/* * linux/drivers/char/tty_io.c * * Copyright (C) 1991, 1992 Linus Torvalds */ /* * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles * or rs-channels. It also implements echoing, cooked mode etc. * * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0. * * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the * tty_struct and tty_queue structures. Previously there was an array * of 256 tty_struct's which was statically allocated, and the * tty_queue structures were allocated at boot time. Both are now * dynamically allocated only when the tty is open. * * Also restructured routines so that there is more of a separation * between the high-level tty routines (tty_io.c and tty_ioctl.c) and * the low-level tty routines (serial.c, pty.c, console.c). This * makes for cleaner and more compact code. -TYT, 9/17/92 * * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines * which can be dynamically activated and de-activated by the line * discipline handling modules (like SLIP). * * NOTE: pay no attention to the line discipline code (yet); its * interface is still subject to change in this version... * -- TYT, 1/31/92 * * Added functionality to the OPOST tty handling. No delays, but all * other bits should be there. * -- Nick Holloway , 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 , March 97 * * Rewrote init_dev and release_dev to eliminate races. * -- Bill Hawes , June 97 * * Added devfs support. * -- C. Scott Ananian , 13-Jan-1998 * * Added support for a Unix98-style ptmx device. * -- C. Scott Ananian , 14-Jan-1998 * * Reduced memory usage for older ARM systems * -- Russell King * * Move do_SAK() into process context. Less stack use in devfs functions. * alloc_tty_struct() always uses kmalloc() * -- Andrew Morton 17Mar01 */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #undef TTY_DEBUG_HANGUP #define TTY_PARANOIA_CHECK 1 #define CHECK_TTY_COUNT 1 struct ktermios tty_std_termios = { /* for the benefit of tty drivers */ .c_iflag = ICRNL | IXON, .c_oflag = OPOST | ONLCR, .c_cflag = B38400 | CS8 | CREAD | HUPCL, .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOKE | IEXTEN, .c_cc = INIT_C_CC, .c_ispeed = 38400, .c_ospeed = 38400 }; EXPORT_SYMBOL(tty_std_termios); /* This list gets poked at by procfs and various bits of boot up code. This could do with some rationalisation such as pulling the tty proc function into this file */ LIST_HEAD(tty_drivers); /* linked list of tty drivers */ /* Mutex to protect creating and releasing a tty. This is shared with vt.c for deeply disgusting hack reasons */ DEFINE_MUTEX(tty_mutex); EXPORT_SYMBOL(tty_mutex); #ifdef CONFIG_UNIX98_PTYS extern struct tty_driver *ptm_driver; /* Unix98 pty masters; for /dev/ptmx */ static int ptmx_open(struct inode *, struct file *); #endif static void initialize_tty_struct(struct tty_struct *tty); static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *); static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *); ssize_t redirected_tty_write(struct file *, const char __user *, size_t, loff_t *); static unsigned int tty_poll(struct file *, poll_table *); static int tty_open(struct inode *, struct file *); static int tty_release(struct inode *, struct file *); long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg); #ifdef CONFIG_COMPAT static long tty_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg); #else #define tty_compat_ioctl NULL #endif static int tty_fasync(int fd, struct file *filp, int on); static void release_tty(struct tty_struct *tty, int idx); static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty); static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty); /** * alloc_tty_struct - allocate a tty object * * Return a new empty tty structure. The data fields have not * been initialized in any way but has been zeroed * * Locking: none */ static struct tty_struct *alloc_tty_struct(void) { return kzalloc(sizeof(struct tty_struct), GFP_KERNEL); } /** * free_tty_struct - free a disused tty * @tty: tty struct to free * * Free the write buffers, tty queue and tty memory itself. * * Locking: none. Must be called after tty is definitely unused */ static inline void free_tty_struct(struct tty_struct *tty) { kfree(tty->write_buf); tty_buffer_free_all(tty); kfree(tty); } #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base) /** * tty_name - return tty naming * @tty: tty structure * @buf: buffer for output * * Convert a tty structure into a name. The name reflects the kernel * naming policy and if udev is in use may not reflect user space * * Locking: none */ char *tty_name(struct tty_struct *tty, char *buf) { if (!tty) /* Hmm. NULL pointer. That's fun. */ strcpy(buf, "NULL tty"); else strcpy(buf, tty->name); return buf; } EXPORT_SYMBOL(tty_name); int tty_paranoia_check(struct tty_struct *tty, struct inode *inode, const char *routine) { #ifdef TTY_PARANOIA_CHECK if (!tty) { printk(KERN_WARNING "null TTY for (%d:%d) in %s\n", imajor(inode), iminor(inode), routine); return 1; } if (tty->magic != TTY_MAGIC) { printk(KERN_WARNING "bad magic number for tty struct (%d:%d) in %s\n", imajor(inode), iminor(inode), routine); return 1; } #endif return 0; } static int check_tty_count(struct tty_struct *tty, const char *routine) { #ifdef CHECK_TTY_COUNT struct list_head *p; int count = 0; file_list_lock(); list_for_each(p, &tty->tty_files) { count++; } file_list_unlock(); if (tty->driver->type == TTY_DRIVER_TYPE_PTY && tty->driver->subtype == PTY_TYPE_SLAVE && tty->link && tty->link->count) count++; if (tty->count != count) { printk(KERN_WARNING "Warning: dev (%s) tty->count(%d) " "!= #fd's(%d) in %s\n", tty->name, tty->count, count, routine); return count; } #endif return 0; } /** * get_tty_driver - find device of a tty * @dev_t: device identifier * @index: returns the index of the tty * * This routine returns a tty driver structure, given a device number * and also passes back the index number. * * Locking: caller must hold tty_mutex */ static struct tty_driver *get_tty_driver(dev_t device, int *index) { struct tty_driver *p; list_for_each_entry(p, &tty_drivers, tty_drivers) { dev_t base = MKDEV(p->major, p->minor_start); if (device < base || device >= base + p->num) continue; *index = device - base; return p; } return NULL; } #ifdef CONFIG_CONSOLE_POLL /** * tty_find_polling_driver - find device of a polled tty * @name: name string to match * @line: pointer to resulting tty line nr * * This routine returns a tty driver structure, given a name * and the condition that the tty driver is capable of polled * operation. */ struct tty_driver *tty_find_polling_driver(char *name, int *line) { struct tty_driver *p, *res = NULL; int tty_line = 0; int len; char *str; for (str = name; *str; str++) if ((*str >= '0' && *str <= '9') || *str == ',') break; if (!*str) return NULL; len = str - name; tty_line = simple_strtoul(str, &str, 10); mutex_lock(&tty_mutex); /* Search through the tty devices to look for a match */ list_for_each_entry(p, &tty_drivers, tty_drivers) { if (strncmp(name, p->name, len) != 0) continue; if (*str == ',') str++; if (*str == '\0') str = NULL; if (tty_line >= 0 && tty_line <= p->num && p->ops && p->ops->poll_init && !p->ops->poll_init(p, tty_line, str)) { res = p; *line = tty_line; break; } } mutex_unlock(&tty_mutex); return res; } EXPORT_SYMBOL_GPL(tty_find_polling_driver); #endif /** * tty_check_change - check for POSIX terminal changes * @tty: tty to check * * If we try to write to, or set the state of, a terminal and we're * not in the foreground, send a SIGTTOU. If the signal is blocked or * ignored, go ahead and perform the operation. (POSIX 7.2) * * Locking: ctrl_lock */ int tty_check_change(struct tty_struct *tty) { unsigned long flags; int ret = 0; if (current->signal->tty != tty) return 0; spin_lock_irqsave(&tty->ctrl_lock, flags); if (!tty->pgrp) { printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n"); goto out_unlock; } if (task_pgrp(current) == tty->pgrp) goto out_unlock; spin_unlock_irqrestore(&tty->ctrl_lock, flags); if (is_ignored(SIGTTOU)) goto out; if (is_current_pgrp_orphaned()) { ret = -EIO; goto out; } kill_pgrp(task_pgrp(current), SIGTTOU, 1); set_thread_flag(TIF_SIGPENDING); ret = -ERESTARTSYS; out: return ret; out_unlock: spin_unlock_irqrestore(&tty->ctrl_lock, flags); return ret; } EXPORT_SYMBOL(tty_check_change); static ssize_t hung_up_tty_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { return 0; } static ssize_t hung_up_tty_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { return -EIO; } /* No kernel lock held - none needed ;) */ static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait) { return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM; } static long hung_up_tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { return cmd == TIOCSPGRP ? -ENOTTY : -EIO; } static long hung_up_tty_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { return cmd == TIOCSPGRP ? -ENOTTY : -EIO; } static const struct file_operations tty_fops = { .llseek = no_llseek, .read = tty_read, .write = tty_write, .poll = tty_poll, .unlocked_ioctl = tty_ioctl, .compat_ioctl = tty_compat_ioctl, .open = tty_open, .release = tty_release, .fasync = tty_fasync, }; #ifdef CONFIG_UNIX98_PTYS static const struct file_operations ptmx_fops = { .llseek = no_llseek, .read = tty_read, .write = tty_write, .poll = tty_poll, .unlocked_ioctl = tty_ioctl, .compat_ioctl = tty_compat_ioctl, .open = ptmx_open, .release = tty_release, .fasync = tty_fasync, }; #endif static const struct file_operations console_fops = { .llseek = no_llseek, .read = tty_read, .write = redirected_tty_write, .poll = tty_poll, .unlocked_ioctl = tty_ioctl, .compat_ioctl = tty_compat_ioctl, .open = tty_open, .release = tty_release, .fasync = tty_fasync, }; static const struct file_operations hung_up_tty_fops = { .llseek = no_llseek, .read = hung_up_tty_read, .write = hung_up_tty_write, .poll = hung_up_tty_poll, .unlocked_ioctl = hung_up_tty_ioctl, .compat_ioctl = hung_up_tty_compat_ioctl, .release = tty_release, }; static DEFINE_SPINLOCK(redirect_lock); static struct file *redirect; /** * tty_wakeup - request more data * @tty: terminal * * Internal and external helper for wakeups of tty. This function * informs the line discipline if present that the driver is ready * to receive more output data. */ void tty_wakeup(struct tty_struct *tty) { struct tty_ldisc *ld; if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) { ld = tty_ldisc_ref(tty); if (ld) { if (ld->ops->write_wakeup) ld->ops->write_wakeup(tty); tty_ldisc_deref(ld); } } wake_up_interruptible(&tty->write_wait); } EXPORT_SYMBOL_GPL(tty_wakeup); /** * tty_ldisc_flush - flush line discipline queue * @tty: tty * * Flush the line discipline queue (if any) for this tty. If there * is no line discipline active this is a no-op. */ void tty_ldisc_flush(struct tty_struct *tty) { struct tty_ldisc *ld = tty_ldisc_ref(tty); if (ld) { if (ld->ops->flush_buffer) ld->ops->flush_buffer(tty); tty_ldisc_deref(ld); } tty_buffer_flush(tty); } EXPORT_SYMBOL_GPL(tty_ldisc_flush); /** * tty_reset_termios - reset terminal state * @tty: tty to reset * * Restore a terminal to the driver default state */ static void tty_reset_termios(struct tty_struct *tty) { mutex_lock(&tty->termios_mutex); *tty->termios = tty->driver->init_termios; tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios); tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios); mutex_unlock(&tty->termios_mutex); } /** * do_tty_hangup - actual handler for hangup events * @work: tty device * * This can be called by the "eventd" kernel thread. That is process * synchronous but doesn't hold any locks, so we need to make sure we * have the appropriate locks for what we're doing. * * The hangup event clears any pending redirections onto the hung up * device. It ensures future writes will error and it does the needed * line discipline hangup and signal delivery. The tty object itself * remains intact. * * Locking: * BKL * redirect lock for undoing redirection * file list lock for manipulating list of ttys * tty_ldisc_lock from called functions * termios_mutex resetting termios data * tasklist_lock to walk task list for hangup event * ->siglock to protect ->signal/->sighand */ static void do_tty_hangup(struct work_struct *work) { struct tty_struct *tty = container_of(work, struct tty_struct, hangup_work); struct file *cons_filp = NULL; struct file *filp, *f = NULL; struct task_struct *p; struct tty_ldisc *ld; int closecount = 0, n; unsigned long flags; if (!tty) return; /* inuse_filps is protected by the single kernel lock */ lock_kernel(); spin_lock(&redirect_lock); if (redirect && redirect->private_data == tty) { f = redirect; redirect = NULL; } spin_unlock(&redirect_lock); check_tty_count(tty, "do_tty_hangup"); file_list_lock(); /* This breaks for file handles being sent over AF_UNIX sockets ? */ list_for_each_entry(filp, &tty->tty_files, f_u.fu_list) { if (filp->f_op->write == redirected_tty_write) cons_filp = filp; if (filp->f_op->write != tty_write) continue; closecount++; tty_fasync(-1, filp, 0); /* can't block */ filp->f_op = &hung_up_tty_fops; } file_list_unlock(); /* * FIXME! What are the locking issues here? This may me overdoing * things... This question is especially important now that we've * removed the irqlock. */ ld = tty_ldisc_ref(tty); if (ld != NULL) { /* We may have no line discipline at this point */ if (ld->ops->flush_buffer) ld->ops->flush_buffer(tty); tty_driver_flush_buffer(tty); if ((test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) && ld->ops->write_wakeup) ld->ops->write_wakeup(tty); if (ld->ops->hangup) ld->ops->hangup(tty); } /* * FIXME: Once we trust the LDISC code better we can wait here for * ldisc completion and fix the driver call race */ wake_up_interruptible(&tty->write_wait); wake_up_interruptible(&tty->read_wait); /* * Shutdown the current line discipline, and reset it to * N_TTY. */ if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) tty_reset_termios(tty); /* Defer ldisc switch */ /* tty_deferred_ldisc_switch(N_TTY); This should get done automatically when the port closes and tty_release is called */ read_lock(&tasklist_lock); if (tty->session) { do_each_pid_task(tty->session, PIDTYPE_SID, p) { spin_lock_irq(&p->sighand->siglock); if (p->signal->tty == tty) p->signal->tty = NULL; if (!p->signal->leader) { spin_unlock_irq(&p->sighand->siglock); continue; } __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p); __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p); put_pid(p->signal->tty_old_pgrp); /* A noop */ spin_lock_irqsave(&tty->ctrl_lock, flags); if (tty->pgrp) p->signal->tty_old_pgrp = get_pid(tty->pgrp); spin_unlock_irqrestore(&tty->ctrl_lock, flags); spin_unlock_irq(&p->sighand->siglock); } while_each_pid_task(tty->session, PIDTYPE_SID, p); } read_unlock(&tasklist_lock); spin_lock_irqsave(&tty->ctrl_lock, flags); tty->flags = 0; put_pid(tty->session); put_pid(tty->pgrp); tty->session = NULL; tty->pgrp = NULL; tty->ctrl_status = 0; spin_unlock_irqrestore(&tty->ctrl_lock, flags); /* * If one of the devices matches a console pointer, we * cannot just call hangup() because that will cause * tty->count and state->count to go out of sync. * So we just call close() the right number of times. */ if (cons_filp) { if (tty->ops->close) for (n = 0; n < closecount; n++) tty->ops->close(tty, cons_filp); } else if (tty->ops->hangup) (tty->ops->hangup)(tty); /* * We don't want to have driver/ldisc interactions beyond * the ones we did here. The driver layer expects no * calls after ->hangup() from the ldisc side. However we * can't yet guarantee all that. */ set_bit(TTY_HUPPED, &tty->flags); if (ld) { tty_ldisc_enable(tty); tty_ldisc_deref(ld); } unlock_kernel(); if (f) fput(f); } /** * tty_hangup - trigger a hangup event * @tty: tty to hangup * * A carrier loss (virtual or otherwise) has occurred on this like * schedule a hangup sequence to run after this event. */ void tty_hangup(struct tty_struct *tty) { #ifdef TTY_DEBUG_HANGUP char buf[64]; printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf)); #endif schedule_work(&tty->hangup_work); } EXPORT_SYMBOL(tty_hangup); /** * tty_vhangup - process vhangup * @tty: tty to hangup * * The user has asked via system call for the terminal to be hung up. * We do this synchronously so that when the syscall returns the process * is complete. That guarantee is necessary for security reasons. */ void tty_vhangup(struct tty_struct *tty) { #ifdef TTY_DEBUG_HANGUP char buf[64]; printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf)); #endif do_tty_hangup(&tty->hangup_work); } EXPORT_SYMBOL(tty_vhangup); /** * tty_hung_up_p - was tty hung up * @filp: file pointer of tty * * Return true if the tty has been subject to a vhangup or a carrier * loss */ int tty_hung_up_p(struct file *filp) { return (filp->f_op == &hung_up_tty_fops); } EXPORT_SYMBOL(tty_hung_up_p); static void session_clear_tty(struct pid *session) { struct task_struct *p; do_each_pid_task(session, PIDTYPE_SID, p) { proc_clear_tty(p); } while_each_pid_task(session, PIDTYPE_SID, p); } /** * disassociate_ctty - disconnect controlling tty * @on_exit: true if exiting so need to "hang up" the session * * This function is typically called only by the session leader, when * it wants to disassociate itself from its controlling tty. * * It performs the following functions: * (1) Sends a SIGHUP and SIGCONT to the foreground process group * (2) Clears the tty from being controlling the session * (3) Clears the controlling tty for all processes in the * session group. * * The argument on_exit is set to 1 if called when a process is * exiting; it is 0 if called by the ioctl TIOCNOTTY. * * Locking: * BKL is taken for hysterical raisins * tty_mutex is taken to protect tty * ->siglock is taken to protect ->signal/->sighand * tasklist_lock is taken to walk process list for sessions * ->siglock is taken to protect ->signal/->sighand */ void disassociate_ctty(int on_exit) { struct tty_struct *tty; struct pid *tty_pgrp = NULL; mutex_lock(&tty_mutex); tty = get_current_tty(); if (tty) { tty_pgrp = get_pid(tty->pgrp); lock_kernel(); mutex_unlock(&tty_mutex); /* XXX: here we race, there is nothing protecting tty */ if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY) tty_vhangup(tty); unlock_kernel(); } 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); } mutex_unlock(&tty_mutex); return; } if (tty_pgrp) { kill_pgrp(tty_pgrp, SIGHUP, on_exit); if (!on_exit) kill_pgrp(tty_pgrp, SIGCONT, on_exit); put_pid(tty_pgrp); } spin_lock_irq(¤t->sighand->siglock); put_pid(current->signal->tty_old_pgrp); current->signal->tty_old_pgrp = NULL; spin_unlock_irq(¤t->sighand->siglock); mutex_lock(&tty_mutex); /* It is possible that do_tty_hangup has free'd this tty */ tty = get_current_tty(); if (tty) { unsigned long flags; spin_lock_irqsave(&tty->ctrl_lock, flags); put_pid(tty->session); put_pid(tty->pgrp); tty->session = NULL; tty->pgrp = NULL; spin_unlock_irqrestore(&tty->ctrl_lock, flags); } else { #ifdef TTY_DEBUG_HANGUP printk(KERN_DEBUG "error attempted to write to tty [0x%p]" " = NULL", tty); #endif } mutex_unlock(&tty_mutex); /* Now clear signal->tty under the lock */ read_lock(&tasklist_lock); session_clear_tty(task_session(current)); read_unlock(&tasklist_lock); } /** * * no_tty - Ensure the current process does not have a controlling tty */ void no_tty(void) { struct task_struct *tsk = current; lock_kernel(); if (tsk->signal->leader) disassociate_ctty(0); unlock_kernel(); proc_clear_tty(tsk); } /** * stop_tty - propagate flow control * @tty: tty to stop * * Perform flow control to the driver. For PTY/TTY pairs we * must also propagate the TIOCKPKT status. May be called * on an already stopped device and will not re-call the driver * method. * * This functionality is used by both the line disciplines for * halting incoming flow and by the driver. It may therefore be * called from any context, may be under the tty atomic_write_lock * but not always. * * Locking: * Uses the tty control lock internally */ void stop_tty(struct tty_struct *tty) { unsigned long flags; spin_lock_irqsave(&tty->ctrl_lock, flags); if (tty->stopped) { spin_unlock_irqrestore(&tty->ctrl_lock, flags); return; } tty->stopped = 1; if (tty->link && tty->link->packet) { tty->ctrl_status &= ~TIOCPKT_START; tty->ctrl_status |= TIOCPKT_STOP; wake_up_interruptible(&tty->link->read_wait); } spin_unlock_irqrestore(&tty->ctrl_lock, flags); if (tty->ops->stop) (tty->ops->stop)(tty); } EXPORT_SYMBOL(stop_tty); /** * start_tty - propagate flow control * @tty: tty to start * * Start a tty that has been stopped if at all possible. Perform * any necessary wakeups and propagate the TIOCPKT status. If this * is the tty was previous stopped and is being started then the * driver start method is invoked and the line discipline woken. * * Locking: * ctrl_lock */ void start_tty(struct tty_struct *tty) { unsigned long flags; spin_lock_irqsave(&tty->ctrl_lock, flags); if (!tty->stopped || tty->flow_stopped) { spin_unlock_irqrestore(&tty->ctrl_lock, flags); return; } tty->stopped = 0; if (tty->link && tty->link->packet) { tty->ctrl_status &= ~TIOCPKT_STOP; tty->ctrl_status |= TIOCPKT_START; wake_up_interruptible(&tty->link->read_wait); } spin_unlock_irqrestore(&tty->ctrl_lock, flags); if (tty->ops->start) (tty->ops->start)(tty); /* If we have a running line discipline it may need kicking */ tty_wakeup(tty); } EXPORT_SYMBOL(start_tty); /** * tty_read - read method for tty device files * @file: pointer to tty file * @buf: user buffer * @count: size of user buffer * @ppos: unused * * Perform the read system call function on this terminal device. Checks * for hung up devices before calling the line discipline method. * * Locking: * Locks the line discipline internally while needed. Multiple * read calls may be outstanding in parallel. */ static ssize_t tty_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { int i; struct tty_struct *tty; struct inode *inode; struct tty_ldisc *ld; tty = (struct tty_struct *)file->private_data; inode = file->f_path.dentry->d_inode; if (tty_paranoia_check(tty, inode, "tty_read")) return -EIO; if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags))) return -EIO; /* We want to wait for the line discipline to sort out in this situation */ ld = tty_ldisc_ref_wait(tty); if (ld->ops->read) i = (ld->ops->read)(tty, file, buf, count); else i = -EIO; tty_ldisc_deref(ld); if (i > 0) inode->i_atime = current_fs_time(inode->i_sb); return i; } void tty_write_unlock(struct tty_struct *tty) { mutex_unlock(&tty->atomic_write_lock); wake_up_interruptible(&tty->write_wait); } int tty_write_lock(struct tty_struct *tty, int ndelay) { if (!mutex_trylock(&tty->atomic_write_lock)) { if (ndelay) return -EAGAIN; if (mutex_lock_interruptible(&tty->atomic_write_lock)) return -ERESTARTSYS; } return 0; } /* * Split writes up in sane blocksizes to avoid * denial-of-service type attacks */ static inline ssize_t do_tty_write( ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t), struct tty_struct *tty, struct file *file, const char __user *buf, size_t count) { ssize_t ret, written = 0; unsigned int chunk; ret = tty_write_lock(tty, file->f_flags & O_NDELAY); if (ret < 0) return ret; /* * We chunk up writes into a temporary buffer. This * simplifies low-level drivers immensely, since they * don't have locking issues and user mode accesses. * * But if TTY_NO_WRITE_SPLIT is set, we should use a * big chunk-size.. * * The default chunk-size is 2kB, because the NTTY * layer has problems with bigger chunks. It will * claim to be able to handle more characters than * it actually does. * * FIXME: This can probably go away now except that 64K chunks * are too likely to fail unless switched to vmalloc... */ chunk = 2048; if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags)) chunk = 65536; if (count < chunk) chunk = count; /* write_buf/write_cnt is protected by the atomic_write_lock mutex */ if (tty->write_cnt < chunk) { unsigned char *buf; if (chunk < 1024) chunk = 1024; buf = kmalloc(chunk, GFP_KERNEL); if (!buf) { ret = -ENOMEM; goto out; } kfree(tty->write_buf); tty->write_cnt = chunk; tty->write_buf = buf; } /* Do the write .. */ for (;;) { size_t size = count; if (size > chunk) size = chunk; ret = -EFAULT; if (copy_from_user(tty->write_buf, buf, size)) break; ret = write(tty, file, tty->write_buf, size); if (ret <= 0) break; written += ret; buf += ret; count -= ret; if (!count) break; ret = -ERESTARTSYS; if (signal_pending(current)) break; cond_resched(); } if (written) { struct inode *inode = file->f_path.dentry->d_inode; inode->i_mtime = current_fs_time(inode->i_sb); ret = written; } out: tty_write_unlock(tty); return ret; } /** * tty_write - write method for tty device file * @file: tty file pointer * @buf: user data to write * @count: bytes to write * @ppos: unused * * Write data to a tty device via the line discipline. * * Locking: * Locks the line discipline as required * Writes to the tty driver are serialized by the atomic_write_lock * and are then processed in chunks to the device. The line discipline * write method will not be involked in parallel for each device * The line discipline write method is called under the big * kernel lock for historical reasons. New code should not rely on this. */ static ssize_t tty_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { struct tty_struct *tty; struct inode *inode = file->f_path.dentry->d_inode; ssize_t ret; struct tty_ldisc *ld; tty = (struct tty_struct *)file->private_data; if (tty_paranoia_check(tty, inode, "tty_write")) return -EIO; if (!tty || !tty->ops->write || (test_bit(TTY_IO_ERROR, &tty->flags))) return -EIO; /* Short term debug to catch buggy drivers */ if (tty->ops->write_room == NULL) printk(KERN_ERR "tty driver %s lacks a write_room method.