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NetBSD/sys/fs/tmpfs/tmpfs_subr.c
thorpej 4f3d5a9cc0 TRUE -> true, FALSE -> false
2007-02-22 06:34:42 +00:00

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/* $NetBSD: tmpfs_subr.c,v 1.34 2007/02/22 06:37:00 thorpej Exp $ */
/*
* Copyright (c) 2005, 2006 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Julio M. Merino Vidal, developed as part of Google's Summer of Code
* 2005 program.
*
* 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 NetBSD
* Foundation, Inc. and its contributors.
* 4. Neither the name of The NetBSD Foundation 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*/
/*
* Efficient memory file system supporting functions.
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: tmpfs_subr.c,v 1.34 2007/02/22 06:37:00 thorpej Exp $");
#include <sys/param.h>
#include <sys/dirent.h>
#include <sys/event.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <sys/systm.h>
#include <sys/swap.h>
#include <sys/vnode.h>
#include <sys/kauth.h>
#include <uvm/uvm.h>
#include <miscfs/specfs/specdev.h>
#include <fs/tmpfs/tmpfs.h>
#include <fs/tmpfs/tmpfs_fifoops.h>
#include <fs/tmpfs/tmpfs_specops.h>
#include <fs/tmpfs/tmpfs_vnops.h>
/* --------------------------------------------------------------------- */
/*
* Allocates a new node of type 'type' inside the 'tmp' mount point, with
* its owner set to 'uid', its group to 'gid' and its mode set to 'mode',
* using the credentials of the process 'p'.
*
* If the node type is set to 'VDIR', then the parent parameter must point
* to the parent directory of the node being created. It may only be NULL
* while allocating the root node.
*
* If the node type is set to 'VBLK' or 'VCHR', then the rdev parameter
* specifies the device the node represents.
*
* If the node type is set to 'VLNK', then the parameter target specifies
* the file name of the target file for the symbolic link that is being
* created.
*
* Note that new nodes are retrieved from the available list if it has
* items or, if it is empty, from the node pool as long as there is enough
* space to create them.
*
* Returns zero on success or an appropriate error code on failure.
*/
int
tmpfs_alloc_node(struct tmpfs_mount *tmp, enum vtype type,
uid_t uid, gid_t gid, mode_t mode, struct tmpfs_node *parent,
char *target, dev_t rdev, struct proc *p, struct tmpfs_node **node)
{
struct tmpfs_node *nnode;
/* If the root directory of the 'tmp' file system is not yet
* allocated, this must be the request to do it. */
KASSERT(IMPLIES(tmp->tm_root == NULL, parent == NULL && type == VDIR));
KASSERT(IFF(type == VLNK, target != NULL));
KASSERT(IFF(type == VBLK || type == VCHR, rdev != VNOVAL));
KASSERT(uid != VNOVAL && gid != VNOVAL && mode != VNOVAL);
nnode = NULL;
if (LIST_EMPTY(&tmp->tm_nodes_avail)) {
KASSERT(tmp->tm_nodes_last <= tmp->tm_nodes_max);
if (tmp->tm_nodes_last == tmp->tm_nodes_max)
return ENOSPC;
nnode =
(struct tmpfs_node *)TMPFS_POOL_GET(&tmp->tm_node_pool, 0);
if (nnode == NULL)
return ENOSPC;
nnode->tn_id = tmp->tm_nodes_last++;
nnode->tn_gen = arc4random();
} else {
nnode = LIST_FIRST(&tmp->tm_nodes_avail);
LIST_REMOVE(nnode, tn_entries);
nnode->tn_gen++;
}
KASSERT(nnode != NULL);
LIST_INSERT_HEAD(&tmp->tm_nodes_used, nnode, tn_entries);
/* Generic initialization. */
nnode->tn_type = type;
nnode->tn_size = 0;
nnode->tn_status = 0;
nnode->tn_flags = 0;
nnode->tn_links = 0;
getnanotime(&nnode->tn_atime);
nnode->tn_birthtime = nnode->tn_ctime = nnode->tn_mtime =
nnode->tn_atime;
nnode->tn_uid = uid;
nnode->tn_gid = gid;
nnode->tn_mode = mode;
nnode->tn_lockf = NULL;
nnode->tn_vnode = NULL;
/* Type-specific initialization. */
switch (nnode->tn_type) {
case VBLK:
case VCHR:
nnode->tn_spec.tn_dev.tn_rdev = rdev;
break;
case VDIR:
TAILQ_INIT(&nnode->tn_spec.tn_dir.tn_dir);
nnode->tn_spec.tn_dir.tn_parent =
(parent == NULL) ? nnode : parent;
nnode->tn_spec.tn_dir.tn_readdir_lastn = 0;
nnode->tn_spec.tn_dir.tn_readdir_lastp = NULL;
nnode->tn_links++;
nnode->tn_spec.tn_dir.tn_parent->tn_links++;
if (parent != NULL) {
KASSERT(parent->tn_vnode != NULL);
VN_KNOTE(parent->tn_vnode, NOTE_LINK);
}
break;
case VFIFO:
/* FALLTHROUGH */
case VSOCK:
break;
case VLNK:
KASSERT(strlen(target) < MAXPATHLEN);
nnode->tn_size = strlen(target);
nnode->tn_spec.tn_lnk.tn_link =
tmpfs_str_pool_get(&tmp->tm_str_pool, nnode->tn_size, 0);
if (nnode->tn_spec.tn_lnk.tn_link == NULL) {
nnode->tn_type = VNON;
tmpfs_free_node(tmp, nnode);
return ENOSPC;
}
memcpy(nnode->tn_spec.tn_lnk.tn_link, target, nnode->tn_size);
break;
case VREG:
nnode->tn_spec.tn_reg.tn_aobj =
uao_create(INT32_MAX - PAGE_SIZE, 0);
nnode->tn_spec.tn_reg.tn_aobj_pages = 0;
break;
default:
KASSERT(0);
}
*node = nnode;
return 0;
}
/* --------------------------------------------------------------------- */
/*
* Destroys the node pointed to by node from the file system 'tmp'.
