/*
* Exit: deallocate address space and other resources, change proc state to
* zombie, and unlink proc from allproc and parent's lists. Save exit status
* and rusage for wait(). Check for child processes and orphan them.
*/
void
exit1(struct thread *td, int rv)
{
struct proc *p, *nq, *q;
struct vnode *vtmp;
struct vnode *ttyvp = NULL;
#ifdef KTRACE
struct vnode *tracevp;
struct ucred *tracecred;
#endif
struct plimit *plim;
int locked;
mtx_assert(&Giant, MA_NOTOWNED);
p = td->td_proc;
/*
* XXX in case we're rebooting we just let init die in order to
* work around an unsolved stack overflow seen very late during
* shutdown on sparc64 when the gmirror worker process exists.
*/
if (p == initproc && rebooting == 0) {
printf("init died (signal %d, exit %d)\n",
WTERMSIG(rv), WEXITSTATUS(rv));
panic("Going nowhere without my init!");
}
/*
* MUST abort all other threads before proceeding past here.
*/
PROC_LOCK(p);
while (p->p_flag & P_HADTHREADS) {
/*
* First check if some other thread got here before us..
* if so, act apropriatly, (exit or suspend);
*/
thread_suspend_check(0);
/*
* Kill off the other threads. This requires
* some co-operation from other parts of the kernel
* so it may not be instantaneous. With this state set
* any thread entering the kernel from userspace will
* thread_exit() in trap(). Any thread attempting to
* sleep will return immediately with EINTR or EWOULDBLOCK
* which will hopefully force them to back out to userland
* freeing resources as they go. Any thread attempting
* to return to userland will thread_exit() from userret().
* thread_exit() will unsuspend us when the last of the
* other threads exits.
* If there is already a thread singler after resumption,
* calling thread_single will fail; in that case, we just
* re-check all suspension request, the thread should
* either be suspended there or exit.
*/
if (! thread_single(SINGLE_EXIT))
break;
/*
* All other activity in this process is now stopped.
* Threading support has been turned off.
*/
}
KASSERT(p->p_numthreads == 1,
("exit1: proc %p exiting with %d threads", p, p->p_numthreads));
/*
* Wakeup anyone in procfs' PIOCWAIT. They should have a hold
* on our vmspace, so we should block below until they have
* released their reference to us. Note that if they have
* requested S_EXIT stops we will block here until they ack
* via PIOCCONT.
*/
_STOPEVENT(p, S_EXIT, rv);
/*
* Note that we are exiting and do another wakeup of anyone in
* PIOCWAIT in case they aren't listening for S_EXIT stops or
* decided to wait again after we told them we are exiting.
*/
p->p_flag |= P_WEXIT;
wakeup(&p->p_stype);
/*
* Wait for any processes that have a hold on our vmspace to
* release their reference.
*/
while (p->p_lock > 0)
msleep(&p->p_lock, &p->p_mtx, PWAIT, "exithold", 0);
PROC_UNLOCK(p);
/* Drain the limit callout while we don't have the proc locked */
callout_drain(&p->p_limco);
#ifdef AUDIT
/*
* The Sun BSM exit token contains two components: an exit status as
* passed to exit(), and a return value to indicate what sort of exit
* it was. The exit status is WEXITSTATUS(rv), but it's not clear
* what the return value is.
*/
AUDIT_ARG_EXIT(WEXITSTATUS(rv), 0);
AUDIT_SYSCALL_EXIT(0, td);
#endif
/* Are we a task leader? */
if (p == p->p_leader) {
mtx_lock(&ppeers_lock);
q = p->p_peers;
while (q != NULL) {
PROC_LOCK(q);
psignal(q, SIGKILL);
PROC_UNLOCK(q);
q = q->p_peers;
}
while (p->p_peers != NULL)
msleep(p, &ppeers_lock, PWAIT, "exit1", 0);
mtx_unlock(&ppeers_lock);
}
/*
* Check if any loadable modules need anything done at process exit.
* E.g. SYSV IPC stuff
* XXX what if one of these generates an error?
*/
EVENTHANDLER_INVOKE(process_exit, p);
/*
* If parent is waiting for us to exit or exec,
* P_PPWAIT is set; we will wakeup the parent below.
*/
PROC_LOCK(p);
stopprofclock(p);
p->p_flag &= ~(P_TRACED | P_PPWAIT);
/*
* Stop the real interval timer. If the handler is currently
* executing, prevent it from rearming itself and let it finish.
*/
if (timevalisset(&p->p_realtimer.it_value) &&
callout_stop(&p->p_itcallout) == 0) {
timevalclear(&p->p_realtimer.it_interval);
msleep(&p->p_itcallout, &p->p_mtx, PWAIT, "ritwait", 0);
KASSERT(!timevalisset(&p->p_realtimer.it_value),
("realtime timer is still armed"));
}
PROC_UNLOCK(p);
/*
* Reset any sigio structures pointing to us as a result of
* F_SETOWN with our pid.
*/
funsetownlst(&p->p_sigiolst);
/*
* If this process has an nlminfo data area (for lockd), release it
*/
if (nlminfo_release_p != NULL && p->p_nlminfo != NULL)
(*nlminfo_release_p)(p);
/*
* Close open files and release open-file table.
* This may block!
*/
fdfree(td);
/*
* If this thread tickled GEOM, we need to wait for the giggling to
* stop before we return to userland
*/
if (td->td_pflags & TDP_GEOM)
g_waitidle();
/*
* Remove ourself from our leader's peer list and wake our leader.
*/
mtx_lock(&ppeers_lock);
if (p->p_leader->p_peers) {
q = p->p_leader;
while (q->p_peers != p)
q = q->p_peers;
q->p_peers = p->p_peers;
wakeup(p->p_leader);
}
mtx_unlock(&ppeers_lock);
vmspace_exit(td);
sx_xlock(&proctree_lock);
if (SESS_LEADER(p)) {
struct session *sp = p->p_session;
struct tty *tp;
/*
* s_ttyp is not zero'd; we use this to indicate that
* the session once had a controlling terminal. (for
* logging and informational purposes)
*/
SESS_LOCK(sp);
ttyvp = sp->s_ttyvp;
tp = sp->s_ttyp;
sp->s_ttyvp = NULL;
sp->s_leader = NULL;
SESS_UNLOCK(sp);
/*
* Signal foreground pgrp and revoke access to
* controlling terminal if it has not been revoked
* already.
*
* Because the TTY may have been revoked in the mean
* time and could already have a new session associated
* with it, make sure we don't send a SIGHUP to a
* foreground process group that does not belong to this
* session.
