freebsd-dev/sys/miscfs/kernfs/kernfs_vnops.c
1999-01-27 22:42:27 +00:00

664 lines
16 KiB
C

/*
* 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 8.15 (Berkeley) 5/21/95
* $Id: kernfs_vnops.c,v 1.37 1998/12/07 21:58:31 archie Exp $
*/
/*
* Kernel parameter filesystem (/kern)
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/vmmeter.h>
#include <sys/time.h>
#include <sys/vnode.h>
#include <sys/malloc.h>
#include <sys/stat.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/dirent.h>
#include <sys/resource.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)
static struct kern_target {
u_char kt_type;
u_char kt_namlen;
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_BOOTFILE 49
#define KTT_AVENRUN 53
#define KTT_DEVICE 71
u_char kt_tag;
u_char kt_vtype;
mode_t kt_mode;
} kern_targets[] = {
/* NOTE: The name must be less than UIO_MX-16 chars in length */
#define N(s) sizeof(s)-1, s
/* name data tag type ro/rw */
{ DT_DIR, N("."), 0, KTT_NULL, VDIR, DIR_MODE },
{ DT_DIR, N(".."), 0, KTT_NULL, VDIR, DIR_MODE },
{ DT_REG, N("boottime"), &boottime.tv_sec, KTT_INT, VREG, READ_MODE },
{ DT_REG, N("copyright"), copyright, KTT_STRING, VREG, READ_MODE },
{ DT_REG, N("hostname"), 0, KTT_HOSTNAME, VREG, WRITE_MODE },
{ DT_REG, N("bootfile"), 0, KTT_BOOTFILE, VREG, READ_MODE },
{ DT_REG, N("hz"), &hz, KTT_INT, VREG, READ_MODE },
{ DT_REG, N("loadavg"), 0, KTT_AVENRUN, VREG, READ_MODE },
{ DT_REG, N("pagesize"), &cnt.v_page_size, KTT_INT, VREG, READ_MODE },
{ DT_REG, N("physmem"), &physmem, KTT_INT, VREG, READ_MODE },
#if 0
{ DT_DIR, N("root"), 0, KTT_NULL, VDIR, DIR_MODE },
{ DT_BLK, N("rootdev"), &rootdev, KTT_DEVICE, VBLK, READ_MODE },
{ DT_CHR, N("rrootdev"), &rrootdev, KTT_DEVICE, VCHR, READ_MODE },
#endif
{ DT_REG, N("time"), 0, KTT_TIME, VREG, READ_MODE },
{ DT_REG, N("version"), version, KTT_STRING, VREG, READ_MODE },
#undef N
};
static int nkern_targets = sizeof(kern_targets) / sizeof(kern_targets[0]);
static int kernfs_access __P((struct vop_access_args *ap));
static int kernfs_badop __P((void));
static int kernfs_getattr __P((struct vop_getattr_args *ap));
static int kernfs_inactive __P((struct vop_inactive_args *ap));
static int kernfs_lookup __P((struct vop_lookup_args *ap));
static int kernfs_print __P((struct vop_print_args *ap));
static int kernfs_read __P((struct vop_read_args *ap));
static int kernfs_readdir __P((struct vop_readdir_args *ap));
static int kernfs_reclaim __P((struct vop_reclaim_args *ap));
static int kernfs_setattr __P((struct vop_setattr_args *ap));
static int kernfs_write __P((struct vop_write_args *ap));
static int kernfs_xread __P((struct kern_target *kt, char *buf, int len,
int *lenp));
static int kernfs_xwrite __P((struct kern_target *kt, char *buf, int len));
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);
snprintf(buf, len, "%ld %ld\n", tv.tv_sec, tv.tv_usec);
break;
}
case KTT_INT: {
int *ip = kt->kt_data;
snprintf(buf, len, "%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 = strlen(hostname);
if (xlen >= (len-2))
return (EINVAL);
bcopy(cp, buf, xlen);
buf[xlen] = '\n';
buf[xlen+1] = '\0';
break;
}
case KTT_BOOTFILE: {
char *cp = kernelname;
int xlen = strlen(cp) + 1;
if (xlen >= (len-2))
return (EINVAL);
bcopy(cp, buf, xlen);
buf[xlen] = '\n';
buf[xlen+1] = '\0';
break;
}
case KTT_AVENRUN:
snprintf(buf, len, "%lu %lu %lu %ld\n",
(u_long)averunnable.ldavg[0], (u_long)averunnable.ldavg[1],
(u_long)averunnable.ldavg[2], averunnable.fscale);
break;
default:
return (EIO);
}
*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:
/* XXX BOGUS !!! no check for the length */
if (buf[len-1] == '\n')
--len;
bcopy(buf, hostname, len);
hostname[len] = '\0';
return (0);
default:
return (EIO);
}
}
/*
* vp is the current namei directory
* ndp is the name to locate in that directory...