\n", tty->driver->name); ld = tty_ldisc_ref_wait(tty); if (!ld->ops->write) ret = -EIO; else ret = do_tty_write(ld->ops->write, tty, file, buf, count); tty_ldisc_deref(ld); return ret; } ssize_t redirected_tty_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { struct file *p = NULL; spin_lock(&redirect_lock); if (redirect) { get_file(redirect); p = redirect; } spin_unlock(&redirect_lock); if (p) { ssize_t res; res = vfs_write(p, buf, count, &p->f_pos); fput(p); return res; } return tty_write(file, buf, count, ppos); } static char ptychar[] = "pqrstuvwxyzabcde"; /** * pty_line_name - generate name for a pty * @driver: the tty driver in use * @index: the minor number * @p: output buffer of at least 6 bytes * * Generate a name from a driver reference and write it to the output * buffer. * * Locking: None */ static void pty_line_name(struct tty_driver *driver, int index, char *p) { int i = index + driver->name_base; /* ->name is initialized to "ttyp", but "tty" is expected */ sprintf(p, "%s%c%x", driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name, ptychar[i >> 4 & 0xf], i & 0xf); } /** * pty_line_name - generate name for a tty * @driver: the tty driver in use * @index: the minor number * @p: output buffer of at least 7 bytes * * Generate a name from a driver reference and write it to the output * buffer. * * Locking: None */ static void tty_line_name(struct tty_driver *driver, int index, char *p) { sprintf(p, "%s%d", driver->name, index + driver->name_base); } /** * init_dev - initialise a tty device * @driver: tty driver we are opening a device on * @idx: device index * @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. */ static int init_dev(struct tty_driver *driver, int idx, struct tty_struct **ret_tty) { struct tty_struct *tty, *o_tty; struct ktermios *tp, **tp_loc, *o_tp, **o_tp_loc; struct ktermios *ltp, **ltp_loc, *o_ltp, **o_ltp_loc; int retval = 0; /* check whether we're reopening an existing tty */ if (driver->flags & TTY_DRIVER_DEVPTS_MEM) { tty = devpts_get_tty(idx); /* * If we don't have a tty here on a slave open, it's because * the master already started the close process and there's * no relation between devpts file and tty anymore. */ if (!tty && driver->subtype == PTY_TYPE_SLAVE) { retval = -EIO; goto end_init; } /* * It's safe from now on because init_dev() is called with * tty_mutex held and release_dev() won't change tty->count * or tty->flags without having to grab tty_mutex */ if (tty && driver->subtype == PTY_TYPE_MASTER) tty = tty->link; } else { tty = driver->ttys[idx]; } if (tty) goto fast_track; /* * First time open is complex, especially for PTY devices. * This code guarantees that either everything succeeds and the * TTY is ready for operation, or else the table slots are vacated * and the allocated memory released. (Except that the termios * and locked termios may be retained.) */ if (!try_module_get(driver->owner)) { retval = -ENODEV; goto end_init; } o_tty = NULL; tp = o_tp = NULL; ltp = o_ltp = NULL; tty = alloc_tty_struct(); if (!tty) goto fail_no_mem; initialize_tty_struct(tty); tty->driver = driver; tty->ops = driver->ops; tty->index = idx; tty_line_name(driver, idx, tty->name); if (driver->flags & TTY_DRIVER_DEVPTS_MEM) { tp_loc = &tty->termios; ltp_loc = &tty->termios_locked; } else { tp_loc = &driver->termios[idx]; ltp_loc = &driver->termios_locked[idx]; } if (!*tp_loc) { tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL); if (!tp) goto free_mem_out; *tp = driver->init_termios; } if (!*ltp_loc) { ltp = kzalloc(sizeof(struct ktermios), GFP_KERNEL); if (!ltp) goto free_mem_out; } if (driver->type == TTY_DRIVER_TYPE_PTY) { o_tty = alloc_tty_struct(); if (!o_tty) goto free_mem_out; initialize_tty_struct(o_tty); o_tty->driver = driver->other; o_tty->ops = driver->ops; o_tty->index = idx; tty_line_name(driver->other, idx, o_tty->name); if (driver->flags & TTY_DRIVER_DEVPTS_MEM) { o_tp_loc = &o_tty->termios; o_ltp_loc = &o_tty->termios_locked; } else { o_tp_loc = &driver->other->termios[idx]; o_ltp_loc = &driver->other->termios_locked[idx]; } if (!*o_tp_loc) { o_tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL); if (!o_tp) goto free_mem_out; *o_tp = driver->other->init_termios; } if (!*o_ltp_loc) { o_ltp = kzalloc(sizeof(struct ktermios), GFP_KERNEL); if (!o_ltp) goto free_mem_out; } /* * Everything allocated ... set up the o_tty structure. */ if (!(driver->other->flags & TTY_DRIVER_DEVPTS_MEM)) driver->other->ttys[idx] = o_tty; if (!*o_tp_loc) *o_tp_loc = o_tp; if (!*o_ltp_loc) *o_ltp_loc = o_ltp; o_tty->termios = *o_tp_loc; o_tty->termios_locked = *o_ltp_loc; driver->other->refcount++; if (driver->subtype == PTY_TYPE_MASTER) o_tty->count++; /* Establish the links in both directions */ tty->link = o_tty; o_tty->link = tty; } /* * All structures have been allocated, so now we install them. * Failures after this point use release_tty to clean up, so * there's no need to null out the local pointers. */ if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM)) driver->ttys[idx] = tty; if (!*tp_loc) *tp_loc = tp; if (!*ltp_loc) *ltp_loc = ltp; tty->termios = *tp_loc; tty->termios_locked = *ltp_loc; /* 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); driver->refcount++; tty->count++; /* * 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, o_tty); if (retval) goto release_mem_out; goto success; /* * This fast open can be used if the tty is already open. * No memory is allocated, and the only failures are from * attempting to open a closing tty or attempting multiple * opens on a pty master. */ fast_track: if (test_bit(TTY_CLOSING, &tty->flags)) { retval = -EIO; goto end_init; } if (driver->type == TTY_DRIVER_TYPE_PTY && driver->subtype == PTY_TYPE_MASTER) { /* * special case for PTY masters: only one open permitted, * and the slave side open count is incremented as well. */ if (tty->count) { retval = -EIO; goto end_init; } tty->link->count++; } tty->count++; tty->driver = driver; /* N.B. why do this every time?? */ /* FIXME */ if (!test_bit(TTY_LDISC, &tty->flags)) printk(KERN_ERR "init_dev but no ldisc\n"); success: *ret_tty = tty; /* All paths come through here to release the mutex */ end_init: return retval; /* Release locally allocated memory ... nothing placed in slots */ free_mem_out: kfree(o_tp); if (o_tty) free_tty_struct(o_tty); kfree(ltp); kfree(tp); free_tty_struct(tty); fail_no_mem: module_put(driver->owner); retval = -ENOMEM; goto end_init; /* call the tty release_tty routine to clean out this slot */ release_mem_out: if (printk_ratelimit()) printk(KERN_INFO "init_dev: ldisc open failed, " "clearing slot %d\n", idx); release_tty(tty, idx); goto end_init; } /** * release_one_tty - release tty structure memory * * Releases memory associated with a tty structure, and clears out the * driver table slots. This function is called when a device is no longer * in use. It also gets called when setup of a device fails. * * Locking: * tty_mutex - sometimes only * takes the file list lock internally when working on the list * of ttys that the driver keeps. * FIXME: should we require tty_mutex is held here ?? */ static void release_one_tty(struct tty_struct *tty, int idx) { int devpts = tty->driver->flags & TTY_DRIVER_DEVPTS_MEM; struct ktermios *tp; if (!devpts) tty->driver->ttys[idx] = NULL; if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) { tp = tty->termios; if (!devpts) tty->driver->termios[idx] = NULL; kfree(tp); tp = tty->termios_locked; if (!devpts) tty->driver->termios_locked[idx] = NULL; kfree(tp); } tty->magic = 0; tty->driver->refcount--; file_list_lock(); list_del_init(&tty->tty_files); file_list_unlock(); free_tty_struct(tty); } /** * release_tty - release tty structure memory * * Release both @tty and a possible linked partner (think pty pair), * and decrement the refcount of the backing module. * * Locking: * tty_mutex - sometimes only * takes the file list lock internally when working on the list * of ttys that the driver keeps. * FIXME: should we require tty_mutex is held here ?? */ static void release_tty(struct tty_struct *tty, int idx) { struct tty_driver *driver = tty->driver; if (tty->link) release_one_tty(tty->link, idx); release_one_tty(tty, idx); module_put(driver->owner); } /* * 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. */ static void release_dev(struct file *filp) { struct tty_struct *tty, *o_tty; int pty_master, tty_closing, o_tty_closing, do_sleep; int devpts; int idx; char buf[64]; tty = (struct tty_struct *)filp->private_data; if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "release_dev")) return; check_tty_count(tty, "release_dev"); tty_fasync(-1, filp, 0); idx = tty->index; pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY && tty->driver->subtype == PTY_TYPE_MASTER); devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0; o_tty = tty->link; #ifdef TTY_PARANOIA_CHECK if (idx < 0 || idx >= tty->driver->num) { printk(KERN_DEBUG "release_dev: bad idx when trying to " "free (%s)\n", tty->name); return; } if (!(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) { if (tty != tty->driver->ttys[idx]) { printk(KERN_DEBUG "release_dev: driver.table[%d] not tty " "for (%s)\n", idx, tty->name); return; } if (tty->termios != tty->driver->termios[idx]) { printk(KERN_DEBUG "release_dev: driver.termios[%d] not termios " "for (%s)\n", idx, tty->name); return; } if (tty->termios_locked != tty->driver->termios_locked[idx]) { printk(KERN_DEBUG "release_dev: driver.termios_locked[%d] not " "termios_locked for (%s)\n", idx, tty->name); return; } } #endif #ifdef TTY_DEBUG_HANGUP printk(KERN_DEBUG "release_dev of %s (tty count=%d)...", tty_name(tty, buf), tty->count); #endif #ifdef TTY_PARANOIA_CHECK if (tty->driver->other && !