xref: /netbsd-src/sys/miscfs/kernfs/kernfs_vfsops.c (revision 8d1e4d9c00546fbb58984e59c6a82d1e598f3c27)
1*8d1e4d9cSjdolecek /*	$NetBSD: kernfs_vfsops.c,v 1.100 2020/04/07 08:35:49 jdolecek Exp $	*/
2cf92afd6Scgd 
3fa8ba8a3Scgd /*
4e5bc90f4Sfvdl  * Copyright (c) 1992, 1993, 1995
5cde1d475Smycroft  *	The Regents of the University of California.  All rights reserved.
6fa8ba8a3Scgd  *
787693669Scgd  * This code is derived from software donated to Berkeley by
8fa8ba8a3Scgd  * Jan-Simon Pendry.
9fa8ba8a3Scgd  *
10320661fcScgd  * Redistribution and use in source and binary forms, with or without
11320661fcScgd  * modification, are permitted provided that the following conditions
12320661fcScgd  * are met:
13320661fcScgd  * 1. Redistributions of source code must retain the above copyright
14320661fcScgd  *    notice, this list of conditions and the following disclaimer.
15320661fcScgd  * 2. Redistributions in binary form must reproduce the above copyright
16320661fcScgd  *    notice, this list of conditions and the following disclaimer in the
17320661fcScgd  *    documentation and/or other materials provided with the distribution.
18aad01611Sagc  * 3. Neither the name of the University nor the names of its contributors
19320661fcScgd  *    may be used to endorse or promote products derived from this software
20320661fcScgd  *    without specific prior written permission.
21fa8ba8a3Scgd  *
22320661fcScgd  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23320661fcScgd  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24320661fcScgd  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25320661fcScgd  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26320661fcScgd  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27320661fcScgd  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28320661fcScgd  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29320661fcScgd  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30320661fcScgd  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31320661fcScgd  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32320661fcScgd  * SUCH DAMAGE.
33fa8ba8a3Scgd  *
34e5bc90f4Sfvdl  *	@(#)kernfs_vfsops.c	8.10 (Berkeley) 5/14/95
35fa8ba8a3Scgd  */
36fa8ba8a3Scgd 
37fa8ba8a3Scgd /*
38fa8ba8a3Scgd  * Kernel params Filesystem
39fa8ba8a3Scgd  */
40fa8ba8a3Scgd 
41e4b00f43Slukem #include <sys/cdefs.h>
42*8d1e4d9cSjdolecek __KERNEL_RCSID(0, "$NetBSD: kernfs_vfsops.c,v 1.100 2020/04/07 08:35:49 jdolecek Exp $");
43e4b00f43Slukem 
448ca90bd4Sitojun #ifdef _KERNEL_OPT
45d275e56dSjonathan #include "opt_compat_netbsd.h"
46d275e56dSjonathan #endif
47d275e56dSjonathan 
480560892dSmycroft #include <sys/param.h>
490560892dSmycroft #include <sys/systm.h>
5013f8d2ceSatatat #include <sys/sysctl.h>
51cde1d475Smycroft #include <sys/conf.h>
520560892dSmycroft #include <sys/proc.h>
530560892dSmycroft #include <sys/vnode.h>
540560892dSmycroft #include <sys/mount.h>
