/drivers/tty/tty_io.c
C | 1923 lines | 1126 code | 211 blank | 586 comment | 207 complexity | eda5b076f2e068263b40367008e28ede MD5 | raw file
- /*
- * 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 tty_init_dev and tty_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/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/fdtable.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/device.h>
- #include <linux/wait.h>
- #include <linux/bitops.h>
- #include <linux/delay.h>
- #include <linux/seq_file.h>
- #include <linux/serial.h>
- #include <linux/ratelimit.h>
- #include <linux/uaccess.h>
- #include <asm/system.h>
- #include <linux/kbd_kern.h>
- #include <linux/vt_kern.h>
- #include <linux/selection.h>
- #include <linux/kmod.h>
- #include <linux/nsproxy.h>
- #undef TTY_DEBUG_HANGUP
- #define TTY_PARANOIA_CHECK 1
- #define CHECK_TTY_COUNT 1
- struct ktermios 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,
- .c_ispeed = 38400,
- .c_ospeed = 38400
- };
- 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 */
- /* Mutex to protect creating and releasing a tty. This is shared with
- vt.c for deeply disgusting hack reasons */
- DEFINE_MUTEX(tty_mutex);
- EXPORT_SYMBOL(tty_mutex);
- /* Spinlock to protect the tty->tty_files list */
- DEFINE_SPINLOCK(tty_files_lock);
- 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 *);
- long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
- #ifdef CONFIG_COMPAT
- static long tty_compat_ioctl(struct file *file, unsigned int cmd,
- unsigned long arg);
- #else
- #define tty_compat_ioctl NULL
- #endif
- static int __tty_fasync(int fd, struct file *filp, int on);
- static int tty_fasync(int fd, struct file *filp, int on);
- static void release_tty(struct tty_struct *tty, int idx);
- static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
- static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
- /**
- * alloc_tty_struct - allocate a tty object
- *
- * Return a new empty tty structure. The data fields have not
- * been initialized in any way but has been zeroed
- *
- * Locking: none
- */
- struct tty_struct *alloc_tty_struct(void)
- {
- return kzalloc(sizeof(struct tty_struct), GFP_KERNEL);
- }
- /**
- * free_tty_struct - free a disused tty
- * @tty: tty struct to free
- *
- * Free the write buffers, tty queue and tty memory itself.
- *
- * Locking: none. Must be called after tty is definitely unused
- */
- void free_tty_struct(struct tty_struct *tty)
- {
- if (tty->dev)
- put_device(tty->dev);
- kfree(tty->write_buf);
- tty_buffer_free_all(tty);
- kfree(tty);
- }
- static inline struct tty_struct *file_tty(struct file *file)
- {
- return ((struct tty_file_private *)file->private_data)->tty;
- }
- /* Associate a new file with the tty structure */
- int tty_add_file(struct tty_struct *tty, struct file *file)
- {
- struct tty_file_private *priv;
- priv = kmalloc(sizeof(*priv), GFP_KERNEL);
- if (!priv)
- return -ENOMEM;
- priv->tty = tty;
- priv->file = file;
- file->private_data = priv;
- spin_lock(&tty_files_lock);
- list_add(&priv->list, &tty->tty_files);
- spin_unlock(&tty_files_lock);
- return 0;
- }
- /* Delete file from its tty */
- void tty_del_file(struct file *file)
- {
- struct tty_file_private *priv = file->private_data;
- spin_lock(&tty_files_lock);
- list_del(&priv->list);
- spin_unlock(&tty_files_lock);
- file->private_data = NULL;
- kfree(priv);
- }
- #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
- /**
- * tty_name - return tty naming
- * @tty: tty structure
- * @buf: buffer for output
- *
- * Convert a tty structure into a name. The name reflects the kernel
- * naming policy and if udev is in use may not reflect user space
- *
- * Locking: none
- */
- 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);
- 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;
- spin_lock(&tty_files_lock);
- list_for_each(p, &tty->tty_files) {
- count++;
- }
- spin_unlock(&tty_files_lock);
- 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;
- }
- /**
- * get_tty_driver - find device of a tty
- * @dev_t: device identifier
- * @index: returns the index of the tty
- *
- * This routine returns a tty driver structure, given a device number
- * and also passes back the index number.
