diff options
Diffstat (limited to 'drivers/char/pty.c')
| -rw-r--r-- | drivers/char/pty.c | 440 |
1 files changed, 0 insertions, 440 deletions
diff --git a/drivers/char/pty.c b/drivers/char/pty.c deleted file mode 100644 index 706ff34728f..00000000000 --- a/drivers/char/pty.c +++ /dev/null @@ -1,440 +0,0 @@ -/* - * linux/drivers/char/pty.c - * - * Copyright (C) 1991, 1992 Linus Torvalds - * - * 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> - * - * - */ - -#include <linux/module.h> /* For EXPORT_SYMBOL */ - -#include <linux/errno.h> -#include <linux/interrupt.h> -#include <linux/tty.h> -#include <linux/tty_flip.h> -#include <linux/fcntl.h> -#include <linux/string.h> -#include <linux/major.h> -#include <linux/mm.h> -#include <linux/init.h> -#include <linux/sysctl.h> - -#include <asm/uaccess.h> -#include <asm/system.h> -#include <linux/bitops.h> -#include <linux/devpts_fs.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) -{ - if (!tty) - return; - if (tty->driver->subtype == PTY_TYPE_MASTER) { - if (tty->count > 1) - printk("master pty_close: count = %d!!\n", tty->count); - } else { - if (tty->count > 2) - return; - } - wake_up_interruptible(&tty->read_wait); - wake_up_interruptible(&tty->write_wait); - tty->packet = 0; - if (!tty->link) - return; - tty->link->packet = 0; - set_bit(TTY_OTHER_CLOSED, &tty->link->flags); - wake_up_interruptible(&tty->link->read_wait); - wake_up_interruptible(&tty->link->write_wait); - if (tty->driver->subtype == PTY_TYPE_MASTER) { - set_bit(TTY_OTHER_CLOSED, &tty->flags); -#ifdef CONFIG_UNIX98_PTYS - if (tty->driver == ptm_driver) - devpts_pty_kill(tty->index); -#endif - tty_vhangup(tty->link); - } -} - -/* - * 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 - * 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) -{ - struct tty_struct *o_tty = tty->link; - - if (!o_tty) - return; - - tty_wakeup(o_tty); - set_bit(TTY_THROTTLED, &tty->flags); -} - -/* - * 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. - * - * 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. - */ -static int pty_write(struct tty_struct * tty, const unsigned char *buf, int count) -{ - struct tty_struct *to = tty->link; - int c; - - if (!to || tty->stopped) - return 0; - - c = to->receive_room; - if (c > count) - c = count; - to->ldisc.receive_buf(to, buf, NULL, c); - - return c; -} - -static int pty_write_room(struct tty_struct *tty) -{ - struct tty_struct *to = tty->link; - - if (!to || tty->stopped) - return 0; - - return to->receive_room; -} - -/* - * 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.) - * - * 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. - */ -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.chars_in_buffer) - return 0; - - /* The ldisc must report 0 if no characters available to be read */ - count = to->ldisc.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); -} - -/* Set the lock flag on a pty */ -static int pty_set_lock(struct tty_struct *tty, int __user * arg) -{ - int val; - if (get_user(val,arg)) - return -EFAULT; - if (val) - set_bit(TTY_PTY_LOCK, &tty->flags); - else - clear_bit(TTY_PTY_LOCK, &tty->flags); - return 0; -} - -static void pty_flush_buffer(struct tty_struct *tty) -{ - struct tty_struct *to = tty->link; - - if (!to) - return; - - if (to->ldisc.flush_buffer) - to->ldisc.flush_buffer(to); - - if (to->packet) { - tty->ctrl_status |= TIOCPKT_FLUSHWRITE; - wake_up_interruptible(&to->read_wait); - } -} - -static int pty_open(struct tty_struct *tty, struct file * filp) -{ - int retval = -ENODEV; - - if (!tty || !tty->link) - goto out; - - retval = -EIO; - if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) - goto out; - if (test_bit(TTY_PTY_LOCK, &tty->link->flags)) - goto out; - if (tty->link->count != 1) - goto out; - - 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; -} - -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); -} - -static const struct tty_operations pty_ops = { - .