550560892dSmycroft #include <sys/namei.h>
5690345b38Schristos #include <sys/dirent.h>
578ca90bd4Sitojun #include <sys/syslog.h>
58fc9422c9Selad #include <sys/kauth.h>
59a1221b6dSrumble #include <sys/module.h>
60cde1d475Smycroft 
61717e1785Sdholland #include <miscfs/genfs/genfs.h>
62cde1d475Smycroft #include <miscfs/specfs/specdev.h>
630560892dSmycroft #include <miscfs/kernfs/kernfs.h>
64fa8ba8a3Scgd 
65a1221b6dSrumble MODULE(MODULE_CLASS_VFS, kernfs, NULL);
66a1221b6dSrumble 
67cde1d475Smycroft dev_t rrootdev = NODEV;
6898fe1e89Shannken kmutex_t kfs_lock;
69cde1d475Smycroft 
708d1f8992Spooka VFS_PROTOS(kernfs);
718d1f8992Spooka 
72af97f2e8Sxtraeme void	kernfs_get_rrootdev(void);
73631ccba6Schristos 
74631ccba6Schristos void
kernfs_init(void)75b8817e4aScegger kernfs_init(void)
76fa8ba8a3Scgd {
77835b0326Spooka 
7898fe1e89Shannken 	mutex_init(&kfs_lock, MUTEX_DEFAULT, IPL_NONE);
798ca90bd4Sitojun }
808ca90bd4Sitojun 
818ca90bd4Sitojun void
kernfs_reinit(void)82b8817e4aScegger kernfs_reinit(void)
838ca90bd4Sitojun {
8498fe1e89Shannken 
8586f96020Scgd }
8686f96020Scgd 
8787693669Scgd void
kernfs_done(void)88b8817e4aScegger kernfs_done(void)
8989015c46Sjdolecek {
90835b0326Spooka 
9198fe1e89Shannken 	mutex_destroy(&kfs_lock);
9289015c46Sjdolecek }
9389015c46Sjdolecek 
9489015c46Sjdolecek void
kernfs_get_rrootdev(void)95b8817e4aScegger kernfs_get_rrootdev(void)
9686f96020Scgd {
972e6e470fSmycroft 	static int tried = 0;
9886f96020Scgd 
992e6e470fSmycroft 	if (tried) {
100cde1d475Smycroft 		/* Already did it once. */
101cde1d475Smycroft 		return;
102cde1d475Smycroft 	}
1032e6e470fSmycroft 	tried = 1;
1042e6e470fSmycroft 
1052e6e470fSmycroft 	if (rootdev == NODEV)
1062e6e470fSmycroft 		return;
10777a6b82bSgehenna 	rrootdev = devsw_blk2chr(rootdev);
1088ca90bd4Sitojun 	if (rrootdev != NODEV)
10986f96020Scgd 		return;
1102e6e470fSmycroft 	rrootdev = NODEV;
11192a808f1Schristos 	printf("kernfs_get_rrootdev: no raw root device\n");
112b9a4c9fcScgd }
113fa8ba8a3Scgd 
114fa8ba8a3Scgd /*
115cde1d475Smycroft  * Mount the Kernel params filesystem
116fa8ba8a3Scgd  */
117631ccba6Schristos int
kernfs_mount(struct mount * mp,const char * path,void * data,size_t * data_len)11861e8303eSpooka kernfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len)
119fa8ba8a3Scgd {
12061e8303eSpooka 	struct lwp *l = curlwp;
121fa8ba8a3Scgd 	int error = 0;
122fa8ba8a3Scgd 	struct kernfs_mount *fmp;
123fa8ba8a3Scgd 
1248ca90bd4Sitojun 	if (UIO_MX & (UIO_MX - 1)) {
1258ca90bd4Sitojun 		log(LOG_ERR, "kernfs: invalid directory entry size");
1268ca90bd4Sitojun 		return (EINVAL);
1278ca90bd4Sitojun 	}
128fa8ba8a3Scgd 
1292721ab6cSdsl 	if (mp->mnt_flag & MNT_GETARGS) {
1302721ab6cSdsl 		*data_len = 0;
1316868d0a7Schristos 		return 0;
1322721ab6cSdsl 	}
133fa8ba8a3Scgd 	/*
134fa8ba8a3Scgd 	 * Update is a no-op
135fa8ba8a3Scgd 	 */
136fa8ba8a3Scgd 	if (mp->mnt_flag & MNT_UPDATE)
137fa8ba8a3Scgd 		return (EOPNOTSUPP);
138fa8ba8a3Scgd 
