| /* |
| * 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 <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 |
| #ifdef TTY_DEBUG_HANGUP |
| # define tty_debug_hangup(tty, f, args...) tty_debug(tty, f, ##args) |
| #else |
| # define tty_debug_hangup(tty, f, args...) do { } while (0) |
| #endif |
| |
| #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, |
| /* .c_line = N_TTY, */ |
| }; |
| |
| 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 */ |
| DEFINE_MUTEX(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 *); |
| 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); |
| |
| /** |
| * 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 |
| */ |
| |
| static void free_tty_struct(struct tty_struct *tty) |
| { |
| tty_ldisc_deinit(tty); |
| put_device(tty->dev); |
| kfree(tty->write_buf); |
| tty->magic = 0xDEADDEAD; |
| kfree(tty); |
| } |
| |
| static inline struct tty_struct *file_tty(struct file *file) |
| { |
| return ((struct tty_file_private *)file->private_data)->tty; |
| } |
| |
| int tty_alloc_file(struct file *file) |
| { |
| struct tty_file_private *priv; |
| |
| priv = kmalloc(sizeof(*priv), GFP_KERNEL); |
| if (!priv) |
| return -ENOMEM; |
| |
| file->private_data = priv; |
| |
| return 0; |
| } |
| |
| /* Associate a new file with the tty structure */ |
| void tty_add_file(struct tty_struct *tty, struct file *file) |
| { |
| struct tty_file_private *priv = file->private_data; |
| |
| priv->tty = tty; |
| priv->file = file; |
| |
| spin_lock(&tty->files_lock); |
| list_add(&priv->list, &tty->tty_files); |
| spin_unlock(&tty->files_lock); |
| } |
| |
| /** |
| * tty_free_file - free file->private_data |
| * |
| * This shall be used only for fail path handling when tty_add_file was not |
| * called yet. |
| */ |
| void tty_free_file(struct file *file) |
| { |
| struct tty_file_private *priv = file->private_data; |
| |
| file->private_data = NULL; |
| kfree(priv); |
| } |
| |
| /* Delete file from its tty */ |
| static void tty_del_file(struct file *file) |
| { |
| struct tty_file_private *priv = file->private_data; |
| struct tty_struct *tty = priv->tty; |
| |
| spin_lock(&tty->files_lock); |
| list_del(&priv->list); |
| spin_unlock(&tty->files_lock); |
| tty_free_file(file); |
| } |
| |
| |
| #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base) |
| |
| /** |
| * tty_name - return tty naming |
| * @tty: tty structure |
| * |
| * 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 |
| */ |
| |
| const char *tty_name(const struct tty_struct *tty) |
| { |
| if (!tty) /* Hmm. NULL pointer. That's fun. */ |
| return "NULL tty"; |
| return tty->name; |
| } |
| |
| EXPORT_SYMBOL(tty_name); |
| |
| const char *tty_driver_name(const struct tty_struct *tty) |
| { |
| if (!tty || !tty->driver) |
| return ""; |
| return tty->driver->name; |
| } |
| |
| static int tty_paranoia_check(struct tty_struct *tty, struct inode *inode, |
| const char *routine) |
| { |
| #ifdef TTY_PARANOIA_CHECK |
| if (!tty) { |
| pr_warn("(%d:%d): %s: NULL tty\n", |
| imajor(inode), iminor(inode), routine); |
| return 1; |
| } |
| if (tty->magic != TTY_MAGIC) { |
| pr_warn("(%d:%d): %s: bad magic number\n", |
| imajor(inode), iminor(inode), routine); |
| return 1; |
| } |
| #endif |
| return 0; |
| } |
| |
| /* Caller must hold tty_lock */ |
| 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) { |
| tty_warn(tty, "%s: tty->count(%d) != #fd's(%d)\n", |
| routine, tty->count, count); |
| 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 |
| |
| static int is_ignored(int sig) |
| { |
| return (sigismember(¤t->blocked, sig) || |
| current->sighand->action[sig-1].sa.sa_handler == SIG_IGN); |
| } |
| |
| /** |
| * 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, int sig) |
| { |
| unsigned long flags; |
| struct pid *pgrp, *tty_pgrp; |
| int ret = 0; |
| |
| if (current->signal->tty != tty) |
| return 0; |
| |
| rcu_read_lock(); |
| pgrp = task_pgrp(current); |
| |
| spin_lock_irqsave(&tty->ctrl_lock, flags); |
| tty_pgrp = tty->pgrp; |
| spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
| |
| if (tty_pgrp && pgrp != tty->pgrp) { |
| if (is_ignored(sig)) { |
| if (sig == SIGTTIN) |
| ret = -EIO; |
| } else if (is_current_pgrp_orphaned()) |
| ret = -EIO; |
| else { |
| kill_pgrp(pgrp, sig, 1); |
| set_thread_flag(TIF_SIGPENDING); |
| ret = -ERESTARTSYS; |
| } |
| } |
| rcu_read_unlock(); |
| |
| if (!tty_pgrp) |
| tty_warn(tty, "sig=%d, tty->pgrp == NULL!\n", sig); |
| |
| return ret; |
| } |
| |
| int tty_check_change(struct tty_struct *tty) |
| { |
| return __tty_check_change(tty, SIGTTOU); |
| } |
| 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 int hung_up_tty_fasync(int fd, struct file *file, int on) |
| { |
| return -ENOTTY; |
| } |
| |
| 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, |
| .fasync = hung_up_tty_fasync, |
| }; |
| |
| static DEFINE_SPINLOCK(redirect_lock); |
| static struct file *redirect; |
| |
| |
| 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); |
| } |
| |
| /** |
| * proc_set_tty - set the controlling terminal |
| * |
| * Only callable by the session leader and only if it does not already have |
| * a controlling terminal. |
| * |
| * Caller must hold: tty_lock() |
| * a readlock on tasklist_lock |
| * sighand lock |
| */ |
| static void __proc_set_tty(struct tty_struct *tty) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&tty->ctrl_lock, flags); |
| /* |
| * The session and fg pgrp references will be non-NULL if |
| * tiocsctty() is stealing the controlling tty |
| */ |
| put_pid(tty->session); |
| put_pid(tty->pgrp); |
| tty->pgrp = get_pid(task_pgrp(current)); |
| spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
| tty->session = get_pid(task_session(current)); |
| if (current->signal->tty) { |
| tty_debug(tty, "current tty %s not NULL!!\n", |
| current->signal->tty->name); |
| tty_kref_put(current->signal->tty); |
| } |
| put_pid(current->signal->tty_old_pgrp); |
| current->signal->tty = tty_kref_get(tty); |
| current->signal->tty_old_pgrp = NULL; |
| } |
| |
| static void proc_set_tty(struct tty_struct *tty) |
| { |
| spin_lock_irq(¤t->sighand->siglock); |
| __proc_set_tty(tty); |
| spin_unlock_irq(¤t->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); |
| |
| 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); |
| } |
| |
| /** |
| * 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_signal_session_leader - sends SIGHUP to session leader |
| * @tty controlling tty |
| * @exit_session if non-zero, signal all foreground group processes |
| * |
| * Send SIGHUP and SIGCONT to the session leader and its process group. |
| * Optionally, signal all processes in the foreground process group. |
| * |
| * Returns the number of processes in the session with this tty |
| * as their controlling terminal. This value is used to drop |
| * tty references for those processes. |
| */ |
| static int tty_signal_session_leader(struct tty_struct *tty, int exit_session) |
| { |
| struct task_struct *p; |
| int refs = 0; |
| struct pid *tty_pgrp = NULL; |
| |
| 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(&tty->ctrl_lock); |
| tty_pgrp = get_pid(tty->pgrp); |
| if (tty->pgrp) |
| p->signal->tty_old_pgrp = get_pid(tty->pgrp); |
| spin_unlock(&tty->ctrl_lock); |
| spin_unlock_irq(&p->sighand->siglock); |
| } while_each_pid_task(tty->session, PIDTYPE_SID, p); |
| } |
| read_unlock(&tasklist_lock); |
| |
| if (tty_pgrp) { |
| if (exit_session) |
| kill_pgrp(tty_pgrp, SIGHUP, exit_session); |
| put_pid(tty_pgrp); |
| } |
| |
| return refs; |
| } |
| |
| /** |
| * __tty_hangup - actual handler for hangup events |
| * @work: tty device |
| * |
| * This can be called by a "kworker" 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_ldiscs_lock from called functions |
| * termios_rwsem resetting termios data |
| * tasklist_lock to walk task list for hangup event |
| * ->siglock to protect ->signal/->sighand |
| */ |
| static void __tty_hangup(struct tty_struct *tty, int exit_session) |
| { |
| struct file *cons_filp = NULL; |
| struct file *filp, *f = NULL; |
| struct tty_file_private *priv; |
| int closecount = 0, n; |
| int refs; |
| |
| if (!tty) |
| return; |
| |
| |
| spin_lock(&redirect_lock); |
| if (redirect && file_tty(redirect) == tty) { |
| f = redirect; |
| redirect = NULL; |
| } |
| spin_unlock(&redirect_lock); |
| |
| tty_lock(tty); |
| |
| if (test_bit(TTY_HUPPED, &tty->flags)) { |
| tty_unlock(tty); |
| return; |
| } |
| |
| /* inuse_filps is protected by the single tty lock, |
| this really needs to change if we want to flush the |
| workqueue with the lock held */ |
| check_tty_count(tty, "tty_hangup"); |
| |
| spin_lock(&tty->files_lock); |
| /* This breaks for file handles being sent over AF_UNIX sockets ? */ |
| list_for_each_entry(priv, &tty->tty_files, list) { |
| filp = priv->file; |
| if (filp->f_op->write == redirected_tty_write) |
| cons_filp = filp; |
| if (filp->f_op->write != tty_write) |
| continue; |
| closecount++; |
| __tty_fasync(-1, filp, 0); /* can't block */ |
| filp->f_op = &hung_up_tty_fops; |
| } |
| spin_unlock(&tty->files_lock); |
| |
| refs = tty_signal_session_leader(tty, exit_session); |
| /* Account for the p->signal references we killed */ |
| while (refs--) |
| tty_kref_put(tty); |
| |
| tty_ldisc_hangup(tty, cons_filp != NULL); |
| |
| spin_lock_irq(&tty->ctrl_lock); |
| clear_bit(TTY_THROTTLED, &tty->flags); |
| clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); |
| put_pid(tty->session); |
| put_pid(tty->pgrp); |
| tty->session = NULL; |
| tty->pgrp = NULL; |
| tty->ctrl_status = 0; |
| spin_unlock_irq(&tty->ctrl_lock); |
| |
| /* |
| * If one of the devices matches a console pointer, we |
| * cannot just call hangup() because that will cause |
| * tty->count and state->count to go out of sync. |
| * So we just call close() the right number of times. |
| */ |
| if (cons_filp) { |
| if (tty->ops->close) |
| for (n = 0; n < closecount; n++) |
| tty->ops->close(tty, cons_filp); |
| } else if (tty->ops->hangup) |
| tty->ops->hangup(tty); |
| /* |
| * We don't want to have driver/ldisc interactions beyond the ones |
| * we did here. The driver layer expects no calls after ->hangup() |
| * from the ldisc side, which is now guaranteed. |
| */ |
| set_bit(TTY_HUPPED, &tty->flags); |
| tty_unlock(tty); |
| |
| if (f) |
| fput(f); |
| } |
| |
| static void do_tty_hangup(struct work_struct *work) |
| { |
| struct tty_struct *tty = |
