#include <linux/smp_lock.h>
#include <linux/device.h>
#include <linux/idr.h>
+#include <linux/wait.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <linux/vt_kern.h>
#include <linux/selection.h>
#include <linux/devfs_fs_kernel.h>
+#include <linux/vs_cvirt.h>
#include <linux/kmod.h>
EXPORT_SYMBOL(tty_std_termios);
+/* This list gets poked at by procfs and various bits of boot up code. This
+ could do with some rationalisation such as pulling the tty proc function
+ into this file */
+
LIST_HEAD(tty_drivers); /* linked list of tty drivers */
-struct tty_ldisc ldiscs[NR_LDISCS]; /* line disc dispatch table */
-/* Semaphore to protect creating and releasing a tty */
+/* Semaphore to protect creating and releasing a tty. This is shared with
+ vt.c for deeply disgusting hack reasons */
DECLARE_MUTEX(tty_sem);
#ifdef CONFIG_UNIX98_PTYS
ssize_t redirected_tty_write(struct file *, const char __user *, size_t, loff_t *);
static unsigned int tty_poll(struct file *, poll_table *);
static int tty_open(struct inode *, struct file *);
+static int ptmx_open(struct inode *, struct file *);
static int tty_release(struct inode *, struct file *);
int tty_ioctl(struct inode * inode, struct file * file,
unsigned int cmd, unsigned long arg);
return 0;
}
+/*
+ * This is probably overkill for real world processors but
+ * they are not on hot paths so a little discipline won't do
+ * any harm.
+ */
+
+static void tty_set_termios_ldisc(struct tty_struct *tty, int num)
+{
+ down(&tty->termios_sem);
+ tty->termios->c_line = num;
+ up(&tty->termios_sem);
+}
+
+/*
+ * This guards the refcounted line discipline lists. The lock
+ * must be taken with irqs off because there are hangup path
+ * callers who will do ldisc lookups and cannot sleep.
+ */
+
+static spinlock_t tty_ldisc_lock = SPIN_LOCK_UNLOCKED;
+static DECLARE_WAIT_QUEUE_HEAD(tty_ldisc_wait);
+static struct tty_ldisc tty_ldiscs[NR_LDISCS]; /* line disc dispatch table */
+
int tty_register_ldisc(int disc, struct tty_ldisc *new_ldisc)
{
+ unsigned long flags;
+ int ret = 0;
+
if (disc < N_TTY || disc >= NR_LDISCS)
return -EINVAL;
+ spin_lock_irqsave(&tty_ldisc_lock, flags);
if (new_ldisc) {
- ldiscs[disc] = *new_ldisc;
- ldiscs[disc].flags |= LDISC_FLAG_DEFINED;
- ldiscs[disc].num = disc;
- } else
- memset(&ldiscs[disc], 0, sizeof(struct tty_ldisc));
+ tty_ldiscs[disc] = *new_ldisc;
+ tty_ldiscs[disc].num = disc;
+ tty_ldiscs[disc].flags |= LDISC_FLAG_DEFINED;
+ tty_ldiscs[disc].refcount = 0;
+ } else {
+ if(tty_ldiscs[disc].refcount)
+ ret = -EBUSY;
+ else
+ tty_ldiscs[disc].flags &= ~LDISC_FLAG_DEFINED;
+ }
+ spin_unlock_irqrestore(&tty_ldisc_lock, flags);
- return 0;
+ return ret;
}
EXPORT_SYMBOL(tty_register_ldisc);
-/* Set the discipline of a tty line. */
+struct tty_ldisc *tty_ldisc_get(int disc)
+{
+ unsigned long flags;
+ struct tty_ldisc *ld;
+
+ if (disc < N_TTY || disc >= NR_LDISCS)
+ return NULL;
+
+ spin_lock_irqsave(&tty_ldisc_lock, flags);
+
+ ld = &tty_ldiscs[disc];
+ /* Check the entry is defined */
+ if(ld->flags & LDISC_FLAG_DEFINED)
+ {
+ /* If the module is being unloaded we can't use it */
+ if (!try_module_get(ld->owner))
+ ld = NULL;
+ else /* lock it */
+ ld->refcount++;
+ }
+ else
+ ld = NULL;
+ spin_unlock_irqrestore(&tty_ldisc_lock, flags);
+ return ld;
+}
+
+EXPORT_SYMBOL_GPL(tty_ldisc_get);
+
+void tty_ldisc_put(int disc)
+{
+ struct tty_ldisc *ld;
+ unsigned long flags;
+
+ if (disc < N_TTY || disc >= NR_LDISCS)
+ BUG();
+
+ spin_lock_irqsave(&tty_ldisc_lock, flags);
+ ld = &tty_ldiscs[disc];
+ if(ld->refcount == 0)
+ BUG();
+ ld->refcount --;
+ module_put(ld->owner);
+ spin_unlock_irqrestore(&tty_ldisc_lock, flags);
+}
+
+EXPORT_SYMBOL_GPL(tty_ldisc_put);
+
+void tty_ldisc_assign(struct tty_struct *tty, struct tty_ldisc *ld)
+{
+ tty->ldisc = *ld;
+ tty->ldisc.refcount = 0;
+}
+
+/**
+ * tty_ldisc_try - internal helper
+ * @tty: the tty
+ *
+ * Make a single attempt to grab and bump the refcount on
+ * the tty ldisc. Return 0 on failure or 1 on success. This is
+ * used to implement both the waiting and non waiting versions
+ * of tty_ldisc_ref
+ */
+
+static int tty_ldisc_try(struct tty_struct *tty)
+{
+ unsigned long flags;
+ struct tty_ldisc *ld;
+ int ret = 0;
+
+ spin_lock_irqsave(&tty_ldisc_lock, flags);
+ ld = &tty->ldisc;
+ if(test_bit(TTY_LDISC, &tty->flags))
+ {
+ ld->refcount++;
+ ret = 1;
+ }
+ spin_unlock_irqrestore(&tty_ldisc_lock, flags);
+ return ret;
+}
+
+/**
+ * tty_ldisc_ref_wait - wait for the tty ldisc
+ * @tty: tty device
+ *
+ * Dereference the line discipline for the terminal and take a
+ * reference to it. If the line discipline is in flux then
+ * wait patiently until it changes.
