freebsd-dev/sys/fs/fdescfs/fdesc_vnops.c
Jeff Roberson ad70122060 - Change all LK_SHARE locks to LK_EXCLUSIVE. Shared locks aren't quite safe
yet
 - Use vop_std{lock,unlock,islocked}.
2002-07-09 19:43:39 +00:00

576 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.
* 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.
*
* @(#)fdesc_vnops.c 8.9 (Berkeley) 1/21/94
*
* $FreeBSD$
*/
/*
* /dev/fd Filesystem
*/
#include <sys/param.h>
#include <sys/systm.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 FDL_WANT 0x01
#define FDL_LOCKED 0x02
static int fdcache_lock;
static vop_t **fdesc_vnodeop_p;
#define NFDCACHE 4
#define FD_NHASH(ix) \
(&fdhashtbl[(ix) & fdhash])
static LIST_HEAD(fdhashhead, fdescnode) *fdhashtbl;
static u_long fdhash;
static int fdesc_getattr(struct vop_getattr_args *ap);
static int fdesc_inactive(struct vop_inactive_args *ap);
static int fdesc_lookup(struct vop_lookup_args *ap);
static int fdesc_open(struct vop_open_args *ap);
static int fdesc_print(struct vop_print_args *ap);
static int fdesc_readdir(struct vop_readdir_args *ap);
static int fdesc_reclaim(struct vop_reclaim_args *ap);
static int fdesc_poll(struct vop_poll_args *ap);
static int fdesc_setattr(struct vop_setattr_args *ap);
/*
* Initialise cache headers
*/
int
fdesc_init(vfsp)
struct vfsconf *vfsp;
{
fdhashtbl = hashinit(NFDCACHE, M_CACHE, &fdhash);
return (0);
}
int
fdesc_allocvp(ftype, ix, mp, vpp, td)
fdntype ftype;
int ix;
struct mount *mp;
struct vnode **vpp;
struct thread *td;
{
struct fdhashhead *fc;
struct fdescnode *fd;
int error = 0;
fc = FD_NHASH(ix);
loop:
LIST_FOREACH(fd, fc, fd_hash) {
if (fd->fd_ix == ix && fd->fd_vnode->v_mount == mp) {
if (vget(fd->fd_vnode, 0, td))
goto loop;
*vpp = fd->fd_vnode;
return (error);
}
}
/*
* otherwise lock the array while we call getnewvnode
* since that can block.
*/
if (fdcache_lock & FDL_LOCKED) {
fdcache_lock |= FDL_WANT;
(void) tsleep((caddr_t) &fdcache_lock, PINOD, "fdalvp", 0);
goto loop;
}
fdcache_lock |= FDL_LOCKED;
/*
* Do the MALLOC before the getnewvnode since doing so afterward
* might cause a bogus v_data pointer to get dereferenced
* elsewhere if MALLOC should block.
