/*
* This opens /dev/tty. Because multiple opens of /dev/tty only
* generate a single open to the actual tty, the file modes are
* locked to FREAD|FWRITE.
*/
static int
cttyopen(struct dev_open_args *ap)
{
struct proc *p = curproc;
struct vnode *ttyvp;
int error;
KKASSERT(p);
retry:
if ((ttyvp = cttyvp(p)) == NULL)
return (ENXIO);
if (ttyvp->v_flag & VCTTYISOPEN)
return (0);
/*
* Messy interlock, don't let the vnode go away while we try to
* lock it and check for race after we might have blocked.
*/
vhold(ttyvp);
vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY);
if (ttyvp != cttyvp(p) || (ttyvp->v_flag & VCTTYISOPEN)) {
kprintf("Warning: cttyopen: race avoided\n");
vn_unlock(ttyvp);
vdrop(ttyvp);
goto retry;
}
vsetflags(ttyvp, VCTTYISOPEN);
error = VOP_OPEN(ttyvp, FREAD|FWRITE, ap->a_cred, NULL);
if (error)
vclrflags(ttyvp, VCTTYISOPEN);
vn_unlock(ttyvp);
vdrop(ttyvp);
return(error);
}
/*
* This opens /dev/tty. Because multiple opens of /dev/tty only
* generate a single open to the actual tty, the file modes are
* locked to FREAD|FWRITE.
*/
static int
cttyopen(struct dev_open_args *ap)
{
struct proc *p = curproc;
struct vnode *ttyvp;
int error;
KKASSERT(p);
retry:
if ((ttyvp = cttyvp(p)) == NULL)
return (ENXIO);
if (ttyvp->v_flag & VCTTYISOPEN)
return (0);
/*
* Messy interlock, don't let the vnode go away while we try to
* lock it and check for race after we might have blocked.
*
* WARNING! The device open (devfs_spec_open()) temporarily
* releases the vnode lock on ttyvp when issuing the
* dev_dopen(), which means that the VCTTYISOPEn flag
* can race during the VOP_OPEN().
*
* If something does race we have to undo our potentially
* extra open.
*/
vhold(ttyvp);
vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY);
if (ttyvp != cttyvp(p) || (ttyvp->v_flag & VCTTYISOPEN)) {
kprintf("Warning: cttyopen: race-1 avoided\n");
vn_unlock(ttyvp);
vdrop(ttyvp);
goto retry;
}
error = VOP_OPEN(ttyvp, FREAD|FWRITE, ap->a_cred, NULL);
/*
* Race against ctty close or change. This case has been validated
* and occurs every so often during synth builds.
*/
if (ttyvp != cttyvp(p) || (ttyvp->v_flag & VCTTYISOPEN)) {
if (error == 0)
VOP_CLOSE(ttyvp, FREAD|FWRITE, NULL);
vn_unlock(ttyvp);
vdrop(ttyvp);
goto retry;
}
if (error == 0)
vsetflags(ttyvp, VCTTYISOPEN);
vn_unlock(ttyvp);
vdrop(ttyvp);
return(error);
}
/*ARGSUSED*/
int
cttyopen(dev_t dev, int flag, int mode, struct proc *p)
{
struct vnode *ttyvp = cttyvp(p);
int error;
if (ttyvp == NULL)
return (ENXIO);
vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, p);
#ifdef PARANOID
/*
* Since group is tty and mode is 620 on most terminal lines
* and since sessions protect terminals from processes outside
* your session, this check is probably no longer necessary.
* Since it inhibits setuid root programs that later switch
* to another user from accessing /dev/tty, we have decided
* to delete this test. (mckusick 5/93)
*/
error = VOP_ACCESS(ttyvp,
(flag&FREAD ? VREAD : 0) | (flag&FWRITE ? VWRITE : 0), p->p_ucred, p);
if (!error)
#endif /* PARANOID */
error = VOP_OPEN(ttyvp, flag, NOCRED, p);
VOP_UNLOCK(ttyvp, 0, p);
return (error);
}
static int
cttykqfilter(struct dev_kqfilter_args *ap)
{
cdev_t dev = ap->a_head.a_dev;
struct proc *p = curproc;
struct knote *kn = ap->a_kn;
struct vnode *ttyvp;
KKASSERT(p);
ttyvp = cttyvp(p);
if (ttyvp != NULL)
return (VOP_KQFILTER(ttyvp, kn));
ap->a_result = 0;
switch (kn->kn_filter) {
case EVFILT_READ:
kn->kn_fop = &cttyfiltops_read;
kn->kn_hook = (caddr_t)dev;
break;
case EVFILT_WRITE:
kn->kn_fop = &cttyfiltops_write;
kn->kn_hook = (caddr_t)dev;
break;
default:
ap->a_result = EOPNOTSUPP;
return (0);
}
return (0);
}
int
cttykqfilter(dev_t dev, struct knote *kn)
{
struct vnode *ttyvp = cttyvp(curproc);
if (ttyvp == NULL)
return (ENXIO);
return (VOP_KQFILTER(ttyvp, kn));
}
/*ARGSUSED*/
static int
cttypoll(dev_t dev, int events, struct lwp *l)
{
struct vnode *ttyvp = cttyvp(l->l_proc);
if (ttyvp == NULL)
return (seltrue(dev, events, l));
return (VOP_POLL(ttyvp, events));
}
/*ARGSUSED*/
int
cttypoll(dev_t dev, int events, struct proc *p)
{
struct vnode *ttyvp = cttyvp(p);
if (ttyvp == NULL) /* try operation to get EOF/failure */
return (seltrue(dev, events, p));
return (VOP_POLL(ttyvp, events, p));
}
static int
cttykqfilter(dev_t dev, struct knote *kn)
{
/* This is called from filt_fileattach() by the attaching process. */
struct proc *p = curproc;
struct vnode *ttyvp = cttyvp(p);
if (ttyvp == NULL)
return (1);
return (VOP_KQFILTER(ttyvp, kn));
}
/*
* This closes /dev/tty. Because multiple opens of /dev/tty only
* generate a single open to the actual tty, the file modes are
* locked to FREAD|FWRITE.
*/
static int
cttyclose(struct dev_close_args *ap)
{
struct proc *p = curproc;
struct vnode *ttyvp;
int error;
KKASSERT(p);
retry:
/*
* The tty may have been TIOCNOTTY'd, don't return an
* error on close. We just have nothing to do.
*/
if ((ttyvp = cttyvp(p)) == NULL)
return(0);
if (ttyvp->v_flag & VCTTYISOPEN) {
/*
* Avoid a nasty race if we block while getting the lock.
*/
vref(ttyvp);
error = vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY |
LK_FAILRECLAIM);
if (error) {
vrele(ttyvp);
goto retry;
}
if (ttyvp != cttyvp(p) || (ttyvp->v_flag & VCTTYISOPEN) == 0) {
kprintf("Warning: cttyclose: race avoided\n");
vn_unlock(ttyvp);
vrele(ttyvp);
goto retry;
}
vclrflags(ttyvp, VCTTYISOPEN);
error = VOP_CLOSE(ttyvp, FREAD|FWRITE);
vn_unlock(ttyvp);
vrele(ttyvp);
} else {
error = 0;
}
return(error);
}
int
cttyopen(dev_t dev, int flag, int mode, struct proc *p)
{
struct vnode *ttyvp = cttyvp(p);
int error;
if (ttyvp == NULL)
return (ENXIO);
vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, p);
error = VOP_OPEN(ttyvp, flag, NOCRED);
VOP_UNLOCK(ttyvp, 0);
return (error);
}
/*ARGSUSED*/
static int
cttywrite(dev_t dev, struct uio *uio, int flag)
{
struct vnode *ttyvp = cttyvp(curproc);
int error;
if (ttyvp == NULL)
return (EIO);
vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY);
error = VOP_WRITE(ttyvp, uio, flag, NOCRED);
VOP_UNLOCK(ttyvp);
return (error);
}
/*ARGSUSED*/
int
cttywrite(dev_t dev, struct uio *uio, int flag)
{
struct proc *p = uio->uio_procp;
struct vnode *ttyvp = cttyvp(uio->uio_procp);
int error;
if (ttyvp == NULL)
return (EIO);
vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, p);
error = VOP_WRITE(ttyvp, uio, flag, NOCRED);
VOP_UNLOCK(ttyvp, 0, p);
return (error);
}
int
cttyselect(__unused dev_t dev, int flag, void* wql, __unused proc_t p)
{
vnode_t ttyvp = cttyvp(current_proc());
struct vfs_context context;
int error;
context.vc_thread = current_thread();
context.vc_ucred = NOCRED;
if (ttyvp == NULL)
return (1); /* try operation to get EOF/failure */
error = VNOP_SELECT(ttyvp, flag, FREAD|FWRITE, wql, &context);
vnode_put(ttyvp);
return (error);
}
/*
* Read from the controlling terminal (/dev/tty). The tty is refed as
* of the cttyvp(), but the ref can get ripped out from under us if
* the controlling terminal is revoked while we are blocked on the lock,
* so use vget() instead of vn_lock().
