diff options
| -rw-r--r-- | drivers/char/pty.c | 86 |
1 files changed, 44 insertions, 42 deletions
diff --git a/drivers/char/pty.c b/drivers/char/pty.c index a391badef52a..c3ab8c3110c9 100644 --- a/drivers/char/pty.c +++ b/drivers/char/pty.c @@ -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 @@ out: 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); |