- *
- * Locking: caller must hold tty_mutex
- */
- 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 tty_driver_kref_get(p);
- }
- return NULL;
- }
- #ifdef CONFIG_CONSOLE_POLL
- /**
- * tty_find_polling_driver - find device of a polled tty
- * @name: name string to match
- * @line: pointer to resulting tty line nr
- *
- * This routine returns a tty driver structure, given a name
- * and the condition that the tty driver is capable of polled
- * operation.
- */
- struct tty_driver *tty_find_polling_driver(char *name, int *line)
- {
- struct tty_driver *p, *res = NULL;
- int tty_line = 0;
- int len;
- char *str, *stp;
- for (str = name; *str; str++)
- if ((*str >= '0' && *str <= '9') || *str == ',')
- break;
- if (!*str)
- return NULL;
- len = str - name;
- tty_line = simple_strtoul(str, &str, 10);
- mutex_lock(&tty_mutex);
- /* Search through the tty devices to look for a match */
- list_for_each_entry(p, &tty_drivers, tty_drivers) {
- if (strncmp(name, p->name, len) != 0)
- continue;
- stp = str;
- if (*stp == ',')
- stp++;
- if (*stp == '\0')
- stp = NULL;
- if (tty_line >= 0 && tty_line < p->num && p->ops &&
- p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
- res = tty_driver_kref_get(p);
- *line = tty_line;
- break;
- }
- }
- mutex_unlock(&tty_mutex);
- return res;
- }
- EXPORT_SYMBOL_GPL(tty_find_polling_driver);
- #endif
- /**
- * tty_check_change - check for POSIX terminal changes
- * @tty: tty to check
- *
- * 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)
- *
- * Locking: ctrl_lock
- */
- int tty_check_change(struct tty_struct *tty)
- {
- unsigned long flags;
- int ret = 0;
- if (current->signal->tty != tty)
- return 0;
- spin_lock_irqsave(&tty->ctrl_lock, flags);
- if (!tty->pgrp) {
- printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n");
- goto out_unlock;
- }
- if (task_pgrp(current) == tty->pgrp)
- goto out_unlock;
- spin_unlock_irqrestore(&tty->ctrl_lock, flags);
- if (is_ignored(SIGTTOU))
- goto out;
- if (is_current_pgrp_orphaned()) {
- ret = -EIO;
- goto out;
- }
- kill_pgrp(task_pgrp(current), SIGTTOU, 1);
- set_thread_flag(TIF_SIGPENDING);
- ret = -ERESTARTSYS;
- out:
- return ret;
- out_unlock:
- spin_unlock_irqrestore(&tty->ctrl_lock, flags);
- return ret;
- }
- 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 long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
- unsigned long arg)
- {
- return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
- }
- static long hung_up_tty_compat_ioctl(struct file *file,
- unsigned int cmd, unsigned long arg)
- {
- return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
- }
- static const struct file_operations tty_fops = {
- .llseek = no_llseek,
- .read = tty_read,
- .write = tty_write,
- .poll = tty_poll,
- .unlocked_ioctl = tty_ioctl,
- .compat_ioctl = tty_compat_ioctl,
- .open = tty_open,
- .release = tty_release,
- .fasync = tty_fasync,
- };
- static const struct file_operations console_fops = {
- .llseek = no_llseek,
- .read = tty_read,
- .write = redirected_tty_write,
- .poll = tty_poll,
- .unlocked_ioctl = tty_ioctl,
- .compat_ioctl = tty_compat_ioctl,
- .open = tty_open,
- .release = tty_release,
- .fasync = tty_fasync,
- };
- static const 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,
- .unlocked_ioctl = hung_up_tty_ioctl,
- .compat_ioctl = hung_up_tty_compat_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->ops->write_wakeup)
- ld->ops->write_wakeup(tty);
- tty_ldisc_deref(ld);
- }
- }
- wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
- }
- EXPORT_SYMBOL_GPL(tty_wakeup);
- /**
- * __tty_hangup - actual handler for hangup events
- * @work: tty device
- *
- * 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.