+ *
+ * Note: Must not be called from an IRQ/timer context. The caller
+ * must also be careful not to hold other locks that will deadlock
+ * against a discipline change, such as an existing ldisc reference
+ * (which we check for)
+ */
+
+struct tty_ldisc *tty_ldisc_ref_wait(struct tty_struct *tty)
+{
+ /* wait_event is a macro */
+ wait_event(tty_ldisc_wait, tty_ldisc_try(tty));
+ if(tty->ldisc.refcount == 0)
+ printk(KERN_ERR "tty_ldisc_ref_wait\n");
+ return &tty->ldisc;
+}
+
+EXPORT_SYMBOL_GPL(tty_ldisc_ref_wait);
+
+/**
+ * tty_ldisc_ref - get the tty ldisc
+ * @tty: tty device
+ *
+ * Dereference the line discipline for the terminal and take a
+ * reference to it. If the line discipline is in flux then
+ * return NULL. Can be called from IRQ and timer functions.
+ */
+
+struct tty_ldisc *tty_ldisc_ref(struct tty_struct *tty)
+{
+ if(tty_ldisc_try(tty))
+ return &tty->ldisc;
+ return NULL;
+}
+
+EXPORT_SYMBOL_GPL(tty_ldisc_ref);
+
+/**
+ * tty_ldisc_deref - free a tty ldisc reference
+ * @ld: reference to free up
+ *
+ * Undoes the effect of tty_ldisc_ref or tty_ldisc_ref_wait. May
+ * be called in IRQ context.
+ */
+
+void tty_ldisc_deref(struct tty_ldisc *ld)
+{
+ unsigned long flags;
+
+ if(ld == NULL)
+ BUG();
+
+ spin_lock_irqsave(&tty_ldisc_lock, flags);
+ if(ld->refcount == 0)
+ printk(KERN_ERR "tty_ldisc_deref: no references.\n");
+ else
+ ld->refcount--;
+ if(ld->refcount == 0)
+ wake_up(&tty_ldisc_wait);
+ spin_unlock_irqrestore(&tty_ldisc_lock, flags);
+}
+
+EXPORT_SYMBOL_GPL(tty_ldisc_deref);
+
+/**
+ * tty_ldisc_enable - allow ldisc use
+ * @tty: terminal to activate ldisc on
+ *
+ * Set the TTY_LDISC flag when the line discipline can be called
+ * again. Do neccessary wakeups for existing sleepers.
+ *
+ * Note: nobody should set this bit except via this function. Clearing
+ * directly is allowed.
+ */
+
+static void tty_ldisc_enable(struct tty_struct *tty)
+{
+ set_bit(TTY_LDISC, &tty->flags);
+ wake_up(&tty_ldisc_wait);
+}
+
+/**
+ * tty_set_ldisc - set line discipline
+ * @tty: the terminal to set
+ * @ldisc: the line discipline
+ *
+ * Set the discipline of a tty line. Must be called from a process
+ * context.
+ */
+
static int tty_set_ldisc(struct tty_struct *tty, int ldisc)
{
int retval = 0;
struct tty_ldisc o_ldisc;
char buf[64];
+ int work;
+ unsigned long flags;
+ struct tty_ldisc *ld;
if ((ldisc < N_TTY) || (ldisc >= NR_LDISCS))
return -EINVAL;
+
+restart:
+
+ if (tty->ldisc.num == ldisc)
+ return 0; /* We are already in the desired discipline */
+
+ ld = tty_ldisc_get(ldisc);
/* Eduardo Blanco <ejbs@cs.cs.com.uy> */
/* Cyrus Durgin <cider@speakeasy.org> */
- if (!(ldiscs[ldisc].flags & LDISC_FLAG_DEFINED)) {
+ if (ld == NULL) {
request_module("tty-ldisc-%d", ldisc);
+ ld = tty_ldisc_get(ldisc);
}
- if (!(ldiscs[ldisc].flags & LDISC_FLAG_DEFINED))
+ if (ld == NULL)
return -EINVAL;
- if (tty->ldisc.num == ldisc)
- return 0; /* We are already in the desired discipline */
-
- if (!try_module_get(ldiscs[ldisc].owner))
- return -EINVAL;
-
o_ldisc = tty->ldisc;
tty_wait_until_sent(tty, 0);
+
+ /*
+ * 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.