* If the node does not belong to the given mount point, the results are
* unpredicted.
*
* If the node references a directory; no entries are allowed because
* their removal could need a recursive algorithm, something forbidden in
* kernel space. Furthermore, there is not need to provide such
* functionality (recursive removal) because the only primitives offered
* to the user are the removal of empty directories and the deletion of
* individual files.
*
* Note that nodes are not really deleted; in fact, when a node has been
* allocated, it cannot be deleted during the whole life of the file
* system. Instead, they are moved to the available list and remain there
* until reused.
*/
void
tmpfs_free_node(struct tmpfs_mount *tmp, struct tmpfs_node *node)
{
ino_t id;
unsigned long gen;
size_t pages;
switch (node->tn_type) {
case VNON:
/* Do not do anything. VNON is provided to let the
* allocation routine clean itself easily by avoiding
* duplicating code in it. */
/* FALLTHROUGH */
case VBLK:
/* FALLTHROUGH */
case VCHR:
/* FALLTHROUGH */
case VDIR:
/* FALLTHROUGH */
case VFIFO:
/* FALLTHROUGH */
case VSOCK:
pages = 0;
break;
case VLNK:
tmpfs_str_pool_put(&tmp->tm_str_pool,
node->tn_spec.tn_lnk.tn_link, node->tn_size);
pages = 0;
break;
case VREG:
if (node->tn_spec.tn_reg.tn_aobj != NULL)
uao_detach(node->tn_spec.tn_reg.tn_aobj);
pages = node->tn_spec.tn_reg.tn_aobj_pages;
break;
default:
KASSERT(0);
pages = 0; /* Shut up gcc when !DIAGNOSTIC. */
break;
}
tmp->tm_pages_used -= pages;
LIST_REMOVE(node, tn_entries);
id = node->tn_id;
gen = node->tn_gen;
memset(node, 0, sizeof(struct tmpfs_node));
node->tn_id = id;
node->tn_type = VNON;
node->tn_gen = gen;
LIST_INSERT_HEAD(&tmp->tm_nodes_avail, node, tn_entries);
}
/* --------------------------------------------------------------------- */
/*
* Allocates a new directory entry for the node node with a name of name.
* The new directory entry is returned in *de.
*
* The link count of node is increased by one to reflect the new object
* referencing it. This takes care of notifying kqueue listeners about
* this change.
*
* Returns zero on success or an appropriate error code on failure.
*/
int
tmpfs_alloc_dirent(struct tmpfs_mount *tmp, struct tmpfs_node *node,
const char *name, uint16_t len, struct tmpfs_dirent **de)
{
struct tmpfs_dirent *nde;
nde = (struct tmpfs_dirent *)TMPFS_POOL_GET(&tmp->tm_dirent_pool, 0);
if (nde == NULL)
return ENOSPC;
nde->td_name = tmpfs_str_pool_get(&tmp->tm_str_pool, len, 0);
if (nde->td_name == NULL) {
TMPFS_POOL_PUT(&tmp->tm_dirent_pool, nde);
return ENOSPC;
}
nde->td_namelen = len;
memcpy(nde->td_name, name, len);
nde->td_node = node;
node->tn_links++;
if (node->tn_links > 1 && node->tn_vnode != NULL)
VN_KNOTE(node->tn_vnode, NOTE_LINK);
*de = nde;
return 0;
}
/* --------------------------------------------------------------------- */
/*
* Frees a directory entry. It is the caller's responsibility to destroy
* the node referenced by it if needed.
*
* The link count of node is decreased by one to reflect the removal of an
* object that referenced it. This only happens if 'node_exists' is true;
* otherwise the function will not access the node referred to by the
* directory entry, as it may already have been released from the outside.
*
* Interested parties (kqueue) are notified of the link count change; note
* that this can include both the node pointed to by the directory entry
* as well as its parent.
*/
void
tmpfs_free_dirent(struct tmpfs_mount *tmp, struct tmpfs_dirent *de,
bool node_exists)
{
if (node_exists) {
struct tmpfs_node *node;
node = de->td_node;
KASSERT(node->tn_links > 0);
node->tn_links--;
if (node->tn_vnode != NULL)
VN_KNOTE(node->tn_vnode, node->tn_links == 0 ?