- *
- * The hangup event clears any pending redirections onto the hung up
- * device. It ensures future writes will error and it does the needed
- * line discipline hangup and signal delivery. The tty object itself
- * remains intact.
- *
- * Locking:
- * BTM
- * redirect lock for undoing redirection
- * file list lock for manipulating list of ttys
- * tty_ldisc_lock from called functions
- * termios_mutex resetting termios data
- * tasklist_lock to walk task list for hangup event
- * ->siglock to protect ->signal/->sighand
- */
- void __tty_hangup(struct tty_struct *tty)
- {
- struct file *cons_filp = NULL;
- struct file *filp, *f = NULL;
- struct task_struct *p;
- struct tty_file_private *priv;
- int closecount = 0, n;
- unsigned long flags;
- int refs = 0;
- if (!tty)
- return;
- spin_lock(&redirect_lock);
- if (redirect && file_tty(redirect) == tty) {
- f = redirect;
- redirect = NULL;
- }
- spin_unlock(&redirect_lock);
- tty_lock();
- /* some functions below drop BTM, so we need this bit */
- set_bit(TTY_HUPPING, &tty->flags);
- /* 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);
- /*
- * it drops BTM and thus races with reopen
- * we protect the race by TTY_HUPPING
- */
- tty_ldisc_hangup(tty);
- read_lock(&tasklist_lock);
- if (tty->session) {
- do_each_pid_task(tty->session, PIDTYPE_SID, p) {
- spin_lock_irq(&p->sighand->siglock);
- if (p->signal->tty == tty) {
- p->signal->tty = NULL;
- /* We defer the dereferences outside fo
- the tasklist lock */
- refs++;
- }
- if (!p->signal->leader) {
- spin_unlock_irq(&p->sighand->siglock);
- continue;
- }
- __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
- __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
- put_pid(p->signal->tty_old_pgrp); /* A noop */
- spin_lock_irqsave(&tty->ctrl_lock, flags);
- if (tty->pgrp)
- p->signal->tty_old_pgrp = get_pid(tty->pgrp);
- spin_unlock_irqrestore(&tty->ctrl_lock, flags);
- spin_unlock_irq(&p->sighand->siglock);
- } while_each_pid_task(tty->session, PIDTYPE_SID, p);
- }
- read_unlock(&tasklist_lock);
- spin_lock_irqsave(&tty->ctrl_lock, flags);
- clear_bit(TTY_THROTTLED, &tty->flags);
- clear_bit(TTY_PUSH, &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_irqrestore(&tty->ctrl_lock, flags);
- /* Account for the p->signal references we killed */
- while (refs--)
- tty_kref_put(tty);
- /*
- * 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. However we
- * can't yet guarantee all that.
- */
- set_bit(TTY_HUPPED, &tty->flags);
- clear_bit(TTY_HUPPING, &tty->flags);
- tty_ldisc_enable(tty);
- tty_unlock();
- 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);
- }
- /**
- * 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)
- {
- #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);
- /**
- * 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)
- {
- #ifdef TTY_DEBUG_HANGUP
- char buf[64];
- printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf));
- #endif
- __tty_hangup(tty);
- }
- 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_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->f_op == &hung_up_tty_fops);
- }
- EXPORT_SYMBOL(tty_hung_up_p);
- static void session_clear_tty(struct pid *session)
- {
- struct task_struct *p;
- do_each_pid_task(session, PIDTYPE_SID, p) {
- proc_clear_tty(p);
- } while_each_pid_task(session, PIDTYPE_SID, p);
- }
- /**
- * disassociate_ctty - disconnect controlling tty
- * @on_exit: true if exiting so need to "hang up" the session
- *
- * 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.
- *
- * Locking:
- * BTM is taken for hysterical raisins, and held when
- * called from no_tty().