+ */
+
+ spin_lock_irqsave(&tty_ldisc_lock, flags);
+ if(tty->ldisc.refcount)
+ {
+ /* Free the new ldisc we grabbed. Must drop the lock
+ first. */
+ spin_unlock_irqrestore(&tty_ldisc_lock, flags);
+ tty_ldisc_put(ldisc);
+ /*
+ * There are several reasons we may be busy, including
+ * random momentary I/O traffic. We must therefore
+ * retry. We could distinguish between blocking ops
+ * and retries if we made tty_ldisc_wait() smarter. That
+ * is up for discussion.
+ */
+ if(wait_event_interruptible(tty_ldisc_wait, tty->ldisc.refcount == 0) < 0)
+ return -ERESTARTSYS;
+ goto restart;
+ }
+ clear_bit(TTY_LDISC, &tty->flags);
+ clear_bit(TTY_DONT_FLIP, &tty->flags);
+ spin_unlock_irqrestore(&tty_ldisc_lock, flags);
+ /*
+ * From this point on we know nobody has an ldisc
+ * usage reference, nor can they obtain one until
+ * we say so later on.
+ */
+
+ work = cancel_delayed_work(&tty->flip.work);
+ /*
+ * Wait for ->hangup_work and ->flip.work handlers to terminate
+ */
+
+ flush_scheduled_work();
/* Shutdown the current discipline. */
if (tty->ldisc.close)
(tty->ldisc.close)(tty);
/* Now set up the new line discipline. */
- tty->ldisc = ldiscs[ldisc];
- tty->termios->c_line = ldisc;
+ tty_ldisc_assign(tty, ld);
+ tty_set_termios_ldisc(tty, ldisc);
if (tty->ldisc.open)
retval = (tty->ldisc.open)(tty);
if (retval < 0) {
- tty->ldisc = o_ldisc;
- tty->termios->c_line = tty->ldisc.num;
+ tty_ldisc_put(ldisc);
+ /* There is an outstanding reference here so this is safe */
+ tty_ldisc_assign(tty, tty_ldisc_get(o_ldisc.num));
+ tty_set_termios_ldisc(tty, tty->ldisc.num);
if (tty->ldisc.open && (tty->ldisc.open(tty) < 0)) {
- tty->ldisc = ldiscs[N_TTY];
- tty->termios->c_line = N_TTY;
+ tty_ldisc_put(o_ldisc.num);
+ /* This driver is always present */
+ tty_ldisc_assign(tty, tty_ldisc_get(N_TTY));
+ tty_set_termios_ldisc(tty, N_TTY);
if (tty->ldisc.open) {
int r = tty->ldisc.open(tty);
tty_name(tty, buf), r);
}
}
- } else {
- module_put(o_ldisc.owner);
}
+ /* 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.num != o_ldisc.num && tty->driver->set_ldisc)
tty->driver->set_ldisc(tty);
+
+ tty_ldisc_put(o_ldisc.num);
+
+ /*
+ * Allow ldisc referencing to occur as soon as the driver
+ * ldisc callback completes.
+ */
+
+ tty_ldisc_enable(tty);
+
+ /* Restart it in case no characters kick it off. Safe if
+ already running */
+ if(work)
+ schedule_delayed_work(&tty->flip.work, 1);
return retval;
}
.fasync = tty_fasync,
};
+#ifdef CONFIG_UNIX98_PTYS
+static struct file_operations ptmx_fops = {
+ .llseek = no_llseek,
+ .read = tty_read,
+ .write = tty_write,
+ .poll = tty_poll,
+ .ioctl = tty_ioctl,
+ .open = ptmx_open,
+ .release = tty_release,
+ .fasync = tty_fasync,
+};
+#endif
+
static struct file_operations console_fops = {
.llseek = no_llseek,
.read = tty_read,
static spinlock_t redirect_lock = SPIN_LOCK_UNLOCKED;
static struct file *redirect;
+
+/**
+ * tty_wakeup - request more data
+ * @tty: terminal
+ *
+ * Internal and external helper for wakeups of tty. This function
+ * informs the line discipline if present that the driver is ready
+ * to receive more output data.
+ */
+
+void tty_wakeup(struct tty_struct *tty)
+{
+ struct tty_ldisc *ld;
+
+ if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
+ ld = tty_ldisc_ref(tty);
+ if(ld) {
+ if(ld->write_wakeup)
+ ld->write_wakeup(tty);
+ tty_ldisc_deref(ld);
+ }
+ }
+ wake_up_interruptible(&tty->write_wait);
+}
+
+EXPORT_SYMBOL_GPL(tty_wakeup);
+
+/**
+ * tty_ldisc_flush - flush line discipline queue
+ * @tty: tty
+ *
+ * Flush the line discipline queue (if any) for this tty. If there
+ * is no line discipline active this is a no-op.
