mirror of https://gitee.com/openkylin/linux.git
pty: Coding style and polish
We've done the heavy lifting now its time to mop up a bit Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Alan Cox
Linus Torvalds
parent
a6f37daa8b
commit
fe9cd962a6
|
|
@ -8,10 +8,12 @@
|
|||
* 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
|
||||
* inode.
|
||||
*/
|
||||
|
||||
#include <linux/module.h> /* For EXPORT_SYMBOL */
|
||||
#include <linux/module.h>
|
||||
|
||||
#include <linux/errno.h>
|
||||
#include <linux/interrupt.h>
|
||||
|
|
@ -24,26 +26,24 @@
|
|||
#include <linux/init.h>
|
||||
#include <linux/sysctl.h>
|
||||
#include <linux/device.h>
|
||||
|
||||
#include <asm/uaccess.h>
|
||||
#include <asm/system.h>
|
||||
#include <linux/uaccess.h>
|
||||
#include <linux/bitops.h>
|
||||
#include <linux/devpts_fs.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 *pts_driver;
|
||||
#endif
|
||||
|
||||
static void pty_close(struct tty_struct * tty, struct file * filp)
|
||||
static void pty_close(struct tty_struct *tty, struct file *filp)
|
||||
{
|
||||
if (!tty)
|
||||
return;
|
||||
if (tty->driver->subtype == PTY_TYPE_MASTER) {
|
||||
if (tty->count > 1)
|
||||
printk("master pty_close: count = %d!!\n", tty->count);
|
||||
} else {
|
||||
BUG_ON(!tty);
|
||||
if (tty->driver->subtype == PTY_TYPE_MASTER)
|
||||
WARN_ON(tty->count > 1);
|
||||
else {
|
||||
if (tty->count > 2)
|
||||
return;
|
||||
}
|
||||
|
|
@ -70,13 +70,13 @@ static void pty_close(struct tty_struct * tty, struct file * filp)
|
|||
* The unthrottle routine is called by the line discipline to signal
|
||||
* that it can receive more characters. For PTY's, the TTY_THROTTLED
|
||||
* flag is always set, to force the line discipline to always call the
|
||||
* unthrottle routine when there are fewer than TTY_THRESHOLD_UNTHROTTLE
|
||||
* unthrottle routine when there are fewer than TTY_THRESHOLD_UNTHROTTLE
|
||||
* characters in the queue. This is necessary since each time this
|
||||
* happens, we need to wake up any sleeping processes that could be
|
||||
* (1) trying to send data to the pty, or (2) waiting in wait_until_sent()
|
||||
* for the pty buffer to be drained.
|
||||
*/
|
||||
static void pty_unthrottle(struct tty_struct * tty)
|
||||
static void pty_unthrottle(struct tty_struct *tty)
|
||||
{
|
||||
struct tty_struct *o_tty = tty->link;
|
||||
|
||||
|
|
@ -88,7 +88,7 @@ static void pty_unthrottle(struct tty_struct * tty)
|
|||
}
|
||||
|
||||
/*
|
||||
* WSH 05/24/97: modified to
|
||||
* 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
|
||||
|
|
@ -101,7 +101,8 @@ static void pty_unthrottle(struct tty_struct * tty)
|
|||
* not our partners. We can't just take the other one blindly without
|
||||
* risking deadlocks.
|
||||
*/
|
||||
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 count)
|
||||
{
|
||||
struct tty_struct *to = tty->link;
|
||||
int c;
|
||||
|
|
@ -113,7 +114,7 @@ static int pty_write(struct tty_struct * tty, const unsigned char *buf, int coun
|
|||
if (c > count)
|
||||
c = count;
|
||||
to->ldisc.ops->receive_buf(to, buf, NULL, c);
|
||||
|
||||
|
||||
return c;
|
||||
}
|
||||
|
||||
|
|
@ -129,17 +130,17 @@ static int pty_write_room(struct tty_struct *tty)
|
|||
|
||||
/*
|
||||
* WSH 05/24/97: Modified for asymmetric MASTER/SLAVE behavior
|
||||
* The chars_in_buffer() value is used by the ldisc select() function
|
||||
* 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
|
||||
* 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.)
|
||||
*
|
||||
*
|
||||
* 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.
