs->kfs_type = kt->kt_tag;
    270 	kfs->kfs_vnode = vp;
    271 	kfs->kfs_fileno = KERNFS_FILENO(kt, kt->kt_tag, kfs->kfs_cookie);
    272 	kfs->kfs_kt = kt;
    273 	kfs->kfs_mode = kt->kt_mode;
    274 	vp->v_tag = VT_KERNFS;
    275 	vp->v_op = kernfs_vnodeop_p;
    276 	vp->v_data = kfs;
    277 	vp->v_type = kt->kt_vtype;
    278 	mutex_exit(&kfs_lock);
    279 
    280 	if (kt->kt_tag == KFSkern)
    281 		vp->v_vflag = VV_ROOT;
    282 
    283 	if (kt->kt_tag == KFSdevice) {
    284 		vp->v_op = kernfs_specop_p;
    285 		spec_node_init(vp, *(dev_t *)kt->kt_data);
    286 	}
    287 
    288 	uvm_vnp_setsize(vp, 0);
    289 
    290 	*new_key = &kfs->kfs_kt;
    291 	return 0;
    292 }
    293 
    294 extern const struct vnodeopv_desc kernfs_vnodeop_opv_desc;
    295 extern const struct vnodeopv_desc kernfs_specop_opv_desc;
    296 
    297 const struct vnodeopv_desc * const kernfs_vnodeopv_descs[] = {
    298 	&kernfs_vnodeop_opv_desc,
    299 	&kernfs_specop_opv_desc,
    300 	NULL,
    301 };
    302 
    303 struct vfsops kernfs_vfsops = {
    304 	.vfs_name = MOUNT_KERNFS,
    305 	.vfs_min_mount_data = 0,
    306 	.vfs_mount = kernfs_mount,
    307 	.vfs_start = kernfs_start,
    308 	.vfs_unmount = kernfs_unmount,
    309 	.vfs_root = kernfs_root,
    310 	.vfs_quotactl = (void *)eopnotsupp,
    311 	.vfs_statvfs = genfs_statvfs,
    312 	.vfs_sync = kernfs_sync,
    313 	.vfs_vget = kernfs_vget,
    314 	.vfs_loadvnode = kernfs_loadvnode,
    315 	.vfs_fhtovp = (void *)eopnotsupp,
    316 	.vfs_vptofh = (void *)eopnotsupp,
    317 	.vfs_init = kernfs_init,
    318 	.vfs_reinit = kernfs_reinit,
    319 	.vfs_done = kernfs_done,
    320 	.vfs_snapshot = (void *)eopnotsupp,
    321 	.vfs_extattrctl = vfs_stdextattrctl,
    322 	.vfs_suspendctl = genfs_suspendctl,
    323 	.vfs_renamelock_enter = genfs_renamelock_enter,
    324 	.vfs_renamelock_exit = genfs_renamelock_exit,
    325 	.vfs_fsync = (void *)eopnotsupp,
    326 	.vfs_opv_descs = kernfs_vnodeopv_descs
    327 };
    328 
    329 SYSCTL_SETUP(kernfs_sysctl_setup, "kernfs sysctl")
    330 {
    331 
    332 	sysctl_createv(clog, 0, NULL, NULL,
    333 		       CTLFLAG_PERMANENT,
    334 		       CTLTYPE_NODE, "kernfs",
    335 		       SYSCTL_DESCR("/kern file system"),
    336 		       NULL, 0, NULL, 0,
    337 		       CTL_VFS, 11, CTL_EOL);
    338 	/*
    339 	 * XXX the "11" above could be dynamic, thereby eliminating one
    340 	 * more instance of the "number to vfs" mapping problem, but
    341 	 * "11" is the order as taken from sys/mount.h
    342 	 */
    343 }
    344 
    345 static int
    346 kernfs_modcmd(modcmd_t cmd, void *arg)
    347 {
    348 	int error;
    349 
    350 	switch (cmd) {
    351 	case MODULE_CMD_INIT:
    352 		error = vfs_attach(&kernfs_vfsops);
    353 		if (error != 0)
    354 			break;
    355 		break;
    356 	case MODULE_CMD_FINI:
    357 		error = vfs_detach(&kernfs_vfsops);
    358 		if (error != 0)
    359 			break;
    360 		break;
    361 	default:
    362 		error = ENOTTY;
    363 		break;
    364 	}
    365 
    366 	return (error);
    367 }
    368