diff options
Diffstat (limited to 'linux-2.6-xen-sparse/drivers/char/tty_io.c')
| -rw-r--r-- | linux-2.6-xen-sparse/drivers/char/tty_io.c | 3927 |
1 files changed, 0 insertions, 3927 deletions
diff --git a/linux-2.6-xen-sparse/drivers/char/tty_io.c b/linux-2.6-xen-sparse/drivers/char/tty_io.c deleted file mode 100644 index 20b4f57d44..0000000000 --- a/linux-2.6-xen-sparse/drivers/char/tty_io.c +++ /dev/null @@ -1,3927 +0,0 @@ -/* - * linux/drivers/char/tty_io.c - * - * Copyright (C) 1991, 1992 Linus Torvalds - */ - -/* - * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles - * or rs-channels. It also implements echoing, cooked mode etc. - * - * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0. - * - * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the - * tty_struct and tty_queue structures. Previously there was an array - * of 256 tty_struct's which was statically allocated, and the - * tty_queue structures were allocated at boot time. Both are now - * dynamically allocated only when the tty is open. - * - * Also restructured routines so that there is more of a separation - * between the high-level tty routines (tty_io.c and tty_ioctl.c) and - * the low-level tty routines (serial.c, pty.c, console.c). This - * makes for cleaner and more compact code. -TYT, 9/17/92 - * - * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines - * which can be dynamically activated and de-activated by the line - * discipline handling modules (like SLIP). - * - * NOTE: pay no attention to the line discipline code (yet); its - * interface is still subject to change in this version... - * -- TYT, 1/31/92 - * - * Added functionality to the OPOST tty handling. No delays, but all - * other bits should be there. - * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993. - * - * Rewrote canonical mode and added more termios flags. - * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94 - * - * Reorganized FASYNC support so mouse code can share it. - * -- ctm@ardi.com, 9Sep95 - * - * New TIOCLINUX variants added. - * -- mj@k332.feld.cvut.cz, 19-Nov-95 - * - * Restrict vt switching via ioctl() - * -- grif@cs.ucr.edu, 5-Dec-95 - * - * Move console and virtual terminal code to more appropriate files, - * implement CONFIG_VT and generalize console device interface. - * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97 - * - * Rewrote init_dev and release_dev to eliminate races. - * -- Bill Hawes <whawes@star.net>, June 97 - * - * Added devfs support. - * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998 - * - * Added support for a Unix98-style ptmx device. - * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998 - * - * Reduced memory usage for older ARM systems - * -- Russell King <rmk@arm.linux.org.uk> - * - * Move do_SAK() into process context. Less stack use in devfs functions. - * alloc_tty_struct() always uses kmalloc() -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01 - */ - -#include <linux/types.h> -#include <linux/major.h> -#include <linux/errno.h> -#include <linux/signal.h> -#include <linux/fcntl.h> -#include <linux/sched.h> -#include <linux/interrupt.h> -#include <linux/tty.h> -#include <linux/tty_driver.h> -#include <linux/tty_flip.h> -#include <linux/devpts_fs.h> -#include <linux/file.h> -#include <linux/console.h> -#include <linux/timer.h> -#include <linux/ctype.h> -#include <linux/kd.h> -#include <linux/mm.h> -#include <linux/string.h> -#include <linux/slab.h> -#include <linux/poll.h> -#include <linux/proc_fs.h> -#include <linux/init.h> -#include <linux/module.h> -#include <linux/smp_lock.h> -#include <linux/device.h> -#include <linux/idr.h> -#include <linux/wait.h> -#include <linux/bitops.h> -#include <linux/delay.h> - -#include <asm/uaccess.h> -#include <asm/system.h> - -#include <linux/kbd_kern.h> -#include <linux/vt_kern.h> -#include <linux/selection.h> - -#include <linux/kmod.h> - -#undef TTY_DEBUG_HANGUP - -#define TTY_PARANOIA_CHECK 1 -#define CHECK_TTY_COUNT 1 - -struct termios tty_std_termios = { /* for the benefit of tty drivers */ - .c_iflag = ICRNL | IXON, - .c_oflag = OPOST | ONLCR, - .c_cflag = B38400 | CS8 | CREAD | HUPCL, - .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK | - ECHOCTL | ECHOKE | IEXTEN, - .c_cc = INIT_C_CC -}; - -EXPORT_SYMBOL(tty_std_termios); - -/* This list gets poked at by procfs and various bits of boot up code. This - could do with some rationalisation such as pulling the tty proc function - into this file */ - -LIST_HEAD(tty_drivers); /* linked list of tty drivers */ - -/* Semaphore to protect creating and releasing a tty. This is shared with - vt.c for deeply disgusting hack reasons */ -DEFINE_MUTEX(tty_mutex); - -int console_use_vt = 1; - -#ifdef CONFIG_UNIX98_PTYS -extern struct tty_driver *ptm_driver; /* Unix98 pty masters; for /dev/ptmx */ -extern int pty_limit; /* Config limit on Unix98 ptys */ -static DEFINE_IDR(allocated_ptys); -static DECLARE_MUTEX(allocated_ptys_lock); -static int ptmx_open(struct inode *, struct file *); -#endif - -extern void disable_early_printk(void); - -static void initialize_tty_struct(struct tty_struct *tty); - -static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *); -static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *); -ssize_t redirected_tty_write(struct file *, const char __user *, size_t, loff_t *); -static unsigned int tty_poll(struct file *, poll_table *); -static int tty_open(struct inode *, struct file *); -static int tty_release(struct inode *, struct file *); -int tty_ioctl(struct inode * inode, struct file * file, - unsigned int cmd, unsigned long arg); -static int tty_fasync(int fd, struct file * filp, int on); -static void release_mem(struct tty_struct *tty, int idx); - -/** - * 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 - * FIXME: use kzalloc - */ - -static struct tty_struct *alloc_tty_struct(void) -{ - struct tty_struct *tty; - - tty = kmalloc(sizeof(struct tty_struct), GFP_KERNEL); - if (tty) - memset(tty, 0, sizeof(struct tty_struct)); - return tty; -} - -static void tty_buffer_free_all(struct tty_struct *); - -/** - * 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; -} - -/* - * Tty buffer allocation management - */ - - -/** - * tty_buffer_free_all - free buffers used by a tty - * @tty: tty to free from - * - * Remove all the buffers pending on a tty whether queued with data - * or in the free ring. Must be called when the tty is no longer in use - * - * Locking: none - */ - - -/** - * tty_buffer_free_all - free buffers used by a tty - * @tty: tty to free from - * - * Remove all the buffers pending on a tty whether queued with data - * or in the free ring. Must be called when the tty is no longer in use - * - * Locking: none - */ - -static void tty_buffer_free_all(struct tty_struct *tty) -{ - struct tty_buffer *thead; - while((thead = tty->buf.head) != NULL) { - tty->buf.head = thead->next; - kfree(thead); - } - while((thead = tty->buf.free) != NULL) { - tty->buf.free = thead->next; - kfree(thead); - } - tty->buf.tail = NULL; - tty->buf.memory_used = 0; -} - -/** - * tty_buffer_init - prepare a tty buffer structure - * @tty: tty to initialise - * - * Set up the initial state of the buffer management for a tty device. - * Must be called before the other tty buffer functions are used. - * - * Locking: none - */ - -static void tty_buffer_init(struct tty_struct *tty) -{ - spin_lock_init(&tty->buf.lock); - tty->buf.head = NULL; - tty->buf.tail = NULL; - tty->buf.free = NULL; - tty->buf.memory_used = 0; -} - -/** - * tty_buffer_alloc - allocate a tty buffer - * @tty: tty device - * @size: desired size (characters) - * - * Allocate a new tty buffer to hold the desired number of characters. - * Return NULL if out of memory or the allocation would exceed the - * per device queue - * - * Locking: Caller must hold tty->buf.lock - */ - -static struct tty_buffer *tty_buffer_alloc(struct tty_struct *tty, size_t size) -{ - struct tty_buffer *p; - - if (tty->buf.memory_used + size > 65536) - return NULL; - p = kmalloc(sizeof(struct tty_buffer) + 2 * size, GFP_ATOMIC); - if(p == NULL) - return NULL; - p->used = 0; - p->size = size; - p->next = NULL; - p->commit = 0; - p->read = 0; - p->char_buf_ptr = (char *)(p->data); - p->flag_buf_ptr = (unsigned char *)p->char_buf_ptr + size; - tty->buf.memory_used += size; - return p; -} - -/** - * tty_buffer_free - free a tty buffer - * @tty: tty owning the buffer - * @b: the buffer to free - * - * Free a tty buffer, or add it to the free list according to our - * internal strategy - * - * Locking: Caller must hold tty->buf.lock - */ - -static void tty_buffer_free(struct tty_struct *tty, struct tty_buffer *b) -{ - /* Dumb strategy for now - should keep some stats */ - tty->buf.memory_used -= b->size; - WARN_ON(tty->buf.memory_used < 0); - - if(b->size >= 512) - kfree(b); - else { - b->next = tty->buf.free; - tty->buf.free = b; - } -} - -/** - * tty_buffer_find - find a free tty buffer - * @tty: tty owning the buffer - * @size: characters wanted - * - * Locate an existing suitable tty buffer or if we are lacking one then - * allocate a new one. We round our buffers off in 256 character chunks - * to get better allocation behaviour. - * - * Locking: Caller must hold tty->buf.lock - */ - -static struct tty_buffer *tty_buffer_find(struct tty_struct *tty, size_t size) -{ - struct tty_buffer **tbh = &tty->buf.free; - while((*tbh) != NULL) { - struct tty_buffer *t = *tbh; - if(t->size >= size) { - *tbh = t->next; - t->next = NULL; - t->used = 0; - t->commit = 0; - t->read = 0; - tty->buf.memory_used += t->size; - return t; - } - tbh = &((*tbh)->next); - } - /* Round the buffer size out */ - size = (size + 0xFF) & ~ 0xFF; - return tty_buffer_alloc(tty, size); - /* Should possibly check if this fails for the largest buffer we - have queued and recycle that ? */ -} - -/** - * tty_buffer_request_room - grow tty buffer if needed - * @tty: tty structure - * @size: size desired - * - * Make at least size bytes of linear space available for the tty - * buffer. If we fail return the size we managed to find. - * - * Locking: Takes tty->buf.lock - */ -int tty_buffer_request_room(struct tty_struct *tty, size_t size) -{ - struct tty_buffer *b, *n; - int left; - unsigned long flags; - - spin_lock_irqsave(&tty->buf.lock, flags); - - /* OPTIMISATION: We could keep a per tty "zero" sized buffer to - remove this conditional if its worth it. This would be invisible - to the callers */ - if ((b = tty->buf.tail) != NULL) - left = b->size - b->used; - else - left = 0; - - if (left < size) { - /* This is the slow path - looking for new buffers to use */ - if ((n = tty_buffer_find(tty, size)) != NULL) { - if (b != NULL) { - b->next = n; - b->commit = b->used; - } else - tty->buf.head = n; - tty->buf.tail = n; - } else - size = left; - } - - spin_unlock_irqrestore(&tty->buf.lock, flags); - return size; -} -EXPORT_SYMBOL_GPL(tty_buffer_request_room); - -/** - * tty_insert_flip_string - Add characters to the tty buffer - * @tty: tty structure - * @chars: characters - * @size: size - * - * Queue a series of bytes to the tty buffering. All the characters - * passed are marked as without error. Returns the number added. - * - * Locking: Called functions may take tty->buf.lock - */ - -int tty_insert_flip_string(struct tty_struct *tty, const unsigned char *chars, - size_t size) -{ - int copied = 0; - do { - int space = tty_buffer_request_room(tty, size - copied); - struct tty_buffer *tb = tty->buf.tail; - /* If there is no space then tb may be NULL */ - if(unlikely(space == 0)) - break; - memcpy(tb->char_buf_ptr + tb->used, chars, space); - memset(tb->flag_buf_ptr + tb->used, TTY_NORMAL, space); - tb->used += space; - copied += space; - chars += space; - } - /* There is a small chance that we need to split the data over - several buffers. If this is the case we must loop */ - while (unlikely(size > copied)); - return copied; -} -EXPORT_SYMBOL(tty_insert_flip_string); - -/** - * tty_insert_flip_string_flags - Add characters to the tty buffer - * @tty: tty structure - * @chars: characters - * @flags: flag bytes - * @size: size - * - * Queue a series of bytes to the tty buffering. For each character - * the flags array indicates the status of the character. Returns the - * number added. - * - * Locking: Called functions may take tty->buf.lock - */ - -int tty_insert_flip_string_flags(struct tty_struct *tty, - const unsigned char *chars, const char *flags, size_t size) -{ - int copied = 0; - do { - int space = tty_buffer_request_room(tty, size - copied); - struct tty_buffer *tb = tty->buf.tail; - /* If there is no space then tb may be NULL */ - if(unlikely(space == 0)) - break; - memcpy(tb->char_buf_ptr + tb->used, chars, space); - memcpy(tb->flag_buf_ptr + tb->used, flags, space); - tb->used += space; - copied += space; - chars += space; - flags += space; - } - /* There is a small chance that we need to split the data over - several buffers. If this is the case we must loop */ - while (unlikely(size > copied)); - return copied; -} -EXPORT_SYMBOL(tty_insert_flip_string_flags); - -/** - * tty_schedule_flip - push characters to ldisc - * @tty: tty to push from - * - * Takes any pending buffers and transfers their ownership to the - * ldisc side of the queue. It then schedules those characters for - * processing by the line discipline. - * - * Locking: Takes tty->buf.lock - */ - -void tty_schedule_flip(struct tty_struct *tty) -{ - unsigned long flags; - spin_lock_irqsave(&tty->buf.lock, flags); - if (tty->buf.tail != NULL) - tty->buf.tail->commit = tty->buf.tail->used; - spin_unlock_irqrestore(&tty->buf.lock, flags); - schedule_delayed_work(&tty->buf.work, 1); -} -EXPORT_SYMBOL(tty_schedule_flip); - -/** - * tty_prepare_flip_string - make room for characters - * @tty: tty - * @chars: return pointer for character write area - * @size: desired size - * - * Prepare a block of space in the buffer for data. Returns the length - * available and buffer pointer to the space which is now allocated and - * accounted for as ready for normal characters. This is used for drivers - * that need their own block copy routines into the buffer. There is no - * guarantee the buffer is a DMA target! - * - * Locking: May call functions taking tty->buf.lock - */ - -int tty_prepare_flip_string(struct tty_struct *tty, unsigned char **chars, size_t size) -{ - int space = tty_buffer_request_room(tty, size); - if (likely(space)) { - struct tty_buffer *tb = tty->buf.tail; - *chars = tb->char_buf_ptr + tb->used; - memset(tb->flag_buf_ptr + tb->used, TTY_NORMAL, space); - tb->used += space; - } - return space; -} - -EXPORT_SYMBOL_GPL(tty_prepare_flip_string); - -/** - * tty_prepare_flip_string_flags - make room for characters - * @tty: tty - * @chars: return pointer for character write area - * @flags: return pointer for status flag write area - * @size: desired size - * - * Prepare a block of space in the buffer for data. Returns the length - * available and buffer pointer to the space which is now allocated and - * accounted for as ready for characters. This is used for drivers - * that need their own block copy routines into the buffer. There is no - * guarantee the buffer is a DMA target! - * - * Locking: May call functions taking tty->buf.lock - */ - -int tty_prepare_flip_string_flags(struct tty_struct *tty, unsigned char **chars, char **flags, size_t size) -{ - int space = tty_buffer_request_room(tty, size); - if (likely(space)) { - struct tty_buffer *tb = tty->buf.tail; - *chars = tb->char_buf_ptr + tb->used; - *flags = tb->flag_buf_ptr + tb->used; - tb->used += space; - } - return space; -} - -EXPORT_SYMBOL_GPL(tty_prepare_flip_string_flags); - - - -/** - * tty_set_termios_ldisc - set ldisc field - * @tty: tty structure - * @num: line discipline number - * - * This is probably overkill for real world processors but - * they are not on hot paths so a little discipline won't do - * any harm. - * - * Locking: takes termios_sem - */ - -static void tty_set_termios_ldisc(struct tty_struct *tty, int num) -{ - down(&tty->termios_sem); - tty->termios->c_line = num; - up(&tty->termios_sem); -} - -/* - * This guards the refcounted line discipline lists. The lock - * must be taken with irqs off because there are hangup path - * callers who will do ldisc lookups and cannot sleep. - */ - -static DEFINE_SPINLOCK(tty_ldisc_lock); -static DECLARE_WAIT_QUEUE_HEAD(tty_ldisc_wait); -static struct tty_ldisc tty_ldiscs[NR_LDISCS]; /* line disc dispatch table */ - -/** - * tty_register_ldisc - install a line discipline - * @disc: ldisc number - * @new_ldisc: pointer to the ldisc object - * - * Installs a new line discipline into the kernel. The discipline - * is set up as unreferenced and then made available to the kernel - * from this point onwards. - * - * Locking: - * takes tty_ldisc_lock to guard against ldisc races - */ - -int tty_register_ldisc(int disc, struct tty_ldisc *new_ldisc) -{ - unsigned long flags; - int ret = 0; - - if (disc < N_TTY || disc >= NR_LDISCS) - return -EINVAL; - - spin_lock_irqsave(&tty_ldisc_lock, flags); - tty_ldiscs[disc] = *new_ldisc; - tty_ldiscs[disc].num = disc; - tty_ldiscs[disc].flags |= LDISC_FLAG_DEFINED; - tty_ldiscs[disc].refcount = 0; - spin_unlock_irqrestore(&tty_ldisc_lock, flags); - - return ret; -} -EXPORT_SYMBOL(tty_register_ldisc); - -/** - * tty_unregister_ldisc - unload a line discipline - * @disc: ldisc number - * @new_ldisc: pointer to the ldisc object - * - * Remove a line discipline from the kernel providing it is not - * currently in use. - * - * Locking: - * takes tty_ldisc_lock to guard against ldisc races - */ - -int tty_unregister_ldisc(int disc) -{ - unsigned long flags; - int ret = 0; - - if (disc < N_TTY || disc >= NR_LDISCS) - return -EINVAL; - - spin_lock_irqsave(&tty_ldisc_lock, flags); - if (tty_ldiscs[disc].refcount) - ret = -EBUSY; - else - tty_ldiscs[disc].flags &= ~LDISC_FLAG_DEFINED; - spin_unlock_irqrestore(&tty_ldisc_lock, flags); - - return ret; -} -EXPORT_SYMBOL(tty_unregister_ldisc); - -/** - * tty_ldisc_get - take a reference to an ldisc - * @disc: ldisc number - * - * Takes a reference to a line discipline. Deals with refcounts and - * module locking counts. Returns NULL if the discipline is not available. - * Returns a pointer to the discipline and bumps the ref count if it is - * available - * - * Locking: - * takes tty_ldisc_lock to guard against ldisc races - */ - -struct tty_ldisc *tty_ldisc_get(int disc) -{ - unsigned long flags; - struct tty_ldisc *ld; - - if (disc < N_TTY || disc >= NR_LDISCS) - return NULL; - - spin_lock_irqsave(&tty_ldisc_lock, flags); - - ld = &tty_ldiscs[disc]; - /* Check the entry is defined */ - if(ld->flags & LDISC_FLAG_DEFINED) - { - /* If the module is being unloaded we can't use it */ - if (!try_module_get(ld->owner)) - ld = NULL; - else /* lock it */ - ld->refcount++; - } - else - ld = NULL; - spin_unlock_irqrestore(&tty_ldisc_lock, flags); - return ld; -} - -EXPORT_SYMBOL_GPL(tty_ldisc_get); - -/** - * tty_ldisc_put - drop ldisc reference - * @disc: ldisc number - * - * Drop a reference to a line discipline. Manage refcounts and - * module usage counts - * - * Locking: - * takes tty_ldisc_lock to guard against ldisc races - */ - -void tty_ldisc_put(int disc) -{ - struct tty_ldisc *ld; - unsigned long flags; - - BUG_ON(disc < N_TTY || disc >= NR_LDISCS); - - spin_lock_irqsave(&tty_ldisc_lock, flags); - ld = &tty_ldiscs[disc]; - BUG_ON(ld->refcount == 0); - ld->refcount--; - module_put(ld->owner); - spin_unlock_irqrestore(&tty_ldisc_lock, flags); -} - -EXPORT_SYMBOL_GPL(tty_ldisc_put); - -/** - * tty_ldisc_assign - set ldisc on a tty - * @tty: tty to assign - * @ld: line discipline - * - * Install an instance of a line discipline into a tty structure. The - * ldisc must have a reference count above zero to ensure it remains/ - * The tty instance refcount starts at zero. - * - * Locking: - * Caller must hold references - */ - -static void tty_ldisc_assign(struct tty_struct *tty, struct tty_ldisc *ld) -{ - tty->ldisc = *ld; - tty->ldisc.refcount = 0; -} - -/** - * tty_ldisc_try - internal helper - * @tty: the tty - * - * Make a single attempt to grab and bump the refcount on - * the tty ldisc. Return 0 on failure or 1 on success. This is - * used to implement both the waiting and non waiting versions - * of tty_ldisc_ref - * - * Locking: takes tty_ldisc_lock - */ - -static int tty_ldisc_try(struct tty_struct *tty) -{ - unsigned long flags; - struct tty_ldisc *ld; - int ret = 0; - - spin_lock_irqsave(&tty_ldisc_lock, flags); - ld = &tty->ldisc; - if(test_bit(TTY_LDISC, &tty->flags)) - { - ld->refcount++; - ret = 1; - } - spin_unlock_irqrestore(&tty_ldisc_lock, flags); - return ret; -} - -/** - * tty_ldisc_ref_wait - wait for the tty ldisc - * @tty: tty device - * - * Dereference the line discipline for the terminal and take a - * reference to it. If the line discipline is in flux then - * wait patiently until it changes. - * - * Note: Must not be called from an IRQ/timer context. The caller - * must also be careful not to hold other locks that will deadlock - * against a discipline change, such as an existing ldisc reference - * (which we check for) - * - * Locking: call functions take tty_ldisc_lock - */ - -struct tty_ldisc *tty_ldisc_ref_wait(struct tty_struct *tty) -{ - /* wait_event is a macro */ - wait_event(tty_ldisc_wait, tty_ldisc_try(tty)); - if(tty->ldisc.refcount == 0) - printk(KERN_ERR "tty_ldisc_ref_wait\n"); - return &tty->ldisc; -} - -EXPORT_SYMBOL_GPL(tty_ldisc_ref_wait); - -/** - * tty_ldisc_ref - get the tty ldisc - * @tty: tty device - * - * Dereference the line discipline for the terminal and take a - * reference to it. If the line discipline is in flux then - * return NULL. Can be called from IRQ and timer functions. - * - * Locking: called functions take tty_ldisc_lock - */ - -struct tty_ldisc *tty_ldisc_ref(struct tty_struct *tty) -{ - if(tty_ldisc_try(tty)) - return &tty->ldisc; - return NULL; -} - -EXPORT_SYMBOL_GPL(tty_ldisc_ref); - -/** - * tty_ldisc_deref - free a tty ldisc reference - * @ld: reference to free up - * - * Undoes the effect of tty_ldisc_ref or tty_ldisc_ref_wait. May - * be called in IRQ context. - * - * Locking: takes tty_ldisc_lock - */ - -void tty_ldisc_deref(struct tty_ldisc *ld) -{ - unsigned long flags; - - BUG_ON(ld == NULL); - - spin_lock_irqsave(&tty_ldisc_lock, flags); - if(ld->refcount == 0) - printk(KERN_ERR "tty_ldisc_deref: no references.\n"); - else - ld->refcount--; - if(ld->refcount == 0) - wake_up(&tty_ldisc_wait); - spin_unlock_irqrestore(&tty_ldisc_lock, flags); -} - -EXPORT_SYMBOL_GPL(tty_ldisc_deref); - -/** - * tty_ldisc_enable - allow ldisc use - * @tty: terminal to activate ldisc on - * - * Set the TTY_LDISC flag when the line discipline can be called - * again. Do neccessary wakeups for existing sleepers. - * - * Note: nobody should set this bit except via this function. Clearing - * directly is allowed. - */ - -static void tty_ldisc_enable(struct tty_struct *tty) -{ - set_bit(TTY_LDISC, &tty->flags); - wake_up(&tty_ldisc_wait); -} - -/** - * tty_set_ldisc - set line discipline - * @tty: the terminal to set - * @ldisc: the line discipline - * - * Set the discipline of a tty line. Must be called from a process - * context. - * - * Locking: takes tty_ldisc_lock. - * called functions take termios_sem - */ - -static int tty_set_ldisc(struct tty_struct *tty, int ldisc) -{ - int retval = 0; - struct tty_ldisc o_ldisc; - char buf[64]; - int work; - unsigned long flags; - struct tty_ldisc *ld; - struct tty_struct *o_tty; - - if ((ldisc < N_TTY) || (ldisc >= NR_LDISCS)) - return -EINVAL; - -restart: - - ld = tty_ldisc_get(ldisc); - /* Eduardo Blanco <ejbs@cs.cs.com.uy> */ - /* Cyrus Durgin <cider@speakeasy.org> */ - if (ld == NULL) { - request_module("tty-ldisc-%d", ldisc); - ld = tty_ldisc_get(ldisc); - } - if (ld == NULL) - return -EINVAL; - - /* - * No more input please, we are switching. The new ldisc - * will update this value in the ldisc open function - */ - - tty->receive_room = 0; - - /* - * Problem: What do we do if this blocks ? - */ - - tty_wait_until_sent(tty, 0); - - if (tty->ldisc.num == ldisc) { - tty_ldisc_put(ldisc); - return 0; - } - - o_ldisc = tty->ldisc; - o_tty = tty->link; - - /* - * Make sure we don't change while someone holds a - * reference to the line discipline. The TTY_LDISC bit - * prevents anyone taking a reference once it is clear. - * We need the lock to avoid racing reference takers. - */ - - spin_lock_irqsave(&tty_ldisc_lock, flags); - if (tty->ldisc.refcount || (o_tty && o_tty->ldisc.refcount)) { - if(tty->ldisc.refcount) { - /* Free the new ldisc we grabbed. Must drop the lock - first. */ - spin_unlock_irqrestore(&tty_ldisc_lock, flags); - tty_ldisc_put(ldisc); - /* - * There