- * tty_mutex is taken to protect tty
- * ->siglock is taken to protect ->signal/->sighand
- * tasklist_lock is taken to walk process list for sessions
- * ->siglock is taken to protect ->signal/->sighand
- */
- void disassociate_ctty(int on_exit)
- {
- struct tty_struct *tty;
- struct pid *tty_pgrp = NULL;
- if (!current->signal->leader)
- return;
- tty = get_current_tty();
- if (tty) {
- tty_pgrp = get_pid(tty->pgrp);
- if (on_exit) {
- if (tty->driver->type != TTY_DRIVER_TYPE_PTY)
- tty_vhangup(tty);
- }
- tty_kref_put(tty);
- } else if (on_exit) {
- struct pid *old_pgrp;
- spin_lock_irq(¤t->sighand->siglock);
- old_pgrp = current->signal->tty_old_pgrp;
- current->signal->tty_old_pgrp = NULL;
- spin_unlock_irq(¤t->sighand->siglock);
- if (old_pgrp) {
- kill_pgrp(old_pgrp, SIGHUP, on_exit);
- kill_pgrp(old_pgrp, SIGCONT, on_exit);
- put_pid(old_pgrp);
- }
- return;
- }
- if (tty_pgrp) {
- kill_pgrp(tty_pgrp, SIGHUP, on_exit);
- if (!on_exit)
- kill_pgrp(tty_pgrp, SIGCONT, on_exit);
- put_pid(tty_pgrp);
- }
- spin_lock_irq(¤t->sighand->siglock);
- put_pid(current->signal->tty_old_pgrp);
- current->signal->tty_old_pgrp = NULL;
- spin_unlock_irq(¤t->sighand->siglock);
- tty = get_current_tty();
- if (tty) {
- unsigned long flags;
- spin_lock_irqsave(&tty->ctrl_lock, flags);
- put_pid(tty->session);
- put_pid(tty->pgrp);
- tty->session = NULL;
- tty->pgrp = NULL;
- spin_unlock_irqrestore(&tty->ctrl_lock, flags);
- tty_kref_put(tty);
- } else {
- #ifdef TTY_DEBUG_HANGUP
- printk(KERN_DEBUG "error attempted to write to tty [0x%p]"
- " = NULL", tty);
- #endif
- }
- /* Now clear signal->tty under the lock */
- read_lock(&tasklist_lock);
- session_clear_tty(task_session(current));
- read_unlock(&tasklist_lock);
- }
- /**
- *
- * no_tty - Ensure the current process does not have a controlling tty
- */
- void no_tty(void)
- {
- struct task_struct *tsk = current;
- tty_lock();
- disassociate_ctty(0);
- tty_unlock();
- proc_clear_tty(tsk);
- }
- /**
- * stop_tty - propagate flow control
- * @tty: tty to stop
- *
- * Perform flow control to the driver. For PTY/TTY pairs we
- * must also propagate the TIOCKPKT status. 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:
- * Uses the tty control lock internally
- */
- void stop_tty(struct tty_struct *tty)
- {
- unsigned long flags;
- spin_lock_irqsave(&tty->ctrl_lock, flags);
- if (tty->stopped) {
- spin_unlock_irqrestore(&tty->ctrl_lock, flags);
- return;
- }
- tty->stopped = 1;
- if (tty->link && tty->link->packet) {
- tty->ctrl_status &= ~TIOCPKT_START;
- tty->ctrl_status |= TIOCPKT_STOP;
- wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
- }
- spin_unlock_irqrestore(&tty->ctrl_lock, flags);
- if (tty->ops->stop)
- (tty->ops->stop)(tty);
- }
- EXPORT_SYMBOL(stop_tty);
- /**
- * start_tty - propagate flow control
- * @tty: tty to start
- *
- * Start a tty that has been stopped if at all possible. Perform
- * any necessary wakeups and propagate the TIOCPKT status. If this
- * is the tty was previous stopped and is being started then the
- * driver start method is invoked and the line discipline woken.