*/
MALLOC(fd, struct fdescnode *, sizeof(struct fdescnode), M_TEMP, M_WAITOK);
error = getnewvnode(VT_FDESC, mp, fdesc_vnodeop_p, vpp);
if (error) {
FREE(fd, M_TEMP);
goto out;
}
(*vpp)->v_data = fd;
fd->fd_vnode = *vpp;
fd->fd_type = ftype;
fd->fd_fd = -1;
fd->fd_ix = ix;
LIST_INSERT_HEAD(fc, fd, fd_hash);
out:
fdcache_lock &= ~FDL_LOCKED;
if (fdcache_lock & FDL_WANT) {
fdcache_lock &= ~FDL_WANT;
wakeup((caddr_t) &fdcache_lock);
}
return (error);
}
/*
* 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;
int error;
struct vnode *fvp;
if (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME) {
error = EROFS;
goto bad;
}
VOP_UNLOCK(dvp, 0, td);
if (cnp->cn_namelen == 1 && *pname == '.') {
*vpp = dvp;
VREF(dvp);
vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY, td);
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;
}
fd = 10 * fd + *pname++ - '0';
}
if ((error = fget(td, fd, &fp)) != 0)
goto bad;
error = fdesc_allocvp(Fdesc, FD_DESC+fd, dvp->v_mount, &fvp, td);
fdrop(fp, td);
if (error)
goto bad;
VTOFDESC(fvp)->fd_fd = fd;
vn_lock(fvp, LK_EXCLUSIVE | LK_RETRY, td);
*vpp = fvp;
return (0);
bad:
vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY, td);
*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 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;
struct thread *a_td;
} */ *ap;
{
struct vnode *vp = ap->a_vp;
struct vattr *vap = ap->a_vap;
struct file *fp;
struct stat stb;
u_int fd;
int error = 0;
switch (VTOFDESC(vp)->fd_type) {
case Froot:
VATTR_NULL(vap);
vap->va_mode = S_IRUSR|S_IXUSR|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH;
vap->va_type = VDIR;
vap->va_nlink = 2;
vap->va_size = DEV_BSIZE;
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_rdev = 0;
vap->va_bytes = 0;
break;
case Fdesc:
fd = VTOFDESC(vp)->fd_fd;
if ((error = fget(ap->a_td, fd, &fp)) != 0)
return (error);
bzero(&stb, sizeof(stb));
error = fo_stat(fp, &stb, ap->a_td);
fdrop(fp, ap->a_td);
if (error == 0) {
VATTR_NULL(vap);
vap->va_type = IFTOVT(stb.st_mode);
vap->va_mode = stb.st_mode;
#define FDRX (VREAD|VEXEC)
if (vap->va_type == VDIR)
vap->va_mode &= ~((FDRX)|(FDRX>>3)|(FDRX>>6));
#undef FDRX
vap->va_nlink = 1;
vap->va_flags = 0;
vap->va_bytes = stb.st_blocks * stb.st_blksize;
vap->va_fileid = VTOFDESC(vp)->fd_ix;
vap->va_size = stb.st_size;
vap->va_blocksize = stb.st_blksize;
vap->va_rdev = stb.st_rdev;
/*
* If no time data is provided, use the current time.
*/
if (stb.st_atimespec.tv_sec == 0 &&
stb.st_atimespec.tv_nsec == 0)
nanotime(&stb.st_atimespec);
if (stb.st_ctimespec.tv_sec == 0 &&
stb.st_ctimespec.tv_nsec == 0)
nanotime(&stb.st_ctimespec);
if (stb.st_mtimespec.tv_sec == 0 &&
stb.st_mtimespec.tv_nsec == 0)
nanotime(&stb.st_mtimespec);
vap->va_atime = stb.st_atimespec;
vap->va_mtime = stb.st_mtimespec;
vap->va_ctime = stb.st_ctimespec;
vap->va_uid = stb.st_uid;
vap->va_gid = stb.st_gid;
}
break;
default:
panic("fdesc_getattr");
break;
}
if (error == 0)
vp->v_type = vap->va_type;
return (error);
}
static int
fdesc_setattr(ap)
struct vop_setattr_args /* {
struct vnode *a_vp;
struct vattr *a_vap;
struct ucred *a_cred;
struct thread *a_td;
} */ *ap;
{
struct vattr *vap = ap->a_vap;
struct vnode *vp;
struct mount *mp;
struct file *fp;
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(ap->a_td->td_proc->p_fd, fd, &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 = (struct vnode *)fp->f_data;
if ((error = vn_start_write(vp, &mp, V_WAIT | PCATCH)) != 0) {
fdrop(fp, ap->a_td);
return (error);
}
error = VOP_SETATTR(vp, ap->a_vap, ap->a_cred, ap->a_td);
vn_finished_write(mp);
fdrop(fp, ap->a_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;
/*
* We don't allow exporting fdesc mounts, and currently local
* requests do not need cookies.