*/
if (tp != NULL) {
tty_lock(tp);
if (tp->t_session == sp)
tty_signal_pgrp(tp, SIGHUP);
tty_unlock(tp);
}
if (ttyvp != NULL) {
sx_xunlock(&proctree_lock);
if (vn_lock(ttyvp, LK_EXCLUSIVE) == 0) {
VOP_REVOKE(ttyvp, REVOKEALL);
VOP_UNLOCK(ttyvp, 0);
}
sx_xlock(&proctree_lock);
}
}
fixjobc(p, p->p_pgrp, 0);
sx_xunlock(&proctree_lock);
(void)acct_process(td);
/* Release the TTY now we've unlocked everything. */
if (ttyvp != NULL)
vrele(ttyvp);
#ifdef KTRACE
/*
* Disable tracing, then drain any pending records and release
* the trace file.
*/
if (p->p_traceflag != 0) {
PROC_LOCK(p);
mtx_lock(&ktrace_mtx);
p->p_traceflag = 0;
mtx_unlock(&ktrace_mtx);
PROC_UNLOCK(p);
ktrprocexit(td);
PROC_LOCK(p);
mtx_lock(&ktrace_mtx);
tracevp = p->p_tracevp;
p->p_tracevp = NULL;
tracecred = p->p_tracecred;
p->p_tracecred = NULL;
mtx_unlock(&ktrace_mtx);
PROC_UNLOCK(p);
if (tracevp != NULL) {
locked = VFS_LOCK_GIANT(tracevp->v_mount);
vrele(tracevp);
VFS_UNLOCK_GIANT(locked);
}
if (tracecred != NULL)
crfree(tracecred);
}
#endif
/*
* Release reference to text vnode
*/
if ((vtmp = p->p_textvp) != NULL) {
p->p_textvp = NULL;
locked = VFS_LOCK_GIANT(vtmp->v_mount);
vrele(vtmp);
VFS_UNLOCK_GIANT(locked);
}
/*
* Release our limits structure.
*/
PROC_LOCK(p);
plim = p->p_limit;
p->p_limit = NULL;
PROC_UNLOCK(p);
lim_free(plim);
/*
* Remove proc from allproc queue and pidhash chain.
* Place onto zombproc. Unlink from parent's child list.
*/
sx_xlock(&allproc_lock);
LIST_REMOVE(p, p_list);
LIST_INSERT_HEAD(&zombproc, p, p_list);
LIST_REMOVE(p, p_hash);
sx_xunlock(&allproc_lock);
/*
* Call machine-dependent code to release any
* machine-dependent resources other than the address space.
* The address space is released by "vmspace_exitfree(p)" in
* vm_waitproc().
*/
cpu_exit(td);
WITNESS_WARN(WARN_PANIC, NULL, "process (pid %d) exiting", p->p_pid);
/*
* Reparent all of our children to init.
*/
sx_xlock(&proctree_lock);
q = LIST_FIRST(&p->p_children);
if (q != NULL) /* only need this if any child is S_ZOMB */
wakeup(initproc);
for (; q != NULL; q = nq) {
nq = LIST_NEXT(q, p_sibling);
PROC_LOCK(q);
proc_reparent(q, initproc);
q->p_sigparent = SIGCHLD;
/*
* Traced processes are killed
* since their existence means someone is screwing up.
*/
if (q->p_flag & P_TRACED) {
struct thread *temp;
q->p_flag &= ~(P_TRACED | P_STOPPED_TRACE);
FOREACH_THREAD_IN_PROC(q, temp)
temp->td_dbgflags &= ~TDB_SUSPEND;
psignal(q, SIGKILL);
}
PROC_UNLOCK(q);
}
/* Save exit status. */
PROC_LOCK(p);
p->p_xstat = rv;
p->p_xthread = td;
/* Tell the prison that we are gone. */
prison_proc_free(p->p_ucred->cr_prison);
#ifdef KDTRACE_HOOKS
/*
* Tell the DTrace fasttrap provider about the exit if it
* has declared an interest.
*/
if (dtrace_fasttrap_exit)
dtrace_fasttrap_exit(p);
#endif
/*
* Notify interested parties of our demise.
*/
KNOTE_LOCKED(&p->p_klist, NOTE_EXIT);
#ifdef KDTRACE_HOOKS
int reason = CLD_EXITED;
if (WCOREDUMP(rv))
reason = CLD_DUMPED;
else if (WIFSIGNALED(rv))
reason = CLD_KILLED;
SDT_PROBE(proc, kernel, , exit, reason, 0, 0, 0, 0);
#endif
/*
* Just delete all entries in the p_klist. At this point we won't
* report any more events, and there are nasty race conditions that
* can beat us if we don't.
*/
knlist_clear(&p->p_klist, 1);
/*
* Notify parent that we're gone. If parent has the PS_NOCLDWAIT
* flag set, or if the handler is set to SIG_IGN, notify process
* 1 instead (and hope it will handle this situation).
*/
PROC_LOCK(p->p_pptr);
mtx_lock(&p->p_pptr->p_sigacts->ps_mtx);
if (p->p_pptr->p_sigacts->ps_flag & (PS_NOCLDWAIT | PS_CLDSIGIGN)) {
struct proc *pp;
mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx);
pp = p->p_pptr;
PROC_UNLOCK(pp);
proc_reparent(p, initproc);
p->p_sigparent = SIGCHLD;
PROC_LOCK(p->p_pptr);
/*
* Notify parent, so in case he was wait(2)ing or
* executing waitpid(2) with our pid, he will
* continue.
*/
wakeup(pp);
} else
mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx);
if (p->p_pptr == initproc)
psignal(p->p_pptr, SIGCHLD);
else if (p->p_sigparent != 0) {
if (p->p_sigparent == SIGCHLD)
childproc_exited(p);
else /* LINUX thread */
psignal(p->p_pptr, p->p_sigparent);
}
sx_xunlock(&proctree_lock);
/*
* The state PRS_ZOMBIE prevents other proesses from sending
* signal to the process, to avoid memory leak, we free memory
* for signal queue at the time when the state is set.
*/
sigqueue_flush(&p->p_sigqueue);
sigqueue_flush(&td->td_sigqueue);
/*
* We have to wait until after acquiring all locks before
* changing p_state. We need to avoid all possible context
* switches (including ones from blocking on a mutex) while
* marked as a zombie. We also have to set the zombie state
* before we release the parent process' proc lock to avoid
* a lost wakeup. So, we first call wakeup, then we grab the
* sched lock, update the state, and release the parent process'
* proc lock.
