NetBSD/sys/miscfs/kernfs/kernfs_vnops.c

738 lines
16 KiB
C

/*
* Copyright (c) 1992 The Regents of the University of California
* Copyright (c) 1990, 1992 Jan-Simon Pendry
* 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.
*
* From:
* Id: kernfs_vnops.c,v 4.1 1994/01/02 14:41:30 jsp Exp
*
* $Id: kernfs_vnops.c,v 1.17 1994/01/05 11:05:12 cgd Exp $
*/
/*
* Kernel parameter filesystem
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/proc.h>
#include <sys/file.h>
#include <sys/vnode.h>
#include <sys/stat.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/buf.h>
#include <miscfs/kernfs/kernfs.h>
#include <ufs/dir.h> /* For readdir() XXX */
#define KSTRING 256 /* Largest I/O available via this filesystem */
#define UIO_MX 32
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;
#define KTM_RO 0
#define KTM_RO_MODE \
((VREAD) | (VREAD >> 3) | (VREAD >> 6))
#define KTM_RW 43
#define KTM_RW_MODE \
((VWRITE) | KTM_RO_MODE)
#define KTM_DIR_MODE \
((VREAD|VEXEC) | ((VREAD|VEXEC) >> 3) | ((VREAD|VEXEC) >> 6))
int kt_rw;
enum vtype 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, KTM_RO, VDIR },
{ "copyright", copyright, KTT_STRING, KTM_RO, VREG },
{ "hostname", 0, KTT_HOSTNAME, KTM_RW, VREG },
{ "hz", &hz, KTT_INT, KTM_RO, VREG },
{ "loadavg", 0, KTT_AVENRUN, KTM_RO, VREG },
{ "physmem", &physmem, KTT_INT, KTM_RO, VREG },
#if 0
{ "root", 0, KTT_NULL, KTM_RO, VDIR },
#endif
{ "rootdev", 0, KTT_NULL, KTM_RO, VBLK },
#ifdef notdef
{ "rrootdev", 0, KTT_NULL, KTM_RO, VCHR },
#endif
{ "time", 0, KTT_TIME, KTM_RO, VREG },
{ "version", version, KTT_STRING, KTM_RO, 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;
{
int xlen;
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, "%d %d %d %d\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);
}
}
/*
* implement access checking.
*
* something very similar to this code is duplicated
* throughout the 4bsd kernel and should be moved
* into kern/vfs_subr.c sometime.
*
* actually, the check for super-user is slightly
* broken since it will allow read access to write-only
* objects. this doesn't cause any particular trouble
* but does mean that the i/o entry points need to check
* that the operation really does make sense.
*/
kernfs_access(vp, mode, cred, p)
struct vnode *vp;
int mode;
struct ucred *cred;
struct proc *p;
{
struct vattr *vap;
struct vattr vattr;
int error;
/*
* If you're the super-user,
* you always get access.
*/
if (cred->cr_uid == (uid_t) 0)
return (0);
vap = &vattr;
if (error = VOP_GETATTR(vp, vap, cred, p))
return (error);
/*
* Access check is based on only one of owner, group, public.
* If not owner, then check group. If not a member of the
* group, then check public access.
*/
if (cred->cr_uid != vap->va_uid) {
gid_t *gp;
int i;
mode >>= 3;
gp = cred->cr_groups;
for (i = 0; i < cred->cr_ngroups; i++, gp++)
if (vap->va_gid == *gp)
goto found;
mode >>= 3;
found:
;
}
if ((vap->va_mode & mode) == mode)
return (0);
return (EACCES);
}
/*
* vp is the current namei directory
* ndp is the name to locate in that directory...
