diff options
Diffstat (limited to 'drivers/char/tty_io.c')
| -rw-r--r-- | drivers/char/tty_io.c | 3157 |
1 files changed, 3157 insertions, 0 deletions
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c new file mode 100644 index 0000000..1412a8d --- /dev/null +++ b/drivers/char/tty_io.c @@ -0,0 +1,3157 @@ +/* + * 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 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/smp_lock.h> +#include <linux/device.h> +#include <linux/wait.h> +#include <linux/bitops.h> +#include <linux/delay.h> +#include <linux/seq_file.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); + +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 *); +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 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) +{ + kfree(tty->write_buf); + tty_buffer_free_all(tty); + kfree(tty); +} + +#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; + + 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; +} + +/** + * 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; + + 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; + if (*str == ',') + str++; + if (*str == '\0') + str = NULL; + + if (tty_line >= 0 && tty_line <= p->num && p->ops && + p->ops->poll_init && !p->ops->poll_init(p, tty_line, str)) { + 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(&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->ops->flush_buffer) + ld->ops->flush_buffer(tty); + tty_ldisc_deref(ld); + } + tty_buffer_flush(tty); +} + +EXPORT_SYMBOL_GPL(tty_ldisc_flush); + +/** + * tty_reset_termios - reset terminal state + * @tty: tty to reset + * + * Restore a terminal to the driver default state + */ + +static void tty_reset_termios(struct tty_struct *tty) +{ + mutex_lock(&tty->termios_mutex); + *tty->termios = tty->driver->init_termios; + tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios); + tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios); + mutex_unlock(&tty->termios_mutex); +} + +/** + * do_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: + * BKL + * 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 + */ +static void do_tty_hangup(struct work_struct *work) +{ + struct tty_struct *tty = + container_of(work, struct tty_struct, hangup_work); + struct file *cons_filp = NULL; + struct file *filp, *f = NULL; + struct task_struct *p; + struct tty_ldisc *ld; + int closecount = 0, n; + unsigned long flags; + int refs = 0; + + 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_u.fu_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->ops->flush_buffer) + ld->ops->flush_buffer(tty); + tty_driver_flush_buffer(tty); + if ((test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) && + ld->ops->write_wakeup) + ld->ops->write_wakeup(tty); + if (ld->ops->hangup) + ld->ops->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) + tty_reset_termios(tty); + /* 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) { + 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); + tty->flags = 0; + 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); + if (ld) { + tty_ldisc_enable(tty); + tty_ldisc_deref(ld); + } + unlock_kernel(); + if (f) + fput(f); +} + +/** + * 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 + do_tty_hangup(&tty->hangup_work); +} + +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: + * BKL is taken for hysterical raisins + * 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; + + + tty = get_current_tty(); + if (tty) { + tty_pgrp = get_pid(tty->pgrp); + lock_kernel(); + if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY) + tty_vhangup(tty); + unlock_kernel(); + 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; + lock_kernel(); + if (tsk->signal->leader) + disassociate_ctty(0); + unlock_kernel(); + 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(&tty->link->read_wait); + } + 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(&tty->link->read_wait); + } + 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 tty_struct *tty; + struct inode *inode; + struct tty_ldisc *ld; + + tty = (struct tty_struct *)file->private_data; + inode = file->f_path.