|
||||
|
|
@ -156,21 +157,22 @@ static int pty_chars_in_buffer(struct tty_struct *tty)
|
|||
/* 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;
|
||||
if (tty->driver->subtype == PTY_TYPE_SLAVE)
|
||||
return count;
|
||||
|
||||
/* Master side driver ... if the other side's read buffer is less than
|
||||
/* 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,
|
||||
* 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 (count < N_TTY_BUF_SIZE/2) ? 0 : count;
|
||||
}
|
||||
|
||||
/* Set the lock flag on a pty */
|
||||
static int pty_set_lock(struct tty_struct *tty, int __user * arg)
|
||||
static int pty_set_lock(struct tty_struct *tty, int __user *arg)
|
||||
{
|
||||
int val;
|
||||
if (get_user(val,arg))
|
||||
if (get_user(val, arg))
|
||||
return -EFAULT;
|
||||
if (val)
|
||||
set_bit(TTY_PTY_LOCK, &tty->flags);
|
||||
|
|
@ -183,13 +185,13 @@ static void pty_flush_buffer(struct tty_struct *tty)
|
|||
{
|
||||
struct tty_struct *to = tty->link;
|
||||
unsigned long flags;
|
||||
|
||||
|
||||
if (!to)
|
||||
return;
|
||||
|
||||
|
||||
if (to->ldisc.ops->flush_buffer)
|
||||
to->ldisc.ops->flush_buffer(to);
|
||||
|
||||
|
||||
if (to->packet) {
|
||||
spin_lock_irqsave(&tty->ctrl_lock, flags);
|
||||
tty->ctrl_status |= TIOCPKT_FLUSHWRITE;
|
||||
|
|
@ -198,7 +200,7 @@ static void pty_flush_buffer(struct tty_struct *tty)
|
|||
}
|
||||
}
|
||||
|
||||
static int pty_open(struct tty_struct *tty, struct file * filp)
|
||||
static int pty_open(struct tty_struct *tty, struct file *filp)
|
||||
{
|
||||
int retval = -ENODEV;
|
||||
|
||||
|
|
@ -221,10 +223,11 @@ static int pty_open(struct tty_struct *tty, struct file * filp)
|
|||
return retval;
|
||||
}
|
||||
|
||||
static void pty_set_termios(struct tty_struct *tty, struct ktermios *old_termios)
|
||||
static void pty_set_termios(struct tty_struct *tty,
|
||||
struct ktermios *old_termios)
|
||||
{
|
||||
tty->termios->c_cflag &= ~(CSIZE | PARENB);
|
||||
tty->termios->c_cflag |= (CS8 | CREAD);
|
||||
tty->termios->c_cflag &= ~(CSIZE | PARENB);
|
||||
tty->termios->c_cflag |= (CS8 | CREAD);
|
||||
}
|
||||
|
||||
static int pty_install(struct tty_driver *driver, struct tty_struct *tty)
|
||||
|
|
@ -254,7 +257,7 @@ static int pty_install(struct tty_driver *driver, struct tty_struct *tty)
|
|||
tty_free_termios(tty);
|
||||
goto free_mem_out;
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* Everything allocated ... set up the o_tty structure.
|
||||
*/
|
||||
|
|
@ -381,9 +384,9 @@ static inline void legacy_pty_init(void) { }
|
|||
* Otherwise one can eat up all kernel memory by opening /dev/ptmx repeatedly.
|
||||
*/
|
||||
int pty_limit = NR_UNIX98_PTY_DEFAULT;
|
||||
static int pty_limit_min = 0;
|
||||
static int pty_limit_min;
|
||||
static int pty_limit_max = NR_UNIX98_PTY_MAX;
|
||||
static int pty_count = 0;
|
||||
static int pty_count;
|
||||
|
||||
static struct cdev ptmx_cdev;
|
||||
|
||||
|
|
@ -537,11 +540,10 @@ static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty)
|
|||
pty_count++;
|
||||
return 0;
|
||||
free_mem_out:
|
||||
kfree(o_tty->termios);
|
||||
pty_unix98_shutdown(o_tty);
|
||||
module_put(o_tty->driver->owner);
|
||||
free_tty_struct(o_tty);
|
||||
kfree(tty->termios_locked);
|
||||
kfree(tty->termios);
|
||||
pty_unix98_shutdown(tty);
|
||||
free_tty_struct(tty);
|
||||
module_put(driver->owner);
|
||||
return -ENOMEM;
|
||||
|
|
@ -691,13 +693,13 @@ static void __init unix98_pty_init(void)
|
|||
TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
|
||||
pts_driver->other = ptm_driver;
|
||||
tty_set_operations(pts_driver, &pty_unix98_ops);
|
||||
|
||||
|
||||
if (tty_register_driver(ptm_driver))
|
||||
panic("Couldn't register Unix98 ptm driver");
|
||||
if (tty_register_driver(pts_driver))
|
||||
panic("Couldn't register Unix98 pts driver");
|
||||
|
||||
register_sysctl_table(pty_root_table);
|
||||
register_sysctl_table(pty_root_table);
|
||||
|
||||
/* Now create the /dev/ptmx special device */
|
||||
tty_default_fops(&ptmx_fops);
|
||||
|
|
|
|||
Loading…
Reference in New Issue