NOTE_DELETE : NOTE_LINK);
if (node->tn_type == VDIR)
VN_KNOTE(node->tn_spec.tn_dir.tn_parent->tn_vnode,
NOTE_LINK);
}
tmpfs_str_pool_put(&tmp->tm_str_pool, de->td_name, de->td_namelen);
TMPFS_POOL_PUT(&tmp->tm_dirent_pool, de);
}
/* --------------------------------------------------------------------- */
/*
* Allocates a new vnode for the node node or returns a new reference to
* an existing one if the node had already a vnode referencing it. The
* resulting locked vnode is returned in *vpp.
*
* Returns zero on success or an appropriate error code on failure.
*/
int
tmpfs_alloc_vp(struct mount *mp, struct tmpfs_node *node, struct vnode **vpp)
{
int error;
struct vnode *nvp;
struct vnode *vp;
vp = NULL;
if (node->tn_vnode != NULL) {
vp = node->tn_vnode;
vget(vp, LK_EXCLUSIVE | LK_RETRY);
error = 0;
goto out;
}
/* Get a new vnode and associate it with our node. */
error = getnewvnode(VT_TMPFS, mp, tmpfs_vnodeop_p, &vp);
if (error != 0)
goto out;
KASSERT(vp != NULL);
error = vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
if (error != 0) {
vp->v_data = NULL;
ungetnewvnode(vp);
vp = NULL;
goto out;
}
vp->v_data = node;
vp->v_type = node->tn_type;
/* Type-specific initialization. */
switch (node->tn_type) {
case VBLK:
/* FALLTHROUGH */
case VCHR:
vp->v_op = tmpfs_specop_p;
nvp = checkalias(vp, node->tn_spec.tn_dev.tn_rdev, mp);
if (nvp != NULL) {
/* Discard unneeded vnode, but save its inode. */
nvp->v_data = vp->v_data;
vp->v_data = NULL;
/* XXX spec_vnodeops has no locking, so we have to
* do it explicitly. */
VOP_UNLOCK(vp, 0);
vp->v_op = spec_vnodeop_p;
vp->v_flag &= ~VLOCKSWORK;
vrele(vp);
vgone(vp);
/* Reinitialize aliased node. */
vp = nvp;
error = vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
if (error != 0) {
vp->v_data = NULL;
vp = NULL;
goto out;
}
}
break;
case VDIR:
vp->v_flag = node->tn_spec.tn_dir.tn_parent == node ? VROOT : 0;
break;
case VFIFO:
vp->v_op = tmpfs_fifoop_p;
break;
case VLNK:
/* FALLTHROUGH */
case VREG:
/* FALLTHROUGH */
case VSOCK:
break;
default:
KASSERT(0);
}
uvm_vnp_setsize(vp, node->tn_size);
error = 0;
out:
*vpp = node->tn_vnode = vp;
KASSERT(IFF(error == 0, *vpp != NULL && VOP_ISLOCKED(*vpp)));
KASSERT(*vpp == node->tn_vnode);
return error;
}
/* --------------------------------------------------------------------- */
/*
* Destroys the association between the vnode vp and the node it
* references.
*/
void
tmpfs_free_vp(struct vnode *vp)
{
struct tmpfs_node *node;
node = VP_TO_TMPFS_NODE(vp);
node->tn_vnode = NULL;
vp->v_data = NULL;
}
/* --------------------------------------------------------------------- */
/*
* Allocates a new file of type 'type' and adds it to the parent directory
* 'dvp'; this addition is done using the component name given in 'cnp'.
* The ownership of the new file is automatically assigned based on the
* credentials of the caller (through 'cnp'), the group is set based on
* the parent directory and the mode is determined from the 'vap' argument.
* If successful, *vpp holds a vnode to the newly created file and zero
* is returned. Otherwise *vpp is NULL and the function returns an
* appropriate error code.
