NetBSD-5.0.2/sys/fs/ptyfs/ptyfs_subr.c
/* $NetBSD: ptyfs_subr.c,v 1.16 2008/05/05 17:11:16 ad Exp $ */
/*
* Copyright (c) 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed 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. 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.
*
* @(#)ptyfs_subr.c 8.6 (Berkeley) 5/14/95
*/
/*
* Copyright (c) 1994 Christopher G. Demetriou. All rights reserved.
* Copyright (c) 1993 Jan-Simon Pendry
*
* This code is derived from software contributed 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.
*
* @(#)procfs_subr.c 8.6 (Berkeley) 5/14/95
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: ptyfs_subr.c,v 1.16 2008/05/05 17:11:16 ad Exp $");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/time.h>
#include <sys/kernel.h>
#include <sys/vnode.h>
#include <sys/stat.h>
#include <sys/malloc.h>
#include <sys/file.h>
#include <sys/namei.h>
#include <sys/filedesc.h>
#include <sys/select.h>
#include <sys/tty.h>
#include <sys/pty.h>
#include <sys/kauth.h>
#include <sys/lwp.h>
#include <fs/ptyfs/ptyfs.h>
#include <miscfs/specfs/specdev.h>
static kmutex_t ptyfs_hashlock;
static LIST_HEAD(ptyfs_hashhead, ptyfsnode) *ptyfs_used_tbl, *ptyfs_free_tbl;
static u_long ptyfs_used_mask, ptyfs_free_mask; /* size of hash table - 1 */
static kmutex_t ptyfs_used_slock, ptyfs_free_slock;
static void ptyfs_getinfo(struct ptyfsnode *, struct lwp *);
static void ptyfs_hashins(struct ptyfsnode *);
static void ptyfs_hashrem(struct ptyfsnode *);
static struct vnode *ptyfs_used_get(ptyfstype, int, struct mount *, int);
static struct ptyfsnode *ptyfs_free_get(ptyfstype, int, struct lwp *);
static void ptyfs_rehash(kmutex_t *, struct ptyfs_hashhead **,
u_long *);
#define PTYHASH(type, pty, mask) (PTYFS_FILENO(type, pty) % (mask + 1))
static void
ptyfs_getinfo(struct ptyfsnode *ptyfs, struct lwp *l)
{
extern struct ptm_pty *ptyfs_save_ptm, ptm_ptyfspty;
if (ptyfs->ptyfs_type == PTYFSroot) {
ptyfs->ptyfs_mode = S_IRUSR|S_IXUSR|S_IRGRP|S_IXGRP|
S_IROTH|S_IXOTH;
goto out;
} else
ptyfs->ptyfs_mode = S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|
S_IROTH|S_IWOTH;
if (ptyfs_save_ptm != NULL && ptyfs_save_ptm != &ptm_ptyfspty) {
int error;
struct nameidata nd;
char ttyname[64];
kauth_cred_t cred;
struct vattr va;
/*
* We support traditional ptys, so we copy the info
* from the inode
*/
if ((error = (*ptyfs_save_ptm->makename)(
ptyfs_save_ptm, l, ttyname, sizeof(ttyname),
ptyfs->ptyfs_pty, ptyfs->ptyfs_type == PTYFSpts ? 't'
: 'p')) != 0)
goto out;
NDINIT(&nd, LOOKUP, NOFOLLOW|LOCKLEAF, UIO_SYSSPACE, ttyname);
if ((error = namei(&nd)) != 0)
goto out;
cred = kauth_cred_alloc();
error = VOP_GETATTR(nd.ni_vp, &va, cred);
kauth_cred_free(cred);
VOP_UNLOCK(nd.ni_vp, 0);
vrele(nd.ni_vp);
if (error)
goto out;
ptyfs->ptyfs_uid = va.va_uid;
ptyfs->ptyfs_gid = va.va_gid;
ptyfs->ptyfs_mode = va.va_mode;
ptyfs->ptyfs_flags = va.va_flags;
ptyfs->ptyfs_birthtime = va.va_birthtime;
ptyfs->ptyfs_ctime = va.va_ctime;
ptyfs->ptyfs_mtime = va.va_mtime;
ptyfs->ptyfs_atime = va.va_atime;
return;
}
out:
ptyfs->ptyfs_uid = ptyfs->ptyfs_gid = 0;
ptyfs->ptyfs_flags |= PTYFS_CHANGE;
PTYFS_ITIMES(ptyfs, NULL, NULL, NULL);
ptyfs->ptyfs_birthtime = ptyfs->ptyfs_mtime =
ptyfs->ptyfs_atime = ptyfs->ptyfs_ctime;
ptyfs->ptyfs_flags = 0;
}
/*
* allocate a ptyfsnode/vnode pair. the vnode is
* referenced, and locked.