- *
- * Locking:
- * ctrl_lock
- */
- void start_tty(struct tty_struct *tty)
- {
- unsigned long flags;
- spin_lock_irqsave(&tty->ctrl_lock, flags);
- if (!tty->stopped || tty->flow_stopped) {
- spin_unlock_irqrestore(&tty->ctrl_lock, flags);
- return;
- }
- tty->stopped = 0;
- if (tty->link && tty->link->packet) {
- tty->ctrl_status &= ~TIOCPKT_STOP;
- tty->ctrl_status |= TIOCPKT_START;
- wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
- }
- spin_unlock_irqrestore(&tty->ctrl_lock, flags);
- if (tty->ops->start)
- (tty->ops->start)(tty);
- /* If we have a running line discipline it may need kicking */
- tty_wakeup(tty);
- }
- EXPORT_SYMBOL(start_tty);
- /**
- * 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->f_path.dentry->d_inode;
- struct tty_struct *tty = file_tty(file);
- struct tty_ldisc *ld;
- 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);
- if (ld->ops->read)
- i = (ld->ops->read)(tty, file, buf, count);
- else
- i = -EIO;
- tty_ldisc_deref(ld);
- if (i > 0)
- inode->i_atime = current_fs_time(inode->i_sb);
- return i;
- }
- void tty_write_unlock(struct tty_struct *tty)
- __releases(&tty->atomic_write_lock)
- {
- mutex_unlock(&tty->atomic_write_lock);
- wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
- }
- int tty_write_lock(struct tty_struct *tty, int ndelay)
- __acquires(&tty->atomic_write_lock)
- {
- 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) {
- struct inode *inode = file->f_path.dentry->d_inode;
- inode->i_mtime = current_fs_time(inode->i_sb);
- 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();
- if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags)) {
- tty_unlock();
- tty->ops->write(tty, msg, strlen(msg));
- } else
- tty_unlock();
- 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 inode *inode = file->f_path.dentry->d_inode;
- struct tty_struct *tty = file_tty(file);
- struct tty_ldisc *ld;
- ssize_t ret;
- if (tty_paranoia_check(tty, inode, "tty_write"))
- return -EIO;
- if (!tty || !tty->ops->write ||
- (test_bit(TTY_IO_ERROR, &tty->flags)))
- return -EIO;
- /* Short term debug to catch buggy drivers */
- if (tty->ops->write_room == NULL)
- printk(KERN_ERR "tty driver %s lacks a write_room method.\n",
- tty->driver->name);
- ld = tty_ldisc_ref_wait(tty);
- 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) {
- 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";
- /**
- * 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 void tty_line_name(struct tty_driver *driver, int index, char *p)
- {
- 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 or ERR_PTR() otherwise.
- *
- * Locking: tty_mutex must be held. If tty is found, the mutex must
- * be held until the 'fast-open' is also done. Will change once we
- * have refcounting in the driver and per driver locking
- */
- static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
- struct inode *inode, int idx)
- {
- struct tty_struct *tty;
- if (driver->ops->lookup)
- return driver->ops->lookup(driver, inode, idx);
- tty = driver->ttys[idx];
- 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.
- */
- int tty_init_termios(struct tty_struct *tty)
- {
- struct ktermios *tp;
- int idx = tty->index;
- tp = tty->driver->termios[idx];
- if (tp == NULL) {
- tp = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
- if (tp == NULL)
- return -ENOMEM;
- memcpy(tp, &tty->driver->init_termios,
- sizeof(struct ktermios));
- tty->driver->termios[idx] = tp;
- }
- tty->termios = tp;
- tty->termios_locked = tp + 1;
- /* 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);
- return 0;
- }
- EXPORT_SYMBOL_GPL(tty_init_termios);
- /**
- * 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)
- {
- int idx = tty->index;
- int ret;
- if (driver->ops->install) {
- ret = driver->ops->install(driver, tty);
- return ret;
- }
- if (tty_init_termios(tty) == 0) {
- tty_driver_kref_get(driver);
- tty->count++;
- driver->ttys[idx] = tty;
- return 0;
- }
- return -ENOMEM;
- }
- /**
- * 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
- */
- 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.
