diff options
Diffstat (limited to 'drivers/char/tty_io.c')
| -rw-r--r-- | drivers/char/tty_io.c | 2980 |
1 files changed, 2980 insertions, 0 deletions
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c new file mode 100644 index 00000000000..06e5a3f1836 --- /dev/null +++ b/drivers/char/tty_io.c @@ -0,0 +1,2980 @@ +/* + * linux/drivers/char/tty_io.c + * + * Copyright (C) 1991, 1992 Linus Torvalds + */ + +/* + * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles + * or rs-channels. It also implements echoing, cooked mode etc. + * + * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0. + * + * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the + * tty_struct and tty_queue structures. Previously there was an array + * of 256 tty_struct's which was statically allocated, and the + * tty_queue structures were allocated at boot time. Both are now + * dynamically allocated only when the tty is open. + * + * Also restructured routines so that there is more of a separation + * between the high-level tty routines (tty_io.c and tty_ioctl.c) and + * the low-level tty routines (serial.c, pty.c, console.c). This + * makes for cleaner and more compact code. -TYT, 9/17/92 + * + * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines + * which can be dynamically activated and de-activated by the line + * discipline handling modules (like SLIP). + * + * NOTE: pay no attention to the line discipline code (yet); its + * interface is still subject to change in this version... + * -- TYT, 1/31/92 + * + * Added functionality to the OPOST tty handling. No delays, but all + * other bits should be there. + * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993. + * + * Rewrote canonical mode and added more termios flags. + * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94 + * + * Reorganized FASYNC support so mouse code can share it. + * -- ctm@ardi.com, 9Sep95 + * + * New TIOCLINUX variants added. + * -- mj@k332.feld.cvut.cz, 19-Nov-95 + * + * Restrict vt switching via ioctl() + * -- grif@cs.ucr.edu, 5-Dec-95 + * + * Move console and virtual terminal code to more appropriate files, + * implement CONFIG_VT and generalize console device interface. + * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97 + * + * Rewrote init_dev and release_dev to eliminate races. + * -- Bill Hawes <whawes@star.net>, June 97 + * + * Added devfs support. + * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998 + * + * Added support for a Unix98-style ptmx device. + * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998 + * + * Reduced memory usage for older ARM systems + * -- Russell King <rmk@arm.linux.org.uk> + * + * Move do_SAK() into process context. Less stack use in devfs functions. + * alloc_tty_struct() always uses kmalloc() -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01 + */ + +#include <linux/config.h> +#include <linux/types.h> +#include <linux/major.h> +#include <linux/errno.h> +#include <linux/signal.h> +#include <linux/fcntl.h> +#include <linux/sched.h> +#include <linux/interrupt.h> +#include <linux/tty.h> +#include <linux/tty_driver.h> +#include <linux/tty_flip.h> +#include <linux/devpts_fs.h> +#include <linux/file.h> +#include <linux/console.h> +#include <linux/timer.h> +#include <linux/ctype.h> +#include <linux/kd.h> +#include <linux/mm.h> +#include <linux/string.h> +#include <linux/slab.h> +#include <linux/poll.h> +#include <linux/proc_fs.h> +#include <linux/init.h> +#include <linux/module.h> +#include <linux/smp_lock.h> +#include <linux/device.h> +#include <linux/idr.h> +#include <linux/wait.h> +#include <linux/bitops.h> + +#include <asm/uaccess.h> +#include <asm/system.h> + +#include <linux/kbd_kern.h> +#include <linux/vt_kern.h> +#include <linux/selection.h> +#include <linux/devfs_fs_kernel.h> + +#include <linux/kmod.h> + +#undef TTY_DEBUG_HANGUP + +#define TTY_PARANOIA_CHECK 1 +#define CHECK_TTY_COUNT 1 + +struct termios tty_std_termios = { /* for the benefit of tty drivers */ + .c_iflag = ICRNL | IXON, + .c_oflag = OPOST | ONLCR, + .c_cflag = B38400 | CS8 | CREAD | HUPCL, + .