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freebsd/sys/fs/fdescfs/fdesc_vnops.c
Robert Watson 4a14441044 Update kernel inclusions of capability.h to use capsicum.h instead; some
further refinement is required as some device drivers intended to be
portable over FreeBSD versions rely on __FreeBSD_version to decide whether
to include capability.h.

MFC after:	3 weeks
2014-03-16 10:55:57 +00:00

583 lines
13 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.
* 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.
*
* @(#)fdesc_vnops.c 8.9 (Berkeley) 1/21/94
*
* $FreeBSD$
*/
/*
* /dev/fd Filesystem
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/capsicum.h>
#include <sys/conf.h>
#include <sys/dirent.h>
#include <sys/filedesc.h>
#include <sys/kernel.h> /* boottime */
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/malloc.h>
#include <sys/file.h> /* Must come after sys/malloc.h */
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/proc.h>
#include <sys/stat.h>
#include <sys/vnode.h>
#include <fs/fdescfs/fdesc.h>
#define NFDCACHE 4
#define FD_NHASH(ix) \
(&fdhashtbl[(ix) & fdhash])
static LIST_HEAD(fdhashhead, fdescnode) *fdhashtbl;
static u_long fdhash;
struct mtx fdesc_hashmtx;
static vop_getattr_t fdesc_getattr;
static vop_lookup_t fdesc_lookup;
static vop_open_t fdesc_open;
static vop_readdir_t fdesc_readdir;
static vop_reclaim_t fdesc_reclaim;
static vop_setattr_t fdesc_setattr;
static struct vop_vector fdesc_vnodeops = {
.vop_default = &default_vnodeops,
.vop_access = VOP_NULL,
.vop_getattr = fdesc_getattr,
.vop_lookup = fdesc_lookup,
.vop_open = fdesc_open,
.vop_pathconf = vop_stdpathconf,
.vop_readdir = fdesc_readdir,
.vop_reclaim = fdesc_reclaim,
.vop_setattr = fdesc_setattr,
};
static void fdesc_insmntque_dtr(struct vnode *, void *);
static void fdesc_remove_entry(struct fdescnode *);
/*
* Initialise cache headers
*/
int
fdesc_init(vfsp)
struct vfsconf *vfsp;
{
mtx_init(&fdesc_hashmtx, "fdescfs_hash", NULL, MTX_DEF);
fdhashtbl = hashinit(NFDCACHE, M_CACHE, &fdhash);
return (0);
}
/*
* Uninit ready for unload.
*/
int
fdesc_uninit(vfsp)
struct vfsconf *vfsp;
{
hashdestroy(fdhashtbl, M_CACHE, fdhash);
mtx_destroy(&fdesc_hashmtx);
return (0);
}
/*
* If allocating vnode fails, call this.
*/
static void
fdesc_insmntque_dtr(struct vnode *vp, void *arg)
{
vgone(vp);
vput(vp);
}
/*
* Remove an entry from the hash if it exists.
*/
static void
fdesc_remove_entry(struct fdescnode *fd)
{
struct fdhashhead *fc;
struct fdescnode *fd2;
fc = FD_NHASH(fd->fd_ix);
mtx_lock(&fdesc_hashmtx);
LIST_FOREACH(fd2, fc, fd_hash) {
if (fd == fd2) {
LIST_REMOVE(fd, fd_hash);
break;
}
}
mtx_unlock(&fdesc_hashmtx);
}
int
fdesc_allocvp(ftype, fd_fd, ix, mp, vpp)
fdntype ftype;
unsigned fd_fd;
int ix;
struct mount *mp;
struct vnode **vpp;
{
struct fdescmount *fmp;
struct fdhashhead *fc;
struct fdescnode *fd, *fd2;
struct vnode *vp, *vp2;
struct thread *td;
int error = 0;
td = curthread;
fc = FD_NHASH(ix);
loop:
mtx_lock(&fdesc_hashmtx);
/*
* If a forced unmount is progressing, we need to drop it. The flags are
* protected by the hashmtx.
*/
fmp = (struct fdescmount *)mp->mnt_data;
if (fmp == NULL || fmp->flags & FMNT_UNMOUNTF) {
mtx_unlock(&fdesc_hashmtx);
return (-1);
}
LIST_FOREACH(fd, fc, fd_hash) {
if (fd->fd_ix == ix && fd->fd_vnode->v_mount == mp) {
/* Get reference to vnode in case it's being free'd */
vp = fd->fd_vnode;
VI_LOCK(vp);
mtx_unlock(&fdesc_hashmtx);
if (vget(vp, LK_EXCLUSIVE | LK_INTERLOCK, td))
goto loop;
*vpp = vp;
return (0);
}
}
mtx_unlock(&fdesc_hashmtx);
fd = malloc(sizeof(struct fdescnode), M_TEMP, M_WAITOK);
error = getnewvnode("fdescfs", mp, &fdesc_vnodeops, &vp);
if (error) {
free(fd, M_TEMP);
return (error);
}
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
vp->v_data = fd;
fd->fd_vnode = vp;
fd->fd_type = ftype;
fd->fd_fd = fd_fd;
fd->fd_ix = ix;
error = insmntque1(vp, mp, fdesc_insmntque_dtr, NULL);
if (error != 0) {
*vpp = NULLVP;
return (error);
}
/* Make sure that someone didn't beat us when inserting the vnode. */
mtx_lock(&fdesc_hashmtx);
/*
* If a forced unmount is progressing, we need to drop it. The flags are
* protected by the hashmtx.