+ */
+
+void tty_ldisc_flush(struct tty_struct *tty)
+{
+ struct tty_ldisc *ld = tty_ldisc_ref(tty);
+ if(ld) {
+ if(ld->flush_buffer)
+ ld->flush_buffer(tty);
+ tty_ldisc_deref(ld);
+ }
+}
+
+EXPORT_SYMBOL_GPL(tty_ldisc_flush);
+
/*
* This can be called by the "eventd" kernel thread. That is process synchronous,
* but doesn't hold any locks, so we need to make sure we have the appropriate
struct file * cons_filp = NULL;
struct file *filp, *f = NULL;
struct task_struct *p;
- struct pid *pid;
+ struct tty_ldisc *ld;
int closecount = 0, n;
if (!tty)
check_tty_count(tty, "do_tty_hangup");
file_list_lock();
+ /* This breaks for file handles being sent over AF_UNIX sockets ? */
list_for_each_entry(filp, &tty->tty_files, f_list) {
if (filp->f_op->write == redirected_tty_write)
cons_filp = filp;
file_list_unlock();
/* FIXME! What are the locking issues here? This may me overdoing things..
- * this question is especially important now that we've removed the irqlock. */
- {
- unsigned long flags;
+ * this question is especially important now that we've removed the irqlock. */
- local_irq_save(flags); // FIXME: is this safe?
- if (tty->ldisc.flush_buffer)
- tty->ldisc.flush_buffer(tty);
+ ld = tty_ldisc_ref(tty);
+ if(ld != NULL) /* We may have no line discipline at this point */
+ {
+ if (ld->flush_buffer)
+ ld->flush_buffer(tty);
if (tty->driver->flush_buffer)
tty->driver->flush_buffer(tty);
if ((test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) &&
- tty->ldisc.write_wakeup)
- (tty->ldisc.write_wakeup)(tty);
- local_irq_restore(flags); // FIXME: is this safe?
+ ld->write_wakeup)
+ ld->write_wakeup(tty);
+ if (ld->hangup)
+ ld->hangup(tty);
}
+ /* FIXME: Once we trust the LDISC code better we can wait here for
+ ldisc completion and fix the driver call race */
+
wake_up_interruptible(&tty->write_wait);
wake_up_interruptible(&tty->read_wait);
* N_TTY.
*/
if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
+ {
+ down(&tty->termios_sem);
*tty->termios = tty->driver->init_termios;
- if (tty->ldisc.num != ldiscs[N_TTY].num) {
- if (tty->ldisc.close)
- (tty->ldisc.close)(tty);
- module_put(tty->ldisc.owner);
-
- tty->ldisc = ldiscs[N_TTY];
- tty->termios->c_line = N_TTY;
- if (tty->ldisc.open) {
- int i = (tty->ldisc.open)(tty);
- if (i < 0)
- printk(KERN_ERR "do_tty_hangup: N_TTY open: "
- "error %d\n", -i);
- }
+ up(&tty->termios_sem);
}
+ /* Defer ldisc switch */
+ /* tty_deferred_ldisc_switch(N_TTY);
+
+ This should get done automatically when the port closes and
+ tty_release is called */
+
read_lock(&tasklist_lock);
if (tty->session > 0) {
- struct list_head *l;
- for_each_task_pid(tty->session, PIDTYPE_SID, p, l, pid) {
+ do_each_task_pid(tty->session, PIDTYPE_SID, p) {
if (p->signal->tty == tty)
p->signal->tty = NULL;
if (!p->signal->leader)
send_group_sig_info(SIGCONT, SEND_SIG_PRIV, p);
if (tty->pgrp > 0)
p->signal->tty_old_pgrp = tty->pgrp;
- }
+ } while_each_task_pid(tty->session, PIDTYPE_SID, p);
}
read_unlock(&tasklist_lock);
tty->driver->close(tty, cons_filp);
} else if (tty->driver->hangup)
(tty->driver->hangup)(tty);
+
+ /* We don't want to have driver/ldisc interactions beyond
+ the ones we did here. The driver layer expects no
+ calls after ->hangup() from the ldisc side. However we
+ can't yet guarantee all that */
+
+ set_bit(TTY_HUPPED, &tty->flags);
+ if (ld) {
+ tty_ldisc_enable(tty);
+ tty_ldisc_deref(ld);
+ }
unlock_kernel();
if (f)
fput(f);
{
struct tty_struct *tty;
struct task_struct *p;
- struct list_head *l;
- struct pid *pid;
int tty_pgrp = -1;
lock_kernel();
tty->pgrp = -1;
read_lock(&tasklist_lock);
- for_each_task_pid(current->signal->session, PIDTYPE_SID, p, l, pid)
+ do_each_task_pid(current->signal->session, PIDTYPE_SID, p) {
p->signal->tty = NULL;
+ } while_each_task_pid(current->signal->session, PIDTYPE_SID, p);
read_unlock(&tasklist_lock);
unlock_kernel();
}
}
if (tty->driver->start)
(tty->driver->start)(tty);
- if ((test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) &&
- tty->ldisc.write_wakeup)
- (tty->ldisc.write_wakeup)(tty);
+
+ /* If we have a running line discipline it may need kicking */
+ tty_wakeup(tty);
wake_up_interruptible(&tty->write_wait);
}
int i;