*/
int
tmpfs_alloc_file(struct vnode *dvp, struct vnode **vpp, struct vattr *vap,
struct componentname *cnp, char *target)
{
int error;
struct tmpfs_dirent *de;
struct tmpfs_mount *tmp;
struct tmpfs_node *dnode;
struct tmpfs_node *node;
struct tmpfs_node *parent;
KASSERT(VOP_ISLOCKED(dvp));
KASSERT(cnp->cn_flags & HASBUF);
tmp = VFS_TO_TMPFS(dvp->v_mount);
dnode = VP_TO_TMPFS_DIR(dvp);
*vpp = NULL;
/* If the entry we are creating is a directory, we cannot overflow
* the number of links of its parent, because it will get a new
* link. */
if (vap->va_type == VDIR) {
/* Ensure that we do not overflow the maximum number of links
* imposed by the system. */
KASSERT(dnode->tn_links <= LINK_MAX);
if (dnode->tn_links == LINK_MAX) {
error = EMLINK;
goto out;
}
parent = dnode;
} else
parent = NULL;
/* Allocate a node that represents the new file. */
error = tmpfs_alloc_node(tmp, vap->va_type, kauth_cred_geteuid(cnp->cn_cred),
dnode->tn_gid, vap->va_mode, parent, target, vap->va_rdev,
cnp->cn_lwp->l_proc, &node);
if (error != 0)
goto out;
/* Allocate a directory entry that points to the new file. */
error = tmpfs_alloc_dirent(tmp, node, cnp->cn_nameptr, cnp->cn_namelen,
&de);
if (error != 0) {
tmpfs_free_node(tmp, node);
goto out;
}
/* Allocate a vnode for the new file. */
error = tmpfs_alloc_vp(dvp->v_mount, node, vpp);
if (error != 0) {
tmpfs_free_dirent(tmp, de, true);
tmpfs_free_node(tmp, node);
goto out;
}
/* Now that all required items are allocated, we can proceed to
* insert the new node into the directory, an operation that
* cannot fail. */
tmpfs_dir_attach(dvp, de);
out:
if (error != 0 || !(cnp->cn_flags & SAVESTART))
PNBUF_PUT(cnp->cn_pnbuf);
vput(dvp);
KASSERT(!VOP_ISLOCKED(dvp));
KASSERT(IFF(error == 0, *vpp != NULL));
return error;
}
/* --------------------------------------------------------------------- */
/*
* Attaches the directory entry de to the directory represented by vp.
* Note that this does not change the link count of the node pointed by
* the directory entry, as this is done by tmpfs_alloc_dirent.
*
* As the "parent" directory changes, interested parties are notified of
* a write to it.
*/
void
tmpfs_dir_attach(struct vnode *vp, struct tmpfs_dirent *de)
{
struct tmpfs_node *dnode;
dnode = VP_TO_TMPFS_DIR(vp);
TAILQ_INSERT_TAIL(&dnode->tn_spec.tn_dir.tn_dir, de, td_entries);
dnode->tn_size += sizeof(struct tmpfs_dirent);
dnode->tn_status |= TMPFS_NODE_ACCESSED | TMPFS_NODE_CHANGED | \
TMPFS_NODE_MODIFIED;
uvm_vnp_setsize(vp, dnode->tn_size);
VN_KNOTE(vp, NOTE_WRITE);
}
/* --------------------------------------------------------------------- */
/*
* Detaches the directory entry de from the directory represented by vp.
* Note that this does not change the link count of the node pointed by
* the directory entry, as this is done by tmpfs_free_dirent.
*
* As the "parent" directory changes, interested parties are notified of
* a write to it.
*/
void
tmpfs_dir_detach(struct vnode *vp, struct tmpfs_dirent *de)
{
struct tmpfs_node *dnode;
KASSERT(VOP_ISLOCKED(vp));
dnode = VP_TO_TMPFS_DIR(vp);
if (dnode->tn_spec.tn_dir.tn_readdir_lastp == de) {
dnode->tn_spec.tn_dir.tn_readdir_lastn = 0;
dnode->tn_spec.tn_dir.tn_readdir_lastp = NULL;
}
TAILQ_REMOVE(&dnode->tn_spec.tn_dir.tn_dir, de, td_entries);
dnode->tn_size -= sizeof(struct tmpfs_dirent);
dnode->tn_status |= TMPFS_NODE_ACCESSED | TMPFS_NODE_CHANGED | \
TMPFS_NODE_MODIFIED;
uvm_vnp_setsize(vp, dnode->tn_size);
VN_KNOTE(vp, NOTE_WRITE);
}
/* --------------------------------------------------------------------- */
/*
* Looks for a directory entry in the directory represented by node.
* 'cnp' describes the name of the entry to look for. Note that the .
* and .. components are not allowed as they do not physically exist
* within directories.
*
* Returns a pointer to the entry when found, otherwise NULL.
*/
struct tmpfs_dirent *
tmpfs_dir_lookup(struct tmpfs_node *node, struct componentname *cnp)
{
bool found;
struct tmpfs_dirent *de;
KASSERT(IMPLIES(cnp->cn_namelen == 1, cnp->cn_nameptr[0] != '.'));
KASSERT(IMPLIES(cnp->cn_namelen == 2, !(cnp->cn_nameptr[0] == '.' &&
cnp->cn_nameptr[1] == '.')));
TMPFS_VALIDATE_DIR(node);
node->tn_status |= TMPFS_NODE_ACCESSED;
found = 0;
TAILQ_FOREACH(de, &node->tn_spec.tn_dir.tn_dir, td_entries) {
KASSERT(cnp->cn_namelen < 0xffff);
if (de->td_namelen == (uint16_t)cnp->cn_namelen &&
memcmp(de->td_name, cnp->cn_nameptr, de->td_namelen) == 0) {
found = 1;
break;
}
}
return found ? de : NULL;
}
/* --------------------------------------------------------------------- */
/*
* Helper function for tmpfs_readdir. Creates a '.' entry for the given
* directory and returns it in the uio space. The function returns 0
* on success, -1 if there was not enough space in the uio structure to
* hold the directory entry or an appropriate error code if another
* error happens.