*/
if (ap->a_ncookies)
panic("fdesc_readdir: not hungry");
if (VTOFDESC(ap->a_vp)->fd_type != Froot)
panic("fdesc_readdir: not dir");
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_LOCK(fdp);
while (i < fdp->fd_nfiles + 2 && uio->uio_resid >= UIO_MX) {
switch (i) {
case 0: /* `.' */
case 1: /* `..' */
bzero((caddr_t)dp, UIO_MX);
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] == NULL) {
FILEDESC_UNLOCK(fdp);
goto done;
}
bzero((caddr_t) dp, UIO_MX);
dp->d_namlen = sprintf(dp->d_name, "%d", fcnt);
dp->d_reclen = UIO_MX;
dp->d_type = DT_UNKNOWN;
dp->d_fileno = i + FD_DESC;
break;
}
/*
* And ship to userland
*/
FILEDESC_UNLOCK(fdp);
error = uiomove((caddr_t) dp, UIO_MX, uio);
if (error)
goto done;
FILEDESC_LOCK(fdp);
i++;
fcnt++;
}
FILEDESC_UNLOCK(fdp);
done:
uio->uio_offset = i * UIO_MX;
return (error);
}
static int
fdesc_poll(ap)
struct vop_poll_args /* {
struct vnode *a_vp;
int a_events;
struct ucred *a_cred;
struct thread *a_td;
} */ *ap;
{
return seltrue(0, ap->a_events, ap->a_td);
}
static int
fdesc_inactive(ap)
struct vop_inactive_args /* {
struct vnode *a_vp;
struct thread *a_td;
} */ *ap;
{
struct vnode *vp = ap->a_vp;
/*
* Clear out the v_type field to avoid
* nasty things happening in vgone().
*/
VOP_UNLOCK(vp, 0, ap->a_td);
vp->v_type = VNON;
return (0);
}
static int
fdesc_reclaim(ap)
struct vop_reclaim_args /* {
struct vnode *a_vp;
} */ *ap;
{
struct vnode *vp = ap->a_vp;
struct fdescnode *fd = VTOFDESC(vp);
LIST_REMOVE(fd, fd_hash);
FREE(vp->v_data, M_TEMP);
vp->v_data = 0;
return (0);
}
/*
* Print out the contents of a /dev/fd vnode.
*/
/* ARGSUSED */
static int
fdesc_print(ap)
struct vop_print_args /* {
struct vnode *a_vp;
} */ *ap;
{
printf("tag VT_NON, fdesc vnode\n");
return (0);
}
static struct vnodeopv_entry_desc fdesc_vnodeop_entries[] = {
{ &vop_default_desc, (vop_t *) vop_defaultop },
{ &vop_access_desc, (vop_t *) vop_null },
{ &vop_getattr_desc, (vop_t *) fdesc_getattr },
{ &vop_inactive_desc, (vop_t *) fdesc_inactive },
{ &vop_lookup_desc, (vop_t *) fdesc_lookup },
{ &vop_open_desc, (vop_t *) fdesc_open },
{ &vop_pathconf_desc, (vop_t *) vop_stdpathconf },
{ &vop_poll_desc, (vop_t *) fdesc_poll },
{ &vop_print_desc, (vop_t *) fdesc_print },
{ &vop_readdir_desc, (vop_t *) fdesc_readdir },
{ &vop_reclaim_desc, (vop_t *) fdesc_reclaim },
{ &vop_setattr_desc, (vop_t *) fdesc_setattr },
{ &vop_lock_desc, (vop_t *) vop_stdlock },
{ &vop_unlock_desc, (vop_t *) vop_stdunlock },
{ &vop_islocked_desc, (vop_t *) vop_stdislocked },
{ NULL, NULL }
};
static struct vnodeopv_desc fdesc_vnodeop_opv_desc =
{ &fdesc_vnodeop_p, fdesc_vnodeop_entries };
VNODEOP_SET(fdesc_vnodeop_opv_desc);