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); + 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) +{ + mutex_unlock(&tty->atomic_write_lock); + wake_up_interruptible(&tty->write_wait); +} + +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) { + 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 BKL and test the CLOSING flag for the moment. + */ + +void tty_write_message(struct tty_struct *tty, char *msg) +{ + lock_kernel(); + if (tty) { + mutex_lock(&tty->atomic_write_lock); + if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags)) + tty->ops->write(tty, msg, strlen(msg)); + tty_write_unlock(tty); + } + unlock_kernel(); + 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 involked in parallel for each device + * The line discipline write method is called under the big + * kernel lock for historical reasons. New code should not rely on this. + */ + +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_path.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->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 + */ +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; +} + +/** + * 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; + + if (driver->ops->install) + return driver->ops->install(driver, tty); + + 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 + */ +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. + * + * 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)) + 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?? */ + + WARN_ON(!test_bit(TTY_LDISC, &tty->flags)); + + 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) + goto fail_no_mem; + initialize_tty_struct(tty, driver, idx); + + retval = tty_driver_install_tty(driver, tty); + if (retval < 0) { + free_tty_struct(tty); + module_put(driver->owner); + return ERR_PTR(retval); + } + + /* + * 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 release_mem_out; + return tty; + +fail_no_mem: + module_put(driver->owner); + return ERR_PTR(-ENOMEM); + + /* call the tty release_tty routine to clean out this slot */ +release_mem_out: + if (printk_ratelimit()) + printk(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. + */ +static void release_one_tty(struct kref *kref) +{ + struct tty_struct *tty = container_of(kref, struct tty_struct, kref); + struct tty_driver *driver = tty->driver; + + if (tty->ops->shutdown) + tty->ops->shutdown(tty); + else + tty_shutdown(tty); + tty->magic = 0; + tty_driver_kref_put(driver); + module_put(driver->owner); + + file_list_lock(); + list_del_init(&tty->tty_files); + file_list_unlock(); + + free_tty_struct(tty); +} + +/** + * 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, 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); +} + +/* + * 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. + */ +void tty_release_dev(struct file *filp) +{ + struct tty_struct *tty, *o_tty; + int pty_master, tty_closing, o_tty_closing, do_sleep; + int devpts; + int idx; + char buf[64]; + struct inode *inode; + + inode = filp->f_path.dentry->d_inode; + tty = (struct tty_struct *)filp->private_data; + if (tty_paranoia_check(tty, inode, "tty_release_dev")) + return; + + 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); + return; + } + if (!devpts) { + if (tty != tty->driver->ttys[idx]) { + printk(KERN_DEBUG "tty_release_dev: driver.table[%d] not tty " + "for (%s)\n", idx, tty->name); + return; + } + if (tty->termios != tty->driver->termios[idx]) { + printk(KERN_DEBUG "tty_release_dev: driver.termios[%d] not termios " + "for (%s)\n", + idx, tty->name); + return; + } + } +#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]) { + printk(KERN_DEBUG "tty_release_dev: other->table[%d] " + "not o_tty for (%s)\n", + idx, tty->name); + return; + } + if (o_tty->termios != tty->driver->other->termios[idx]) { + printk(KERN_DEBUG "tty_release_dev: other->termios[%d] " + "not o_termios for (%s)\n", + idx, tty->name); + return; + } + if (o_tty->link != tty) { + printk(KERN_DEBUG "tty_release_dev: bad pty pointers\n"); + return; + } + } +#endif + if (tty->ops->close) + tty->ops->close(tty, filp); + + /* + * 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_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(&tty->read_wait); + do_sleep++; + } + if (waitqueue_active(&tty->write_wait)) { + wake_up(&tty->write_wait); + do_sleep++; + } + } + if (o_tty_closing) { + if (waitqueue_active(&o_tty->read_wait)) { + wake_up(&o_tty->read_wait); + do_sleep++; + } + if (waitqueue_active(&o_tty->write_wait)) { + wake_up(&o_tty->write_wait); + do_sleep++; + } + } + if (!do_sleep) + break; + + printk(KERN_WARNING "tty_release_dev: %s: read/write wait queue " + "active!\n", tty_name(tty, buf)); + 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. + */ + file_kill(filp); + filp->private_data = NULL; + + /* + * 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)) + return; + +#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_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 short 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); + + if (device == MKDEV(TTYAUX_MAJOR, 0)) { + tty = get_current_tty(); + if (!tty) { + 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; + } + } + mutex_unlock(&tty_mutex); + return -ENODEV; + } + + driver = get_tty_driver(device, &index); + if (!driver) { + 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)) + 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)) + return PTR_ERR(tty); + + filp->private_data = tty; + file_move(filp, &tty->tty_files); + 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 (!retval) { + 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_release_dev(filp); + if (retval != -ERESTARTSYS) + return retval; + if (signal_pending(current)) + return retval; + schedule(); + /* + * Need to reset f_op in case a hangup happened. + */ + if (filp->f_op == &hung_up_tty_fops) + filp->f_op = &tty_fops; + goto retry_open; + } + + mutex_lock(&tty_mutex); + spin_lock_irq(¤t->sighand->siglock); + if (!noctty && + current->signal->leader && + !current->signal->tty && + tty->session == NULL) + __proc_set_tty(current, tty); + spin_unlock_irq(¤t->sighand->siglock); + mutex_unlock(&tty_mutex); + return 0; +} + +/* BKL pushdown: scary code avoidance wrapper */ +static int tty_open(struct inode *inode, struct file *filp) +{ + int ret; + + lock_kernel(); + ret = __tty_open(inode, filp); + unlock_kernel(); + return ret; +} + + + + +/** + * 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 + */ + +static int tty_release(struct inode *inode, struct file *filp) +{ + lock_kernel(); + tty_release_dev(filp); + unlock_kernel(); + 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; + struct tty_ldisc *ld; + int ret = 0; + + tty = (struct tty_struct *)filp->private_data; + if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll")) + return 0; + + ld = tty_ldisc_ref_wait(tty); + 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; + unsigned long flags; + int retval = 0; + + lock_kernel(); + tty = (struct tty_struct *)filp->private_data; + if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "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; + if (!waitqueue_active(&tty->read_wait)) + tty->minimum_to_wake = 1; + spin_lock_irqsave(&tty->ctrl_lock, flags); + if (tty->pgrp) { + pid = tty->pgrp; + type = PIDTYPE_PGID; + } else { + pid = task_pid(current); + type = PIDTYPE_PID; + } + spin_unlock_irqrestore(&tty->ctrl_lock, flags); + retval = __f_setown(filp, pid, type, 0); + if (retval) + goto out; + } else { + if (!tty->fasync && !waitqueue_active(&tty->read_wait)) + tty->minimum_to_wake = N_TTY_BUF_SIZE; + } + retval = 0; +out: + unlock_kernel(); + 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_ldisc_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; + ld = tty_ldisc_ref_wait(tty); + 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->termios_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->termios_mutex); + err = copy_to_user(arg, &tty->winsize, sizeof(*arg)); + mutex_unlock(&tty->termios_mutex); + + return err ? -EFAULT: 0; +} + +/** + * tty_do_resize - resize event + * @tty: tty being resized + * @real_tty: real tty (not the same as tty if using a pty/tty pair) + * @rows: rows (character) + * @cols: cols (character) + * + * Update the termios variables and send the neccessary signals to + * peform a terminal resize correctly + */ + +int tty_do_resize(struct tty_struct *tty, struct tty_struct *real_tty, + struct winsize *ws) +{ + struct pid *pgrp, *rpgrp; + unsigned long flags; + + /* For a PTY we need to lock the tty side */ + mutex_lock(&real_tty->termios_mutex); + if (!memcmp(ws, &real_tty->winsize, sizeof(*ws))) + goto done; + /* Get the PID values and reference them so we can + avoid holding the tty ctrl lock while sending signals */ + spin_lock_irqsave(&tty->ctrl_lock, flags); + pgrp = get_pid(tty->pgrp); + rpgrp = get_pid(real_tty->pgrp); + spin_unlock_irqrestore(&tty->ctrl_lock, flags); + + if (pgrp) + kill_pgrp(pgrp, SIGWINCH, 1); + if (rpgrp != pgrp && rpgrp) + kill_pgrp(rpgrp, SIGWINCH, 1); + + put_pid(pgrp); + put_pid(rpgrp); + + tty->winsize = *ws; + real_tty->winsize = *ws; +done: + mutex_unlock(&real_tty->termios_mutex); + return 0; +} + +/** + * tiocswinsz - implement window size set ioctl + * @tty; 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 dependant. 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 tty_struct *real_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, real_tty, &tmp_ws); + else + return tty_do_resize(tty, real_tty, &tmp_ws); +} + +/** + * tioccons - allow admin to move logical console + * @file: the file to become console + * + * Allow the adminstrator 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; + } + get_file(file); + redirect = 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 fle 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; + + /* file->f_flags is still BKL protected in the fs layer - vomit */ + lock_kernel(); + if (nonblock) + file->f_flags |= O_NONBLOCK; + else + file->f_flags &= ~O_NONBLOCK; + unlock_kernel(); + return 0; +} + +/** + * tiocsctty - set controlling tty + * @tty: tty structure + * @arg: user argument + * + * This ioctl is used to manage job control. It permits a session + * leader to set this tty as the controlling tty for the session. + * + * Locking: + * Takes tty_mutex() to protect tty instance + * Takes tasklist_lock internally to walk sessions + * Takes ->siglock() when updating signal->tty + */ + +static int tiocsctty(struct tty_struct *tty, int arg) +{ + int ret = 0; + if (current->signal->leader && (task_session(current) == tty->session)) + return ret; + + mutex_lock(&tty_mutex); + /* + * The process must be a session leader and + * not have a controlling tty already. + */ + if (!current->signal->leader || current->signal->tty) { + ret = -EPERM; + goto unlock; + } + + if (tty->session) { + /* + * This tty is already the controlling + * tty for another session group! + */ + if (arg == 1 && capable(CAP_SYS_ADMIN)) { + /* + * Steal it away + */ + read_lock(&tasklist_lock); + session_clear_tty(tty->session); + read_unlock(&tasklist_lock); + } else { + ret = -EPERM; + goto unlock; + } + } + proc_set_tty(current, tty); +unlock: + mutex_unlock(&tty_mutex); + return ret; +} + +/** + * tty_get_pgrp - return a ref counted pgrp pid + * @tty: tty to read + * + * Returns a refcounted instance of the pid struct for the process + * group controlling the tty. + */ + +struct pid *tty_get_pgrp(struct tty_struct *tty) +{ + unsigned long flags; + struct pid *pgrp; + + spin_lock_irqsave(&tty->ctrl_lock, flags); + pgrp = get_pid(tty->pgrp); + spin_unlock_irqrestore(&tty->ctrl_lock, flags); + + return pgrp; +} +EXPORT_SYMBOL_GPL(tty_get_pgrp); + +/** + * tiocgpgrp - get process group + * @tty: tty passed by user + * @real_tty: tty side of the tty pased by the user if a pty else the tty + * @p: returned pid + * + * Obtain the process group of the tty. If there is no process group + * return an error. + * + * Locking: none. Reference to current->signal->tty is safe. + */ + +static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) +{ + struct pid *pid; + int ret; + /* + * (tty == real_tty) is a cheap way of + * testing if the tty