are several reasons we may be busy, including - * random momentary I/O traffic. We must therefore - * retry. We could distinguish between blocking ops - * and retries if we made tty_ldisc_wait() smarter. That - * is up for discussion. - */ - if (wait_event_interruptible(tty_ldisc_wait, tty->ldisc.refcount == 0) < 0) - return -ERESTARTSYS; - goto restart; - } - if(o_tty && o_tty->ldisc.refcount) { - spin_unlock_irqrestore(&tty_ldisc_lock, flags); - tty_ldisc_put(ldisc); - if (wait_event_interruptible(tty_ldisc_wait, o_tty->ldisc.refcount == 0) < 0) - return -ERESTARTSYS; - goto restart; - } - } - - /* if the TTY_LDISC bit is set, then we are racing against another ldisc change */ - - if (!test_bit(TTY_LDISC, &tty->flags)) { - spin_unlock_irqrestore(&tty_ldisc_lock, flags); - tty_ldisc_put(ldisc); - ld = tty_ldisc_ref_wait(tty); - tty_ldisc_deref(ld); - goto restart; - } - - clear_bit(TTY_LDISC, &tty->flags); - if (o_tty) - clear_bit(TTY_LDISC, &o_tty->flags); - spin_unlock_irqrestore(&tty_ldisc_lock, flags); - - /* - * From this point on we know nobody has an ldisc - * usage reference, nor can they obtain one until - * we say so later on. - */ - - work = cancel_delayed_work(&tty->buf.work); - /* - * Wait for ->hangup_work and ->buf.work handlers to terminate - */ - - flush_scheduled_work(); - /* Shutdown the current discipline. */ - if (tty->ldisc.close) - (tty->ldisc.close)(tty); - - /* Now set up the new line discipline. */ - tty_ldisc_assign(tty, ld); - tty_set_termios_ldisc(tty, ldisc); - if (tty->ldisc.open) - retval = (tty->ldisc.open)(tty); - if (retval < 0) { - tty_ldisc_put(ldisc); - /* There is an outstanding reference here so this is safe */ - tty_ldisc_assign(tty, tty_ldisc_get(o_ldisc.num)); - tty_set_termios_ldisc(tty, tty->ldisc.num); - if (tty->ldisc.open && (tty->ldisc.open(tty) < 0)) { - tty_ldisc_put(o_ldisc.num); - /* This driver is always present */ - tty_ldisc_assign(tty, tty_ldisc_get(N_TTY)); - tty_set_termios_ldisc(tty, N_TTY); - if (tty->ldisc.open) { - int r = tty->ldisc.open(tty); - - if (r < 0) - panic("Couldn't open N_TTY ldisc for " - "%s --- error %d.", - tty_name(tty, buf), r); - } - } - } - /* At this point we hold a reference to the new ldisc and a - a reference to the old ldisc. If we ended up flipping back - to the existing ldisc we have two references to it */ - - if (tty->ldisc.num != o_ldisc.num && tty->driver->set_ldisc) - tty->driver->set_ldisc(tty); - - tty_ldisc_put(o_ldisc.num); - - /* - * Allow ldisc referencing to occur as soon as the driver - * ldisc callback completes. - */ - - tty_ldisc_enable(tty); - if (o_tty) - tty_ldisc_enable(o_tty); - - /* Restart it in case no characters kick it off. Safe if - already running */ - if (work) - schedule_delayed_work(&tty->buf.work, 1); - return retval; -} - -/** - * 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; -} - -/** - * 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: none - */ - -int tty_check_change(struct tty_struct * tty) -{ - if (current->signal->tty != tty) - return 0; - if (tty->pgrp <= 0) { - printk(KERN_WARNING "tty_check_change: tty->pgrp <= 0!\n"); - return 0; - } - if (process_group(current) == tty->pgrp) - return 0; - if (is_ignored(SIGTTOU)) - return 0; - if (is_orphaned_pgrp(process_group(current))) - return -EIO; - (void) kill_pg(process_group(current), SIGTTOU, 1); - return -ERESTARTSYS; -} - -EXPORT_SYMBOL(tty_check_change); - -static ssize_t hung_up_tty_read(struct file * file, char __user * buf, - size_t count, loff_t *ppos) -{ - return 0; -} - -static ssize_t hung_up_tty_write(struct file * file, const char __user * buf, - size_t count, loff_t *ppos) -{ - return -EIO; -} - -/* No kernel lock held - none needed ;) */ -static unsigned int hung_up_tty_poll(struct file * filp, poll_table * wait) -{ - return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM; -} - -static int hung_up_tty_ioctl(struct inode * inode, struct file * file, - unsigned int cmd, unsigned long arg) -{ - return cmd == TIOCSPGRP ? -ENOTTY : -EIO; -} - -static const struct file_operations tty_fops = { - .llseek = no_llseek, - .read = tty_read, - .write = tty_write, - .poll = tty_poll, - .ioctl = tty_ioctl, - .open = tty_open, - .release = tty_release, - .fasync = tty_fasync, -}; - -#ifdef CONFIG_UNIX98_PTYS -static const struct file_operations ptmx_fops = { - .llseek = no_llseek, - .read = tty_read, - .write = tty_write, - .poll = tty_poll, - .ioctl = tty_ioctl, - .open = ptmx_open, - .release = tty_release, - .fasync = tty_fasync, -}; -#endif - -static const struct file_operations console_fops = { - .llseek = no_llseek, - .read = tty_read, - .write = redirected_tty_write, - .poll = tty_poll, - .ioctl = tty_ioctl, - .open = tty_open, - .release = tty_release, - .fasync = tty_fasync, -}; - -static 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, - .ioctl = hung_up_tty_ioctl, - .release = tty_release, -}; - -static DEFINE_SPINLOCK(redirect_lock); -static struct file *redirect; - -/** - * tty_wakeup - request more data - * @tty: terminal - * - * Internal and external helper for wakeups of tty. This function - * informs the line discipline if present that the driver is ready - * to receive more output data. - */ - -void tty_wakeup(struct tty_struct *tty) -{ - struct tty_ldisc *ld; - - if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) { - ld = tty_ldisc_ref(tty); - if(ld) { - if(ld->write_wakeup) - ld->write_wakeup(tty); - tty_ldisc_deref(ld); - } - } - wake_up_interruptible(&tty->write_wait); -} - -EXPORT_SYMBOL_GPL(tty_wakeup); - -/** - * tty_ldisc_flush - flush line discipline queue - * @tty: tty - * - * Flush the line discipline queue (if any) for this tty. If there - * is no line discipline active this is a no-op. - */ - -void tty_ldisc_flush(struct tty_struct *tty) -{ - struct tty_ldisc *ld = tty_ldisc_ref(tty); - if(ld) { - if(ld->flush_buffer) - ld->flush_buffer(tty); - tty_ldisc_deref(ld); - } -} - -EXPORT_SYMBOL_GPL(tty_ldisc_flush); - -/** - * do_tty_hangup - actual handler for hangup events - * @data: 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_sem resetting termios data - * tasklist_lock to walk task list for hangup event - * - */ -static void do_tty_hangup(void *data) -{ - struct tty_struct *tty = (struct tty_struct *) data; - struct file * cons_filp = NULL; - struct file *filp, *f = NULL; - struct task_struct *p; - struct tty_ldisc *ld; - int closecount = 0, n; - - if (!tty) - return; - - /* inuse_filps is protected by the single kernel lock */ - lock_kernel(); - - spin_lock(&redirect_lock); - if (redirect && redirect->private_data == tty) { - f = redirect; - redirect = NULL; - } - spin_unlock(&redirect_lock); - - check_tty_count(tty, "do_tty_hangup"); - file_list_lock(); - /* This breaks for file handles being sent over AF_UNIX sockets ? */ - list_for_each_entry(filp, &tty->tty_files, f_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->flush_buffer) - ld->flush_buffer(tty); - if (tty->driver->flush_buffer) - tty->driver->flush_buffer(tty); - if ((test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) && - ld->write_wakeup) - ld->write_wakeup(tty); - if (ld->hangup) - ld->hangup(tty); - } - - /* FIXME: Once we trust the LDISC code better we can wait here for - ldisc completion and fix the driver call race */ - - wake_up_interruptible(&tty->write_wait); - wake_up_interruptible(&tty->read_wait); - - /* - * Shutdown the current line discipline, and reset it to - * N_TTY. - */ - if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) - { - down(&tty->termios_sem); - *tty->termios = tty->driver->init_termios; - up(&tty->termios_sem); - } - - /* Defer ldisc switch */ - /* tty_deferred_ldisc_switch(N_TTY); - - This should get done automatically when the port closes and - tty_release is called */ - - read_lock(&tasklist_lock); - if (tty->session > 0) { - do_each_task_pid(tty->session, PIDTYPE_SID, p) { - if (p->signal->tty == tty) - p->signal->tty = NULL; - if (!p->signal->leader) - continue; - group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p); - group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p); - if (tty->pgrp > 0) - p->signal->tty_old_pgrp = tty->pgrp; - } while_each_task_pid(tty->session, PIDTYPE_SID, p); - } - read_unlock(&tasklist_lock); - - tty->flags = 0; - tty->session = 0; - tty->pgrp = -1; - tty->ctrl_status = 0; - /* - * If one of the devices matches a console pointer, we - * cannot just call hangup() because that will cause - * tty->count and state->count to go out of sync. - * So we just call close() the right number of times. - */ - if (cons_filp) { - if (tty->driver->close) - for (n = 0; n < closecount; n++) - tty->driver->close(tty, cons_filp); - } else if (tty->driver->hangup) - (tty->driver->hangup)(tty); - - /* We don't want to have driver/ldisc interactions beyond - the ones we did here. The driver layer expects no - calls after ->hangup() from the ldisc side. However we - can't yet guarantee all that */ - - set_bit(TTY_HUPPED, &tty->flags); - if (ld) { - tty_ldisc_enable(tty); - tty_ldisc_deref(ld); - } - unlock_kernel(); - if (f) - fput(f); -} - -/** - * 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 neccessary 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((void *) tty); -} -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); - -/** - * 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: tty_mutex is taken to protect current->signal->tty - * BKL is taken for hysterical raisins - * Tasklist lock is taken (under tty_mutex) to walk process - * lists for the session. - */ - -void disassociate_ctty(int on_exit) -{ - struct tty_struct *tty; - struct task_struct *p; - int tty_pgrp = -1; - - lock_kernel(); - - mutex_lock(&tty_mutex); - tty = current->signal->tty; - if (tty) { - tty_pgrp = tty->pgrp; - mutex_unlock(&tty_mutex); - if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY) - tty_vhangup(tty); - } else { - if (current->signal->tty_old_pgrp) { - kill_pg(current->signal->tty_old_pgrp, SIGHUP, on_exit); - kill_pg(current->signal->tty_old_pgrp, SIGCONT, on_exit); - } - mutex_unlock(&tty_mutex); - unlock_kernel(); - return; - } - if (tty_pgrp > 0) { - kill_pg(tty_pgrp, SIGHUP, on_exit); - if (!on_exit) - kill_pg(tty_pgrp, SIGCONT, on_exit); - } - - /* Must lock changes to tty_old_pgrp */ - mutex_lock(&tty_mutex); - current->signal->tty_old_pgrp = 0; - tty->session = 0; - tty->pgrp = -1; - - /* Now clear signal->tty under the lock */ - read_lock(&tasklist_lock); - do_each_task_pid(current->signal->session, PIDTYPE_SID, p) { - p->signal->tty = NULL; - } while_each_task_pid(current->signal->session, PIDTYPE_SID, p); - read_unlock(&tasklist_lock); - mutex_unlock(&tty_mutex); - unlock_kernel(); -} - - -/** - * stop_tty - propogate flow control - * @tty: tty to stop - * - * Perform flow control to the driver. For PTY/TTY pairs we - * must also propogate 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: - * Broken. Relies on BKL which is unsafe here. - */ - -void stop_tty(struct tty_struct *tty) -{ - if (tty->stopped) - return; - tty->stopped = 1; - if (tty->link && tty->link->packet) { - tty->ctrl_status &= ~TIOCPKT_START; - tty->ctrl_status |= TIOCPKT_STOP; - wake_up_interruptible(&tty->link->read_wait); - } - if (tty->driver->stop) - (tty->driver->stop)(tty); -} - -EXPORT_SYMBOL(stop_tty); - -/** - * start_tty - propogate flow control - * @tty: tty to start - * - * Start a tty that has been stopped if at all possible. Perform - * any neccessary wakeups and propogate 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: - * Broken. Relies on BKL which is unsafe here. - */ - -void start_tty(struct tty_struct *tty) -{ - if (!tty->stopped || tty->flow_stopped) - return; - tty->stopped = 0; - if (tty->link && tty->link->packet) { - tty->ctrl_status &= ~TIOCPKT_STOP; - tty->ctrl_status |= TIOCPKT_START; - wake_up_interruptible(&tty->link->read_wait); - } - if (tty->driver->start) - (tty->driver->start)(tty); - - /* If we have a running line discipline it may need kicking */ - tty_wakeup(tty); - wake_up_interruptible(&tty->write_wait); -} - -EXPORT_SYMBOL(start_tty); - -/** - * 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 - * For historical reasons the line discipline read method is - * invoked under the BKL. This will go away in time so do not rely on it - * in new code. 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_dentry->d_inode; - if (tty_paranoia_check(tty, inode, "tty_read")) - return -EIO; - if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags))) - return -EIO; - - /* We want to wait for the line discipline to sort out in this - situation */ - ld = tty_ldisc_ref_wait(tty); - lock_kernel(); - if (ld->read) - i = (ld->read)(tty,file,buf,count); - else - i = -EIO; - tty_ldisc_deref(ld); - unlock_kernel(); - if (i > 0) - inode->i_atime = current_fs_time(inode->i_sb); - return i; -} - -/* - * Split writes up in sane blocksizes to avoid - * denial-of-service type attacks - */ -static inline ssize_t do_tty_write( - ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t), - struct tty_struct *tty, - struct file *file, - const char __user *buf, - size_t count) -{ - ssize_t ret = 0, written = 0; - unsigned int chunk; - - /* FIXME: O_NDELAY ... */ - if (mutex_lock_interruptible(&tty->atomic_write_lock)) { - return -ERESTARTSYS; - } - - /* - * We chunk up writes into a temporary buffer. This - * simplifies low-level drivers immensely, since they - * don't have locking issues and user mode accesses. - * - * But if TTY_NO_WRITE_SPLIT is set, we should use a - * big chunk-size.. - * - * The default chunk-size is 2kB, because the NTTY - * layer has problems with bigger chunks. It will - * claim to be able to handle more characters than - * it actually does. - * - * 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) { - mutex_unlock(&tty->atomic_write_lock); - return -ENOMEM; - } - kfree(tty->write_buf); - tty->write_cnt = chunk; - tty->write_buf = buf; - } - - /* Do the write .. */ - for (;;) { - size_t size = count; - if (size > chunk) - size = chunk; - ret = -EFAULT; - if (copy_from_user(tty->write_buf, buf, size)) - break; - lock_kernel(); - ret = write(tty, file, tty->write_buf, size); - unlock_kernel(); - if (ret <= 0) - break; - written += ret; - buf += ret; - count -= ret; - if (!count) - break; - ret = -ERESTARTSYS; - if (signal_pending(current)) - break; - cond_resched(); - } - if (written) { - struct inode *inode = file->f_dentry->d_inode; - inode->i_mtime = current_fs_time(inode->i_sb); - ret = written; - } - mutex_unlock(&tty->atomic_write_lock); - 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_dentry->d_inode; - ssize_t ret; - struct tty_ldisc *ld; - - tty = (struct tty_struct *)file->private_data; - if (tty_paranoia_check(tty, inode, "tty_write")) - return -EIO; - if (!tty || !tty->driver->write || (test_bit(TTY_IO_ERROR, &tty->flags))) - return -EIO; - - ld = tty_ldisc_ref_wait(tty); - if (!ld->write) - ret = -EIO; - else - ret = do_tty_write(ld->write, tty, file, buf, count); - tty_ldisc_deref(ld); - return ret; -} - -ssize_t redirected_tty_write(struct file * file, const char __user * buf, size_t count, - loff_t *ppos) -{ - struct file *p = NULL; - - spin_lock(&redirect_lock); - if (redirect) { - get_file(redirect); - p = redirect; - } - spin_unlock(&redirect_lock); - - if (p) { - ssize_t res; - res = vfs_write(p, buf, count, &p->f_pos); - fput(p); - return res; - } - - return tty_write(file, buf, count, ppos); -} - -static char ptychar[] = "pqrstuvwxyzabcde"; - -/** - * 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 termios *tp, **tp_loc, *o_tp, **o_tp_loc; - struct termios *ltp, **ltp_loc, *o_ltp, **o_ltp_loc; - int retval = 0; - - /* check whether we're reopening an existing tty */ - if (driver->flags & TTY_DRIVER_DEVPTS_MEM) { - tty = devpts_get_tty(idx); - if (tty && driver->subtype == PTY_TYPE_MASTER) - tty = tty->link; - } else { - tty = driver->ttys[idx]; - } - if (tty) goto fast_track; - - /* - * First time open is complex, especially for PTY devices. - * This code guarantees that either everything succeeds and the - * TTY is ready for operation, or else the table slots are vacated - * and the allocated memory released. (Except that the termios - * and locked termios may be retained.) - */ - - if (!try_module_get(driver->owner)) { - retval = -ENODEV; - goto end_init; - } - - 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->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 = (struct termios *) kmalloc(sizeof(struct termios), - GFP_KERNEL); - if (!tp) - goto free_mem_out; - *tp = driver->init_termios; - } - - if (!