*
* Added support for a Unix98-style ptmx device.
* -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
- * Added TTY_DO_WRITE_WAKEUP to enable n_tty to send POLL_OUT to
- * waiting writers -- Sapan Bhatia <sapan@corewars.org>
*
* When reading this code see also fs/devpts. In particular note that the
* driver_data field is used by the devpts side as a binding to the devpts
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/fcntl.h>
+#include <linux/sched.h>
#include <linux/string.h>
#include <linux/major.h>
#include <linux/mm.h>
#include <linux/init.h>
+#include <linux/smp_lock.h>
#include <linux/sysctl.h>
#include <linux/device.h>
#include <linux/uaccess.h>
#include <linux/bitops.h>
#include <linux/devpts_fs.h>
+#include <linux/slab.h>
#include <asm/system.h>
-/* These are global because they are accessed in tty_io.c */
#ifdef CONFIG_UNIX98_PTYS
-struct tty_driver *ptm_driver;
+static struct tty_driver *ptm_driver;
static struct tty_driver *pts_driver;
#endif
*/
static void pty_unthrottle(struct tty_struct *tty)
{
- struct tty_struct *o_tty = tty->link;
+ tty_wakeup(tty->link);
+ set_bit(TTY_THROTTLED, &tty->flags);
+}
- if (!o_tty)
- return;
+/**
+ * pty_space - report space left for writing
+ * @to: tty we are writing into
+ *
+ * The tty buffers allow 64K but we sneak a peak and clip at 8K this
+ * allows a lot of overspill room for echo and other fun messes to
+ * be handled properly
+ */
- tty_wakeup(o_tty);
- set_bit(TTY_THROTTLED, &tty->flags);
+static int pty_space(struct tty_struct *to)
+{
+ int n = 8192 - to->buf.memory_used;
+ if (n < 0)
+ return 0;
+ return n;
}
-/*
- * WSH 05/24/97: modified to
- * (1) use space in tty->flip instead of a shared temp buffer
- * The flip buffers aren't being used for a pty, so there's lots
- * of space available. The buffer is protected by a per-pty
- * semaphore that should almost never come under contention.
- * (2) avoid redundant copying for cases where count >> receive_room
- * N.B. Calls from user space may now return an error code instead of
- * a count.
+/**
+ * pty_write - write to a pty
+ * @tty: the tty we write from
+ * @buf: kernel buffer of data
+ * @count: bytes to write
*
- * FIXME: Our pty_write method is called with our ldisc lock held but
- * not our partners. We can't just take the other one blindly without
- * risking deadlocks.
+ * Our "hardware" write method. Data is coming from the ldisc which
+ * may be in a non sleeping state. We simply throw this at the other
+ * end of the link as if we were an IRQ handler receiving stuff for
+ * the other side of the pty/tty pair.
*/
-static int pty_write(struct tty_struct *tty, const unsigned char *buf,
- int count)
+
+static int pty_write(struct tty_struct *tty, const unsigned char *buf, int c)
{
struct tty_struct *to = tty->link;
- int c;
- if (!to || tty->stopped)
+ if (tty->stopped)
return 0;
- c = to->receive_room;
- if (c > count)
- c = count;
- to->ldisc.ops->receive_buf(to, buf, NULL, c);
-
+ if (c > 0) {
+ /* Stuff the data into the input queue of the other end */
+ c = tty_insert_flip_string(to, buf, c);
+ /* And shovel */
+ if (c) {
+ tty_flip_buffer_push(to);
+ tty_wakeup(tty);
+ }
+ }
return c;
}
+/**
+ * pty_write_room - write space
+ * @tty: tty we are writing from
+ *
+ * Report how many bytes the ldisc can send into the queue for
+ * the other device.
+ */
+
static int pty_write_room(struct tty_struct *tty)
{
- struct tty_struct *to = tty->link;
-
- if (!to || tty->stopped)
+ if (tty->stopped)
return 0;
-
- return to->receive_room;
+ return pty_space(tty->link);
}
-/*
- * WSH 05/24/97: Modified for asymmetric MASTER/SLAVE behavior
- * The chars_in_buffer() value is used by the ldisc select() function
- * to hold off writing when chars_in_buffer > WAKEUP_CHARS (== 256).
- * The pty driver chars_in_buffer() Master/Slave must behave differently:
- *
- * The Master side needs to allow typed-ahead commands to accumulate
- * while being canonicalized, so we report "our buffer" as empty until
- * some threshold is reached, and then report the count. (Any count >
- * WAKEUP_CHARS is regarded by select() as "full".) To avoid deadlock
- * the count returned must be 0 if no canonical data is available to be
- * read. (The N_TTY ldisc.chars_in_buffer now knows this.)