*/
wakeup(p->p_pptr);
cv_broadcast(&p->p_pwait);
sched_exit(p->p_pptr, td);
PROC_SLOCK(p);
p->p_state = PRS_ZOMBIE;
PROC_UNLOCK(p->p_pptr);
/*
* Hopefully no one will try to deliver a signal to the process this
* late in the game.
*/
knlist_destroy(&p->p_klist);
/*
* Save our children's rusage information in our exit rusage.
*/
ruadd(&p->p_ru, &p->p_rux, &p->p_stats->p_cru, &p->p_crux);
/*
* Make sure the scheduler takes this thread out of its tables etc.
* This will also release this thread's reference to the ucred.
* Other thread parts to release include pcb bits and such.
*/
thread_exit();
}
/*
* cdevsw interface to km driver.
*/
int
kmopen(dev_t dev, int flag, __unused int devtype, proc_t pp)
{
int unit;
struct tty *tp;
struct winsize *wp;
int ret;
unit = minor(dev);
if(unit >= 1)
return (ENXIO);
tp = km_tty[unit];
tty_lock(tp);
tp->t_oproc = kmstart;
tp->t_param = NULL;
tp->t_dev = dev;
if ( !(tp->t_state & TS_ISOPEN) ) {
tp->t_iflag = TTYDEF_IFLAG;
tp->t_oflag = TTYDEF_OFLAG;
tp->t_cflag = (CREAD | CS8 | CLOCAL);
tp->t_lflag = TTYDEF_LFLAG;
tp->t_ispeed = tp->t_ospeed = TTYDEF_SPEED;
termioschars(&tp->t_termios);
ttsetwater(tp);
} else if ((tp->t_state & TS_XCLUDE) && proc_suser(pp)) {
ret = EBUSY;
goto out;
}
tp->t_state |= TS_CARR_ON; /* lie and say carrier exists and is on. */
ret = ((*linesw[tp->t_line].l_open)(dev, tp));
{
PE_Video video;
wp = &tp->t_winsize;
/*
* Magic numbers. These are CHARWIDTH and CHARHEIGHT
* from osfmk/ppc/POWERMAC/video_console.c
*/
wp->ws_xpixel = 8;
wp->ws_ypixel = 16;
tty_unlock(tp); /* XXX race window */
if (flag & O_POPUP)
PE_initialize_console(0, kPETextScreen);
bzero(&video, sizeof(video));
PE_current_console(&video);
tty_lock(tp);
if( video.v_width != 0 && video.v_height != 0 ) {
wp->ws_col = video.v_width / wp->ws_xpixel;
wp->ws_row = video.v_height / wp->ws_ypixel;
} else {
wp->ws_col = 100;
wp->ws_row = 36;
}
}
out:
tty_unlock(tp);
return ret;
}
int tty_set_ldisc(struct tty_struct *tty, int ldisc)
{
int retval;
struct tty_ldisc *o_ldisc, *new_ldisc;
int work, o_work = 0;
struct tty_struct *o_tty;
new_ldisc = tty_ldisc_get(ldisc);
if (IS_ERR(new_ldisc))
return PTR_ERR(new_ldisc);
tty_lock();
/*
* We need to look at the tty locking here for pty/tty pairs
* when both sides try to change in parallel.
*/
o_tty = tty->link; /* o_tty is the pty side or NULL */
/*
* Check the no-op case
*/
if (tty->ldisc->ops->num == ldisc) {
tty_unlock();
tty_ldisc_put(new_ldisc);
return 0;
}
tty_unlock();
/*
* Problem: What do we do if this blocks ?
* We could deadlock here
*/
tty_wait_until_sent(tty, 0);
tty_lock();
mutex_lock(&tty->ldisc_mutex);
/*
* We could be midstream of another ldisc change which has
* dropped the lock during processing. If so we need to wait.
*/
while (test_bit(TTY_LDISC_CHANGING, &tty->flags)) {
mutex_unlock(&tty->ldisc_mutex);
tty_unlock();
wait_event(tty_ldisc_wait,
test_bit(TTY_LDISC_CHANGING, &tty->flags) == 0);
tty_lock();
mutex_lock(&tty->ldisc_mutex);
}
set_bit(TTY_LDISC_CHANGING, &tty->flags);
/*
* No more input please, we are switching. The new ldisc
* will update this value in the ldisc open function
*/
tty->receive_room = 0;
o_ldisc = tty->ldisc;
tty_unlock();
/*
* Make sure we don't change while someone holds a
* reference to the line discipline. The TTY_LDISC bit
* prevents anyone taking a reference once it is clear.
* We need the lock to avoid racing reference takers.
*
* We must clear the TTY_LDISC bit here to avoid a livelock
* with a userspace app continually trying to use the tty in
* parallel to the change and re-referencing the tty.
*/
work = tty_ldisc_halt(tty);
if (o_tty)
o_work = tty_ldisc_halt(o_tty);
/*
* Wait for ->hangup_work and ->buf.work handlers to terminate.
* We must drop the mutex here in case a hangup is also in process.
*/
mutex_unlock(&tty->ldisc_mutex);
tty_ldisc_flush_works(tty);
retval = tty_ldisc_wait_idle(tty, 5 * HZ);
tty_lock();
mutex_lock(&tty->ldisc_mutex);
/* handle wait idle failure locked */
if (retval) {
tty_ldisc_put(new_ldisc);
goto enable;
}
if (test_bit(TTY_HUPPING, &tty->flags)) {
/* We were raced by the hangup method. It will have stomped
the ldisc data and closed the ldisc down */
clear_bit(TTY_LDISC_CHANGING, &tty->flags);
mutex_unlock(&tty->ldisc_mutex);
tty_ldisc_put(new_ldisc);
tty_unlock();
return -EIO;
}
/* Shutdown the current discipline. */
tty_ldisc_close(tty, o_ldisc);
/* Now set up the new line discipline. */
tty_ldisc_assign(tty, new_ldisc);
tty_set_termios_ldisc(tty, ldisc);
retval = tty_ldisc_open(tty, new_ldisc);
if (retval < 0) {
/* Back to the old one or N_TTY if we can't */
tty_ldisc_put(new_ldisc);
tty_ldisc_restore(tty, o_ldisc);
}
/* At this point we hold a reference to the new ldisc and a
a reference to the old ldisc. If we ended up flipping back
to the existing ldisc we have two references to it */
if (tty->ldisc->ops->num != o_ldisc->ops->num && tty->ops->set_ldisc)
tty->ops->set_ldisc(tty);
tty_ldisc_put(o_ldisc);
enable:
/*
* Allow ldisc referencing to occur again
*/
tty_ldisc_enable(tty);
if (o_tty)
tty_ldisc_enable(o_tty);
/* Restart the work queue in case no characters kick it off. Safe if
already running */
if (work)
schedule_work(&tty->buf.work);
if (o_work)
schedule_work(&o_tty->buf.work);
mutex_unlock(&tty->ldisc_mutex);
tty_unlock();
return retval;
}
void tty_ldisc_hangup(struct tty_struct *tty)
{
struct tty_ldisc *ld;
int reset = tty->driver->flags & TTY_DRIVER_RESET_TERMIOS;
int err = 0;
/*
* FIXME! What are the locking issues here? This may me overdoing
* things... This question is especially important now that we've
* removed the irqlock.