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK | + ECHOCTL | ECHOKE | IEXTEN, + .c_cc = INIT_C_CC +}; + +EXPORT_SYMBOL(tty_std_termios); + +/* This list gets poked at by procfs and various bits of boot up code. This + could do with some rationalisation such as pulling the tty proc function + into this file */ + +LIST_HEAD(tty_drivers); /* linked list of tty drivers */ + +/* Semaphore to protect creating and releasing a tty. This is shared with + vt.c for deeply disgusting hack reasons */ +DECLARE_MUTEX(tty_sem); + +#ifdef CONFIG_UNIX98_PTYS +extern struct tty_driver *ptm_driver; /* Unix98 pty masters; for /dev/ptmx */ +extern int pty_limit; /* Config limit on Unix98 ptys */ +static DEFINE_IDR(allocated_ptys); +static DECLARE_MUTEX(allocated_ptys_lock); +static int ptmx_open(struct inode *, struct file *); +#endif + +extern void disable_early_printk(void); + +static void initialize_tty_struct(struct tty_struct *tty); + +static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *); +static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *); +ssize_t redirected_tty_write(struct file *, const char __user *, size_t, loff_t *); +static unsigned int tty_poll(struct file *, poll_table *); +static int tty_open(struct inode *, struct file *); +static int tty_release(struct inode *, struct file *); +int tty_ioctl(struct inode * inode, struct file * file, + unsigned int cmd, unsigned long arg); +static int tty_fasync(int fd, struct file * filp, int on); +extern void rs_360_init(void); +static void release_mem(struct tty_struct *tty, int idx); + + +static struct tty_struct *alloc_tty_struct(void) +{ + struct tty_struct *tty; + + tty = kmalloc(sizeof(struct tty_struct), GFP_KERNEL); + if (tty) + memset(tty, 0, sizeof(struct tty_struct)); + return tty; +} + +static inline void free_tty_struct(struct tty_struct *tty) +{ + kfree(tty->write_buf); + kfree(tty); +} + +#define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base) + +char *tty_name(struct tty_struct *tty, char *buf) +{ + if (!tty) /* Hmm. NULL pointer. That's fun. */ + strcpy(buf, "NULL tty"); + else + strcpy(buf, tty->name); + return buf; +} + +EXPORT_SYMBOL(tty_name); + +inline int tty_paranoia_check(struct tty_struct *tty, struct inode *inode, + const char *routine) +{ +#ifdef TTY_PARANOIA_CHECK + if (!tty) { + printk(KERN_WARNING + "null TTY for (%d:%d) in %s\n", + imajor(inode), iminor(inode), routine); + return 1; + } + if (tty->magic != TTY_MAGIC) { + printk(KERN_WARNING + "bad magic number for tty struct (%d:%d) in %s\n", + imajor(inode), iminor(inode), routine); + return 1; + } +#endif + return 0; +} + +static int check_tty_count(struct tty_struct *tty, const char *routine) +{ +#ifdef CHECK_TTY_COUNT + struct list_head *p; + int count = 0; + + file_list_lock(); + list_for_each(p, &tty->tty_files) { + count++; + } + file_list_unlock(); + if (tty->driver->type == TTY_DRIVER_TYPE_PTY && + tty->driver->subtype == PTY_TYPE_SLAVE && + tty->link && tty->link->count) + count++; + if (tty->count != count) { + printk(KERN_WARNING "Warning: dev (%s) tty->count(%d) " + "!= #fd's(%d) in %s\n", + tty->name, tty->count, count, routine); + return count; + } +#endif + return 0; +} + +/* + * This is probably overkill for real world processors but + * they are not on hot paths so a little discipline won't do + * any harm. + */ + +static void tty_set_termios_ldisc(struct tty_struct *tty, int num) +{ + down(&tty->termios_sem); + tty->termios->c_line = num; + up(&tty->termios_sem); +} + +/* + * This guards the refcounted line discipline lists. The lock + * must be taken with irqs off because there are hangup path + * callers who will do ldisc lookups and cannot sleep. + */ + +static DEFINE_SPINLOCK(tty_ldisc_lock); +static DECLARE_WAIT_QUEUE_HEAD(tty_ldisc_wait); +static struct tty_ldisc tty_ldiscs[NR_LDISCS]; /* line disc dispatch table */ + +int tty_register_ldisc(int disc, struct tty_ldisc *new_ldisc) +{ + unsigned long flags; + int ret = 0; + + if (disc < N_TTY || disc >= NR_LDISCS) + return -EINVAL; + + spin_lock_irqsave(&tty_ldisc_lock, flags); + if (new_ldisc) { + tty_ldiscs[disc] = *new_ldisc; + tty_ldiscs[disc].num = disc; + tty_ldiscs[disc].flags |= LDISC_FLAG_DEFINED; + tty_ldiscs[disc].refcount = 0; + } else { + if(tty_ldiscs[disc].refcount) + ret = -EBUSY; + else + tty_ldiscs[disc].flags &= ~LDISC_FLAG_DEFINED; + } + spin_unlock_irqrestore(&tty_ldisc_lock, flags); + + return ret; +} + +EXPORT_SYMBOL(tty_register_ldisc); + +struct tty_ldisc *tty_ldisc_get(int disc) +{ + unsigned long flags; + struct tty_ldisc *ld; + + if (disc < N_TTY || disc >= NR_LDISCS) + return NULL; + + spin_lock_irqsave(&tty_ldisc_lock, flags); + + ld = &tty_ldiscs[disc]; + /* Check the entry is defined */ + if(ld->flags & LDISC_FLAG_DEFINED) + { + /* If the module is being unloaded we can't use it */ + if (!try_module_get(ld->owner)) + ld = NULL; + else /* lock it */ + ld->refcount++; + } + else + ld = NULL; + spin_unlock_irqrestore(&tty_ldisc_lock, flags); + return ld; +} + +EXPORT_SYMBOL_GPL(tty_ldisc_get); + +void tty_ldisc_put(int disc) +{ + struct tty_ldisc *ld; + unsigned long flags; + + if (disc < N_TTY || disc >= NR_LDISCS) + BUG(); + + spin_lock_irqsave(&tty_ldisc_lock, flags); + ld = &tty_ldiscs[disc]; + if(ld->refcount == 0) + BUG(); + ld->refcount --; + module_put(ld->owner); + spin_unlock_irqrestore(&tty_ldisc_lock, flags); +} + +EXPORT_SYMBOL_GPL(tty_ldisc_put); + +static void tty_ldisc_assign(struct tty_struct *tty, struct tty_ldisc *ld) +{ + tty->ldisc = *ld; + tty->ldisc.refcount = 0; +} + +/** + * tty_ldisc_try - internal helper + * @tty: the tty + * + * Make a single attempt to grab and bump the refcount on + * the tty ldisc. Return 0 on failure or 1 on success. This is + * used to implement both the waiting and non waiting versions + * of tty_ldisc_ref + */ + +static int tty_ldisc_try(struct tty_struct *tty) +{ + unsigned long flags; + struct tty_ldisc *ld; + int ret = 0; + + spin_lock_irqsave(&tty_ldisc_lock, flags); + ld = &tty->ldisc; + if(test_bit(TTY_LDISC, &tty->flags)) + { + ld->refcount++; + ret = 1; + } + spin_unlock_irqrestore(&tty_ldisc_lock, flags); + return ret; +} + +/** + * tty_ldisc_ref_wait - wait for the tty ldisc + * @tty: tty device + * + * Dereference the line discipline for the terminal and take a + * reference to it. If the line discipline is in flux then + * wait patiently until it changes. + * + * Note: Must not be called from an IRQ/timer context. The caller + * must also be careful not to hold other locks that will deadlock + * against a discipline change, such as an existing ldisc reference + * (which we check for) + */ + +struct tty_ldisc *tty_ldisc_ref_wait(struct tty_struct *tty) +{ + /* wait_event is a macro */ + wait_event(tty_ldisc_wait, tty_ldisc_try(tty)); + if(tty->ldisc.refcount == 0) + printk(KERN_ERR "tty_ldisc_ref_wait\n"); + return &tty->ldisc; +} + +EXPORT_SYMBOL_GPL(tty_ldisc_ref_wait); + +/** + * tty_ldisc_ref - get the tty ldisc + * @tty: tty device + * + * Dereference the line discipline for the