| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Copyright (C) 1991, 1992 Linus Torvalds |
| * |
| * Added support for a Unix98-style ptmx device. |
| * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998 |
| * |
| */ |
| |
| #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/sched/signal.h> |
| #include <linux/string.h> |
| #include <linux/major.h> |
| #include <linux/mm.h> |
| #include <linux/init.h> |
| #include <linux/device.h> |
| #include <linux/uaccess.h> |
| #include <linux/bitops.h> |
| #include <linux/devpts_fs.h> |
| #include <linux/slab.h> |
| #include <linux/mutex.h> |
| #include <linux/poll.h> |
| #include <linux/mount.h> |
| #include <linux/file.h> |
| #include <linux/ioctl.h> |
| #include <linux/compat.h> |
| |
| #undef TTY_DEBUG_HANGUP |
| #ifdef TTY_DEBUG_HANGUP |
| # define tty_debug_hangup(tty, f, args...) tty_debug(tty, f, ##args) |
| #else |
| # define tty_debug_hangup(tty, f, args...) do {} while (0) |
| #endif |
| |
| #ifdef CONFIG_UNIX98_PTYS |
| static struct tty_driver *ptm_driver; |
| static struct tty_driver *pts_driver; |
| static DEFINE_MUTEX(devpts_mutex); |
| #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_io_error(tty)) |
| return; |
| if (tty->count > 2) |
| return; |
| } |
| set_bit(TTY_IO_ERROR, &tty->flags); |
| wake_up_interruptible(&tty->read_wait); |
| wake_up_interruptible(&tty->write_wait); |
| spin_lock_irq(&tty->ctrl_lock); |
| tty->packet = 0; |
| spin_unlock_irq(&tty->ctrl_lock); |
| /* Review - krefs on tty_link ?? */ |
| if (!tty->link) |
| return; |
| 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) { |
| mutex_lock(&devpts_mutex); |
| if (tty->link->driver_data) |
| devpts_pty_kill(tty->link->driver_data); |
| mutex_unlock(&devpts_mutex); |
| } |
| #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) |
| { |
| tty_wakeup(tty->link); |
| set_bit(TTY_THROTTLED, &tty->flags); |
| } |
| |
| /** |
| * pty_write - write to a pty |
| * @tty: the tty we write from |
| * @buf: kernel buffer of data |
| * @count: bytes to write |
| * |
| * 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 c) |
| { |
| struct tty_struct *to = tty->link; |
| |
| if (tty->stopped || !c) |
| return 0; |
| |
| return tty_insert_flip_string_and_push_buffer(to->port, buf, 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) |
| { |
| if (tty->stopped) |
| return 0; |
| return tty_buffer_space_avail(tty->link->port); |
| } |
| |
| /** |
| * pty_chars_in_buffer - characters currently in our tx queue |
| * @tty: our tty |
| * |
| * 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) |
| { |
| return 0; |
| } |
| |
| /* 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 int pty_get_lock(struct tty_struct *tty, int __user *arg) |
| { |
| int locked = test_bit(TTY_PTY_LOCK, &tty->flags); |
| return put_user(locked, arg); |
| } |
| |
| /* Set the packet mode on a pty */ |
| static int pty_set_pktmode(struct tty_struct *tty, int __user *arg) |
| { |
| int pktmode; |
| |
| if (get_user(pktmode, arg)) |
| return -EFAULT; |
| |
| spin_lock_irq(&tty->ctrl_lock); |
| if (pktmode) { |
| if (!tty->packet) { |
| tty->link->ctrl_status = 0; |
| smp_mb(); |
| tty->packet = 1; |
| } |
| } else |
| tty->packet = 0; |
| spin_unlock_irq(&tty->ctrl_lock); |
| |
| return 0; |
| } |
| |
| /* Get the packet mode of a pty */ |
| static int pty_get_pktmode(struct tty_struct *tty, int __user *arg) |