+/**
+ * pty_chars_in_buffer - characters currently in our tx queue
+ * @tty: our tty
*
- * The Slave side passes all characters in raw mode to the Master side's
- * buffer where they can be read immediately, so in this case we can
- * return the true count in the buffer.
+ * Report how much we have in the transmit queue. As everything is
+ * instantly at the other end this is easy to implement.
*/
+
static int pty_chars_in_buffer(struct tty_struct *tty)
{
- struct tty_struct *to = tty->link;
- int count;
-
- /* We should get the line discipline lock for "tty->link" */
- if (!to || !to->ldisc.ops->chars_in_buffer)
- return 0;
-
- /* The ldisc must report 0 if no characters available to be read */
- count = to->ldisc.ops->chars_in_buffer(to);
-
- if (tty->driver->subtype == PTY_TYPE_SLAVE)
- return count;
-
- /* Master side driver ... if the other side's read buffer is less than
- * half full, return 0 to allow writers to proceed; otherwise return
- * the count. This leaves a comfortable margin to avoid overflow,
- * and still allows half a buffer's worth of typed-ahead commands.
- */
- return (count < N_TTY_BUF_SIZE/2) ? 0 : count;
+ return 0;
}
/* Set the lock flag on a pty */
if (!to)
return;
-
- if (to->ldisc.ops->flush_buffer)
- to->ldisc.ops->flush_buffer(to);
-
+ /* tty_buffer_flush(to); FIXME */
if (to->packet) {
spin_lock_irqsave(&tty->ctrl_lock, flags);
tty->ctrl_status |= TIOCPKT_FLUSHWRITE;
clear_bit(TTY_OTHER_CLOSED, &tty->link->flags);
set_bit(TTY_THROTTLED, &tty->flags);
- set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
retval = 0;
out:
return retval;
tty->termios->c_cflag |= (CS8 | CREAD);
}
+/**
+ * pty_do_resize - resize event
+ * @tty: tty being resized
+ * @ws: window size being set.
+ *
+ * Update the termios variables and send the necessary signals to
+ * peform a terminal resize correctly
+ */
+
+int pty_resize(struct tty_struct *tty, struct winsize *ws)
+{
+ struct pid *pgrp, *rpgrp;
+ unsigned long flags;
+ struct tty_struct *pty = tty->link;
+
+ /* For a PTY we need to lock the tty side */
+ mutex_lock(&tty->termios_mutex);
+ if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
+ goto done;
+
+ /* Get the PID values and reference them so we can
+ avoid holding the tty ctrl lock while sending signals.
+ We need to lock these individually however. */
+
+ spin_lock_irqsave(&tty->ctrl_lock, flags);
+ pgrp = get_pid(tty->pgrp);
+ spin_unlock_irqrestore(&tty->ctrl_lock, flags);
+
+ spin_lock_irqsave(&pty->ctrl_lock, flags);
+ rpgrp = get_pid(pty->pgrp);
+ spin_unlock_irqrestore(&pty->ctrl_lock, flags);
+
+ if (pgrp)
+ kill_pgrp(pgrp, SIGWINCH, 1);
+ if (rpgrp != pgrp && rpgrp)
+ kill_pgrp(rpgrp, SIGWINCH, 1);
+
+ put_pid(pgrp);
+ put_pid(rpgrp);
+
+ tty->winsize = *ws;
+ pty->winsize = *ws; /* Never used so will go away soon */
+done:
+ mutex_unlock(&tty->termios_mutex);
+ return 0;
+}
+
+/* Traditional BSD devices */
+#ifdef CONFIG_LEGACY_PTYS
+
static int pty_install(struct tty_driver *driver, struct tty_struct *tty)
{
struct tty_struct *o_tty;
return -ENOMEM;
}
-
-static const struct tty_operations pty_ops = {
- .install = pty_install,
- .open = pty_open,
- .close = pty_close,
- .write = pty_write,
- .write_room = pty_write_room,
- .flush_buffer = pty_flush_buffer,
- .chars_in_buffer = pty_chars_in_buffer,
- .unthrottle = pty_unthrottle,
- .set_termios = pty_set_termios,
-};
-
-/* Traditional BSD devices */
-#ifdef CONFIG_LEGACY_PTYS
-static struct tty_driver *pty_driver, *pty_slave_driver;
-
static int pty_bsd_ioctl(struct tty_struct *tty, struct file *file,
unsigned int cmd, unsigned long arg)
{
static int legacy_count = CONFIG_LEGACY_PTY_COUNT;
module_param(legacy_count, int, 0);
-static const struct tty_operations pty_ops_bsd = {
+/*
+ * The master side of a pty can do TIOCSPTLCK and thus
+ * has pty_bsd_ioctl.
