kernfs_vnops.c

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/*
 * Copyright (c) 1992, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software donated to Berkeley by
 * Jan-Simon Pendry.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	@(#)kernfs_vnops.c	8.6 (Berkeley) 2/10/94
 */

/*
 * Kernel parameter filesystem (/kern)
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/vmmeter.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/proc.h>
#include <sys/vnode.h>
#include <sys/malloc.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/buf.h>
#include <sys/dirent.h>
#include <miscfs/kernfs/kernfs.h>

#define KSTRING	256		/* Largest I/O available via this filesystem */
#define	UIO_MX 32

#define	READ_MODE	(S_IRUSR|S_IRGRP|S_IROTH)
#define	WRITE_MODE	(S_IWUSR|S_IRUSR|S_IRGRP|S_IROTH)
#define DIR_MODE	(S_IRUSR|S_IXUSR|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH)

struct kern_target {
	char *kt_name;
	void *kt_data;
#define	KTT_NULL 1
#define	KTT_TIME 5
#define KTT_INT	17
#define	KTT_STRING 31
#define KTT_HOSTNAME 47
#define KTT_AVENRUN 53
	int kt_tag;
	int kt_rw;
	int kt_vtype;
} kern_targets[] = {
/* NOTE: The name must be less than UIO_MX-16 chars in length */
	/* name		data		tag		ro/rw */
	{ ".",		0,		KTT_NULL,	VREAD,		VDIR },
	{ "..",		0,		KTT_NULL,	VREAD,		VDIR },
	{ "boottime",	&boottime.tv_sec, KTT_INT,	VREAD,		VREG },
	{ "copyright",	copyright,	KTT_STRING,	VREAD,		VREG },
	{ "hostname",	0,		KTT_HOSTNAME,	VREAD|VWRITE,	VREG },
	{ "hz",		&hz,		KTT_INT,	VREAD,		VREG },
	{ "loadavg",	0,		KTT_AVENRUN,	VREAD,		VREG },
	{ "pagesize",	&cnt.v_page_size, KTT_INT,	VREAD,		VREG },
	{ "physmem",	&physmem,	KTT_INT,	VREAD,		VREG },
#if 0
	{ "root",	0,		KTT_NULL,	VREAD,		VDIR },
#endif
	{ "rootdev",	0,		KTT_NULL,	VREAD,		VBLK },
	{ "rrootdev",	0,		KTT_NULL,	VREAD,		VCHR },
	{ "time",	0,		KTT_TIME,	VREAD,		VREG },
	{ "version",	version,	KTT_STRING,	VREAD,		VREG },
};

static int nkern_targets = sizeof(kern_targets) / sizeof(kern_targets[0]);

static int
kernfs_xread(kt, buf, len, lenp)
	struct kern_target *kt;
	char *buf;
	int len;
	int *lenp;
{
	switch (kt->kt_tag) {
	case KTT_TIME: {
		struct timeval tv;
		microtime(&tv);
		sprintf(buf, "%d %d\n", tv.tv_sec, tv.tv_usec);
		break;
	}

	case KTT_INT: {
		int *ip = kt->kt_data;
		sprintf(buf, "%d\n", *ip);
		break;
	}

	case KTT_STRING: {
		char *cp = kt->kt_data;
		int xlen = strlen(cp) + 1;

		if (xlen >= len)
			return (EINVAL);

		bcopy(cp, buf, xlen);
		break;
	}

	case KTT_HOSTNAME: {
		char *cp = hostname;
		int xlen = hostnamelen;

		if (xlen >= (len-2))
			return (EINVAL);

		bcopy(cp, buf, xlen);
		buf[xlen] = '\n';
		buf[xlen+1] = '\0';
		break;
	}

	case KTT_AVENRUN:
		sprintf(buf, "%ld %ld %ld %ld\n",
				averunnable.ldavg[0],
				averunnable.ldavg[1],
				averunnable.ldavg[2],
				averunnable.fscale);
		break;

	default:
		return (EINVAL);
	}

	*lenp = strlen(buf);
	return (0);
}

static int
kernfs_xwrite(kt, buf, len)
	struct kern_target *kt;
	char *buf;
	int len;
{
	switch (kt->kt_tag) {
	case KTT_HOSTNAME: {
		if (buf[len-1] == '\n')
			--len;
		bcopy(buf, hostname, len);
		hostname[len] = '\0';
		hostnamelen = len;
		return (0);
	}

	default:
		return (EIO);
	}
}


/*
 * vp is the current namei directory
 * ndp is the name to locate in that directory...
 */
kernfs_lookup(ap)
	struct vop_lookup_args /* {
		struct vnode * a_dvp;
		struct vnode ** a_vpp;
		struct componentname * a_cnp;
	} */ *ap;
{
	struct vnode **vpp = ap->a_vpp;
	struct vnode *dvp = ap->a_dvp;
	struct componentname *cnp = ap->a_cnp;
	struct vnode *fvp;
	int error, i;
	char *pname;