struct tty_struct * tty;
struct inode *inode;
+ struct tty_ldisc *ld;
tty = (struct tty_struct *)file->private_data;
inode = file->f_dentry->d_inode;
if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
return -EIO;
+ /* We want to wait for the line discipline to sort out in this
+ situation */
+ ld = tty_ldisc_ref_wait(tty);
lock_kernel();
- if (tty->ldisc.read)
- i = (tty->ldisc.read)(tty,file,buf,count);
+ if (ld->read)
+ i = (ld->read)(tty,file,buf,count);
else
i = -EIO;
+ tty_ldisc_deref(ld);
unlock_kernel();
if (i > 0)
inode->i_atime = CURRENT_TIME;
{
struct tty_struct * tty;
struct inode *inode = file->f_dentry->d_inode;
-
+ ssize_t ret;
+ struct tty_ldisc *ld;
+
tty = (struct tty_struct *)file->private_data;
if (tty_paranoia_check(tty, inode, "tty_write"))
return -EIO;
if (!tty || !tty->driver->write || (test_bit(TTY_IO_ERROR, &tty->flags)))
return -EIO;
- if (!tty->ldisc.write)
- return -EIO;
- return do_tty_write(tty->ldisc.write, tty, file,
+
+ ld = tty_ldisc_ref_wait(tty);
+ if (!ld->write)
+ ret = -EIO;
+ else
+ ret = do_tty_write(ld->write, tty, file,
(const unsigned char __user *)buf, count);
+ tty_ldisc_deref(ld);
+ return ret;
}
ssize_t redirected_tty_write(struct file * file, const char __user * buf, size_t count,
return tty_write(file, buf, count, ppos);
}
+static char ptychar[] = "pqrstuvwxyzabcde";
+
+static inline void pty_line_name(struct tty_driver *driver, int index, char *p)
+{
+ int i = index + driver->name_base;
+ /* ->name is initialized to "ttyp", but "tty" is expected */
+ sprintf(p, "%s%c%x",
+ driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
+ ptychar[i >> 4 & 0xf], i & 0xf);
+}
+
static inline void tty_line_name(struct tty_driver *driver, int index, char *p)
{
sprintf(p, "%s%d", driver->name, index + driver->name_base);
* If we fail here just call release_mem to clean up. No need
* to decrement the use counts, as release_mem doesn't care.
*/
+
if (tty->ldisc.open) {
retval = (tty->ldisc.open)(tty);
if (retval)
(tty->ldisc.close)(tty);
goto release_mem_out;
}
+ tty_ldisc_enable(o_tty);
}
+ tty_ldisc_enable(tty);
goto success;
/*
tty->count++;
tty->driver = driver; /* N.B. why do this every time?? */
+ /* FIXME */
+ if(!test_bit(TTY_LDISC, &tty->flags))
+ printk(KERN_ERR "init_dev but no ldisc\n");
success:
*ret_tty = tty;
int devpts_master, devpts;
int idx;
char buf[64];
+ unsigned long flags;
tty = (struct tty_struct *)filp->private_data;
if (tty_paranoia_check(tty, filp->f_dentry->d_inode, "release_dev"))
}
}
#endif
-
if (tty->driver->close)
tty->driver->close(tty, filp);
*/
if (tty_closing || o_tty_closing) {
struct task_struct *p;
- struct list_head *l;
- struct pid *pid;
read_lock(&tasklist_lock);
- for_each_task_pid(tty->session, PIDTYPE_SID, p, l, pid)
+ do_each_task_pid(tty->session, PIDTYPE_SID, p) {
p->signal->tty = NULL;
+ } while_each_task_pid(tty->session, PIDTYPE_SID, p);
if (o_tty)
- for_each_task_pid(o_tty->session, PIDTYPE_SID, p,l, pid)
+ do_each_task_pid(o_tty->session, PIDTYPE_SID, p) {
p->signal->tty = NULL;
+ } while_each_task_pid(o_tty->session, PIDTYPE_SID, p);
read_unlock(&tasklist_lock);
}
#ifdef TTY_DEBUG_HANGUP
printk(KERN_DEBUG "freeing tty structure...");
#endif
-
/*
* Prevent flush_to_ldisc() from rescheduling the work for later. Then
- * kill any delayed work.
+ * kill any delayed work. As this is the final close it does not
+ * race with the set_ldisc code path.
*/
+ clear_bit(TTY_LDISC, &tty->flags);
clear_bit(TTY_DONT_FLIP, &tty->flags);
cancel_delayed_work(&tty->flip.work);
/*
* Wait for ->hangup_work and ->flip.work handlers to terminate
*/
+
flush_scheduled_work();
-
+
+ /*
+ * Wait for any short term users (we know they are just driver
+ * side waiters as the file is closing so user count on the file
+ * side is zero.
+ */
+ spin_lock_irqsave(&tty_ldisc_lock, flags);
+ while(tty->ldisc.refcount)
+ {
+ spin_unlock_irqrestore(&tty_ldisc_lock, flags);
+ wait_event(tty_ldisc_wait, tty->ldisc.refcount == 0);
+ spin_lock_irqsave(&tty_ldisc_lock, flags);
+ }
+ spin_unlock_irqrestore(&tty_ldisc_lock, flags);
/*
* Shutdown the current line discipline, and reset it to N_TTY.
* N.B. why reset ldisc when we're releasing the memory??