*/
int
tmpfs_dir_getdotdent(struct tmpfs_node *node, struct uio *uio)
{
int error;
struct dirent dent;
TMPFS_VALIDATE_DIR(node);
KASSERT(uio->uio_offset == TMPFS_DIRCOOKIE_DOT);
dent.d_fileno = node->tn_id;
dent.d_type = DT_DIR;
dent.d_namlen = 1;
dent.d_name[0] = '.';
dent.d_name[1] = '\0';
dent.d_reclen = _DIRENT_SIZE(&dent);
if (dent.d_reclen > uio->uio_resid)
error = -1;
else {
error = uiomove(&dent, dent.d_reclen, uio);
if (error == 0)
uio->uio_offset = TMPFS_DIRCOOKIE_DOTDOT;
}
node->tn_status |= TMPFS_NODE_ACCESSED;
return error;
}
/* --------------------------------------------------------------------- */
/*
* Helper function for tmpfs_readdir. Creates a '..' entry for the given
* directory and returns it in the uio space. The function returns 0
* on success, -1 if there was not enough space in the uio structure to
* hold the directory entry or an appropriate error code if another
* error happens.
*/
int
tmpfs_dir_getdotdotdent(struct tmpfs_node *node, struct uio *uio)
{
int error;
struct dirent dent;
TMPFS_VALIDATE_DIR(node);
KASSERT(uio->uio_offset == TMPFS_DIRCOOKIE_DOTDOT);
dent.d_fileno = node->tn_spec.tn_dir.tn_parent->tn_id;
dent.d_type = DT_DIR;
dent.d_namlen = 2;
dent.d_name[0] = '.';
dent.d_name[1] = '.';
dent.d_name[2] = '\0';
dent.d_reclen = _DIRENT_SIZE(&dent);
if (dent.d_reclen > uio->uio_resid)
error = -1;
else {
error = uiomove(&dent, dent.d_reclen, uio);
if (error == 0) {
struct tmpfs_dirent *de;
de = TAILQ_FIRST(&node->tn_spec.tn_dir.tn_dir);
if (de == NULL)
uio->uio_offset = TMPFS_DIRCOOKIE_EOF;
else
uio->uio_offset = tmpfs_dircookie(de);
}
}
node->tn_status |= TMPFS_NODE_ACCESSED;
return error;
}
/* --------------------------------------------------------------------- */
/*
* Lookup a directory entry by its associated cookie.
*/
struct tmpfs_dirent *
tmpfs_dir_lookupbycookie(struct tmpfs_node *node, off_t cookie)
{
struct tmpfs_dirent *de;
if (cookie == node->tn_spec.tn_dir.tn_readdir_lastn &&
node->tn_spec.tn_dir.tn_readdir_lastp != NULL) {
return node->tn_spec.tn_dir.tn_readdir_lastp;
}
TAILQ_FOREACH(de, &node->tn_spec.tn_dir.tn_dir, td_entries) {
if (tmpfs_dircookie(de) == cookie) {
break;
}
}
return de;
}
/* --------------------------------------------------------------------- */
/*
* Helper function for tmpfs_readdir. Returns as much directory entries
* as can fit in the uio space. The read starts at uio->uio_offset.
* The function returns 0 on success, -1 if there was not enough space
* in the uio structure to hold the directory entry or an appropriate
* error code if another error happens.
*/
int
tmpfs_dir_getdents(struct tmpfs_node *node, struct uio *uio, off_t *cntp)
{
int error;
off_t startcookie;
struct tmpfs_dirent *de;
TMPFS_VALIDATE_DIR(node);
/* Locate the first directory entry we have to return. We have cached
* the last readdir in the node, so use those values if appropriate.
* Otherwise do a linear scan to find the requested entry. */
startcookie = uio->uio_offset;
KASSERT(startcookie != TMPFS_DIRCOOKIE_DOT);
KASSERT(startcookie != TMPFS_DIRCOOKIE_DOTDOT);
if (startcookie == TMPFS_DIRCOOKIE_EOF) {
return 0;
} else {
de = tmpfs_dir_lookupbycookie(node, startcookie);
}
if (de == NULL) {
return EINVAL;
}
/* Read as much entries as possible; i.e., until we reach the end of
* the directory or we exhaust uio space. */
do {
struct dirent d;
/* Create a dirent structure representing the current
* tmpfs_node and fill it. */
d.d_fileno = de->td_node->tn_id;
switch (de->td_node->tn_type) {
case VBLK:
d.d_type = DT_BLK;
break;
case VCHR:
d.d_type = DT_CHR;
break;
case VDIR:
d.d_type = DT_DIR;
break;
case VFIFO:
d.d_type = DT_FIFO;
break;
case VLNK:
d.d_type = DT_LNK;
break;
case VREG:
d.d_type = DT_REG;
break;
case VSOCK:
d.d_type = DT_SOCK;
break;
default:
KASSERT(0);
}
d.d_namlen = de->td_namelen;
KASSERT(de->td_namelen < sizeof(d.d_name));
(void)memcpy(d.d_name, de->td_name, de->td_namelen);
d.d_name[de->td_namelen] = '\0';
d.d_reclen = _DIRENT_SIZE(&d);
/* Stop reading if the directory entry we are treating is
* bigger than the amount of data that can be returned. */
if (d.d_reclen > uio->uio_resid) {
error = -1;
break;
}
/* Copy the new dirent structure into the output buffer and
* advance pointers. */
error = uiomove(&d, d.d_reclen, uio);
(*cntp)++;
de = TAILQ_NEXT(de, td_entries);
} while (error == 0 && uio->uio_resid > 0 && de != NULL);
/* Update the offset and cache. */
if (de == NULL) {
uio->uio_offset = TMPFS_DIRCOOKIE_EOF;
node->tn_spec.tn_dir.tn_readdir_lastn = 0;
node->tn_spec.tn_dir.tn_readdir_lastp = NULL;
} else {
node->tn_spec.tn_dir.tn_readdir_lastn = uio->uio_offset =
tmpfs_dircookie(de);
node->tn_spec.tn_dir.tn_readdir_lastp = de;
}
node->tn_status |= TMPFS_NODE_ACCESSED;
return error;
}
/* --------------------------------------------------------------------- */
/*
* Resizes the aobj associated to the regular file pointed to by vp to
* the size newsize. 'vp' must point to a vnode that represents a regular
* file. 'newsize' must be positive.