| container_of(work, struct tty_struct, hangup_work); |
| |
| __tty_hangup(tty, 0); |
| } |
| |
| /** |
| * tty_hangup - trigger a hangup event |
| * @tty: tty to hangup |
| * |
| * A carrier loss (virtual or otherwise) has occurred on this like |
| * schedule a hangup sequence to run after this event. |
| */ |
| |
| void tty_hangup(struct tty_struct *tty) |
| { |
| tty_debug_hangup(tty, "hangup\n"); |
| schedule_work(&tty->hangup_work); |
| } |
| |
| EXPORT_SYMBOL(tty_hangup); |
| |
| /** |
| * tty_vhangup - process vhangup |
| * @tty: tty to hangup |
| * |
| * The user has asked via system call for the terminal to be hung up. |
| * We do this synchronously so that when the syscall returns the process |
| * is complete. That guarantee is necessary for security reasons. |
| */ |
| |
| void tty_vhangup(struct tty_struct *tty) |
| { |
| tty_debug_hangup(tty, "vhangup\n"); |
| __tty_hangup(tty, 0); |
| } |
| |
| EXPORT_SYMBOL(tty_vhangup); |
| |
| |
| /** |
| * tty_vhangup_self - process vhangup for own ctty |
| * |
| * Perform a vhangup on the current controlling tty |
| */ |
| |
| void tty_vhangup_self(void) |
| { |
| struct tty_struct *tty; |
| |
| tty = get_current_tty(); |
| if (tty) { |
| tty_vhangup(tty); |
| tty_kref_put(tty); |
| } |
| } |
| |
| /** |
| * tty_vhangup_session - hangup session leader exit |
| * @tty: tty to hangup |
| * |
| * The session leader is exiting and hanging up its controlling terminal. |
| * Every process in the foreground process group is signalled SIGHUP. |
| * |
| * We do this synchronously so that when the syscall returns the process |
| * is complete. That guarantee is necessary for security reasons. |
| */ |
| |
| static void tty_vhangup_session(struct tty_struct *tty) |
| { |
| tty_debug_hangup(tty, "session hangup\n"); |
| __tty_hangup(tty, 1); |
| } |
| |
| /** |
| * tty_hung_up_p - was tty hung up |
| * @filp: file pointer of tty |
| * |
| * Return true if the tty has been subject to a vhangup or a carrier |
| * loss |
| */ |
| |
| int tty_hung_up_p(struct file *filp) |
| { |
| return (filp->f_op == &hung_up_tty_fops); |
| } |
| |
| EXPORT_SYMBOL(tty_hung_up_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; |
| |
| if (!current->signal->leader) |
| return; |
| |
| tty = get_current_tty(); |
| if (tty) { |
| if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY) { |
| tty_vhangup_session(tty); |
| } else { |
| struct pid *tty_pgrp = tty_get_pgrp(tty); |
| if (tty_pgrp) { |
| kill_pgrp(tty_pgrp, SIGHUP, on_exit); |
| if (!on_exit) |
| kill_pgrp(tty_pgrp, SIGCONT, on_exit); |
| put_pid(tty_pgrp); |
| } |
| } |
| 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; |
| } |
| |
| spin_lock_irq(¤t->sighand->siglock); |
| put_pid(current->signal->tty_old_pgrp); |
| current->signal->tty_old_pgrp = NULL; |
| |
| tty = tty_kref_get(current->signal->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 |
| tty_debug_hangup(tty, "no current tty\n"); |
| |
| spin_unlock_irq(¤t->sighand->siglock); |
| /* 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) |
| { |
| /* FIXME: Review locking here. The tty_lock never covered any race |
| between a new association and proc_clear_tty but possible we need |
| to protect against this anyway */ |
| struct task_struct *tsk = current; |
| disassociate_ctty(0); |
| proc_clear_tty(tsk); |
| } |
| |
| |
| /** |
| * stop_tty - propagate flow control |
| * @tty: tty to stop |
| * |
| * Perform flow control to the driver. May be called |
| * on an already stopped device and will not re-call the driver |
| * method. |
| * |
| * This functionality is used by both the line disciplines for |
| * halting incoming flow and by the driver. It may therefore be |
| * called from any context, may be under the tty atomic_write_lock |
| * but not always. |
| * |
| * Locking: |
| * flow_lock |
| */ |
| |
| void __stop_tty(struct tty_struct *tty) |
| { |
| if (tty->stopped) |
| return; |
| tty->stopped = 1; |
| if (tty->ops->stop) |
| tty->ops->stop(tty); |
| } |
| |
| void stop_tty(struct tty_struct *tty) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&tty->flow_lock, flags); |
| __stop_tty(tty); |
| spin_unlock_irqrestore(&tty->flow_lock, flags); |
| } |
| EXPORT_SYMBOL(stop_tty); |
| |
| /** |
| * start_tty - propagate flow control |
| * @tty: tty to start |
| * |
| * Start a tty that has been stopped if at all possible. If this |
| * tty was previous stopped and is now being started, the driver |
| * start method is invoked and the line discipline woken. |
| * |
| * Locking: |
| * flow_lock |
| */ |
| |
| void __start_tty(struct tty_struct *tty) |
| { |
| if (!tty->stopped || tty->flow_stopped) |
| return; |
| tty->stopped = 0; |
| if (tty->ops->start) |
| tty->ops->start(tty); |
| tty_wakeup(tty); |
| } |
| |
| void start_tty(struct tty_struct *tty) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&tty->flow_lock, flags); |
| __start_tty(tty); |
| spin_unlock_irqrestore(&tty->flow_lock, flags); |
| } |
| EXPORT_SYMBOL(start_tty); |
| |
| static void tty_update_time(struct timespec *time) |
| { |
| unsigned long sec = get_seconds(); |
| |
| /* |
| * We only care if the two values differ in anything other than the |
| * lower three bits (i.e every 8 seconds). If so, then we can update |
| * the time of the tty device, otherwise it could be construded as a |
| * security leak to let userspace know the exact timing of the tty. |
| */ |
| if ((sec ^ time->tv_sec) & ~7) |
| time->tv_sec = sec; |
| } |
| |
| /** |
| * tty_read - read method for tty device files |
| * @file: pointer to tty file |
| * @buf: user buffer |
| * @count: size of user buffer |
| * @ppos: unused |
| * |
| * Perform the read system call function on this terminal device. Checks |
| * for hung up devices before calling the line discipline method. |
| * |
| * Locking: |
| * Locks the line discipline internally while needed. Multiple |
| * read calls may be outstanding in parallel. |
| */ |
| |
| static ssize_t tty_read(struct file *file, char __user *buf, size_t count, |
| loff_t *ppos) |
| { |
| int i; |
| struct inode *inode = file_inode(file); |
| struct tty_struct *tty = file_tty(file); |
| struct tty_ldisc *ld; |
| |
| if (tty_paranoia_check(tty, inode, "tty_read")) |
| return -EIO; |
| if (!tty || (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) |
| return hung_up_tty_read(file, buf, count, ppos); |
| if (ld->ops->read) |
| i = ld->ops->read(tty, file, buf, count); |
| else |
| i = -EIO; |
| tty_ldisc_deref(ld); |
| |
| if (i > 0) |
| tty_update_time(&inode->i_atime); |
| |
| return i; |
| } |
| |
| static void tty_write_unlock(struct tty_struct *tty) |
| { |
| mutex_unlock(&tty->atomic_write_lock); |
| wake_up_interruptible_poll(&tty->write_wait, POLLOUT); |
| } |
| |
| static int tty_write_lock(struct tty_struct *tty, int ndelay) |
| { |
| if (!mutex_trylock(&tty->atomic_write_lock)) { |
| if (ndelay) |
| return -EAGAIN; |
| if (mutex_lock_interruptible(&tty->atomic_write_lock)) |
| return -ERESTARTSYS; |
| } |
| return 0; |
| } |
| |
| /* |
| * Split writes up in sane blocksizes to avoid |
| * denial-of-service type attacks |
| */ |
| static inline ssize_t do_tty_write( |
| ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t), |
| struct tty_struct *tty, |
| struct file *file, |
| const char __user *buf, |
| size_t count) |
| { |
| ssize_t ret, written = 0; |
| unsigned int chunk; |
| |
| ret = tty_write_lock(tty, file->f_flags & O_NDELAY); |
| if (ret < 0) |
| return ret; |
| |
| /* |
| * We chunk up writes into a temporary buffer. This |
| * simplifies low-level drivers immensely, since they |
| * don't have locking issues and user mode accesses. |
| * |
| * But if TTY_NO_WRITE_SPLIT is set, we should use a |
| * big chunk-size.. |
| * |
| * The default chunk-size is 2kB, because the NTTY |
| * layer has problems with bigger chunks. It will |
| * claim to be able to handle more characters than |
| * it actually does. |
| * |
| * FIXME: This can probably go away now except that 64K chunks |
| * are too likely to fail unless switched to vmalloc... |
| */ |
| chunk = 2048; |
| if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags)) |
| chunk = 65536; |
| if (count < chunk) |
| chunk = count; |
| |
| /* write_buf/write_cnt is protected by the atomic_write_lock mutex */ |
| if (tty->write_cnt < chunk) { |
| unsigned char *buf_chunk; |
| |
| if (chunk < 1024) |
| chunk = 1024; |
| |
| buf_chunk = kmalloc(chunk, GFP_KERNEL); |
| if (!buf_chunk) { |
| ret = -ENOMEM; |
| goto out; |
| } |
| kfree(tty->write_buf); |
| tty->write_cnt = chunk; |
| tty->write_buf = buf_chunk; |
| } |
| |
| /* Do the write .. */ |
| for (;;) { |
| size_t size = count; |
| if (size > chunk) |
| size = chunk; |
| ret = -EFAULT; |
| if (copy_from_user(tty->write_buf, buf, size)) |
| break; |
| ret = write(tty, file, tty->write_buf, size); |
| if (ret <= 0) |
| break; |
| written += ret; |
| buf += ret; |
| count -= ret; |
| if (!count) |
| break; |
| ret = -ERESTARTSYS; |
| if (signal_pending(current)) |
| break; |
| cond_resched(); |
| } |
| if (written) { |
| tty_update_time(&file_inode(file)->i_mtime); |
| ret = written; |
| } |
| out: |
| tty_write_unlock(tty); |
| return ret; |
| } |
| |
| /** |
| * tty_write_message - write a message to a certain tty, not just the console. |
| * @tty: the destination tty_struct |
| * @msg: the message to write |
| * |
| * This is used for messages that need to be redirected to a specific tty. |
| * We don't put it into the syslog queue right now maybe in the future if |
| * really needed. |
| * |
| * We must still hold the BTM and test the CLOSING flag for the moment. |
| */ |
| |
| void tty_write_message(struct tty_struct *tty, char *msg) |
| { |
| if (tty) { |
| mutex_lock(&tty->atomic_write_lock); |
| tty_lock(tty); |
| if (tty->ops->write && tty->count > 0) |
| tty->ops->write(tty, msg, strlen(msg)); |
| tty_unlock(tty); |
| tty_write_unlock(tty); |
| } |
| return; |
| } |
| |
| |
| /** |
| * tty_write - write method for tty device file |
| * @file: tty file pointer |
| * @buf: user data to write |
| * @count: bytes to write |
| * @ppos: unused |
| * |
| * Write data to a tty device via the line discipline. |
| * |
| * Locking: |
| * Locks the line discipline as required |
| * Writes to the tty driver are serialized by the atomic_write_lock |
| * and are then processed in chunks to the device. The line discipline |
| * write method will not be invoked in parallel for each device. |
| */ |
| |