*/
ld = tty_ldisc_ref(tty);
if (ld != NULL) {
/* We may have no line discipline at this point */
if (ld->ops->flush_buffer)
ld->ops->flush_buffer(tty);
tty_driver_flush_buffer(tty);
if ((test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) &&
ld->ops->write_wakeup)
ld->ops->write_wakeup(tty);
if (ld->ops->hangup)
ld->ops->hangup(tty);
tty_ldisc_deref(ld);
}
/*
* FIXME: Once we trust the LDISC code better we can wait here for
* ldisc completion and fix the driver call race
*/
wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
wake_up_interruptible_poll(&tty->read_wait, POLLIN);
/*
* Shutdown the current line discipline, and reset it to
* N_TTY if need be.
*
* Avoid racing set_ldisc or tty_ldisc_release
*/
mutex_lock(&tty->ldisc_mutex);
/*
* this is like tty_ldisc_halt, but we need to give up
* the BTM before calling cancel_work_sync, which may
* need to wait for another function taking the BTM
*/
clear_bit(TTY_LDISC, &tty->flags);
tty_unlock();
cancel_work_sync(&tty->buf.work);
mutex_unlock(&tty->ldisc_mutex);
retry:
tty_lock();
mutex_lock(&tty->ldisc_mutex);
/* At this point we have a closed ldisc and we want to
reopen it. We could defer this to the next open but
it means auditing a lot of other paths so this is
a FIXME */
if (tty->ldisc) { /* Not yet closed */
if (atomic_read(&tty->ldisc->users) != 1) {
char cur_n[TASK_COMM_LEN], tty_n[64];
long timeout = 3 * HZ;
tty_unlock();
while (tty_ldisc_wait_idle(tty, timeout) == -EBUSY) {
timeout = MAX_SCHEDULE_TIMEOUT;
printk_ratelimited(KERN_WARNING
"%s: waiting (%s) for %s took too long, but we keep waiting...\n",
__func__, get_task_comm(cur_n, current),
tty_name(tty, tty_n));
}
mutex_unlock(&tty->ldisc_mutex);
goto retry;
}
if (reset == 0) {
if (!tty_ldisc_reinit(tty, tty->termios->c_line))
err = tty_ldisc_open(tty, tty->ldisc);
else
err = 1;
}
/* If the re-open fails or we reset then go to N_TTY. The
N_TTY open cannot fail */
if (reset || err) {
BUG_ON(tty_ldisc_reinit(tty, N_TTY));
WARN_ON(tty_ldisc_open(tty, tty->ldisc));
}
tty_ldisc_enable(tty);
}
mutex_unlock(&tty->ldisc_mutex);
if (reset)
tty_reset_termios(tty);
}
/*
* ------------------------------------------------------------
* rs_open() and friends
* ------------------------------------------------------------
*/
static int block_til_ready(struct tty_struct *tty, struct file * filp,
struct m68k_serial *info)
{
DECLARE_WAITQUEUE(wait, current);
int retval;
int do_clocal = 0;
/*
* If the device is in the middle of being closed, then block
* until it's done, and then try again.
*/
if (info->flags & S_CLOSING) {
interruptible_sleep_on(&info->close_wait);
#ifdef SERIAL_DO_RESTART
if (info->flags & S_HUP_NOTIFY)
return -EAGAIN;
else
return -ERESTARTSYS;
#else
return -EAGAIN;
#endif
}
/*
* If non-blocking mode is set, or the port is not enabled,
* then make the check up front and then exit.
*/
if ((filp->f_flags & O_NONBLOCK) ||
(tty->flags & (1 << TTY_IO_ERROR))) {
info->flags |= S_NORMAL_ACTIVE;
return 0;
}
if (tty->termios->c_cflag & CLOCAL)
do_clocal = 1;
/*
* Block waiting for the carrier detect and the line to become
* free (i.e., not in use by the callout). While we are in
* this loop, info->count is dropped by one, so that
* rs_close() knows when to free things. We restore it upon
* exit, either normal or abnormal.
*/
retval = 0;
add_wait_queue(&info->open_wait, &wait);
info->count--;
info->blocked_open++;
while (1) {
local_irq_disable();
m68k_rtsdtr(info, 1);
local_irq_enable();
current->state = TASK_INTERRUPTIBLE;
if (tty_hung_up_p(filp) ||
!(info->flags & S_INITIALIZED)) {
#ifdef SERIAL_DO_RESTART
if (info->flags & S_HUP_NOTIFY)
retval = -EAGAIN;
else
retval = -ERESTARTSYS;
#else
retval = -EAGAIN;
#endif
break;
}
if (!(info->flags & S_CLOSING) && do_clocal)
break;
if (signal_pending(current)) {
retval = -ERESTARTSYS;
break;
}
tty_unlock();
schedule();
tty_lock();
}
current->state = TASK_RUNNING;
remove_wait_queue(&info->open_wait, &wait);
if (!tty_hung_up_p(filp))
info->count++;
info->blocked_open--;
if (retval)
return retval;
info->flags |= S_NORMAL_ACTIVE;
return 0;
}
int
ttyinq_read_uio(struct ttyinq *ti, struct tty *tp, struct uio *uio,
size_t rlen, size_t flen)
{
MPASS(rlen <= uio->uio_resid);
while (rlen > 0) {
int error;
struct ttyinq_block *tib;
size_t cbegin, cend, clen;
/* See if there still is data. */
if (ti->ti_begin == ti->ti_linestart)
return (0);
tib = ti->ti_firstblock;
if (tib == NULL)
return (0);
/*
* The end address should be the lowest of these three:
* - The write pointer
* - The blocksize - we can't read beyond the block
* - The end address if we could perform the full read
*/
cbegin = ti->ti_begin;
cend = MIN(MIN(ti->ti_linestart, ti->ti_begin + rlen),
TTYINQ_DATASIZE);
clen = cend - cbegin;
MPASS(clen >= flen);
rlen -= clen;
/*
* We can prevent buffering in some cases:
* - We need to read the block until the end.