*
* the pid, ptyfs_type, and mount point uniquely
* identify a ptyfsnode. the mount point is needed
* because someone might mount this filesystem
* twice.
*
* all ptyfsnodes are maintained on a singly-linked
* list. new nodes are only allocated when they cannot
* be found on this list. entries on the list are
* removed when the vfs reclaim entry is called.
*
* a single lock is kept for the entire list. this is
* needed because the getnewvnode() function can block
* waiting for a vnode to become free, in which case there
* may be more than one ptyess trying to get the same
* vnode. this lock is only taken if we are going to
* call getnewvnode, since the kernel itself is single-threaded.
*
* if an entry is found on the list, then call vget() to
* take a reference. this is done because there may be
* zero references to it and so it needs to removed from
* the vnode free list.
*/
int
ptyfs_allocvp(struct mount *mp, struct vnode **vpp, ptyfstype type, int pty,
struct lwp *l)
{
struct ptyfsnode *ptyfs;
struct vnode *vp;
int error;
retry:
if ((*vpp = ptyfs_used_get(type, pty, mp, LK_EXCLUSIVE)) != NULL)
return 0;
if ((error = getnewvnode(VT_PTYFS, mp, ptyfs_vnodeop_p, &vp)) != 0) {
*vpp = NULL;
return error;
}
mutex_enter(&ptyfs_hashlock);
if (ptyfs_used_get(type, pty, mp, 0) != NULL) {
mutex_exit(&ptyfs_hashlock);
ungetnewvnode(vp);
goto retry;
}
vp->v_data = ptyfs = ptyfs_free_get(type, pty, l);
ptyfs->ptyfs_vnode = vp;
switch (type) {
case PTYFSroot: /* /pts = dr-xr-xr-x */
vp->v_type = VDIR;
vp->v_vflag = VV_ROOT;
break;
case PTYFSpts: /* /pts/N = cxxxxxxxxx */
case PTYFSptc: /* controlling side = cxxxxxxxxx */
vp->v_type = VCHR;
spec_node_init(vp, PTYFS_MAKEDEV(ptyfs));
break;
default:
panic("ptyfs_allocvp");
}
ptyfs_hashins(ptyfs);
uvm_vnp_setsize(vp, 0);
mutex_exit(&ptyfs_hashlock);
*vpp = vp;
return 0;
}
int
ptyfs_freevp(struct vnode *vp)
{
struct ptyfsnode *ptyfs = VTOPTYFS(vp);
ptyfs_hashrem(ptyfs);
vp->v_data = NULL;
return 0;
}
/*
* Initialize ptyfsnode hash table.
*/
void
ptyfs_hashinit(void)
{
ptyfs_used_tbl = hashinit(desiredvnodes / 4, HASH_LIST, true,
&ptyfs_used_mask);
ptyfs_free_tbl = hashinit(desiredvnodes / 4, HASH_LIST, true,
&ptyfs_free_mask);
mutex_init(&ptyfs_hashlock, MUTEX_DEFAULT, IPL_NONE);
mutex_init(&ptyfs_used_slock, MUTEX_DEFAULT, IPL_NONE);
mutex_init(&ptyfs_free_slock, MUTEX_DEFAULT, IPL_NONE);
}
void
ptyfs_hashreinit(void)
{
ptyfs_rehash(&ptyfs_used_slock, &ptyfs_used_tbl, &ptyfs_used_mask);
ptyfs_rehash(&ptyfs_free_slock, &ptyfs_free_tbl, &ptyfs_free_mask);
}
static void
ptyfs_rehash(kmutex_t *hlock, struct ptyfs_hashhead **hhead,
u_long *hmask)
{
struct ptyfsnode *pp;
struct ptyfs_hashhead *oldhash, *hash;
u_long i, oldmask, mask, val;
hash = hashinit(desiredvnodes / 4, HASH_LIST, true, &mask);
mutex_enter(hlock);
oldhash = *hhead;
oldmask = *hmask;
*hhead = hash;
*hmask = mask;
for (i = 0; i <= oldmask; i++) {
while ((pp = LIST_FIRST(&oldhash[i])) != NULL) {
LIST_REMOVE(pp, ptyfs_hash);
val = PTYHASH(pp->ptyfs_type, pp->ptyfs_pty,
ptyfs_used_mask);
LIST_INSERT_HEAD(&hash[val], pp, ptyfs_hash);
}
}
mutex_exit(hlock);
hashdone(oldhash, HASH_LIST, oldmask);
}
/*
* Free ptyfsnode hash table.