(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) { if (o_tty != tty->driver->other->ttys[idx]) { printk(KERN_DEBUG "release_dev: other->table[%d] " "not o_tty for (%s)\n", idx, tty->name); return; } if (o_tty->termios != tty->driver->other->termios[idx]) { printk(KERN_DEBUG "release_dev: other->termios[%d] " "not o_termios for (%s)\n", idx, tty->name); return; } if (o_tty->termios_locked != tty->driver->other->termios_locked[idx]) { printk(KERN_DEBUG "release_dev: other->termios_locked[" "%d] not o_termios_locked for (%s)\n", idx, tty->name); return; } if (o_tty->link != tty) { printk(KERN_DEBUG "release_dev: bad pty pointers\n"); return; } } #endif if (tty->ops->close) tty->ops->close(tty, filp); /* * Sanity check: if tty->count is going to zero, there shouldn't be * any waiters on tty->read_wait or tty->write_wait. We test the * wait queues and kick everyone out _before_ actually starting to * close. This ensures that we won't block while releasing the tty * structure. * * The test for the o_tty closing is necessary, since the master and * slave sides may close in any order. If the slave side closes out * first, its count will be one, since the master side holds an open. * Thus this test wouldn't be triggered at the time the slave closes, * so we do it now. * * Note that it's possible for the tty to be opened again while we're * flushing out waiters. By recalculating the closing flags before * each iteration we avoid any problems. */ while (1) { /* Guard against races with tty->count changes elsewhere and opens on /dev/tty */ mutex_lock(&tty_mutex); tty_closing = tty->count <= 1; o_tty_closing = o_tty && (o_tty->count <= (pty_master ? 1 : 0)); do_sleep = 0; if (tty_closing) { if (waitqueue_active(&tty->read_wait)) { wake_up(&tty->read_wait); do_sleep++; } if (waitqueue_active(&tty->write_wait)) { wake_up(&tty->write_wait); do_sleep++; } } if (o_tty_closing) { if (waitqueue_active(&o_tty->read_wait)) { wake_up(&o_tty->read_wait); do_sleep++; } if (waitqueue_active(&o_tty->write_wait)) { wake_up(&o_tty->write_wait); do_sleep++; } } if (!do_sleep) break; printk(KERN_WARNING "release_dev: %s: read/write wait queue " "active!\n", tty_name(tty, buf)); mutex_unlock(&tty_mutex); schedule(); } /* * The closing flags are now consistent with the open counts on * both sides, and we've completed the last operation that could * block, so it's safe to proceed with closing. */ if (pty_master) { if (--o_tty->count < 0) { printk(KERN_WARNING "release_dev: bad pty slave count " "(%d) for %s\n", o_tty->count, tty_name(o_tty, buf)); o_tty->count = 0; } } if (--tty->count < 0) { printk(KERN_WARNING "release_dev: bad tty->count (%d) for %s\n", tty->count, tty_name(tty, buf)); tty->count = 0; } /* * We've decremented tty->count, so we need to remove this file * descriptor off the tty->tty_files list; this serves two * purposes: * - check_tty_count sees the correct number of file descriptors * associated with this tty. * - do_tty_hangup no longer sees this file descriptor as * something that needs to be handled for hangups. */ file_kill(filp); filp->private_data = NULL; /* * Perform some housekeeping before deciding whether to return. * * Set the TTY_CLOSING flag if this was the last open. In the * case of a pty we may have to wait around for the other side * to close, and TTY_CLOSING makes sure we can't be reopened. */ if (tty_closing) set_bit(TTY_CLOSING, &tty->flags); if (o_tty_closing) set_bit(TTY_CLOSING, &o_tty->flags); /* * If _either_ side is closing, make sure there aren't any * processes that still think tty or o_tty is their controlling * tty. */ if (tty_closing || o_tty_closing) { read_lock(&tasklist_lock); session_clear_tty(tty->session); if (o_tty) session_clear_tty(o_tty->session); read_unlock(&tasklist_lock); } mutex_unlock(&tty_mutex); /* check whether both sides are closing ... */ if (!tty_closing || (o_tty && !o_tty_closing)) return; #ifdef TTY_DEBUG_HANGUP printk(KERN_DEBUG "freeing tty structure..."); #endif /* * Ask the line discipline code to release its structures */ tty_ldisc_release(tty, o_tty); /* * The release_tty function takes care of the details of clearing * the slots and preserving the termios structure. */ release_tty(tty, idx); /* Make this pty number available for reallocation */ if (devpts) devpts_kill_index(idx); } /** * tty_open - open a tty device * @inode: inode of device file * @filp: file pointer to tty * * tty_open and tty_release keep up the tty count that contains the * number of opens done on a tty. We cannot use the inode-count, as * different inodes might point to the same tty. * * Open-counting is needed for pty masters, as well as for keeping * track of serial lines: DTR is dropped when the last close happens. * (This is not done solely through tty->count, now. - Ted 1/27/92) * * The termios state of a pty is reset on first open so that * settings don't persist across reuse. * * Locking: tty_mutex protects tty, get_tty_driver and init_dev work. * tty->count should protect the rest. * ->siglock protects ->signal/->sighand */ static int __tty_open(struct inode *inode, struct file *filp) { struct tty_struct *tty; int noctty, retval; struct tty_driver *driver; int index; dev_t device = inode->i_rdev; unsigned short saved_flags = filp->f_flags; nonseekable_open(inode, filp); retry_open: noctty = filp->f_flags & O_NOCTTY; index = -1; retval = 0; mutex_lock(&tty_mutex); if (device == MKDEV(TTYAUX_MAJOR, 0)) { tty = get_current_tty(); if (!tty) { mutex_unlock(&tty_mutex); return -ENXIO; } driver = tty->driver; index = tty->index; filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */ /* noctty = 1; */ goto got_driver; } #ifdef CONFIG_VT if (device == MKDEV(TTY_MAJOR, 0)) { extern struct tty_driver *console_driver; driver = console_driver; index = fg_console; noctty = 1; goto got_driver; } #endif if (device == MKDEV(TTYAUX_MAJOR, 1)) { driver = console_device(&index); if (driver) { /* Don't let /dev/console block */ filp->f_flags |= O_NONBLOCK; noctty = 1; goto got_driver; } mutex_unlock(&tty_mutex); return -ENODEV; } driver = get_tty_driver(device, &index); if (!driver) { mutex_unlock(&tty_mutex); return -ENODEV; } got_driver: retval = init_dev(driver, index, &tty); mutex_unlock(&tty_mutex); if (retval) return retval; filp->private_data = tty; file_move(filp, &tty->tty_files); check_tty_count(tty, "tty_open"); if (tty->driver->type == TTY_DRIVER_TYPE_PTY && tty->driver->subtype == PTY_TYPE_MASTER) noctty = 1; #ifdef TTY_DEBUG_HANGUP printk(KERN_DEBUG "opening %s...", tty->name); #endif if (!retval) { if (tty->ops->open) retval = tty->ops->open(tty, filp); else retval = -ENODEV; } filp->f_flags = saved_flags; if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN)) retval = -EBUSY; if (retval) { #ifdef TTY_DEBUG_HANGUP printk(KERN_DEBUG "error %d in opening %s...", retval, tty->name); #endif release_dev(filp); if (retval != -ERESTARTSYS) return retval; if (signal_pending(current)) return retval; schedule(); /* * Need to reset f_op in case a hangup happened. */ if (filp->f_op == &hung_up_tty_fops) filp->f_op = &tty_fops; goto retry_open; } mutex_lock(&tty_mutex); spin_lock_irq(¤t->sighand->siglock); if (!noctty && current->signal->leader && !current->signal->tty && tty->session == NULL) __proc_set_tty(current, tty); spin_unlock_irq(¤t->sighand->siglock); mutex_unlock(&tty_mutex); return 0; } /* BKL pushdown: scary code avoidance wrapper */ static int tty_open(struct inode *inode, struct file *filp) { int ret; lock_kernel(); ret = __tty_open(inode, filp); unlock_kernel(); return ret; } #ifdef CONFIG_UNIX98_PTYS /** * ptmx_open - open a unix 98 pty master * @inode: inode of device file * @filp: file pointer to tty * * Allocate a unix98 pty master device from the ptmx driver. * * Locking: tty_mutex protects theinit_dev work. tty->count should * protect the rest. * allocated_ptys_lock handles the list of free pty numbers */ static int __ptmx_open(struct inode *inode, struct file *filp) { struct tty_struct *tty; int retval; int index; nonseekable_open(inode, filp); /* find a device that is not in use. */ index = devpts_new_index(); if (index < 0) return index; mutex_lock(&tty_mutex); retval = init_dev(ptm_driver, index, &tty); mutex_unlock(&tty_mutex); if (retval) goto out; set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */ filp->private_data = tty; file_move(filp, &tty->tty_files); retval = devpts_pty_new(tty->link); if (retval) goto out1; check_tty_count(tty, "ptmx_open"); retval = ptm_driver->ops->open(tty, filp); if (!retval) return 0; out1: release_dev(filp); return retval; out: devpts_kill_index(index); return retval; } static int ptmx_open(struct inode *inode, struct file *filp) { int ret; lock_kernel(); ret = __ptmx_open(inode, filp); unlock_kernel(); return ret; } #endif /** * 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 release_dev */ static int tty_release(struct inode *inode, struct file *filp) { lock_kernel(); release_dev(filp); unlock_kernel(); return 0; } /** * tty_poll - check tty status * @filp: file being polled * @wait: poll wait structures to update * * Call the line discipline polling method to obtain the poll * status of the device. * * Locking: locks called line discipline but ldisc poll method * may be re-entered freely by other callers. */ static unsigned int tty_poll(struct file *filp, poll_table *wait) { struct tty_struct *tty; struct tty_ldisc *ld; int ret = 0; tty = (struct tty_struct *)filp->private_data; if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll")) return 0; ld = tty_ldisc_ref_wait(tty); if (ld->ops->poll) ret = (ld->ops->poll)(tty, filp, wait); tty_ldisc_deref(ld); return ret; } static int tty_fasync(int