* - We don't need to read the block until the end, but
* there is no data beyond it, which allows us to move
* the write pointer to a new block.
*/
if (cend == TTYINQ_DATASIZE || cend == ti->ti_end) {
/*
* Fast path: zero copy. Remove the first block,
* so we can unlock the TTY temporarily.
*/
TTYINQ_REMOVE_HEAD(ti);
ti->ti_begin = 0;
/*
* Because we remove the first block, we must
* fix up the block offsets.
*/
#define CORRECT_BLOCK(t) do { \
if (t <= TTYINQ_DATASIZE) \
t = 0; \
else \
t -= TTYINQ_DATASIZE; \
} while (0)
CORRECT_BLOCK(ti->ti_linestart);
CORRECT_BLOCK(ti->ti_reprint);
CORRECT_BLOCK(ti->ti_end);
#undef CORRECT_BLOCK
/*
* Temporary unlock and copy the data to
* userspace. We may need to flush trailing
* bytes, like EOF characters.
*/
tty_unlock(tp);
error = uiomove(tib->tib_data + cbegin,
clen - flen, uio);
tty_lock(tp);
/* Block can now be readded to the list. */
TTYINQ_RECYCLE(ti, tib);
} else {
char ob[TTYINQ_DATASIZE - 1];
/*
* Slow path: store data in a temporary buffer.
*/
memcpy(ob, tib->tib_data + cbegin, clen - flen);
ti->ti_begin += clen;
MPASS(ti->ti_begin < TTYINQ_DATASIZE);
/* Temporary unlock and copy the data to userspace. */
tty_unlock(tp);
error = uiomove(ob, clen - flen, uio);
tty_lock(tp);
}
if (error != 0)
return (error);
if (tty_gone(tp))
return (ENXIO);
}
return (0);
}
static int
ptsdev_ioctl(struct file *fp, u_long cmd, void *data,
struct ucred *active_cred, struct thread *td)
{
struct tty *tp = fp->f_data;
struct pts_softc *psc = tty_softc(tp);
int error = 0, sig;
switch (cmd) {
case FIONBIO:
/* This device supports non-blocking operation. */
return (0);
case FIONREAD:
tty_lock(tp);
if (psc->pts_flags & PTS_FINISHED) {
/* Force read() to be called. */
*(int *)data = 1;
} else {
*(int *)data = ttydisc_getc_poll(tp);
}
tty_unlock(tp);
return (0);
case FIODGNAME: {
struct fiodgname_arg *fgn;
const char *p;
int i;
/* Reverse device name lookups, for ptsname() and ttyname(). */
fgn = data;
p = tty_devname(tp);
i = strlen(p) + 1;
if (i > fgn->len)
return (EINVAL);
return copyout(p, fgn->buf, i);
}
/*
* We need to implement TIOCGPGRP and TIOCGSID here again. When
* called on the pseudo-terminal master, it should not check if
* the terminal is the foreground terminal of the calling
* process.
*
* TIOCGETA is also implemented here. Various Linux PTY routines
* often call isatty(), which is implemented by tcgetattr().
*/
#ifdef PTS_LINUX
case TIOCGETA:
/* Obtain terminal flags through tcgetattr(). */
tty_lock(tp);
*(struct termios*)data = tp->t_termios;
tty_unlock(tp);
return (0);
#endif /* PTS_LINUX */
case TIOCSETAF:
case TIOCSETAW:
/*
* We must make sure we turn tcsetattr() calls of TCSAFLUSH and
* TCSADRAIN into something different. If an application would
* call TCSAFLUSH or TCSADRAIN on the master descriptor, it may
* deadlock waiting for all data to be read.
*/
cmd = TIOCSETA;
break;
#if defined(PTS_COMPAT) || defined(PTS_LINUX)
case TIOCGPTN:
/*
* Get the device unit number.
*/
if (psc->pts_unit < 0)
return (ENOTTY);
*(unsigned int *)data = psc->pts_unit;
return (0);
#endif /* PTS_COMPAT || PTS_LINUX */
case TIOCGPGRP:
/* Get the foreground process group ID. */
tty_lock(tp);
if (tp->t_pgrp != NULL)
*(int *)data = tp->t_pgrp->pg_id;
else
*(int *)data = NO_PID;
tty_unlock(tp);
return (0);
case TIOCGSID:
/* Get the session leader process ID. */
tty_lock(tp);
if (tp->t_session == NULL)
error = ENOTTY;
else
*(int *)data = tp->t_session->s_sid;
tty_unlock(tp);
return (error);
case TIOCPTMASTER:
/* Yes, we are a pseudo-terminal master. */
return (0);
case TIOCSIG:
/* Signal the foreground process group. */
sig = *(int *)data;
if (sig < 1 || sig >= NSIG)
return (EINVAL);
tty_lock(tp);
tty_signal_pgrp(tp, sig);
tty_unlock(tp);
return (0);
case TIOCPKT:
/* Enable/disable packet mode. */
tty_lock(tp);
if (*(int *)data)
psc->pts_flags |= PTS_PKT;
else
psc->pts_flags &= ~PTS_PKT;
tty_unlock(tp);
return (0);
}
/* Just redirect this ioctl to the slave device. */
tty_lock(tp);
error = tty_ioctl(tp, cmd, data, fp->f_flag, td);
tty_unlock(tp);
if (error == ENOIOCTL)
error = ENOTTY;
return (error);
}
static ssize_t r3964_write(struct tty_struct *tty, struct file *file,
const unsigned char *data, size_t count)
{
struct r3964_info *pInfo = tty->disc_data;
struct r3964_block_header *pHeader;
struct r3964_client_info *pClient;
unsigned char *new_data;
TRACE_L("write request, %d characters", count);
/*
* Verify the pointers
*/
if (!pInfo)
return -EIO;
/*
* Ensure that the caller does not wish to send too much.
