3168 lines
77 KiB
C
3168 lines
77 KiB
C
/*
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* Copyright (C) 1991, 1992 Linus Torvalds
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*/
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/*
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* 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles
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* or rs-channels. It also implements echoing, cooked mode etc.
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*
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* Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0.
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*
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* Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the
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* tty_struct and tty_queue structures. Previously there was an array
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* of 256 tty_struct's which was statically allocated, and the
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* tty_queue structures were allocated at boot time. Both are now
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* dynamically allocated only when the tty is open.
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*
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* Also restructured routines so that there is more of a separation
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* between the high-level tty routines (tty_io.c and tty_ioctl.c) and
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* the low-level tty routines (serial.c, pty.c, console.c). This
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* makes for cleaner and more compact code. -TYT, 9/17/92
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*
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* Modified by Fred N. van Kempen, 01/29/93, to add line disciplines
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* which can be dynamically activated and de-activated by the line
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* discipline handling modules (like SLIP).
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*
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* NOTE: pay no attention to the line discipline code (yet); its
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* interface is still subject to change in this version...
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* -- TYT, 1/31/92
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*
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* Added functionality to the OPOST tty handling. No delays, but all
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* other bits should be there.
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* -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993.
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*
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* Rewrote canonical mode and added more termios flags.
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* -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94
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*
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* Reorganized FASYNC support so mouse code can share it.
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* -- ctm@ardi.com, 9Sep95
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*
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* New TIOCLINUX variants added.
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* -- mj@k332.feld.cvut.cz, 19-Nov-95
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*
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* Restrict vt switching via ioctl()
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* -- grif@cs.ucr.edu, 5-Dec-95
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*
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* Move console and virtual terminal code to more appropriate files,
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* implement CONFIG_VT and generalize console device interface.
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* -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97
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*
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* Rewrote tty_init_dev and tty_release_dev to eliminate races.
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* -- Bill Hawes <whawes@star.net>, June 97
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*
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* Added devfs support.
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* -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998
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*
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* Added support for a Unix98-style ptmx device.
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* -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
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*
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* Reduced memory usage for older ARM systems
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* -- Russell King <rmk@arm.linux.org.uk>
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*
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* Move do_SAK() into process context. Less stack use in devfs functions.
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* alloc_tty_struct() always uses kmalloc()
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* -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01
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*/
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#include <linux/types.h>
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#include <linux/major.h>
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#include <linux/errno.h>
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#include <linux/signal.h>
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#include <linux/fcntl.h>
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#include <linux/sched/signal.h>
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#include <linux/sched/task.h>
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#include <linux/interrupt.h>
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#include <linux/tty.h>
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#include <linux/tty_driver.h>
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#include <linux/tty_flip.h>
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#include <linux/devpts_fs.h>
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#include <linux/file.h>
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#include <linux/fdtable.h>
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#include <linux/console.h>
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#include <linux/timer.h>
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#include <linux/ctype.h>
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#include <linux/kd.h>
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#include <linux/mm.h>
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#include <linux/string.h>
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#include <linux/slab.h>
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#include <linux/poll.h>
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#include <linux/proc_fs.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/device.h>
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#include <linux/wait.h>
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#include <linux/bitops.h>
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#include <linux/delay.h>
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#include <linux/seq_file.h>
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#include <linux/serial.h>
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#include <linux/ratelimit.h>
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#include <linux/uaccess.h>
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#include <linux/kbd_kern.h>
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#include <linux/vt_kern.h>
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#include <linux/selection.h>
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#include <linux/kmod.h>
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#include <linux/nsproxy.h>
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#undef TTY_DEBUG_HANGUP
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#ifdef TTY_DEBUG_HANGUP
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# define tty_debug_hangup(tty, f, args...) tty_debug(tty, f, ##args)
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#else
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# define tty_debug_hangup(tty, f, args...) do { } while (0)
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#endif
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#define TTY_PARANOIA_CHECK 1
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#define CHECK_TTY_COUNT 1
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struct ktermios tty_std_termios = { /* for the benefit of tty drivers */
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.c_iflag = ICRNL | IXON,
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.c_oflag = OPOST | ONLCR,
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.c_cflag = B38400 | CS8 | CREAD | HUPCL,
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.c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
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ECHOCTL | ECHOKE | IEXTEN,
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.c_cc = INIT_C_CC,
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.c_ispeed = 38400,
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.c_ospeed = 38400,
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/* .c_line = N_TTY, */
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};
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EXPORT_SYMBOL(tty_std_termios);
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/* This list gets poked at by procfs and various bits of boot up code. This
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could do with some rationalisation such as pulling the tty proc function
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into this file */
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LIST_HEAD(tty_drivers); /* linked list of tty drivers */
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/* Mutex to protect creating and releasing a tty */
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DEFINE_MUTEX(tty_mutex);
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static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
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static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *);
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ssize_t redirected_tty_write(struct file *, const char __user *,
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size_t, loff_t *);
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static unsigned int tty_poll(struct file *, poll_table *);
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static int tty_open(struct inode *, struct file *);
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long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
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#ifdef CONFIG_COMPAT
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static long tty_compat_ioctl(struct file *file, unsigned int cmd,
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unsigned long arg);
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#else
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#define tty_compat_ioctl NULL
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#endif
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static int __tty_fasync(int fd, struct file *filp, int on);
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static int tty_fasync(int fd, struct file *filp, int on);
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static void release_tty(struct tty_struct *tty, int idx);
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/**
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* free_tty_struct - free a disused tty
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* @tty: tty struct to free
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*
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* Free the write buffers, tty queue and tty memory itself.
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*
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* Locking: none. Must be called after tty is definitely unused
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*/
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static void free_tty_struct(struct tty_struct *tty)
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{
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tty_ldisc_deinit(tty);
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put_device(tty->dev);
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kfree(tty->write_buf);
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tty->magic = 0xDEADDEAD;
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kfree(tty);
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}
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static inline struct tty_struct *file_tty(struct file *file)
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{
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return ((struct tty_file_private *)file->private_data)->tty;
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}
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int tty_alloc_file(struct file *file)
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{
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struct tty_file_private *priv;
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priv = kmalloc(sizeof(*priv), GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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file->private_data = priv;
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return 0;
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}
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/* Associate a new file with the tty structure */
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void tty_add_file(struct tty_struct *tty, struct file *file)
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{
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struct tty_file_private *priv = file->private_data;
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priv->tty = tty;
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priv->file = file;
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spin_lock(&tty->files_lock);
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list_add(&priv->list, &tty->tty_files);
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spin_unlock(&tty->files_lock);
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}
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/**
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* tty_free_file - free file->private_data
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*
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* This shall be used only for fail path handling when tty_add_file was not
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* called yet.
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*/
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void tty_free_file(struct file *file)
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{
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struct tty_file_private *priv = file->private_data;
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file->private_data = NULL;
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kfree(priv);
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}
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/* Delete file from its tty */
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static void tty_del_file(struct file *file)
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{
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struct tty_file_private *priv = file->private_data;
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struct tty_struct *tty = priv->tty;
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spin_lock(&tty->files_lock);
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list_del(&priv->list);
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spin_unlock(&tty->files_lock);
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tty_free_file(file);
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}
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/**
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* tty_name - return tty naming
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* @tty: tty structure
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*
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* Convert a tty structure into a name. The name reflects the kernel
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* naming policy and if udev is in use may not reflect user space
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*
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* Locking: none
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*/
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const char *tty_name(const struct tty_struct *tty)
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{
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if (!tty) /* Hmm. NULL pointer. That's fun. */
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return "NULL tty";
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return tty->name;
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}
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EXPORT_SYMBOL(tty_name);
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const char *tty_driver_name(const struct tty_struct *tty)
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{
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if (!tty || !tty->driver)
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return "";
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return tty->driver->name;
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}
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static int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
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const char *routine)
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{
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#ifdef TTY_PARANOIA_CHECK
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if (!tty) {
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pr_warn("(%d:%d): %s: NULL tty\n",
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imajor(inode), iminor(inode), routine);
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return 1;
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}
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if (tty->magic != TTY_MAGIC) {
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pr_warn("(%d:%d): %s: bad magic number\n",
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imajor(inode), iminor(inode), routine);
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return 1;
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}
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#endif
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return 0;
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}
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/* Caller must hold tty_lock */
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static int check_tty_count(struct tty_struct *tty, const char *routine)
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{
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#ifdef CHECK_TTY_COUNT
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struct list_head *p;
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int count = 0;
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spin_lock(&tty->files_lock);
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list_for_each(p, &tty->tty_files) {
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count++;
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}
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spin_unlock(&tty->files_lock);
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if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
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tty->driver->subtype == PTY_TYPE_SLAVE &&
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tty->link && tty->link->count)
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count++;
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if (tty->count != count) {
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tty_warn(tty, "%s: tty->count(%d) != #fd's(%d)\n",
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routine, tty->count, count);
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return count;
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}
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#endif
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return 0;
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}
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/**
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* get_tty_driver - find device of a tty
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* @dev_t: device identifier
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* @index: returns the index of the tty
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*
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* This routine returns a tty driver structure, given a device number
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* and also passes back the index number.
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*
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* Locking: caller must hold tty_mutex
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*/
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static struct tty_driver *get_tty_driver(dev_t device, int *index)
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{
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struct tty_driver *p;
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list_for_each_entry(p, &tty_drivers, tty_drivers) {
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dev_t base = MKDEV(p->major, p->minor_start);
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if (device < base || device >= base + p->num)
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continue;
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*index = device - base;
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return tty_driver_kref_get(p);
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}
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return NULL;
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}
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#ifdef CONFIG_CONSOLE_POLL
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/**
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* tty_find_polling_driver - find device of a polled tty
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* @name: name string to match
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* @line: pointer to resulting tty line nr
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*
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* This routine returns a tty driver structure, given a name
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* and the condition that the tty driver is capable of polled
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* operation.
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*/
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struct tty_driver *tty_find_polling_driver(char *name, int *line)
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{
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struct tty_driver *p, *res = NULL;
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int tty_line = 0;
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int len;
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char *str, *stp;
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for (str = name; *str; str++)
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if ((*str >= '0' && *str <= '9') || *str == ',')
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break;
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if (!*str)
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return NULL;
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len = str - name;
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tty_line = simple_strtoul(str, &str, 10);
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mutex_lock(&tty_mutex);
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/* Search through the tty devices to look for a match */
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list_for_each_entry(p, &tty_drivers, tty_drivers) {
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if (strncmp(name, p->name, len) != 0)
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continue;
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stp = str;
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if (*stp == ',')
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stp++;
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if (*stp == '\0')
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stp = NULL;
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if (tty_line >= 0 && tty_line < p->num && p->ops &&
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p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
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res = tty_driver_kref_get(p);
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*line = tty_line;
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break;
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}
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}
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mutex_unlock(&tty_mutex);
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return res;
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}
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EXPORT_SYMBOL_GPL(tty_find_polling_driver);
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#endif
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static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
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size_t count, loff_t *ppos)
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{
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return 0;
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}
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static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
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size_t count, loff_t *ppos)
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{
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return -EIO;
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}
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/* No kernel lock held - none needed ;) */
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static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
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{
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return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
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}
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static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
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unsigned long arg)
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{
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return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
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}
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static long hung_up_tty_compat_ioctl(struct file *file,
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unsigned int cmd, unsigned long arg)
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{
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return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
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}
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static int hung_up_tty_fasync(int fd, struct file *file, int on)
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{
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return -ENOTTY;
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}
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static const struct file_operations tty_fops = {
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.llseek = no_llseek,
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.read = tty_read,
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.write = tty_write,
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.poll = tty_poll,
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.unlocked_ioctl = tty_ioctl,
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.compat_ioctl = tty_compat_ioctl,
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.open = tty_open,
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.release = tty_release,
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.fasync = tty_fasync,
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};
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static const struct file_operations console_fops = {
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.llseek = no_llseek,
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.read = tty_read,
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.write = redirected_tty_write,
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.poll = tty_poll,
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.unlocked_ioctl = tty_ioctl,
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.compat_ioctl = tty_compat_ioctl,
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.open = tty_open,
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.release = tty_release,
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.fasync = tty_fasync,
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};
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static const struct file_operations hung_up_tty_fops = {
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.llseek = no_llseek,
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.read = hung_up_tty_read,
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.write = hung_up_tty_write,
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.poll = hung_up_tty_poll,
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.unlocked_ioctl = hung_up_tty_ioctl,
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.compat_ioctl = hung_up_tty_compat_ioctl,
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.release = tty_release,
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.fasync = hung_up_tty_fasync,
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};
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static DEFINE_SPINLOCK(redirect_lock);
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static struct file *redirect;
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/**
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* tty_wakeup - request more data
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* @tty: terminal
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*
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* Internal and external helper for wakeups of tty. This function
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* informs the line discipline if present that the driver is ready
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* to receive more output data.