+ *
+ * FIXME: this MUST get fixed for the new reflocking
*/
if (tty->ldisc.close)
(tty->ldisc.close)(tty);
- module_put(tty->ldisc.owner);
+ tty_ldisc_put(tty->ldisc.num);
- tty->ldisc = ldiscs[N_TTY];
- tty->termios->c_line = N_TTY;
+ /*
+ * Switch the line discipline back
+ */
+ tty_ldisc_assign(tty, tty_ldisc_get(N_TTY));
+ tty_set_termios_ldisc(tty,N_TTY);
if (o_tty) {
+ /* FIXME: could o_tty be in setldisc here ? */
+ clear_bit(TTY_LDISC, &o_tty->flags);
if (o_tty->ldisc.close)
(o_tty->ldisc.close)(o_tty);
- module_put(o_tty->ldisc.owner);
- o_tty->ldisc = ldiscs[N_TTY];
+ tty_ldisc_put(o_tty->ldisc.num);
+ tty_ldisc_assign(o_tty, tty_ldisc_get(N_TTY));
+ tty_set_termios_ldisc(o_tty,N_TTY);
}
-
/*
* The release_mem function takes care of the details of clearing
* the slots and preserving the termios structure.
unsigned short saved_flags = filp->f_flags;
nonseekable_open(inode, filp);
+
retry_open:
noctty = filp->f_flags & O_NOCTTY;
index = -1;
return -ENODEV;
}
-#ifdef CONFIG_UNIX98_PTYS
- if (device == MKDEV(TTYAUX_MAJOR,2)) {
- int idr_ret;
-
- /* find a device that is not in use. */
- down(&allocated_ptys_lock);
- if (!idr_pre_get(&allocated_ptys, GFP_KERNEL)) {
- up(&allocated_ptys_lock);
- return -ENOMEM;
- }
- idr_ret = idr_get_new(&allocated_ptys, NULL, &index);
- if (idr_ret < 0) {
- up(&allocated_ptys_lock);
- if (idr_ret == -EAGAIN)
- return -ENOMEM;
- return -EIO;
- }
- if (index >= pty_limit) {
- idr_remove(&allocated_ptys, index);
- up(&allocated_ptys_lock);
- return -EIO;
- }
- up(&allocated_ptys_lock);
-
- driver = ptm_driver;
- retval = init_dev(driver, index, &tty);
- if (retval) {
- down(&allocated_ptys_lock);
- idr_remove(&allocated_ptys, index);
- up(&allocated_ptys_lock);
- return retval;
- }
-
- set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
- if (devpts_pty_new(tty->link))
- retval = -ENOMEM;
- } else
-#endif
- {
- driver = get_tty_driver(device, &index);
- if (!driver)
- return -ENODEV;
+ driver = get_tty_driver(device, &index);
+ if (!driver)
+ return -ENODEV;
got_driver:
- retval = init_dev(driver, index, &tty);
- if (retval)
- return retval;
- }
+ retval = init_dev(driver, index, &tty);
+ if (retval)
+ return retval;
filp->private_data = tty;
file_move(filp, &tty->tty_files);
printk(KERN_DEBUG "error %d in opening %s...", retval,
tty->name);
#endif
-
-#ifdef CONFIG_UNIX98_PTYS
- if (index != -1) {
- down(&allocated_ptys_lock);
- idr_remove(&allocated_ptys, index);
- up(&allocated_ptys_lock);
- }
-#endif
-
release_dev(filp);
if (retval != -ERESTARTSYS)
return retval;
return 0;
}
+#ifdef CONFIG_UNIX98_PTYS
+static int ptmx_open(struct inode * inode, struct file * filp)
+{
+ struct tty_struct *tty;
+ int retval;
+ int index;
+ int idr_ret;
+
+ nonseekable_open(inode, filp);
+
+ /* find a device that is not in use. */
+ down(&allocated_ptys_lock);
+ if (!idr_pre_get(&allocated_ptys, GFP_KERNEL)) {
+ up(&allocated_ptys_lock);
+ return -ENOMEM;
+ }
+ idr_ret = idr_get_new(&allocated_ptys, NULL, &index);
+ if (idr_ret < 0) {
+ up(&allocated_ptys_lock);
+ if (idr_ret == -EAGAIN)
+ return -ENOMEM;
+ return -EIO;
+ }
+ if (index >= pty_limit) {
+ idr_remove(&allocated_ptys, index);
+ up(&allocated_ptys_lock);
+ return -EIO;
+ }
+ up(&allocated_ptys_lock);
+
+ retval = init_dev(ptm_driver, index, &tty);
+ if (retval)
+ goto out;
+
+ set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
+ filp->private_data = tty;
+ file_move(filp, &tty->tty_files);
+
+ retval = -ENOMEM;
+ if (devpts_pty_new(tty->link))
+ goto out1;
+
+ check_tty_count(tty, "tty_open");
+ retval = ptm_driver->open(tty, filp);
+ if (!retval)
+ return 0;
+out1:
+ release_dev(filp);
+out:
+ down(&allocated_ptys_lock);
+ idr_remove(&allocated_ptys, index);
+ up(&allocated_ptys_lock);
+ return retval;
+}
+#endif
+
static int tty_release(struct inode * inode, struct file * filp)
{
lock_kernel();