terminal and take a + * reference to it. If the line discipline is in flux then + * return NULL. Can be called from IRQ and timer functions. + */ + +struct tty_ldisc *tty_ldisc_ref(struct tty_struct *tty) +{ + if(tty_ldisc_try(tty)) + return &tty->ldisc; + return NULL; +} + +EXPORT_SYMBOL_GPL(tty_ldisc_ref); + +/** + * tty_ldisc_deref - free a tty ldisc reference + * @ld: reference to free up + * + * Undoes the effect of tty_ldisc_ref or tty_ldisc_ref_wait. May + * be called in IRQ context. + */ + +void tty_ldisc_deref(struct tty_ldisc *ld) +{ + unsigned long flags; + + if(ld == NULL) + BUG(); + + spin_lock_irqsave(&tty_ldisc_lock, flags); + if(ld->refcount == 0) + printk(KERN_ERR "tty_ldisc_deref: no references.\n"); + else + ld->refcount--; + if(ld->refcount == 0) + wake_up(&tty_ldisc_wait); + spin_unlock_irqrestore(&tty_ldisc_lock, flags); +} + +EXPORT_SYMBOL_GPL(tty_ldisc_deref); + +/** + * tty_ldisc_enable - allow ldisc use + * @tty: terminal to activate ldisc on + * + * Set the TTY_LDISC flag when the line discipline can be called + * again. Do neccessary wakeups for existing sleepers. + * + * Note: nobody should set this bit except via this function. Clearing + * directly is allowed. + */ + +static void tty_ldisc_enable(struct tty_struct *tty) +{ + set_bit(TTY_LDISC, &tty->flags); + wake_up(&tty_ldisc_wait); +} + +/** + * tty_set_ldisc - set line discipline + * @tty: the terminal to set + * @ldisc: the line discipline + * + * Set the discipline of a tty line. Must be called from a process + * context. + */ + +static int tty_set_ldisc(struct tty_struct *tty, int ldisc) +{ + int retval = 0; + struct tty_ldisc o_ldisc; + char buf[64]; + int work; + unsigned long flags; + struct tty_ldisc *ld; + + if ((ldisc < N_TTY) || (ldisc >= NR_LDISCS)) + return -EINVAL; + +restart: + + if (tty->ldisc.num == ldisc) + return 0; /* We are already in the desired discipline */ + + ld = tty_ldisc_get(ldisc); + /* Eduardo Blanco <ejbs@cs.cs.com.uy> */ + /* Cyrus Durgin <cider@speakeasy.org> */ + if (ld == NULL) { + request_module("tty-ldisc-%d", ldisc); + ld = tty_ldisc_get(ldisc); + } + if (ld == NULL) + return -EINVAL; + + o_ldisc = tty->ldisc; + + tty_wait_until_sent(tty, 0); + + /* + * Make sure we don't change while someone holds a + * reference to the line discipline. The TTY_LDISC bit + * prevents anyone taking a reference once it is clear. + * We need the lock to avoid racing reference takers. + */ + + spin_lock_irqsave(&tty_ldisc_lock, flags); + if(tty->ldisc.refcount) + { + /* Free the new ldisc we grabbed. Must drop the lock + first. */ + spin_unlock_irqrestore(&tty_ldisc_lock, flags); + tty_ldisc_put(ldisc); + /* + * There are several reasons we may be busy, including + * random momentary I/O traffic. We must therefore + * retry. We could distinguish between blocking ops + * and retries if we made tty_ldisc_wait() smarter. That + * is up for discussion. + */ + if(wait_event_interruptible(tty_ldisc_wait, tty->ldisc.refcount == 0) < 0) + return -ERESTARTSYS; + goto restart; + } + clear_bit(TTY_LDISC, &tty->flags); + clear_bit(TTY_DONT_FLIP, &tty->flags); + spin_unlock_irqrestore(&tty_ldisc_lock, flags); + + /* + * From this point on we know nobody has an ldisc + * usage reference, nor can they obtain one until + * we say so later on. + */ + + work = cancel_delayed_work(&tty->flip.work); + /* + * Wait for ->hangup_work and ->flip.work handlers to terminate + */ + + flush_scheduled_work(); + /* Shutdown the current discipline. */ + if (tty->ldisc.close) + (tty->ldisc.close)(tty); + + /* Now set up the new line discipline. */ + tty_ldisc_assign(tty, ld); + tty_set_termios_ldisc(tty, ldisc); + if (tty->ldisc.open) + retval = (tty->ldisc.open)(tty); + if (retval < 0) { + tty_ldisc_put(ldisc); + /* There is an outstanding reference here so this is safe */ + tty_ldisc_assign(tty, tty_ldisc_get(o_ldisc.num)); + tty_set_termios_ldisc(tty, tty->ldisc.num); + if (tty->ldisc.open && (tty->ldisc.open(tty) < 0)) { + tty_ldisc_put(o_ldisc.num); + /* This driver is always present */ + tty_ldisc_assign(tty, tty_ldisc_get(N_TTY)); + tty_set_termios_ldisc(tty, N_TTY); + if (tty->ldisc.open) { + int r = tty->ldisc.open(tty); + + if (r < 0) + panic("Couldn't open N_TTY ldisc for " + "%s --- error %d.", + tty_name(tty, buf), r); + } + } + } + /* At this point we hold a reference to the new ldisc and a + a reference to the old ldisc. If we ended up flipping back + to the existing ldisc we have two references to it */ + + if (tty->ldisc.num != o_ldisc.num && tty->driver->set_ldisc) + tty->driver->set_ldisc(tty); + + tty_ldisc_put(o_ldisc.num); + + /* + * Allow ldisc referencing to occur as soon as the driver + * ldisc callback completes. + */ + + tty_ldisc_enable(tty); + + /* Restart it in case no characters kick it off. Safe if + already running */ + if(work) + schedule_delayed_work(&tty->flip.work, 1); + return retval; +} + +/* + * This routine returns a tty driver structure, given a device number + */ +static struct tty_driver *get_tty_driver(dev_t device, int *index) +{ + struct tty_driver *p; + + list_for_each_entry(p, &tty_drivers, tty_drivers) { + dev_t base = MKDEV(p->major, p->minor_start); + if (device < base || device >= base + p->num) + continue; + *index = device - base; + return p; + } + return NULL; +} + +/* + * If we try to write to, or set the state of, a terminal and we're + * not in the foreground, send a SIGTTOU. If the signal is blocked or + * ignored, go ahead and perform the operation. (POSIX 7.2) + */ +int tty_check_change(struct tty_struct * tty) +{ + if (current->signal->tty != tty) + return 0; + if (tty->pgrp <= 0) { + printk(KERN_WARNING "tty_check_change: tty->pgrp <= 0!\n"); + return 0; + } + if (process_group(current) == tty->pgrp) + return 0; + if (is_ignored(SIGTTOU)) + return 0; + if (is_orphaned_pgrp(process_group(current))) + return -EIO; + (void) kill_pg(process_group(current), SIGTTOU, 1); + return -ERESTARTSYS; +} + +EXPORT_SYMBOL(tty_check_change); + +static ssize_t hung_up_tty_read(struct file * file, char __user * buf, + size_t count, loff_t *ppos) +{ + return 0; +} + +static ssize_t hung_up_tty_write(struct file * file, const char __user * buf, + size_t count, loff_t *ppos) +{ + return -EIO; +} + +/* No kernel lock held - none needed ;) */ +static unsigned int hung_up_tty_poll(struct file * filp, poll_table * wait) +{ + return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM; +} + +static int hung_up_tty_ioctl(struct inode * inode, struct file * file, + unsigned int cmd, unsigned long arg) +{ + return cmd == TIOCSPGRP ? -ENOTTY : -EIO; +} + +static struct file_operations tty_fops = { + .llseek = no_llseek, + .read = tty_read, + .write = tty_write, + .poll = tty_poll, + .ioctl = tty_ioctl, + .open = tty_open, + .release = tty_release, + .fasync = tty_fasync, +}; + +#ifdef CONFIG_UNIX98_PTYS +static struct file_operations ptmx_fops = { + .llseek = no_llseek, + .read = tty_read, + .write = tty_write, + .poll = tty_poll, + .ioctl = tty_ioctl, + .open = ptmx_open, + .release = tty_release, + .fasync = tty_fasync, +}; +#endif + +static struct file_operations console_fops = { + .llseek = no_llseek, + .read = tty_read, + .write = redirected_tty_write, + .poll = tty_poll, + .ioctl = tty_ioctl, + .open = tty_open, + .release = tty_release, + .fasync = tty_fasync, +}; + +static struct file_operations hung_up_tty_fops = { + .llseek = no_llseek, + .read = hung_up_tty_read, + .write = hung_up_tty_write, + .poll = hung_up_tty_poll, + .ioctl = hung_up_tty_ioctl, + .release = tty_release, +}; + +static DEFINE_SPINLOCK(redirect_lock); +static struct file *redirect; + +/** + * tty_wakeup - request more data + * @tty: terminal + * + * Internal and external helper for wakeups of tty. This function + * informs the line discipline if present that the driver is ready + * to receive more output data. + */ + +void tty_wakeup(struct tty_struct *tty) +{ + struct tty_ldisc *ld; + + if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) { + ld = tty_ldisc_ref(tty); + if(ld) { + if(ld->write_wakeup) + ld->write_wakeup(tty); + tty_ldisc_deref(ld); + } + } + wake_up_interruptible(&tty->write_wait); +} + +EXPORT_SYMBOL_GPL(tty_wakeup); + +/** + * tty_ldisc_flush - flush line discipline queue + * @tty: tty + * + * Flush the line discipline queue (if any) for this tty. If there + * is no line discipline active this is a no-op. + */ + +void tty_ldisc_flush(struct tty_struct *tty) +{ + struct tty_ldisc *ld = tty_ldisc_ref(tty); + if(ld) { + if(ld->flush_buffer) + ld->flush_buffer(tty); + tty_ldisc_deref(ld); + } +} + +EXPORT_SYMBOL_GPL(tty_ldisc_flush); + +/* + * This can be called by the "eventd" kernel thread. That is process synchronous, + * but doesn't hold any locks, so we need to make sure we have the appropriate + * locks for what we're doing.. + */ +static void do_tty_hangup(void *data) +{ + struct tty_struct *tty = (struct tty_struct *) data; + struct file * cons_filp = NULL; + struct file *filp, *f = NULL; + struct task_struct *p; + struct tty_ldisc *ld; + int closecount = 0, n; + + if (!tty) + return; + + /* inuse_filps is protected by the single kernel lock */ + lock_kernel(); + + spin_lock(&redirect_lock); + if (redirect && redirect->private_data == tty) { + f = redirect; + redirect = NULL; + } + spin_unlock(&redirect_lock); + + check_tty_count(tty, "do_tty_hangup"); + file_list_lock(); + /* This breaks for file handles being sent over AF_UNIX sockets ? */ + list_for_each_entry(filp, &tty->tty_files, f_list) { + 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; + } + file_list_unlock(); + + /* FIXME! What are the locking issues here? This may me overdoing things.. + * this question is especially important now that we've removed the irqlock. */ + + ld = tty_ldisc_ref(tty); + if(ld != NULL) /* We may have no line discipline at this point */ + { + if (ld->flush_buffer) + ld->flush_buffer(tty); + if (tty->driver->flush_buffer) + tty->driver->flush_buffer(tty); + if ((test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) && + ld->write_wakeup) + ld->write_wakeup(tty); + if (ld->hangup) + ld->hangup(tty); + } + + /* FIXME: Once we trust the LDISC code better we can wait here for + ldisc completion and fix the driver call race */ + + wake_up_interruptible(&tty->write_wait); + wake_up_interruptible(&tty->read_wait); + + /* + * Shutdown the current line discipline, and reset it to + * N_TTY. + */ + if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) + { + down(&tty->termios_sem); + *tty->termios = tty->driver->init_termios; + up(&tty->termios_sem); + } + + /* Defer ldisc switch */ + /* tty_deferred_ldisc_switch(N_TTY); + + This should get done automatically when the port closes and + tty_release is called */ + + read_lock(&tasklist_lock); + if (tty->session > 0) { + do_each_task_pid(tty->session, PIDTYPE_SID, p) { + if (p->signal->tty == tty) + p->signal->tty = NULL; + if (!p->signal->leader) + continue; + send_group_sig_info(SIGHUP, SEND_SIG_PRIV, p); + send_group_sig_info(SIGCONT, SEND_SIG_PRIV, p); + if (tty->pgrp > 0) + p->signal->tty_old_pgrp = tty->pgrp; + } while_each_task_pid(tty->session, PIDTYPE_SID, p); + } + read_unlock(&tasklist_lock); + + tty->flags = 0; + tty->session = 0; + tty->pgrp = -1; + tty->ctrl_status = 0; + /* + * 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->driver->close) + for (n = 0; n < closecount; n++) + tty->driver->close(tty, cons_filp); + } else if (tty->driver->hangup) + (tty->driver->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. However we + can't yet guarantee all that */ + + set_bit(TTY_HUPPED, &tty->flags); + if (ld) { + tty_ldisc_enable(tty); + tty_ldisc_deref(ld); + } + unlock_kernel(); + if (f) + fput(f); +} + +void tty_hangup(struct tty_struct * tty) +{ +#ifdef TTY_DEBUG_HANGUP + char buf[64]; + + printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf)); +#endif + schedule_work(&tty->hangup_work); +} + +EXPORT_SYMBOL(tty_hangup); + +void tty_vhangup(struct tty_struct * tty) +{ +#ifdef TTY_DEBUG_HANGUP + char buf[64]; + + printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf)); +#endif + do_tty_hangup((void *) tty); +} +EXPORT_SYMBOL(tty_vhangup); + +int tty_hung_up_p(struct file * filp) +{ + return (filp->f_op == &hung_up_tty_fops); +} + +EXPORT_SYMBOL(tty_hung_up_p); + +/* + * This function is typically called only by the session leader, when + * it wants to disassociate itself from its controlling tty. + * + * It performs the following functions: + * (1) Sends a SIGHUP and SIGCONT to the foreground process group + * (2) Clears the tty from being controlling the session + * (3) Clears the controlling tty for all processes in the + * session group. + * + * The argument on_exit is set to 1 if called when a process is + * exiting; it is 0 if called by the ioctl TIOCNOTTY. + */ +void disassociate_ctty(int on_exit) +{ + struct tty_struct *tty; + struct task_struct *p; + int tty_pgrp = -1; + + lock_kernel(); + + down(&tty_sem); + tty = current->signal->tty; + if (tty) { + tty_pgrp = tty->pgrp; + up(&tty_sem); + if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY) + tty_vhangup(tty); + } else { + if (current->signal->tty_old_pgrp) { + kill_pg(current->signal->tty_old_pgrp, SIGHUP, on_exit); + kill_pg(current->signal->tty_old_pgrp, SIGCONT, on_exit); + } + up(&tty_sem); + unlock_kernel(); + return; + } + if (tty_pgrp > 0) { + kill_pg(tty_pgrp, SIGHUP, on_exit); + if (!on_exit) + kill_pg(tty_pgrp, SIGCONT, on_exit); + } + + /* Must lock changes to tty_old_pgrp */ + down(&tty_sem); + current->signal->tty_old_pgrp = 0; + tty->session = 0; + tty->pgrp = -1; + + /* Now clear signal->tty under the lock */ + read_lock(&tasklist_lock); + do_each_task_pid(current->signal->session, PIDTYPE_SID, p) { + p->signal->tty = NULL; + } while_each_task_pid(current->signal->session, PIDTYPE_SID, p); + read_unlock(&tasklist_lock); + up(&tty_sem); + unlock_kernel(); +} + +void stop_tty(struct tty_struct *tty) +{ + if (tty->stopped) + return; + tty->stopped = 1; + if (tty->link && tty->link->packet) { + tty->ctrl_status &= ~TIOCPKT_START; + tty->ctrl_status |= TIOCPKT_STOP; + wake_up_interruptible(&tty->link->read_wait); + } + if (tty->driver->stop) + (tty->driver->stop)(tty); +} + +EXPORT_SYMBOL(stop_tty); + +void start_tty(struct tty_struct *tty) +{ + if (!tty->stopped || tty->flow_stopped) + return; + tty->stopped = 0; + if (tty->link && tty->link->packet) { + tty->ctrl_status &= ~TIOCPKT_STOP; + tty->ctrl_status |= TIOCPKT_START; + wake_up_interruptible(&tty->link->read_wait); + } + if (tty->driver->start) + (tty->driver->start)(tty); + + /* If we have a running line discipline it may need kicking */ + tty_wakeup(tty); + wake_up_interruptible(&tty->write_wait); +} + +EXPORT_SYMBOL(start_tty); + +static ssize_t tty_read(struct file * file, char __user * buf, size_t