| { |
| int pktmode = tty->packet; |
| return put_user(pktmode, arg); |
| } |
| |
| /* Send a signal to the slave */ |
| static int pty_signal(struct tty_struct *tty, int sig) |
| { |
| struct pid *pgrp; |
| |
| if (sig != SIGINT && sig != SIGQUIT && sig != SIGTSTP) |
| return -EINVAL; |
| |
| if (tty->link) { |
| pgrp = tty_get_pgrp(tty->link); |
| if (pgrp) |
| kill_pgrp(pgrp, sig, 1); |
| put_pid(pgrp); |
| } |
| return 0; |
| } |
| |
| static void pty_flush_buffer(struct tty_struct *tty) |
| { |
| struct tty_struct *to = tty->link; |
| |
| if (!to) |
| return; |
| |
| tty_buffer_flush(to, NULL); |
| if (to->packet) { |
| spin_lock_irq(&tty->ctrl_lock); |
| tty->ctrl_status |= TIOCPKT_FLUSHWRITE; |
| wake_up_interruptible(&to->read_wait); |
| spin_unlock_irq(&tty->ctrl_lock); |
| } |
| } |
| |
| static int pty_open(struct tty_struct *tty, struct file *filp) |
| { |
| if (!tty || !tty->link) |
| return -ENODEV; |
| |
| if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) |
| goto out; |
| if (test_bit(TTY_PTY_LOCK, &tty->link->flags)) |
| goto out; |
| if (tty->driver->subtype == PTY_TYPE_SLAVE && tty->link->count != 1) |
| goto out; |
| |
| clear_bit(TTY_IO_ERROR, &tty->flags); |
| clear_bit(TTY_OTHER_CLOSED, &tty->link->flags); |
| set_bit(TTY_THROTTLED, &tty->flags); |
| return 0; |
| |
| out: |
| set_bit(TTY_IO_ERROR, &tty->flags); |
| return -EIO; |
| } |
| |
| static void pty_set_termios(struct tty_struct *tty, |
| struct ktermios *old_termios) |
| { |
| /* See if packet mode change of state. */ |
| if (tty->link && tty->link->packet) { |
| int extproc = (old_termios->c_lflag & EXTPROC) | L_EXTPROC(tty); |
| int old_flow = ((old_termios->c_iflag & IXON) && |
| (old_termios->c_cc[VSTOP] == '\023') && |
| (old_termios->c_cc[VSTART] == '\021')); |
| int new_flow = (I_IXON(tty) && |
| STOP_CHAR(tty) == '\023' && |
| START_CHAR(tty) == '\021'); |
| if ((old_flow != new_flow) || extproc) { |
| spin_lock_irq(&tty->ctrl_lock); |
| if (old_flow != new_flow) { |
| tty->ctrl_status &= ~(TIOCPKT_DOSTOP | TIOCPKT_NOSTOP); |
| if (new_flow) |
| tty->ctrl_status |= TIOCPKT_DOSTOP; |
| else |
| tty->ctrl_status |= TIOCPKT_NOSTOP; |
| } |
| if (extproc) |
| tty->ctrl_status |= TIOCPKT_IOCTL; |
| spin_unlock_irq(&tty->ctrl_lock); |
| wake_up_interruptible(&tty->link->read_wait); |
| } |
| } |
| |
| tty->termios.c_cflag &= ~(CSIZE | PARENB); |
| 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 |
| */ |
| |
| static int pty_resize(struct tty_struct *tty, struct winsize *ws) |
| { |
| struct pid *pgrp, *rpgrp; |
| struct tty_struct *pty = tty->link; |
| |
| /* For a PTY we need to lock the tty side */ |
| mutex_lock(&tty->winsize_mutex); |
| if (!memcmp(ws, &tty->winsize, sizeof(*ws))) |
| goto done; |
| |
| /* Signal the foreground process group of both ptys */ |
| pgrp = tty_get_pgrp(tty); |
| rpgrp = tty_get_pgrp(pty); |
| |
| 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->winsize_mutex); |
| return 0; |
| } |
| |
| /** |
| * pty_start - start() handler |
| * pty_stop - stop() handler |
| * @tty: tty being flow-controlled |
| * |
| * Propagates the TIOCPKT status to the master pty. |
| * |
| * NB: only the master pty can be in packet mode so only the slave |
| * needs start()/stop() handlers |
| */ |
| static void pty_start(struct tty_struct *tty) |