is NOT a master pty. + */ + if (tty == real_tty && current->signal->tty != real_tty) + return -ENOTTY; + pid = tty_get_pgrp(real_tty); + ret = put_user(pid_vnr(pid), p); + put_pid(pid); + return ret; +} + +/** + * tiocspgrp - attempt to set process group + * @tty: tty passed by user + * @real_tty: tty side device matching tty passed by user + * @p: pid pointer + * + * Set the process group of the tty to the session passed. Only + * permitted where the tty session is our session. + * + * Locking: RCU, ctrl lock + */ + +static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) +{ + struct pid *pgrp; + pid_t pgrp_nr; + int retval = tty_check_change(real_tty); + unsigned long flags; + + if (retval == -EIO) + return -ENOTTY; + if (retval) + return retval; + if (!current->signal->tty || + (current->signal->tty != real_tty) || + (real_tty->session != task_session(current))) + return -ENOTTY; + if (get_user(pgrp_nr, p)) + return -EFAULT; + if (pgrp_nr < 0) + return -EINVAL; + rcu_read_lock(); + pgrp = find_vpid(pgrp_nr); + retval = -ESRCH; + if (!pgrp) + goto out_unlock; + retval = -EPERM; + if (session_of_pgrp(pgrp) != task_session(current)) + goto out_unlock; + retval = 0; + spin_lock_irqsave(&tty->ctrl_lock, flags); + put_pid(real_tty->pgrp); + real_tty->pgrp = get_pid(pgrp); + spin_unlock_irqrestore(&tty->ctrl_lock, flags); +out_unlock: + rcu_read_unlock(); + return retval; +} + +/** + * tiocgsid - get session id + * @tty: tty passed by user + * @real_tty: tty side of the tty pased by the user if a pty else the tty + * @p: pointer to returned session id + * + * Obtain the session id of the tty. If there is no session + * return an error. + * + * Locking: none. Reference to current->signal->tty is safe. + */ + +static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) +{ + /* + * (tty == real_tty) is a cheap way of + * testing if the tty is NOT a master pty. + */ + if (tty == real_tty && current->signal->tty != real_tty) + return -ENOTTY; + if (!real_tty->session) + return -ENOTTY; + return put_user(pid_vnr(real_tty->session), p); +} + +/** + * 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 ldisc; + int ret; + + if (get_user(ldisc, p)) + return -EFAULT; + + lock_kernel(); + ret = tty_set_ldisc(tty, ldisc); + unlock_kernel(); + + 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, struct file *file, int __user *p) +{ + int retval = -EINVAL; + + if (tty->ops->tiocmget) { + retval = tty->ops->tiocmget(tty, file); + + if (retval >= 0) + retval = put_user(retval, p); + } + return retval; +} + +/** + * tty_tiocmset - set modem status + * @tty: tty device + * @file: user file pointer + * @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, struct file *file, 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, file, set, clear); +} + +/* + * 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, *real_tty; + void __user *p = (void __user *)arg; + int retval; + struct tty_ldisc *ld; + struct inode *inode = file->f_dentry->d_inode; + + tty = (struct tty_struct *)file->private_data; + if (tty_paranoia_check(tty, inode, "tty_ioctl")) + return -EINVAL; + + real_tty = tty; + if (tty->driver->type == TTY_DRIVER_TYPE_PTY && + tty->driver->subtype == PTY_TYPE_MASTER) + real_tty = tty->link; + + + /* + * 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(tty, 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 TIOCNOTTY: + if (current->signal->tty != tty) + return -ENOTTY; + no_tty(); + return 0; + case TIOCSCTTY: + return tiocsctty(tty, arg); + case TIOCGPGRP: + return tiocgpgrp(tty, real_tty, p); + case TIOCSPGRP: + return tiocspgrp(tty, real_tty, p); + case TIOCGSID: + return tiocgsid(tty, real_tty, p); + case TIOCGETD: + return put_user(tty->ldisc.ops->num, (int __user *)p); + case TIOCSETD: + return tiocsetd(tty, 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, file, p); + case TIOCMSET: + case TIOCMBIC: + case TIOCMBIS: + return tty_tiocmset(tty, file, cmd, p); + case TCFLSH: + switch (arg) { + case TCIFLUSH: + case TCIOFLUSH: + /* flush tty buffer and allow ldisc to process ioctl */ + tty_buffer_flush(tty); + break; + } + break; + } + if (tty->ops->ioctl) { + retval = (tty->ops->ioctl)(tty, file, cmd, arg); + if (retval != -ENOIOCTLCMD) + return retval; + } + ld = tty_ldisc_ref_wait(tty); + retval = -EINVAL; + if (ld->ops->ioctl) { + retval = ld->ops->ioctl(tty, file, cmd, arg); + if (retval == -ENOIOCTLCMD) + retval = -EINVAL; + } + tty_ldisc_deref(ld); + return retval; +} + +#ifdef CONFIG_COMPAT +static long tty_compat_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + struct inode *inode = file->f_dentry->d_inode; + struct tty_struct *tty = file->private_data; + struct tty_ldisc *ld; + int retval = -ENOIOCTLCMD; + + if (tty_paranoia_check(tty, inode, "tty_ioctl")) + return -EINVAL; + + if (tty->ops->compat_ioctl) { + retval = (tty->ops->compat_ioctl)(tty, file, cmd, arg); + if (retval != -ENOIOCTLCMD) + return retval; + } + + ld = tty_ldisc_ref_wait(tty); + if (ld->ops->compat_ioctl) + retval = ld->ops->compat_ioctl(tty, file, cmd, arg); + tty_ldisc_deref(ld); + + return retval; +} +#endif + +/* + * 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; + struct file *filp; + struct fdtable *fdt; + + 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) { + printk(KERN_NOTICE "SAK: killed process %d" + " (%s): task_session_nr(p)==tty->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) { + printk(KERN_NOTICE "SAK: killed process %d" + " (%s): task_session_nr(p)==tty->session\n", + task_pid_nr(p), p->comm); + send_sig(SIGKILL, p, 1); + continue; + } + task_lock(p); + if (p->files) { + /* + * We don't take a ref to the file, so we must + * hold ->file_lock instead. + */ + spin_lock(&p->files->file_lock); + fdt = files_fdtable(p->files); + for (i = 0; i < fdt->max_fds; i++) { + filp = fcheck_files(p->files, i); + if (!filp) + continue; + if (filp->f_op->read == tty_read && + filp->private_data == tty) { + printk(KERN_NOTICE "SAK: killed process %d" + " (%s): fd#%d opened to the tty\n", + task_pid_nr(p), p->comm, i); + force_sig(SIGKILL, p); + break; + } + } + spin_unlock(&p->files->file_lock); + } + 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); + +/** + * initialize_tty_struct + * @tty: tty to initialize + * + * This subroutine initializes a tty structure that has been newly + * allocated. + * + * Locking: none - tty in question must not be exposed at this point + */ + +void initialize_tty_struct(struct tty_struct *tty, + struct tty_driver *driver, int idx) +{ + memset(tty, 0, sizeof(struct tty_struct)); + kref_init(&tty->kref); + tty->magic = TTY_MAGIC; + tty_ldisc_init(tty); + tty->session = NULL; + tty->pgrp = NULL; + tty->overrun_time = jiffies; + tty->buf.head = tty->buf.tail = NULL; + tty_buffer_init(tty); + mutex_init(&tty->termios_mutex); + init_waitqueue_head(&tty->write_wait); + init_waitqueue_head(&tty->read_wait); + INIT_WORK(&tty->hangup_work, do_tty_hangup); + mutex_init(&tty->atomic_read_lock); + mutex_init(&tty->atomic_write_lock); + spin_lock_init(&tty->read_lock); + spin_lock_init(&tty->ctrl_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_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; + +/** + * 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) +{ + char name[64]; + dev_t dev = MKDEV(driver->major, driver->minor_start) + index; + + if (index >= driver->num) { + printk(KERN_ERR "Attempt to register invalid tty line number " + " (%d).\n", 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); + + return device_create(tty_class, device, dev, NULL, name); +} +EXPORT_SYMBOL(tty_register_device); + +/** + * 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); +} +EXPORT_SYMBOL(tty_unregister_device); + +struct tty_driver *alloc_tty_driver(int lines) +{ + struct tty_driver *driver; + + driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL); + if (driver) { + kref_init(&driver->kref); + driver->magic = TTY_DRIVER_MAGIC; + driver->num = lines; + /* later we'll move allocation of tables here */ + } + return driver; +} +EXPORT_SYMBOL(alloc_tty_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; + void *p; + + if (driver->flags & TTY_DRIVER_INSTALLED) { + /* + * Free the