*/
if (count > R3964_MTU) {
if (pInfo->flags & R3964_DEBUG) {
TRACE_L(KERN_WARNING "r3964_write: truncating user "
"packet from %u to mtu %d", count, R3964_MTU);
}
count = R3964_MTU;
}
/*
* Allocate a buffer for the data and copy it from the buffer with header prepended
*/
new_data = kmalloc(count + sizeof(struct r3964_block_header),
GFP_KERNEL);
TRACE_M("r3964_write - kmalloc %p", new_data);
if (new_data == NULL) {
if (pInfo->flags & R3964_DEBUG) {
printk(KERN_ERR "r3964_write: no memory\n");
}
return -ENOSPC;
}
pHeader = (struct r3964_block_header *)new_data;
pHeader->data = new_data + sizeof(struct r3964_block_header);
pHeader->length = count;
pHeader->locks = 0;
pHeader->owner = NULL;
tty_lock();
pClient = findClient(pInfo, task_pid(current));
if (pClient) {
pHeader->owner = pClient;
}
memcpy(pHeader->data, data, count); /* We already verified this */
if (pInfo->flags & R3964_DEBUG) {
dump_block(pHeader->data, count);
}
/*
* Add buffer to transmit-queue:
*/
add_tx_queue(pInfo, pHeader);
trigger_transmit(pInfo);
tty_unlock();
return 0;
}
static int
ptsdev_read(struct file *fp, struct uio *uio, struct ucred *active_cred,
int flags, struct thread *td)
{
struct tty *tp = fp->f_data;
struct pts_softc *psc = tty_softc(tp);
int error = 0;
char pkt;
if (uio->uio_resid == 0)
return (0);
tty_lock(tp);
for (;;) {
/*
* Implement packet mode. When packet mode is turned on,
* the first byte contains a bitmask of events that
* occured (start, stop, flush, window size, etc).
*/
if (psc->pts_flags & PTS_PKT && psc->pts_pkt) {
pkt = psc->pts_pkt;
psc->pts_pkt = 0;
tty_unlock(tp);
error = ureadc(pkt, uio);
return (error);
}
/*
* Transmit regular data.
*
* XXX: We shouldn't use ttydisc_getc_poll()! Even
* though in this implementation, there is likely going
* to be data, we should just call ttydisc_getc_uio()
* and use its return value to sleep.
*/
if (ttydisc_getc_poll(tp)) {
if (psc->pts_flags & PTS_PKT) {
/*
* XXX: Small race. Fortunately PTY
* consumers aren't multithreaded.
*/
tty_unlock(tp);
error = ureadc(TIOCPKT_DATA, uio);
if (error)
return (error);
tty_lock(tp);
}
error = ttydisc_getc_uio(tp, uio);
break;
}
/* Maybe the device isn't used anyway. */
if (psc->pts_flags & PTS_FINISHED)
break;
/* Wait for more data. */
if (fp->f_flag & O_NONBLOCK) {
error = EWOULDBLOCK;
break;
}
error = cv_wait_sig(&psc->pts_outwait, tp->t_mtx);
if (error != 0)
break;
}
tty_unlock(tp);
return (error);
}
static int
ptsdev_write(struct file *fp, struct uio *uio, struct ucred *active_cred,
int flags, struct thread *td)
{
struct tty *tp = fp->f_data;
struct pts_softc *psc = tty_softc(tp);
char ib[256], *ibstart;
size_t iblen, rintlen;
int error = 0;
if (uio->uio_resid == 0)
return (0);
for (;;) {
ibstart = ib;
iblen = MIN(uio->uio_resid, sizeof ib);
error = uiomove(ib, iblen, uio);
tty_lock(tp);
if (error != 0) {
iblen = 0;
goto done;
}
/*
* When possible, avoid the slow path. rint_bypass()
* copies all input to the input queue at once.
*/
MPASS(iblen > 0);
do {
rintlen = ttydisc_rint_simple(tp, ibstart, iblen);
ibstart += rintlen;
iblen -= rintlen;
if (iblen == 0) {
/* All data written. */
break;
}
/* Maybe the device isn't used anyway. */
if (psc->pts_flags & PTS_FINISHED) {
error = EIO;
goto done;
}
/* Wait for more data. */
if (fp->f_flag & O_NONBLOCK) {
error = EWOULDBLOCK;
goto done;
}
/* Wake up users on the slave side. */
ttydisc_rint_done(tp);
error = cv_wait_sig(&psc->pts_inwait, tp->t_mtx);
if (error != 0)
goto done;
} while (iblen > 0);
if (uio->uio_resid == 0)
break;
tty_unlock(tp);
}
done: ttydisc_rint_done(tp);
tty_unlock(tp);
/*
* Don't account for the part of the buffer that we couldn't
* pass to the TTY.
*/
uio->uio_resid += iblen;
return (error);
}
void
si_intr(void *arg)
{
struct si_softc *sc;
struct si_port *pp;
volatile struct si_channel *ccbp;
struct tty *tp;
volatile caddr_t maddr;
BYTE op, ip;
int x, card, port, n, i, isopen;
volatile BYTE *z;
BYTE c;
sc = arg;
mtx_assert(&Giant, MA_OWNED);
DPRINT((0, arg == NULL ? DBG_POLL:DBG_INTR, "si_intr\n"));
/*
* When we get an int we poll all the channels and do ALL pending
* work, not just the first one we find. This allows all cards to
* share the same vector.
*
* XXX - But if we're sharing the vector with something that's NOT
* a SI/XIO/SX card, we may be making more work for ourselves.
*/
for (card = 0; card < si_numunits; card++) {
sc = devclass_get_softc(si_devclass, card);
if (sc == NULL || sc->sc_type == SIEMPTY)
continue;
/*
* First, clear the interrupt
*/
switch(sc->sc_type) {
case SIHOST:
maddr = sc->sc_maddr;
((volatile struct si_reg *)maddr)->int_pending = 0;
/* flag nothing pending */
*(maddr+SIINTCL) = 0x00; /* Set IRQ clear */
*(maddr+SIINTCL_CL) = 0x00; /* Clear IRQ clear */
break;
case SIHOST2:
maddr = sc->sc_maddr;
((volatile struct si_reg *)maddr)->int_pending = 0;
*(maddr+SIPLIRQCLR) = 0x00;
*(maddr+SIPLIRQCLR) = 0x10;
break;
case SIPCI:
maddr = sc->sc_maddr;
((volatile struct si_reg *)maddr)->int_pending = 0;
*(maddr+SIPCIINTCL) = 0x0;
break;
case SIJETPCI: /* fall through to JETISA case */
case SIJETISA:
maddr = sc->sc_maddr;
((volatile struct si_reg *)maddr)->int_pending = 0;
*(maddr+SIJETINTCL) = 0x0;
break;
#ifdef DEV_EISA
case SIEISA:
maddr = sc->sc_maddr;
((volatile struct si_reg *)maddr)->int_pending = 0;
(void)inb(sc->sc_iobase + 3);
break;
#endif
case SIEMPTY:
default:
continue;
}
((volatile struct si_reg *)maddr)->int_scounter = 0;
/*
* check each port
*/
for (pp = sc->sc_ports, port = 0; port < sc->sc_nport;
pp++, port++) {
ccbp = pp->sp_ccb;
tp = pp->sp_tty;
tty_lock(tp);
/*
* See if a command has completed ?