static unsigned int tty_poll(struct file * filp, poll_table * wait)
{
struct tty_struct * tty;
+ struct tty_ldisc *ld;
+ int ret = 0;
tty = (struct tty_struct *)filp->private_data;
if (tty_paranoia_check(tty, filp->f_dentry->d_inode, "tty_poll"))
return 0;
-
- if (tty->ldisc.poll)
- return (tty->ldisc.poll)(tty, filp, wait);
- return 0;
+
+ ld = tty_ldisc_ref_wait(tty);
+ if (ld->poll)
+ ret = (ld->poll)(tty, filp, wait);
+ tty_ldisc_deref(ld);
+ return ret;
}
static int tty_fasync(int fd, struct file * filp, int on)
static int tiocsti(struct tty_struct *tty, char __user *p)
{
char ch, mbz = 0;
-
+ struct tty_ldisc *ld;
+
if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
return -EPERM;
if (get_user(ch, p))
return -EFAULT;
- tty->ldisc.receive_buf(tty, &ch, &mbz, 1);
+ ld = tty_ldisc_ref_wait(tty);
+ ld->receive_buf(tty, &ch, &mbz, 1);
+ tty_ldisc_deref(ld);
return 0;
}
static int tiocsctty(struct tty_struct *tty, int arg)
{
- struct list_head *l;
- struct pid *pid;
task_t *p;
if (current->signal->leader &&
*/
read_lock(&tasklist_lock);
- for_each_task_pid(tty->session, PIDTYPE_SID, p, l, pid)
+ do_each_task_pid(tty->session, PIDTYPE_SID, p) {
p->signal->tty = NULL;
+ } while_each_task_pid(tty->session, PIDTYPE_SID, p);
read_unlock(&tasklist_lock);
} else
return -EPERM;
static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
{
+ pid_t pgrp;
/*
* (tty == real_tty) is a cheap way of
* testing if the tty is NOT a master pty.
*/
if (tty == real_tty && current->signal->tty != real_tty)
return -ENOTTY;
- return put_user(real_tty->pgrp, p);
+
+ pgrp = vx_map_pid(real_tty->pgrp);
+ return put_user(pgrp, p);
}
static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
return -ENOTTY;
if (get_user(pgrp, p))
return -EFAULT;
+
+ pgrp = vx_rmap_pid(pgrp);
if (pgrp < 0)
return -EINVAL;
if (session_of_pgrp(pgrp) != current->signal->session)
struct tty_struct *tty, *real_tty;
void __user *p = (void __user *)arg;
int retval;
+ struct tty_ldisc *ld;
tty = (struct tty_struct *)file->private_data;
if (tty_paranoia_check(tty, inode, "tty_ioctl"))
case TIOCGSID:
return tiocgsid(tty, real_tty, p);
case TIOCGETD:
+ /* FIXME: check this is ok */
return put_user(tty->ldisc.num, (int __user *)p);
case TIOCSETD:
return tiocsetd(tty, p);
return tty_tiocmset(tty, file, cmd, p);
}
if (tty->driver->ioctl) {
- int retval = (tty->driver->ioctl)(tty, file, cmd, arg);
+ retval = (tty->driver->ioctl)(tty, file, cmd, arg);
if (retval != -ENOIOCTLCMD)
return retval;
}
- if (tty->ldisc.ioctl) {
- int retval = (tty->ldisc.ioctl)(tty, file, cmd, arg);
- if (retval != -ENOIOCTLCMD)
- return retval;
+ ld = tty_ldisc_ref_wait(tty);
+ retval = -EINVAL;
+ if (ld->ioctl) {
+ retval = ld->ioctl(tty, file, cmd, arg);
+ if (retval == -ENOIOCTLCMD)
+ retval = -EINVAL;
}
- return -EINVAL;
+ tty_ldisc_deref(ld);
+ return retval;
}
#else
struct tty_struct *tty = arg;
struct task_struct *p;
- struct list_head *l;
- struct pid *pid;
int session;
int i;
struct file *filp;
+ struct tty_ldisc *disc;
if (!tty)
return;
session = tty->session;
- if (tty->ldisc.flush_buffer)
- tty->ldisc.flush_buffer(tty);
+
+ /* We don't want an ldisc switch during this */
+ disc = tty_ldisc_ref(tty);
+ if (disc && disc->flush_buffer)
+ disc->flush_buffer(tty);
+ tty_ldisc_deref(disc);
+
if (tty->driver->flush_buffer)
tty->driver->flush_buffer(tty);
+
read_lock(&tasklist_lock);
- for_each_task_pid(session, PIDTYPE_SID, p, l, pid) {
+ do_each_task_pid(session, PIDTYPE_SID, p) {
if (p->signal->tty == tty || session > 0) {
printk(KERN_NOTICE "SAK: killed process %d"
" (%s): p->signal->session==tty->session\n",
spin_unlock(&p->files->file_lock);
}
task_unlock(p);
- }
+ } while_each_task_pid(session, PIDTYPE_SID, p);
read_unlock(&tasklist_lock);
#endif
}
/*
* This routine is called out of the software interrupt to flush data
- * from the flip buffer to the line discipline.
+ * from the flip buffer to the line discipline.