*/
fmp = (struct fdescmount *)mp->mnt_data;
if (fmp == NULL || fmp->flags & FMNT_UNMOUNTF) {
mtx_unlock(&fdesc_hashmtx);
vgone(vp);
vput(vp);
*vpp = NULLVP;
return (-1);
}
LIST_FOREACH(fd2, fc, fd_hash) {
if (fd2->fd_ix == ix && fd2->fd_vnode->v_mount == mp) {
/* Get reference to vnode in case it's being free'd */
vp2 = fd2->fd_vnode;
VI_LOCK(vp2);
mtx_unlock(&fdesc_hashmtx);
error = vget(vp2, LK_EXCLUSIVE | LK_INTERLOCK, td);
/* Someone beat us, dec use count and wait for reclaim */
vgone(vp);
vput(vp);
/* If we didn't get it, return no vnode. */
if (error)
vp2 = NULLVP;
*vpp = vp2;
return (error);
}
}
/* If we came here, we can insert it safely. */
LIST_INSERT_HEAD(fc, fd, fd_hash);
mtx_unlock(&fdesc_hashmtx);
*vpp = vp;
return (0);
}
/*
* vp is the current namei directory
* ndp is the name to locate in that directory...
*/
static int
fdesc_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;
char *pname = cnp->cn_nameptr;
struct thread *td = cnp->cn_thread;
struct file *fp;
int nlen = cnp->cn_namelen;
u_int fd, fd1;
int error;
struct vnode *fvp;
if ((cnp->cn_flags & ISLASTCN) &&
(cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) {
error = EROFS;
goto bad;
}
if (cnp->cn_namelen == 1 && *pname == '.') {
*vpp = dvp;
VREF(dvp);
return (0);
}
if (VTOFDESC(dvp)->fd_type != Froot) {
error = ENOTDIR;
goto bad;
}
fd = 0;
/* the only time a leading 0 is acceptable is if it's "0" */
if (*pname == '0' && nlen != 1) {
error = ENOENT;
goto bad;
}
while (nlen--) {
if (*pname < '0' || *pname > '9') {
error = ENOENT;
goto bad;
}
fd1 = 10 * fd + *pname++ - '0';
if (fd1 < fd) {
error = ENOENT;
goto bad;
}
fd = fd1;
}
/*
* No rights to check since 'fp' isn't actually used.
*/
if ((error = fget(td, fd, NULL, &fp)) != 0)
goto bad;
/* Check if we're looking up ourselves. */
if (VTOFDESC(dvp)->fd_ix == FD_DESC + fd) {
/*
* In case we're holding the last reference to the file, the dvp
* will be re-acquired.
*/
vhold(dvp);
VOP_UNLOCK(dvp, 0);
fdrop(fp, td);
/* Re-aquire the lock afterwards. */
vn_lock(dvp, LK_RETRY | LK_EXCLUSIVE);
vdrop(dvp);
fvp = dvp;
} else {
/*
* Unlock our root node (dvp) when doing this, since we might
* deadlock since the vnode might be locked by another thread
* and the root vnode lock will be obtained afterwards (in case
* we're looking up the fd of the root vnode), which will be the
* opposite lock order. Vhold the root vnode first so we don't
* lose it.
*/
vhold(dvp);
VOP_UNLOCK(dvp, 0);
error = fdesc_allocvp(Fdesc, fd, FD_DESC + fd, dvp->v_mount,
&fvp);
fdrop(fp, td);
/*
* The root vnode must be locked last to prevent deadlock condition.
*/
vn_lock(dvp, LK_RETRY | LK_EXCLUSIVE);
vdrop(dvp);
}
if (error)
goto bad;
*vpp = fvp;
return (0);
bad:
*vpp = NULL;
return (error);
}
static int
fdesc_open(ap)
struct vop_open_args /* {
struct vnode *a_vp;
int a_mode;
struct ucred *a_cred;
struct thread *a_td;
} */ *ap;
{
struct vnode *vp = ap->a_vp;
if (VTOFDESC(vp)->fd_type == Froot)
return (0);
/*
* XXX Kludge: set td->td_proc->p_dupfd to contain the value of the file
* descriptor being sought for duplication. The error return ensures
* that the vnode for this device will be released by vn_open. Open
* will detect this special error and take the actions in dupfdopen.
* Other callers of vn_open or VOP_OPEN will simply report the
* error.