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) -{ - switch (cmd) { - case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */ - return pty_set_lock(tty, (int __user *) arg); - } - return -ENOIOCTLCMD; -} - -static int legacy_count = CONFIG_LEGACY_PTY_COUNT; -module_param(legacy_count, int, 0); - -static void __init legacy_pty_init(void) -{ - if (legacy_count <= 0) - return; - - pty_driver = alloc_tty_driver(legacy_count); - if (!pty_driver) - panic("Couldn't allocate pty driver"); - - pty_slave_driver = alloc_tty_driver(legacy_count); - if (!pty_slave_driver) - panic("Couldn't allocate pty slave driver"); - - pty_driver->owner = THIS_MODULE; - pty_driver->driver_name = "pty_master"; - pty_driver->name = "pty"; - pty_driver->major = PTY_MASTER_MAJOR; - pty_driver->minor_start = 0; - pty_driver->type = TTY_DRIVER_TYPE_PTY; - pty_driver->subtype = PTY_TYPE_MASTER; - pty_driver->init_termios = tty_std_termios; - pty_driver->init_termios.c_iflag = 0; - pty_driver->init_termios.c_oflag = 0; - pty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; - pty_driver->init_termios.c_lflag = 0; - pty_driver->init_termios.c_ispeed = 38400; - 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); - pty_driver->ioctl = pty_bsd_ioctl; - - pty_slave_driver->owner = THIS_MODULE; - pty_slave_driver->driver_name = "pty_slave"; - pty_slave_driver->name = "ttyp"; - pty_slave_driver->major = PTY_SLAVE_MAJOR; - pty_slave_driver->minor_start = 0; - pty_slave_driver->type = TTY_DRIVER_TYPE_PTY; - pty_slave_driver->subtype = PTY_TYPE_SLAVE; - pty_slave_driver->init_termios = tty_std_termios; - pty_slave_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; - pty_slave_driver->init_termios.c_ispeed = 38400; - pty_slave_driver->init_termios.c_ospeed = 38400; - 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); - - if (tty_register_driver(pty_driver)) - panic("Couldn't register pty driver"); - if (tty_register_driver(pty_slave_driver)) - panic("Couldn't register pty slave driver"); -} -#else -static inline void legacy_pty_init(void) { } -#endif - -/* Unix98 devices */ -#ifdef CONFIG_UNIX98_PTYS -/* - * sysctl support for setting limits on the number of Unix98 ptys allocated. - * 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_max = NR_UNIX98_PTY_MAX; - -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, - .extra1 = &pty_limit_min, - .extra2 = &pty_limit_max, - }, { - .ctl_name = PTY_NR, - .procname = "nr", - .maxlen = sizeof(int), - .mode = 0444, - .proc_handler = &proc_dointvec, - }, { - .ctl_name = 0 - } -}; - -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, - }, - {} -}; - - -static int pty_unix98_ioctl(struct tty_struct *tty, struct file *file, - unsigned int cmd, unsigned long arg) -{ - switch (cmd) { - case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */ - return pty_set_lock(tty, (int __user *)arg); - case TIOCGPTN: /* Get PT Number */ - return put_user(tty->index, (unsigned int __user *)arg); - } - - return -ENOIOCTLCMD; -} - -static void __init unix98_pty_init(void) -{ - ptm_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX); - if (!ptm_driver) - panic("Couldn't allocate Unix98 ptm driver"); - pts_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX); - if (!pts_driver) - panic("Couldn't allocate Unix98 pts driver"); - - ptm_driver->owner = THIS_MODULE; - ptm_driver->driver_name = "pty_master"; - ptm_driver->name = "ptm"; - ptm_driver->major = UNIX98_PTY_MASTER_MAJOR; - ptm_driver->minor_start = 0; - ptm_driver->type = TTY_DRIVER_TYPE_PTY; - ptm_driver->subtype = PTY_TYPE_MASTER; - ptm_driver->init_termios = tty_std_termios; - ptm_driver->init_termios.c_iflag = 0; - ptm_driver->init_termios.c_oflag = 0; - ptm_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; - ptm_driver->init_termios.c_lflag = 0; - ptm_driver->init_termios.c_ispeed = 38400; - ptm_driver->init_termios.c_ospeed = 38400; - ptm_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW | - TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM; - ptm_driver->other = pts_driver; - tty_set_operations(ptm_driver, &pty_ops); - ptm_driver->ioctl = pty_unix98_ioctl; - - pts_driver->owner = THIS_MODULE; - pts_driver->driver_name = "pty_slave"; - pts_driver->name = "pts"; - pts_driver->major = UNIX98_PTY_SLAVE_MAJOR; - pts_driver->minor_start = 0; - pts_driver->type = TTY_DRIVER_TYPE_PTY; - pts_driver->subtype = PTY_TYPE_SLAVE; - pts_driver->init_termios = tty_std_termios; - pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; - pts_driver->init_termios.c_ispeed = 38400; - pts_driver->init_termios.c_ospeed = 38400; - pts_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW | - TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM; - pts_driver->other = ptm_driver; - tty_set_operations(pts_driver, &pty_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"); - - pty_table[1].data = &ptm_driver->refcount; - register_sysctl_table(pty_root_table); -} -#else -static inline void unix98_pty_init(void) { } -#endif - -static int __init pty_init(void) -{ - legacy_pty_init(); - unix98_pty_init(); - return 0; -} -module_init(pty_init); |