| static ssize_t tty_write(struct file *file, const char __user *buf, |
| size_t count, loff_t *ppos) |
| { |
| struct tty_struct *tty = file_tty(file); |
| struct tty_ldisc *ld; |
| ssize_t ret; |
| |
| if (tty_paranoia_check(tty, file_inode(file), "tty_write")) |
| return -EIO; |
| if (!tty || !tty->ops->write || |
| (test_bit(TTY_IO_ERROR, &tty->flags))) |
| return -EIO; |
| /* Short term debug to catch buggy drivers */ |
| if (tty->ops->write_room == NULL) |
| tty_err(tty, "missing write_room method\n"); |
| ld = tty_ldisc_ref_wait(tty); |
| if (!ld) |
| return hung_up_tty_write(file, buf, count, ppos); |
| if (!ld->ops->write) |
| ret = -EIO; |
| else |
| ret = do_tty_write(ld->ops->write, tty, file, buf, count); |
| tty_ldisc_deref(ld); |
| return ret; |
| } |
| |
| ssize_t redirected_tty_write(struct file *file, const char __user *buf, |
| size_t count, loff_t *ppos) |
| { |
| struct file *p = NULL; |
| |
| spin_lock(&redirect_lock); |
| if (redirect) |
| p = get_file(redirect); |
| spin_unlock(&redirect_lock); |
| |
| if (p) { |
| ssize_t res; |
| res = vfs_write(p, buf, count, &p->f_pos); |
| fput(p); |
| return res; |
| } |
| return tty_write(file, buf, count, ppos); |
| } |
| |
| /** |
| * tty_send_xchar - send priority character |
| * |
| * Send a high priority character to the tty even if stopped |
| * |
| * Locking: none for xchar method, write ordering for write method. |
| */ |
| |
| int tty_send_xchar(struct tty_struct *tty, char ch) |
| { |
| int was_stopped = tty->stopped; |
| |
| if (tty->ops->send_xchar) { |
| down_read(&tty->termios_rwsem); |
| tty->ops->send_xchar(tty, ch); |
| up_read(&tty->termios_rwsem); |
| return 0; |
| } |
| |
| if (tty_write_lock(tty, 0) < 0) |
| return -ERESTARTSYS; |
| |
| down_read(&tty->termios_rwsem); |
| if (was_stopped) |
| start_tty(tty); |
| tty->ops->write(tty, &ch, 1); |
| if (was_stopped) |
| stop_tty(tty); |
| up_read(&tty->termios_rwsem); |
| tty_write_unlock(tty); |
| return 0; |
| } |
| |
| static char ptychar[] = "pqrstuvwxyzabcde"; |
| |
| /** |
| * pty_line_name - generate name for a pty |
| * @driver: the tty driver in use |
| * @index: the minor number |
| * @p: output buffer of at least 6 bytes |
| * |
| * Generate a name from a driver reference and write it to the output |
| * buffer. |
| * |
| * Locking: None |
| */ |
| static void pty_line_name(struct tty_driver *driver, int index, char *p) |
| { |
| int i = index + driver->name_base; |
| /* ->name is initialized to "ttyp", but "tty" is expected */ |
| sprintf(p, "%s%c%x", |
| driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name, |
| ptychar[i >> 4 & 0xf], i & 0xf); |
| } |
| |
| /** |
| * tty_line_name - generate name for a tty |
| * @driver: the tty driver in use |
| * @index: the minor number |
| * @p: output buffer of at least 7 bytes |
| * |
| * Generate a name from a driver reference and write it to the output |
| * buffer. |
| * |
| * Locking: None |
| */ |
| static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p) |
| { |
| if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE) |
| return sprintf(p, "%s", driver->name); |
| else |
| return sprintf(p, "%s%d", driver->name, |
| index + driver->name_base); |
| } |
| |
| /** |
| * tty_driver_lookup_tty() - find an existing tty, if any |
| * @driver: the driver for the tty |
| * @idx: the minor number |
| * |
| * Return the tty, if found. If not found, return NULL or ERR_PTR() if the |
| * driver lookup() method returns an error. |
| * |
| * Locking: tty_mutex must be held. If the tty is found, bump the tty kref. |
| */ |
| static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver, |
| struct inode *inode, int idx) |
| { |
| struct tty_struct *tty; |
| |
| if (driver->ops->lookup) |
| tty = driver->ops->lookup(driver, inode, idx); |
| else |
| tty = driver->ttys[idx]; |
| |
| if (!IS_ERR(tty)) |
| tty_kref_get(tty); |
| return tty; |
| } |
| |
| /** |
| * tty_init_termios - helper for termios setup |
| * @tty: the tty to set up |
| * |
| * Initialise the termios structures for this tty. Thus runs under |
| * the tty_mutex currently so we can be relaxed about ordering. |
| */ |
| |
| void tty_init_termios(struct tty_struct *tty) |
| { |
| struct ktermios *tp; |
| int idx = tty->index; |
| |
| if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) |
| tty->termios = tty->driver->init_termios; |
| else { |
| /* Check for lazy saved data */ |
| tp = tty->driver->termios[idx]; |
| if (tp != NULL) { |
| tty->termios = *tp; |
| tty->termios.c_line = tty->driver->init_termios.c_line; |
| } else |
| tty->termios = tty->driver->init_termios; |
| } |
| /* Compatibility until drivers always set this */ |
| tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios); |
| tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios); |
| } |
| EXPORT_SYMBOL_GPL(tty_init_termios); |
| |
| int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty) |
| { |
| tty_init_termios(tty); |
| tty_driver_kref_get(driver); |
| tty->count++; |
| driver->ttys[tty->index] = tty; |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(tty_standard_install); |
| |
| /** |
| * tty_driver_install_tty() - install a tty entry in the driver |
| * @driver: the driver for the tty |
| * @tty: the tty |
| * |
| * Install a tty object into the driver tables. The tty->index field |
| * will be set by the time this is called. This method is responsible |
| * for ensuring any need additional structures are allocated and |
| * configured. |
| * |
| * Locking: tty_mutex for now |
| */ |
| static int tty_driver_install_tty(struct tty_driver *driver, |
| struct tty_struct *tty) |
| { |
| return driver->ops->install ? driver->ops->install(driver, tty) : |
| tty_standard_install(driver, tty); |
| } |
| |
| /** |
| * tty_driver_remove_tty() - remove a tty from the driver tables |
| * @driver: the driver for the tty |
| * @idx: the minor number |
| * |
| * Remvoe a tty object from the driver tables. The tty->index field |
| * will be set by the time this is called. |
| * |
| * Locking: tty_mutex for now |
| */ |
| static void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty) |
| { |
| if (driver->ops->remove) |
| driver->ops->remove(driver, tty); |
| else |
| driver->ttys[tty->index] = NULL; |
| } |
| |
| /* |
| * tty_reopen() - fast re-open of an open tty |
| * @tty - the tty to open |
| * |
| * Return 0 on success, -errno on error. |
| * Re-opens on master ptys are not allowed and return -EIO. |
| * |
| * Locking: Caller must hold tty_lock |
| */ |
| static int tty_reopen(struct tty_struct *tty) |
| { |
| struct tty_driver *driver = tty->driver; |
| |
| if (driver->type == TTY_DRIVER_TYPE_PTY && |
| driver->subtype == PTY_TYPE_MASTER) |
| return -EIO; |
| |
| if (!tty->count) |
| return -EAGAIN; |
| |
| if (test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN)) |
| return -EBUSY; |
| |
| tty->count++; |
| |
| if (!tty->ldisc) |
| return tty_ldisc_reinit(tty, tty->termios.c_line); |
| |
| return 0; |
| } |
| |
| /** |
| * tty_init_dev - initialise a tty device |
| * @driver: tty driver we are opening a device on |
| * @idx: device index |
| * @ret_tty: returned tty structure |
| * |
| * Prepare a tty device. This may not be a "new" clean device but |
| * could also be an active device. The pty drivers require special |
| * handling because of this. |
| * |
| * Locking: |
| * The function is called under the tty_mutex, which |
| * protects us from the tty struct or driver itself going away. |
| * |
| * On exit the tty device has the line discipline attached and |
| * a reference count of 1. If a pair was created for pty/tty use |
| * and the other was a pty master then it too has a reference count of 1. |
| * |
| * WSH 06/09/97: Rewritten to remove races and properly clean up after a |
| * failed open. The new code protects the open with a mutex, so it's |
| * really quite straightforward. The mutex locking can probably be |
| * relaxed for the (most common) case of reopening a tty. |
| */ |
| |
| struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx) |
| { |
| struct tty_struct *tty; |
| int retval; |
| |
| /* |
| * First time open is complex, especially for PTY devices. |
| * This code guarantees that either everything succeeds and the |
| * TTY is ready for operation, or else the table slots are vacated |
| * and the allocated memory released. (Except that the termios |
| * and locked termios may be retained.) |
| */ |
| |
| if (!try_module_get(driver->owner)) |
| return ERR_PTR(-ENODEV); |
| |
| tty = alloc_tty_struct(driver, idx); |
| if (!tty) { |
| retval = -ENOMEM; |
| goto err_module_put; |
| } |
| |
| tty_lock(tty); |
| retval = tty_driver_install_tty(driver, tty); |
| if (retval < 0) |
| goto err_free_tty; |
| |
| if (!tty->port) |
| tty->port = driver->ports[idx]; |
| |
| WARN_RATELIMIT(!tty->port, |
| "%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n", |
| __func__, tty->driver->name); |
| |
| tty->port->itty = tty; |
| |
| /* |
| * Structures all installed ... call the ldisc open routines. |
| * If we fail here just call release_tty to clean up. No need |
| * to decrement the use counts, as release_tty doesn't care. |
| */ |
| retval = tty_ldisc_setup(tty, tty->link); |
| if (retval) |
| goto err_release_tty; |
| /* Return the tty locked so that it cannot vanish under the caller */ |
| return tty; |
| |
| err_free_tty: |
| tty_unlock(tty); |
| free_tty_struct(tty); |
| err_module_put: |
| module_put(driver->owner); |
| return ERR_PTR(retval); |
| |
| /* call the tty release_tty routine to clean out this slot */ |
| err_release_tty: |
| tty_unlock(tty); |
| tty_info_ratelimited(tty, "ldisc open failed (%d), clearing slot %d\n", |
| retval, idx); |
| release_tty(tty, idx); |
| return ERR_PTR(retval); |
| } |
| |
| static void tty_free_termios(struct tty_struct *tty) |
| { |
| struct ktermios *tp; |
| int idx = tty->index; |
| |
| /* If the port is going to reset then it has no termios to save */ |
| if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) |
| return; |
| |
| /* Stash the termios data */ |
| tp = tty->driver->termios[idx]; |
| if (tp == NULL) { |
| tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL); |
| if (tp == NULL) |
| return; |
| tty->driver->termios[idx] = tp; |
| } |
| *tp = tty->termios; |
| } |
| |
| /** |
| * tty_flush_works - flush all works of a tty/pty pair |
| * @tty: tty device to flush works for (or either end of a pty pair) |
| * |
| * Sync flush all works belonging to @tty (and the 'other' tty). |