*/
static int
cttywrite(struct dev_write_args *ap)
{
struct proc *p = curproc;
struct vnode *ttyvp;
int error;
KKASSERT(p);
ttyvp = cttyvp(p);
if (ttyvp == NULL)
return (EIO);
if ((error = vget(ttyvp, LK_EXCLUSIVE | LK_RETRY)) == 0) {
error = VOP_WRITE(ttyvp, ap->a_uio, ap->a_ioflag, NOCRED);
vput(ttyvp);
}
return (error);
}
int
cttywrite(__unused dev_t dev, struct uio *uio, int flag)
{
vnode_t ttyvp = cttyvp(current_proc());
struct vfs_context context;
int error;
if (ttyvp == NULL)
return (EIO);
context.vc_thread = current_thread();
context.vc_ucred = NOCRED;
error = VNOP_WRITE(ttyvp, uio, flag, &context);
vnode_put(ttyvp);
return (error);
}
/*ARGSUSED*/
int
cttyioctl(dev_t dev, u_long cmd, caddr_t addr, int flag, struct proc *p)
{
struct vnode *ttyvp = cttyvp(p);
if (ttyvp == NULL)
return (EIO);
if (cmd == TIOCSCTTY) /* XXX */
return (EINVAL);
if (cmd == TIOCNOTTY) {
if (!SESS_LEADER(p)) {
atomic_clearbits_int(&p->p_flag, P_CONTROLT);
return (0);
} else
return (EINVAL);
}
return (VOP_IOCTL(ttyvp, cmd, addr, flag, NOCRED, p));
}
int
cttyopen(__unused dev_t dev, int flag, __unused int mode, proc_t p)
{
vnode_t ttyvp = cttyvp(p);
struct vfs_context context;
int error;
if (ttyvp == NULL)
return (ENXIO);
context.vc_thread = current_thread();
context.vc_ucred = kauth_cred_proc_ref(p);
error = VNOP_OPEN(ttyvp, flag, &context);
vnode_put(ttyvp);
kauth_cred_unref(&context.vc_ucred);
return (error);
}
/*ARGSUSED*/
static int
cttyioctl(struct dev_ioctl_args *ap)
{
struct vnode *ttyvp;
struct proc *p = curproc;
KKASSERT(p);
lwkt_gettoken(&p->p_token);
lwkt_gettoken(&proc_token);
ttyvp = cttyvp(p);
if (ttyvp == NULL) {
lwkt_reltoken(&proc_token);
lwkt_reltoken(&p->p_token);
return (EIO);
}
/*
* Don't allow controlling tty to be set to the controlling tty
* (infinite recursion).