*ltp_loc) { - ltp = (struct termios *) kmalloc(sizeof(struct termios), - GFP_KERNEL); - if (!ltp) - goto free_mem_out; - memset(ltp, 0, sizeof(struct termios)); - } - - 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->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 = (struct termios *) - kmalloc(sizeof(struct termios), GFP_KERNEL); - if (!o_tp) - goto free_mem_out; - *o_tp = driver->other->init_termios; - } - - if (!*o_ltp_loc) { - o_ltp = (struct termios *) - kmalloc(sizeof(struct termios), GFP_KERNEL); - if (!o_ltp) - goto free_mem_out; - memset(o_ltp, 0, sizeof(struct termios)); - } - - /* - * 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_mem 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; - driver->refcount++; - tty->count++; - - /* - * Structures all installed ... call the ldisc open routines. - * If we fail here just call release_mem to clean up. No need - * to decrement the use counts, as release_mem doesn't care. - */ - - if (tty->ldisc.open) { - retval = (tty->ldisc.open)(tty); - if (retval) - goto release_mem_out; - } - if (o_tty && o_tty->ldisc.open) { - retval = (o_tty->ldisc.open)(o_tty); - if (retval) { - if (tty->ldisc.close) - (tty->ldisc.close)(tty); - goto release_mem_out; - } - tty_ldisc_enable(o_tty); - } - tty_ldisc_enable(tty); - 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_mem routine to clean out this slot */ -release_mem_out: - printk(KERN_INFO "init_dev: ldisc open failed, " - "clearing slot %d\n", idx); - release_mem(tty, idx); - goto end_init; -} - -/** - * release_mem - 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_mem(struct tty_struct *tty, int idx) -{ - struct tty_struct *o_tty; - struct termios *tp; - int devpts = tty->driver->flags & TTY_DRIVER_DEVPTS_MEM; - - if ((o_tty = tty->link) != NULL) { - if (!devpts) - o_tty->driver->ttys[idx] = NULL; - if (o_tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) { - tp = o_tty->termios; - if (!devpts) - o_tty->driver->termios[idx] = NULL; - kfree(tp); - - tp = o_tty->termios_locked; - if (!devpts) - o_tty->driver->termios_locked[idx] = NULL; - kfree(tp); - } - o_tty->magic = 0; - o_tty->driver->refcount--; - file_list_lock(); - list_del_init(&o_tty->tty_files); - file_list_unlock(); - free_tty_struct(o_tty); - } - - 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(); - module_put(tty->driver->owner); - free_tty_struct(tty); -} - -/* - * Even releasing the tty structures is a tricky business.. We have - * to be very careful that the structures are all released at the - * same time, as interrupts might otherwise get the wrong pointers. - * - * WSH 09/09/97: rewritten to avoid some nasty race conditions that could - * lead to double frees or releasing memory still in use. - */ -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]; - unsigned long flags; - - tty = (struct tty_struct *)filp->private_data; - if (tty_paranoia_check(tty, filp->f_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->driver->close) - tty->driver->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) { - struct task_struct *p; - - read_lock(&tasklist_lock); - do_each_task_pid(tty->session, PIDTYPE_SID, p) { - p->signal->tty = NULL; - } while_each_task_pid(tty->session, PIDTYPE_SID, p); - if (o_tty) - do_each_task_pid(o_tty->session, PIDTYPE_SID, p) { - p->signal->tty = NULL; - } while_each_task_pid(o_tty->session, PIDTYPE_SID, p); - 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 - /* - * Prevent flush_to_ldisc() from rescheduling the work for later. Then - * kill any delayed work. As this is the final close it does not - * race with the set_ldisc code path. - */ - clear_bit(TTY_LDISC, &tty->flags); - cancel_delayed_work(&tty->buf.work); - - /* - * Wait for ->hangup_work and ->buf.work handlers to terminate - */ - - flush_scheduled_work(); - - /* - * Wait for any short term users (we know they are just driver - * side waiters as the file is closing so user count on the file - * side is zero. - */ - spin_lock_irqsave(&tty_ldisc_lock, flags); - while(tty->ldisc.refcount) - { - spin_unlock_irqrestore(&tty_ldisc_lock, flags); - wait_event(tty_ldisc_wait, tty->ldisc.refcount == 0); - spin_lock_irqsave(&tty_ldisc_lock, flags); - } - spin_unlock_irqrestore(&tty_ldisc_lock, flags); - /* - * Shutdown the current line discipline, and reset it to N_TTY. - * N.B. why reset ldisc when we're releasing the memory?? - * - * FIXME: this MUST get fixed for the new reflocking - */ - if (tty->ldisc.close) - (tty->ldisc.close)(tty); - tty_ldisc_put(tty->ldisc.num); - - /* - * Switch the line discipline back - */ - tty_ldisc_assign(tty, tty_ldisc_get(N_TTY)); - tty_set_termios_ldisc(tty,N_TTY); - if (o_tty) { - /* FIXME: could o_tty be in setldisc here ? */ - clear_bit(TTY_LDISC, &o_tty->flags); - if (o_tty->ldisc.close) - (o_tty->ldisc.close)(o_tty); - tty_ldisc_put(o_tty->ldisc.num); - tty_ldisc_assign(o_tty, tty_ldisc_get(N_TTY)); - tty_set_termios_ldisc(o_tty,N_TTY); - } - /* - * The release_mem function takes care of the details of clearing - * the slots and preserving the termios structure. - */ - release_mem(tty, idx); - -#ifdef CONFIG_UNIX98_PTYS - /* Make this pty number available for reallocation */ - if (devpts) { - down(&allocated_ptys_lock); - idr_remove(&allocated_ptys, idx); - up(&allocated_ptys_lock); - } -#endif - -} - -/** - * 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 current->signal->tty, get_tty_driver and - * init_dev work. tty->count should protect the rest. - * task_lock is held to update task details for sessions - */ - -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)) { - if (!current->signal->tty) { - mutex_unlock(&tty_mutex); - return -ENXIO; - } - driver = current->signal->tty->driver; - index = current->signal->tty->index; - filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */ - /* noctty = 1; */ - goto got_driver; - } -#ifdef CONFIG_VT - if (console_use_vt && (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->driver->open) - retval = tty->driver->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; - } - if (!noctty && - current->signal->leader && - !current->signal->tty && - tty->session == 0) { - task_lock(current); - current->signal->tty = tty; - task_unlock(current); - current->signal->tty_old_pgrp = 0; - tty->session = current->signal->session; - tty->pgrp = process_group(current); - } - return 0; -} - -#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; - int idr_ret; - - nonseekable_open(inode, filp); - - /* find a device that is not in use. */ - down(&allocated_ptys_lock); - if (!idr_pre_get(&allocated_ptys, GFP_KERNEL)) { - up(&allocated_ptys_lock); - return -ENOMEM; - } - idr_ret = idr_get_new(&allocated_ptys, NULL, &index); - if (idr_ret < 0) { - up(&allocated_ptys_lock); - if (idr_ret == -EAGAIN) - return -ENOMEM; - return -EIO; - } - if (index >= pty_limit) { - idr_remove(&allocated_ptys, index); - up(&allocated_ptys_lock); - return -EIO; - } - up(&allocated_ptys_lock); - - 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 = -ENOMEM; - if (devpts_pty_new(tty->link)) - goto out1; - - check_tty_count(tty, "tty_open"); - retval = ptm_driver->open(tty, filp); - if (!retval) - return 0; -out1: - release_dev(filp); - return retval; -out: - down(&allocated_ptys_lock); - idr_remove(&allocated_ptys, index); - up(&allocated_ptys_lock); - return retval; -} -#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_dentry->d_inode, "tty_poll")) - return 0; - - ld = tty_ldisc_ref_wait(tty); - if (ld->poll) - ret = (ld->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; - int retval; - - tty = (struct tty_struct *)filp->private_data; - if (tty_paranoia_check(tty, filp->f_dentry->d_inode, "tty_fasync")) - return 0; - - retval = fasync_helper(fd, filp, on, &tty->fasync); - if (retval <= 0) - return retval; - - if (on) { - if (!waitqueue_active(&tty->read_wait)) - tty->minimum_to_wake = 1; - retval = f_setown(filp, (-tty->pgrp) ? : current->pid, 0); - if (retval) - return retval; - } else { - if (!tty->fasync && !waitqueue_active(&tty->read_wait)) - tty->minimum_to_wake = N_TTY_BUF_SIZE; - } - return 0; -} - -/** - * tiocsti - fake input character - * @tty: tty to fake input into - * @p: pointer to character - * - * Fake input to a tty device. Does the neccessary 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 - */ - -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->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. No - * locking is done. - * - * FIXME: Returning random values racing a window size set is wrong - * should lock here against that - */ - -static int tiocgwinsz(struct tty_struct *tty, struct winsize __user * arg) -{ - if (copy_to_user(arg, &tty->winsize, sizeof(*arg))) - return -EFAULT; - 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: - * The console_sem is used to ensure we do not try and resize - * the console twice at once. - * FIXME: Two racing size sets may leave the console and kernel - * parameters disagreeing. Is this exploitable ? - * FIXME: Random values racing a window size get is wrong - * should lock here against that - */ - -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 (!memcmp(&tmp_ws, &tty->winsize, sizeof(*arg))) - return 0; -#ifdef CONFIG_VT - if (tty->driver->type == TTY_DRIVER_TYPE_CONSOLE) { - int rc; - - acquire_console_sem(); - rc = vc_resize(tty->driver_data, tmp_ws.ws_col, tmp_ws.ws_row); - release_console_sem(); - if (rc) - return -ENXIO; - } -#endif - if (tty->pgrp > 0) - kill_pg(tty->pgrp, SIGWINCH, 1); - if ((real_tty->pgrp != tty->pgrp) && (real_tty->pgrp > 0)) - kill_pg(real_tty->pgrp, SIGWINCH, 1); - tty->winsize = tmp_ws; - real_tty->winsize = tmp_ws; - return 0; -} - -/** - * 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; - - if (nonblock) - file->f_flags |= O_NONBLOCK; - else - file->f_flags &= ~O_NONBLOCK; - 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 tasklist lock internally to walk sessions - * Takes task_lock() when updating signal->tty - * - * FIXME: tty_mutex is needed to protect signal->tty references. - * FIXME: why task_lock on the signal->tty reference ?? - * - */ - -static int tiocsctty(struct tty_struct *tty, int arg) -{ - struct task_struct *p; - - if (current->signal->leader && - (current->signal->session == tty->session)) - return 0; - /* - * The process must be a session leader and - * not have a controlling tty already. - */ - if (!current->signal->leader || current->signal->tty) - return -EPERM; - if (tty->session > 0) { - /* - * 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); - do_each_task_pid(tty->session, PIDTYPE_SID, p) { - p->signal->tty = NULL; - } while_each_task_pid(tty->session, PIDTYPE_SID, p); - read_unlock(&tasklist_lock); - } else - return -EPERM; - } - task_lock(current); - current->signal->tty = tty; - task_unlock(current); - current->signal->tty_old_pgrp = 0; - tty->session = current->signal->session; - tty->pgrp = process_group(current); - return 0; -} - -/** - * 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 ->signal->tty is safe. - */ - -static int tiocgpgrp(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; - return put_user(real_tty->pgrp, p); -} - -/** - * 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: None - * - * FIXME: current->signal->tty referencing is unsafe. - */ - -static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) -{ - pid_t pgrp; - 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 != current->signal->session)) - return -ENOTTY; - if (get_user(pgrp, p)) - return -EFAULT; - if (pgrp < 0) - return -EINVAL; - if (session_of_pgrp(pgrp) != current->signal->session) - return -EPERM; - real_tty->pgrp = pgrp; - return 0; -} - -/** - * 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 ->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 <= 0) - return -ENOTTY; - return put_user(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; - - if (get_user(ldisc, p)) - return -EFAULT; - return tty_set_ldisc(tty, ldisc); -} - -/** - * 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: - * None - * - * FIXME: - * What if two overlap - */ - -static int send_break(struct tty_struct *tty, unsigned int duration) -{ - tty->driver->break_ctl(tty, -1); - if (!signal_pending(current)) { - msleep_interruptible(duration); - } - tty->driver->break_ctl(tty, 0); - if (signal_pending(current)) - return -EINTR; - return 0; -} - -/** - * 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->driver->tiocmget) { - retval = tty->driver->tiocmget(tty, file); - - if (retval >= 0) - retval = put_user(retval, p); - } - return retval; -} - -/** - * 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 = -EINVAL; - - if (tty->driver->tiocmset) { - unsigned int set, clear, val; - - 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; - - retval = tty->driver->tiocmset(tty, file, set, clear); - } - return retval; -} - -/* - * Split this up, as gcc can choke on it otherwise.. - */ -int tty_ioctl(struct inode * inode, 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; - - 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; - - /* - * Break handling by driver - */ - if (!tty->driver->break_ctl) { - switch(cmd) { - case TIOCSBRK: - case TIOCCBRK: - if (tty->driver->ioctl) - return tty->driver->ioctl(tty, file, cmd, arg); - return -EINVAL; - - /* These two ioctl's always return success; even if */ - /* the driver doesn't support them. */ - case TCSBRK: - case TCSBRKP: - if (!tty->driver->ioctl) - return 0; - retval = tty->driver->ioctl(tty, file, cmd, arg); - if (retval == -ENOIOCTLCMD) - retval = 0; - return retval; - } - } - - /* - * 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; - } - - 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: - /* FIXME: taks lock or tty_mutex ? */ - if (current->signal->tty != tty) - return -ENOTTY; - if (current->signal->leader) - disassociate_ctty(0); - task_lock(current); - current->signal->tty = NULL; - task_unlock(current); - 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: - /* FIXME: check this is ok */ - return put_user(tty->ldisc.num, (int __user *)p); - case TIOCSETD: - return tiocsetd(tty, p); -#ifdef CONFIG_VT - case TIOCLINUX: - return tioclinux(tty, arg); -#endif - /* - * Break handling - */ - case TIOCSBRK: /* Turn break on, unconditionally */ - tty->driver->break_ctl(tty, -1); - return 0; - - case TIOCCBRK: /* Turn break off, unconditionally */ - tty->driver->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); - } - if (tty->driver->ioctl) { - retval = (tty->driver->ioctl)(tty, file, cmd, arg); - if (retval != -ENOIOCTLCMD) - return retval; - } - ld = tty_ldisc_ref_wait(tty); - retval = -EINVAL; - if (ld->ioctl) { - retval = ld->ioctl(tty, file, cmd, arg); - if (retval == -ENOIOCTLCMD) - retval = -EINVAL; - } - tty_ldisc_deref(ld); - return retval; -} - - -/* - * 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 - */ -static void __do_SAK(void *arg) -{ -#ifdef TTY_SOFT_SAK - tty_hangup(tty); -#else - struct tty_struct *tty = arg; - struct task_struct *g, *p; - int session; - int i; - struct file *filp; - struct tty_ldisc *disc; - struct fdtable *fdt; - - if (!tty) - return; - session = tty->session; - - /* We don't want an ldisc switch during this */ - disc = tty_ldisc_ref(tty); - if (disc && disc->flush_buffer) - disc->flush_buffer(tty); - tty_ldisc_deref(disc); - - if (tty->driver->flush_buffer) - tty->driver->flush_buffer(tty); - - read_lock(&tasklist_lock); - /* Kill the entire session */ - do_each_task_pid(session, PIDTYPE_SID, p) { - printk(KERN_NOTICE "SAK: killed process %d" - " (%s): p->signal->session==tty->session\n", - p->pid, p->comm); - send_sig(SIGKILL, p, 1); - } while_each_task_pid(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): p->signal->session==tty->session\n", - p->pid, 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", - p->pid, 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 -} - -/* - * 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; - PREPARE_WORK(&tty->SAK_work, __do_SAK, tty); - schedule_work(&tty->SAK_work); -} - -EXPORT_SYMBOL(do_SAK); - -/** - * flush_to_ldisc - * @private_: tty structure passed from work queue. - * - * This routine is called out of the software interrupt to flush data - * from the buffer chain to the line discipline. - * - * Locking: holds