| */ |
| static void tty_flush_works(struct tty_struct *tty) |
| { |
| flush_work(&tty->SAK_work); |
| flush_work(&tty->hangup_work); |
| if (tty->link) { |
| flush_work(&tty->link->SAK_work); |
| flush_work(&tty->link->hangup_work); |
| } |
| } |
| |
| /** |
| * release_one_tty - release tty structure memory |
| * @kref: kref of tty we are obliterating |
| * |
| * Releases memory associated with a tty structure, and clears out the |
| * driver table slots. This function is called when a device is no longer |
| * in use. It also gets called when setup of a device fails. |
| * |
| * Locking: |
| * takes the file list lock internally when working on the list |
| * of ttys that the driver keeps. |
| * |
| * This method gets called from a work queue so that the driver private |
| * cleanup ops can sleep (needed for USB at least) |
| */ |
| static void release_one_tty(struct work_struct *work) |
| { |
| struct tty_struct *tty = |
| container_of(work, struct tty_struct, hangup_work); |
| struct tty_driver *driver = tty->driver; |
| struct module *owner = driver->owner; |
| |
| if (tty->ops->cleanup) |
| tty->ops->cleanup(tty); |
| |
| tty->magic = 0; |
| tty_driver_kref_put(driver); |
| module_put(owner); |
| |
| spin_lock(&tty->files_lock); |
| list_del_init(&tty->tty_files); |
| spin_unlock(&tty->files_lock); |
| |
| put_pid(tty->pgrp); |
| put_pid(tty->session); |
| free_tty_struct(tty); |
| } |
| |
| static void queue_release_one_tty(struct kref *kref) |
| { |
| struct tty_struct *tty = container_of(kref, struct tty_struct, kref); |
| |
| /* The hangup queue is now free so we can reuse it rather than |
| waste a chunk of memory for each port */ |
| INIT_WORK(&tty->hangup_work, release_one_tty); |
| schedule_work(&tty->hangup_work); |
| } |
| |
| /** |
| * tty_kref_put - release a tty kref |
| * @tty: tty device |
| * |
| * Release a reference to a tty device and if need be let the kref |
| * layer destruct the object for us |
| */ |
| |
| void tty_kref_put(struct tty_struct *tty) |
| { |
| if (tty) |
| kref_put(&tty->kref, queue_release_one_tty); |
| } |
| EXPORT_SYMBOL(tty_kref_put); |
| |
| /** |
| * release_tty - release tty structure memory |
| * |
| * Release both @tty and a possible linked partner (think pty pair), |
| * and decrement the refcount of the backing module. |
| * |
| * Locking: |
| * tty_mutex |
| * takes the file list lock internally when working on the list |
| * of ttys that the driver keeps. |
| * |
| */ |
| static void release_tty(struct tty_struct *tty, int idx) |
| { |
| /* This should always be true but check for the moment */ |
| WARN_ON(tty->index != idx); |
| WARN_ON(!mutex_is_locked(&tty_mutex)); |
| if (tty->ops->shutdown) |
| tty->ops->shutdown(tty); |
| tty_free_termios(tty); |
| tty_driver_remove_tty(tty->driver, tty); |
| tty->port->itty = NULL; |
| if (tty->link) |
| tty->link->port->itty = NULL; |
| tty_buffer_cancel_work(tty->port); |
| |
| tty_kref_put(tty->link); |
| tty_kref_put(tty); |
| } |
| |
| /** |
| * tty_release_checks - check a tty before real release |
| * @tty: tty to check |
| * @o_tty: link of @tty (if any) |
| * @idx: index of the tty |
| * |
| * Performs some paranoid checking before true release of the @tty. |
| * This is a no-op unless TTY_PARANOIA_CHECK is defined. |
| */ |
| static int tty_release_checks(struct tty_struct *tty, int idx) |
| { |
| #ifdef TTY_PARANOIA_CHECK |
| if (idx < 0 || idx >= tty->driver->num) { |
| tty_debug(tty, "bad idx %d\n", idx); |
| return -1; |
| } |
| |
| /* not much to check for devpts */ |
| if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) |
| return 0; |
| |
| if (tty != tty->driver->ttys[idx]) { |
| tty_debug(tty, "bad driver table[%d] = %p\n", |
| idx, tty->driver->ttys[idx]); |
| return -1; |
| } |
| if (tty->driver->other) { |
| struct tty_struct *o_tty = tty->link; |
| |
| if (o_tty != tty->driver->other->ttys[idx]) { |
| tty_debug(tty, "bad other table[%d] = %p\n", |
| idx, tty->driver->other->ttys[idx]); |
| return -1; |
| } |
| if (o_tty->link != tty) { |
| tty_debug(tty, "bad link = %p\n", o_tty->link); |
| return -1; |
| } |
| } |
| #endif |
| return 0; |
| } |
| |
| /** |
| * tty_release - vfs callback for close |
| * @inode: inode of tty |
| * @filp: file pointer for handle to tty |
| * |
| * Called the last time each file handle is closed that references |
| * this tty. There may however be several such references. |
| * |
| * Locking: |
| * Takes bkl. See tty_release_dev |
| * |
| * Even releasing the tty structures is a tricky business.. We have |
| * to be very careful that the structures are all released at the |
| * same time, as interrupts might otherwise get the wrong pointers. |
| * |
| * WSH 09/09/97: rewritten to avoid some nasty race conditions that could |
| * lead to double frees or releasing memory still in use. |
| */ |
| |
| int tty_release(struct inode *inode, struct file *filp) |
| { |
| struct tty_struct *tty = file_tty(filp); |
| struct tty_struct *o_tty = NULL; |
| int do_sleep, final; |
| int idx; |
| long timeout = 0; |
| int once = 1; |
| |
| if (tty_paranoia_check(tty, inode, __func__)) |
| return 0; |
| |
| tty_lock(tty); |
| check_tty_count(tty, __func__); |
| |
| __tty_fasync(-1, filp, 0); |
| |
| idx = tty->index; |
| if (tty->driver->type == TTY_DRIVER_TYPE_PTY && |
| tty->driver->subtype == PTY_TYPE_MASTER) |
| o_tty = tty->link; |
| |
| if (tty_release_checks(tty, idx)) { |
| tty_unlock(tty); |
| return 0; |
| } |
| |
| tty_debug_hangup(tty, "releasing (count=%d)\n", tty->count); |
| |
| if (tty->ops->close) |
| tty->ops->close(tty, filp); |
| |
| /* If tty is pty master, lock the slave pty (stable lock order) */ |
| tty_lock_slave(o_tty); |
| |
| /* |
| * Sanity check: if tty->count is going to zero, there shouldn't be |
| * any waiters on tty->read_wait or tty->write_wait. We test the |
| * wait queues and kick everyone out _before_ actually starting to |
| * close. This ensures that we won't block while releasing the tty |
| * structure. |
| * |
| * The test for the o_tty closing is necessary, since the master and |
| * slave sides may close in any order. If the slave side closes out |
| * first, its count will be one, since the master side holds an open. |
| * Thus this test wouldn't be triggered at the time the slave closed, |
| * so we do it now. |
| */ |
| while (1) { |
| do_sleep = 0; |
| |
| if (tty->count <= 1) { |
| if (waitqueue_active(&tty->read_wait)) { |
| wake_up_poll(&tty->read_wait, POLLIN); |
| do_sleep++; |
| } |
| if (waitqueue_active(&tty->write_wait)) { |
| wake_up_poll(&tty->write_wait, POLLOUT); |
| do_sleep++; |
| } |
| } |
| if (o_tty && o_tty->count <= 1) { |
| if (waitqueue_active(&o_tty->read_wait)) { |
| wake_up_poll(&o_tty->read_wait, POLLIN); |
| do_sleep++; |
| } |
| if (waitqueue_active(&o_tty->write_wait)) { |
| wake_up_poll(&o_tty->write_wait, POLLOUT); |
| do_sleep++; |
| } |
| } |
| if (!do_sleep) |
| break; |
| |
| if (once) { |
| once = 0; |
| tty_warn(tty, "read/write wait queue active!\n"); |
| } |
| schedule_timeout_killable(timeout); |
| if (timeout < 120 * HZ) |
| timeout = 2 * timeout + 1; |
| else |
| timeout = MAX_SCHEDULE_TIMEOUT; |
| } |
| |
| if (o_tty) { |
| if (--o_tty->count < 0) { |
| tty_warn(tty, "bad slave count (%d)\n", o_tty->count); |
| o_tty->count = 0; |
| } |
| } |
| if (--tty->count < 0) { |
| tty_warn(tty, "bad tty->count (%d)\n", tty->count); |
| tty->count = 0; |
| } |
| |
| /* |
| * We've decremented tty->count, so we need to remove this file |
| * descriptor off the tty->tty_files list; this serves two |
| * purposes: |
| * - check_tty_count sees the correct number of file descriptors |
| * associated with this tty. |
| * - do_tty_hangup no longer sees this file descriptor as |
| * something that needs to be handled for hangups. |
| */ |
| tty_del_file(filp); |
| |
| /* |
| * Perform some housekeeping before deciding whether to return. |
| * |
| * If _either_ side is closing, make sure there aren't any |
| * processes that still think tty or o_tty is their controlling |
| * tty. |
| */ |
| if (!tty->count) { |
| read_lock(&tasklist_lock); |
| session_clear_tty(tty->session); |
| if (o_tty) |
| session_clear_tty(o_tty->session); |
| read_unlock(&tasklist_lock); |
| } |
| |
| /* check whether both sides are closing ... */ |
| final = !tty->count && !(o_tty && o_tty->count); |
| |
| tty_unlock_slave(o_tty); |
| tty_unlock(tty); |
| |
| /* At this point, the tty->count == 0 should ensure a dead tty |
| cannot be re-opened by a racing opener */ |
| |
| if (!final) |
| return 0; |
| |
| tty_debug_hangup(tty, "final close\n"); |
| /* |
| * Ask the line discipline code to release its structures |
| */ |
| tty_ldisc_release(tty); |
| |
| /* Wait for pending work before tty destruction commmences */ |
| tty_flush_works(tty); |
| |
| tty_debug_hangup(tty, "freeing structure\n"); |
| /* |
| * The release_tty function takes care of the details of clearing |
| * the slots and preserving the termios structure. The tty_unlock_pair |
| * should be safe as we keep a kref while the tty is locked (so the |
| * unlock never unlocks a freed tty). |
| */ |
| mutex_lock(&tty_mutex); |
| release_tty(tty, idx); |
| mutex_unlock(&tty_mutex); |
| |
| return 0; |
| } |
| |
| /** |
| * tty_open_current_tty - get locked tty of current task |
| * @device: device number |
| * @filp: file pointer to tty |
| * @return: locked tty of the current task iff @device is /dev/tty |
| * |
| * Performs a re-open of the current task's controlling tty. |
| * |
| * We cannot return driver and index like for the other nodes because |
| * devpts will not work then. It expects inodes to be from devpts FS. |
| */ |
| static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp) |
| { |
| struct tty_struct *tty; |
| int retval; |
| |
| if (device != MKDEV(TTYAUX_MAJOR, 0)) |
| return NULL; |
| |
| tty = get_current_tty(); |
| if (!tty) |
| return ERR_PTR(-ENXIO); |
| |
| filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */ |
| /* noctty = 1; */ |
| tty_lock(tty); |
| tty_kref_put(tty); /* safe to drop the kref now */ |
| |
| retval = tty_reopen(tty); |
| if (retval < 0) { |
| tty_unlock(tty); |
| tty = ERR_PTR(retval); |
| } |
| return tty; |
| } |
| |
| /** |
| * tty_lookup_driver - lookup a tty driver for a given device file |
| * @device: device number |
| * @filp: file pointer to tty |
| * @noctty: set if the device should not become a controlling tty |
| * @index: index for the device in the @return driver |
| * @return: driver for this inode (with increased refcount) |
| * |
| * If @return is not erroneous, the caller is responsible to decrement the |
| * refcount by tty_driver_kref_put. |
| * |
| * Locking: tty_mutex protects get_tty_driver |
| */ |
| static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp, |
| int *index) |
| { |
| struct tty_driver *driver; |
| |
| switch (device) { |
| #ifdef CONFIG_VT |
| case MKDEV(TTY_MAJOR, 0): { |
| extern struct tty_driver *console_driver; |
| driver = tty_driver_kref_get(console_driver); |
| *index = fg_console; |
| break; |
| } |
| #endif |
| case MKDEV(TTYAUX_MAJOR, 1): { |
| struct tty_driver *console_driver = console_device(index); |
| if (console_driver) { |
| driver = tty_driver_kref_get(console_driver); |
| if (driver) { |
| /* Don't let /dev/console block */ |
| filp->f_flags |= O_NONBLOCK; |
| break; |
| } |
| } |
| return ERR_PTR(-ENODEV); |
| } |
| default: |
| driver = get_tty_driver(device, index); |
| if (!driver) |
| return ERR_PTR(-ENODEV); |
| break; |
| } |
| return driver; |
| } |
| |
| /** |
| * tty_open_by_driver - open a tty device |
| * @device: dev_t of device to open |
| * @inode: inode of device file |
| * @filp: file pointer to tty |
| * |
| * Performs the driver lookup, checks for a reopen, or otherwise |
| * performs the first-time tty initialization. |
| * |
| * Returns the locked initialized or re-opened &tty_struct |
| * |
| * Claims the global tty_mutex to serialize: |
| * - concurrent first-time tty initialization |
| * - concurrent tty driver removal w/ lookup |
| * - concurrent tty removal from driver table |
| */ |
| static struct tty_struct *tty_open_by_driver(dev_t device, struct inode *inode, |
| struct file *filp) |
| { |
| struct tty_struct *tty; |
| struct tty_driver *driver = NULL; |
| int index = -1; |
| int retval; |
| |
| mutex_lock(&tty_mutex); |
| driver = tty_lookup_driver(device, filp, &index); |
| if (IS_ERR(driver)) { |
| mutex_unlock(&tty_mutex); |
| return ERR_CAST(driver); |
| } |
| |
| /* check whether we're reopening an existing tty */ |
| tty = tty_driver_lookup_tty(driver, inode, index); |
| if (IS_ERR(tty)) { |
| mutex_unlock(&tty_mutex); |
| goto out; |
| } |
| |
| if (tty) { |
| mutex_unlock(&tty_mutex); |
| retval = tty_lock_interruptible(tty); |
| tty_kref_put(tty); /* drop kref from tty_driver_lookup_tty() */ |
| if (retval) { |
| if (retval == -EINTR) |
| retval = -ERESTARTSYS; |
| tty = ERR_PTR(retval); |
| goto out; |
| } |
| retval = tty_reopen(tty); |
| if (retval < 0) { |
| tty_unlock(tty); |
| tty = ERR_PTR(retval); |
| } |
| } else { /* Returns with the tty_lock held for now */ |
| tty = tty_init_dev(driver, index); |
| mutex_unlock(&tty_mutex); |
| } |
| out: |
| tty_driver_kref_put(driver); |
| return tty; |
| } |
| |
| /** |
| * tty_open - open a tty device |
| * @inode: inode of device file |
| * @filp: file pointer to tty |
| * |
| * tty_open and tty_release keep up the tty count that contains the |
| * number of opens done on a tty. We cannot use the inode-count, as |
| * different inodes might point to the same tty. |
| * |
| * Open-counting is needed for pty masters, as well as for keeping |
| * track of serial lines: DTR is dropped when the last close happens. |
| * (This is not done solely through tty->count, now. - Ted 1/27/92) |
| * |
| * The termios state of a pty is reset on first open so that |
| * settings don't persist across reuse. |
| * |
| * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev. |
| * tty->count should protect the rest. |
| * ->siglock protects ->signal/->sighand |
| * |
| * Note: the tty_unlock/lock cases without a ref are only safe due to |
| * tty_mutex |
| */ |
| |
| static int tty_open(struct inode *inode, struct file *filp) |
| { |
| struct tty_struct *tty; |
| int noctty, retval; |
| dev_t device = inode->i_rdev; |
| unsigned saved_flags = filp->f_flags; |
| |
| nonseekable_open(inode, filp); |
| |
| retry_open: |
| retval = tty_alloc_file(filp); |
| if (retval) |
| return -ENOMEM; |
| |
| tty = tty_open_current_tty(device, filp); |
| if (!tty) |
| tty = tty_open_by_driver(device, inode, filp); |
| |
| if (IS_ERR(tty)) { |
| tty_free_file(filp); |
| retval = PTR_ERR(tty); |
| if (retval != -EAGAIN || signal_pending(current)) |
| return retval; |
| schedule(); |
| goto retry_open; |
| } |
| |
| tty_add_file(tty, filp); |
| |
| check_tty_count(tty, __func__); |
| tty_debug_hangup(tty, "opening (count=%d)\n", tty->count); |
| |
| if (tty->ops->open) |
| retval = tty->ops->open(tty, filp); |
| else |
| retval = -ENODEV; |
| filp->f_flags = saved_flags; |
| |
| if (retval) { |
| tty_debug_hangup(tty, "open error %d, releasing\n", retval); |
| |
| tty_unlock(tty); /* need to call tty_release without BTM */ |
| tty_release(inode, filp); |
| if (retval != -ERESTARTSYS) |
| return retval; |
| |
| if (signal_pending(current)) |
| return retval; |
| |
| schedule(); |
| /* |
| * Need to reset f_op in case a hangup happened. |
| */ |
| if (tty_hung_up_p(filp)) |
| filp->f_op = &tty_fops; |
| goto retry_open; |
| } |
| clear_bit(TTY_HUPPED, &tty->flags); |
| |
| |
| read_lock(&tasklist_lock); |
| spin_lock_irq(¤t->sighand->siglock); |
| noctty = (filp->f_flags & O_NOCTTY) || |
| (IS_ENABLED(CONFIG_VT) && device == MKDEV(TTY_MAJOR, 0)) || |
| device == MKDEV(TTYAUX_MAJOR, 1) || |
| (tty->driver->type == TTY_DRIVER_TYPE_PTY && |
| tty->driver->subtype == PTY_TYPE_MASTER); |
| |
| if (!noctty && |
| current->signal->leader && |
| !current->signal->tty && |
| tty->session == NULL) { |
| /* |
| * Don't let a process that only has write access to the tty |
| * obtain the privileges associated with having a tty as |
| * controlling terminal (being able to reopen it with full |
| * access through /dev/tty, being able to perform pushback). |
| * Many distributions set the group of all ttys to "tty" and |
| * grant write-only access to all terminals for setgid tty |
| * binaries, which should not imply full privileges on all ttys. |
| * |
| * This could theoretically break old code that performs open() |
| * on a write-only file descriptor. In that case, it might be |
| * necessary to also permit this if |
| * inode_permission(inode, MAY_READ) == 0. |
| */ |
| if (filp->f_mode & FMODE_READ) |
| __proc_set_tty(tty); |
| } |
| spin_unlock_irq(¤t->sighand->siglock); |
| read_unlock(&tasklist_lock); |
| tty_unlock(tty); |
| return 0; |
| } |
| |
| |
| |
| /** |
| * tty_poll - check tty status |
| * @filp: file being polled |
| * @wait: poll wait structures to update |
| * |
| * Call the line discipline polling method to obtain the poll |
| * status of the device. |
| * |
| * Locking: locks called line discipline but ldisc poll method |
| * may be re-entered freely by other callers. |
| */ |
| |
| static unsigned int tty_poll(struct file *filp, poll_table *wait) |
| { |
| struct tty_struct *tty = file_tty(filp); |
| struct tty_ldisc *ld; |
| int ret = 0; |
| |
| if (tty_paranoia_check(tty, file_inode(filp), "tty_poll")) |
| return 0; |
| |
| ld = tty_ldisc_ref_wait(tty); |
| if (!ld) |
| return hung_up_tty_poll(filp, wait); |
| if (ld->ops->poll) |
| ret = ld->ops->poll(tty, filp, wait); |
| tty_ldisc_deref(ld); |
| return ret; |
| } |
| |
| static int __tty_fasync(int fd, struct file *filp, int on) |
| { |
| struct tty_struct *tty = file_tty(filp); |
| unsigned long flags; |
| int retval = 0; |
| |
| if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync")) |
| goto out; |
| |
| retval = fasync_helper(fd, filp, on, &tty->fasync); |
| if (retval <= 0) |
| goto out; |
| |
| if (on) { |
| enum pid_type type; |
| struct pid *pid; |
| |
| spin_lock_irqsave(&tty->ctrl_lock, flags); |
| if (tty->pgrp) { |
| pid = tty->pgrp; |
| type = PIDTYPE_PGID; |
| } else { |
| pid = task_pid(current); |
| type = PIDTYPE_PID; |
| } |
| get_pid(pid); |
| spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
| __f_setown(filp, pid, type, 0); |
| put_pid(pid); |
| retval = 0; |
| } |
| out: |
| return retval; |
| } |
| |
| static int tty_fasync(int fd, struct file *filp, int on) |
| { |
| struct tty_struct *tty = file_tty(filp); |
| int retval = -ENOTTY; |
| |
| tty_lock(tty); |
| if (!tty_hung_up_p(filp)) |
| retval = __tty_fasync(fd, filp, on); |
| tty_unlock(tty); |
| |
| return retval; |
| } |
| |
| /** |
| * tiocsti - fake input character |
| * @tty: tty to fake input into |
| * @p: pointer to character |
| * |
| * Fake input to a tty device. Does the necessary locking and |
| * input management. |
| * |
| * FIXME: does not honour flow control ?? |
| * |
| * Locking: |
| * Called functions take tty_ldiscs_lock |
| * current->signal->tty check is safe without locks |
| * |
| * FIXME: may race normal receive processing |
| */ |
| |
| static int tiocsti(struct tty_struct *tty, char __user *p) |
| { |
| char ch, mbz = 0; |
| struct tty_ldisc *ld; |
| |
| if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN)) |
| return -EPERM; |
| if (get_user(ch, p)) |
| return -EFAULT; |
| tty_audit_tiocsti(tty, ch); |
| ld = tty_ldisc_ref_wait(tty); |
| if (!ld) |
| return -EIO; |
| ld->ops->receive_buf(tty, &ch, &mbz, 1); |
| tty_ldisc_deref(ld); |
| return 0; |
| } |
| |
| /** |
| * tiocgwinsz - implement window query ioctl |
| * @tty; tty |
| * @arg: user buffer for result |
| * |
| * Copies the kernel idea of the window size into the user buffer. |
| * |
| * Locking: tty->winsize_mutex is taken to ensure the winsize data |
| * is consistent. |
| */ |
| |
| static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg) |
| { |
| int err; |
| |
| mutex_lock(&tty->winsize_mutex); |
| err = copy_to_user(arg, &tty->winsize, sizeof(*arg)); |
| mutex_unlock(&tty->winsize_mutex); |
| |
| return err ? -EFAULT: 0; |
| } |
| |
| /** |
| * tty_do_resize - resize event |
| * @tty: tty being resized |
| * @rows: rows (character) |
| * @cols: cols (character) |
| * |
| * Update the termios variables and send the necessary signals to |
| * peform a terminal resize correctly |
| */ |
| |
| int tty_do_resize(struct tty_struct *tty, struct winsize *ws) |
| { |
| struct pid *pgrp; |
| |
| /* Lock the tty */ |
| mutex_lock(&tty->winsize_mutex); |
| if (!memcmp(ws, &tty->winsize, sizeof(*ws))) |
| goto done; |
| |
| /* Signal the foreground process group */ |
| pgrp = tty_get_pgrp(tty); |
| if (pgrp) |
| kill_pgrp(pgrp, SIGWINCH, 1); |
| put_pid(pgrp); |
| |
| tty->winsize = *ws; |
| done: |
| mutex_unlock(&tty->winsize_mutex); |
| return 0; |
| } |
| EXPORT_SYMBOL(tty_do_resize); |