- *
- * Locking: tty_mutex must be held from the time the tty was found
- * till this open completes.
- */
- static int tty_reopen(struct tty_struct *tty)
- {
- struct tty_driver *driver = tty->driver;
- if (test_bit(TTY_CLOSING, &tty->flags) ||
- test_bit(TTY_HUPPING, &tty->flags) ||
- test_bit(TTY_LDISC_CHANGING, &tty->flags))
- return -EIO;
- if (driver->type == TTY_DRIVER_TYPE_PTY &&
- driver->subtype == PTY_TYPE_MASTER) {
- /*
- * special case for PTY masters: only one open permitted,
- * and the slave side open count is incremented as well.
- */
- if (tty->count)
- return -EIO;
- tty->link->count++;
- }
- tty->count++;
- tty->driver = driver; /* N.B. why do this every time?? */
- mutex_lock(&tty->ldisc_mutex);
- WARN_ON(!test_bit(TTY_LDISC, &tty->flags));
- mutex_unlock(&tty->ldisc_mutex);
- 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
- * @first_ok: ok to open a new device (used by ptmx)
- *
- * 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,
- int first_ok)
- {
- struct tty_struct *tty;
- int retval;
- /* Check if pty master is being opened multiple times */
- if (driver->subtype == PTY_TYPE_MASTER &&
- (driver->flags & TTY_DRIVER_DEVPTS_MEM) && !first_ok) {
- return ERR_PTR(-EIO);
- }
- /*
- * 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))
- return ERR_PTR(-ENODEV);
- tty = alloc_tty_struct();
- if (!tty) {
- retval = -ENOMEM;
- goto err_module_put;
- }
- initialize_tty_struct(tty, driver, idx);
- retval = tty_driver_install_tty(driver, tty);
- if (retval < 0)
- goto err_deinit_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 tty;
- err_deinit_tty:
- deinitialize_tty_struct(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:
- printk_ratelimited(KERN_INFO "tty_init_dev: ldisc open failed, "
- "clearing slot %d\n", idx);
- release_tty(tty, idx);
- return ERR_PTR(retval);
- }
- void tty_free_termios(struct tty_struct *tty)
- {
- struct ktermios *tp;
- int idx = tty->index;
- /* Kill this flag and push into drivers for locking etc */
- if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) {
- /* FIXME: Locking on ->termios array */
- tp = tty->termios;
- tty->driver->termios[idx] = NULL;
- kfree(tp);
- }
- }
- EXPORT_SYMBOL(tty_free_termios);
- void tty_shutdown(struct tty_struct *tty)
- {
- tty_driver_remove_tty(tty->driver, tty);
- tty_free_termios(tty);
- }
- EXPORT_SYMBOL(tty_shutdown);
- /**
- * 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:
- * tty_mutex - sometimes only
- * 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;
- if (tty->ops->cleanup)
- tty->ops->cleanup(tty);
- tty->magic = 0;
- tty_driver_kref_put(driver);
- module_put(driver->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);
- if (tty->ops->shutdown)
- tty->ops->shutdown(tty);
- else
- tty_shutdown(tty);
- /* 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 - sometimes only
- * takes the file list lock internally when working on the list
- * of ttys that the driver keeps.
- * FIXME: should we require tty_mutex is held here ??