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*/
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void tty_wakeup(struct tty_struct *tty)
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{
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struct tty_ldisc *ld;
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if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
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ld = tty_ldisc_ref(tty);
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if (ld) {
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if (ld->ops->write_wakeup)
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ld->ops->write_wakeup(tty);
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tty_ldisc_deref(ld);
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}
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}
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wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
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}
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EXPORT_SYMBOL_GPL(tty_wakeup);
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/**
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* __tty_hangup - actual handler for hangup events
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* @work: tty device
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*
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* This can be called by a "kworker" kernel thread. That is process
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* synchronous but doesn't hold any locks, so we need to make sure we
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* have the appropriate locks for what we're doing.
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*
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* The hangup event clears any pending redirections onto the hung up
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* device. It ensures future writes will error and it does the needed
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* line discipline hangup and signal delivery. The tty object itself
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* remains intact.
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*
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* Locking:
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* BTM
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* redirect lock for undoing redirection
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* file list lock for manipulating list of ttys
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* tty_ldiscs_lock from called functions
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* termios_rwsem resetting termios data
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* tasklist_lock to walk task list for hangup event
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* ->siglock to protect ->signal/->sighand
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*/
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static void __tty_hangup(struct tty_struct *tty, int exit_session)
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{
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struct file *cons_filp = NULL;
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struct file *filp, *f = NULL;
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struct tty_file_private *priv;
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int closecount = 0, n;
|
|
int refs;
|
|
|
|
if (!tty)
|
|
return;
|
|
|
|
|
|
spin_lock(&redirect_lock);
|
|
if (redirect && file_tty(redirect) == tty) {
|
|
f = redirect;
|
|
redirect = NULL;
|
|
}
|
|
spin_unlock(&redirect_lock);
|
|
|
|
tty_lock(tty);
|
|
|
|
if (test_bit(TTY_HUPPED, &tty->flags)) {
|
|
tty_unlock(tty);
|
|
return;
|
|
}
|
|
|
|
/* inuse_filps is protected by the single tty lock,
|
|
this really needs to change if we want to flush the
|
|
workqueue with the lock held */
|
|
check_tty_count(tty, "tty_hangup");
|
|
|
|
spin_lock(&tty->files_lock);
|
|
/* This breaks for file handles being sent over AF_UNIX sockets ? */
|
|
list_for_each_entry(priv, &tty->tty_files, list) {
|
|
filp = priv->file;
|
|
if (filp->f_op->write == redirected_tty_write)
|
|
cons_filp = filp;
|
|
if (filp->f_op->write != tty_write)
|
|
continue;
|
|
closecount++;
|
|
__tty_fasync(-1, filp, 0); /* can't block */
|
|
filp->f_op = &hung_up_tty_fops;
|
|
}
|
|
spin_unlock(&tty->files_lock);
|
|
|
|
refs = tty_signal_session_leader(tty, exit_session);
|
|
/* Account for the p->signal references we killed */
|
|
while (refs--)
|
|
tty_kref_put(tty);
|
|
|
|
tty_ldisc_hangup(tty, cons_filp != NULL);
|
|
|
|
spin_lock_irq(&tty->ctrl_lock);
|
|
clear_bit(TTY_THROTTLED, &tty->flags);
|
|
clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
|
|
put_pid(tty->session);
|
|
put_pid(tty->pgrp);
|
|
tty->session = NULL;
|
|
tty->pgrp = NULL;
|
|
tty->ctrl_status = 0;
|
|
spin_unlock_irq(&tty->ctrl_lock);
|
|
|
|
/*
|
|
* If one of the devices matches a console pointer, we
|
|
* cannot just call hangup() because that will cause
|
|
* tty->count and state->count to go out of sync.
|
|
* So we just call close() the right number of times.
|
|
*/
|
|
if (cons_filp) {
|
|
if (tty->ops->close)
|
|
for (n = 0; n < closecount; n++)
|
|
tty->ops->close(tty, cons_filp);
|
|
} else if (tty->ops->hangup)
|
|
tty->ops->hangup(tty);
|
|
/*
|
|
* We don't want to have driver/ldisc interactions beyond the ones
|
|
* we did here. The driver layer expects no calls after ->hangup()
|
|
* from the ldisc side, which is now guaranteed.
|
|
*/
|
|
set_bit(TTY_HUPPED, &tty->flags);
|
|
tty_unlock(tty);
|
|
|
|
if (f)
|
|
fput(f);
|
|
}
|
|
|
|
static void do_tty_hangup(struct work_struct *work)
|
|
{
|
|
struct tty_struct *tty =
|
|
container_of(work, struct tty_struct, hangup_work);
|
|
|
|
__tty_hangup(tty, 0);
|
|
}
|
|
|
|
/**
|
|
* tty_hangup - trigger a hangup event
|
|
* @tty: tty to hangup
|
|
*
|
|
* A carrier loss (virtual or otherwise) has occurred on this like
|
|
* schedule a hangup sequence to run after this event.
|
|
*/
|
|
|
|
void tty_hangup(struct tty_struct *tty)
|
|
{
|
|
tty_debug_hangup(tty, "hangup\n");
|
|
schedule_work(&tty->hangup_work);
|
|
}
|
|
|
|
EXPORT_SYMBOL(tty_hangup);
|
|
|
|
/**
|
|
* tty_vhangup - process vhangup
|
|
* @tty: tty to hangup
|
|
*
|
|
* The user has asked via system call for the terminal to be hung up.
|
|
* We do this synchronously so that when the syscall returns the process
|
|
* is complete. That guarantee is necessary for security reasons.
|
|
*/
|
|
|
|
void tty_vhangup(struct tty_struct *tty)
|
|
{
|
|
tty_debug_hangup(tty, "vhangup\n");
|
|
__tty_hangup(tty, 0);
|
|
}
|
|
|
|
EXPORT_SYMBOL(tty_vhangup);
|
|
|
|
|
|
/**
|
|
* tty_vhangup_self - process vhangup for own ctty
|
|
*
|
|
* Perform a vhangup on the current controlling tty
|
|
*/
|
|
|
|
void tty_vhangup_self(void)
|
|
{
|
|
struct tty_struct *tty;
|
|
|
|
tty = get_current_tty();
|
|
if (tty) {
|
|
tty_vhangup(tty);
|
|
tty_kref_put(tty);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* tty_vhangup_session - hangup session leader exit
|
|
* @tty: tty to hangup
|
|
*
|
|
* The session leader is exiting and hanging up its controlling terminal.
|
|
* Every process in the foreground process group is signalled SIGHUP.
|
|
*
|
|
* We do this synchronously so that when the syscall returns the process
|
|
* is complete. That guarantee is necessary for security reasons.
|
|
*/
|
|
|
|
void tty_vhangup_session(struct tty_struct *tty)
|
|
{
|
|
tty_debug_hangup(tty, "session hangup\n");
|
|
__tty_hangup(tty, 1);
|
|
}
|
|
|
|
/**
|
|
* tty_hung_up_p - was tty hung up
|
|
* @filp: file pointer of tty
|
|
*
|
|
* Return true if the tty has been subject to a vhangup or a carrier
|
|
* loss
|
|
*/
|
|
|
|
int tty_hung_up_p(struct file *filp)
|
|
{
|
|
return (filp && filp->f_op == &hung_up_tty_fops);
|
|
}
|
|
|
|
EXPORT_SYMBOL(tty_hung_up_p);
|
|
|
|
/**
|
|
* stop_tty - propagate flow control
|
|
* @tty: tty to stop
|
|
*
|
|
* Perform flow control to the driver. May be called
|
|
* on an already stopped device and will not re-call the driver
|
|
* method.
|
|
*
|
|
* This functionality is used by both the line disciplines for
|
|
* halting incoming flow and by the driver. It may therefore be
|
|
* called from any context, may be under the tty atomic_write_lock
|
|
* but not always.
|
|
*
|
|
* Locking:
|
|
* flow_lock
|
|
*/
|
|
|
|
void __stop_tty(struct tty_struct *tty)
|
|
{
|
|
if (tty->stopped)
|
|
return;
|
|
tty->stopped = 1;
|
|
if (tty->ops->stop)
|
|
tty->ops->stop(tty);
|
|
}
|
|
|
|
void stop_tty(struct tty_struct *tty)
|
|
{
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&tty->flow_lock, flags);
|
|
__stop_tty(tty);
|
|
spin_unlock_irqrestore(&tty->flow_lock, flags);
|
|
}
|
|
EXPORT_SYMBOL(stop_tty);
|
|
|
|
/**
|
|
* start_tty - propagate flow control
|
|
* @tty: tty to start
|
|
*
|
|
* Start a tty that has been stopped if at all possible. If this
|
|
* tty was previous stopped and is now being started, the driver
|
|
* start method is invoked and the line discipline woken.
|
|
*
|
|
* Locking:
|
|
* flow_lock
|
|
*/
|
|
|
|
void __start_tty(struct tty_struct *tty)
|
|
{
|
|
if (!tty->stopped || tty->flow_stopped)
|
|
return;
|
|
tty->stopped = 0;
|
|
if (tty->ops->start)
|
|
tty->ops->start(tty);
|
|
tty_wakeup(tty);
|
|
}
|
|
|
|
void start_tty(struct tty_struct *tty)
|
|
{
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&tty->flow_lock, flags);
|
|
__start_tty(tty);
|
|
spin_unlock_irqrestore(&tty->flow_lock, flags);
|
|
}
|
|
EXPORT_SYMBOL(start_tty);
|
|
|
|
static void tty_update_time(struct timespec *time)
|
|
{
|
|
unsigned long sec = get_seconds();
|
|
|
|
/*
|
|
* We only care if the two values differ in anything other than the
|
|
* lower three bits (i.e every 8 seconds). If so, then we can update
|
|
* the time of the tty device, otherwise it could be construded as a
|
|
* security leak to let userspace know the exact timing of the tty.
|
|
*/
|
|
if ((sec ^ time->tv_sec) & ~7)
|
|
time->tv_sec = sec;
|
|
}
|
|
|
|
/**
|
|
* tty_read - read method for tty device files
|
|
* @file: pointer to tty file
|
|
* @buf: user buffer
|
|
* @count: size of user buffer
|
|
* @ppos: unused
|
|
*
|
|
* Perform the read system call function on this terminal device. Checks
|
|
* for hung up devices before calling the line discipline method.
|
|
*
|
|
* Locking:
|
|
* Locks the line discipline internally while needed. Multiple
|
|
* read calls may be outstanding in parallel.
|
|
*/
|
|
|
|
static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
|
|
loff_t *ppos)
|
|
{
|
|
int i;
|
|
struct inode *inode = file_inode(file);
|
|
struct tty_struct *tty = file_tty(file);
|
|
struct tty_ldisc *ld;
|
|
|
|
if (tty_paranoia_check(tty, inode, "tty_read"))
|
|
return -EIO;
|
|
if (!tty || tty_io_error(tty))
|
|
return -EIO;
|
|
|
|
/* We want to wait for the line discipline to sort out in this
|
|
situation */
|
|
ld = tty_ldisc_ref_wait(tty);
|
|
if (!ld)
|
|
return hung_up_tty_read(file, buf, count, ppos);
|
|
if (ld->ops->read)
|
|
i = ld->ops->read(tty, file, buf, count);
|
|
else
|
|
i = -EIO;
|
|
tty_ldisc_deref(ld);
|
|
|
|
if (i > 0)
|
|
tty_update_time(&inode->i_atime);
|
|
|
|
return i;
|
|
}
|
|
|
|
static void tty_write_unlock(struct tty_struct *tty)
|
|
{
|
|
mutex_unlock(&tty->atomic_write_lock);
|
|
wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
|
|
}
|
|
|
|
static int tty_write_lock(struct tty_struct *tty, int ndelay)
|
|
{
|
|
if (!mutex_trylock(&tty->atomic_write_lock)) {
|
|
if (ndelay)
|
|
return -EAGAIN;
|
|
if (mutex_lock_interruptible(&tty->atomic_write_lock))
|
|
return -ERESTARTSYS;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Split writes up in sane blocksizes to avoid
|
|
* denial-of-service type attacks
|
|
*/
|
|
static inline ssize_t do_tty_write(
|
|
ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
|
|
struct tty_struct *tty,
|
|
struct file *file,
|
|
const char __user *buf,
|
|
size_t count)
|
|
{
|
|
ssize_t ret, written = 0;
|
|
unsigned int chunk;
|
|
|
|
ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
/*
|
|
* We chunk up writes into a temporary buffer. This
|
|
* simplifies low-level drivers immensely, since they
|
|
* don't have locking issues and user mode accesses.
|
|
*
|
|
* But if TTY_NO_WRITE_SPLIT is set, we should use a
|
|
* big chunk-size..
|
|
*
|
|
* The default chunk-size is 2kB, because the NTTY
|
|
* layer has problems with bigger chunks. It will
|
|
* claim to be able to handle more characters than
|
|
* it actually does.
|
|
*
|
|
* FIXME: This can probably go away now except that 64K chunks
|
|
* are too likely to fail unless switched to vmalloc...
|
|
*/
|
|
chunk = 2048;
|
|
if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
|
|
chunk = 65536;
|
|
if (count < chunk)
|
|
chunk = count;
|
|
|
|
/* write_buf/write_cnt is protected by the atomic_write_lock mutex */
|
|
if (tty->write_cnt < chunk) {
|
|
unsigned char *buf_chunk;
|
|
|
|
if (chunk < 1024)
|
|
chunk = 1024;
|
|
|
|
buf_chunk = kmalloc(chunk, GFP_KERNEL);
|
|
if (!buf_chunk) {
|
|
ret = -ENOMEM;
|
|
goto out;
|
|
}
|
|
kfree(tty->write_buf);
|
|
tty->write_cnt = chunk;
|
|
tty->write_buf = buf_chunk;
|
|
}
|
|
|
|
/* Do the write .. */
|
|
for (;;) {
|
|
size_t size = count;
|
|
if (size > chunk)
|
|
size = chunk;
|
|
ret = -EFAULT;
|
|
if (copy_from_user(tty->write_buf, buf, size))
|
|
break;
|
|
ret = write(tty, file, tty->write_buf, size);
|
|
if (ret <= 0)
|
|
break;
|
|
written += ret;
|
|
buf += ret;
|
|
count -= ret;
|
|
if (!count)
|
|
break;
|
|
ret = -ERESTARTSYS;
|
|
if (signal_pending(current))
|
|
break;
|
|
cond_resched();
|
|
}
|
|
if (written) {
|
|
tty_update_time(&file_inode(file)->i_mtime);
|
|
ret = written;
|
|
}
|
|
out:
|
|
tty_write_unlock(tty);
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* tty_write_message - write a message to a certain tty, not just the console.
|
|
* @tty: the destination tty_struct
|
|
* @msg: the message to write
|
|
*
|
|
* This is used for messages that need to be redirected to a specific tty.
|
|
* We don't put it into the syslog queue right now maybe in the future if
|
|
* really needed.
|
|
*
|
|
* We must still hold the BTM and test the CLOSING flag for the moment.
|
|
*/
|
|
|
|
void tty_write_message(struct tty_struct *tty, char *msg)
|
|
{
|
|
if (tty) {
|
|
mutex_lock(&tty->atomic_write_lock);
|
|
tty_lock(tty);
|
|
if (tty->ops->write && tty->count > 0)
|
|
tty->ops->write(tty, msg, strlen(msg));
|
|
tty_unlock(tty);
|
|
tty_write_unlock(tty);
|
|
}
|
|
return;
|
|
}
|
|
|
|
|
|
/**
|
|
* tty_write - write method for tty device file
|
|
* @file: tty file pointer
|
|
* @buf: user data to write
|
|
* @count: bytes to write
|
|
* @ppos: unused
|
|
*
|
|
* Write data to a tty device via the line discipline.
|
|
*
|
|
* Locking:
|
|
* Locks the line discipline as required
|
|
* Writes to the tty driver are serialized by the atomic_write_lock
|
|
* and are then processed in chunks to the device. The line discipline
|
|
* write method will not be invoked in parallel for each device.
|
|
*/
|
|
|
|
static ssize_t tty_write(struct file *file, const char __user *buf,
|
|
size_t count, loff_t *ppos)
|
|
{
|
|
struct tty_struct *tty = file_tty(file);
|
|
struct tty_ldisc *ld;
|
|
ssize_t ret;
|
|
|
|
if (tty_paranoia_check(tty, file_inode(file), "tty_write"))
|
|
return -EIO;
|
|
if (!tty || !tty->ops->write || tty_io_error(tty))
|
|
return -EIO;
|
|
/* Short term debug to catch buggy drivers */
|
|
if (tty->ops->write_room == NULL)
|
|
tty_err(tty, "missing write_room method\n");
|
|
ld = tty_ldisc_ref_wait(tty);
|
|
if (!ld)
|
|
return hung_up_tty_write(file, buf, count, ppos);
|
|
if (!ld->ops->write)
|
|
ret = -EIO;
|
|
else
|
|
ret = do_tty_write(ld->ops->write, tty, file, buf, count);
|
|
tty_ldisc_deref(ld);
|
|
return ret;
|
|
}
|
|
|
|
ssize_t redirected_tty_write(struct file *file, const char __user *buf,
|
|
size_t count, loff_t *ppos)
|
|
{
|
|
struct file *p = NULL;
|
|
|
|
spin_lock(&redirect_lock);
|
|
if (redirect)
|
|
p = get_file(redirect);
|
|
spin_unlock(&redirect_lock);
|
|
|
|
if (p) {
|
|
ssize_t res;
|
|
res = vfs_write(p, buf, count, &p->f_pos);
|
|
fput(p);
|
|
return res;
|
|
}
|
|
return tty_write(file, buf, count, ppos);
|
|
}
|
|
|
|
/**
|
|
* tty_send_xchar - send priority character
|
|
*
|
|
* Send a high priority character to the tty even if stopped
|
|
*
|
|
* Locking: none for xchar method, write ordering for write method.
|
|
*/
|
|
|
|
int tty_send_xchar(struct tty_struct *tty, char ch)
|
|
{
|
|
int was_stopped = tty->stopped;
|
|
|
|
if (tty->ops->send_xchar) {
|
|
down_read(&tty->termios_rwsem);
|
|
tty->ops->send_xchar(tty, ch);
|
|
up_read(&tty->termios_rwsem);
|
|
return 0;
|
|
}
|
|
|
|
if (tty_write_lock(tty, 0) < 0)
|
|
return -ERESTARTSYS;
|
|
|
|
down_read(&tty->termios_rwsem);
|
|
if (was_stopped)
|
|
start_tty(tty);
|
|
tty->ops->write(tty, &ch, 1);
|
|
if (was_stopped)
|
|
stop_tty(tty);
|
|
up_read(&tty->termios_rwsem);
|
|
tty_write_unlock(tty);
|
|
return 0;
|
|
}
|
|
|
|
static char ptychar[] = "pqrstuvwxyzabcde";
|
|
|
|
/**
|
|
* pty_line_name - generate name for a pty
|
|
* @driver: the tty driver in use
|
|
* @index: the minor number
|
|
* @p: output buffer of at least 6 bytes
|
|
*
|
|
* Generate a name from a driver reference and write it to the output
|
|
* buffer.
|
|
*
|
|
* Locking: None
|
|
*/
|
|
static void pty_line_name(struct tty_driver *driver, int index, char *p)
|
|
{
|
|
int i = index + driver->name_base;
|
|
/* ->name is initialized to "ttyp", but "tty" is expected */
|
|
sprintf(p, "%s%c%x",
|
|
driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
|
|
ptychar[i >> 4 & 0xf], i & 0xf);
|
|
}
|
|
|
|
/**
|
|
* tty_line_name - generate name for a tty
|
|
* @driver: the tty driver in use
|
|
* @index: the minor number
|
|
* @p: output buffer of at least 7 bytes
|
|
*
|
|
* Generate a name from a driver reference and write it to the output
|
|
* buffer.
|
|
*
|
|
* Locking: None
|
|
*/
|
|
static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p)
|
|
{
|
|
if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE)
|
|
return sprintf(p, "%s", driver->name);
|
|
else
|
|
return sprintf(p, "%s%d", driver->name,
|
|
index + driver->name_base);
|
|
}
|
|
|
|
/**
|
|
* tty_driver_lookup_tty() - find an existing tty, if any
|
|
* @driver: the driver for the tty
|
|
* @idx: the minor number
|
|
*
|
|
* Return the tty, if found. If not found, return NULL or ERR_PTR() if the
|
|
* driver lookup() method returns an error.
|
|
*
|
|
* Locking: tty_mutex must be held. If the tty is found, bump the tty kref.
|
|
*/
|
|
static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
|
|
struct file *file, int idx)
|
|
{
|
|
struct tty_struct *tty;
|
|
|
|
if (driver->ops->lookup)
|
|
tty = driver->ops->lookup(driver, file, idx);
|
|
else
|
|
tty = driver->ttys[idx];
|
|
|
|
if (!IS_ERR(tty))
|
|
tty_kref_get(tty);
|
|
return tty;
|
|
}
|
|
|
|
/**
|
|
* tty_init_termios - helper for termios setup
|
|
* @tty: the tty to set up
|
|
*
|
|
* Initialise the termios structures for this tty. Thus runs under
|
|
* the tty_mutex currently so we can be relaxed about ordering.
|
|
*/
|
|
|
|
void tty_init_termios(struct tty_struct *tty)
|
|
{
|
|
struct ktermios *tp;
|
|
int idx = tty->index;
|
|
|
|
if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
|
|
tty->termios = tty->driver->init_termios;
|
|
else {
|
|
/* Check for lazy saved data */
|
|
tp = tty->driver->termios[idx];
|
|
if (tp != NULL) {
|
|
tty->termios = *tp;
|
|
tty->termios.c_line = tty->driver->init_termios.c_line;
|
|
} else
|
|
tty->termios = tty->driver->init_termios;
|
|
}
|
|
/* Compatibility until drivers always set this */
|
|
tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);
|
|
tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);
|
|
}
|
|
EXPORT_SYMBOL_GPL(tty_init_termios);
|
|
|
|
int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
|
|
{
|
|
tty_init_termios(tty);
|
|
tty_driver_kref_get(driver);
|
|
tty->count++;
|
|
driver->ttys[tty->index] = tty;
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(tty_standard_install);
|
|
|
|
/**
|
|
* tty_driver_install_tty() - install a tty entry in the driver
|
|
* @driver: the driver for the tty
|
|
* @tty: the tty
|
|
*
|
|
* Install a tty object into the driver tables. The tty->index field
|
|
* will be set by the time this is called. This method is responsible
|
|
* for ensuring any need additional structures are allocated and
|
|
* configured.
|
|
*
|
|
* Locking: tty_mutex for now
|
|
*/
|
|
static int tty_driver_install_tty(struct tty_driver *driver,
|
|
struct tty_struct *tty)
|
|
{
|
|
return driver->ops->install ? driver->ops->install(driver, tty) :
|
|
tty_standard_install(driver, tty);
|
|
}
|
|
|
|
/**
|
|
* tty_driver_remove_tty() - remove a tty from the driver tables
|
|
* @driver: the driver for the tty
|
|
* @idx: the minor number
|
|
*
|
|
* Remvoe a tty object from the driver tables. The tty->index field
|
|
* will be set by the time this is called.
|
|
*
|
|
* Locking: tty_mutex for now
|
|
*/
|
|
static void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
|
|
{
|
|
if (driver->ops->remove)
|
|
driver->ops->remove(driver, tty);
|
|
else
|
|
driver->ttys[tty->index] = NULL;
|
|
}
|
|
|
|
/*
|
|
* tty_reopen() - fast re-open of an open tty
|
|
* @tty - the tty to open
|
|
*
|
|
* Return 0 on success, -errno on error.
|
|
* Re-opens on master ptys are not allowed and return -EIO.
|
|
*
|
|
* Locking: Caller must hold tty_lock
|
|
*/
|
|
static int tty_reopen(struct tty_struct *tty)
|
|
{
|
|
struct tty_driver *driver = tty->driver;
|
|
|
|
if (driver->type == TTY_DRIVER_TYPE_PTY &&
|
|
driver->subtype == PTY_TYPE_MASTER)
|
|
return -EIO;
|
|
|
|
if (!tty->count)
|
|
return -EAGAIN;
|
|
|
|
if (test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN))
|
|
return -EBUSY;
|
|
|
|
tty->count++;
|
|
|
|
if (!tty->ldisc)
|
|
return tty_ldisc_reinit(tty, tty->termios.c_line);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* tty_init_dev - initialise a tty device
|
|
* @driver: tty driver we are opening a device on
|
|
* @idx: device index
|
|
* @ret_tty: returned tty structure
|
|
*
|
|
* Prepare a tty device. This may not be a "new" clean device but
|
|
* could also be an active device. The pty drivers require special
|
|
* handling because of this.
|
|
*
|
|
* Locking:
|
|
* The function is called under the tty_mutex, which
|
|
* protects us from the tty struct or driver itself going away.
|
|
*
|
|
* On exit the tty device has the line discipline attached and
|
|
* a reference count of 1. If a pair was created for pty/tty use
|
|
* and the other was a pty master then it too has a reference count of 1.
|
|
*
|
|
* WSH 06/09/97: Rewritten to remove races and properly clean up after a
|
|
* failed open. The new code protects the open with a mutex, so it's
|
|
* really quite straightforward. The mutex locking can probably be
|
|
* relaxed for the (most common) case of reopening a tty.
|
|
*/
|
|
|
|
struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
|
|
{
|
|
struct tty_struct *tty;
|
|
int retval;
|
|
|
|
/*
|
|
* First time open is complex, especially for PTY devices.
|
|
* This code guarantees that either everything succeeds and the
|
|
* TTY is ready for operation, or else the table slots are vacated
|
|
* and the allocated memory released. (Except that the termios
|
|
* may be retained.)
|
|
*/
|
|
|
|
if (!try_module_get(driver->owner))
|
|
return ERR_PTR(-ENODEV);
|
|
|
|
tty = alloc_tty_struct(driver, idx);
|
|
if (!tty) {
|
|
retval = -ENOMEM;
|
|
goto err_module_put;
|
|
}
|
|
|
|
tty_lock(tty);
|
|
retval = tty_driver_install_tty(driver, tty);
|
|
if (retval < 0)
|
|
goto err_free_tty;
|
|
|
|
if (!tty->port)
|
|
tty->port = driver->ports[idx];
|
|
|
|
WARN_RATELIMIT(!tty->port,
|
|
"%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n",
|
|
__func__, tty->driver->name);
|
|
|
|
tty->port->itty = tty;
|
|
|
|
/*
|
|
* Structures all installed ... call the ldisc open routines.
|
|
* If we fail here just call release_tty to clean up. No need
|
|
* to decrement the use counts, as release_tty doesn't care.
|
|
*/
|
|
retval = tty_ldisc_setup(tty, tty->link);
|
|
if (retval)
|
|
goto err_release_tty;
|
|
/* Return the tty locked so that it cannot vanish under the caller */
|
|
return tty;
|
|
|
|
err_free_tty:
|
|
tty_unlock(tty);
|
|
free_tty_struct(tty);
|
|
err_module_put:
|
|
module_put(driver->owner);
|
|
return ERR_PTR(retval);
|
|
|
|
/* call the tty release_tty routine to clean out this slot */
|
|
err_release_tty:
|
|
tty_unlock(tty);
|
|
tty_info_ratelimited(tty, "ldisc open failed (%d), clearing slot %d\n",
|
|
retval, idx);
|
|
release_tty(tty, idx);
|
|
return ERR_PTR(retval);
|
|
}
|
|
|
|
static void tty_free_termios(struct tty_struct *tty)
|
|
{
|
|
struct ktermios *tp;
|
|
int idx = tty->index;
|
|
|
|
/* If the port is going to reset then it has no termios to save */
|
|
if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
|
|
return;
|
|
|
|
/* Stash the termios data */
|
|
tp = tty->driver->termios[idx];
|
|
if (tp == NULL) {
|
|
tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
|
|
if (tp == NULL)
|
|
return;
|
|
tty->driver->termios[idx] = tp;
|
|
}
|
|
*tp = tty->termios;
|
|
}
|
|
|
|
/**
|
|
* tty_flush_works - flush all works of a tty/pty pair
|
|
* @tty: tty device to flush works for (or either end of a pty pair)
|
|
*
|
|
* Sync flush all works belonging to @tty (and the 'other' tty).
|
|
*/
|
|
static void tty_flush_works(struct tty_struct *tty)
|
|
{
|
|
flush_work(&tty->SAK_work);
|
|
flush_work(&tty->hangup_work);
|
|
if (tty->link) {
|
|
flush_work(&tty->link->SAK_work);
|
|
flush_work(&tty->link->hangup_work);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* release_one_tty - release tty structure memory
|
|
* @kref: kref of tty we are obliterating
|
|
*
|
|
* Releases memory associated with a tty structure, and clears out the
|
|
* driver table slots. This function is called when a device is no longer
|
|
* in use. It also gets called when setup of a device fails.
|
|
*
|
|
* Locking:
|
|
* takes the file list lock internally when working on the list
|
|
* of ttys that the driver keeps.
|
|
*
|
|
* This method gets called from a work queue so that the driver private
|
|
* cleanup ops can sleep (needed for USB at least)
|
|
*/
|
|
static void release_one_tty(struct work_struct *work)
|
|
{
|
|
struct tty_struct *tty =
|
|
container_of(work, struct tty_struct, hangup_work);
|
|
struct tty_driver *driver = tty->driver;
|
|
struct module *owner = driver->owner;
|
|
|
|
if (tty->ops->cleanup)
|
|
tty->ops->cleanup(tty);
|
|
|
|
tty->magic = 0;
|
|
tty_driver_kref_put(driver);
|
|
module_put(owner);
|
|
|
|
spin_lock(&tty->files_lock);
|
|
list_del_init(&tty->tty_files);
|
|
spin_unlock(&tty->files_lock);
|
|
|
|
put_pid(tty->pgrp);
|
|
put_pid(tty->session);
|
|
free_tty_struct(tty);
|
|
}
|
|
|
|
static void queue_release_one_tty(struct kref *kref)
|
|
{
|
|
struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
|
|
|
|
/* The hangup queue is now free so we can reuse it rather than
|
|
waste a chunk of memory for each port */
|
|
INIT_WORK(&tty->hangup_work, release_one_tty);
|
|
schedule_work(&tty->hangup_work);
|
|
}
|
|
|
|
/**
|
|
* tty_kref_put - release a tty kref
|
|
* @tty: tty device
|
|
*
|
|
* Release a reference to a tty device and if need be let the kref
|
|
* layer destruct the object for us
|
|
*/
|
|
|
|
void tty_kref_put(struct tty_struct *tty)
|
|
{
|
|
if (tty)
|
|
kref_put(&tty->kref, queue_release_one_tty);
|
|
}
|
|
EXPORT_SYMBOL(tty_kref_put);
|
|
|
|
/**
|
|
* release_tty - release tty structure memory
|
|
*
|
|
* Release both @tty and a possible linked partner (think pty pair),
|
|
* and decrement the refcount of the backing module.
|
|
*
|
|
* Locking:
|
|
* tty_mutex
|
|
* takes the file list lock internally when working on the list
|
|
* of ttys that the driver keeps.
|
|
*
|
|
*/
|
|
static void release_tty(struct tty_struct *tty, int idx)
|
|
{
|
|
/* This should always be true but check for the moment */
|
|
WARN_ON(tty->index != idx);
|
|
WARN_ON(!mutex_is_locked(&tty_mutex));
|
|
if (tty->ops->shutdown)
|
|
tty->ops->shutdown(tty);
|
|
tty_free_termios(tty);
|
|
tty_driver_remove_tty(tty->driver, tty);
|
|
tty->port->itty = NULL;
|
|
if (tty->link)
|
|
tty->link->port->itty = NULL;
|
|
tty_buffer_cancel_work(tty->port);
|
|
|
|
tty_kref_put(tty->link);
|
|
tty_kref_put(tty);
|
|
}
|
|
|
|
/**
|
|
* tty_release_checks - check a tty before real release
|
|
* @tty: tty to check
|
|
* @o_tty: link of @tty (if any)
|
|
* @idx: index of the tty
|
|
*
|
|
* Performs some paranoid checking before true release of the @tty.
|
|
* This is a no-op unless TTY_PARANOIA_CHECK is defined.
|
|
*/
|
|
static int tty_release_checks(struct tty_struct *tty, int idx)
|
|
{
|
|
#ifdef TTY_PARANOIA_CHECK
|
|
if (idx < 0 || idx >= tty->driver->num) {
|
|
tty_debug(tty, "bad idx %d\n", idx);
|
|
return -1;
|
|
}
|
|
|
|
/* not much to check for devpts */
|
|
if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
|
|
return 0;
|
|
|
|
if (tty != tty->driver->ttys[idx]) {
|
|
tty_debug(tty, "bad driver table[%d] = %p\n",
|
|
idx, tty->driver->ttys[idx]);
|
|
return -1;
|
|
}
|
|
if (tty->driver->other) {
|
|
struct tty_struct *o_tty = tty->link;
|
|
|
|
if (o_tty != tty->driver->other->ttys[idx]) {
|
|
tty_debug(tty, "bad other table[%d] = %p\n",
|
|
idx, tty->driver->other->ttys[idx]);
|
|
return -1;
|
|
}
|
|
if (o_tty->link != tty) {
|
|
tty_debug(tty, "bad link = %p\n", o_tty->link);
|
|
return -1;
|
|
}
|
|
}
|
|
#endif
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* tty_release_struct - release a tty struct
|
|
* @tty: tty device
|
|
* @idx: index of the tty
|
|
*
|
|
* Performs the final steps to release and free a tty device. It is
|
|
* roughly the reverse of tty_init_dev.
|
|
*/
|
|
void tty_release_struct(struct tty_struct *tty, int idx)
|
|
{
|
|
/*
|
|
* Ask the line discipline code to release its structures
|
|
*/
|
|
tty_ldisc_release(tty);
|
|
|
|
/* Wait for pending work before tty destruction commmences */
|
|
tty_flush_works(tty);
|
|
|
|
tty_debug_hangup(tty, "freeing structure\n");
|
|
/*
|
|
* The release_tty function takes care of the details of clearing
|
|
* the slots and preserving the termios structure. The tty_unlock_pair
|
|
* should be safe as we keep a kref while the tty is locked (so the
|
|
* unlock never unlocks a freed tty).
|
|
*/
|
|
mutex_lock(&tty_mutex);
|
|
release_tty(tty, idx);
|
|
mutex_unlock(&tty_mutex);
|
|
}
|
|
EXPORT_SYMBOL_GPL(tty_release_struct);
|
|
|
|
/**
|
|
* tty_release - vfs callback for close
|
|
* @inode: inode of tty
|
|
* @filp: file pointer for handle to tty
|
|
*
|
|
* Called the last time each file handle is closed that references
|
|
* this tty. There may however be several such references.
|
|
*
|
|
* Locking:
|
|
* Takes bkl. See tty_release_dev
|
|
*
|
|
* Even releasing the tty structures is a tricky business.. We have
|
|
* to be very careful that the structures are all released at the
|
|
* same time, as interrupts might otherwise get the wrong pointers.
|
|
*
|
|
* WSH 09/09/97: rewritten to avoid some nasty race conditions that could
|
|
* lead to double frees or releasing memory still in use.
|
|
*/
|
|
|
|
int tty_release(struct inode *inode, struct file *filp)
|
|
{
|
|
struct tty_struct *tty = file_tty(filp);
|
|
struct tty_struct *o_tty = NULL;
|
|
int do_sleep, final;
|
|
int idx;
|
|
long timeout = 0;
|
|
int once = 1;
|
|
|
|
if (tty_paranoia_check(tty, inode, __func__))
|
|
return 0;
|
|
|
|
tty_lock(tty);
|
|
check_tty_count(tty, __func__);
|
|
|
|
__tty_fasync(-1, filp, 0);
|
|
|
|
idx = tty->index;
|
|
if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
|
|
tty->driver->subtype == PTY_TYPE_MASTER)
|
|
o_tty = tty->link;
|
|
|
|
if (tty_release_checks(tty, idx)) {
|
|
tty_unlock(tty);
|
|
return 0;
|
|
}
|
|
|
|
tty_debug_hangup(tty, "releasing (count=%d)\n", tty->count);
|
|
|
|
if (tty->ops->close)
|
|
tty->ops->close(tty, filp);
|
|
|
|
/* If tty is pty master, lock the slave pty (stable lock order) */
|
|
tty_lock_slave(o_tty);
|
|
|
|
/*
|
|
* Sanity check: if tty->count is going to zero, there shouldn't be
|
|
* any waiters on tty->read_wait or tty->write_wait. We test the
|
|
* wait queues and kick everyone out _before_ actually starting to
|
|
* close. This ensures that we won't block while releasing the tty
|
|
* structure.
|
|
*
|
|
* The test for the o_tty closing is necessary, since the master and
|
|
* slave sides may close in any order. If the slave side closes out
|
|
* first, its count will be one, since the master side holds an open.
|
|
* Thus this test wouldn't be triggered at the time the slave closed,
|
|
* so we do it now.
|
|
*/
|
|
while (1) {
|
|
do_sleep = 0;
|
|
|
|
if (tty->count <= 1) {
|
|
if (waitqueue_active(&tty->read_wait)) {
|
|
wake_up_poll(&tty->read_wait, POLLIN);
|
|
do_sleep++;
|
|
}
|
|
if (waitqueue_active(&tty->write_wait)) {
|
|
wake_up_poll(&tty->write_wait, POLLOUT);
|
|
do_sleep++;
|
|
}
|
|
}
|
|
if (o_tty && o_tty->count <= 1) {
|
|
if (waitqueue_active(&o_tty->read_wait)) {
|
|
wake_up_poll(&o_tty->read_wait, POLLIN);
|
|
do_sleep++;
|
|
}
|
|
if (waitqueue_active(&o_tty->write_wait)) {
|
|
wake_up_poll(&o_tty->write_wait, POLLOUT);
|
|
do_sleep++;
|
|
}
|
|
}
|
|
if (!do_sleep)
|
|
break;
|
|
|
|
if (once) {
|
|
once = 0;
|
|
tty_warn(tty, "read/write wait queue active!\n");
|
|
}
|
|
schedule_timeout_killable(timeout);
|
|
if (timeout < 120 * HZ)
|
|
timeout = 2 * timeout + 1;
|
|
else
|
|
timeout = MAX_SCHEDULE_TIMEOUT;
|
|
}
|
|
|
|
if (o_tty) {
|
|
if (--o_tty->count < 0) {
|
|
tty_warn(tty, "bad slave count (%d)\n", o_tty->count);
|
|
o_tty->count = 0;
|
|
}
|
|
}
|
|
if (--tty->count < 0) {
|
|
tty_warn(tty, "bad tty->count (%d)\n", tty->count);
|
|
tty->count = 0;
|
|
}
|
|
|
|
/*
|
|
* We've decremented tty->count, so we need to remove this file
|
|
* descriptor off the tty->tty_files list; this serves two
|
|
* purposes:
|
|
* - check_tty_count sees the correct number of file descriptors
|
|
* associated with this tty.
|
|
* - do_tty_hangup no longer sees this file descriptor as
|
|
* something that needs to be handled for hangups.
|
|
*/
|
|
tty_del_file(filp);
|
|
|
|
/*
|
|
* Perform some housekeeping before deciding whether to return.