139*8d1e4d9cSjdolecek 	fmp = kmem_zalloc(sizeof(struct kernfs_mount), KM_SLEEP);
1408ca90bd4Sitojun 	TAILQ_INIT(&fmp->nodelist);
1418ca90bd4Sitojun 
142a3c05018Schristos 	mp->mnt_stat.f_namemax = KERNFS_MAXNAMLEN;
1438ca90bd4Sitojun 	mp->mnt_flag |= MNT_LOCAL;
1442993272aSjdolecek 	mp->mnt_data = fmp;
1456c734cd2Sassar 	vfs_getnewfsid(mp);
146fa8ba8a3Scgd 
1471db853aaStron 	if ((error = set_statvfs_info(path, UIO_USERSPACE, "kernfs",
148e24b0872Spooka 	    UIO_SYSSPACE, mp->mnt_op->vfs_name, mp, l)) != 0) {
149*8d1e4d9cSjdolecek 		kmem_free(fmp, sizeof(struct kernfs_mount));
1501db853aaStron 		return error;
1511db853aaStron 	}
15286f96020Scgd 
153cde1d475Smycroft 	kernfs_get_rrootdev();
1541db853aaStron 	return 0;
155fa8ba8a3Scgd }
156fa8ba8a3Scgd 
157631ccba6Schristos int
kernfs_start(struct mount * mp,int flags)15861e8303eSpooka kernfs_start(struct mount *mp, int flags)
159fa8ba8a3Scgd {
160cde1d475Smycroft 
161fa8ba8a3Scgd 	return (0);
162fa8ba8a3Scgd }
163fa8ba8a3Scgd 
164631ccba6Schristos int
kernfs_unmount(struct mount * mp,int mntflags)16561e8303eSpooka kernfs_unmount(struct mount *mp, int mntflags)
166fa8ba8a3Scgd {
167fa8ba8a3Scgd 	int error;
168fa8ba8a3Scgd 	int flags = 0;
169fa8ba8a3Scgd 
170e5bc90f4Sfvdl 	if (mntflags & MNT_FORCE)
171fa8ba8a3Scgd 		flags |= FORCECLOSE;
172fa8ba8a3Scgd 
1738ca90bd4Sitojun 	if ((error = vflush(mp, 0, flags)) != 0)
174fa8ba8a3Scgd 		return (error);
175fa8ba8a3Scgd 
176fa8ba8a3Scgd 	/*
177fa8ba8a3Scgd 	 * Finally, throw away the kernfs_mount structure
178fa8ba8a3Scgd 	 */
179*8d1e4d9cSjdolecek 	kmem_free(mp->mnt_data, sizeof(struct kernfs_mount));
1801db853aaStron 	mp->mnt_data = NULL;
181cde1d475Smycroft 	return (0);
182fa8ba8a3Scgd }
183fa8ba8a3Scgd 
184631ccba6Schristos int
kernfs_root(struct mount * mp,int lktype,struct vnode ** vpp)185c2e9cb94Sad kernfs_root(struct mount *mp, int lktype, struct vnode **vpp)
186fa8ba8a3Scgd {
18798fe1e89Shannken 	const struct kern_target *root_target = &kern_targets[0];
18898fe1e89Shannken 	int error;
189fa8ba8a3Scgd 
1908ca90bd4Sitojun 	/* setup "." */
19198fe1e89Shannken 	error = vcache_get(mp, &root_target, sizeof(root_target), vpp);
19298fe1e89Shannken 	if (error)
19398fe1e89Shannken 		return error;
194c2e9cb94Sad 	error = vn_lock(*vpp, lktype);
19598fe1e89Shannken 	if (error) {
19698fe1e89Shannken 		vrele(*vpp);
19798fe1e89Shannken 		*vpp = NULL;
19898fe1e89Shannken 		return error;
19998fe1e89Shannken 	}
20098fe1e89Shannken 	return 0;
201fa8ba8a3Scgd }
202fa8ba8a3Scgd 
203631ccba6Schristos /*ARGSUSED*/
204631ccba6Schristos int
kernfs_sync(struct mount * mp,int waitfor,kauth_cred_t uc)205168cd830Schristos kernfs_sync(struct mount *mp, int waitfor,
20661e8303eSpooka     kauth_cred_t uc)
207fa8ba8a3Scgd {
208cde1d475Smycroft 
209fa8ba8a3Scgd 	return (0);
210fa8ba8a3Scgd }
211fa8ba8a3Scgd 
212cde1d475Smycroft /*
213cde1d475Smycroft  * Kernfs flat namespace lookup.
214cde1d475Smycroft  * Currently unsupported.