*/
kernfs_lookup(dvp, ndp, p)
struct vnode *dvp;
struct nameidata *ndp;
struct proc *p;
{
char *pname = ndp->ni_ptr;
int error = ENOENT;
int i;
struct vnode *fvp;
#ifdef KERNFS_DIAGNOSTIC
printf("kernfs_lookup(%s)\n", pname);
#endif
if (ndp->ni_namelen == 1 && *pname == '.') {
ndp->ni_dvp = dvp;
ndp->ni_vp = dvp;
VREF(dvp);
/*VOP_LOCK(dvp);*/
return (0);
}
#if 0
if (ndp->ni_namelen == 4 && bcmp(pname, "root", 4) == 0) {
ndp->ni_dvp = rootdir;
ndp->ni_vp = rootdir;
VREF(rootdir);
VREF(rootdir);
VOP_LOCK(rootdir);
return (0);
}
#endif
/*
* /kern/rootdev is the root device
*/
if (ndp->ni_namelen == 7 && bcmp(pname, "rootdev", 7) == 0) {
if (vfinddev(rootdev, VBLK, &fvp))
return (ENXIO);
ndp->ni_dvp = dvp;
ndp->ni_vp = fvp;
VREF(fvp);
VOP_LOCK(fvp);
return (0);
}
for (i = 0; i < nkern_targets; i++) {
struct kern_target *kt = &kern_targets[i];
if (ndp->ni_namelen == strlen(kt->kt_name) &&
bcmp(kt->kt_name, pname, ndp->ni_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_vnodeops, &fvp);
if (error)
goto bad;
VTOKERN(fvp)->kf_kt = &kern_targets[i];
fvp->v_type = VTOKERN(fvp)->kf_kt->kt_vtype;
ndp->ni_dvp = dvp;
ndp->ni_vp = fvp;
#ifdef KERNFS_DIAGNOSTIC
printf("kernfs_lookup: newvp = %x\n", fvp);
#endif
return (0);
bad:;
ndp->ni_dvp = dvp;
ndp->ni_vp = NULL;
#ifdef KERNFS_DIAGNOSTIC
printf("kernfs_lookup: error = %d\n", error);
#endif
return (error);
}
kernfs_open(vp, mode, cred, p)
struct vnode *vp;
int mode;
struct ucred *cred;
struct proc *p;
{
int error;
struct filedesc *fdp;
struct file *fp;
int dfd;
int fd;
#ifdef KERNFS_DIAGNOSTIC
printf("kernfs_open\n");
#endif
/*
* 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",
mode, VTOKERN(vp)->kf_kt->kt_name);
#endif
if ((mode & FWRITE) && VTOKERN(vp)->kf_kt->kt_rw != KTM_RW)
return (EACCES);
return (0);
}
kernfs_getattr(vp, vap, cred, p)
struct vnode *vp;
struct vattr *vap;
struct ucred *cred;
struct proc *p;
{
int error = 0;
char strbuf[KSTRING];
struct kern_target *kt = VTOKERN(vp)->kf_kt;
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;
/* vap->va_qbytes = 0; */
vap->va_bytes = 0;
if (vp->v_flag & VROOT) {
#ifdef KERNFS_DIAGNOSTIC
printf("kernfs_getattr: stat rootdir\n");
#endif
vap->va_type = VDIR;
vap->va_mode = KTM_DIR_MODE;
vap->va_nlink = 2;
vap->va_fileid = 2;
vap->va_size = DEV_BSIZE;
} else {
#ifdef KERNFS_DIAGNOSTIC
printf("kernfs_getattr: stat target %s\n", kt->kt_name);
#endif
vap->va_type = kt->kt_vtype;
vap->va_mode = (kt->kt_rw ? KTM_RW_MODE : KTM_RO_MODE);
vap->va_nlink = 1;
vap->va_fileid = 3 + (kt - kern_targets) / sizeof(*kt);
error = kernfs_xread(kt, strbuf, sizeof(strbuf), &vap->va_size);
}
vp->v_type = vap->va_type;
#ifdef KERNFS_DIAGNOSTIC
printf("kernfs_getattr: return error %d\n", error);
#endif
return (error);
}
kernfs_setattr(vp, vap, cred, p)
struct vnode *vp;
struct vattr *vap;
struct ucred *cred;
struct proc *p;
{
/*
* Silently ignore attribute changes.
* This allows for open with truncate to have no
* effect until some data is written. I want to
* do it this way because all writes are atomic.