*/
static int
kernfs_lookup(ap)
struct vop_lookup_args /* {
struct vnode * a_dvp;
struct vnode ** a_vpp;
struct componentname * a_cnp;
} */ *ap;
{
struct componentname *cnp = ap->a_cnp;
struct vnode **vpp = ap->a_vpp;
struct vnode *dvp = ap->a_dvp;
char *pname = cnp->cn_nameptr;
struct proc *p = cnp->cn_proc;
struct kern_target *kt;
struct vnode *fvp;
int error, i;
#ifdef KERNFS_DIAGNOSTIC
printf("kernfs_lookup(%x)\n", ap);
printf("kernfs_lookup(dp = %x, vpp = %x, cnp = %x)\n", dvp, vpp, ap->a_cnp);
printf("kernfs_lookup(%s)\n", pname);
#endif
*vpp = NULLVP;
if (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)
return (EROFS);
VOP_UNLOCK(dvp, 0, p);
if (cnp->cn_namelen == 1 && *pname == '.') {
*vpp = dvp;
VREF(dvp);
vn_lock(dvp, LK_SHARED | LK_RETRY, p);
return (0);
}
#if 0
if (cnp->cn_namelen == 4 && bcmp(pname, "root", 4) == 0) {
*vpp = rootdir;
VREF(rootdir);
vn_lock(rootdir, LK_SHARED | LK_RETRY, p)
return (0);
}
#endif
for (kt = kern_targets, i = 0; i < nkern_targets; kt++, i++) {
if (cnp->cn_namelen == kt->kt_namlen &&
bcmp(kt->kt_name, pname, cnp->cn_namelen) == 0)
goto found;
}
#ifdef KERNFS_DIAGNOSTIC
printf("kernfs_lookup: i = %d, failed", i);
#endif
vn_lock(dvp, LK_SHARED | LK_RETRY, p);
return (cnp->cn_nameiop == LOOKUP ? ENOENT : EROFS);
found:
if (kt->kt_tag == KTT_DEVICE) {
dev_t *dp = kt->kt_data;
loop:
if (*dp == NODEV || !vfinddev(*dp, kt->kt_vtype, &fvp)) {
vn_lock(dvp, LK_SHARED | LK_RETRY, p);
return (ENOENT);
}
*vpp = fvp;
if (vget(fvp, LK_EXCLUSIVE, p))
goto loop;
return (0);
}
#ifdef KERNFS_DIAGNOSTIC
printf("kernfs_lookup: allocate new vnode\n");
#endif
if ((error = getnewvnode(VT_KERNFS, dvp->v_mount, kernfs_vnodeop_p,
&fvp)) != 0) {
vn_lock(dvp, LK_SHARED | LK_RETRY, p);
return (error);
}
MALLOC(fvp->v_data, void *, sizeof(struct kernfs_node), M_TEMP,
M_WAITOK);
VTOKERN(fvp)->kf_kt = kt;
fvp->v_type = kt->kt_vtype;
vn_lock(fvp, LK_SHARED | LK_RETRY, p);
*vpp = fvp;
#ifdef KERNFS_DIAGNOSTIC
printf("kernfs_lookup: newvp = %x\n", fvp);
#endif
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;
{
register struct vnode *vp = ap->a_vp;
register struct ucred *cred = ap->a_cred;
mode_t amode = ap->a_mode;
mode_t fmode =
(vp->v_flag & VROOT) ? DIR_MODE : VTOKERN(vp)->kf_kt->kt_mode;
mode_t mask = 0;
register gid_t *gp;
int i;
/* Some files are simply not modifiable. */
if ((amode & VWRITE) && (fmode & (S_IWUSR|S_IWGRP|S_IWOTH)) == 0)
return (EPERM);
/* Root can do anything else. */
if (cred->cr_uid == 0)
return (0);
/* Check for group 0 (wheel) permissions. */
for (i = 0, gp = cred->cr_groups; i < cred->cr_ngroups; i++, gp++)
if (*gp == 0) {
if (amode & VEXEC)
mask |= S_IXGRP;
if (amode & VREAD)
mask |= S_IRGRP;
if (amode & VWRITE)
