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-rw-r--r--drivers/char/pty.c719
1 files changed, 719 insertions, 0 deletions
diff --git a/drivers/char/pty.c b/drivers/char/pty.c
new file mode 100644
index 0000000..6d45827
--- /dev/null
+++ b/drivers/char/pty.c
@@ -0,0 +1,719 @@
+/*
+ * 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>
+ *
+ * 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>
+
+#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 <linux/device.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)
+{
+ BUG_ON(!tty);
+ if (tty->driver->subtype == PTY_TYPE_MASTER)
+ WARN_ON(tty->count > 1);
+ 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->link);
+#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.ops->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.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;
+}
+
+/* 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;
+ 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;
+ wake_up_interruptible(&to->read_wait);
+ spin_unlock_irqrestore(&tty->ctrl_lock, flags);
+ }
+}
+
+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 int pty_install(struct tty_driver *driver, struct tty_struct *tty)
+{
+ struct tty_struct *o_tty;
+ int idx = tty->index;
+ int retval;
+
+ o_tty = alloc_tty_struct();
+ if (!o_tty)
+ return -ENOMEM;
+ if (!try_module_get(driver->other->owner)) {
+ /* This cannot in fact currently happen */
+ free_tty_struct(o_tty);
+ return -ENOMEM;
+ }
+ initialize_tty_struct(o_tty, driver->other, idx);
+
+ /* We always use new tty termios data so we can do this
+ the easy way .. */
+ retval = tty_init_termios(tty);
+ if (retval)
+ goto free_mem_out;
+
+ retval = tty_init_termios(o_tty);
+ if (retval) {
+ tty_free_termios(tty);
+ goto free_mem_out;
+ }
+
+ /*
+ * Everything allocated ... set up the o_tty structure.
+ */
+ driver->other->ttys[idx] = o_tty;
+ tty_driver_kref_get(driver->other);
+ if (driver->subtype == PTY_TYPE_MASTER)
+ o_tty->count++;
+ /* Establish the links in both directions */
+ tty->link = o_tty;
+ o_tty->link = tty;
+
+ tty_driver_kref_get(driver);
+ tty->count++;
+ driver->ttys[idx] = tty;
+ return 0;
+free_mem_out:
+ module_put(o_tty->driver->owner);
+ free_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)
+{
+ 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 const struct tty_operations pty_ops_bsd = {
+ .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,
+ .ioctl = pty_bsd_ioctl,
+};
+
+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_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;
+static int pty_limit_max = NR_UNIX98_PTY_MAX;
+static int pty_count;
+
+static struct cdev ptmx_cdev;
+
+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,
+ .data = &pty_count,
+ .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;
+}
+
+/**
+ * ptm_unix98_lookup - find a pty master
+ * @driver: ptm driver
+ * @idx: tty index
+ *
+ * Look up a pty master device. Called under the tty_mutex for now.
+ * This provides our locking.
+ */
+
+static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver,
+ struct inode *ptm_inode, int idx)
+{
+ struct tty_struct *tty = devpts_get_tty(ptm_inode, idx);
+ if (tty)
+ tty = tty->link;
+ return tty;
+}
+
+/**
+ * pts_unix98_lookup - find a pty slave
+ * @driver: pts driver
+ * @idx: tty index
+ *
+ * Look up a pty master device. Called under the tty_mutex for now.
+ * This provides our locking.