- *
- */
- 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);
- if (tty->link)
- tty_kref_put(tty->link);
- tty_kref_put(tty);
- }
- /**
- * 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;
- int pty_master, tty_closing, o_tty_closing, do_sleep;
- int devpts;
- int idx;
- char buf[64];
- if (tty_paranoia_check(tty, inode, "tty_release_dev"))
- return 0;
- tty_lock();
- check_tty_count(tty, "tty_release_dev");
- __tty_fasync(-1, filp, 0);
- idx = tty->index;
- pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
- tty->driver->subtype == PTY_TYPE_MASTER);
- devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0;
- o_tty = tty->link;
- #ifdef TTY_PARANOIA_CHECK
- if (idx < 0 || idx >= tty->driver->num) {
- printk(KERN_DEBUG "tty_release_dev: bad idx when trying to "
- "free (%s)\n", tty->name);
- tty_unlock();
- return 0;
- }
- if (!devpts) {
- if (tty != tty->driver->ttys[idx]) {
- tty_unlock();
- printk(KERN_DEBUG "tty_release_dev: driver.table[%d] not tty "
- "for (%s)\n", idx, tty->name);
- return 0;
- }
- if (tty->termios != tty->driver->termios[idx]) {
- tty_unlock();
- printk(KERN_DEBUG "tty_release_dev: driver.termios[%d] not termios "
- "for (%s)\n",
- idx, tty->name);
- return 0;
- }
- }
- #endif
- #ifdef TTY_DEBUG_HANGUP
- printk(KERN_DEBUG "tty_release_dev of %s (tty count=%d)...",
- tty_name(tty, buf), tty->count);
- #endif
- #ifdef TTY_PARANOIA_CHECK
- if (tty->driver->other &&
- !(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) {
- if (o_tty != tty->driver->other->ttys[idx]) {
- tty_unlock();
- printk(KERN_DEBUG "tty_release_dev: other->table[%d] "
- "not o_tty for (%s)\n",
- idx, tty->name);
- return 0 ;
- }
- if (o_tty->termios != tty->driver->other->termios[idx]) {
- tty_unlock();
- printk(KERN_DEBUG "tty_release_dev: other->termios[%d] "
- "not o_termios for (%s)\n",
- idx, tty->name);
- return 0;
- }
- if (o_tty->link != tty) {
- tty_unlock();
- printk(KERN_DEBUG "tty_release_dev: bad pty pointers\n");
- return 0;
- }
- }
- #endif
- if (tty->ops->close)
- tty->ops->close(tty, filp);
- tty_unlock();
- /*
- * 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 closes,
- * so we do it now.
- *
- * Note that it's possible for the tty to be opened again while we're
- * flushing out waiters. By recalculating the closing flags before
- * each iteration we avoid any problems.
- */
- while (1) {
- /* Guard against races with tty->count changes elsewhere and
- opens on /dev/tty */
- mutex_lock(&tty_mutex);
- tty_lock();
- tty_closing = tty->count <= 1;
- o_tty_closing = o_tty &&
- (o_tty->count <= (pty_master ? 1 : 0));
- do_sleep = 0;
- if (tty_closing) {
- 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_closing) {
- 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;
- printk(KERN_WARNING "tty_release_dev: %s: read/write wait queue "
- "active!\n", tty_name(tty, buf));
- tty_unlock();
- mutex_unlock(&tty_mutex);
- schedule();
- }
- /*
- * The closing flags are now consistent with the open counts on
- * both sides, and we've completed the last operation that could
- * block, so it's safe to proceed with closing.
- */
- if (pty_master) {
- if (--o_tty->count < 0) {
- printk(KERN_WARNING "tty_release_dev: bad pty slave count "
- "(%d) for %s\n",
- o_tty->count, tty_name(o_tty, buf));
- o_tty->count = 0;
- }
- }
- if (--tty->count < 0) {
- printk(KERN_WARNING "tty_release_dev: bad tty->count (%d) for %s\n",
- tty->count, tty_name(tty, buf));
- 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.
- *
- * Set the TTY_CLOSING flag if this was the last open. In the
- * case of a pty we may have to wait around for the other side
- * to close, and TTY_CLOSING makes sure we can't be reopened.
- */
- if (tty_closing)
- set_bit(TTY_CLOSING, &tty->flags);
- if (o_tty_closing)
- set_bit(TTY_CLOSING, &o_tty->flags);
- /*
- * 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_closing || o_tty_closing) {
- read_lock(&tasklist_lock);
- session_clear_tty(tty->session);
- if (o_tty)
- session_clear_tty(o_tty->session);
- read_unlock(&tasklist_lock);
- }
- mutex_unlock(&tty_mutex);
- /* check whether both sides are closing ... */
- if (!tty_closing || (o_tty && !o_tty_closing)) {
- tty_unlock();
- return 0;
- }
- #ifdef TTY_DEBUG_HANGUP
- printk(KERN_DEBUG "freeing tty structure...");
- #endif
- /*
- * Ask the line discipline code to release its structures
- */
- tty_ldisc_release(tty, o_tty);
- /*
- * The release_tty function takes care of the details of clearing
- * the slots and preserving the termios structure.