fd, struct file *filp, int on) { struct tty_struct *tty; unsigned long flags; int retval = 0; lock_kernel(); tty = (struct tty_struct *)filp->private_data; if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync")) goto out; retval = fasync_helper(fd, filp, on, &tty->fasync); if (retval <= 0) goto out; if (on) { enum pid_type type; struct pid *pid; if (!waitqueue_active(&tty->read_wait)) tty->minimum_to_wake = 1; spin_lock_irqsave(&tty->ctrl_lock, flags); if (tty->pgrp) { pid = tty->pgrp; type = PIDTYPE_PGID; } else { pid = task_pid(current); type = PIDTYPE_PID; } spin_unlock_irqrestore(&tty->ctrl_lock, flags); retval = __f_setown(filp, pid, type, 0); if (retval) goto out; } else { if (!tty->fasync && !waitqueue_active(&tty->read_wait)) tty->minimum_to_wake = N_TTY_BUF_SIZE; } retval = 0; out: unlock_kernel(); return retval; } /** * tiocsti - fake input character * @tty: tty to fake input into * @p: pointer to character * * Fake input to a tty device. Does the necessary locking and * input management. * * FIXME: does not honour flow control ?? * * Locking: * Called functions take tty_ldisc_lock * current->signal->tty check is safe without locks * * FIXME: may race normal receive processing */ static int tiocsti(struct tty_struct *tty, char __user *p) { char ch, mbz = 0; struct tty_ldisc *ld; if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN)) return -EPERM; if (get_user(ch, p)) return -EFAULT; ld = tty_ldisc_ref_wait(tty); ld->ops->receive_buf(tty, &ch, &mbz, 1); tty_ldisc_deref(ld); return 0; } /** * tiocgwinsz - implement window query ioctl * @tty; tty * @arg: user buffer for result * * Copies the kernel idea of the window size into the user buffer. * * Locking: tty->termios_mutex is taken to ensure the winsize data * is consistent. */ static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg) { int err; mutex_lock(&tty->termios_mutex); err = copy_to_user(arg, &tty->winsize, sizeof(*arg)); mutex_unlock(&tty->termios_mutex); return err ? -EFAULT: 0; } /** * tty_do_resize - resize event * @tty: tty being resized * @real_tty: real tty (not the same as tty if using a pty/tty pair) * @rows: rows (character) * @cols: cols (character) * * Update the termios variables and send the neccessary signals to * peform a terminal resize correctly */ int tty_do_resize(struct tty_struct *tty, struct tty_struct *real_tty, struct winsize *ws) { struct pid *pgrp, *rpgrp; unsigned long flags; /* For a PTY we need to lock the tty side */ mutex_lock(&real_tty->termios_mutex); if (!memcmp(ws, &tty->winsize, sizeof(*ws))) goto done; /* Get the PID values and reference them so we can avoid holding the tty ctrl lock while sending signals */ spin_lock_irqsave(&tty->ctrl_lock, flags); pgrp = get_pid(tty->pgrp); rpgrp = get_pid(real_tty->pgrp); spin_unlock_irqrestore(&tty->ctrl_lock, flags); if (pgrp) kill_pgrp(pgrp, SIGWINCH, 1); if (rpgrp != pgrp && rpgrp) kill_pgrp(rpgrp, SIGWINCH, 1); put_pid(pgrp); put_pid(rpgrp); tty->winsize = *ws; real_tty->winsize = *ws; done: mutex_unlock(&real_tty->termios_mutex); return 0; } /** * tiocswinsz - implement window size set ioctl * @tty; tty * @arg: user buffer for result * * Copies the user idea of the window size to the kernel. Traditionally * this is just advisory information but for the Linux console it * actually has driver level meaning and triggers a VC resize. * * Locking: * Driver dependant. The default do_resize method takes the * tty termios mutex and ctrl_lock. The console takes its own lock * then calls into the default method. */ static int tiocswinsz(struct tty_struct *tty, struct tty_struct *real_tty, struct winsize __user *arg) { struct winsize tmp_ws; if (copy_from_user(&tmp_ws, arg, sizeof(*arg))) return -EFAULT; if (tty->ops->resize) return tty->ops->resize(tty, real_tty, &tmp_ws); else return tty_do_resize(tty, real_tty, &tmp_ws); } /** * tioccons - allow admin to move logical console * @file: the file to become console * * Allow the adminstrator to move the redirected console device * * Locking: uses redirect_lock to guard the redirect information */ static int tioccons(struct file *file) { if (!capable(CAP_SYS_ADMIN)) return -EPERM; if (file->f_op->write == redirected_tty_write) { struct file *f; spin_lock(&redirect_lock); f = redirect; redirect = NULL; spin_unlock(&redirect_lock); if (f) fput(f); return 0; } spin_lock(&redirect_lock); if (redirect) { spin_unlock(&redirect_lock); return -EBUSY; } get_file(file); redirect = file; spin_unlock(&redirect_lock); return 0; } /** * fionbio - non blocking ioctl * @file: file to set blocking value * @p: user parameter * * Historical tty interfaces had a blocking control ioctl before * the generic functionality existed. This piece of history is preserved * in the expected tty API of posix OS's. * * Locking: none, the open fle handle ensures it won't go away. */ static int fionbio(struct file *file, int __user *p) { int nonblock; if (get_user(nonblock, p)) return -EFAULT; /* file->f_flags is still BKL protected in the fs layer - vomit */ lock_kernel(); if (nonblock) file->f_flags |= O_NONBLOCK; else file->f_flags &= ~O_NONBLOCK; unlock_kernel(); return 0; } /** * tiocsctty - set controlling tty * @tty: tty structure * @arg: user argument * * This ioctl is used to manage job control. It permits a session * leader to set this tty as the controlling tty for the session. * * Locking: * Takes tty_mutex() to protect tty instance * Takes tasklist_lock internally to walk sessions * Takes ->siglock() when updating signal->tty */ static int tiocsctty(struct tty_struct *tty, int arg) { int ret = 0; if (current->signal->leader && (task_session(current) == tty->session)) return ret; mutex_lock(&tty_mutex); /* * The process must be a session leader and * not have a controlling tty already. */ if (!current->signal->leader || current->signal->tty) { ret = -EPERM; goto unlock; } if (tty->session) { /* * This tty is already the controlling * tty for another session group! */ if (arg == 1 && capable(CAP_SYS_ADMIN)) { /* * Steal it away */ read_lock(&tasklist_lock); session_clear_tty(tty->session); read_unlock(&tasklist_lock); } else { ret = -EPERM; goto unlock; } } proc_set_tty(current, tty); unlock: mutex_unlock(&tty_mutex); return ret; } /** * tty_get_pgrp - return a ref counted pgrp pid * @tty: tty to read * * Returns a refcounted instance of the pid struct for the process * group controlling the tty. */ struct pid *tty_get_pgrp(struct tty_struct *tty) { unsigned long flags; struct pid *pgrp; spin_lock_irqsave(&tty->ctrl_lock, flags); pgrp = get_pid(tty->pgrp); spin_unlock_irqrestore(&tty->ctrl_lock, flags); return pgrp; } EXPORT_SYMBOL_GPL(tty_get_pgrp); /** * tiocgpgrp - get process group * @tty: tty passed by user * @real_tty: tty side of the tty pased by the user if a pty else the tty * @p: returned pid * * Obtain the process group of the tty. If there is no process group * return an error. * * Locking: none. Reference to current->signal->tty is safe. */ static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) { struct pid *pid; int ret; /* * (tty == real_tty) is a cheap way of * testing if the tty is NOT a master pty. */ if (tty == real_tty && current->signal->tty != real_tty) return -ENOTTY; pid = tty_get_pgrp(real_tty); ret = put_user(pid_vnr(pid), p); put_pid(pid); return ret; } /** * tiocspgrp - attempt to set process group * @tty: tty passed by user * @real_tty: tty side device matching tty passed by user * @p: pid pointer * * Set the process group of the tty to the session passed. Only * permitted where the tty session is our session. * * Locking: RCU, ctrl lock */ static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) { struct pid *pgrp; pid_t pgrp_nr; int retval = tty_check_change(real_tty); unsigned long flags; if (retval == -EIO) return -ENOTTY; if (retval) return retval; if (!current->signal->tty || (current->signal->tty != real_tty) || (real_tty->session != task_session(current))) return -ENOTTY; if (get_user(pgrp_nr, p)) return -EFAULT; if (pgrp_nr < 0) return -EINVAL; rcu_read_lock(); pgrp = find_vpid(pgrp_nr); retval = -ESRCH; if (!pgrp) goto out_unlock; retval = -EPERM; if (session_of_pgrp(pgrp) != task_session(current)) goto out_unlock; retval = 0; spin_lock_irqsave(&tty->ctrl_lock, flags); put_pid(real_tty->pgrp); real_tty->pgrp = get_pid(pgrp); spin_unlock_irqrestore(&tty->ctrl_lock, flags); out_unlock: rcu_read_unlock(); return retval; } /** * tiocgsid - get session id * @tty: tty passed by user * @real_tty: tty side of the tty pased by the user if a pty else the tty * @p: pointer to returned session id * * Obtain the session id of the tty. If there is no session * return an error. * * Locking: none. Reference to current->signal->tty is safe. */ static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) { /* * (tty == real_tty) is a cheap way of * testing if the tty is NOT a master pty. */ if (tty == real_tty && current->signal->tty != real_tty) return -ENOTTY; if (!real_tty->session) return -ENOTTY; return put_user(pid_vnr(real_tty->session), p); } /** * tiocsetd - set line discipline * @tty: tty device * @p: pointer to user data * * Set the line discipline according to user request. * * Locking: see tty_set_ldisc, this function is just a helper */ static int tiocsetd(struct tty_struct *tty, int __user *p) { int ldisc; int ret; if (get_user(ldisc, p)) return -EFAULT; lock_kernel(); ret = tty_set_ldisc(tty, ldisc); unlock_kernel(); return ret; } /** * send_break - performed time break * @tty: device to break on * @duration: timeout in mS * * Perform a timed break on hardware that lacks its own driver level * timed break functionality. * * Locking: * atomic_write_lock serializes * */ static int send_break(struct tty_struct *tty, unsigned int duration) { int retval; if (tty->ops->break_ctl == NULL) return 0; if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK) retval = tty->ops->break_ctl(tty, duration); else { /* Do the work ourselves */ if (tty_write_lock(tty, 0) < 0) return -EINTR; retval = tty->ops->break_ctl(tty, -1); if (retval) goto out; if (!signal_pending(current)) msleep_interruptible(duration); retval = tty->ops->break_ctl(tty, 0); out: tty_write_unlock(tty); if (signal_pending(current)) retval = -EINTR; } return retval; } /** * tty_tiocmget - get modem status * @tty: tty device * @file: user file pointer * @p: pointer to result * * Obtain the modem status bits from the tty driver if the feature * is supported. Return -EINVAL if it is not available. * * Locking: none (up to the driver) */ static int tty_tiocmget(struct tty_struct *tty, struct file *file, int __user *p) { int retval = -EINVAL; if (tty->ops->tiocmget) { retval = tty->ops->tiocmget(tty, file); if (retval >= 0) retval = put_user(retval, p); } return retval; } /** * tty_tiocmset - set modem status * @tty: tty device * @file: user file pointer * @cmd: command - clear bits, set bits or set all * @p: pointer to desired bits * * Set the modem status bits from the tty driver if the feature * is supported. Return -EINVAL if it is not available. * * Locking: none (up to the driver) */ static int tty_tiocmset(struct tty_struct *tty, struct file *file, unsigned int cmd, unsigned __user *p) { int retval; unsigned int set, clear, val; if (tty->ops->tiocmset == NULL) return -EINVAL; retval = get_user(val, p); if (retval) return retval; set = clear = 0; switch (cmd) { case TIOCMBIS: set = val; break; case TIOCMBIC: clear = val; break; case TIOCMSET: set = val; clear = ~val; break; } set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP; clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP; return tty->ops->tiocmset(tty, file, set, clear); } /* * Split this up, as gcc can choke on it otherwise.. */ long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { struct tty_struct *tty, *real_tty; void __user *p = (void __user *)arg; int retval; struct tty_ldisc *ld; struct inode *inode = file->f_dentry->d_inode; tty = (struct tty_struct *)file->private_data; if (tty_paranoia_check(tty, inode, "tty_ioctl")) return -EINVAL; real_tty = tty; if (tty->driver->type == TTY_DRIVER_TYPE_PTY && tty->driver->subtype == PTY_TYPE_MASTER) real_tty = tty->link; /* * Factor out some common prep work */ switch (cmd) { case TIOCSETD: case TIOCSBRK: case TIOCCBRK: case TCSBRK: case TCSBRKP: retval = tty_check_change(tty); if (retval) return retval; if (cmd != TIOCCBRK) { tty_wait_until_sent(tty, 0); if (signal_pending(current)) return -EINTR; } break; } /* * Now do the stuff. */ switch (cmd) { case TIOCSTI: return tiocsti(tty, p); case TIOCGWINSZ: return tiocgwinsz(tty, p); case TIOCSWINSZ: return tiocswinsz(tty, real_tty, p); case TIOCCONS: return real_tty != tty ? -EINVAL : tioccons(file); case FIONBIO: return fionbio(file, p); case TIOCEXCL: set_bit(TTY_EXCLUSIVE, &tty->flags); return 0; case TIOCNXCL: clear_bit(TTY_EXCLUSIVE, &tty->flags); return 0; case TIOCNOTTY: if (current->signal->tty != tty) return -ENOTTY; no_tty(); return 0; case TIOCSCTTY: return tiocsctty(tty, arg); case TIOCGPGRP: return tiocgpgrp(tty, real_tty, p); case TIOCSPGRP: return tiocspgrp(tty, real_tty, p); case TIOCGSID: return tiocgsid(tty, real_tty, p); case TIOCGETD: return put_user(tty->ldisc.ops->num, (int __user *)p); case TIOCSETD: return tiocsetd(tty, p); /* * Break handling */ case TIOCSBRK: /* Turn break on, unconditionally */ if (tty->ops->break_ctl) return tty->ops->break_ctl(tty, -1); return 0; case TIOCCBRK: /* Turn break off, unconditionally */ if (tty->ops->break_ctl) return tty->ops->break_ctl(tty, 0); return 0; case TCSBRK: /* SVID version: non-zero arg --> no break */ /* non-zero arg means wait for all output data * to be sent (performed above) but don't send break. * This is used by the tcdrain() termios function. */ if (!arg) return send_break(tty, 250); return 0; case TCSBRKP: /* support for POSIX tcsendbreak() */ return send_break(tty, arg ? arg*100 : 250); case TIOCMGET: return tty_tiocmget(tty, file, p); case TIOCMSET: case TIOCMBIC: case TIOCMBIS: return tty_tiocmset(tty, file, cmd, p); case TCFLSH: switch (arg) { case TCIFLUSH: case TCIOFLUSH: /* flush tty buffer and allow ldisc to process ioctl */ tty_buffer_flush(tty); break; } break; } if (tty->ops->ioctl) { retval = (tty->ops->ioctl)(tty, file, cmd, arg); if (retval != -ENOIOCTLCMD) return retval; } ld = tty_ldisc_ref_wait(tty); retval = -EINVAL; if (ld->ops->ioctl) { retval = ld->ops->ioctl(tty, file, cmd, arg); if (retval == -ENOIOCTLCMD) retval = -EINVAL; } tty_ldisc_deref(ld); return retval; } #ifdef CONFIG_COMPAT static long tty_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { struct inode *inode = file->f_dentry->d_inode; struct tty_struct *tty = file->private_data; struct tty_ldisc *ld; int retval = -ENOIOCTLCMD; if (tty_paranoia_check(tty, inode, "tty_ioctl")) return -EINVAL; if (tty->ops->compat_ioctl) { retval = (tty->ops->compat_ioctl)(tty, file, cmd, arg); if (retval != -ENOIOCTLCMD) return retval; } ld = tty_ldisc_ref_wait(tty); if (ld->ops->compat_ioctl) retval = ld->ops->compat_ioctl(tty, file, cmd, arg); tty_ldisc_deref(ld); return retval; } #endif /* * This implements the "Secure Attention Key" --- the idea is to * prevent trojan horses by killing all processes associated with this * tty when the user hits the "Secure Attention Key". Required for * super-paranoid applications --- see the Orange Book for more details. * * This code could be nicer; ideally it should send a HUP, wait a few * seconds, then send a INT, and then a KILL signal. But you then * have to coordinate with the init process, since all processes associated * with the current tty must be dead before the new getty is allowed * to spawn. * * Now, if it would be correct ;-/ The current code has a nasty hole - * it doesn't catch files in flight. We may send the descriptor to ourselves * via AF_UNIX socket, close it and later fetch from socket. FIXME. * * Nasty bug: do_SAK is being called in interrupt context. This can * deadlock. We punt it up to process context. AKPM - 16Mar2001 */ void __do_SAK(struct tty_struct *tty) { #ifdef TTY_SOFT_SAK tty_hangup(tty); #else struct task_struct *g, *p; struct pid *session; int i; struct file *filp; struct fdtable *fdt; if (!tty) return; session = tty->session; tty_ldisc_flush(tty); tty_driver_flush_buffer(tty); read_lock(&tasklist_lock); /* Kill the entire session */ do_each_pid_task(session, PIDTYPE_SID, p) { printk(KERN_NOTICE "SAK: killed process %d" " (%s): task_session_nr(p)==tty->session\n", task_pid_nr(p), p->comm); send_sig(SIGKILL, p, 1); } while_each_pid_task(session, PIDTYPE_SID, p); /* Now kill any processes that happen to have the * tty open. */ do_each_thread(g, p) { if (p->signal->tty == tty) { printk(KERN_NOTICE "SAK: killed process %d" " (%s): task_session_nr(p)==tty->session\n", task_pid_nr(p), p->comm); send_sig(SIGKILL, p, 1); continue; } task_lock(p); if (p->files) { /* * We don't take a ref to the file, so we must * hold ->file_lock instead. */ spin_lock(&p->files->file_lock); fdt = files_fdtable(p->files); for (i = 0; i < fdt->max_fds; i++) { filp = fcheck_files(p->files, i); if (!filp) continue; if (filp->f_op->read == tty_read && filp->private_data == tty) { printk(KERN_NOTICE "SAK: killed process %d" " (%s): fd#%d opened to the tty\n", task_pid_nr(p), p->comm, i); force_sig(SIGKILL, p); break; } } spin_unlock(&p->files->file_lock); } task_unlock(p); } while_each_thread(g, p); read_unlock(&tasklist_lock); #endif } static void do_SAK_work(struct work_struct *work) { struct tty_struct *tty = container_of(work, struct tty_struct, SAK_work); __do_SAK(tty); } /* * The tq handling here is a little racy - tty->SAK_work may already be queued. * Fortunately we don't need to worry, because if ->SAK_work is already queued, * the values which we write to it will be identical to the values which it * already has. --akpm */ void do_SAK(struct tty_struct *tty) { if (!tty) return; schedule_work(&tty->SAK_work); } EXPORT_SYMBOL(do_SAK); /** * initialize_tty_struct * @tty: tty to initialize * * This subroutine initializes a tty structure that has been newly * allocated. * * Locking: none - tty in