*/
return (0);
}
static int
kernfs_read(vp, uio, ioflag, cred)
struct vnode *vp;
struct uio *uio;
int ioflag;
struct ucred *cred;
{
struct kern_target *kt = VTOKERN(vp)->kf_kt;
char strbuf[KSTRING];
int off = uio->uio_offset;
int len = 0;
char *cp = strbuf;
int error;
#ifdef KERNFS_DIAGNOSTIC
printf("kern_read %s\n", kt->kt_name);
#endif
error = kernfs_xread(kt, strbuf, sizeof(strbuf), &len);
if (error)
return (error);
cp = strbuf + off;
len -= off;
return (uiomove(cp, len, uio));
}
static int
kernfs_write(vp, uio, ioflag, cred)
struct vnode *vp;
struct uio *uio;
int ioflag;
struct ucred *cred;
{
struct kern_target *kt = VTOKERN(vp)->kf_kt;
char strbuf[KSTRING];
int len = uio->uio_resid;
char *cp = strbuf;
int xlen;
int error;
if (uio->uio_offset != 0)
return (EINVAL);
xlen = min(uio->uio_resid, KSTRING-1);
error = uiomove(strbuf, xlen, uio);
if (error)
return (error);
if (uio->uio_resid != 0)
return (EIO);
strbuf[xlen] = '\0';
xlen = strlen(strbuf);
return (kernfs_xwrite(kt, strbuf, xlen));
}
kernfs_readdir(vp, uio, cred, eofflagp)
struct vnode *vp;
struct uio *uio;
struct ucred *cred;
int *eofflagp;
{
struct filedesc *fdp;
int i;
int error;
i = uio->uio_offset / UIO_MX;
error = 0;
while (uio->uio_resid > 0) {
#ifdef KERNFS_DIAGNOSTIC
printf("kernfs_readdir: i = %d\n", i);
#endif
if (i >= nkern_targets) {
*eofflagp = 1;
break;
}
{
struct direct d;
struct direct *dp = &d;
struct kern_target *kt = &kern_targets[i];
bzero((caddr_t) dp, UIO_MX);
dp->d_namlen = strlen(kt->kt_name);
bcopy(kt->kt_name, dp->d_name, dp->d_namlen+1);
#ifdef KERNFS_DIAGNOSTIC
printf("kernfs_readdir: name = %s, len = %d\n",
dp->d_name, dp->d_namlen);
#endif
/*
* Fill in the remaining fields
*/
dp->d_reclen = UIO_MX;
dp->d_ino = i + 3;
/*
* And ship to userland
*/
error = uiomove((caddr_t) dp, UIO_MX, uio);
if (error)
break;
}
i++;
}
uio->uio_offset = i * UIO_MX;
return (error);
}
kernfs_inactive(vp, p)
struct vnode *vp;
struct proc *p;
{
/*
* Clear out the v_type field to avoid
* nasty things happening in vgone().
*/
vp->v_type = VNON;
#ifdef KERNFS_DIAGNOSTIC
printf("kernfs_inactive(%x)\n", vp);
#endif
return (0);
}
/*
* Print out the contents of a kernfs vnode.
*/
/* ARGSUSED */
kernfs_print(vp)
struct vnode *vp;
{
printf("tag VT_NON, kernfs vnode\n");
}
/*
* kernfs vnode unsupported operation
*/
kernfs_enotsupp()
{
return (EOPNOTSUPP);
}
/*
* kernfs "should never get here" operation
*/
kernfs_badop()
{
panic("kernfs: bad op");
/* NOTREACHED */
}
/*
* kernfs vnode null operation
*/
kernfs_nullop()
{
return (0);
}
#define kernfs_create ((int (*) __P(( \
struct nameidata *ndp, \
struct vattr *vap, \
struct proc *p))) kernfs_enotsupp)
#define kernfs_mknod ((int (*) __P(( \
struct nameidata *ndp, \
struct vattr *vap, \
struct ucred *cred, \
struct proc *p))) kernfs_enotsupp)
#define kernfs_close ((int (*) __P(( \
struct vnode *vp, \
int fflag, \
struct ucred *cred, \
struct proc *p))) nullop)
#define kernfs_ioctl ((int (*) __P(( \
struct vnode *vp, \
int command, \
caddr_t data, \
int fflag, \
struct ucred *cred, \
struct proc *p))) kernfs_enotsupp)