*
* If the file is extended, the appropriate kevent is raised. This does
* not rise a write event though because resizing is not the same as
* writing.
*
* Returns zero on success or an appropriate error code on failure.
*/
int
tmpfs_reg_resize(struct vnode *vp, off_t newsize)
{
int error;
size_t newpages, oldpages;
struct tmpfs_mount *tmp;
struct tmpfs_node *node;
off_t oldsize;
KASSERT(vp->v_type == VREG);
KASSERT(newsize >= 0);
node = VP_TO_TMPFS_NODE(vp);
tmp = VFS_TO_TMPFS(vp->v_mount);
/* Convert the old and new sizes to the number of pages needed to
* store them. It may happen that we do not need to do anything
* because the last allocated page can accommodate the change on
* its own. */
oldsize = node->tn_size;
oldpages = round_page(oldsize) / PAGE_SIZE;
KASSERT(oldpages == node->tn_spec.tn_reg.tn_aobj_pages);
newpages = round_page(newsize) / PAGE_SIZE;
if (newpages > oldpages &&
newpages - oldpages > TMPFS_PAGES_AVAIL(tmp)) {
error = ENOSPC;
goto out;
}
node->tn_spec.tn_reg.tn_aobj_pages = newpages;
tmp->tm_pages_used += (newpages - oldpages);
node->tn_size = newsize;
uvm_vnp_setsize(vp, newsize);
if (newsize < oldsize) {
int zerolen = MIN(round_page(newsize), node->tn_size) - newsize;
/*
* free "backing store"
*/
if (newpages < oldpages) {
struct uvm_object *uobj;
uobj = node->tn_spec.tn_reg.tn_aobj;
simple_lock(&uobj->vmobjlock);
uao_dropswap_range(uobj, newpages, oldpages);
simple_unlock(&uobj->vmobjlock);
}
/*
* zero out the truncated part of the last page.
*/
uvm_vnp_zerorange(vp, newsize, zerolen);
}
error = 0;
if (newsize > oldsize)
VN_KNOTE(vp, NOTE_EXTEND);
out:
return error;
}
/* --------------------------------------------------------------------- */
/*
* Returns information about the number of available memory pages,
* including physical and virtual ones.
*
* If 'total' is true, the value returned is the total amount of memory
* pages configured for the system (either in use or free).
* If it is FALSE, the value returned is the amount of free memory pages.
*
* Remember to remove TMPFS_PAGES_RESERVED from the returned value to avoid
* excessive memory usage.
*
*/
size_t
tmpfs_mem_info(bool total)
{
size_t size;
size = 0;
size += uvmexp.swpgavail;
if (!total) {
size -= uvmexp.swpgonly;
}
size += uvmexp.free;
size += uvmexp.filepages;
if (size > uvmexp.wired) {
size -= uvmexp.wired;
} else {
size = 0;
}
return size;
}
/* --------------------------------------------------------------------- */
/*
* Change flags of the given vnode.
* Caller should execute tmpfs_update on vp after a successful execution.
* The vnode must be locked on entry and remain locked on exit.