| { |
| unsigned long flags; |
| |
| if (tty->link && tty->link->packet) { |
| spin_lock_irqsave(&tty->ctrl_lock, flags); |
| tty->ctrl_status &= ~TIOCPKT_STOP; |
| tty->ctrl_status |= TIOCPKT_START; |
| spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
| wake_up_interruptible_poll(&tty->link->read_wait, EPOLLIN); |
| } |
| } |
| |
| static void pty_stop(struct tty_struct *tty) |
| { |
| unsigned long flags; |
| |
| if (tty->link && tty->link->packet) { |
| spin_lock_irqsave(&tty->ctrl_lock, flags); |
| tty->ctrl_status &= ~TIOCPKT_START; |
| tty->ctrl_status |= TIOCPKT_STOP; |
| spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
| wake_up_interruptible_poll(&tty->link->read_wait, EPOLLIN); |
| } |
| } |
| |
| /** |
| * pty_common_install - set up the pty pair |
| * @driver: the pty driver |
| * @tty: the tty being instantiated |
| * @legacy: true if this is BSD style |
| * |
| * Perform the initial set up for the tty/pty pair. Called from the |
| * tty layer when the port is first opened. |
| * |
| * Locking: the caller must hold the tty_mutex |
| */ |
| static int pty_common_install(struct tty_driver *driver, struct tty_struct *tty, |
| bool legacy) |
| { |
| struct tty_struct *o_tty; |
| struct tty_port *ports[2]; |
| int idx = tty->index; |
| int retval = -ENOMEM; |
| |
| /* Opening the slave first has always returned -EIO */ |
| if (driver->subtype != PTY_TYPE_MASTER) |
| return -EIO; |
| |
| ports[0] = kmalloc(sizeof **ports, GFP_KERNEL); |
| ports[1] = kmalloc(sizeof **ports, GFP_KERNEL); |
| if (!ports[0] || !ports[1]) |
| goto err; |
| if (!try_module_get(driver->other->owner)) { |
| /* This cannot in fact currently happen */ |
| goto err; |
| } |
| o_tty = alloc_tty_struct(driver->other, idx); |
| if (!o_tty) |
| goto err_put_module; |
| |
| tty_set_lock_subclass(o_tty); |
| lockdep_set_subclass(&o_tty->termios_rwsem, TTY_LOCK_SLAVE); |
| |
| if (legacy) { |
| /* We always use new tty termios data so we can do this |
| the easy way .. */ |
| tty_init_termios(tty); |
| tty_init_termios(o_tty); |
| |
| driver->other->ttys[idx] = o_tty; |
| driver->ttys[idx] = tty; |
| } else { |
| memset(&tty->termios_locked, 0, sizeof(tty->termios_locked)); |
| tty->termios = driver->init_termios; |
| memset(&o_tty->termios_locked, 0, sizeof(tty->termios_locked)); |
| o_tty->termios = driver->other->init_termios; |
| } |
| |
| /* |
| * Everything allocated ... set up the o_tty structure. |
| */ |
| tty_driver_kref_get(driver->other); |
| /* Establish the links in both directions */ |
| tty->link = o_tty; |
| o_tty->link = tty; |
| tty_port_init(ports[0]); |
| tty_port_init(ports[1]); |
| tty_buffer_set_limit(ports[0], 8192); |
| tty_buffer_set_limit(ports[1], 8192); |
| o_tty->port = ports[0]; |
| tty->port = ports[1]; |
| o_tty->port->itty = o_tty; |
| |
| tty_buffer_set_lock_subclass(o_tty->port); |
| |
| tty_driver_kref_get(driver); |
| tty->count++; |
| o_tty->count++; |
| return 0; |
| |
| err_put_module: |
| module_put(driver->other->owner); |
| err: |
| kfree(ports[0]); |
| kfree(ports[1]); |
| return retval; |
| } |
| |
| static void pty_cleanup(struct tty_struct *tty) |
| { |
| tty_port_put(tty->port); |
| } |
| |
| /* Traditional BSD devices */ |
| #ifdef CONFIG_LEGACY_PTYS |
| |
| static int pty_install(struct tty_driver *driver, struct tty_struct *tty) |
| { |