termios and termios_locked structures because + * we don't want to get memory leaks when modular tty + * drivers are removed from the kernel. + */ + 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); + } + p = driver->ttys; + proc_tty_unregister_driver(driver); + driver->ttys = NULL; + driver->termios = NULL; + kfree(p); + cdev_del(&driver->cdev); + } + 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; + void **p = NULL; + + if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM) && driver->num) { + p = kzalloc(driver->num * 2 * sizeof(void *), GFP_KERNEL); + if (!p) + return -ENOMEM; + } + + 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) { + kfree(p); + return error; + } + + if (p) { + driver->ttys = (struct tty_struct **)p; + driver->termios = (struct ktermios **)(p + driver->num); + } else { + driver->ttys = NULL; + driver->termios = NULL; + } + + cdev_init(&driver->cdev, &tty_fops); + driver->cdev.owner = driver->owner; + error = cdev_add(&driver->cdev, dev, driver->num); + if (error) { + unregister_chrdev_region(dev, driver->num); + driver->ttys = NULL; + driver->termios = NULL; + kfree(p); + return error; + } + + 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++) + tty_register_device(driver, i, NULL); + } + proc_tty_register_driver(driver); + driver->flags |= TTY_DRIVER_INSTALLED; + return 0; +} + +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 proc_clear_tty(struct task_struct *p) +{ + unsigned long flags; + struct tty_struct *tty; + spin_lock_irqsave(&p->sighand->siglock, flags); + tty = p->signal->tty; + p->signal->tty = NULL; + spin_unlock_irqrestore(&p->sighand->siglock, flags); + tty_kref_put(tty); +} + +/* Called under the sighand lock */ + +static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty) +{ + if (tty) { + unsigned long flags; + /* We should not have a session or pgrp to put here but.... */ + spin_lock_irqsave(&tty->ctrl_lock, flags); + put_pid(tty->session); + put_pid(tty->pgrp); + tty->pgrp = get_pid(task_pgrp(tsk)); + spin_unlock_irqrestore(&tty->ctrl_lock, flags); + tty->session = get_pid(task_session(tsk)); + if (tsk->signal->tty) { + printk(KERN_DEBUG "tty not NULL!!\n"); + tty_kref_put(tsk->signal->tty); + } + } + put_pid(tsk->signal->tty_old_pgrp); + tsk->signal->tty = tty_kref_get(tty); + tsk->signal->tty_old_pgrp = NULL; +} + +static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty) +{ + spin_lock_irq(&tsk->sighand->siglock); + __proc_set_tty(tsk, tty); + spin_unlock_irq(&tsk->sighand->siglock); +} + +struct tty_struct *get_current_tty(void) +{ + struct tty_struct *tty; + unsigned long flags; + + spin_lock_irqsave(¤t->sighand->siglock, flags); + tty = tty_kref_get(current->signal->tty); + spin_unlock_irqrestore(¤t->sighand->siglock, flags); + return tty; +} +EXPORT_SYMBOL_GPL(get_current_tty); + +void tty_default_fops(struct file_operations *fops) +{ + *fops = tty_fops; +} + +/* + * Initialize the console device. This is called *early*, so + * we can't necessarily depend on lots of kernel help here. + * Just do some early initializations, and do the complex setup + * later. + */ +void __init console_init(void) +{ + initcall_t *call; + + /* Setup the default TTY line discipline. */ + tty_ldisc_begin(); + + /* + * set up the console device so that later boot sequences can + * inform about problems etc.. + */ + call = __con_initcall_start; + while (call < __con_initcall_end) { + (*call)(); + call++; + } +} + +static int __init tty_class_init(void) +{ + tty_class = class_create(THIS_MODULE, "tty"); + if (IS_ERR(tty_class)) + return PTR_ERR(tty_class); + return 0; +} + +postcore_initcall(tty_class_init); + +/* 3/2004 jmc: why do these devices exist? */ + +static struct cdev tty_cdev, console_cdev; + +/* + * Ok, now we can initialize the rest of the tty devices and can count + * on memory allocations, interrupts etc.. + */ +static 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"); + device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL, + "console"); + +#ifdef CONFIG_VT + vty_init(&console_fops); +#endif + return 0; +} +module_init(tty_init); |