215cde1d475Smycroft  */
216631ccba6Schristos int
kernfs_vget(struct mount * mp,ino_t ino,int lktype,struct vnode ** vpp)217c2e9cb94Sad kernfs_vget(struct mount *mp, ino_t ino, int lktype,
218168cd830Schristos     struct vnode **vpp)
219fa8ba8a3Scgd {
220cde1d475Smycroft 
221cde1d475Smycroft 	return (EOPNOTSUPP);
222cde1d475Smycroft }
223cde1d475Smycroft 
22498fe1e89Shannken int
kernfs_loadvnode(struct mount * mp,struct vnode * vp,const void * key,size_t key_len,const void ** new_key)22598fe1e89Shannken kernfs_loadvnode(struct mount *mp, struct vnode *vp,
22698fe1e89Shannken     const void *key, size_t key_len, const void **new_key)
22798fe1e89Shannken {
22898fe1e89Shannken 	const struct kern_target *kt;
22998fe1e89Shannken 	struct kernfs_node *kfs, *kfsp;
23098fe1e89Shannken 	long *cookie;
23198fe1e89Shannken 
23298fe1e89Shannken 	KASSERT(key_len == sizeof(kt));
23398fe1e89Shannken 	memcpy(&kt, key, key_len);
23498fe1e89Shannken 
23598fe1e89Shannken 	kfs = kmem_zalloc(sizeof(struct kernfs_node), KM_SLEEP);
23698fe1e89Shannken 	cookie = &(VFSTOKERNFS(mp)->fileno_cookie);
23798fe1e89Shannken 	mutex_enter(&kfs_lock);
23898fe1e89Shannken again:
23998fe1e89Shannken 	TAILQ_FOREACH(kfsp, &VFSTOKERNFS(mp)->nodelist, kfs_list) {
24098fe1e89Shannken 		if (kfsp->kfs_cookie == *cookie) {
24198fe1e89Shannken 			(*cookie) ++;
24298fe1e89Shannken 			goto again;
24398fe1e89Shannken 		}
24498fe1e89Shannken 		if (TAILQ_NEXT(kfsp, kfs_list)) {
24598fe1e89Shannken 			if (kfsp->kfs_cookie < *cookie &&
24698fe1e89Shannken 			    *cookie < TAILQ_NEXT(kfsp, kfs_list)->kfs_cookie)
24798fe1e89Shannken 				break;
24898fe1e89Shannken 			if (kfsp->kfs_cookie + 1 <
24998fe1e89Shannken 			    TAILQ_NEXT(kfsp, kfs_list)->kfs_cookie) {
25098fe1e89Shannken 				*cookie = kfsp->kfs_cookie + 1;
25198fe1e89Shannken 				break;
25298fe1e89Shannken 			}
25398fe1e89Shannken 		}
25498fe1e89Shannken 	}
25598fe1e89Shannken 
25698fe1e89Shannken 	kfs->kfs_cookie = *cookie;
25798fe1e89Shannken 
25898fe1e89Shannken 	if (kfsp)
25998fe1e89Shannken 		TAILQ_INSERT_AFTER(&VFSTOKERNFS(mp)->nodelist, kfsp, kfs,
26098fe1e89Shannken 		    kfs_list);
26198fe1e89Shannken 	else
26298fe1e89Shannken 		TAILQ_INSERT_TAIL(&VFSTOKERNFS(mp)->nodelist, kfs, kfs_list);
26398fe1e89Shannken 
26498fe1e89Shannken 	kfs->kfs_type = kt->kt_tag;
26598fe1e89Shannken 	kfs->kfs_vnode = vp;
26698fe1e89Shannken 	kfs->kfs_fileno = KERNFS_FILENO(kt, kt->kt_tag, kfs->kfs_cookie);
26798fe1e89Shannken 	kfs->kfs_kt = kt;
26898fe1e89Shannken 	kfs->kfs_mode = kt->kt_mode;
26998fe1e89Shannken 	vp->v_tag = VT_KERNFS;
27098fe1e89Shannken 	vp->v_op = kernfs_vnodeop_p;
27198fe1e89Shannken 	vp->v_data = kfs;
27298fe1e89Shannken 	vp->v_type = kt->kt_vtype;
27398fe1e89Shannken 	mutex_exit(&kfs_lock);
27498fe1e89Shannken 
27598fe1e89Shannken 	if (kt->kt_tag == KFSkern)
27698fe1e89Shannken 		vp->v_vflag = VV_ROOT;
27798fe1e89Shannken 
27898fe1e89Shannken 	if (kt->kt_tag == KFSdevice) {
279b26fba76Sriastradh 		vp->v_op = kernfs_specop_p;
28098fe1e89Shannken 		spec_node_init(vp, *(dev_t *)kt->kt_data);
28198fe1e89Shannken 	}
28298fe1e89Shannken 
28398fe1e89Shannken 	uvm_vnp_setsize(vp, 0);
28498fe1e89Shannken 
28598fe1e89Shannken 	*new_key = &kfs->kfs_kt;
28698fe1e89Shannken 	return 0;
28798fe1e89Shannken }
28898fe1e89Shannken 