|
|
*
|
|
* If _either_ side is closing, make sure there aren't any
|
|
* processes that still think tty or o_tty is their controlling
|
|
* tty.
|
|
*/
|
|
if (!tty->count) {
|
|
read_lock(&tasklist_lock);
|
|
session_clear_tty(tty->session);
|
|
if (o_tty)
|
|
session_clear_tty(o_tty->session);
|
|
read_unlock(&tasklist_lock);
|
|
}
|
|
|
|
/* check whether both sides are closing ... */
|
|
final = !tty->count && !(o_tty && o_tty->count);
|
|
|
|
tty_unlock_slave(o_tty);
|
|
tty_unlock(tty);
|
|
|
|
/* At this point, the tty->count == 0 should ensure a dead tty
|
|
cannot be re-opened by a racing opener */
|
|
|
|
if (!final)
|
|
return 0;
|
|
|
|
tty_debug_hangup(tty, "final close\n");
|
|
|
|
tty_release_struct(tty, idx);
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* tty_open_current_tty - get locked tty of current task
|
|
* @device: device number
|
|
* @filp: file pointer to tty
|
|
* @return: locked tty of the current task iff @device is /dev/tty
|
|
*
|
|
* Performs a re-open of the current task's controlling tty.
|
|
*
|
|
* We cannot return driver and index like for the other nodes because
|
|
* devpts will not work then. It expects inodes to be from devpts FS.
|
|
*/
|
|
static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
|
|
{
|
|
struct tty_struct *tty;
|
|
int retval;
|
|
|
|
if (device != MKDEV(TTYAUX_MAJOR, 0))
|
|
return NULL;
|
|
|
|
tty = get_current_tty();
|
|
if (!tty)
|
|
return ERR_PTR(-ENXIO);
|
|
|
|
filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
|
|
/* noctty = 1; */
|
|
tty_lock(tty);
|
|
tty_kref_put(tty); /* safe to drop the kref now */
|
|
|
|
retval = tty_reopen(tty);
|
|
if (retval < 0) {
|
|
tty_unlock(tty);
|
|
tty = ERR_PTR(retval);
|
|
}
|
|
return tty;
|
|
}
|
|
|
|
/**
|
|
* tty_lookup_driver - lookup a tty driver for a given device file
|
|
* @device: device number
|
|
* @filp: file pointer to tty
|
|
* @index: index for the device in the @return driver
|
|
* @return: driver for this inode (with increased refcount)
|
|
*
|
|
* If @return is not erroneous, the caller is responsible to decrement the
|
|
* refcount by tty_driver_kref_put.
|
|
*
|
|
* Locking: tty_mutex protects get_tty_driver
|
|
*/
|
|
static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
|
|
int *index)
|
|
{
|
|
struct tty_driver *driver;
|
|
|
|
switch (device) {
|
|
#ifdef CONFIG_VT
|
|
case MKDEV(TTY_MAJOR, 0): {
|
|
extern struct tty_driver *console_driver;
|
|
driver = tty_driver_kref_get(console_driver);
|
|
*index = fg_console;
|
|
break;
|
|
}
|
|
#endif
|
|
case MKDEV(TTYAUX_MAJOR, 1): {
|
|
struct tty_driver *console_driver = console_device(index);
|
|
if (console_driver) {
|
|
driver = tty_driver_kref_get(console_driver);
|
|
if (driver) {
|
|
/* Don't let /dev/console block */
|
|
filp->f_flags |= O_NONBLOCK;
|
|
break;
|
|
}
|
|
}
|
|
return ERR_PTR(-ENODEV);
|
|
}
|
|
default:
|
|
driver = get_tty_driver(device, index);
|
|
if (!driver)
|
|
return ERR_PTR(-ENODEV);
|
|
break;
|
|
}
|
|
return driver;
|
|
}
|
|
|
|
/**
|
|
* tty_open_by_driver - open a tty device
|
|
* @device: dev_t of device to open
|
|
* @inode: inode of device file
|
|
* @filp: file pointer to tty
|
|
*
|
|
* Performs the driver lookup, checks for a reopen, or otherwise
|
|
* performs the first-time tty initialization.
|
|
*
|
|
* Returns the locked initialized or re-opened &tty_struct
|
|
*
|
|
* Claims the global tty_mutex to serialize:
|
|
* - concurrent first-time tty initialization
|
|
* - concurrent tty driver removal w/ lookup
|
|
* - concurrent tty removal from driver table
|
|
*/
|
|
static struct tty_struct *tty_open_by_driver(dev_t device, struct inode *inode,
|
|
struct file *filp)
|
|
{
|
|
struct tty_struct *tty;
|
|
struct tty_driver *driver = NULL;
|
|
int index = -1;
|
|
int retval;
|
|
|
|
mutex_lock(&tty_mutex);
|
|
driver = tty_lookup_driver(device, filp, &index);
|
|
if (IS_ERR(driver)) {
|
|
mutex_unlock(&tty_mutex);
|
|
return ERR_CAST(driver);
|
|
}
|
|
|
|
/* check whether we're reopening an existing tty */
|
|
tty = tty_driver_lookup_tty(driver, filp, index);
|
|
if (IS_ERR(tty)) {
|
|
mutex_unlock(&tty_mutex);
|
|
goto out;
|
|
}
|
|
|
|
if (tty) {
|
|
mutex_unlock(&tty_mutex);
|
|
retval = tty_lock_interruptible(tty);
|
|
tty_kref_put(tty); /* drop kref from tty_driver_lookup_tty() */
|
|
if (retval) {
|
|
if (retval == -EINTR)
|
|
retval = -ERESTARTSYS;
|
|
tty = ERR_PTR(retval);
|
|
goto out;
|
|
}
|
|
retval = tty_reopen(tty);
|
|
if (retval < 0) {
|
|
tty_unlock(tty);
|
|
tty = ERR_PTR(retval);
|
|
}
|
|
} else { /* Returns with the tty_lock held for now */
|
|
tty = tty_init_dev(driver, index);
|
|
mutex_unlock(&tty_mutex);
|
|
}
|
|
out:
|
|
tty_driver_kref_put(driver);
|
|
return tty;
|
|
}
|
|
|
|
/**
|
|
* tty_open - open a tty device
|
|
* @inode: inode of device file
|
|
* @filp: file pointer to tty
|
|
*
|
|
* tty_open and tty_release keep up the tty count that contains the
|
|
* number of opens done on a tty. We cannot use the inode-count, as
|
|
* different inodes might point to the same tty.
|
|
*
|
|
* Open-counting is needed for pty masters, as well as for keeping
|
|
* track of serial lines: DTR is dropped when the last close happens.
|
|
* (This is not done solely through tty->count, now. - Ted 1/27/92)
|
|
*
|
|
* The termios state of a pty is reset on first open so that
|
|
* settings don't persist across reuse.
|
|
*
|
|
* Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
|
|
* tty->count should protect the rest.
|
|
* ->siglock protects ->signal/->sighand
|
|
*
|
|
* Note: the tty_unlock/lock cases without a ref are only safe due to
|
|
* tty_mutex
|
|
*/
|
|
|
|
static int tty_open(struct inode *inode, struct file *filp)
|
|
{
|
|
struct tty_struct *tty;
|
|
int noctty, retval;
|
|
dev_t device = inode->i_rdev;
|
|
unsigned saved_flags = filp->f_flags;
|
|
|
|
nonseekable_open(inode, filp);
|
|
|
|
retry_open:
|
|
retval = tty_alloc_file(filp);
|
|
if (retval)
|
|
return -ENOMEM;
|
|
|
|
tty = tty_open_current_tty(device, filp);
|
|
if (!tty)
|
|
tty = tty_open_by_driver(device, inode, filp);
|
|
|
|
if (IS_ERR(tty)) {
|
|
tty_free_file(filp);
|
|
retval = PTR_ERR(tty);
|
|
if (retval != -EAGAIN || signal_pending(current))
|
|
return retval;
|
|
schedule();
|
|
goto retry_open;
|
|
}
|
|
|
|
tty_add_file(tty, filp);
|
|
|
|
check_tty_count(tty, __func__);
|
|
tty_debug_hangup(tty, "opening (count=%d)\n", tty->count);
|
|
|
|
if (tty->ops->open)
|
|
retval = tty->ops->open(tty, filp);
|
|
else
|
|
retval = -ENODEV;
|
|
filp->f_flags = saved_flags;
|
|
|
|
if (retval) {
|
|
tty_debug_hangup(tty, "open error %d, releasing\n", retval);
|
|
|
|
tty_unlock(tty); /* need to call tty_release without BTM */
|
|
tty_release(inode, filp);
|
|
if (retval != -ERESTARTSYS)
|
|
return retval;
|
|
|
|
if (signal_pending(current))
|
|
return retval;
|
|
|
|
schedule();
|
|
/*
|
|
* Need to reset f_op in case a hangup happened.
|
|
*/
|
|
if (tty_hung_up_p(filp))
|
|
filp->f_op = &tty_fops;
|
|
goto retry_open;
|
|
}
|
|
clear_bit(TTY_HUPPED, &tty->flags);
|
|
|
|
noctty = (filp->f_flags & O_NOCTTY) ||
|
|
(IS_ENABLED(CONFIG_VT) && device == MKDEV(TTY_MAJOR, 0)) ||
|
|
device == MKDEV(TTYAUX_MAJOR, 1) ||
|
|
(tty->driver->type == TTY_DRIVER_TYPE_PTY &&
|
|
tty->driver->subtype == PTY_TYPE_MASTER);
|
|
if (!noctty)
|
|
tty_open_proc_set_tty(filp, tty);
|
|
tty_unlock(tty);
|
|
return 0;
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
* tty_poll - check tty status
|
|
* @filp: file being polled
|
|
* @wait: poll wait structures to update
|
|
*
|
|
* Call the line discipline polling method to obtain the poll
|
|
* status of the device.
|
|
*
|
|
* Locking: locks called line discipline but ldisc poll method
|
|
* may be re-entered freely by other callers.
|
|
*/
|
|
|
|
static unsigned int tty_poll(struct file *filp, poll_table *wait)
|
|
{
|
|
struct tty_struct *tty = file_tty(filp);
|
|
struct tty_ldisc *ld;
|
|
int ret = 0;
|
|
|
|
if (tty_paranoia_check(tty, file_inode(filp), "tty_poll"))
|
|
return 0;
|
|
|
|
ld = tty_ldisc_ref_wait(tty);
|
|
if (!ld)
|
|
return hung_up_tty_poll(filp, wait);
|
|
if (ld->ops->poll)
|
|
ret = ld->ops->poll(tty, filp, wait);
|
|
tty_ldisc_deref(ld);
|
|
return ret;
|
|
}
|
|
|
|
static int __tty_fasync(int fd, struct file *filp, int on)
|
|
{
|
|
struct tty_struct *tty = file_tty(filp);
|
|
unsigned long flags;
|
|
int retval = 0;
|
|
|
|
if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync"))
|
|
goto out;
|
|
|
|
retval = fasync_helper(fd, filp, on, &tty->fasync);
|
|
if (retval <= 0)
|
|
goto out;
|
|
|
|
if (on) {
|
|
enum pid_type type;
|
|
struct pid *pid;
|
|
|
|
spin_lock_irqsave(&tty->ctrl_lock, flags);
|
|
if (tty->pgrp) {
|
|
pid = tty->pgrp;
|
|
type = PIDTYPE_PGID;
|
|
} else {
|
|
pid = task_pid(current);
|
|
type = PIDTYPE_PID;
|
|
}
|
|
get_pid(pid);
|
|
spin_unlock_irqrestore(&tty->ctrl_lock, flags);
|
|
__f_setown(filp, pid, type, 0);
|
|
put_pid(pid);
|
|
retval = 0;
|
|
}
|
|
out:
|
|
return retval;
|
|
}
|
|
|
|
static int tty_fasync(int fd, struct file *filp, int on)
|
|
{
|
|
struct tty_struct *tty = file_tty(filp);
|
|
int retval = -ENOTTY;
|
|
|
|
tty_lock(tty);
|
|
if (!tty_hung_up_p(filp))
|
|
retval = __tty_fasync(fd, filp, on);
|
|
tty_unlock(tty);
|
|
|
|
return retval;
|
|
}
|
|
|
|
/**
|
|
* tiocsti - fake input character
|
|
* @tty: tty to fake input into
|
|
* @p: pointer to character
|
|
*
|
|
* Fake input to a tty device. Does the necessary locking and
|
|
* input management.
|
|
*
|
|
* FIXME: does not honour flow control ??
|
|
*
|
|
* Locking:
|
|
* Called functions take tty_ldiscs_lock
|
|
* current->signal->tty check is safe without locks
|
|
*
|
|
* FIXME: may race normal receive processing
|
|
*/
|
|
|
|
static int tiocsti(struct tty_struct *tty, char __user *p)
|
|
{
|
|
char ch, mbz = 0;
|
|
struct tty_ldisc *ld;
|
|
|
|
if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
|
|
return -EPERM;
|
|
if (get_user(ch, p))
|
|
return -EFAULT;
|
|
tty_audit_tiocsti(tty, ch);
|
|
ld = tty_ldisc_ref_wait(tty);
|
|
if (!ld)
|
|
return -EIO;
|
|
ld->ops->receive_buf(tty, &ch, &mbz, 1);
|
|
tty_ldisc_deref(ld);
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* tiocgwinsz - implement window query ioctl
|
|
* @tty; tty
|
|
* @arg: user buffer for result
|
|
*
|
|
* Copies the kernel idea of the window size into the user buffer.
|
|
*
|
|
* Locking: tty->winsize_mutex is taken to ensure the winsize data
|
|
* is consistent.
|
|
*/
|
|
|
|
static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
|
|
{
|
|
int err;
|
|
|
|
mutex_lock(&tty->winsize_mutex);
|
|
err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
|
|
mutex_unlock(&tty->winsize_mutex);
|
|
|
|
return err ? -EFAULT: 0;
|
|
}
|
|
|
|
/**
|
|
* tty_do_resize - resize event
|
|
* @tty: tty being resized
|
|
* @rows: rows (character)
|
|
* @cols: cols (character)
|
|
*
|
|
* Update the termios variables and send the necessary signals to
|
|
* peform a terminal resize correctly
|
|
*/
|
|
|
|
int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
|
|
{
|
|
struct pid *pgrp;
|
|
|
|
/* Lock the tty */
|
|
mutex_lock(&tty->winsize_mutex);
|
|
if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
|
|
goto done;
|
|
|
|
/* Signal the foreground process group */
|
|
pgrp = tty_get_pgrp(tty);
|
|
if (pgrp)
|
|
kill_pgrp(pgrp, SIGWINCH, 1);
|
|
put_pid(pgrp);
|
|
|
|
tty->winsize = *ws;
|
|
done:
|
|
mutex_unlock(&tty->winsize_mutex);
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(tty_do_resize);
|
|
|
|
/**
|
|
* tiocswinsz - implement window size set ioctl
|
|
* @tty; tty side of tty
|
|
* @arg: user buffer for result
|
|
*
|
|
* Copies the user idea of the window size to the kernel. Traditionally
|
|
* this is just advisory information but for the Linux console it
|
|
* actually has driver level meaning and triggers a VC resize.
|
|
*
|
|
* Locking:
|
|
* Driver dependent. The default do_resize method takes the
|
|
* tty termios mutex and ctrl_lock. The console takes its own lock
|
|
* then calls into the default method.
|
|
*/
|
|
|
|
static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
|
|
{
|
|
struct winsize tmp_ws;
|
|
if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
|
|
return -EFAULT;
|
|
|
|
if (tty->ops->resize)
|
|
return tty->ops->resize(tty, &tmp_ws);
|
|
else
|
|
return tty_do_resize(tty, &tmp_ws);
|
|
}
|
|
|
|
/**
|
|
* tioccons - allow admin to move logical console
|
|
* @file: the file to become console
|
|
*
|
|
* Allow the administrator to move the redirected console device
|
|
*
|
|
* Locking: uses redirect_lock to guard the redirect information
|
|
*/
|
|
|
|
static int tioccons(struct file *file)
|
|
{
|
|
if (!capable(CAP_SYS_ADMIN))
|
|
return -EPERM;
|
|
if (file->f_op->write == redirected_tty_write) {
|
|
struct file *f;
|
|
spin_lock(&redirect_lock);
|
|
f = redirect;
|
|
redirect = NULL;
|
|
spin_unlock(&redirect_lock);
|
|
if (f)
|
|
fput(f);
|
|
return 0;
|
|
}
|
|
spin_lock(&redirect_lock);
|
|
if (redirect) {
|
|
spin_unlock(&redirect_lock);
|
|
return -EBUSY;
|
|
}
|
|
redirect = get_file(file);
|
|
spin_unlock(&redirect_lock);
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* fionbio - non blocking ioctl
|
|
* @file: file to set blocking value
|
|
* @p: user parameter
|
|
*
|
|
* Historical tty interfaces had a blocking control ioctl before
|
|
* the generic functionality existed. This piece of history is preserved
|
|
* in the expected tty API of posix OS's.
|
|
*
|
|
* Locking: none, the open file handle ensures it won't go away.
|
|
*/
|
|
|
|
static int fionbio(struct file *file, int __user *p)
|
|
{
|
|
int nonblock;
|
|
|
|
if (get_user(nonblock, p))
|
|
return -EFAULT;
|
|
|
|
spin_lock(&file->f_lock);
|
|
if (nonblock)
|
|
file->f_flags |= O_NONBLOCK;
|
|
else
|
|
file->f_flags &= ~O_NONBLOCK;
|
|
spin_unlock(&file->f_lock);
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* tiocsetd - set line discipline
|
|
* @tty: tty device
|
|
* @p: pointer to user data
|
|
*
|
|
* Set the line discipline according to user request.
|
|
*
|
|
* Locking: see tty_set_ldisc, this function is just a helper
|
|
*/
|
|
|
|
static int tiocsetd(struct tty_struct *tty, int __user *p)
|
|
{
|
|
int disc;
|
|
int ret;
|
|
|
|
if (get_user(disc, p))
|
|
return -EFAULT;
|
|
|
|
ret = tty_set_ldisc(tty, disc);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* tiocgetd - get line discipline
|
|
* @tty: tty device
|
|
* @p: pointer to user data
|
|
*
|
|
* Retrieves the line discipline id directly from the ldisc.
|
|
*
|
|
* Locking: waits for ldisc reference (in case the line discipline
|
|
* is changing or the tty is being hungup)
|
|
*/
|
|
|
|
static int tiocgetd(struct tty_struct *tty, int __user *p)
|
|
{
|
|
struct tty_ldisc *ld;
|
|
int ret;
|
|
|
|
ld = tty_ldisc_ref_wait(tty);
|
|
if (!ld)
|
|
return -EIO;
|
|
ret = put_user(ld->ops->num, p);
|
|
tty_ldisc_deref(ld);
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* send_break - performed time break
|
|
* @tty: device to break on
|
|
* @duration: timeout in mS
|
|
*
|
|
* Perform a timed break on hardware that lacks its own driver level
|
|
* timed break functionality.
|
|
*
|
|
* Locking:
|
|
* atomic_write_lock serializes
|
|
*
|
|
*/
|
|
|
|
static int send_break(struct tty_struct *tty, unsigned int duration)
|
|
{
|
|
int retval;
|
|
|
|
if (tty->ops->break_ctl == NULL)
|
|
return 0;
|
|
|
|
if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
|
|
retval = tty->ops->break_ctl(tty, duration);
|
|
else {
|
|
/* Do the work ourselves */
|
|
if (tty_write_lock(tty, 0) < 0)
|
|
return -EINTR;
|
|
retval = tty->ops->break_ctl(tty, -1);
|
|
if (retval)
|
|
goto out;
|
|
if (!signal_pending(current))
|
|
msleep_interruptible(duration);
|
|
retval = tty->ops->break_ctl(tty, 0);
|
|
out:
|
|
tty_write_unlock(tty);
|
|
if (signal_pending(current))
|
|
retval = -EINTR;
|
|
}
|
|
return retval;
|
|
}
|
|
|
|
/**
|
|
* tty_tiocmget - get modem status
|
|
* @tty: tty device
|
|
* @file: user file pointer
|
|
* @p: pointer to result
|
|
*
|
|
* Obtain the modem status bits from the tty driver if the feature
|
|
* is supported. Return -EINVAL if it is not available.
|
|
*
|
|
* Locking: none (up to the driver)
|
|
*/
|
|
|
|
static int tty_tiocmget(struct tty_struct *tty, int __user *p)
|
|
{
|
|
int retval = -EINVAL;
|
|
|
|
if (tty->ops->tiocmget) {
|
|
retval = tty->ops->tiocmget(tty);
|
|
|
|
if (retval >= 0)
|
|
retval = put_user(retval, p);
|
|
}
|
|
return retval;
|
|
}
|
|
|
|
/**
|
|
* tty_tiocmset - set modem status
|
|
* @tty: tty device
|
|
* @cmd: command - clear bits, set bits or set all
|
|
* @p: pointer to desired bits
|
|
*
|
|
* Set the modem status bits from the tty driver if the feature
|
|
* is supported. Return -EINVAL if it is not available.
|
|
*
|
|
* Locking: none (up to the driver)
|
|
*/
|
|
|
|
static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
|
|
unsigned __user *p)
|
|
{
|
|
int retval;
|
|
unsigned int set, clear, val;
|
|
|
|
if (tty->ops->tiocmset == NULL)
|
|
return -EINVAL;
|
|
|
|
retval = get_user(val, p);
|
|
if (retval)
|
|
return retval;
|
|
set = clear = 0;
|
|
switch (cmd) {
|
|
case TIOCMBIS:
|
|
set = val;
|
|
break;
|
|
case TIOCMBIC:
|
|
clear = val;
|
|
break;
|
|
case TIOCMSET:
|
|
set = val;
|
|
clear = ~val;
|
|
break;
|
|
}
|
|
set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
|
|
clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
|
|
return tty->ops->tiocmset(tty, set, clear);
|
|
}
|
|
|
|
static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
|
|
{
|
|
int retval = -EINVAL;
|
|
struct serial_icounter_struct icount;
|
|
memset(&icount, 0, sizeof(icount));
|
|
if (tty->ops->get_icount)
|
|
retval = tty->ops->get_icount(tty, &icount);
|
|
if (retval != 0)
|
|
return retval;
|
|
if (copy_to_user(arg, &icount, sizeof(icount)))
|
|
return -EFAULT;
|
|
return 0;
|
|
}
|
|
|
|
static void tty_warn_deprecated_flags(struct serial_struct __user *ss)
|
|
{
|
|
static DEFINE_RATELIMIT_STATE(depr_flags,
|
|
DEFAULT_RATELIMIT_INTERVAL,
|
|
DEFAULT_RATELIMIT_BURST);
|
|
char comm[TASK_COMM_LEN];
|
|
int flags;
|
|
|
|
if (get_user(flags, &ss->flags))
|
|
return;
|
|
|
|
flags &= ASYNC_DEPRECATED;
|
|
|
|
if (flags && __ratelimit(&depr_flags))
|
|
pr_warn("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
|
|
__func__, get_task_comm(comm, current), flags);
|
|
}
|
|
|
|
/*
|
|
* if pty, return the slave side (real_tty)
|
|
* otherwise, return self
|
|
*/
|
|
static struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
|
|
{
|
|
if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
|
|
tty->driver->subtype == PTY_TYPE_MASTER)
|
|
tty = tty->link;
|
|
return tty;
|
|
}
|
|
|
|
/*
|
|
* Split this up, as gcc can choke on it otherwise..
|
|
*/
|
|
long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
|
|
{
|
|
struct tty_struct *tty = file_tty(file);
|
|
struct tty_struct *real_tty;
|
|
void __user *p = (void __user *)arg;
|
|
int retval;
|
|
struct tty_ldisc *ld;
|
|
|
|
if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
|
|
return -EINVAL;
|
|
|
|
real_tty = tty_pair_get_tty(tty);
|
|
|
|
/*
|
|
* Factor out some common prep work
|
|
*/
|
|
switch (cmd) {
|
|
case TIOCSETD:
|
|
case TIOCSBRK:
|
|
case TIOCCBRK:
|
|
case TCSBRK:
|
|
case TCSBRKP:
|
|
retval = tty_check_change(tty);
|
|
if (retval)
|
|
return retval;
|
|
if (cmd != TIOCCBRK) {
|
|
tty_wait_until_sent(tty, 0);
|
|
if (signal_pending(current))
|
|
return -EINTR;
|
|
}
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* Now do the stuff.
|
|
*/
|
|
switch (cmd) {
|
|
case TIOCSTI:
|
|
return tiocsti(tty, p);
|
|
case TIOCGWINSZ:
|
|
return tiocgwinsz(real_tty, p);
|
|
case TIOCSWINSZ:
|
|
return tiocswinsz(real_tty, p);
|
|
case TIOCCONS:
|
|
return real_tty != tty ? -EINVAL : tioccons(file);
|
|
case FIONBIO:
|
|
return fionbio(file, p);
|
|
case TIOCEXCL:
|
|
set_bit(TTY_EXCLUSIVE, &tty->flags);
|
|
return 0;
|
|
case TIOCNXCL:
|
|
clear_bit(TTY_EXCLUSIVE, &tty->flags);
|
|
return 0;
|
|
case TIOCGEXCL:
|
|
{
|
|
int excl = test_bit(TTY_EXCLUSIVE, &tty->flags);
|
|
return put_user(excl, (int __user *)p);
|
|
}
|
|
case TIOCGETD:
|
|
return tiocgetd(tty, p);
|
|
case TIOCSETD:
|
|
return tiocsetd(tty, p);
|
|
case TIOCVHANGUP:
|
|
if (!capable(CAP_SYS_ADMIN))
|
|
return -EPERM;
|
|
tty_vhangup(tty);
|
|
return 0;
|
|
case TIOCGDEV:
|
|
{
|
|
unsigned int ret = new_encode_dev(tty_devnum(real_tty));
|
|
return put_user(ret, (unsigned int __user *)p);
|
|
}
|
|
/*
|
|
* Break handling
|
|
*/
|
|
case TIOCSBRK: /* Turn break on, unconditionally */
|
|
if (tty->ops->break_ctl)
|
|
return tty->ops->break_ctl(tty, -1);
|
|
return 0;
|
|
case TIOCCBRK: /* Turn break off, unconditionally */
|
|
if (tty->ops->break_ctl)
|
|
return tty->ops->break_ctl(tty, 0);
|
|
return 0;
|
|
case TCSBRK: /* SVID version: non-zero arg --> no break */
|
|
/* non-zero arg means wait for all output data
|
|
* to be sent (performed above) but don't send break.
|
|
* This is used by the tcdrain() termios function.
|
|
*/
|
|
if (!arg)
|
|
return send_break(tty, 250);
|
|
return 0;
|
|
case TCSBRKP: /* support for POSIX tcsendbreak() */
|
|
return send_break(tty, arg ? arg*100 : 250);
|
|
|
|
case TIOCMGET:
|
|
return tty_tiocmget(tty, p);
|
|
case TIOCMSET:
|
|
case TIOCMBIC:
|
|
case TIOCMBIS:
|
|
return tty_tiocmset(tty, cmd, p);
|
|
case TIOCGICOUNT:
|
|
retval = tty_tiocgicount(tty, p);
|
|
/* For the moment allow fall through to the old method */
|
|
if (retval != -EINVAL)
|
|
return retval;
|
|
break;
|
|
case TCFLSH:
|
|
switch (arg) {
|
|
case TCIFLUSH:
|
|
case TCIOFLUSH:
|
|
/* flush tty buffer and allow ldisc to process ioctl */
|
|
tty_buffer_flush(tty, NULL);
|
|
break;
|
|
}
|
|
break;
|
|
case TIOCSSERIAL:
|
|
tty_warn_deprecated_flags(p);
|
|
break;
|
|
default:
|
|
retval = tty_jobctrl_ioctl(tty, real_tty, file, cmd, arg);
|
|
if (retval != -ENOIOCTLCMD)
|
|
return retval;
|
|
}
|
|
if (tty->ops->ioctl) {
|
|
retval = tty->ops->ioctl(tty, cmd, arg);
|
|
if (retval != -ENOIOCTLCMD)
|
|
return retval;
|
|
}
|
|
ld = tty_ldisc_ref_wait(tty);
|
|
if (!ld)
|
|
return hung_up_tty_ioctl(file, cmd, arg);
|
|
retval = -EINVAL;
|
|
if (ld->ops->ioctl) {
|
|
retval = ld->ops->ioctl(tty, file, cmd, arg);
|
|
if (retval == -ENOIOCTLCMD)
|
|
retval = -ENOTTY;
|
|
}
|
|
tty_ldisc_deref(ld);
|
|
return retval;
|
|
}
|
|
|
|
#ifdef CONFIG_COMPAT
|
|
static long tty_compat_ioctl(struct file *file, unsigned int cmd,
|
|
unsigned long arg)
|
|
{
|
|
struct tty_struct *tty = file_tty(file);
|
|
struct tty_ldisc *ld;
|
|
int retval = -ENOIOCTLCMD;
|
|
|
|
if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
|
|
return -EINVAL;
|
|
|
|
if (tty->ops->compat_ioctl) {
|
|
retval = tty->ops->compat_ioctl(tty, cmd, arg);
|
|
if (retval != -ENOIOCTLCMD)
|
|
return retval;
|
|
}
|
|
|
|
ld = tty_ldisc_ref_wait(tty);
|
|
if (!ld)
|
|
return hung_up_tty_compat_ioctl(file, cmd, arg);
|
|
if (ld->ops->compat_ioctl)
|
|
retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
|
|
else
|
|
retval = n_tty_compat_ioctl_helper(tty, file, cmd, arg);
|
|
tty_ldisc_deref(ld);
|
|
|
|
return retval;
|
|
}
|
|
#endif
|
|
|
|
static int this_tty(const void *t, struct file *file, unsigned fd)
|
|
{
|
|
if (likely(file->f_op->read != tty_read))
|
|
return 0;
|
|
return file_tty(file) != t ? 0 : fd + 1;
|
|
}
|
|
|
|
/*
|
|
* This implements the "Secure Attention Key" --- the idea is to
|
|
* prevent trojan horses by killing all processes associated with this
|
|
* tty when the user hits the "Secure Attention Key". Required for
|
|
* super-paranoid applications --- see the Orange Book for more details.
|
|
*
|
|
* This code could be nicer; ideally it should send a HUP, wait a few
|
|
* seconds, then send a INT, and then a KILL signal. But you then
|
|
* have to coordinate with the init process, since all processes associated
|
|
* with the current tty must be dead before the new getty is allowed
|
|
* to spawn.
|
|
*
|
|
* Now, if it would be correct ;-/ The current code has a nasty hole -
|
|
* it doesn't catch files in flight. We may send the descriptor to ourselves
|
|
* via AF_UNIX socket, close it and later fetch from socket. FIXME.
|
|
*
|
|
* Nasty bug: do_SAK is being called in interrupt context. This can
|
|
* deadlock. We punt it up to process context. AKPM - 16Mar2001
|
|
*/
|
|
void __do_SAK(struct tty_struct *tty)
|
|
{
|
|
#ifdef TTY_SOFT_SAK
|
|
tty_hangup(tty);
|
|
#else
|
|
struct task_struct *g, *p;
|
|
struct pid *session;
|
|
int i;
|
|
|
|
if (!tty)
|
|
return;
|
|
session = tty->session;
|
|
|
|
tty_ldisc_flush(tty);
|
|
|
|
tty_driver_flush_buffer(tty);
|
|
|
|
read_lock(&tasklist_lock);
|
|
/* Kill the entire session */
|
|
do_each_pid_task(session, PIDTYPE_SID, p) {
|
|
tty_notice(tty, "SAK: killed process %d (%s): by session\n",
|
|
task_pid_nr(p), p->comm);
|
|
send_sig(SIGKILL, p, 1);
|
|
} while_each_pid_task(session, PIDTYPE_SID, p);
|
|
|
|
/* Now kill any processes that happen to have the tty open */
|
|
do_each_thread(g, p) {
|
|
if (p->signal->tty == tty) {
|
|
tty_notice(tty, "SAK: killed process %d (%s): by controlling tty\n",
|
|
task_pid_nr(p), p->comm);
|
|
send_sig(SIGKILL, p, 1);
|
|
continue;
|
|
}
|
|
task_lock(p);
|
|
i = iterate_fd(p->files, 0, this_tty, tty);
|
|
if (i != 0) {
|
|
tty_notice(tty, "SAK: killed process %d (%s): by fd#%d\n",
|
|
task_pid_nr(p), p->comm, i - 1);
|
|
force_sig(SIGKILL, p);
|
|
}
|
|
task_unlock(p);
|
|
} while_each_thread(g, p);
|
|
read_unlock(&tasklist_lock);
|
|
#endif
|
|
}
|
|
|
|
static void do_SAK_work(struct work_struct *work)
|
|
{
|
|
struct tty_struct *tty =
|
|
container_of(work, struct tty_struct, SAK_work);
|
|
__do_SAK(tty);
|
|
}
|
|
|
|
/*
|
|
* The tq handling here is a little racy - tty->SAK_work may already be queued.
|
|
* Fortunately we don't need to worry, because if ->SAK_work is already queued,
|
|
* the values which we write to it will be identical to the values which it
|
|
* already has. --akpm
|
|
*/
|
|
void do_SAK(struct tty_struct *tty)
|
|
{
|
|
if (!tty)
|
|
return;
|
|
schedule_work(&tty->SAK_work);
|
|
}
|
|
|
|
EXPORT_SYMBOL(do_SAK);
|
|
|
|
static int dev_match_devt(struct device *dev, const void *data)
|
|
{
|
|
const dev_t *devt = data;
|
|
return dev->devt == *devt;
|
|
}
|
|
|
|
/* Must put_device() after it's unused! */
|
|
static struct device *tty_get_device(struct tty_struct *tty)
|
|
{
|
|
dev_t devt = tty_devnum(tty);
|
|
return class_find_device(tty_class, NULL, &devt, dev_match_devt);
|
|
}
|
|
|
|
|
|
/**
|
|
* alloc_tty_struct
|
|
*
|
|
* This subroutine allocates and initializes a tty structure.
|
|
*
|
|
* Locking: none - tty in question is not exposed at this point
|
|
*/
|
|
|
|
struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
|
|
{
|
|
struct tty_struct *tty;
|
|
|
|
tty = kzalloc(sizeof(*tty), GFP_KERNEL);
|
|
if (!tty)
|
|
return NULL;
|
|
|
|
kref_init(&tty->kref);
|
|
tty->magic = TTY_MAGIC;
|
|
tty_ldisc_init(tty);
|
|
tty->session = NULL;
|
|
tty->pgrp = NULL;
|
|
mutex_init(&tty->legacy_mutex);
|
|
mutex_init(&tty->throttle_mutex);
|
|
init_rwsem(&tty->termios_rwsem);
|
|
mutex_init(&tty->winsize_mutex);
|
|
init_ldsem(&tty->ldisc_sem);
|
|
init_waitqueue_head(&tty->write_wait);
|
|
init_waitqueue_head(&tty->read_wait);
|
|
INIT_WORK(&tty->hangup_work, do_tty_hangup);
|
|
mutex_init(&tty->atomic_write_lock);
|
|
spin_lock_init(&tty->ctrl_lock);
|
|
spin_lock_init(&tty->flow_lock);
|
|
spin_lock_init(&tty->files_lock);
|
|
INIT_LIST_HEAD(&tty->tty_files);
|
|
INIT_WORK(&tty->SAK_work, do_SAK_work);
|
|
|
|
tty->driver = driver;
|
|
tty->ops = driver->ops;
|
|
tty->index = idx;
|
|
tty_line_name(driver, idx, tty->name);
|
|
tty->dev = tty_get_device(tty);
|
|
|
|
return tty;
|
|
}
|
|
|
|
/**
|
|
* tty_put_char - write one character to a tty
|
|
* @tty: tty
|
|
* @ch: character
|
|
*
|
|
* Write one byte to the tty using the provided put_char method
|
|
* if present. Returns the number of characters successfully output.
|
|
*
|
|
* Note: the specific put_char operation in the driver layer may go
|
|
* away soon. Don't call it directly, use this method
|
|
*/
|
|
|
|
int tty_put_char(struct tty_struct *tty, unsigned char ch)
|
|
{
|
|
if (tty->ops->put_char)
|
|
return tty->ops->put_char(tty, ch);
|
|
return tty->ops->write(tty, &ch, 1);
|
|
}
|
|
EXPORT_SYMBOL_GPL(tty_put_char);
|
|
|
|
struct class *tty_class;
|
|
|
|
static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
|
|
unsigned int index, unsigned int count)
|
|
{
|
|
int err;
|
|
|
|
/* init here, since reused cdevs cause crashes */
|
|
driver->cdevs[index] = cdev_alloc();
|
|
if (!driver->cdevs[index])
|
|
return -ENOMEM;
|
|
driver->cdevs[index]->ops = &tty_fops;
|
|
driver->cdevs[index]->owner = driver->owner;
|
|
err = cdev_add(driver->cdevs[index], dev, count);
|
|
if (err)
|
|
kobject_put(&driver->cdevs[index]->kobj);
|
|
return err;
|
|
}
|
|
|
|
/**
|
|
* tty_register_device - register a tty device
|
|
* @driver: the tty driver that describes the tty device
|
|
* @index: the index in the tty driver for this tty device
|
|
* @device: a struct device that is associated with this tty device.
|
|
* This field is optional, if there is no known struct device
|
|
* for this tty device it can be set to NULL safely.
|
|
*
|
|
* Returns a pointer to the struct device for this tty device
|
|
* (or ERR_PTR(-EFOO) on error).
|
|
*
|
|
* This call is required to be made to register an individual tty device
|
|
* if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
|
|
* that bit is not set, this function should not be called by a tty
|
|
* driver.
|
|
*
|
|
* Locking: ??
|
|
*/
|
|
|
|
struct device *tty_register_device(struct tty_driver *driver, unsigned index,
|
|
struct device *device)
|
|
{
|
|
return tty_register_device_attr(driver, index, device, NULL, NULL);
|
|
}
|
|
EXPORT_SYMBOL(tty_register_device);
|
|
|
|
static void tty_device_create_release(struct device *dev)
|
|
{
|
|
dev_dbg(dev, "releasing...\n");
|
|
kfree(dev);
|
|
}
|
|
|
|
/**
|
|
* tty_register_device_attr - register a tty device
|
|
* @driver: the tty driver that describes the tty device
|
|
* @index: the index in the tty driver for this tty device
|
|
* @device: a struct device that is associated with this tty device.
|
|
* This field is optional, if there is no known struct device
|
|
* for this tty device it can be set to NULL safely.
|
|
* @drvdata: Driver data to be set to device.
|
|
* @attr_grp: Attribute group to be set on device.
|
|
*
|
|
* Returns a pointer to the struct device for this tty device
|
|
* (or ERR_PTR(-EFOO) on error).
|
|
*
|
|
* This call is required to be made to register an individual tty device
|
|
* if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
|
|
* that bit is not set, this function should not be called by a tty
|
|
* driver.