*/
int
tmpfs_chflags(struct vnode *vp, int flags, kauth_cred_t cred, struct lwp *l)
{
int error;
struct tmpfs_node *node;
KASSERT(VOP_ISLOCKED(vp));
node = VP_TO_TMPFS_NODE(vp);
/* Disallow this operation if the file system is mounted read-only. */
if (vp->v_mount->mnt_flag & MNT_RDONLY)
return EROFS;
/* XXX: The following comes from UFS code, and can be found in
* several other file systems. Shouldn't this be centralized
* somewhere? */
if (kauth_cred_geteuid(cred) != node->tn_uid &&
(error = kauth_authorize_generic(cred, KAUTH_GENERIC_ISSUSER,
NULL)))
return error;
if (kauth_authorize_generic(cred, KAUTH_GENERIC_ISSUSER, NULL) == 0) {
/* The super-user is only allowed to change flags if the file
* wasn't protected before and the securelevel is zero. */
if ((node->tn_flags & (SF_IMMUTABLE | SF_APPEND)) &&
kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_CHSYSFLAGS,
0, NULL, NULL, NULL))
return EPERM;
node->tn_flags = flags;
} else {
/* Regular users can change flags provided they only want to
* change user-specific ones, not those reserved for the
* super-user. */
if ((node->tn_flags & (SF_IMMUTABLE | SF_APPEND)) ||
(flags & UF_SETTABLE) != flags)
return EPERM;
if ((node->tn_flags & SF_SETTABLE) != (flags & SF_SETTABLE))
return EPERM;
node->tn_flags &= SF_SETTABLE;
node->tn_flags |= (flags & UF_SETTABLE);
}
node->tn_status |= TMPFS_NODE_CHANGED;
VN_KNOTE(vp, NOTE_ATTRIB);
KASSERT(VOP_ISLOCKED(vp));
return 0;
}
/* --------------------------------------------------------------------- */
/*
* Change access mode on the given vnode.
* Caller should execute tmpfs_update on vp after a successful execution.
* The vnode must be locked on entry and remain locked on exit.
*/
int
tmpfs_chmod(struct vnode *vp, mode_t mode, kauth_cred_t cred, struct lwp *l)
{
int error, ismember = 0;
struct tmpfs_node *node;
KASSERT(VOP_ISLOCKED(vp));
node = VP_TO_TMPFS_NODE(vp);
/* Disallow this operation if the file system is mounted read-only. */
if (vp->v_mount->mnt_flag & MNT_RDONLY)
return EROFS;
/* Immutable or append-only files cannot be modified, either. */
if (node->tn_flags & (IMMUTABLE | APPEND))
return EPERM;
/* XXX: The following comes from UFS code, and can be found in
* several other file systems. Shouldn't this be centralized
* somewhere? */
if (kauth_cred_geteuid(cred) != node->tn_uid &&
(error = kauth_authorize_generic(cred, KAUTH_GENERIC_ISSUSER,
NULL)))
return error;
if (kauth_authorize_generic(cred, KAUTH_GENERIC_ISSUSER, NULL) != 0) {
if (vp->v_type != VDIR && (mode & S_ISTXT))
return EFTYPE;
if ((kauth_cred_ismember_gid(cred, node->tn_gid,
&ismember) != 0 || !ismember) && (mode & S_ISGID))
return EPERM;
}
node->tn_mode = (mode & ALLPERMS);
node->tn_status |= TMPFS_NODE_CHANGED;
VN_KNOTE(vp, NOTE_ATTRIB);
KASSERT(VOP_ISLOCKED(vp));
return 0;
}
/* --------------------------------------------------------------------- */
/*
* Change ownership of the given vnode. At least one of uid or gid must
* be different than VNOVAL. If one is set to that value, the attribute
* is unchanged.
* Caller should execute tmpfs_update on vp after a successful execution.
* The vnode must be locked on entry and remain locked on exit.
*/
int
tmpfs_chown(struct vnode *vp, uid_t uid, gid_t gid, kauth_cred_t cred,
struct lwp *l)
{
int error, ismember = 0;
struct tmpfs_node *node;
KASSERT(VOP_ISLOCKED(vp));
node = VP_TO_TMPFS_NODE(vp);
/* Assign default values if they are unknown. */
KASSERT(uid != VNOVAL || gid != VNOVAL);
if (uid == VNOVAL)
uid = node->tn_uid;
if (gid == VNOVAL)
gid = node->tn_gid;
KASSERT(uid != VNOVAL && gid != VNOVAL);
/* Disallow this operation if the file system is mounted read-only. */
if (vp->v_mount->mnt_flag & MNT_RDONLY)
return EROFS;
/* Immutable or append-only files cannot be modified, either. */
if (node->tn_flags & (IMMUTABLE | APPEND))
return EPERM;
/* XXX: The following comes from UFS code, and can be found in
* several other file systems. Shouldn't this be centralized
* somewhere? */
if ((kauth_cred_geteuid(cred) != node->tn_uid || uid != node->tn_uid ||
(gid != node->tn_gid && !(kauth_cred_getegid(cred) == node->tn_gid ||
(kauth_cred_ismember_gid(cred, gid, &ismember) == 0 && ismember)))) &&
((error = kauth_authorize_generic(cred, KAUTH_GENERIC_ISSUSER,
NULL)) != 0))
return error;
node->tn_uid = uid;
node->tn_gid = gid;
node->tn_status |= TMPFS_NODE_CHANGED;
VN_KNOTE(vp, NOTE_ATTRIB);
KASSERT(VOP_ISLOCKED(vp));
return 0;
}
/* --------------------------------------------------------------------- */
/*
* Change size of the given vnode.
* Caller should execute tmpfs_update on vp after a successful execution.
* The vnode must be locked on entry and remain locked on exit.