*/
if (ap->a_cmd == TIOCSCTTY) {
lwkt_reltoken(&proc_token);
lwkt_reltoken(&p->p_token);
return EINVAL;
}
if (ap->a_cmd == TIOCNOTTY) {
if (!SESS_LEADER(p)) {
p->p_flags &= ~P_CONTROLT;
lwkt_reltoken(&proc_token);
lwkt_reltoken(&p->p_token);
return (0);
} else {
lwkt_reltoken(&proc_token);
lwkt_reltoken(&p->p_token);
return (EINVAL);
}
}
lwkt_reltoken(&proc_token);
lwkt_reltoken(&p->p_token);
return (VOP_IOCTL(ttyvp, ap->a_cmd, ap->a_data, ap->a_fflag,
ap->a_cred, ap->a_sysmsg));
}
/*ARGSUSED*/
static int
cttyioctl(dev_t dev, u_long cmd, void *addr, int flag, struct lwp *l)
{
struct vnode *ttyvp = cttyvp(l->l_proc);
int rv;
if (ttyvp == NULL)
return (EIO);
if (cmd == TIOCSCTTY) /* XXX */
return (EINVAL);
if (cmd == TIOCNOTTY) {
mutex_enter(proc_lock);
if (!SESS_LEADER(l->l_proc)) {
l->l_proc->p_lflag &= ~PL_CONTROLT;
rv = 0;
} else
rv = EINVAL;
mutex_exit(proc_lock);
return (rv);
}
return (VOP_IOCTL(ttyvp, cmd, addr, flag, NOCRED));
}
int
cttyioctl(__unused dev_t dev, u_long cmd, caddr_t addr, int flag, proc_t p)
{
vnode_t ttyvp = cttyvp(current_proc());
struct vfs_context context;
struct session *sessp;
int error = 0;
if (ttyvp == NULL)
return (EIO);
if (cmd == TIOCSCTTY) { /* don't allow controlling tty to be set */
error = EINVAL; /* to controlling tty -- infinite recursion */
goto out;
}
if (cmd == TIOCNOTTY) {
sessp = proc_session(p);
if (!SESS_LEADER(p, sessp)) {
OSBitAndAtomic(~((uint32_t)P_CONTROLT), &p->p_flag);
if (sessp != SESSION_NULL)
session_rele(sessp);
error = 0;
goto out;
} else {
if (sessp != SESSION_NULL)
session_rele(sessp);
error = EINVAL;
goto out;
}
}
context.vc_thread = current_thread();
context.vc_ucred = NOCRED;
error = VNOP_IOCTL(ttyvp, cmd, addr, flag, &context);
out:
vnode_put(ttyvp);
return (error);
}
int
cttyopen(dev_t dev, int flag, __unused int mode, proc_t p)
{
vnode_t ttyvp = cttyvp(p);
struct vfs_context context;
int error = 0;
int cttyflag, doclose = 0;
struct session *sessp;
if (ttyvp == NULL)
return (ENXIO);
context.vc_thread = current_thread();
context.vc_ucred = kauth_cred_proc_ref(p);
sessp = proc_session(p);
session_lock(sessp);
cttyflag = sessp->s_flags & S_CTTYREF;
session_unlock(sessp);
/*
* A little hack--this device, used by many processes,
* happens to do an open on another device, which can
* cause unhappiness if the second-level open blocks indefinitely
* (as could be the case if the master side has hung up). Since
* we know that this driver doesn't care about the serializing
* opens and closes, we can drop the lock. To avoid opencount leak,
* open the vnode only for the first time.
*/
if (cttyflag == 0) {
devsw_unlock(dev, S_IFCHR);
error = VNOP_OPEN(ttyvp, flag, &context);
devsw_lock(dev, S_IFCHR);
if (error)
goto out;
/*
* If S_CTTYREF is set, some other thread did an open
* and was able to set the flag, now perform a close, else
* set the flag.
*/
session_lock(sessp);
if (cttyflag == (sessp->s_flags & S_CTTYREF))
sessp->s_flags |= S_CTTYREF;
else
doclose = 1;
session_unlock(sessp);
/*
* We have to take a reference here to make sure a close
* gets called during revoke. Note that once a controlling
* tty gets opened by this driver, the only way close will
* get called is when the session leader , whose controlling
* tty is ttyvp, exits and vnode is revoked. We cannot
* redirect close from this driver because underlying controlling
* terminal might change and close may get redirected to a
* wrong vnode causing panic.
*/
if (doclose) {
devsw_unlock(dev, S_IFCHR);
VNOP_CLOSE(ttyvp, flag, &context);
devsw_lock(dev, S_IFCHR);
} else {
error = vnode_ref(ttyvp);
}
}
out:
session_rele(sessp);
vnode_put(ttyvp);
kauth_cred_unref(&context.vc_ucred);
return (error);
}