*/
+
static void flush_to_ldisc(void *private_)
{
struct tty_struct *tty = (struct tty_struct *) private_;
unsigned char *cp;
char *fp;
int count;
- unsigned long flags;
+ unsigned long flags;
+ struct tty_ldisc *disc;
+
+ disc = tty_ldisc_ref(tty);
+ if (disc == NULL) /* !TTY_LDISC */
+ return;
if (test_bit(TTY_DONT_FLIP, &tty->flags)) {
/*
* Do it after the next timer tick:
*/
schedule_delayed_work(&tty->flip.work, 1);
- return;
+ goto out;
}
-
spin_lock_irqsave(&tty->read_lock, flags);
if (tty->flip.buf_num) {
cp = tty->flip.char_buf + TTY_FLIPBUF_SIZE;
tty->flip.count = 0;
spin_unlock_irqrestore(&tty->read_lock, flags);
- tty->ldisc.receive_buf(tty, cp, fp, count);
+ disc->receive_buf(tty, cp, fp, count);
+out:
+ tty_ldisc_deref(disc);
+}
+
+/*
+ * Call the ldisc flush directly from a driver. This function may
+ * return an error and need retrying by the user.
+ */
+
+int tty_push_data(struct tty_struct *tty, unsigned char *cp, unsigned char *fp, int count)
+{
+ int ret = 0;
+ struct tty_ldisc *disc;
+
+ disc = tty_ldisc_ref(tty);
+ if(test_bit(TTY_DONT_FLIP, &tty->flags))
+ ret = -EAGAIN;
+ else if(disc == NULL)
+ ret = -EIO;
+ else
+ disc->receive_buf(tty, cp, fp, count);
+ tty_ldisc_deref(disc);
+ return ret;
+
}
/*
static int n_baud_table = ARRAY_SIZE(baud_table);
+/**
+ * tty_termios_baud_rate
+ * @termios: termios structure
+ *
+ * Convert termios baud rate data into a speed. This should be called
+ * with the termios lock held if this termios is a terminal termios
+ * structure. May change the termios data.
+ */
+
int tty_termios_baud_rate(struct termios *termios)
{
- unsigned int cbaud = termios->c_cflag & CBAUD;
+ unsigned int cbaud;
+
+ cbaud = termios->c_cflag & CBAUD;
if (cbaud & CBAUDEX) {
cbaud &= ~CBAUDEX;
else
cbaud += 15;
}
-
return baud_table[cbaud];
}
EXPORT_SYMBOL(tty_termios_baud_rate);
+/**
+ * tty_get_baud_rate - get tty bit rates
+ * @tty: tty to query
+ *
+ * Returns the baud rate as an integer for this terminal. The
+ * termios lock must be held by the caller and the terminal bit
+ * flags may be updated.
+ */
+
int tty_get_baud_rate(struct tty_struct *tty)
{
int baud = tty_termios_baud_rate(tty->termios);
EXPORT_SYMBOL(tty_get_baud_rate);
+/**
+ * tty_flip_buffer_push - terminal
+ * @tty: tty to push
+ *
+ * Queue a push of the terminal flip buffers to the line discipline. This
+ * function must not be called from IRQ context if tty->low_latency is set.
+ *
+ * In the event of the queue being busy for flipping the work will be
+ * held off and retried later.
+ */
+
void tty_flip_buffer_push(struct tty_struct *tty)
{
if (tty->low_latency)
{
memset(tty, 0, sizeof(struct tty_struct));
tty->magic = TTY_MAGIC;
- tty->ldisc = ldiscs[N_TTY];
+ tty_ldisc_assign(tty, tty_ldisc_get(N_TTY));
tty->pgrp = -1;
tty->flip.char_buf_ptr = tty->flip.char_buf;
tty->flip.flag_buf_ptr = tty->flip.flag_buf;
INIT_WORK(&tty->flip.work, flush_to_ldisc, tty);
init_MUTEX(&tty->flip.pty_sem);
+ init_MUTEX(&tty->termios_sem);
init_waitqueue_head(&tty->write_wait);
init_waitqueue_head(&tty->read_wait);
INIT_WORK(&tty->hangup_work, do_tty_hangup, tty);
void tty_register_device(struct tty_driver *driver, unsigned index,
struct device *device)
{
+ char name[64];
dev_t dev = MKDEV(driver->major, driver->minor_start) + index;
if (index >= driver->num) {
devfs_mk_cdev(dev, S_IFCHR | S_IRUSR | S_IWUSR,
"%s%d", driver->devfs_name, index + driver->name_base);
- /* we don't care about the ptys */
- /* how nice to hide this behind some crappy interface.. */
- if (driver->type != TTY_DRIVER_TYPE_PTY) {
- char name[64];
+ if (driver->type == TTY_DRIVER_TYPE_PTY)
+ pty_line_name(driver, index, name);
+ else
tty_line_name(driver, index, name);
- class_simple_device_add(tty_class, dev, device, name);
- }
+ class_simple_device_add(tty_class, dev, device, name);
}
/**
class_simple_device_add(tty_class, MKDEV(TTYAUX_MAJOR, 1), NULL, "console");
#ifdef CONFIG_UNIX98_PTYS
- cdev_init(&ptmx_cdev, &tty_fops);
+ cdev_init(&ptmx_cdev, &ptmx_fops);
if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) ||
register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0)
panic("Couldn't register /dev/ptmx driver\n");
git://git.onelab.eu / linux-2.6.git / blobdiff