*/
int
tmpfs_chsize(struct vnode *vp, u_quad_t size, kauth_cred_t cred,
struct lwp *l)
{
int error;
struct tmpfs_node *node;
KASSERT(VOP_ISLOCKED(vp));
node = VP_TO_TMPFS_NODE(vp);
/* Decide whether this is a valid operation based on the file type. */
error = 0;
switch (vp->v_type) {
case VDIR:
return EISDIR;
case VREG:
if (vp->v_mount->mnt_flag & MNT_RDONLY)
return EROFS;
break;
case VBLK:
/* FALLTHROUGH */
case VCHR:
/* FALLTHROUGH */
case VFIFO:
/* Allow modifications of special files even if in the file
* system is mounted read-only (we are not modifying the
* files themselves, but the objects they represent). */
return 0;
default:
/* Anything else is unsupported. */
return EOPNOTSUPP;
}
/* Immutable or append-only files cannot be modified, either. */
if (node->tn_flags & (IMMUTABLE | APPEND))
return EPERM;
error = tmpfs_truncate(vp, size);
/* tmpfs_truncate will raise the NOTE_EXTEND and NOTE_ATTRIB kevents
* for us, as will update tn_status; no need to do that here. */
KASSERT(VOP_ISLOCKED(vp));
return error;
}
/* --------------------------------------------------------------------- */
/*
* Change access and modification times of the given vnode.
* Caller should execute tmpfs_update on vp after a successful execution.
* The vnode must be locked on entry and remain locked on exit.
*/
int
tmpfs_chtimes(struct vnode *vp, struct timespec *atime, struct timespec *mtime,
int vaflags, kauth_cred_t cred, struct lwp *l)
{
int error;
struct tmpfs_node *node;
KASSERT(VOP_ISLOCKED(vp));
node = VP_TO_TMPFS_NODE(vp);
/* Disallow this operation if the file system is mounted read-only. */
if (vp->v_mount->mnt_flag & MNT_RDONLY)
return EROFS;
/* Immutable or append-only files cannot be modified, either. */
if (node->tn_flags & (IMMUTABLE | APPEND))
return EPERM;
/* XXX: The following comes from UFS code, and can be found in
* several other file systems. Shouldn't this be centralized
* somewhere? */
if (kauth_cred_geteuid(cred) != node->tn_uid &&
(error = kauth_authorize_generic(cred, KAUTH_GENERIC_ISSUSER,
NULL)) && ((vaflags & VA_UTIMES_NULL) == 0 ||
(error = VOP_ACCESS(vp, VWRITE, cred, l))))
return error;
if (atime->tv_sec != VNOVAL && atime->tv_nsec != VNOVAL)
node->tn_status |= TMPFS_NODE_ACCESSED;
if (mtime->tv_sec != VNOVAL && mtime->tv_nsec != VNOVAL)
node->tn_status |= TMPFS_NODE_MODIFIED;
tmpfs_update(vp, atime, mtime, 0);
VN_KNOTE(vp, NOTE_ATTRIB);
KASSERT(VOP_ISLOCKED(vp));
return 0;
}
/* --------------------------------------------------------------------- */
/* Sync timestamps */
void
tmpfs_itimes(struct vnode *vp, const struct timespec *acc,
const struct timespec *mod)
{
struct timespec now;
struct tmpfs_node *node;
node = VP_TO_TMPFS_NODE(vp);
if ((node->tn_status & (TMPFS_NODE_ACCESSED | TMPFS_NODE_MODIFIED |
TMPFS_NODE_CHANGED)) == 0)
return;
getnanotime(&now);
if (node->tn_status & TMPFS_NODE_ACCESSED) {
if (acc == NULL)
acc = &now;
node->tn_atime = *acc;
}
if (node->tn_status & TMPFS_NODE_MODIFIED) {
if (mod == NULL)
mod = &now;
node->tn_mtime = *mod;
}
if (node->tn_status & TMPFS_NODE_CHANGED)
node->tn_ctime = now;
node->tn_status &=
~(TMPFS_NODE_ACCESSED | TMPFS_NODE_MODIFIED | TMPFS_NODE_CHANGED);
}
/* --------------------------------------------------------------------- */
void
tmpfs_update(struct vnode *vp, const struct timespec *acc,
const struct timespec *mod, int flags)
{
struct tmpfs_node *node;
KASSERT(VOP_ISLOCKED(vp));
node = VP_TO_TMPFS_NODE(vp);
#if 0
if (flags & UPDATE_CLOSE)
; /* XXX Need to do anything special? */
#endif
tmpfs_itimes(vp, acc, mod);
KASSERT(VOP_ISLOCKED(vp));
}
/* --------------------------------------------------------------------- */
int
tmpfs_truncate(struct vnode *vp, off_t length)
{
bool extended;
int error;
struct tmpfs_node *node;
node = VP_TO_TMPFS_NODE(vp);
extended = length > node->tn_size;
if (length < 0) {
error = EINVAL;
goto out;
}
if (node->tn_size == length) {
error = 0;
goto out;
}
error = tmpfs_reg_resize(vp, length);
if (error == 0)
node->tn_status |= TMPFS_NODE_CHANGED | TMPFS_NODE_MODIFIED;
out:
tmpfs_update(vp, NULL, NULL, 0);
return error;
}
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