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freebsd/sys/fs/pseudofs/pseudofs_vnops.c

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/*-
* Copyright (c) 2001 Dag-Erling Coïdan Smørgrav
* All rights reserved.
*
* 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
* in this position and unchanged.
* 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. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*
* $FreeBSD$
*/
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/ctype.h>
#include <sys/dirent.h>
#include <sys/lock.h>
#include <sys/mount.h>
#include <sys/mutex.h>
#include <sys/namei.h>
#include <sys/proc.h>
#include <sys/sbuf.h>
#include <sys/sx.h>
#include <sys/sysctl.h>
#include <sys/vnode.h>
#include <fs/pseudofs/pseudofs.h>
#include <fs/pseudofs/pseudofs_internal.h>
/*
* Verify permissions
*/
static int
pfs_access(struct vop_access_args *va)
{
struct vnode *vn = va->a_vp;
struct vattr vattr;
int error;
error = VOP_GETATTR(vn, &vattr, va->a_cred, va->a_p);
if (error)
return (error);
error = vaccess(vn->v_type, vattr.va_mode, vattr.va_uid,
vattr.va_gid, va->a_mode, va->a_cred, NULL);
return (error);
}
/*
* Close a file or directory
*/
static int
pfs_close(struct vop_close_args *va)
{
return (0);
}
/*
* Get file attributes
*/
static int
pfs_getattr(struct vop_getattr_args *va)
{
struct vnode *vn = va->a_vp;
struct pfs_vdata *pvd = (struct pfs_vdata *)vn->v_data;
struct pfs_node *pn = pvd->pvd_pn;
struct vattr *vap = va->a_vap;
VATTR_NULL(vap);
vap->va_type = vn->v_type;
vap->va_mode = pn->pn_mode;
vap->va_fileid = pn->pn_fileno;
vap->va_flags = 0;
vap->va_blocksize = PAGE_SIZE;
vap->va_bytes = vap->va_size = 0;
vap->va_fsid = vn->v_mount->mnt_stat.f_fsid.val[0];
vap->va_nlink = 1;
nanotime(&vap->va_ctime);
vap->va_atime = vap->va_mtime = vap->va_ctime;
vap->va_uid = pn->pn_uid;
vap->va_gid = pn->pn_gid;
return (0);
}
/*
* Look up a file or directory
*/
static int
pfs_lookup(struct vop_lookup_args *va)
{
struct vnode *vn = va->a_dvp;
struct vnode **vpp = va->a_vpp;
struct componentname *cnp = va->a_cnp;
struct pfs_vdata *pvd = (struct pfs_vdata *)vn->v_data;
struct pfs_node *pd = pvd->pvd_pn;
struct pfs_node *pn, *pdn = NULL;
pid_t pid = pvd->pvd_pid;
char *pname;
int error, i, namelen;
if (vn->v_type != VDIR)
return (ENOTDIR);
/* don't support CREATE, RENAME or DELETE */
if (cnp->cn_nameiop != LOOKUP)
return (EROFS);
/* shortcut */
if (cnp->cn_namelen >= PFS_NAMELEN)
return (ENOENT);
/* self */
namelen = cnp->cn_namelen;
pname = cnp->cn_nameptr;
if (namelen == 1 && *pname == '.') {
pn = pd;
*vpp = vn;
VREF(vn);
goto got_vnode;
}
/* parent */
if (cnp->cn_flags & ISDOTDOT) {
if (pd->pn_type == pfstype_root)
return (EIO);
KASSERT(pd->pn_parent, ("non-root directory has no parent"));
/*
* This one is tricky. Descendents of procdir nodes
* inherit their parent's process affinity, but
* there's no easy reverse mapping. For simplicity,
* we assume that if this node is a procdir, its
* parent isn't (which is correct as long as
* descendents of procdir nodes are never procdir
* nodes themselves)
*/
if (pd->pn_type == pfstype_procdir)
pid = NO_PID;
return pfs_vncache_alloc(vn->v_mount, vpp, pd->pn_parent, pid);
}
/* named node */
for (pn = pd->pn_nodes; pn->pn_type; ++pn)
if (pn->pn_type == pfstype_procdir)
pdn = pn;
else if (pn->pn_name[namelen] == '\0'
&& bcmp(pname, pn->pn_name, namelen) == 0)
goto got_pnode;
/* process dependent node */
if ((pn = pdn) != NULL) {
pid = 0;
for (pid = 0, i = 0; i < namelen && isdigit(pname[i]); ++i)
if ((pid = pid * 10 + pname[i] - '0') > PID_MAX)
break;
if (i == cnp->cn_namelen)
goto got_pnode;
}
return (ENOENT);
got_pnode:
if (!pn->pn_parent)
pn->pn_parent = pd;
error = pfs_vncache_alloc(vn->v_mount, vpp, pn, pid);
if (error)
return error;
got_vnode:
if (cnp->cn_flags & MAKEENTRY)
cache_enter(vn, *vpp, cnp);
return (0);
}
/*
* Open a file or directory.