|
|
*
|
|
* Locking: ??
|
|
*/
|
|
struct device *tty_register_device_attr(struct tty_driver *driver,
|
|
unsigned index, struct device *device,
|
|
void *drvdata,
|
|
const struct attribute_group **attr_grp)
|
|
{
|
|
char name[64];
|
|
dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
|
|
struct ktermios *tp;
|
|
struct device *dev;
|
|
int retval;
|
|
|
|
if (index >= driver->num) {
|
|
pr_err("%s: Attempt to register invalid tty line number (%d)\n",
|
|
driver->name, index);
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
|
|
if (driver->type == TTY_DRIVER_TYPE_PTY)
|
|
pty_line_name(driver, index, name);
|
|
else
|
|
tty_line_name(driver, index, name);
|
|
|
|
dev = kzalloc(sizeof(*dev), GFP_KERNEL);
|
|
if (!dev)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
dev->devt = devt;
|
|
dev->class = tty_class;
|
|
dev->parent = device;
|
|
dev->release = tty_device_create_release;
|
|
dev_set_name(dev, "%s", name);
|
|
dev->groups = attr_grp;
|
|
dev_set_drvdata(dev, drvdata);
|
|
|
|
dev_set_uevent_suppress(dev, 1);
|
|
|
|
retval = device_register(dev);
|
|
if (retval)
|
|
goto err_put;
|
|
|
|
if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
|
|
/*
|
|
* Free any saved termios data so that the termios state is
|
|
* reset when reusing a minor number.
|
|
*/
|
|
tp = driver->termios[index];
|
|
if (tp) {
|
|
driver->termios[index] = NULL;
|
|
kfree(tp);
|
|
}
|
|
|
|
retval = tty_cdev_add(driver, devt, index, 1);
|
|
if (retval)
|
|
goto err_del;
|
|
}
|
|
|
|
dev_set_uevent_suppress(dev, 0);
|
|
kobject_uevent(&dev->kobj, KOBJ_ADD);
|
|
|
|
return dev;
|
|
|
|
err_del:
|
|
device_del(dev);
|
|
err_put:
|
|
put_device(dev);
|
|
|
|
return ERR_PTR(retval);
|
|
}
|
|
EXPORT_SYMBOL_GPL(tty_register_device_attr);
|
|
|
|
/**
|
|
* tty_unregister_device - unregister a tty device
|
|
* @driver: the tty driver that describes the tty device
|
|
* @index: the index in the tty driver for this tty device
|
|
*
|
|
* If a tty device is registered with a call to tty_register_device() then
|
|
* this function must be called when the tty device is gone.
|
|
*
|
|
* Locking: ??
|
|
*/
|
|
|
|
void tty_unregister_device(struct tty_driver *driver, unsigned index)
|
|
{
|
|
device_destroy(tty_class,
|
|
MKDEV(driver->major, driver->minor_start) + index);
|
|
if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
|
|
cdev_del(driver->cdevs[index]);
|
|
driver->cdevs[index] = NULL;
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(tty_unregister_device);
|
|
|
|
/**
|
|
* __tty_alloc_driver -- allocate tty driver
|
|
* @lines: count of lines this driver can handle at most
|
|
* @owner: module which is responsible for this driver
|
|
* @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
|
|
*
|
|
* This should not be called directly, some of the provided macros should be
|
|
* used instead. Use IS_ERR and friends on @retval.
|
|
*/
|
|
struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
|
|
unsigned long flags)
|
|
{
|
|
struct tty_driver *driver;
|
|
unsigned int cdevs = 1;
|
|
int err;
|
|
|
|
if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
|
|
return ERR_PTR(-EINVAL);
|
|
|
|
driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
|
|
if (!driver)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
kref_init(&driver->kref);
|
|
driver->magic = TTY_DRIVER_MAGIC;
|
|
driver->num = lines;
|
|
driver->owner = owner;
|
|
driver->flags = flags;
|
|
|
|
if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
|
|
driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
|
|
GFP_KERNEL);
|
|
driver->termios = kcalloc(lines, sizeof(*driver->termios),
|
|
GFP_KERNEL);
|
|
if (!driver->ttys || !driver->termios) {
|
|
err = -ENOMEM;
|
|
goto err_free_all;
|
|
}
|
|
}
|
|
|
|
if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
|
|
driver->ports = kcalloc(lines, sizeof(*driver->ports),
|
|
GFP_KERNEL);
|
|
if (!driver->ports) {
|
|
err = -ENOMEM;
|
|
goto err_free_all;
|
|
}
|
|
cdevs = lines;
|
|
}
|
|
|
|
driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
|
|
if (!driver->cdevs) {
|
|
err = -ENOMEM;
|
|
goto err_free_all;
|
|
}
|
|
|
|
return driver;
|
|
err_free_all:
|
|
kfree(driver->ports);
|
|
kfree(driver->ttys);
|
|
kfree(driver->termios);
|
|
kfree(driver->cdevs);
|
|
kfree(driver);
|
|
return ERR_PTR(err);
|
|
}
|
|
EXPORT_SYMBOL(__tty_alloc_driver);
|
|
|
|
static void destruct_tty_driver(struct kref *kref)
|
|
{
|
|
struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
|
|
int i;
|
|
struct ktermios *tp;
|
|
|
|
if (driver->flags & TTY_DRIVER_INSTALLED) {
|
|
for (i = 0; i < driver->num; i++) {
|
|
tp = driver->termios[i];
|
|
if (tp) {
|
|
driver->termios[i] = NULL;
|
|
kfree(tp);
|
|
}
|
|
if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
|
|
tty_unregister_device(driver, i);
|
|
}
|
|
proc_tty_unregister_driver(driver);
|
|
if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
|
|
cdev_del(driver->cdevs[0]);
|
|
}
|
|
kfree(driver->cdevs);
|
|
kfree(driver->ports);
|
|
kfree(driver->termios);
|
|
kfree(driver->ttys);
|
|
kfree(driver);
|
|
}
|
|
|
|
void tty_driver_kref_put(struct tty_driver *driver)
|
|
{
|
|
kref_put(&driver->kref, destruct_tty_driver);
|
|
}
|
|
EXPORT_SYMBOL(tty_driver_kref_put);
|
|
|
|
void tty_set_operations(struct tty_driver *driver,
|
|
const struct tty_operations *op)
|
|
{
|
|
driver->ops = op;
|
|
};
|
|
EXPORT_SYMBOL(tty_set_operations);
|
|
|
|
void put_tty_driver(struct tty_driver *d)
|
|
{
|
|
tty_driver_kref_put(d);
|
|
}
|
|
EXPORT_SYMBOL(put_tty_driver);
|
|
|
|
/*
|
|
* Called by a tty driver to register itself.
|
|
*/
|
|
int tty_register_driver(struct tty_driver *driver)
|
|
{
|
|
int error;
|
|
int i;
|
|
dev_t dev;
|
|
struct device *d;
|
|
|
|
if (!driver->major) {
|
|
error = alloc_chrdev_region(&dev, driver->minor_start,
|
|
driver->num, driver->name);
|
|
if (!error) {
|
|
driver->major = MAJOR(dev);
|
|
driver->minor_start = MINOR(dev);
|
|
}
|
|
} else {
|
|
dev = MKDEV(driver->major, driver->minor_start);
|
|
error = register_chrdev_region(dev, driver->num, driver->name);
|
|
}
|
|
if (error < 0)
|
|
goto err;
|
|
|
|
if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
|
|
error = tty_cdev_add(driver, dev, 0, driver->num);
|
|
if (error)
|
|
goto err_unreg_char;
|
|
}
|
|
|
|
mutex_lock(&tty_mutex);
|
|
list_add(&driver->tty_drivers, &tty_drivers);
|
|
mutex_unlock(&tty_mutex);
|
|
|
|
if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
|
|
for (i = 0; i < driver->num; i++) {
|
|
d = tty_register_device(driver, i, NULL);
|
|
if (IS_ERR(d)) {
|
|
error = PTR_ERR(d);
|
|
goto err_unreg_devs;
|
|
}
|
|
}
|
|
}
|
|
proc_tty_register_driver(driver);
|
|
driver->flags |= TTY_DRIVER_INSTALLED;
|
|
return 0;
|
|
|
|
err_unreg_devs:
|
|
for (i--; i >= 0; i--)
|
|
tty_unregister_device(driver, i);
|
|
|
|
mutex_lock(&tty_mutex);
|
|
list_del(&driver->tty_drivers);
|
|
mutex_unlock(&tty_mutex);
|
|
|
|
err_unreg_char:
|
|
unregister_chrdev_region(dev, driver->num);
|
|
err:
|
|
return error;
|
|
}
|
|
EXPORT_SYMBOL(tty_register_driver);
|
|
|
|
/*
|
|
* Called by a tty driver to unregister itself.
|
|
*/
|
|
int tty_unregister_driver(struct tty_driver *driver)
|
|
{
|
|
#if 0
|
|
/* FIXME */
|
|
if (driver->refcount)
|
|
return -EBUSY;
|
|
#endif
|
|
unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
|
|
driver->num);
|
|
mutex_lock(&tty_mutex);
|
|
list_del(&driver->tty_drivers);
|
|
mutex_unlock(&tty_mutex);
|
|
return 0;
|
|
}
|
|
|
|
EXPORT_SYMBOL(tty_unregister_driver);
|
|
|
|
dev_t tty_devnum(struct tty_struct *tty)
|
|
{
|
|
return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
|
|
}
|
|
EXPORT_SYMBOL(tty_devnum);
|
|
|
|
void tty_default_fops(struct file_operations *fops)
|
|
{
|
|
*fops = tty_fops;
|
|
}
|
|
|
|
static char *tty_devnode(struct device *dev, umode_t *mode)
|
|
{
|
|
if (!mode)
|
|
return NULL;
|
|
if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
|
|
dev->devt == MKDEV(TTYAUX_MAJOR, 2))
|
|
*mode = 0666;
|
|
return NULL;
|
|
}
|
|
|
|
static int __init tty_class_init(void)
|
|
{
|
|
tty_class = class_create(THIS_MODULE, "tty");
|
|
if (IS_ERR(tty_class))
|
|
return PTR_ERR(tty_class);
|
|
tty_class->devnode = tty_devnode;
|
|
return 0;
|
|
}
|
|
|
|
postcore_initcall(tty_class_init);
|
|
|
|
/* 3/2004 jmc: why do these devices exist? */
|
|
static struct cdev tty_cdev, console_cdev;
|
|
|
|
static ssize_t show_cons_active(struct device *dev,
|
|
struct device_attribute *attr, char *buf)
|
|
{
|
|
struct console *cs[16];
|
|
int i = 0;
|
|
struct console *c;
|
|
ssize_t count = 0;
|
|
|
|
console_lock();
|
|
for_each_console(c) {
|
|
if (!c->device)
|
|
continue;
|
|
if (!c->write)
|
|
continue;
|
|
if ((c->flags & CON_ENABLED) == 0)
|
|
continue;
|
|
cs[i++] = c;
|
|
if (i >= ARRAY_SIZE(cs))
|
|
break;
|
|
}
|
|
while (i--) {
|
|
int index = cs[i]->index;
|
|
struct tty_driver *drv = cs[i]->device(cs[i], &index);
|
|
|
|
/* don't resolve tty0 as some programs depend on it */
|
|
if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR))
|
|
count += tty_line_name(drv, index, buf + count);
|
|
else
|
|
count += sprintf(buf + count, "%s%d",
|
|
cs[i]->name, cs[i]->index);
|
|
|
|
count += sprintf(buf + count, "%c", i ? ' ':'\n');
|
|
}
|
|
console_unlock();
|
|
|
|
return count;
|
|
}
|
|
static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
|
|
|
|
static struct attribute *cons_dev_attrs[] = {
|
|
&dev_attr_active.attr,
|
|
NULL
|
|
};
|
|
|
|
ATTRIBUTE_GROUPS(cons_dev);
|
|
|
|
static struct device *consdev;
|
|
|
|
void console_sysfs_notify(void)
|
|
{
|
|
if (consdev)
|
|
sysfs_notify(&consdev->kobj, NULL, "active");
|
|
}
|
|
|
|
/*
|
|
* Ok, now we can initialize the rest of the tty devices and can count
|
|
* on memory allocations, interrupts etc..
|
|
*/
|
|
int __init tty_init(void)
|
|
{
|
|
cdev_init(&tty_cdev, &tty_fops);
|
|
if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
|
|
register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
|
|
panic("Couldn't register /dev/tty driver\n");
|
|
device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
|
|
|
|
cdev_init(&console_cdev, &console_fops);
|
|
if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
|
|
register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
|
|
panic("Couldn't register /dev/console driver\n");
|
|
consdev = device_create_with_groups(tty_class, NULL,
|
|
MKDEV(TTYAUX_MAJOR, 1), NULL,
|
|
cons_dev_groups, "console");
|
|
if (IS_ERR(consdev))
|
|
consdev = NULL;
|
|
|
|
#ifdef CONFIG_VT
|
|
vty_init(&console_fops);
|
|
#endif
|
|
return 0;
|
|
}
|
|
|