- */
- release_tty(tty, idx);
- /* Make this pty number available for reallocation */
- if (devpts)
- devpts_kill_index(inode, idx);
- tty_unlock();
- return 0;
- }
- /**
- * 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, get_tty_driver and tty_init_dev work.
- * tty->count should protect the rest.
- * ->siglock protects ->signal/->sighand
- */
- static int tty_open(struct inode *inode, struct file *filp)
- {
- struct tty_struct *tty = NULL;
- int noctty, retval;
- struct tty_driver *driver;
- int index;
- dev_t device = inode->i_rdev;
- unsigned saved_flags = filp->f_flags;
- nonseekable_open(inode, filp);
- retry_open:
- noctty = filp->f_flags & O_NOCTTY;
- index = -1;
- retval = 0;
- mutex_lock(&tty_mutex);
- tty_lock();
- if (device == MKDEV(TTYAUX_MAJOR, 0)) {
- tty = get_current_tty();
- if (!tty) {
- tty_unlock();
- mutex_unlock(&tty_mutex);
- return -ENXIO;
- }
- driver = tty_driver_kref_get(tty->driver);
- index = tty->index;
- filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
- /* noctty = 1; */
- /* FIXME: Should we take a driver reference ? */
- tty_kref_put(tty);
- goto got_driver;
- }
- #ifdef CONFIG_VT
- if (device == MKDEV(TTY_MAJOR, 0)) {
- extern struct tty_driver *console_driver;
- driver = tty_driver_kref_get(console_driver);
- index = fg_console;
- noctty = 1;
- goto got_driver;
- }
- #endif
- if (device == 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;
- noctty = 1;
- goto got_driver;
- }
- }
- tty_unlock();
- mutex_unlock(&tty_mutex);
- return -ENODEV;
- }
- driver = get_tty_driver(device, &index);
- if (!driver) {
- tty_unlock();
- mutex_unlock(&tty_mutex);
- return -ENODEV;
- }
- got_driver:
- if (!tty) {
- /* check whether we're reopening an existing tty */
- tty = tty_driver_lookup_tty(driver, inode, index);
- if (IS_ERR(tty)) {
- tty_unlock();
- mutex_unlock(&tty_mutex);
- return PTR_ERR(tty);
- }
- }
- if (tty) {
- retval = tty_reopen(tty);
- if (retval)
- tty = ERR_PTR(retval);
- } else
- tty = tty_init_dev(driver, index, 0);
- mutex_unlock(&tty_mutex);
- tty_driver_kref_put(driver);
- if (IS_ERR(tty)) {
- tty_unlock();
- return PTR_ERR(tty);
- }
- retval = tty_add_file(tty, filp);
- if (retval) {
- tty_unlock();
- tty_release(inode, filp);
- return retval;
- }
- check_tty_count(tty, "tty_open");
- if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
- tty->driver->subtype == PTY_TYPE_MASTER)
- noctty = 1;
- #ifdef TTY_DEBUG_HANGUP
- printk(KERN_DEBUG "opening %s...", tty->name);
- #endif
- if (tty->ops->open)
- retval = tty->ops->open(tty, filp);
- else
- retval = -ENODEV;
- filp->f_flags = saved_flags;
- if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) &&
- !capable(CAP_SYS_ADMIN))
- retval = -EBUSY;
- if (retval) {
- #ifdef TTY_DEBUG_HANGUP
- printk(KERN_DEBUG "error %d in opening %s...", retval,
- tty->name);
- #endif
- tty_unlock(); /* need to call tty_release without BTM */
- tty_re