mask |= S_IWGRP;
return ((fmode & mask) == mask ? 0 : EACCES);
}
/* Otherwise, check everyone else. */
if (amode & VEXEC)
mask |= S_IXOTH;
if (amode & VREAD)
mask |= S_IROTH;
if (amode & VWRITE)
mask |= S_IWOTH;
return ((fmode & mask) == mask ? 0 : EACCES);
}
static int
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_size = 0;
vap->va_blocksize = DEV_BSIZE;
nanotime(&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_bytes = 0;
if (vp->v_flag & VROOT) {
#ifdef KERNFS_DIAGNOSTIC
printf("kernfs_getattr: stat rootdir\n");
#endif
vap->va_type = VDIR;
vap->va_mode = DIR_MODE;
vap->va_nlink = 2;
vap->va_fileid = 2;
vap->va_size = DEV_BSIZE;
} else {
struct kern_target *kt = VTOKERN(vp)->kf_kt;
int nbytes;
#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_mode;
vap->va_nlink = 1;
vap->va_fileid = 1 + (kt - kern_targets) / sizeof(*kt);
error = kernfs_xread(kt, strbuf, sizeof(strbuf), &nbytes);
vap->va_size = nbytes;
}
#ifdef KERNFS_DIAGNOSTIC
printf("kernfs_getattr: return error %d\n", error);
#endif
return (error);
}
static int
kernfs_setattr(ap)
struct vop_setattr_args /* {
struct vnode *a_vp;
struct vattr *a_vap;
struct ucred *a_cred;
struct proc *a_p;
} */ *ap;
{
if (ap->a_vap->va_flags != VNOVAL)
return (EOPNOTSUPP);
/*
* 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(ap)
struct vop_read_args /* {
struct vnode *a_vp;
struct uio *a_uio;
int a_ioflag;
struct ucred *a_cred;
} */ *ap;
{
struct vnode *vp = ap->a_vp;
struct uio *uio = ap->a_uio;
struct kern_target *kt;
char strbuf[KSTRING];
int off = uio->uio_offset;
int error, len;
if (vp->v_type == VDIR)
return (EOPNOTSUPP);
kt = VTOKERN(vp)->kf_kt;
#ifdef KERNFS_DIAGNOSTIC
printf("kern_read %s\n", kt->kt_name);
#endif
len = 0;
if ((error = kernfs_xread(kt, strbuf, sizeof(strbuf), &len)) != 0)
return (error);
if (len <= off)
return (0);
return (uiomove(&strbuf[off], len - off, uio));
}
static int
kernfs_write(ap)
struct vop_write_args /* {
struct vnode *a_vp;
struct uio *a_uio;
int a_ioflag;
struct ucred *a_cred;
} */ *ap;
{
struct vnode *vp = ap->a_vp;
struct uio *uio = ap->a_uio;
struct kern_target *kt;
int error, xlen;
char strbuf[KSTRING];
if (vp->v_type == VDIR)
return (EOPNOTSUPP);
kt = VTOKERN(vp)->kf_kt;
if (uio->uio_offset != 0)
return (EINVAL);
xlen = min(uio->uio_resid, KSTRING-1);
if ((error = uiomove(strbuf, xlen, uio)) != 0)
return (error);
if (uio->uio_resid != 0)
return (EIO);
strbuf[xlen] = '\0';
xlen = strlen(strbuf);
return (kernfs_xwrite(kt, strbuf, xlen));
}
static int
kernfs_readdir(ap)
struct vop_readdir_args /* {
struct vnode *a_vp;
struct uio *a_uio;
struct ucred *a_cred;
int *a_eofflag;
int *a_ncookies;
u_long **a_cookies;
} */ *ap;
{
int error, i, off;
struct uio *uio = ap->a_uio;