question must not be exposed at this point */ static void initialize_tty_struct(struct tty_struct *tty) { memset(tty, 0, sizeof(struct tty_struct)); tty->magic = TTY_MAGIC; tty_ldisc_init(tty); tty->session = NULL; tty->pgrp = NULL; tty->overrun_time = jiffies; tty->buf.head = tty->buf.tail = NULL; tty_buffer_init(tty); mutex_init(&tty->termios_mutex); init_waitqueue_head(&tty->write_wait); init_waitqueue_head(&tty->read_wait); INIT_WORK(&tty->hangup_work, do_tty_hangup); mutex_init(&tty->atomic_read_lock); mutex_init(&tty->atomic_write_lock); spin_lock_init(&tty->read_lock); spin_lock_init(&tty->ctrl_lock); INIT_LIST_HEAD(&tty->tty_files); INIT_WORK(&tty->SAK_work, do_SAK_work); } /** * tty_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); static struct class *tty_class; /** * tty_register_device - register a tty device * @driver: the tty driver that describes the tty device * @index: the index in the tty driver for this tty device * @device: a struct device that is associated with this tty device. * This field is optional, if there is no known struct device * for this tty device it can be set to NULL safely. * * Returns a pointer to the struct device for this tty device * (or ERR_PTR(-EFOO) on error). * * This call is required to be made to register an individual tty device * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If * that bit is not set, this function should not be called by a tty * driver. * * Locking: ?? */ struct device *tty_register_device(struct tty_driver *driver, unsigned index, struct device *device) { char name[64]; dev_t dev = MKDEV(driver->major, driver->minor_start) + index; if (index >= driver->num) { printk(KERN_ERR "Attempt to register invalid tty line number " " (%d).\n", index); return ERR_PTR(-EINVAL); } if (driver->type == TTY_DRIVER_TYPE_PTY) pty_line_name(driver, index, name); else tty_line_name(driver, index, name); return device_create_drvdata(tty_class, device, dev, NULL, name); } /** * tty_unregister_device - unregister a tty device * @driver: the tty driver that describes the tty device * @index: the index in the tty driver for this tty device * * If a tty device is registered with a call to tty_register_device() then * this function must be called when the tty device is gone. * * Locking: ?? */ void tty_unregister_device(struct tty_driver *driver, unsigned index) { device_destroy(tty_class, MKDEV(driver->major, driver->minor_start) + index); } EXPORT_SYMBOL(tty_register_device); EXPORT_SYMBOL(tty_unregister_device); struct tty_driver *alloc_tty_driver(int lines) { struct tty_driver *driver; driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL); if (driver) { driver->magic = TTY_DRIVER_MAGIC; driver->num = lines; /* later we'll move allocation of tables here */ } return driver; } void put_tty_driver(struct tty_driver *driver) { kfree(driver); } void tty_set_operations(struct tty_driver *driver, const struct tty_operations *op) { driver->ops = op; }; EXPORT_SYMBOL(alloc_tty_driver); EXPORT_SYMBOL(put_tty_driver); EXPORT_SYMBOL(tty_set_operations); /* * Called by a tty driver to register itself. */ int tty_register_driver(struct tty_driver *driver) { int error; int i; dev_t dev; void **p = NULL; if (driver->flags & TTY_DRIVER_INSTALLED) return 0; if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM) && driver->num) { p = kzalloc(driver->num * 3 * sizeof(void *), GFP_KERNEL); if (!p) return -ENOMEM; } if (!driver->major) { error = alloc_chrdev_region(&dev, driver->minor_start, driver->num, driver->name); if (!error) { driver->major = MAJOR(dev); driver->minor_start = MINOR(dev); } } else { dev = MKDEV(driver->major, driver->minor_start); error = register_chrdev_region(dev, driver->num, driver->name); } if (error < 0) { kfree(p); return error; } if (p) { driver->ttys = (struct tty_struct **)p; driver->termios = (struct ktermios **)(p + driver->num); driver->termios_locked = (struct ktermios **) (p + driver->num * 2); } else { driver->ttys = NULL; driver->termios = NULL; driver->termios_locked = NULL; } cdev_init(&driver->cdev, &tty_fops); driver->cdev.owner = driver->owner; error = cdev_add(&driver->cdev, dev, driver->num); if (error) { unregister_chrdev_region(dev, driver->num); driver->ttys = NULL; driver->termios = driver->termios_locked = NULL; kfree(p); return error; } mutex_lock(&tty_mutex); list_add(&driver->tty_drivers, &tty_drivers); mutex_unlock(&tty_mutex); if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) { for (i = 0; i < driver->num; i++) tty_register_device(driver, i, NULL); } proc_tty_register_driver(driver); return 0; } EXPORT_SYMBOL(tty_register_driver); /* * Called by a tty driver to unregister itself. */ int tty_unregister_driver(struct tty_driver *driver) { int i; struct ktermios *tp; void *p; if (driver->refcount) return -EBUSY; unregister_chrdev_region(MKDEV(driver->major, driver->minor_start), driver->num); mutex_lock(&tty_mutex); list_del(&driver->tty_drivers); mutex_unlock(&tty_mutex); /* * 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); } tp = driver->termios_locked[i]; if (tp) { driver->termios_locked[i] = NULL; kfree(tp); } if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) tty_unregister_device(driver, i); } p = driver->ttys; proc_tty_unregister_driver(driver); driver->ttys = NULL; driver->termios = driver->termios_locked = NULL; kfree(p); cdev_del(&driver->cdev); return 0; } EXPORT_SYMBOL(tty_unregister_driver); dev_t tty_devnum(struct tty_struct *tty) { return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index; } EXPORT_SYMBOL(tty_devnum); void proc_clear_tty(struct task_struct *p) { spin_lock_irq(&p->sighand->siglock); p->signal->tty = NULL; spin_unlock_irq(&p->sighand->siglock); } /* Called under the sighand lock */ static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty) { if (tty) { unsigned long flags; /* We should not have a session or pgrp to put here but.... */ spin_lock_irqsave(&tty->ctrl_lock, flags); put_pid(tty->session); put_pid(tty->pgrp); tty->pgrp = get_pid(task_pgrp(tsk)); spin_unlock_irqrestore(&tty->ctrl_lock, flags); tty->session = get_pid(task_session(tsk)); } put_pid(tsk->signal->tty_old_pgrp); tsk->signal->tty = tty; tsk->signal->tty_old_pgrp = NULL; } static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty) { spin_lock_irq(&tsk->sighand->siglock); __proc_set_tty(tsk, tty); spin_unlock_irq(&tsk->sighand->siglock); } struct tty_struct *get_current_tty(void) { struct tty_struct *tty; WARN_ON_ONCE(!mutex_is_locked(&tty_mutex)); tty = current->signal->tty; /* * session->tty can be changed/cleared from under us, make sure we * issue the load. The obtained pointer, when not NULL, is valid as * long as we hold tty_mutex. */ barrier(); return tty; } EXPORT_SYMBOL_GPL(get_current_tty); /* * Initialize the console device. This is called *early*, so * we can't necessarily depend on lots of kernel help here. * Just do some early initializations, and do the complex setup * later. */ void __init console_init(void) { initcall_t *call; /* Setup the default TTY line discipline. */ tty_ldisc_begin(); /* * set up the console device so that later boot sequences can * inform about problems etc.. */ call = __con_initcall_start; while (call < __con_initcall_end) { (*call)(); call++; } } static int __init tty_class_init(void) { tty_class = class_create(THIS_MODULE, "tty"); if (IS_ERR(tty_class)) return PTR_ERR(tty_class); return 0; } postcore_initcall(tty_class_init); /* 3/2004 jmc: why do these devices exist? */ static struct cdev tty_cdev, console_cdev; #ifdef CONFIG_UNIX98_PTYS static struct cdev ptmx_cdev; #endif #ifdef CONFIG_VT static struct cdev vc0_cdev; #endif /* * Ok, now we can initialize the rest of the tty devices and can count * on memory allocations, interrupts etc.. */ static int __init tty_init(void) { cdev_init(&tty_cdev, &tty_fops); if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) || register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0) panic("Couldn't register /dev/tty driver\n"); device_create_drvdata(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty"); cdev_init(&console_cdev, &console_fops); if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) || register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0) panic("Couldn't register /dev/console driver\n"); device_create_drvdata(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL, "console"); #ifdef CONFIG_UNIX98_PTYS cdev_init(&ptmx_cdev, &ptmx_fops); if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) || register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0) panic("Couldn't register /dev/ptmx driver\n"); device_create_drvdata(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx"); #endif #ifdef CONFIG_VT cdev_init(&vc0_cdev, &console_fops); if (cdev_add(&vc0_cdev, MKDEV(TTY_MAJOR, 0), 1) || register_chrdev_region(MKDEV(TTY_MAJOR, 0), 1, "/dev/vc/0") < 0) panic("Couldn't register /dev/tty0 driver\n"); device_create_drvdata(tty_class, NULL, MKDEV(TTY_MAJOR, 0), NULL, "tty0"); vty_init(); #endif return 0; } module_init(tty_init);