*/
ap->a_td->td_dupfd = VTOFDESC(vp)->fd_fd; /* XXX */
return (ENODEV);
}
static int
fdesc_getattr(ap)
struct vop_getattr_args /* {
struct vnode *a_vp;
struct vattr *a_vap;
struct ucred *a_cred;
} */ *ap;
{
struct vnode *vp = ap->a_vp;
struct vattr *vap = ap->a_vap;
vap->va_mode = S_IRUSR|S_IXUSR|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH;
vap->va_fileid = VTOFDESC(vp)->fd_ix;
vap->va_uid = 0;
vap->va_gid = 0;
vap->va_blocksize = DEV_BSIZE;
vap->va_atime.tv_sec = boottime.tv_sec;
vap->va_atime.tv_nsec = 0;
vap->va_mtime = vap->va_atime;
vap->va_ctime = vap->va_mtime;
vap->va_gen = 0;
vap->va_flags = 0;
vap->va_bytes = 0;
vap->va_filerev = 0;
switch (VTOFDESC(vp)->fd_type) {
case Froot:
vap->va_type = VDIR;
vap->va_nlink = 2;
vap->va_size = DEV_BSIZE;
vap->va_rdev = NODEV;
break;
case Fdesc:
vap->va_type = VCHR;
vap->va_nlink = 1;
vap->va_size = 0;
vap->va_rdev = makedev(0, vap->va_fileid);
break;
default:
panic("fdesc_getattr");
break;
}
vp->v_type = vap->va_type;
return (0);
}
static int
fdesc_setattr(ap)
struct vop_setattr_args /* {
struct vnode *a_vp;
struct vattr *a_vap;
struct ucred *a_cred;
} */ *ap;
{
struct vattr *vap = ap->a_vap;
struct vnode *vp;
struct mount *mp;
struct file *fp;
struct thread *td = curthread;
cap_rights_t rights;
unsigned fd;
int error;
/*
* Can't mess with the root vnode
*/
if (VTOFDESC(ap->a_vp)->fd_type == Froot)
return (EACCES);
fd = VTOFDESC(ap->a_vp)->fd_fd;
/*
* Allow setattr where there is an underlying vnode.
*/
error = getvnode(td->td_proc->p_fd, fd,
cap_rights_init(&rights, CAP_EXTATTR_SET), &fp);
if (error) {
/*
* getvnode() returns EINVAL if the file descriptor is not
* backed by a vnode. Silently drop all changes except
* chflags(2) in this case.
*/
if (error == EINVAL) {
if (vap->va_flags != VNOVAL)
error = EOPNOTSUPP;
else
error = 0;
}
return (error);
}
vp = fp->f_vnode;
if ((error = vn_start_write(vp, &mp, V_WAIT | PCATCH)) == 0) {
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
error = VOP_SETATTR(vp, ap->a_vap, ap->a_cred);
VOP_UNLOCK(vp, 0);
vn_finished_write(mp);
}
fdrop(fp, td);
return (error);
}
#define UIO_MX 16
static int
fdesc_readdir(ap)
struct vop_readdir_args /* {
struct vnode *a_vp;
struct uio *a_uio;
struct ucred *a_cred;
int *a_eofflag;
u_long *a_cookies;
int a_ncookies;
} */ *ap;
{
struct uio *uio = ap->a_uio;
struct filedesc *fdp;
struct dirent d;
struct dirent *dp = &d;
int error, i, off, fcnt;
if (VTOFDESC(ap->a_vp)->fd_type != Froot)
panic("fdesc_readdir: not dir");
if (ap->a_ncookies != NULL)
*ap->a_ncookies = 0;
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;
fdp = uio->uio_td->td_proc->p_fd;
error = 0;
fcnt = i - 2; /* The first two nodes are `.' and `..' */
FILEDESC_SLOCK(fdp);
while (i < fdp->fd_nfiles + 2 && uio->uio_resid >= UIO_MX) {
bzero((caddr_t)dp, UIO_MX);
switch (i) {
case 0: /* `.' */
case 1: /* `..' */
dp->d_fileno = i + FD_ROOT;
dp->d_namlen = i + 1;
dp->d_reclen = UIO_MX;
bcopy("..", dp->d_name, dp->d_namlen);
dp->d_name[i + 1] = '\0';
dp->d_type = DT_DIR;
break;
default:
if (fdp->fd_ofiles[fcnt].fde_file == NULL)
break;
dp->d_namlen = sprintf(dp->d_name, "%d", fcnt);
dp->d_reclen = UIO_MX;
dp->d_type = DT_CHR;
dp->d_fileno = i + FD_DESC;
break;
}
if (dp->d_namlen != 0) {
/*
* And ship to userland
*/
FILEDESC_SUNLOCK(fdp);
error = uiomove(dp, UIO_MX, uio);
if (error)
goto done;
FILEDESC_SLOCK(fdp);
}
i++;
fcnt++;
}
FILEDESC_SUNLOCK(fdp);
done:
uio->uio_offset = i * UIO_MX;
return (error);
}
static int
fdesc_reclaim(ap)
struct vop_reclaim_args /* {
struct vnode *a_vp;
} */ *ap;
{
struct vnode *vp;
struct fdescnode *fd;
vp = ap->a_vp;
fd = VTOFDESC(vp);
fdesc_remove_entry(fd);
free(vp->v_data, M_TEMP);
vp->v_data = NULL;
return (0);
}