+ */
+
+static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver,
+ struct inode *pts_inode, int idx)
+{
+ struct tty_struct *tty = devpts_get_tty(pts_inode, idx);
+ /* Master must be open before slave */
+ if (!tty)
+ return ERR_PTR(-EIO);
+ return tty;
+}
+
+static void pty_unix98_shutdown(struct tty_struct *tty)
+{
+ /* We have our own method as we don't use the tty index */
+ kfree(tty->termios);
+}
+
+/* We have no need to install and remove our tty objects as devpts does all
+ the work for us */
+
+static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty)
+{
+ struct tty_struct *o_tty;
+ int idx = tty->index;
+
+ o_tty = alloc_tty_struct();
+ if (!o_tty)
+ return -ENOMEM;
+ if (!try_module_get(driver->other->owner)) {
+ /* This cannot in fact currently happen */
+ free_tty_struct(o_tty);
+ return -ENOMEM;
+ }
+ initialize_tty_struct(o_tty, driver->other, idx);
+
+ 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 = 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 = o_tty->termios + 1;
+
+ tty_driver_kref_get(driver->other);
+ if (driver->subtype == PTY_TYPE_MASTER)
+ o_tty->count++;
+ /* Establish the links in both directions */
+ tty->link = o_tty;
+ o_tty->link = tty;
+ /*
+ * All structures have been allocated, so now we install them.
+ * Failures after this point use release_tty to clean up, so
+ * there's no need to null out the local pointers.
+ */
+ tty_driver_kref_get(driver);
+ tty->count++;
+ pty_count++;
+ return 0;
+free_mem_out:
+ kfree(o_tty->termios);
+ module_put(o_tty->driver->owner);
+ free_tty_struct(o_tty);
+ kfree(tty->termios);
+ return -ENOMEM;
+}
+
+static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
+{
+ pty_count--;
+}
+
+static const struct tty_operations ptm_unix98_ops = {
+ .lookup = ptm_unix98_lookup,
+ .install = pty_unix98_install,
+ .remove = pty_unix98_remove,
+ .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,
+ .ioctl = pty_unix98_ioctl,
+ .shutdown = pty_unix98_shutdown
+};
+
+static const struct tty_operations pty_unix98_ops = {
+ .lookup = pts_unix98_lookup,
+ .install = pty_unix98_install,
+ .remove = pty_unix98_remove,
+ .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,
+ .shutdown = pty_unix98_shutdown
+};
+
+/**
+ * ptmx_open - open a unix 98 pty master
+ * @inode: inode of device file
+ * @filp: file pointer to tty
+ *
+ * Allocate a unix98 pty master device from the ptmx driver.
+ *
+ * Locking: tty_mutex protects the init_dev work. tty->count should
+ * protect the rest.
+ * allocated_ptys_lock handles the list of free pty numbers
+ */
+
+static int __ptmx_open(struct inode *inode, struct file *filp)
+{
+ struct tty_struct *tty;
+ int retval;
+ int index;
+
+ nonseekable_open(inode, filp);
+
+ /* find a device that is not in use. */
+ index = devpts_new_index(inode);
+ if (index < 0)
+ return index;
+
+ mutex_lock(&tty_mutex);
+ tty = tty_init_dev(ptm_driver, index, 1);
+ mutex_unlock(&tty_mutex);
+
+ if (IS_ERR(tty)) {
+ retval = PTR_ERR(tty);
+ goto out;
+ }
+
+ set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
+ filp->private_data = tty;
+ file_move(filp, &tty->tty_files);
+
+ retval = devpts_pty_new(inode, tty->link);
+ if (retval)
+ goto out1;
+
+ retval = ptm_driver->ops->open(tty, filp);
+ if (!retval)
+ return 0;
+out1:
+ tty_release_dev(filp);
+ return retval;
+out:
+ devpts_kill_index(inode, index);
+ return retval;
+}
+
+static int ptmx_open(struct inode *inode, struct file *filp)
+{
+ int ret;
+
+ lock_kernel();
+ ret = __ptmx_open(inode, filp);
+ unlock_kernel();
+ return ret;
+}
+
+static struct file_operations ptmx_fops;
+
+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, &ptm_unix98_ops);
+
+ 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_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);
+
+ /* Now create the /dev/ptmx special device */
+ tty_default_fops(&ptmx_fops);
+ ptmx_fops.open = ptmx_open;
+
+ 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");
+ device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx");
+}
+
+#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);
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