*/
static int
pfs_open(struct vop_open_args *va)
{
/* XXX */
return (0);
}
/*
* Read from a file
*/
static int
pfs_read(struct vop_read_args *va)
{
struct vnode *vn = va->a_vp;
struct pfs_vdata *pvd = (struct pfs_vdata *)vn->v_data;
struct pfs_node *pn = pvd->pvd_pn;
struct uio *uio = va->a_uio;
struct proc *proc = NULL;
struct sbuf *sb = NULL;
char *ps;
int error, xlen;
if (vn->v_type != VREG)
return (EINVAL);
if (pvd->pvd_pid != NO_PID) {
if ((proc = pfind(pvd->pvd_pid)) == NULL)
return (EIO);
_PHOLD(proc);
PROC_UNLOCK(proc);
}
sb = sbuf_new(sb, NULL, uio->uio_offset + uio->uio_resid, 0);
if (sb == NULL) {
if (proc != NULL)
PRELE(proc);
return (EIO);
}
error = (pn->pn_func)(curproc, proc, pn, sb);
if (proc != NULL)
PRELE(proc);
if (error) {
sbuf_delete(sb);
return (error);
}
/* XXX we should possibly detect and handle overflows */
sbuf_finish(sb);
ps = sbuf_data(sb) + uio->uio_offset;
xlen = sbuf_len(sb) - uio->uio_offset;
xlen = imin(xlen, uio->uio_resid);
error = (xlen <= 0 ? 0 : uiomove(ps, xlen, uio));
sbuf_delete(sb);
return (error);
}
/*
* Iterate through directory entries
*/
static int
pfs_iterate(struct pfs_info *pi, struct pfs_node **pn, struct proc **p)
{
if ((*pn)->pn_type == pfstype_none)
return (-1);
if ((*pn)->pn_type != pfstype_procdir)
++*pn;
while ((*pn)->pn_type == pfstype_procdir) {
if (*p == NULL)
*p = LIST_FIRST(&allproc);
else
*p = LIST_NEXT(*p, p_list);
if (*p != NULL)
return (0);
++*pn;
}
if ((*pn)->pn_type == pfstype_none)
return (-1);
return (0);
}
/*
* Return directory entries.
*/
static int
pfs_readdir(struct vop_readdir_args *va)
{
struct vnode *vn = va->a_vp;
struct pfs_info *pi = (struct pfs_info *)vn->v_mount->mnt_data;
struct pfs_vdata *pvd = (struct pfs_vdata *)vn->v_data;
struct pfs_node *pd = pvd->pvd_pn;
struct pfs_node *pn;
struct dirent entry;
struct uio *uio;
struct proc *p;
off_t offset;
int error, i, resid;
if (vn->v_type != VDIR)
return (ENOTDIR);
uio = va->a_uio;
/* only allow reading entire entries */
offset = uio->uio_offset;
resid = uio->uio_resid;
if (offset < 0 || offset % PFS_DELEN != 0 || resid < PFS_DELEN)
return (EINVAL);
/* skip unwanted entries */
sx_slock(&allproc_lock);
for (pn = pd->pn_nodes, p = NULL; offset > 0; offset -= PFS_DELEN)
if (pfs_iterate(pi, &pn, &p) == -1)
break;
/* fill in entries */
entry.d_reclen = PFS_DELEN;
while (pfs_iterate(pi, &pn, &p) != -1 && resid > 0) {
if (!pn->pn_parent)
pn->pn_parent = pd;
if (!pn->pn_fileno)
pfs_fileno_alloc(pi, pn);
if (pvd->pvd_pid != NO_PID)
entry.d_fileno = pn->pn_fileno * NO_PID + pvd->pvd_pid;
else
entry.d_fileno = pn->pn_fileno;
/* PFS_DELEN was picked to fit PFS_NAMLEN */
for (i = 0; i < PFS_NAMELEN - 1 && pn->pn_name[i] != '\0'; ++i)
entry.d_name[i] = pn->pn_name[i];
entry.d_name[i] = 0;
entry.d_namlen = i;
switch (pn->pn_type) {
case pfstype_procdir:
KASSERT(p != NULL,
("reached procdir node with p == NULL"));
entry.d_fileno = pn->pn_fileno * NO_PID + p->p_pid;
entry.d_namlen = snprintf(entry.d_name,
PFS_NAMELEN, "%d", p->p_pid);
/* fall through */
case pfstype_root:
case pfstype_dir:
case pfstype_this:
case pfstype_parent:
entry.d_type = DT_DIR;
break;
case pfstype_file:
entry.d_type = DT_REG;
break;
case pfstype_symlink:
entry.d_type = DT_LNK;
break;
default:
sx_sunlock(&allproc_lock);
panic("%s has unexpected node type: %d", pn->pn_name, pn->pn_type);
}
if ((error = uiomove((caddr_t)&entry, PFS_DELEN, uio))) {
sx_sunlock(&allproc_lock);
return (error);
}
offset += PFS_DELEN;
resid -= PFS_DELEN;
}
sx_sunlock(&allproc_lock);
uio->uio_offset += offset;
return (0);
}
/*
* Read a symbolic link
*/
static int
pfs_readlink(struct vop_readlink_args *va)
{
struct vnode *vn = va->a_vp;
struct pfs_vdata *pvd = (struct pfs_vdata *)vn->v_data;
struct pfs_node *pn = pvd->pvd_pn;
struct uio *uio = va->a_uio;
struct proc *proc = NULL;
char buf[MAXPATHLEN], *ps;
struct sbuf sb;
int error, xlen;
if (vn->v_type != VLNK)
return (EINVAL);
if (pvd->pvd_pid != NO_PID) {
if ((proc = pfind(pvd->pvd_pid)) == NULL)
return (EIO);
_PHOLD(proc);
PROC_UNLOCK(proc);
}
/* sbuf_new() can't fail with a static buffer */
sbuf_new(&sb, buf, sizeof buf, 0);
error = (pn->pn_func)(curproc, proc, pn, &sb);
if (proc != NULL)
PRELE(proc);
if (error) {
sbuf_delete(&sb);
return (error);
}
/* XXX we should detect and handle overflows */
sbuf_finish(&sb);
ps = sbuf_data(&sb) + uio->uio_offset;
xlen = sbuf_len(&sb) - uio->uio_offset;
xlen = imin(xlen, uio->uio_resid);
error = (xlen <= 0 ? 0 : uiomove(ps, xlen, uio));
sbuf_delete(&sb);
return (error);
}
/*
* Reclaim a vnode
*/
static int
pfs_reclaim(struct vop_reclaim_args *va)
{
return (pfs_vncache_free(va->a_vp));
}
/*
* Set attributes
*/
static int
pfs_setattr(struct vop_setattr_args *va)
{
if (va->a_vap->va_flags != (u_long)VNOVAL)
return (EOPNOTSUPP);
/* XXX it's a bit more complex than that, really... */
return (0);
}
/*
* Dummy operations
*/
static int pfs_erofs(void *va) { return (EROFS); }
#if 0
static int pfs_null(void *va) { return (0); }
#endif
/*
* Vnode operations
*/
vop_t **pfs_vnodeop_p;
static struct vnodeopv_entry_desc pfs_vnodeop_entries[] = {
{ &vop_default_desc, (vop_t *)vop_defaultop },
{ &vop_access_desc, (vop_t *)pfs_access },
{ &vop_close_desc, (vop_t *)pfs_close },
{ &vop_create_desc, (vop_t *)pfs_erofs },
{ &vop_getattr_desc, (vop_t *)pfs_getattr },
{ &vop_link_desc, (vop_t *)pfs_erofs },
{ &vop_lookup_desc, (vop_t *)pfs_lookup },
{ &vop_mkdir_desc, (vop_t *)pfs_erofs },
{ &vop_open_desc, (vop_t *)pfs_open },
{ &vop_read_desc, (vop_t *)pfs_read },
{ &vop_readdir_desc, (vop_t *)pfs_readdir },
{ &vop_readlink_desc, (vop_t *)pfs_readlink },
{ &vop_reclaim_desc, (vop_t *)pfs_reclaim },
{ &vop_remove_desc, (vop_t *)pfs_erofs },
{ &vop_rename_desc, (vop_t *)pfs_erofs },
{ &vop_rmdir_desc, (vop_t *)pfs_erofs },
{ &vop_setattr_desc, (vop_t *)pfs_setattr },
{ &vop_symlink_desc, (vop_t *)pfs_erofs },
{ &vop_write_desc, (vop_t *)pfs_erofs },
/* XXX I've probably forgotten a few that need pfs_erofs */
{ NULL, (vop_t *)NULL }
};
static struct vnodeopv_desc pfs_vnodeop_opv_desc =
{ &pfs_vnodeop_p, pfs_vnodeop_entries };
VNODEOP_SET(pfs_vnodeop_opv_desc);
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