tty->buf.lock to guard buffer list. Drops the lock - * while invoking the line discipline receive_buf method. The - * receive_buf method is single threaded for each tty instance. - */ - -static void flush_to_ldisc(void *private_) -{ - struct tty_struct *tty = (struct tty_struct *) private_; - unsigned long flags; - struct tty_ldisc *disc; - struct tty_buffer *tbuf, *head; - char *char_buf; - unsigned char *flag_buf; - - disc = tty_ldisc_ref(tty); - if (disc == NULL) /* !TTY_LDISC */ - return; - - spin_lock_irqsave(&tty->buf.lock, flags); - head = tty->buf.head; - if (head != NULL) { - tty->buf.head = NULL; - for (;;) { - int count = head->commit - head->read; - if (!count) { - if (head->next == NULL) - break; - tbuf = head; - head = head->next; - tty_buffer_free(tty, tbuf); - continue; - } - if (!tty->receive_room) { - schedule_delayed_work(&tty->buf.work, 1); - break; - } - if (count > tty->receive_room) - count = tty->receive_room; - char_buf = head->char_buf_ptr + head->read; - flag_buf = head->flag_buf_ptr + head->read; - head->read += count; - spin_unlock_irqrestore(&tty->buf.lock, flags); - disc->receive_buf(tty, char_buf, flag_buf, count); - spin_lock_irqsave(&tty->buf.lock, flags); - } - tty->buf.head = head; - } - spin_unlock_irqrestore(&tty->buf.lock, flags); - - tty_ldisc_deref(disc); -} - -/* - * Routine which returns the baud rate of the tty - * - * Note that the baud_table needs to be kept in sync with the - * include/asm/termbits.h file. - */ -static int baud_table[] = { - 0, 50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400, 4800, - 9600, 19200, 38400, 57600, 115200, 230400, 460800, -#ifdef __sparc__ - 76800, 153600, 307200, 614400, 921600 -#else - 500000, 576000, 921600, 1000000, 1152000, 1500000, 2000000, - 2500000, 3000000, 3500000, 4000000 -#endif -}; - -static int n_baud_table = ARRAY_SIZE(baud_table); - -/** - * tty_termios_baud_rate - * @termios: termios structure - * - * Convert termios baud rate data into a speed. This should be called - * with the termios lock held if this termios is a terminal termios - * structure. May change the termios data. - * - * Locking: none - */ - -int tty_termios_baud_rate(struct termios *termios) -{ - unsigned int cbaud; - - cbaud = termios->c_cflag & CBAUD; - - if (cbaud & CBAUDEX) { - cbaud &= ~CBAUDEX; - - if (cbaud < 1 || cbaud + 15 > n_baud_table) - termios->c_cflag &= ~CBAUDEX; - else - cbaud += 15; - } - return baud_table[cbaud]; -} - -EXPORT_SYMBOL(tty_termios_baud_rate); - -/** - * tty_get_baud_rate - get tty bit rates - * @tty: tty to query - * - * Returns the baud rate as an integer for this terminal. The - * termios lock must be held by the caller and the terminal bit - * flags may be updated. - * - * Locking: none - */ - -int tty_get_baud_rate(struct tty_struct *tty) -{ - int baud = tty_termios_baud_rate(tty->termios); - - if (baud == 38400 && tty->alt_speed) { - if (!tty->warned) { - printk(KERN_WARNING "Use of setserial/setrocket to " - "set SPD_* flags is deprecated\n"); - tty->warned = 1; - } - baud = tty->alt_speed; - } - - return baud; -} - -EXPORT_SYMBOL(tty_get_baud_rate); - -/** - * tty_flip_buffer_push - terminal - * @tty: tty to push - * - * Queue a push of the terminal flip buffers to the line discipline. This - * function must not be called from IRQ context if tty->low_latency is set. - * - * In the event of the queue being busy for flipping the work will be - * held off and retried later. - * - * Locking: tty buffer lock. Driver locks in low latency mode. - */ - -void tty_flip_buffer_push(struct tty_struct *tty) -{ - unsigned long flags; - spin_lock_irqsave(&tty->buf.lock, flags); - if (tty->buf.tail != NULL) - tty->buf.tail->commit = tty->buf.tail->used; - spin_unlock_irqrestore(&tty->buf.lock, flags); - - if (tty->low_latency) - flush_to_ldisc((void *) tty); - else - schedule_delayed_work(&tty->buf.work, 1); -} - -EXPORT_SYMBOL(tty_flip_buffer_push); - - -/** - * 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_assign(tty, tty_ldisc_get(N_TTY)); - tty->pgrp = -1; - tty->overrun_time = jiffies; - tty->buf.head = tty->buf.tail = NULL; - tty_buffer_init(tty); - INIT_WORK(&tty->buf.work, flush_to_ldisc, tty); - init_MUTEX(&tty->buf.pty_sem); - init_MUTEX(&tty->termios_sem); - init_waitqueue_head(&tty->write_wait); - init_waitqueue_head(&tty->read_wait); - INIT_WORK(&tty->hangup_work, do_tty_hangup, tty); - mutex_init(&tty->atomic_read_lock); - mutex_init(&tty->atomic_write_lock); - spin_lock_init(&tty->read_lock); - INIT_LIST_HEAD(&tty->tty_files); - INIT_WORK(&tty->SAK_work, NULL, NULL); -} - -/* - * The default put_char routine if the driver did not define one. - */ - -static void tty_default_put_char(struct tty_struct *tty, unsigned char ch) -{ - tty->driver->write(tty, &ch, 1); -} - -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 class 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 class_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 class_device_create(tty_class, NULL, dev, device, "%s", 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) -{ - class_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 = kmalloc(sizeof(struct tty_driver), GFP_KERNEL); - if (driver) { - memset(driver, 0, sizeof(struct tty_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, struct tty_operations *op) -{ - driver->open = op->open; - driver->close = op->close; - driver->write = op->write; - driver->put_char = op->put_char; - driver->flush_chars = op->flush_chars; - driver->write_room = op->write_room; - driver->chars_in_buffer = op->chars_in_buffer; - driver->ioctl = op->ioctl; - driver->set_termios = op->set_termios; - driver->throttle = op->throttle; - driver->unthrottle = op->unthrottle; - driver->stop = op->stop; - driver->start = op->start; - driver->hangup = op->hangup; - driver->break_ctl = op->break_ctl; - driver->flush_buffer = op->flush_buffer; - driver->set_ldisc = op->set_ldisc; - driver->wait_until_sent = op->wait_until_sent; - driver->send_xchar = op->send_xchar; - driver->read_proc = op->read_proc; - driver->write_proc = op->write_proc; - driver->tiocmget = op->tiocmget; - driver->tiocmset = op->tiocmset; -} - - -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)) { - p = kmalloc(driver->num * 3 * sizeof(void *), GFP_KERNEL); - if (!p) - return -ENOMEM; - memset(p, 0, driver->num * 3 * sizeof(void *)); - } - - if (!driver->major) { - error = alloc_chrdev_region(&dev, driver->minor_start, driver->num, - (char*)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, - (char*)driver->name); - } - if (error < 0) { - kfree(p); - return error; - } - - if (p) { - driver->ttys = (struct tty_struct **)p; - driver->termios = (struct termios **)(p + driver->num); - driver->termios_locked = (struct termios **)(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; - } - - if (!driver->put_char) - driver->put_char = tty_default_put_char; - - list_add(&driver->tty_drivers, &tty_drivers); - - 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 termios *tp; - void *p; - - if (driver->refcount) - return -EBUSY; - - unregister_chrdev_region(MKDEV(driver->major, driver->minor_start), - driver->num); - - list_del(&driver->tty_drivers); - - /* - * 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); - - -/* - * 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. */ - (void) tty_register_ldisc(N_TTY, &tty_ldisc_N_TTY); - - /* - * set up the console device so that later boot sequences can - * inform about problems etc.. - */ -#ifdef CONFIG_EARLY_PRINTK - disable_early_printk(); -#endif - call = __con_initcall_start; - while (call < __con_initcall_end) { - (*call)(); - call++; - } -} - -#ifdef CONFIG_VT -extern int vty_init(void); -#endif - -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"); - class_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"); - class_device_create(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"); - class_device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx"); -#endif - -#ifdef CONFIG_VT - if (!console_use_vt) - goto out_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"); - class_device_create(tty_class, NULL, MKDEV(TTY_MAJOR, 0), NULL, "tty0"); - - vty_init(); - out_vt: -#endif - return 0; -} -module_init(tty_init); |