count, + loff_t *ppos) +{ + int i; + struct tty_struct * tty; + struct inode *inode; + struct tty_ldisc *ld; + + tty = (struct tty_struct *)file->private_data; + inode = file->f_dentry->d_inode; + if (tty_paranoia_check(tty, inode, "tty_read")) + return -EIO; + if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags))) + return -EIO; + + /* We want to wait for the line discipline to sort out in this + situation */ + ld = tty_ldisc_ref_wait(tty); + lock_kernel(); + if (ld->read) + i = (ld->read)(tty,file,buf,count); + else + i = -EIO; + tty_ldisc_deref(ld); + unlock_kernel(); + if (i > 0) + inode->i_atime = current_fs_time(inode->i_sb); + return i; +} + +/* + * 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 = 0, written = 0; + unsigned int chunk; + + if (down_interruptible(&tty->atomic_write)) { + return -ERESTARTSYS; + } + + /* + * 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. + */ + 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 semaphore */ + if (tty->write_cnt < chunk) { + unsigned char *buf; + + if (chunk < 1024) + chunk = 1024; + + buf = kmalloc(chunk, GFP_KERNEL); + if (!buf) { + up(&tty->atomic_write); + return -ENOMEM; + } + kfree(tty->write_buf); + tty->write_cnt = chunk; + tty->write_buf = buf; + } + + /* 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; + lock_kernel(); + ret = write(tty, file, tty->write_buf, size); + unlock_kernel(); + if (ret <= 0) + break; + written += ret; + buf += ret; + count -= ret; + if (!count) + break; + ret = -ERESTARTSYS; + if (signal_pending(current)) + break; + cond_resched(); + } + if (written) { + struct inode *inode = file->f_dentry->d_inode; + inode->i_mtime = current_fs_time(inode->i_sb); + ret = written; + } + up(&tty->atomic_write); + return ret; +} + + +static ssize_t tty_write(struct file * file, const char __user * buf, size_t count, + loff_t *ppos) +{ + struct tty_struct * tty; + struct inode *inode = file->f_dentry->d_inode; + ssize_t ret; + struct tty_ldisc *ld; + + tty = (struct tty_struct *)file->private_data; + if (tty_paranoia_check(tty, inode, "tty_write")) + return -EIO; + if (!tty || !tty->driver->write || (test_bit(TTY_IO_ERROR, &tty->flags))) + return -EIO; + + ld = tty_ldisc_ref_wait(tty); + if (!ld->write) + ret = -EIO; + else + ret = do_tty_write(ld->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) { + get_file(redirect); + p = 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); +} + +static char ptychar[] = "pqrstuvwxyzabcde"; + +static inline 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); +} + +static inline void tty_line_name(struct tty_driver *driver, int index, char *p) +{ + sprintf(p, "%s%d", driver->name, index + driver->name_base); +} + +/* + * WSH 06/09/97: Rewritten to remove races and properly clean up after a + * failed open. The new code protects the open with a semaphore, so it's + * really quite straightforward. The semaphore locking can probably be + * relaxed for the (most common) case of reopening a tty. + */ +static int init_dev(struct tty_driver *driver, int idx, + struct tty_struct **ret_tty) +{ + struct tty_struct *tty, *o_tty; + struct termios *tp, **tp_loc, *o_tp, **o_tp_loc; + struct termios *ltp, **ltp_loc, *o_ltp, **o_ltp_loc; + int retval=0; + + /* check whether we're reopening an existing tty */ + if (driver->flags & TTY_DRIVER_DEVPTS_MEM) { + tty = devpts_get_tty(idx); + if (tty && driver->subtype == PTY_TYPE_MASTER) + tty = tty->link; + } else { + tty = driver->ttys[idx]; + } + if (tty) goto fast_track; + + /* + * 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 + * and locked termios may be retained.) + */ + + if (!try_module_get(driver->owner)) { + retval = -ENODEV; + goto end_init; + } |