| |
| /** |
| * tiocswinsz - implement window size set ioctl |
| * @tty; tty side of tty |
| * @arg: user buffer for result |
| * |
| * Copies the user idea of the window size to the kernel. Traditionally |
| * this is just advisory information but for the Linux console it |
| * actually has driver level meaning and triggers a VC resize. |
| * |
| * Locking: |
| * Driver dependent. The default do_resize method takes the |
| * tty termios mutex and ctrl_lock. The console takes its own lock |
| * then calls into the default method. |
| */ |
| |
| static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg) |
| { |
| struct winsize tmp_ws; |
| if (copy_from_user(&tmp_ws, arg, sizeof(*arg))) |
| return -EFAULT; |
| |
| if (tty->ops->resize) |
| return tty->ops->resize(tty, &tmp_ws); |
| else |
| return tty_do_resize(tty, &tmp_ws); |
| } |
| |
| /** |
| * tioccons - allow admin to move logical console |
| * @file: the file to become console |
| * |
| * Allow the administrator to move the redirected console device |
| * |
| * Locking: uses redirect_lock to guard the redirect information |
| */ |
| |
| static int tioccons(struct file *file) |
| { |
| if (!capable(CAP_SYS_ADMIN)) |
| return -EPERM; |
| if (file->f_op->write == redirected_tty_write) { |
| struct file *f; |
| spin_lock(&redirect_lock); |
| f = redirect; |
| redirect = NULL; |
| spin_unlock(&redirect_lock); |
| if (f) |
| fput(f); |
| return 0; |
| } |
| spin_lock(&redirect_lock); |
| if (redirect) { |
| spin_unlock(&redirect_lock); |
| return -EBUSY; |
| } |
| redirect = get_file(file); |
| spin_unlock(&redirect_lock); |
| return 0; |
| } |
| |
| /** |
| * fionbio - non blocking ioctl |
| * @file: file to set blocking value |
| * @p: user parameter |
| * |
| * Historical tty interfaces had a blocking control ioctl before |
| * the generic functionality existed. This piece of history is preserved |
| * in the expected tty API of posix OS's. |
| * |
| * Locking: none, the open file handle ensures it won't go away. |
| */ |
| |
| static int fionbio(struct file *file, int __user *p) |
| { |
| int nonblock; |
| |
| if (get_user(nonblock, p)) |
| return -EFAULT; |
| |
| spin_lock(&file->f_lock); |
| if (nonblock) |
| file->f_flags |= O_NONBLOCK; |
| else |
| file->f_flags &= ~O_NONBLOCK; |
| spin_unlock(&file->f_lock); |
| return 0; |
| } |
| |
| /** |
| * 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_lock() to serialize proc_set_tty() for this tty |
| * Takes tasklist_lock internally to walk sessions |
| * Takes ->siglock() when updating signal->tty |
| */ |
| |
| static int tiocsctty(struct tty_struct *tty, struct file *file, int arg) |
| { |
| int ret = 0; |
| |
| tty_lock(tty); |
| read_lock(&tasklist_lock); |
| |
| if (current->signal->leader && (task_session(current) == tty->session)) |
| goto unlock; |
| |
| /* |
| * 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 |
| */ |
| session_clear_tty(tty->session); |
| } else { |
| ret = -EPERM; |
| goto unlock; |
| } |
| } |
| |
| /* See the comment in tty_open(). */ |
| if ((file->f_mode & FMODE_READ) == 0 && !capable(CAP_SYS_ADMIN)) { |
| ret = -EPERM; |
| goto unlock; |
| } |
| |
| proc_set_tty(tty); |
| unlock: |
| read_unlock(&tasklist_lock); |
| tty_unlock(tty); |
| 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); |
| |
| /* |
| * This checks not only the pgrp, but falls back on the pid if no |
| * satisfactory pgrp is found. I dunno - gdb doesn't work correctly |
| * without this... |
| * |
| * The caller must hold rcu lock or the tasklist lock. |
| */ |
| static struct pid *session_of_pgrp(struct pid *pgrp) |
| { |
| struct task_struct *p; |
| struct pid *sid = NULL; |
| |
| p = pid_task(pgrp, PIDTYPE_PGID); |
| if (p == NULL) |
| p = pid_task(pgrp, PIDTYPE_PID); |
| if (p != NULL) |
| sid = task_session(p); |
| |
| return sid; |
| } |
| |
| /** |
| * tiocgpgrp - get process group |
| * @tty: tty passed by user |
| * @real_tty: tty side of the tty passed 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); |
| |
| 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_irq(&tty->ctrl_lock); |
| put_pid(real_tty->pgrp); |
| real_tty->pgrp = get_pid(pgrp); |
| spin_unlock_irq(&tty->ctrl_lock); |
| out_unlock: |
| rcu_read_unlock(); |
| return retval; |
| } |
| |
| /** |
| * tiocgsid - get session id |
| * @tty: tty passed by user |
| * @real_tty: tty side of the tty passed 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 disc; |
| int ret; |
| |
| if (get_user(disc, p)) |
| return -EFAULT; |
| |
| ret = tty_set_ldisc(tty, disc); |
| |
| return ret; |
| } |
| |
| /** |
| * tiocgetd - get line discipline |
| * @tty: tty device |
| * @p: pointer to user data |
| * |
| * Retrieves the line discipline id directly from the ldisc. |
| * |
| * Locking: waits for ldisc reference (in case the line discipline |
| * is changing or the tty is being hungup) |
| */ |
| |
| static int tiocgetd(struct tty_struct *tty, int __user *p) |
| { |
| struct tty_ldisc *ld; |
| int ret; |
| |
| ld = tty_ldisc_ref_wait(tty); |
| if (!ld) |
| return -EIO; |
| ret = put_user(ld->ops->num, p); |
| tty_ldisc_deref(ld); |
| return ret; |
| } |
| |
| /** |
| * send_break - performed time break |
| * @tty: device to break on |
| * @duration: timeout in mS |
| * |
| * Perform a timed break on hardware that lacks its own driver level |
| * timed break functionality. |
| * |
| * Locking: |
| * atomic_write_lock serializes |
| * |
| */ |
| |
| static int send_break(struct tty_struct *tty, unsigned int duration) |
| { |
| int retval; |
| |
| if (tty->ops->break_ctl == NULL) |
| return 0; |
| |
| if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK) |
| retval = tty->ops->break_ctl(tty, duration); |
| else { |
| /* Do the work ourselves */ |
| if (tty_write_lock(tty, 0) < 0) |
| return -EINTR; |
| retval = tty->ops->break_ctl(tty, -1); |
| if (retval) |
| goto out; |
| if (!signal_pending(current)) |
| msleep_interruptible(duration); |
| retval = tty->ops->break_ctl(tty, 0); |
| out: |
| tty_write_unlock(tty); |
| if (signal_pending(current)) |
| retval = -EINTR; |
| } |
| return retval; |
| } |
| |
| /** |
| * tty_tiocmget - get modem status |
| * @tty: tty device |
| * @file: user file pointer |
| * @p: pointer to result |
| * |
| * Obtain the modem status bits from the tty driver if the feature |
| * is supported. Return -EINVAL if it is not available. |
| * |
| * Locking: none (up to the driver) |
| */ |
| |
| static int tty_tiocmget(struct tty_struct *tty, int __user *p) |
| { |
| int retval = -EINVAL; |
| |
| if (tty->ops->tiocmget) { |
| retval = tty->ops->tiocmget(tty); |
| |
| if (retval >= 0) |
| retval = put_user(retval, p); |
| } |
| return retval; |
| } |
| |
| /** |
| * tty_tiocmset - set modem status |
| * @tty: tty device |
| * @cmd: command - clear bits, set bits or set all |
| * @p: pointer to desired bits |
| * |
| * Set the modem status bits from the tty driver if the feature |
| * is supported. Return -EINVAL if it is not available. |
| * |
| * Locking: none (up to the driver) |
| */ |
| |
| static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd, |
| unsigned __user *p) |
| { |
| int retval; |
| unsigned int set, clear, val; |
| |
| if (tty->ops->tiocmset == NULL) |
| return -EINVAL; |
| |
| retval = get_user(val, p); |
| if (retval) |
| return retval; |
| set = clear = 0; |
| switch (cmd) { |
| case TIOCMBIS: |
| set = val; |
| break; |
| case TIOCMBIC: |
| clear = val; |
| break; |
| case TIOCMSET: |
| set = val; |
| clear = ~val; |
| break; |
| } |
| set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP; |
| clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP; |
| return tty->ops->tiocmset(tty, set, clear); |
| } |
| |
| static int tty_tiocgicount(struct tty_struct *tty, void __user *arg) |
| { |
| int retval = -EINVAL; |
| struct serial_icounter_struct icount; |
| memset(&icount, 0, sizeof(icount)); |
| if (tty->ops->get_icount) |
| retval = tty->ops->get_icount(tty, &icount); |
| if (retval != 0) |
| return retval; |
| if (copy_to_user(arg, &icount, sizeof(icount))) |
| return -EFAULT; |
| return 0; |
| } |
| |
| static void tty_warn_deprecated_flags(struct serial_struct __user *ss) |
| { |
| static DEFINE_RATELIMIT_STATE(depr_flags, |
| DEFAULT_RATELIMIT_INTERVAL, |
| DEFAULT_RATELIMIT_BURST); |
| char comm[TASK_COMM_LEN]; |
| int flags; |
| |
| if (get_user(flags, &ss->flags)) |
| return; |
| |
| flags &= ASYNC_DEPRECATED; |
| |
| if (flags && __ratelimit(&depr_flags)) |
| pr_warning("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n", |
| __func__, get_task_comm(comm, current), flags); |
| } |
| |
| /* |
| * if pty, return the slave side (real_tty) |
| * otherwise, return self |
| */ |
| static struct tty_struct *tty_pair_get_tty(struct tty_struct *tty) |
| { |
| if (tty->driver->type == TTY_DRIVER_TYPE_PTY && |
| tty->driver->subtype == PTY_TYPE_MASTER) |
| tty = tty->link; |
| return tty; |
| } |
| |
| /* |
| * Split this up, as gcc can choke on it otherwise.. |
| */ |
| long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
| { |
| struct tty_struct *tty = file_tty(file); |
| struct tty_struct *real_tty; |
| void __user *p = (void __user *)arg; |
| int retval; |
| struct tty_ldisc *ld; |
| |
| if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl")) |
| return -EINVAL; |
| |
| real_tty = tty_pair_get_tty(tty); |
| |
| /* |
| * Factor out some common prep work |
| */ |
| switch (cmd) { |
| case TIOCSETD: |
| case TIOCSBRK: |
| case TIOCCBRK: |
| case TCSBRK: |
| case TCSBRKP: |
| retval = tty_check_change(tty); |
| if (retval) |
| return retval; |
| if (cmd != TIOCCBRK) { |
| tty_wait_until_sent(tty, 0); |
| if (signal_pending(current)) |
| return -EINTR; |
| } |
| break; |
| } |
| |
| /* |
| * Now do the stuff. |
| */ |
| switch (cmd) { |
| case TIOCSTI: |
| return tiocsti(tty, p); |
| case TIOCGWINSZ: |
| return tiocgwinsz(real_tty, p); |
| case TIOCSWINSZ: |
| return tiocswinsz(real_tty, p); |
| case TIOCCONS: |
| return real_tty != tty ? -EINVAL : tioccons(file); |
| case FIONBIO: |
| return fionbio(file, p); |
| case TIOCEXCL: |
| set_bit(TTY_EXCLUSIVE, &tty->flags); |
| return 0; |
| case TIOCNXCL: |
| clear_bit(TTY_EXCLUSIVE, &tty->flags); |
| return 0; |
| case TIOCGEXCL: |
| { |
| int excl = test_bit(TTY_EXCLUSIVE, &tty->flags); |
| return put_user(excl, (int __user *)p); |
| } |
| case TIOCNOTTY: |
| if (current->signal->tty != tty) |
| return -ENOTTY; |
| no_tty(); |
| return 0; |
| case TIOCSCTTY: |