struct kern_target *kt;
struct dirent d;
if (ap->a_vp->v_type != VDIR)
return (ENOTDIR);
off = (int)uio->uio_offset;
if (off != uio->uio_offset || off < 0 || (u_int)off % UIO_MX != 0 ||
uio->uio_resid < UIO_MX)
return (EINVAL);
i = (u_int)off / UIO_MX;
error = 0;
for (kt = &kern_targets[i];
uio->uio_resid >= UIO_MX && i < nkern_targets; kt++, i++) {
struct dirent *dp = &d;
#ifdef KERNFS_DIAGNOSTIC
printf("kernfs_readdir: i = %d\n", i);
#endif
if (kt->kt_tag == KTT_DEVICE) {
dev_t *dp = kt->kt_data;
struct vnode *fvp;
if (*dp == NODEV || !vfinddev(*dp, kt->kt_vtype, &fvp))
continue;
}
bzero((caddr_t)dp, UIO_MX);
dp->d_namlen = kt->kt_namlen;
bcopy(kt->kt_name, dp->d_name, kt->kt_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_fileno = i + 3;
dp->d_type = kt->kt_type;
/*
* And ship to userland
*/
if ((error = uiomove((caddr_t)dp, UIO_MX, uio)) != 0)
break;
}
uio->uio_offset = i * UIO_MX;
return (error);
}
static int
kernfs_inactive(ap)
struct vop_inactive_args /* {
struct vnode *a_vp;
struct proc *a_p;
} */ *ap;
{
struct vnode *vp = ap->a_vp;
#ifdef KERNFS_DIAGNOSTIC
printf("kernfs_inactive(%x)\n", vp);
#endif
/*
* Clear out the v_type field to avoid
* nasty things happening in vgone().
*/
VOP_UNLOCK(vp, 0, ap->a_p);
vp->v_type = VNON;
return (0);
}
static int
kernfs_reclaim(ap)
struct vop_reclaim_args /* {
struct vnode *a_vp;
} */ *ap;
{
struct vnode *vp = ap->a_vp;
#ifdef KERNFS_DIAGNOSTIC
printf("kernfs_reclaim(%x)\n", vp);
#endif
if (vp->v_data) {
FREE(vp->v_data, M_TEMP);
vp->v_data = 0;
}
return (0);
}
/*
* Print out the contents of a kernfs vnode.
*/
/* ARGSUSED */
static int
kernfs_print(ap)
struct vop_print_args /* {
struct vnode *a_vp;
} */ *ap;
{
printf("tag VT_KERNFS, kernfs vnode\n");
return (0);
}
/*
* Kernfs "should never get here" operation
*/
static int
kernfs_badop()
{
return (EIO);
}
vop_t **kernfs_vnodeop_p;
static struct vnodeopv_entry_desc kernfs_vnodeop_entries[] = {
{ &vop_default_desc, (vop_t *) vop_defaultop },
{ &vop_access_desc, (vop_t *) kernfs_access },
{ &vop_bmap_desc, (vop_t *) kernfs_badop },
{ &vop_getattr_desc, (vop_t *) kernfs_getattr },
{ &vop_inactive_desc, (vop_t *) kernfs_inactive },
{ &vop_lookup_desc, (vop_t *) kernfs_lookup },
{ &vop_pathconf_desc, (vop_t *) vop_stdpathconf },
{ &vop_print_desc, (vop_t *) kernfs_print },
{ &vop_read_desc, (vop_t *) kernfs_read },
{ &vop_readdir_desc, (vop_t *) kernfs_readdir },
{ &vop_reclaim_desc, (vop_t *) kernfs_reclaim },
{ &vop_setattr_desc, (vop_t *) kernfs_setattr },
{ &vop_write_desc, (vop_t *) kernfs_write },
{ NULL, NULL }
};
static struct vnodeopv_desc kernfs_vnodeop_opv_desc =
{ &kernfs_vnodeop_p, kernfs_vnodeop_entries };
VNODEOP_SET(kernfs_vnodeop_opv_desc);