| return pty_common_install(driver, tty, true); |
| } |
| |
| static void pty_remove(struct tty_driver *driver, struct tty_struct *tty) |
| { |
| struct tty_struct *pair = tty->link; |
| driver->ttys[tty->index] = NULL; |
| if (pair) |
| pair->driver->ttys[pair->index] = NULL; |
| } |
| |
| static int pty_bsd_ioctl(struct tty_struct *tty, |
| 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 TIOCGPTLCK: /* Get PT Lock status */ |
| return pty_get_lock(tty, (int __user *)arg); |
| case TIOCPKT: /* Set PT packet mode */ |
| return pty_set_pktmode(tty, (int __user *)arg); |
| case TIOCGPKT: /* Get PT packet mode */ |
| return pty_get_pktmode(tty, (int __user *)arg); |
| case TIOCSIG: /* Send signal to other side of pty */ |
| return pty_signal(tty, (int) arg); |
| case TIOCGPTN: /* TTY returns ENOTTY, but glibc expects EINVAL here */ |
| return -EINVAL; |
| } |
| return -ENOIOCTLCMD; |
| } |
| |
| #ifdef CONFIG_COMPAT |
| static long pty_bsd_compat_ioctl(struct tty_struct *tty, |
| unsigned int cmd, unsigned long arg) |
| { |
| /* |
| * PTY ioctls don't require any special translation between 32-bit and |
| * 64-bit userspace, they are already compatible. |
| */ |
| return pty_bsd_ioctl(tty, cmd, (unsigned long)compat_ptr(arg)); |
| } |
| #else |
| #define pty_bsd_compat_ioctl NULL |
| #endif |
| |
| static int legacy_count = CONFIG_LEGACY_PTY_COUNT; |
| /* |
| * not really modular, but the easiest way to keep compat with existing |
| * bootargs behaviour is to continue using module_param here. |
| */ |
| module_param(legacy_count, int, 0); |
| |
| /* |
| * 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, |
| .write_room = pty_write_room, |
| .flush_buffer = pty_flush_buffer, |
| .chars_in_buffer = pty_chars_in_buffer, |
| .unthrottle = pty_unthrottle, |
| .ioctl = pty_bsd_ioctl, |
| .compat_ioctl = pty_bsd_compat_ioctl, |
| .cleanup = pty_cleanup, |
| .resize = pty_resize, |
| .remove = pty_remove |
| }; |
| |
| 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, |
| .cleanup = pty_cleanup, |
| .resize = pty_resize, |
| .start = pty_start, |
| .stop = pty_stop, |
| .remove = pty_remove |
| }; |
| |
| static void __init legacy_pty_init(void) |
| { |
| struct tty_driver *pty_driver, *pty_slave_driver; |
| |
| if (legacy_count <= 0) |
| return; |
| |
| pty_driver = tty_alloc_driver(legacy_count, |
| TTY_DRIVER_RESET_TERMIOS | |
| TTY_DRIVER_REAL_RAW | |
| TTY_DRIVER_DYNAMIC_ALLOC); |
| if (IS_ERR(pty_driver)) |
| panic("Couldn't allocate pty driver"); |
| |
| pty_slave_driver = tty_alloc_driver(legacy_count, |
| TTY_DRIVER_RESET_TERMIOS | |
| TTY_DRIVER_REAL_RAW | |
| TTY_DRIVER_DYNAMIC_ALLOC); |
| if (IS_ERR(pty_slave_driver)) |
| panic("Couldn't allocate pty slave driver"); |
| |
| 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->other = pty_slave_driver; |
| tty_set_operations(pty_driver, &master_pty_ops_bsd); |
| |
| 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->other = pty_driver; |
| tty_set_operations(pty_slave_driver, &slave_pty_ops_bsd); |
| |
| 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 |
| static struct cdev ptmx_cdev; |
| |
| /** |
| * ptm_open_peer - open the peer of a pty |
| * @master: the open struct file of the ptmx device node |
| * @tty: the master of the pty being opened |
| * @flags: the flags for open |
| * |
| * Provide a race free way for userspace to open the slave end of a pty |
| * (where they have the master fd and cannot access or trust the mount |
| * namespace /dev/pts was mounted inside). |
| */ |
| int ptm_open_peer(struct file *master, struct tty_struct *tty, int flags) |
| { |
| int fd = -1; |
| struct file *filp; |
| int retval = -EINVAL; |
| struct path path; |
| |
| if (tty->driver != ptm_driver) |
| return -EIO; |
| |
| fd = get_unused_fd_flags(flags); |
| if (fd < 0) { |
| retval = fd; |
| goto err; |
| } |
| |
| /* Compute the slave's path */ |
| path.mnt = devpts_mntget(master, tty->driver_data); |
| if (IS_ERR(path.mnt)) { |
| retval = PTR_ERR(path.mnt); |
| goto err_put; |
| } |
| path.dentry = tty->link->driver_data; |
| |
| filp = dentry_open(&path, flags, current_cred()); |
| mntput(path.mnt); |
| if (IS_ERR(filp)) { |
| retval = PTR_ERR(filp); |
| goto err_put; |
| } |
| |
| fd_install(fd, filp); |
| return fd; |
| |
| err_put: |
| put_unused_fd(fd); |
| err: |
| return retval; |
| } |
| |
| static int pty_unix98_ioctl(struct tty_struct *tty, |
| 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 TIOCGPTLCK: /* Get PT Lock status */ |
| return pty_get_lock(tty, (int __user *)arg); |
| case TIOCPKT: /* Set PT packet mode */ |
| return pty_set_pktmode(tty, (int __user *)arg); |
| case TIOCGPKT: /* Get PT packet mode */ |
| return pty_get_pktmode(tty, (int __user *)arg); |
| case TIOCGPTN: /* Get PT Number */ |
| return put_user(tty->index, (unsigned int __user *)arg); |
| case TIOCSIG: /* Send signal to other side of pty */ |
| return pty_signal(tty, (int) arg); |
| } |
| |
| return -ENOIOCTLCMD; |
| } |
| |
| #ifdef CONFIG_COMPAT |
| static long pty_unix98_compat_ioctl(struct tty_struct *tty, |
| unsigned int cmd, unsigned long arg) |
| { |
| /* |
| * PTY ioctls don't require any special translation between 32-bit and |
| * 64-bit userspace, they are already compatible. |
| */ |
| return pty_unix98_ioctl(tty, cmd, |
| cmd == TIOCSIG ? arg : (unsigned long)compat_ptr(arg)); |
| } |
| #else |
| #define pty_unix98_compat_ioctl NULL |
| #endif |
| |
| /** |
| * 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 file *file, int idx) |
| { |
| /* Master must be open via /dev/ptmx */ |
| return ERR_PTR(-EIO); |
| } |
| |
| /** |
| * 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 for the tty pointer. |
| */ |
| |
| static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver, |
| struct file *file, int idx) |
| { |
| struct tty_struct *tty; |
| |
| mutex_lock(&devpts_mutex); |
| tty = devpts_get_priv(file->f_path.dentry); |
| mutex_unlock(&devpts_mutex); |
| /* Master must be open before slave */ |
| if (!tty) |
| return ERR_PTR(-EIO); |
| return tty; |
| } |
| |
| static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty) |
| { |
| return pty_common_install(driver, tty, false); |
| } |
| |
| /* this is called once with whichever end is closed last */ |
| static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty) |
| { |
| struct pts_fs_info *fsi; |
| |
| if (tty->driver->subtype == PTY_TYPE_MASTER) |
| fsi = tty->driver_data; |
| else |
| fsi = tty->link->driver_data; |
| |
| if (fsi) { |
| devpts_kill_index(fsi, tty->index); |
| devpts_release(fsi); |
| } |
| } |
| |
| static void pty_show_fdinfo(struct tty_struct *tty, struct seq_file *m) |
| { |
| seq_printf(m, "tty-index:\t%d\n", tty->index); |
| } |
| |