| return tiocsctty(real_tty, file, 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 tiocgetd(tty, p); |
| case TIOCSETD: |
| return tiocsetd(tty, p); |
| case TIOCVHANGUP: |
| if (!capable(CAP_SYS_ADMIN)) |
| return -EPERM; |
| tty_vhangup(tty); |
| return 0; |
| case TIOCGDEV: |
| { |
| unsigned int ret = new_encode_dev(tty_devnum(real_tty)); |
| return put_user(ret, (unsigned int __user *)p); |
| } |
| /* |
| * Break handling |
| */ |
| case TIOCSBRK: /* Turn break on, unconditionally */ |
| if (tty->ops->break_ctl) |
| return tty->ops->break_ctl(tty, -1); |
| return 0; |
| case TIOCCBRK: /* Turn break off, unconditionally */ |
| if (tty->ops->break_ctl) |
| return tty->ops->break_ctl(tty, 0); |
| return 0; |
| case TCSBRK: /* SVID version: non-zero arg --> no break */ |
| /* non-zero arg means wait for all output data |
| * to be sent (performed above) but don't send break. |
| * This is used by the tcdrain() termios function. |
| */ |
| if (!arg) |
| return send_break(tty, 250); |
| return 0; |
| case TCSBRKP: /* support for POSIX tcsendbreak() */ |
| return send_break(tty, arg ? arg*100 : 250); |
| |
| case TIOCMGET: |
| return tty_tiocmget(tty, p); |
| case TIOCMSET: |
| case TIOCMBIC: |
| case TIOCMBIS: |
| return tty_tiocmset(tty, cmd, p); |
| case TIOCGICOUNT: |
| retval = tty_tiocgicount(tty, p); |
| /* For the moment allow fall through to the old method */ |
| if (retval != -EINVAL) |
| return retval; |
| break; |
| case TCFLSH: |
| switch (arg) { |
| case TCIFLUSH: |
| case TCIOFLUSH: |
| /* flush tty buffer and allow ldisc to process ioctl */ |
| tty_buffer_flush(tty, NULL); |
| break; |
| } |
| break; |
| case TIOCSSERIAL: |
| tty_warn_deprecated_flags(p); |
| break; |
| } |
| if (tty->ops->ioctl) { |
| retval = tty->ops->ioctl(tty, cmd, arg); |
| if (retval != -ENOIOCTLCMD) |
| return retval; |
| } |
| ld = tty_ldisc_ref_wait(tty); |
| if (!ld) |
| return hung_up_tty_ioctl(file, cmd, arg); |
| retval = -EINVAL; |
| if (ld->ops->ioctl) { |
| retval = ld->ops->ioctl(tty, file, cmd, arg); |
| if (retval == -ENOIOCTLCMD) |
| retval = -ENOTTY; |
| } |
| tty_ldisc_deref(ld); |
| return retval; |
| } |
| |
| #ifdef CONFIG_COMPAT |
| static long tty_compat_ioctl(struct file *file, unsigned int cmd, |
| unsigned long arg) |
| { |
| struct tty_struct *tty = file_tty(file); |
| struct tty_ldisc *ld; |
| int retval = -ENOIOCTLCMD; |
| |
| if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl")) |
| return -EINVAL; |
| |
| if (tty->ops->compat_ioctl) { |
| retval = tty->ops->compat_ioctl(tty, cmd, arg); |
| if (retval != -ENOIOCTLCMD) |
| return retval; |
| } |
| |
| ld = tty_ldisc_ref_wait(tty); |
| if (!ld) |
| return hung_up_tty_compat_ioctl(file, cmd, arg); |
| if (ld->ops->compat_ioctl) |
| retval = ld->ops->compat_ioctl(tty, file, cmd, arg); |
| else |
| retval = n_tty_compat_ioctl_helper(tty, file, cmd, arg); |
| tty_ldisc_deref(ld); |
| |
| return retval; |
| } |
| #endif |
| |
| static int this_tty(const void *t, struct file *file, unsigned fd) |
| { |
| if (likely(file->f_op->read != tty_read)) |
| return 0; |
| return file_tty(file) != t ? 0 : fd + 1; |
| } |
| |
| /* |
| * This implements the "Secure Attention Key" --- the idea is to |
| * prevent trojan horses by killing all processes associated with this |
| * tty when the user hits the "Secure Attention Key". Required for |
| * super-paranoid applications --- see the Orange Book for more details. |
| * |
| * This code could be nicer; ideally it should send a HUP, wait a few |
| * seconds, then send a INT, and then a KILL signal. But you then |
| * have to coordinate with the init process, since all processes associated |
| * with the current tty must be dead before the new getty is allowed |
| * to spawn. |
| * |
| * Now, if it would be correct ;-/ The current code has a nasty hole - |
| * it doesn't catch files in flight. We may send the descriptor to ourselves |
| * via AF_UNIX socket, close it and later fetch from socket. FIXME. |
| * |
| * Nasty bug: do_SAK is being called in interrupt context. This can |
| * deadlock. We punt it up to process context. AKPM - 16Mar2001 |
| */ |
| void __do_SAK(struct tty_struct *tty) |
| { |
| #ifdef TTY_SOFT_SAK |
| tty_hangup(tty); |
| #else |
| struct task_struct *g, *p; |
| struct pid *session; |
| int i; |
| |
| if (!tty) |
| return; |
| session = tty->session; |
| |
| tty_ldisc_flush(tty); |
| |
| tty_driver_flush_buffer(tty); |
| |
| read_lock(&tasklist_lock); |
| /* Kill the entire session */ |
| do_each_pid_task(session, PIDTYPE_SID, p) { |
| tty_notice(tty, "SAK: killed process %d (%s): by session\n", |
| task_pid_nr(p), p->comm); |
| send_sig(SIGKILL, p, 1); |
| } while_each_pid_task(session, PIDTYPE_SID, p); |
| |
| /* Now kill any processes that happen to have the tty open */ |
| do_each_thread(g, p) { |
| if (p->signal->tty == tty) { |
| tty_notice(tty, "SAK: killed process %d (%s): by controlling tty\n", |
| task_pid_nr(p), p->comm); |
| send_sig(SIGKILL, p, 1); |
| continue; |
| } |
| task_lock(p); |
| i = iterate_fd(p->files, 0, this_tty, tty); |
| if (i != 0) { |
| tty_notice(tty, "SAK: killed process %d (%s): by fd#%d\n", |
| task_pid_nr(p), p->comm, i - 1); |
| force_sig(SIGKILL, p); |
| } |
| task_unlock(p); |
| } while_each_thread(g, p); |
| read_unlock(&tasklist_lock); |
| #endif |
| } |
| |
| static void do_SAK_work(struct work_struct *work) |
| { |
| struct tty_struct *tty = |
| container_of(work, struct tty_struct, SAK_work); |
| __do_SAK(tty); |
| } |
| |
| /* |
| * The tq handling here is a little racy - tty->SAK_work may already be queued. |
| * Fortunately we don't need to worry, because if ->SAK_work is already queued, |
| * the values which we write to it will be identical to the values which it |
| * already has. --akpm |
| */ |
| void do_SAK(struct tty_struct *tty) |
| { |
| if (!tty) |
| return; |
| schedule_work(&tty->SAK_work); |
| } |
| |
| EXPORT_SYMBOL(do_SAK); |
| |
| static int dev_match_devt(struct device *dev, const void *data) |
| { |
| const dev_t *devt = data; |
| return dev->devt == *devt; |
| } |
| |
| /* Must put_device() after it's unused! */ |
| static struct device *tty_get_device(struct tty_struct *tty) |
| { |
| dev_t devt = tty_devnum(tty); |
| return class_find_device(tty_class, NULL, &devt, dev_match_devt); |
| } |
| |
| |
| /** |
| * alloc_tty_struct |
| * |
| * This subroutine allocates and initializes a tty structure. |
| * |
| * Locking: none - tty in question is not exposed at this point |
| */ |
| |
| struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx) |
| { |
| struct tty_struct *tty; |
| |
| tty = kzalloc(sizeof(*tty), GFP_KERNEL); |
| if (!tty) |
| return NULL; |
| |
| kref_init(&tty->kref); |
| tty->magic = TTY_MAGIC; |
| tty_ldisc_init(tty); |
| tty->session = NULL; |
| tty->pgrp = NULL; |
| mutex_init(&tty->legacy_mutex); |
| mutex_init(&tty->throttle_mutex); |
| init_rwsem(&tty->termios_rwsem); |
| mutex_init(&tty->winsize_mutex); |
| init_ldsem(&tty->ldisc_sem); |
| init_waitqueue_head(&tty->write_wait); |
| init_waitqueue_head(&tty->read_wait); |
| INIT_WORK(&tty->hangup_work, do_tty_hangup); |
| mutex_init(&tty->atomic_write_lock); |
| spin_lock_init(&tty->ctrl_lock); |
| spin_lock_init(&tty->flow_lock); |
| spin_lock_init(&tty->files_lock); |
| INIT_LIST_HEAD(&tty->tty_files); |
| INIT_WORK(&tty->SAK_work, do_SAK_work); |
| |
| tty->driver = driver; |
| tty->ops = driver->ops; |
| tty->index = idx; |
| tty_line_name(driver, idx, tty->name); |
| tty->dev = tty_get_device(tty); |
| |
| return tty; |
| } |
| |
| /** |
| * tty_put_char - write one character to a tty |
| * @tty: tty |
| * @ch: character |
| * |
| * Write one byte to the tty using the provided put_char method |
| * if present. Returns the number of characters successfully output. |
| * |
| * Note: the specific put_char operation in the driver layer may go |
| * away soon. Don't call it directly, use this method |
| */ |
| |
| int tty_put_char(struct tty_struct *tty, unsigned char ch) |
| { |
| if (tty->ops->put_char) |
| return tty->ops->put_char(tty, ch); |
| return tty->ops->write(tty, &ch, 1); |
| } |
| EXPORT_SYMBOL_GPL(tty_put_char); |
| |
| struct class *tty_class; |
| |
| static int tty_cdev_add(struct tty_driver *driver, dev_t dev, |
| unsigned int index, unsigned int count) |
| { |
| int err; |
| |
| /* init here, since reused cdevs cause crashes */ |
| driver->cdevs[index] = cdev_alloc(); |
| if (!driver->cdevs[index]) |
| return -ENOMEM; |
| driver->cdevs[index]->ops = &tty_fops; |
| driver->cdevs[index]->owner = driver->owner; |
| err = cdev_add(driver->cdevs[index], dev, count); |
| if (err) |
| kobject_put(&driver->cdevs[index]->kobj); |
| return err; |
| } |
| |
| /** |
| * tty_register_device - register a tty device |
| * @driver: the tty driver that describes the tty device |
| * @index: the index in the tty driver for this tty device |
| * @device: a struct device that is associated with this tty device. |
| * This field is optional, if there is no known struct device |
| * for this tty device it can be set to NULL safely. |
| * |
| * Returns a pointer to the struct device for this tty device |
| * (or ERR_PTR(-EFOO) on error). |
| * |
| * This call is required to be made to register an individual tty device |
| * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If |
| * that bit is not set, this function should not be called by a tty |
| * driver. |
| * |
| * Locking: ?? |
| */ |
| |
| struct device *tty_register_device(struct tty_driver *driver, unsigned index, |
| struct device *device) |
| { |
| return tty_register_device_attr(driver, index, device, NULL, NULL); |
| } |
| EXPORT_SYMBOL(tty_register_device); |
| |
| static void tty_device_create_release(struct device *dev) |
| { |
| dev_dbg(dev, "releasing...\n"); |
| kfree(dev); |
| } |
| |
| /** |
| * tty_register_device_attr - register a tty device |
| * @driver: the tty driver that describes the tty device |
| * @index: the index in the tty driver for this tty device |
| * @device: a struct device that is associated with this tty device. |
| * This field is optional, if there is no known struct device |
| * for this tty device it can be set to NULL safely. |
| * @drvdata: Driver data to be set to device. |
| * @attr_grp: Attribute group to be set on device. |
| * |
| * Returns a pointer to the struct device for this tty device |
| * (or ERR_PTR(-EFOO) on error). |
| * |
| * This call is required to be made to register an individual tty device |
| * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If |
| * that bit is not set, this function should not be called by a tty |
| * driver. |
| * |
| * Locking: ?? |
| */ |
| struct device *tty_register_device_attr(struct tty_driver *driver, |
| unsigned index, struct device *device, |
| void *drvdata, |
| const struct attribute_group **attr_grp) |
| { |
| char name[64]; |
| dev_t devt = MKDEV(driver->major, driver->minor_start) + index; |
| struct device *dev = NULL; |
| int retval = -ENODEV; |
| bool cdev = false; |
| |
| if (index >= driver->num) { |
| pr_err("%s: Attempt to register invalid tty line number (%d)\n", |
| driver->name, index); |
| return ERR_PTR(-EINVAL); |
| } |
| |
| if (driver->type == TTY_DRIVER_TYPE_PTY) |
| pty_line_name(driver, index, name); |
| else |
| tty_line_name(driver, index, name); |
| |
| if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) { |
| retval = tty_cdev_add(driver, devt, index, 1); |
| if (retval) |
| goto error; |
| cdev = true; |
| } |
| |
| dev = kzalloc(sizeof(*dev), GFP_KERNEL); |
| if (!dev) { |
| retval = -ENOMEM; |
| goto error; |
| } |
| |
| dev->devt = devt; |
| dev->class = tty_class; |
| dev->parent = device; |
| dev->release = tty_device_create_release; |
| dev_set_name(dev, "%s", name); |
| dev->groups = attr_grp; |
| dev_set_drvdata(dev, drvdata); |
| |
| retval = device_register(dev); |
| if (retval) |
| goto error; |
| |
| return dev; |
| |
| error: |
| put_device(dev); |
| if (cdev) { |
| cdev_del(driver->cdevs[index]); |
| driver->cdevs[index] = NULL; |
| } |
| return ERR_PTR(retval); |
| } |
| EXPORT_SYMBOL_GPL(tty_register_device_attr); |
| |
| /** |
| * tty_unregister_device - unregister a tty device |
| * @driver: the tty driver that describes the tty device |
| * @index: the index in the tty driver for this tty device |
| * |
| * If a tty device is registered with a call to tty_register_device() then |
| * this function must be called when the tty device is gone. |
| * |
| * Locking: ?? |
| */ |
| |
| void tty_unregister_device(struct tty_driver *driver, unsigned index) |
| { |
| device_destroy(tty_class, |
| MKDEV(driver->major, driver->minor_start) + index); |
| if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) { |
| cdev_del(driver->cdevs[index]); |
| driver->cdevs[index] = NULL; |
| } |
| } |
| EXPORT_SYMBOL(tty_unregister_device); |
| |
| /** |
| * __tty_alloc_driver -- allocate tty driver |
| * @lines: count of lines this driver can handle at most |
| * @owner: module which is repsonsible for this driver |
| * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags |
| * |
| * This should not be called directly, some of the provided macros should be |
| * used instead. Use IS_ERR and friends on @retval. |
| */ |
| struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner, |
| unsigned long flags) |
| { |
| struct tty_driver *driver; |
| unsigned int cdevs = 1; |
| int err; |
| |
| if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1)) |
| return ERR_PTR(-EINVAL); |
| |
| driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL); |
| if (!driver) |
| return ERR_PTR(-ENOMEM); |
| |
| kref_init(&driver->kref); |
| driver->magic = TTY_DRIVER_MAGIC; |
| driver->num = lines; |
| driver->owner = owner; |
| driver->flags = flags; |
| |
| if (!(flags & TTY_DRIVER_DEVPTS_MEM)) { |
| driver->ttys = kcalloc(lines, sizeof(*driver->ttys), |
| GFP_KERNEL); |
| driver->termios = kcalloc(lines, sizeof(*driver->termios), |
| GFP_KERNEL); |
| if (!driver->ttys || !driver->termios) { |
| err = -ENOMEM; |
| goto err_free_all; |
| } |
| } |
| |
| if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) { |
| driver->ports = kcalloc(lines, sizeof(*driver->ports), |
| GFP_KERNEL); |
| if (!driver->ports) { |
| err = -ENOMEM; |
| goto err_free_all; |
| } |
| cdevs = lines; |
| } |
| |
| driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL); |
| if (!driver->cdevs) { |
| err = -ENOMEM; |
| goto err_free_all; |
| } |
| |
| return driver; |
| err_free_all: |
| kfree(driver->ports); |
| kfree(driver->ttys); |
| kfree(driver->termios); |
| kfree(driver->cdevs); |
| kfree(driver); |
| return ERR_PTR(err); |
| } |
| EXPORT_SYMBOL(__tty_alloc_driver); |
| |
| static void destruct_tty_driver(struct kref *kref) |
| { |
| struct tty_driver *driver = container_of(kref, struct tty_driver, kref); |
| int i; |
| struct ktermios *tp; |
| |
| if (driver->flags & TTY_DRIVER_INSTALLED) { |
| /* |
| * 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); |
| } |
| proc_tty_unregister_driver(driver); |
| if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) |
| cdev_del(driver->cdevs[0]); |
| } |
| kfree(driver->cdevs); |
| kfree(driver->ports); |
| kfree(driver->termios); |
| kfree(driver->ttys); |
| kfree(driver); |
| } |
| |
| void tty_driver_kref_put(struct tty_driver *driver) |
| { |
| kref_put(&driver->kref, destruct_tty_driver); |
| } |
| EXPORT_SYMBOL(tty_driver_kref_put); |
| |
| void tty_set_operations(struct tty_driver *driver, |
| const struct tty_operations *op) |
| { |
| driver->ops = op; |
| }; |
| EXPORT_SYMBOL(tty_set_operations); |
| |
| void put_tty_driver(struct tty_driver *d) |
| { |
| tty_driver_kref_put(d); |
| } |
| EXPORT_SYMBOL(put_tty_driver); |
| |
| /* |
| * Called by a tty driver to register itself. |
| */ |
| int tty_register_driver(struct tty_driver *driver) |
| { |
| int error; |
| int i; |
| dev_t dev; |
| struct device *d; |
| |
| if (!driver->major) { |
| error = alloc_chrdev_region(&dev, driver->minor_start, |
| driver->num, driver->name); |
| if (!error) { |
| driver->major = MAJOR(dev); |
| driver->minor_start = MINOR(dev); |
| } |
| } else { |
| dev = MKDEV(driver->major, driver->minor_start); |
| error = register_chrdev_region(dev, driver->num, driver->name); |
| } |
| if (error < 0) |
| goto err; |
| |
| if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) { |
| error = tty_cdev_add(driver, dev, 0, driver->num); |
| if (error) |
| goto err_unreg_char; |
| } |
| |
| mutex_lock(&tty_mutex); |
| list_add(&driver->tty_drivers, &tty_drivers); |
| mutex_unlock(&tty_mutex); |
| |
| if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) { |
| for (i = 0; i < driver->num; i++) { |
| d = tty_register_device(driver, i, NULL); |
| if (IS_ERR(d)) { |
| error = PTR_ERR(d); |
| goto err_unreg_devs; |
| } |
| } |
| } |
| proc_tty_register_driver(driver); |
| driver->flags |= TTY_DRIVER_INSTALLED; |
| return 0; |
| |
| err_unreg_devs: |
| for (i--; i >= 0; i--) |
| tty_unregister_device(driver, i); |
| |
| mutex_lock(&tty_mutex); |
| list_del(&driver->tty_drivers); |
| mutex_unlock(&tty_mutex); |
| |
| err_unreg_char: |
| unregister_chrdev_region(dev, driver->num); |
| err: |
| return error; |
| } |
| EXPORT_SYMBOL(tty_register_driver); |
| |
| /* |
| * Called by a tty driver to unregister itself. |
| */ |
| int tty_unregister_driver(struct tty_driver *driver) |
| { |
| #if 0 |
| /* FIXME */ |
| if (driver->refcount) |
| return -EBUSY; |
| #endif |
| unregister_chrdev_region(MKDEV(driver->major, driver->minor_start), |
| driver->num); |
| mutex_lock(&tty_mutex); |
| list_del(&driver->tty_drivers); |
| mutex_unlock(&tty_mutex); |
| return 0; |
| } |
| |
| EXPORT_SYMBOL(tty_unregister_driver); |
| |
| dev_t tty_devnum(struct tty_struct *tty) |
| { |
| return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index; |
| } |
| EXPORT_SYMBOL(tty_devnum); |
| |
| void tty_default_fops(struct file_operations *fops) |
| { |
| *fops = tty_fops; |
| } |
| |
| /* |
| * 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. */ |
| n_tty_init(); |
| |
| /* |
| * 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 char *tty_devnode(struct device *dev, umode_t *mode) |
| { |
| if (!mode) |
| return NULL; |
| if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) || |
| dev->devt == MKDEV(TTYAUX_MAJOR, 2)) |
| *mode = 0666; |
| return NULL; |
| } |
| |
| static int __init tty_class_init(void) |
| { |
| tty_class = class_create(THIS_MODULE, "tty"); |
| if (IS_ERR(tty_class)) |
| return PTR_ERR(tty_class); |
| tty_class->devnode = tty_devnode; |
| return 0; |
| } |
| |
| postcore_initcall(tty_class_init); |
| |
| /* 3/2004 jmc: why do these devices exist? */ |
| static struct cdev tty_cdev, console_cdev; |
| |
| static ssize_t show_cons_active(struct device *dev, |
| struct device_attribute *attr, char *buf) |
| { |
| struct console *cs[16]; |
| int i = 0; |
| struct console *c; |
| ssize_t count = 0; |
| |
| console_lock(); |
| for_each_console(c) { |
| if (!c->device) |
| continue; |
| if (!c->write) |
| continue; |
| if ((c->flags & CON_ENABLED) == 0) |
| continue; |
| cs[i++] = c; |
| if (i >= ARRAY_SIZE(cs)) |
| break; |
| } |
| while (i--) { |
| int index = cs[i]->index; |
| struct tty_driver *drv = cs[i]->device(cs[i], &index); |
| |
| /* don't resolve tty0 as some programs depend on it */ |
| if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR)) |
| count += tty_line_name(drv, index, buf + count); |
| else |
| count += sprintf(buf + count, "%s%d", |
| cs[i]->name, cs[i]->index); |
| |
| count += sprintf(buf + count, "%c", i ? ' ':'\n'); |
| } |
| console_unlock(); |
| |
| return count; |
| } |
| static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL); |
| |
| static struct attribute *cons_dev_attrs[] = { |
| &dev_attr_active.attr, |
| NULL |
| }; |
| |
| ATTRIBUTE_GROUPS(cons_dev); |
| |
| static struct device *consdev; |
| |
| void console_sysfs_notify(void) |
| { |
| if (consdev) |
| sysfs_notify(&consdev->kobj, NULL, "active"); |
| } |
| |
| /* |
| * Ok, now we can initialize the rest of the tty devices and can count |
| * on memory allocations, interrupts etc.. |
| */ |
| int __init tty_init(void) |
| { |
| cdev_init(&tty_cdev, &tty_fops); |
| if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) || |
| register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0) |
| panic("Couldn't register /dev/tty driver\n"); |
| device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty"); |
| |
| cdev_init(&console_cdev, &console_fops); |
| if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) || |
| register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0) |
| panic("Couldn't register /dev/console driver\n"); |
| consdev = device_create_with_groups(tty_class, NULL, |
| MKDEV(TTYAUX_MAJOR, 1), NULL, |
| cons_dev_groups, "console"); |
| if (IS_ERR(consdev)) |
| consdev = NULL; |
| |
| #ifdef CONFIG_VT |
| vty_init(&console_fops); |
| #endif |
| return 0; |
| } |
| |