#ifdef KERNFS_DIAGNOSTIC
	printf("kernfs_lookup(%x)\n", ap);
	printf("kernfs_lookup(dp = %x, vpp = %x, cnp = %x)\n", dvp, vpp, ap->a_cnp);
#endif
	pname = cnp->cn_nameptr;
#ifdef KERNFS_DIAGNOSTIC
	printf("kernfs_lookup(%s)\n", pname);
#endif
	if (cnp->cn_namelen == 1 && *pname == '.') {
		*vpp = dvp;
		VREF(dvp);
		/*VOP_LOCK(dvp);*/
		return (0);
	}

#if 0
	if (cnp->cn_namelen == 4 && bcmp(pname, "root", 4) == 0) {
		*vpp = rootdir;
		VREF(rootdir);
		VOP_LOCK(rootdir);
		return (0);
	}
#endif

	/*
	 * /kern/rootdev is the root device
	 */
	if (cnp->cn_namelen == 7 && bcmp(pname, "rootdev", 7) == 0) {
		*vpp = rootvp;
		VREF(rootvp);
		VOP_LOCK(rootvp);
		return (0);
	}

	/*
	 * /kern/rrootdev is the raw root device
	 */
	if (cnp->cn_namelen == 8 && bcmp(pname, "rrootdev", 8) == 0) {
		if (rrootvp) {
			*vpp = rrootvp;
			VREF(rrootvp);
			VOP_LOCK(rrootvp);
			return (0);
		}
		error = ENXIO;
		goto bad;
	}

	error = ENOENT;

	for (i = 0; i < nkern_targets; i++) {
		struct kern_target *kt = &kern_targets[i];
		if (cnp->cn_namelen == strlen(kt->kt_name) &&
		    bcmp(kt->kt_name, pname, cnp->cn_namelen) == 0) {
			error = 0;
			break;
		}
	}

#ifdef KERNFS_DIAGNOSTIC
	printf("kernfs_lookup: i = %d, error = %d\n", i, error);
#endif

	if (error)
		goto bad;

#ifdef KERNFS_DIAGNOSTIC
	printf("kernfs_lookup: allocate new vnode\n");
#endif
	error = getnewvnode(VT_KERNFS, dvp->v_mount, kernfs_vnodeop_p, &fvp);
	if (error)
		goto bad;
	MALLOC(fvp->v_data, void *, sizeof(struct kernfs_node), M_TEMP, M_WAITOK);
	VTOKERN(fvp)->kf_kt = &kern_targets[i];
	fvp->v_type = VTOKERN(fvp)->kf_kt->kt_vtype;
	*vpp = fvp;
#ifdef KERNFS_DIAGNOSTIC
	printf("kernfs_lookup: newvp = %x\n", fvp);
#endif
	return (0);

bad:;
	*vpp = NULL;
#ifdef KERNFS_DIAGNOSTIC
	printf("kernfs_lookup: error = %d\n", error);
#endif
	return (error);
}

kernfs_open(ap)
	struct vop_open_args /* {
		struct vnode *a_vp;
		int  a_mode;
		struct ucred *a_cred;
		struct proc *a_p;
	} */ *ap;
{
	struct vnode *vp = ap->a_vp;

	/*
	 * Can always open the root (modulo perms)
	 */
	if (vp->v_flag & VROOT)
		return (0);

#ifdef KERNFS_DIAGNOSTIC
	printf("kernfs_open, mode = %x, file = %s\n",
			ap->a_mode, VTOKERN(vp)->kf_kt->kt_name);
#endif

	if ((ap->a_mode & FWRITE) && !(VTOKERN(vp)->kf_kt->kt_rw & VWRITE))
		return (EOPNOTSUPP);

	return (0);
}

static int
kernfs_access(ap)
	struct vop_access_args /* {
		struct vnode *a_vp;
		int  a_mode;
		struct ucred *a_cred;
		struct proc *a_p;
	} */ *ap;
{
	struct vnode *vp = ap->a_vp;
	struct ucred *cred = ap->a_cred;
	mode_t mode = ap->a_mode;

	if (mode & VEXEC) {
		if (vp->v_flag & VROOT)
			return (0);
		return (EACCES);
	}

	if (cred->cr_uid == 0) {
		if ((vp->v_flag & VROOT) == 0) {
			struct kern_target *kt = VTOKERN(vp)->kf_kt;

			if ((mode & VWRITE) && !(kt->kt_rw & VWRITE))
				return (EROFS);
		}
		return (0);
	}

	if (mode & VWRITE)
		return (EACCES);

	return (0);
}


kernfs_getattr(ap)
	struct vop_getattr_args /* {
		struct vnode *a_vp;
		struct vattr *a_vap;
		struct ucred *a_cred;
		struct proc *a_p;
	} */ *ap;
{
	struct vnode *vp = ap->a_vp;
	struct vattr *vap = ap->a_vap;
	int error = 0;
	char strbuf[KSTRING];

	bzero((caddr_t) vap, sizeof(*vap));
	vattr_null(vap);
	vap->va_uid = 0;
	vap->va_gid = 0;
	vap->va_fsid = vp->v_mount->mnt_stat.f_fsid.val[0];
	/* vap->va_qsize = 0; */
	vap->va_blocksize = DEV_BSIZE;
	microtime(&vap->va_atime);
	vap->va_mtime = vap->va_atime;
	vap->va_ctime = vap->va_ctime;
	vap->va_gen = 0;
	vap->va_flags = 0;
	vap->va_rdev = 0;