*/
void
ptyfs_hashdone(void)
{
hashdone(ptyfs_used_tbl, HASH_LIST, ptyfs_used_mask);
hashdone(ptyfs_free_tbl, HASH_LIST, ptyfs_free_mask);
}
/*
* Get a ptyfsnode from the free table, or allocate one.
* Removes the node from the free table.
*/
struct ptyfsnode *
ptyfs_free_get(ptyfstype type, int pty, struct lwp *l)
{
struct ptyfs_hashhead *ppp;
struct ptyfsnode *pp;
mutex_enter(&ptyfs_free_slock);
ppp = &ptyfs_free_tbl[PTYHASH(type, pty, ptyfs_free_mask)];
LIST_FOREACH(pp, ppp, ptyfs_hash) {
if (pty == pp->ptyfs_pty && pp->ptyfs_type == type) {
LIST_REMOVE(pp, ptyfs_hash);
mutex_exit(&ptyfs_free_slock);
return pp;
}
}
mutex_exit(&ptyfs_free_slock);
MALLOC(pp, void *, sizeof(struct ptyfsnode), M_TEMP, M_WAITOK);
pp->ptyfs_pty = pty;
pp->ptyfs_type = type;
pp->ptyfs_fileno = PTYFS_FILENO(pty, type);
ptyfs_getinfo(pp, l);
return pp;
}
struct vnode *
ptyfs_used_get(ptyfstype type, int pty, struct mount *mp, int flags)
{
struct ptyfs_hashhead *ppp;
struct ptyfsnode *pp;
struct vnode *vp;
loop:
mutex_enter(&ptyfs_used_slock);
ppp = &ptyfs_used_tbl[PTYHASH(type, pty, ptyfs_used_mask)];
LIST_FOREACH(pp, ppp, ptyfs_hash) {
vp = PTYFSTOV(pp);
if (pty == pp->ptyfs_pty && pp->ptyfs_type == type &&
vp->v_mount == mp) {
if (flags == 0) {
mutex_exit(&ptyfs_used_slock);
} else {
mutex_enter(&vp->v_interlock);
mutex_exit(&ptyfs_used_slock);
if (vget(vp, flags | LK_INTERLOCK))
goto loop;
}
return vp;
}
}
mutex_exit(&ptyfs_used_slock);
return NULL;
}
/*
* Insert the ptyfsnode into the used table and lock it.
*/
static void
ptyfs_hashins(struct ptyfsnode *pp)
{
struct ptyfs_hashhead *ppp;
/* lock the ptyfsnode, then put it on the appropriate hash list */
vlockmgr(&pp->ptyfs_vnode->v_lock, LK_EXCLUSIVE);
mutex_enter(&ptyfs_used_slock);
ppp = &ptyfs_used_tbl[PTYHASH(pp->ptyfs_type, pp->ptyfs_pty,
ptyfs_used_mask)];
LIST_INSERT_HEAD(ppp, pp, ptyfs_hash);
mutex_exit(&ptyfs_used_slock);
}
/*
* Remove the ptyfsnode from the used table, and add it to the free table
*/
static void
ptyfs_hashrem(struct ptyfsnode *pp)
{
struct ptyfs_hashhead *ppp;
mutex_enter(&ptyfs_used_slock);
LIST_REMOVE(pp, ptyfs_hash);
mutex_exit(&ptyfs_used_slock);
mutex_enter(&ptyfs_free_slock);
ppp = &ptyfs_free_tbl[PTYHASH(pp->ptyfs_type, pp->ptyfs_pty,
ptyfs_free_mask)];
LIST_INSERT_HEAD(ppp, pp, ptyfs_hash);
mutex_exit(&ptyfs_free_slock);
}