+ */
+static const struct tty_operations master_pty_ops_bsd = {
+ .install = pty_install,
.open = pty_open,
.close = pty_close,
.write = pty_write,
.unthrottle = pty_unthrottle,
.set_termios = pty_set_termios,
.ioctl = pty_bsd_ioctl,
+ .resize = pty_resize
+};
+
+static const struct tty_operations slave_pty_ops_bsd = {
+ .install = pty_install,
+ .open = pty_open,
+ .close = pty_close,
+ .write = pty_write,
+ .write_room = pty_write_room,
+ .flush_buffer = pty_flush_buffer,
+ .chars_in_buffer = pty_chars_in_buffer,
+ .unthrottle = pty_unthrottle,
+ .set_termios = pty_set_termios,
+ .resize = pty_resize
};
static void __init legacy_pty_init(void)
{
+ struct tty_driver *pty_driver, *pty_slave_driver;
+
if (legacy_count <= 0)
return;
pty_driver->init_termios.c_ospeed = 38400;
pty_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW;
pty_driver->other = pty_slave_driver;
- tty_set_operations(pty_driver, &pty_ops);
+ tty_set_operations(pty_driver, &master_pty_ops_bsd);
pty_slave_driver->owner = THIS_MODULE;
pty_slave_driver->driver_name = "pty_slave";
pty_slave_driver->flags = TTY_DRIVER_RESET_TERMIOS |
TTY_DRIVER_REAL_RAW;
pty_slave_driver->other = pty_driver;
- tty_set_operations(pty_slave_driver, &pty_ops);
+ tty_set_operations(pty_slave_driver, &slave_pty_ops_bsd);
if (tty_register_driver(pty_driver))
panic("Couldn't register pty driver");
static struct ctl_table pty_table[] = {
{
- .ctl_name = PTY_MAX,
.procname = "max",
.maxlen = sizeof(int),
.mode = 0644,
.data = &pty_limit,
- .proc_handler = &proc_dointvec_minmax,
- .strategy = &sysctl_intvec,
+ .proc_handler = proc_dointvec_minmax,
.extra1 = &pty_limit_min,
.extra2 = &pty_limit_max,
}, {
- .ctl_name = PTY_NR,
.procname = "nr",
.maxlen = sizeof(int),
.mode = 0444,
.data = &pty_count,
- .proc_handler = &proc_dointvec,
- }, {
- .ctl_name = 0
- }
+ .proc_handler = proc_dointvec,
+ },
+ {}
};
static struct ctl_table pty_kern_table[] = {
{
- .ctl_name = KERN_PTY,
.procname = "pty",
.mode = 0555,
.child = pty_table,
static struct ctl_table pty_root_table[] = {
{
- .ctl_name = CTL_KERN,
.procname = "kernel",
.mode = 0555,
.child = pty_kern_table,
{
/* We have our own method as we don't use the tty index */
kfree(tty->termios);
- kfree(tty->termios_locked);
}
/* We have no need to install and remove our tty objects as devpts does all
}
initialize_tty_struct(o_tty, driver->other, idx);
- tty->termios = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
+ tty->termios = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
if (tty->termios == NULL)
goto free_mem_out;
*tty->termios = driver->init_termios;
- tty->termios_locked = kzalloc(sizeof(struct ktermios), GFP_KERNEL);
- if (tty->termios_locked == NULL)
- goto free_mem_out;
- o_tty->termios = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
+ tty->termios_locked = tty->termios + 1;
+
+ o_tty->termios = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
if (o_tty->termios == NULL)
goto free_mem_out;
*o_tty->termios = driver->other->init_termios;
- o_tty->termios_locked = kzalloc(sizeof(struct ktermios), GFP_KERNEL);
- if (o_tty->termios_locked == NULL)
- goto free_mem_out;
+ o_tty->termios_locked = o_tty->termios + 1;
tty_driver_kref_get(driver->other);
if (driver->subtype == PTY_TYPE_MASTER)
pty_count++;
return 0;
free_mem_out:
- pty_unix98_shutdown(o_tty);
+ kfree(o_tty->termios);
module_put(o_tty->driver->owner);
free_tty_struct(o_tty);
- pty_unix98_shutdown(tty);
+ kfree(tty->termios);
return -ENOMEM;
}
.unthrottle = pty_unthrottle,
.set_termios = pty_set_termios,
.ioctl = pty_unix98_ioctl,
- .shutdown = pty_unix98_shutdown
+ .shutdown = pty_unix98_shutdown,
+ .resize = pty_resize
};
static const struct tty_operations pty_unix98_ops = {
if (!retval)
return 0;
out1:
- tty_release_dev(filp);
+ tty_release(inode, filp);
return retval;
out:
devpts_kill_index(inode, index);
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff