diff options
Diffstat (limited to 'drivers/tty/pty.c')
| -rw-r--r-- | drivers/tty/pty.c | 285 |
1 files changed, 123 insertions, 162 deletions
diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c index 284749fb0f6b..6120d827a797 100644 --- a/drivers/tty/pty.c +++ b/drivers/tty/pty.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0 /* * Copyright (C) 1991, 1992 Linus Torvalds * @@ -27,6 +28,8 @@ #include <linux/mount.h> #include <linux/file.h> #include <linux/ioctl.h> +#include <linux/compat.h> +#include "tty.h" #undef TTY_DEBUG_HANGUP #ifdef TTY_DEBUG_HANGUP @@ -43,7 +46,6 @@ static DEFINE_MUTEX(devpts_mutex); 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 { @@ -55,9 +57,8 @@ static void pty_close(struct tty_struct *tty, struct file *filp) 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); + scoped_guard(spinlock_irq, &tty->ctrl.lock) + tty->ctrl.packet = false; /* Review - krefs on tty_link ?? */ if (!tty->link) return; @@ -68,15 +69,9 @@ static void pty_close(struct tty_struct *tty, struct file *filp) 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) { - struct path *path = tty->link->driver_data; - - devpts_pty_kill(path->dentry); - path_put(path); - kfree(path); - } - mutex_unlock(&devpts_mutex); + guard(mutex)(&devpts_mutex); + if (tty->link->driver_data) + devpts_pty_kill(tty->link->driver_data); } #endif tty_vhangup(tty->link); @@ -103,7 +98,7 @@ static void pty_unthrottle(struct tty_struct *tty) * pty_write - write to a pty * @tty: the tty we write from * @buf: kernel buffer of data - * @count: bytes to write + * @c: 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 @@ -111,21 +106,14 @@ static void pty_unthrottle(struct tty_struct *tty) * the other side of the pty/tty pair. */ -static int pty_write(struct tty_struct *tty, const unsigned char *buf, int c) +static ssize_t pty_write(struct tty_struct *tty, const u8 *buf, size_t c) { struct tty_struct *to = tty->link; - if (tty->stopped) + if (tty->flow.stopped || !c) return 0; - if (c > 0) { - /* Stuff the data into the input queue of the other end */ - c = tty_insert_flip_string(to->port, buf, c); - /* And shovel */ - if (c) - tty_flip_buffer_push(to->port); - } - return c; + return tty_insert_flip_string_and_push_buffer(to->port, buf, c); } /** @@ -136,30 +124,18 @@ static int pty_write(struct tty_struct *tty, const unsigned char *buf, int c) * the other device. */ -static int pty_write_room(struct tty_struct *tty) +static unsigned int pty_write_room(struct tty_struct *tty) { - if (tty->stopped) + if (tty->flow.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) @@ -172,27 +148,30 @@ static int pty_set_lock(struct tty_struct *tty, int __user *arg) 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; + int want_pktmode; - if (get_user(pktmode, arg)) + if (get_user(want_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); + guard(spinlock_irq)(&tty->ctrl.lock); + if (!want_pktmode) { + tty->ctrl.packet = false; + return 0; + } + + if (tty->ctrl.packet) + return 0; + + tty->link->ctrl.pktstatus = 0; + smp_mb(); + tty->ctrl.packet = true; return 0; } @@ -200,7 +179,8 @@ static int pty_set_pktmode(struct tty_struct *tty, int __user *arg) /* Get the packet mode of a pty */ static int pty_get_pktmode(struct tty_struct *tty, int __user *arg) { - int pktmode = tty->packet; + int pktmode = tty->ctrl.packet; + return put_user(pktmode, arg); } @@ -229,11 +209,10 @@ static void pty_flush_buffer(struct tty_struct *tty) return; tty_buffer_flush(to, NULL); - if (to->packet) { - spin_lock_irq(&tty->ctrl_lock); - tty->ctrl_status |= TIOCPKT_FLUSHWRITE; + if (to->ctrl.packet) { + guard(spinlock_irq)(&tty->ctrl.lock); + tty->ctrl.pktstatus |= TIOCPKT_FLUSHWRITE; wake_up_interruptible(&to->read_wait); - spin_unlock_irq(&tty->ctrl_lock); } } @@ -260,10 +239,10 @@ out: } static void pty_set_termios(struct tty_struct *tty, - struct ktermios *old_termios) + const struct ktermios *old_termios) { /* See if packet mode change of state. */ - if (tty->link && tty->link->packet) { + if (tty->link && tty->link->ctrl.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') && @@ -272,17 +251,17 @@ static void pty_set_termios(struct tty_struct *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; + scoped_guard(spinlock_irq, &tty->ctrl.lock) { + if (old_flow != new_flow) { + tty->ctrl.pktstatus &= ~(TIOCPKT_DOSTOP | TIOCPKT_NOSTOP); + if (new_flow) + tty->ctrl.pktstatus |= TIOCPKT_DOSTOP; + else + tty->ctrl.pktstatus |= TIOCPKT_NOSTOP; + } + if (extproc) + tty->ctrl.pktstatus |= TIOCPKT_IOCTL; } - if (extproc) - tty->ctrl_status |= TIOCPKT_IOCTL; - spin_unlock_irq(&tty->ctrl_lock); wake_up_interruptible(&tty->link->read_wait); } } @@ -292,7 +271,7 @@ static void pty_set_termios(struct tty_struct *tty, } /** - * pty_do_resize - resize event + * pty_resize - resize event * @tty: tty being resized * @ws: window size being set. * @@ -306,9 +285,9 @@ static int pty_resize(struct tty_struct *tty, struct winsize *ws) struct tty_struct *pty = tty->link; /* For a PTY we need to lock the tty side */ - mutex_lock(&tty->winsize_mutex); + guard(mutex)(&tty->winsize_mutex); if (!memcmp(ws, &tty->winsize, sizeof(*ws))) - goto done; + return 0; /* Signal the foreground process group of both ptys */ pgrp = tty_get_pgrp(tty); @@ -324,8 +303,7 @@ static int pty_resize(struct tty_struct *tty, struct winsize *ws) tty->winsize = *ws; pty->winsize = *ws; /* Never used so will go away soon */ -done: - mutex_unlock(&tty->winsize_mutex); + return 0; } @@ -341,28 +319,26 @@ done: */ static void pty_start(struct tty_struct *tty) { - unsigned long flags; + if (!tty->link || !tty->link->ctrl.packet) + return; - 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, POLLIN); + scoped_guard(spinlock_irqsave, &tty->ctrl.lock) { + tty->ctrl.pktstatus &= ~TIOCPKT_STOP; + tty->ctrl.pktstatus |= TIOCPKT_START; } + 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->ctrl.packet) + return; - 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, POLLIN); + scoped_guard(spinlock_irqsave, &tty->ctrl.lock) { + tty->ctrl.pktstatus &= ~TIOCPKT_START; + tty->ctrl.pktstatus |= TIOCPKT_STOP; } + wake_up_interruptible_poll(&tty->link->read_wait, EPOLLIN); } /** @@ -464,6 +440,7 @@ static int pty_install(struct tty_driver *driver, struct tty_struct *tty) 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; @@ -489,6 +466,7 @@ static int pty_bsd_ioctl(struct tty_struct *tty, return -ENOIOCTLCMD; } +#ifdef CONFIG_COMPAT static long pty_bsd_compat_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg) { @@ -496,8 +474,11 @@ static long pty_bsd_compat_ioctl(struct tty_struct *tty, * 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, arg); + 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; /* @@ -517,7 +498,6 @@ static const struct tty_operations master_pty_ops_bsd = { .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, @@ -533,7 +513,6 @@ static const struct tty_operations slave_pty_ops_bsd = { .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, @@ -606,46 +585,39 @@ static inline void legacy_pty_init(void) { } #ifdef CONFIG_UNIX98_PTYS static struct cdev ptmx_cdev; -/** - * pty_open_peer - open the peer of a pty - * @tty: the peer of the pty being opened - * - * Open the cached dentry in tty->link, providing a safe way for userspace - * to get 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). - */ -static struct file *pty_open_peer(struct tty_struct *tty, int flags) +static struct file *ptm_open_peer_file(struct file *master, + struct tty_struct *tty, int flags) { - if (tty->driver->subtype != PTY_TYPE_MASTER) - return ERR_PTR(-EIO); - return dentry_open(tty->link->driver_data, flags, current_cred()); -} + struct path path; + struct file *file; -static int pty_get_peer(struct tty_struct *tty, int flags) -{ - int fd = -1; - struct file *filp = NULL; - int retval = -EINVAL; - - fd = get_unused_fd_flags(0); - 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)) + return ERR_CAST(path.mnt); + path.dentry = tty->link->driver_data; - filp = pty_open_peer(tty, flags); - if (IS_ERR(filp)) { - retval = PTR_ERR(filp); - goto err_put; - } + file = dentry_open(&path, flags, current_cred()); + mntput(path.mnt); + return file; +} - fd_install(fd, filp); - return fd; +/** + * 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) +{ + if (tty->driver != ptm_driver) + return -EIO; -err_put: - put_unused_fd(fd); -err: - return retval; + return FD_ADD(flags, ptm_open_peer_file(master, tty, flags)); } static int pty_unix98_ioctl(struct tty_struct *tty, @@ -662,8 +634,6 @@ static int pty_unix98_ioctl(struct tty_struct *tty, return pty_get_pktmode(tty, (int __user *)arg); case TIOCGPTN: /* Get PT Number */ return put_user(tty->index, (unsigned int __user *)arg); - case TIOCGPTPEER: /* Open the other end */ - return pty_get_peer(tty, (int) arg); case TIOCSIG: /* Send signal to other side of pty */ return pty_signal(tty, (int) arg); } @@ -671,6 +641,7 @@ static int pty_unix98_ioctl(struct tty_struct *tty, return -ENOIOCTLCMD; } +#ifdef CONFIG_COMPAT static long pty_unix98_compat_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg) { @@ -678,12 +649,17 @@ static long pty_unix98_compat_ioctl(struct tty_struct *tty, * 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, arg); + 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 + * @file: unused * @idx: tty index * * Look up a pty master device. Called under the tty_mutex for now. @@ -700,6 +676,7 @@ static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver, /** * pts_unix98_lookup - find a pty slave * @driver: pts driver + * @file: file pointer to tty * @idx: tty index * * Look up a pty master device. Called under the tty_mutex for now. @@ -709,15 +686,9 @@ static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver, 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); + guard(mutex)(&devpts_mutex); /* Master must be open before slave */ - if (!tty) - return ERR_PTR(-EIO); - return tty; + return devpts_get_priv(file->f_path.dentry) ? : ERR_PTR(-EIO); } static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty) @@ -741,6 +712,11 @@ static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty) } } +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, @@ -750,12 +726,12 @@ static const struct tty_operations ptm_unix98_ops = { .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 + .cleanup = pty_cleanup, + .show_fdinfo = pty_show_fdinfo, }; static const struct tty_operations pty_unix98_ops = { @@ -767,7 +743,6 @@ static const struct tty_operations pty_unix98_ops = { .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, @@ -791,7 +766,6 @@ static int ptmx_open(struct inode *inode, struct file *filp) { struct pts_fs_info *fsi; struct tty_struct *tty; - struct path *pts_path; struct dentry *dentry; int retval; int index; @@ -799,7 +773,7 @@ static int ptmx_open(struct inode *inode, struct file *filp) nonseekable_open(inode, filp); /* We refuse fsnotify events on ptmx, since it's a shared resource */ - filp->f_mode |= FMODE_NONOTIFY; + file_set_fsnotify_mode(filp, FMODE_NONOTIFY); retval = tty_alloc_file(filp); if (retval) @@ -812,20 +786,17 @@ static int ptmx_open(struct inode *inode, struct file *filp) } /* find a device that is not in use. */ - mutex_lock(&devpts_mutex); - index = devpts_new_index(fsi); - mutex_unlock(&devpts_mutex); + scoped_guard(mutex, &devpts_mutex) + index = devpts_new_index(fsi); 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); + /* The tty returned here is locked so we can safely drop the mutex */ + scoped_guard(mutex, &tty_mutex) + tty = tty_init_dev(ptm_driver, index); retval = PTR_ERR(tty); if (IS_ERR(tty)) @@ -845,26 +816,16 @@ static int ptmx_open(struct inode *inode, struct file *filp) retval = PTR_ERR(dentry); goto err_release; } - /* We need to cache a fake path for TIOCGPTPEER. */ - pts_path = kmalloc(sizeof(struct path), GFP_KERNEL); - if (!pts_path) - goto err_release; - pts_path->mnt = filp->f_path.mnt; - pts_path->dentry = dentry; - path_get(pts_path); - tty->link->driver_data = pts_path; + tty->link->driver_data = dentry; retval = ptm_driver->ops->open(tty, filp); if (retval) - goto err_path_put; + goto err_release; tty_debug_hangup(tty, "opening (count=%d)\n", tty->count); tty_unlock(tty); return 0; -err_path_put: - path_put(pts_path); - kfree(pts_path); err_release: tty_unlock(tty); // This will also put-ref the fsi @@ -942,7 +903,7 @@ static void __init unix98_pty_init(void) 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"); + device_create(&tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx"); } #else |