| 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, |
| .ioctl = pty_unix98_ioctl, |
| .compat_ioctl = pty_unix98_compat_ioctl, |
| .resize = pty_resize, |
| .cleanup = pty_cleanup, |
| .show_fdinfo = pty_show_fdinfo, |
| }; |
| |
| 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, |
| .start = pty_start, |
| .stop = pty_stop, |
| .cleanup = pty_cleanup, |
| }; |
| |
| /** |
| * 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 pts_fs_info *fsi; |
| struct tty_struct *tty; |
| struct dentry *dentry; |
| int retval; |
| int index; |
| |
| nonseekable_open(inode, filp); |
| |
| /* We refuse fsnotify events on ptmx, since it's a shared resource */ |
| filp->f_mode |= FMODE_NONOTIFY; |
| |
| retval = tty_alloc_file(filp); |
| if (retval) |
| return retval; |
| |
| fsi = devpts_acquire(filp); |
| if (IS_ERR(fsi)) { |
| retval = PTR_ERR(fsi); |
| goto out_free_file; |
| } |
| |
| /* find a device that is not in use. */ |
| mutex_lock(&devpts_mutex); |
| index = devpts_new_index(fsi); |
| mutex_unlock(&devpts_mutex); |
| |
| retval = index; |
| if (index < 0) |
| goto out_put_fsi; |
| |
| |
| mutex_lock(&tty_mutex); |
| tty = tty_init_dev(ptm_driver, index); |
| /* The tty returned here is locked so we can safely |
| drop the mutex */ |
| mutex_unlock(&tty_mutex); |
| |
| retval = PTR_ERR(tty); |
| if (IS_ERR(tty)) |
| goto out; |
| |
| /* |
| * From here on out, the tty is "live", and the index and |
| * fsi will be killed/put by the tty_release() |
| */ |
| set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */ |
| tty->driver_data = fsi; |
| |
| tty_add_file(tty, filp); |
| |
| dentry = devpts_pty_new(fsi, index, tty->link); |
| if (IS_ERR(dentry)) { |
| retval = PTR_ERR(dentry); |
| goto err_release; |
| } |
| tty->link->driver_data = dentry; |
| |
| retval = ptm_driver->ops->open(tty, filp); |
| if (retval) |
| goto err_release; |
| |
| tty_debug_hangup(tty, "opening (count=%d)\n", tty->count); |
| |
| tty_unlock(tty); |
| return 0; |
| err_release: |
| tty_unlock(tty); |
| // This will also put-ref the fsi |
| tty_release(inode, filp); |
| return retval; |
| out: |
| devpts_kill_index(fsi, index); |
| out_put_fsi: |
| devpts_release(fsi); |
| out_free_file: |
| tty_free_file(filp); |
| return retval; |
| } |
| |
| static struct file_operations ptmx_fops __ro_after_init; |
| |
| static void __init unix98_pty_init(void) |
| { |
| ptm_driver = tty_alloc_driver(NR_UNIX98_PTY_MAX, |
| TTY_DRIVER_RESET_TERMIOS | |
| TTY_DRIVER_REAL_RAW | |
| TTY_DRIVER_DYNAMIC_DEV | |
| TTY_DRIVER_DEVPTS_MEM | |
| TTY_DRIVER_DYNAMIC_ALLOC); |
| if (IS_ERR(ptm_driver)) |
| panic("Couldn't allocate Unix98 ptm driver"); |
| pts_driver = tty_alloc_driver(NR_UNIX98_PTY_MAX, |
| TTY_DRIVER_RESET_TERMIOS | |
| TTY_DRIVER_REAL_RAW | |
| TTY_DRIVER_DYNAMIC_DEV | |
| TTY_DRIVER_DEVPTS_MEM | |
| TTY_DRIVER_DYNAMIC_ALLOC); |
| if (IS_ERR(pts_driver)) |
| panic("Couldn't allocate Unix98 pts driver"); |
| |
| 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->other = pts_driver; |
| tty_set_operations(ptm_driver, &ptm_unix98_ops); |
| |
| 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->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"); |
| |
| /* 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"); |
| 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; |
| } |
| device_initcall(pty_init); |