289d9466585Sjdolecek extern const struct vnodeopv_desc kernfs_vnodeop_opv_desc;
290b26fba76Sriastradh extern const struct vnodeopv_desc kernfs_specop_opv_desc;
291b5bf2ed6Sthorpej 
292d9466585Sjdolecek const struct vnodeopv_desc * const kernfs_vnodeopv_descs[] = {
293b5bf2ed6Sthorpej 	&kernfs_vnodeop_opv_desc,
294b26fba76Sriastradh 	&kernfs_specop_opv_desc,
295b5bf2ed6Sthorpej 	NULL,
296b5bf2ed6Sthorpej };
297b5bf2ed6Sthorpej 
298fa8ba8a3Scgd struct vfsops kernfs_vfsops = {
2996d285189Shannken 	.vfs_name = MOUNT_KERNFS,
3006d285189Shannken 	.vfs_min_mount_data = 0,
3016d285189Shannken 	.vfs_mount = kernfs_mount,
3026d285189Shannken 	.vfs_start = kernfs_start,
3036d285189Shannken 	.vfs_unmount = kernfs_unmount,
3046d285189Shannken 	.vfs_root = kernfs_root,
3056d285189Shannken 	.vfs_quotactl = (void *)eopnotsupp,
3066d285189Shannken 	.vfs_statvfs = genfs_statvfs,
3076d285189Shannken 	.vfs_sync = kernfs_sync,
3086d285189Shannken 	.vfs_vget = kernfs_vget,
30998fe1e89Shannken 	.vfs_loadvnode = kernfs_loadvnode,
3106d285189Shannken 	.vfs_fhtovp = (void *)eopnotsupp,
3116d285189Shannken 	.vfs_vptofh = (void *)eopnotsupp,
3126d285189Shannken 	.vfs_init = kernfs_init,
3136d285189Shannken 	.vfs_reinit = kernfs_reinit,
3146d285189Shannken 	.vfs_done = kernfs_done,
3156d285189Shannken 	.vfs_snapshot = (void *)eopnotsupp,
3166d285189Shannken 	.vfs_extattrctl = vfs_stdextattrctl,
317326db3aaShannken 	.vfs_suspendctl = genfs_suspendctl,
3186d285189Shannken 	.vfs_renamelock_enter = genfs_renamelock_enter,
3196d285189Shannken 	.vfs_renamelock_exit = genfs_renamelock_exit,
3206d285189Shannken 	.vfs_fsync = (void *)eopnotsupp,
3216d285189Shannken 	.vfs_opv_descs = kernfs_vnodeopv_descs
322fa8ba8a3Scgd };
323a1221b6dSrumble 
3249120d451Spgoyette SYSCTL_SETUP(kernfs_sysctl_setup, "kernfs sysctl")
325a1221b6dSrumble {
326a1221b6dSrumble 
3279120d451Spgoyette 	sysctl_createv(clog, 0, NULL, NULL,
32828f5ebd8Srumble 		       CTLFLAG_PERMANENT,
32928f5ebd8Srumble 		       CTLTYPE_NODE, "kernfs",
33028f5ebd8Srumble 		       SYSCTL_DESCR("/kern file system"),
33128f5ebd8Srumble 		       NULL, 0, NULL, 0,
33228f5ebd8Srumble 		       CTL_VFS, 11, CTL_EOL);
33328f5ebd8Srumble 	/*
33428f5ebd8Srumble 	 * XXX the "11" above could be dynamic, thereby eliminating one
33528f5ebd8Srumble 	 * more instance of the "number to vfs" mapping problem, but
33628f5ebd8Srumble 	 * "11" is the order as taken from sys/mount.h
33728f5ebd8Srumble 	 */
3389120d451Spgoyette }
3399120d451Spgoyette 
3409120d451Spgoyette static int
kernfs_modcmd(modcmd_t cmd,void * arg)3419120d451Spgoyette kernfs_modcmd(modcmd_t cmd, void *arg)
3429120d451Spgoyette {
3439120d451Spgoyette 	int error;
3449120d451Spgoyette 
3459120d451Spgoyette 	switch (cmd) {
3469120d451Spgoyette 	case MODULE_CMD_INIT:
3479120d451Spgoyette 		error = vfs_attach(&kernfs_vfsops);
3489120d451Spgoyette 		if (error != 0)
3499120d451Spgoyette 			break;
35028f5ebd8Srumble 		break;
351a1221b6dSrumble 	case MODULE_CMD_FINI:
35228f5ebd8Srumble 		error = vfs_detach(&kernfs_vfsops);
35328f5ebd8Srumble 		if (error != 0)
35428f5ebd8Srumble 			break;
35528f5ebd8Srumble 		break;
356a1221b6dSrumble 	default:
35728f5ebd8Srumble 		error = ENOTTY;
35828f5ebd8Srumble 		break;
359a1221b6dSrumble 	}
36028f5ebd8Srumble 
36128f5ebd8Srumble 	return (error);
362a1221b6dSrumble }
363