*/
if (ccbp->hi_stat != pp->sp_pend) {
DPRINT((pp, DBG_INTR,
"si_intr hi_stat = %s, pend = %s\n",
si_cmdname(ccbp->hi_stat),
si_cmdname(pp->sp_pend)));
switch(pp->sp_pend) {
case LOPEN:
case MPEND:
case MOPEN:
case FCLOSE:
case CONFIG:
case SBREAK:
case EBREAK:
/* sleeping in si_command */
DPRINT((pp, DBG_INTR, "do wakeup\n"));
wakeup(&pp->sp_state);
break;
}
pp->sp_pend = ccbp->hi_stat;
}
/*
* Continue on if it's closed
*/
if (ccbp->hi_stat == IDLE_CLOSE) {
tty_unlock(tp);
continue;
}
/*
* Do modem state change if not a local device
*/
si_modem_state(pp, tp, ccbp->hi_ip);
/*
* Check to see if we should 'receive' characters.
*/
isopen = tty_opened(tp);
/*
* Do input break processing
*/
if (ccbp->hi_state & ST_BREAK) {
if (isopen)
ttydisc_rint(tp, 0, TRE_BREAK);
ccbp->hi_state &= ~ST_BREAK; /* A Bit iffy this */
DPRINT((pp, DBG_INTR, "si_intr break\n"));
}
/*
* Do RX stuff - if not open then dump any characters.
* XXX: This is VERY messy and needs to be cleaned up.
*
* XXX: can we leave data in the host adapter buffer
* when the clists are full? That may be dangerous
* if the user cannot get an interrupt signal through.
*/
more_rx:
if (!isopen) {
DPRINT((pp, DBG_INTR, "intr1: not open\n"));
ccbp->hi_rxopos = ccbp->hi_rxipos;
goto end_rx;
}
#if 0 /* XXXMPSAFETTY */
/*
* If the tty input buffers are blocked, stop emptying
* the incoming buffers and let the auto flow control
* assert..
*/
if (tp->t_state & TS_TBLOCK)
goto end_rx;
#endif
/*
* Process read characters if not skipped above
*/
op = ccbp->hi_rxopos;
ip = ccbp->hi_rxipos;
c = ip - op;
if (c == 0)
goto end_rx;
n = c & 0xff;
if (n > 250)
n = 250;
DPRINT((pp, DBG_INTR, "n = %d, op = %d, ip = %d\n",
n, op, ip));
/*
* Suck characters out of host card buffer into the
* "input staging buffer" - so that we dont leave the
* host card in limbo while we're possibly echoing
* characters and possibly flushing input inside the
* ldisc l_rint() routine.
*/
if (n <= SI_BUFFERSIZE - op) {
z = ccbp->hi_rxbuf + op;
si_vbcopy(z, si_rxbuf, n);
op += n;
} else {
x = SI_BUFFERSIZE - op;
z = ccbp->hi_rxbuf + op;
si_vbcopy(z, si_rxbuf, x);
z = ccbp->hi_rxbuf;
si_vbcopy(z, si_rxbuf + x, n - x);
op += n;
}
/* clear collected characters from buffer */
ccbp->hi_rxopos = op;
/*
* at this point...
* n = number of chars placed in si_rxbuf
*/
if (0 && ttydisc_can_bypass(tp)) {
i = ttydisc_rint_bypass(tp, (char *)si_rxbuf, n);
if (i < n)
pp->sp_delta_overflows += (n - i);
} else {
/*
* It'd be nice to not have to go through the
* function call overhead for each char here.
* It'd be nice to block input it, saving a
* loop here and the call/return overhead.
*/
for(x = 0; x < n; x++) {
i = si_rxbuf[x];
if (ttydisc_rint(tp, i, 0) == -1)
pp->sp_delta_overflows++;
}
}
goto more_rx; /* try for more until RXbuf is empty */
end_rx:
ttydisc_rint_done(tp);
/*
* Do TX stuff
*/
si_start(tp);
tty_unlock(tp);
} /* end of for (all ports on this controller) */
} /* end of for (all controllers) */
DPRINT((0, arg == NULL ? DBG_POLL:DBG_INTR, "end si_intr\n"));
}
/*
* An optimized version of ttyoutq_read() which can be used in pseudo
* TTY drivers to directly copy data from the outq to userspace, instead
* of buffering it.
*
* We can only copy data directly if we need to read the entire block
* back to the user, because we temporarily remove the block from the
* queue. Otherwise we need to copy it to a temporary buffer first, to
* make sure data remains in the correct order.
*/
int
ttyoutq_read_uio(struct ttyoutq *to, struct tty *tp, struct uio *uio)
{
while (uio->uio_resid > 0) {
int error;
struct ttyoutq_block *tob;
size_t cbegin, cend, clen;
/* See if there still is data. */
if (to->to_begin == to->to_end)
return (0);
tob = to->to_firstblock;
if (tob == NULL)
return (0);
/*
* The end address should be the lowest of these three:
* - The write pointer
* - The blocksize - we can't read beyond the block
* - The end address if we could perform the full read
*/
cbegin = to->to_begin;
cend = MIN(MIN(to->to_end, to->to_begin + uio->uio_resid),
TTYOUTQ_DATASIZE);
clen = cend - cbegin;
/*
* We can prevent buffering in some cases:
* - We need to read the block until the end.
* - We don't need to read the block until the end, but
* there is no data beyond it, which allows us to move
* the write pointer to a new block.
*/
if (cend == TTYOUTQ_DATASIZE || cend == to->to_end) {
/*
* Fast path: zero copy. Remove the first block,
* so we can unlock the TTY temporarily.
*/
TTYOUTQ_REMOVE_HEAD(to);
to->to_begin = 0;
if (to->to_end <= TTYOUTQ_DATASIZE)
to->to_end = 0;
else
to->to_end -= TTYOUTQ_DATASIZE;
/* Temporary unlock and copy the data to userspace. */
tty_unlock(tp);
error = uiomove(tob->tob_data + cbegin, clen, uio);
tty_lock(tp);
/* Block can now be readded to the list. */
TTYOUTQ_RECYCLE(to, tob);
} else {
char ob[TTYOUTQ_DATASIZE - 1];
/*
* Slow path: store data in a temporary buffer.