#define kernfs_select ((int (*) __P(( \
struct vnode *vp, \
int which, \
int fflags, \
struct ucred *cred, \
struct proc *p))) kernfs_enotsupp)
#define kernfs_mmap ((int (*) __P(( \
struct vnode *vp, \
int fflags, \
struct ucred *cred, \
struct proc *p))) kernfs_enotsupp)
#define kernfs_fsync ((int (*) __P(( \
struct vnode *vp, \
int fflags, \
struct ucred *cred, \
int waitfor, \
struct proc *p))) nullop)
#define kernfs_seek ((int (*) __P(( \
struct vnode *vp, \
off_t oldoff, \
off_t newoff, \
struct ucred *cred))) nullop)
#define kernfs_remove ((int (*) __P(( \
struct nameidata *ndp, \
struct proc *p))) kernfs_enotsupp)
#define kernfs_link ((int (*) __P(( \
struct vnode *vp, \
struct nameidata *ndp, \
struct proc *p))) kernfs_enotsupp)
#define kernfs_rename ((int (*) __P(( \
struct nameidata *fndp, \
struct nameidata *tdnp, \
struct proc *p))) kernfs_enotsupp)
#define kernfs_mkdir ((int (*) __P(( \
struct nameidata *ndp, \
struct vattr *vap, \
struct proc *p))) kernfs_enotsupp)
#define kernfs_rmdir ((int (*) __P(( \
struct nameidata *ndp, \
struct proc *p))) kernfs_enotsupp)
#define kernfs_symlink ((int (*) __P(( \
struct nameidata *ndp, \
struct vattr *vap, \
char *target, \
struct proc *p))) kernfs_enotsupp)
#define kernfs_readlink ((int (*) __P(( \
struct vnode *vp, \
struct uio *uio, \
struct ucred *cred))) kernfs_enotsupp)
#define kernfs_abortop ((int (*) __P(( \
struct nameidata *ndp))) nullop)
#ifdef KERNFS_DIAGNOSTIC
int kernfs_reclaim(vp)
struct vnode *vp;
{
printf("kernfs_reclaim(%x)\n", vp);
return (0);
}
#else
#define kernfs_reclaim ((int (*) __P(( \
struct vnode *vp))) nullop)
#endif
#define kernfs_lock ((int (*) __P(( \
struct vnode *vp))) nullop)
#define kernfs_unlock ((int (*) __P(( \
struct vnode *vp))) nullop)
#define kernfs_bmap ((int (*) __P(( \
struct vnode *vp, \
daddr_t bn, \
struct vnode **vpp, \
daddr_t *bnp))) kernfs_badop)
#define kernfs_strategy ((int (*) __P(( \
struct buf *bp))) kernfs_badop)
#define kernfs_islocked ((int (*) __P(( \
struct vnode *vp))) nullop)
#define kernfs_advlock ((int (*) __P(( \
struct vnode *vp, \
caddr_t id, \
int op, \
struct flock *fl, \
int flags))) kernfs_enotsupp)
struct vnodeops kernfs_vnodeops = {
kernfs_lookup, /* lookup */
kernfs_create, /* create */
kernfs_mknod, /* mknod */
kernfs_open, /* open */
kernfs_close, /* close */
kernfs_access, /* access */
kernfs_getattr, /* getattr */
kernfs_setattr, /* setattr */
kernfs_read, /* read */
kernfs_write, /* write */
kernfs_ioctl, /* ioctl */
kernfs_select, /* select */
kernfs_mmap, /* mmap */
kernfs_fsync, /* fsync */
kernfs_seek, /* seek */
kernfs_remove, /* remove */
kernfs_link, /* link */
kernfs_rename, /* rename */
kernfs_mkdir, /* mkdir */
kernfs_rmdir, /* rmdir */
kernfs_symlink, /* symlink */
kernfs_readdir, /* readdir */
kernfs_readlink, /* readlink */
kernfs_abortop, /* abortop */
kernfs_inactive, /* inactive */
kernfs_reclaim, /* reclaim */
kernfs_lock, /* lock */
kernfs_unlock, /* unlock */
kernfs_bmap, /* bmap */
kernfs_strategy, /* strategy */
kernfs_print, /* print */
kernfs_islocked, /* islocked */
kernfs_advlock, /* advlock */
};