*/
memcpy(ob, tob->tob_data + cbegin, clen);
to->to_begin += clen;
MPASS(to->to_begin < TTYOUTQ_DATASIZE);
/* Temporary unlock and copy the data to userspace. */
tty_unlock(tp);
error = uiomove(ob, clen, uio);
tty_lock(tp);
}
if (error != 0)
return (error);
}
return (0);
}
static int set_serial_info(struct tty_struct *tty, struct serial_state *state,
struct serial_struct __user * new_info)
{
struct tty_port *port = &state->tport;
struct serial_struct new_serial;
bool change_spd;
int retval = 0;
if (copy_from_user(&new_serial,new_info,sizeof(new_serial)))
return -EFAULT;
tty_lock(tty);
change_spd = ((new_serial.flags ^ port->flags) & ASYNC_SPD_MASK) ||
new_serial.custom_divisor != state->custom_divisor;
if (new_serial.irq || new_serial.port != state->port ||
new_serial.xmit_fifo_size != state->xmit_fifo_size) {
tty_unlock(tty);
return -EINVAL;
}
if (!serial_isroot()) {
if ((new_serial.baud_base != state->baud_base) ||
(new_serial.close_delay != port->close_delay) ||
(new_serial.xmit_fifo_size != state->xmit_fifo_size) ||
((new_serial.flags & ~ASYNC_USR_MASK) !=
(port->flags & ~ASYNC_USR_MASK))) {
tty_unlock(tty);
return -EPERM;
}
port->flags = ((port->flags & ~ASYNC_USR_MASK) |
(new_serial.flags & ASYNC_USR_MASK));
state->custom_divisor = new_serial.custom_divisor;
goto check_and_exit;
}
if (new_serial.baud_base < 9600) {
tty_unlock(tty);
return -EINVAL;
}
/*
* OK, past this point, all the error checking has been done.
* At this point, we start making changes.....
*/
state->baud_base = new_serial.baud_base;
port->flags = ((port->flags & ~ASYNC_FLAGS) |
(new_serial.flags & ASYNC_FLAGS));
state->custom_divisor = new_serial.custom_divisor;
port->close_delay = new_serial.close_delay * HZ/100;
port->closing_wait = new_serial.closing_wait * HZ/100;
port->low_latency = (port->flags & ASYNC_LOW_LATENCY) ? 1 : 0;
check_and_exit:
if (tty_port_initialized(port)) {
if (change_spd) {
/* warn about deprecation unless clearing */
if (new_serial.flags & ASYNC_SPD_MASK)
dev_warn_ratelimited(tty->dev, "use of SPD flags is deprecated\n");
change_speed(tty, state, NULL);
}
} else
retval = startup(tty, state);
tty_unlock(tty);
return retval;
}
void tty_ldisc_hangup(struct tty_struct *tty)
{
struct tty_ldisc *ld;
int reset = tty->driver->flags & TTY_DRIVER_RESET_TERMIOS;
int err = 0;
tty_ldisc_debug(tty, "closing ldisc: %p\n", tty->ldisc);
ld = tty_ldisc_ref(tty);
if (ld != NULL) {
if (ld->ops->flush_buffer)
ld->ops->flush_buffer(tty);
tty_driver_flush_buffer(tty);
if ((test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) &&
ld->ops->write_wakeup)
ld->ops->write_wakeup(tty);
if (ld->ops->hangup)
ld->ops->hangup(tty);
tty_ldisc_deref(ld);
}
wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
wake_up_interruptible_poll(&tty->read_wait, POLLIN);
tty_unlock(tty);
/*
* Shutdown the current line discipline, and reset it to
* N_TTY if need be.
*
* Avoid racing set_ldisc or tty_ldisc_release
*/
tty_ldisc_lock_pair(tty, tty->link);
tty_lock(tty);
if (tty->ldisc) {
/* At this point we have a halted ldisc; we want to close it and
reopen a new ldisc. We could defer the reopen to the next
open but it means auditing a lot of other paths so this is
a FIXME */
if (reset == 0) {
if (!tty_ldisc_reinit(tty, tty->termios.c_line))
err = tty_ldisc_open(tty, tty->ldisc);
else
err = 1;
}
/* If the re-open fails or we reset then go to N_TTY. The
N_TTY open cannot fail */
if (reset || err) {
BUG_ON(tty_ldisc_reinit(tty, N_TTY));
WARN_ON(tty_ldisc_open(tty, tty->ldisc));
}
}
tty_ldisc_enable_pair(tty, tty->link);
if (reset)
tty_reset_termios(tty);
tty_ldisc_debug(tty, "re-opened ldisc: %p\n", tty->ldisc);
}
int tty_set_ldisc(struct tty_struct *tty, int ldisc)
{
int retval;
struct tty_ldisc *o_ldisc, *new_ldisc;
struct tty_struct *o_tty = tty->link;
new_ldisc = tty_ldisc_get(tty, ldisc);
if (IS_ERR(new_ldisc))
return PTR_ERR(new_ldisc);
retval = tty_ldisc_lock_pair_timeout(tty, o_tty, 5 * HZ);
if (retval) {
tty_ldisc_put(new_ldisc);
return retval;
}
/*
* Check the no-op case
*/
if (tty->ldisc->ops->num == ldisc) {
tty_ldisc_enable_pair(tty, o_tty);
tty_ldisc_put(new_ldisc);
return 0;
}
/* FIXME: why 'shutoff' input if the ldisc is locked? */
tty->receive_room = 0;
o_ldisc = tty->ldisc;
tty_lock(tty);
/* FIXME: for testing only */
WARN_ON(test_bit(TTY_HUPPED, &tty->flags));
if (test_bit(TTY_HUPPING, &tty->flags)) {
/* We were raced by the hangup method. It will have stomped
the ldisc data and closed the ldisc down */
tty_ldisc_enable_pair(tty, o_tty);
tty_ldisc_put(new_ldisc);
tty_unlock(tty);
return -EIO;
}
/* Shutdown the current discipline. */
tty_ldisc_close(tty, o_ldisc);
/* Now set up the new line discipline. */
tty->ldisc = new_ldisc;
tty_set_termios_ldisc(tty, ldisc);
retval = tty_ldisc_open(tty, new_ldisc);
if (retval < 0) {
/* Back to the old one or N_TTY if we can't */
tty_ldisc_put(new_ldisc);
tty_ldisc_restore(tty, o_ldisc);
}
/* At this point we hold a reference to the new ldisc and a
a reference to the old ldisc. If we ended up flipping back
to the existing ldisc we have two references to it */
if (tty->ldisc->ops->num != o_ldisc->ops->num && tty->ops->set_ldisc)
tty->ops->set_ldisc(tty);
tty_ldisc_put(o_ldisc);
/*
* Allow ldisc referencing to occur again
*/
tty_ldisc_enable_pair(tty, o_tty);
/* Restart the work queue in case no characters kick it off. Safe if
already running */
schedule_work(&tty->port->buf.work);
if (o_tty)
schedule_work(&o_tty->port->buf.work);
tty_unlock(tty);
return retval;
}