diff options
Diffstat (limited to 'drivers/char/tty_io.c')
| -rw-r--r-- | drivers/char/tty_io.c | 1394 |
1 files changed, 415 insertions, 979 deletions
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index daeb8f76697..7053d633369 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -49,7 +49,7 @@ * 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. + * Rewrote tty_init_dev and tty_release_dev to eliminate races. * -- Bill Hawes <whawes@star.net>, June 97 * * Added devfs support. @@ -136,13 +136,6 @@ LIST_HEAD(tty_drivers); /* linked list of tty drivers */ DEFINE_MUTEX(tty_mutex); EXPORT_SYMBOL(tty_mutex); -#ifdef CONFIG_UNIX98_PTYS -extern struct tty_driver *ptm_driver; /* Unix98 pty masters; for /dev/ptmx */ -static int ptmx_open(struct inode *, struct file *); -#endif - -static void initialize_tty_struct(struct tty_struct *tty); - static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *); static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *); ssize_t redirected_tty_write(struct file *, const char __user *, @@ -171,13 +164,11 @@ static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty); * Locking: none */ -static struct tty_struct *alloc_tty_struct(void) +struct tty_struct *alloc_tty_struct(void) { return kzalloc(sizeof(struct tty_struct), GFP_KERNEL); } -static void tty_buffer_free_all(struct tty_struct *); - /** * free_tty_struct - free a disused tty * @tty: tty struct to free @@ -187,7 +178,7 @@ static void tty_buffer_free_all(struct tty_struct *); * Locking: none. Must be called after tty is definitely unused */ -static inline void free_tty_struct(struct tty_struct *tty) +void free_tty_struct(struct tty_struct *tty) { kfree(tty->write_buf); tty_buffer_free_all(tty); @@ -263,398 +254,6 @@ static int check_tty_count(struct tty_struct *tty, const char *routine) 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 - */ - -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_flush - flush full tty buffers - * @tty: tty to flush - * - * flush all the buffers containing receive data. Caller must - * hold the buffer lock and must have ensured no parallel flush to - * ldisc is running. - * - * Locking: Caller must hold tty->buf.lock - */ - -static void __tty_buffer_flush(struct tty_struct *tty) -{ - struct tty_buffer *thead; - - while ((thead = tty->buf.head) != NULL) { - tty->buf.head = thead->next; - tty_buffer_free(tty, thead); - } - tty->buf.tail = NULL; -} - -/** - * tty_buffer_flush - flush full tty buffers - * @tty: tty to flush - * - * flush all the buffers containing receive data. If the buffer is - * being processed by flush_to_ldisc then we defer the processing - * to that function - * - * Locking: none - */ - -static void tty_buffer_flush(struct tty_struct *tty) -{ - unsigned long flags; - spin_lock_irqsave(&tty->buf.lock, flags); - - /* If the data is being pushed to the tty layer then we can't - process it here. Instead set a flag and the flush_to_ldisc - path will process the flush request before it exits */ - if (test_bit(TTY_FLUSHING, &tty->flags)) { - set_bit(TTY_FLUSHPENDING, &tty->flags); - spin_unlock_irqrestore(&tty->buf.lock, flags); - wait_event(tty->read_wait, - test_bit(TTY_FLUSHPENDING, &tty->flags) == 0); - return; - } else - __tty_buffer_flush(tty); - spin_unlock_irqrestore(&tty->buf.lock, flags); -} - -/** - * 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); - - - /** * get_tty_driver - find device of a tty * @dev_t: device identifier @@ -675,7 +274,7 @@ static struct tty_driver *get_tty_driver(dev_t device, int *index) if (device < base || device >= base + p->num) continue; *index = device - base; - return p; + return tty_driver_kref_get(p); } return NULL; } @@ -695,13 +294,23 @@ struct tty_driver *tty_find_polling_driver(char *name, int *line) { struct tty_driver *p, *res = NULL; int tty_line = 0; + int len; char *str; + for (str = name; *str; str++) + if ((*str >= '0' && *str <= '9') || *str == ',') + break; + if (!*str) + return NULL; + + len = str - name; + tty_line = simple_strtoul(str, &str, 10); + mutex_lock(&tty_mutex); /* Search through the tty devices to look for a match */ list_for_each_entry(p, &tty_drivers, tty_drivers) { - str = name + strlen(p->name); - tty_line = simple_strtoul(str, &str, 10); + if (strncmp(name, p->name, len) != 0) + continue; if (*str == ',') str++; if (*str == '\0') @@ -709,7 +318,7 @@ struct tty_driver *tty_find_polling_driver(char *name, int *line) if (tty_line >= 0 && tty_line <= p->num && p->ops && p->ops->poll_init && !p->ops->poll_init(p, tty_line, str)) { - res = p; + res = tty_driver_kref_get(p); *line = tty_line; break; } @@ -809,20 +418,6 @@ static const struct file_operations tty_fops = { .fasync = tty_fasync, }; -#ifdef CONFIG_UNIX98_PTYS -static const struct file_operations ptmx_fops = { - .llseek = no_llseek, - .read = tty_read, - .write = tty_write, - .poll = tty_poll, - .unlocked_ioctl = tty_ioctl, - .compat_ioctl = tty_compat_ioctl, - .open = ptmx_open, - .release = tty_release, - .fasync = tty_fasync, -}; -#endif - static const struct file_operations console_fops = { .llseek = no_llseek, .read = tty_read, @@ -943,6 +538,7 @@ static void do_tty_hangup(struct work_struct *work) struct tty_ldisc *ld; int closecount = 0, n; unsigned long flags; + int refs = 0; if (!tty) return; @@ -1009,8 +605,12 @@ static void do_tty_hangup(struct work_struct *work) if (tty->session) { do_each_pid_task(tty->session, PIDTYPE_SID, p) { spin_lock_irq(&p->sighand->siglock); - if (p->signal->tty == tty) + if (p->signal->tty == tty) { p->signal->tty = NULL; + /* We defer the dereferences outside fo + the tasklist lock */ + refs++; + } if (!p->signal->leader) { spin_unlock_irq(&p->sighand->siglock); continue; @@ -1036,6 +636,10 @@ static void do_tty_hangup(struct work_struct *work) tty->ctrl_status = 0; spin_unlock_irqrestore(&tty->ctrl_lock, flags); + /* Account for the p->signal references we killed */ + while (refs--) + tty_kref_put(tty); + /* * If one of the devices matches a console pointer, we * cannot just call hangup() because that will cause @@ -1105,6 +709,23 @@ void tty_vhangup(struct tty_struct *tty) EXPORT_SYMBOL(tty_vhangup); /** + * tty_vhangup_self - process vhangup for own ctty + * + * Perform a vhangup on the current controlling tty + */ + +void tty_vhangup_self(void) +{ + struct tty_struct *tty; + + tty = get_current_tty(); + if (tty) { + tty_vhangup(tty); + tty_kref_put(tty); + } +} + +/** * tty_hung_up_p - was tty hung up * @filp: file pointer of tty * @@ -1157,16 +778,14 @@ void disassociate_ctty(int on_exit) struct pid *tty_pgrp = NULL; - mutex_lock(&tty_mutex); tty = get_current_tty(); if (tty) { tty_pgrp = get_pid(tty->pgrp); lock_kernel(); - mutex_unlock(&tty_mutex); - /* XXX: here we race, there is nothing protecting tty */ if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY) tty_vhangup(tty); unlock_kernel(); + tty_kref_put(tty); } else if (on_exit) { struct pid *old_pgrp; spin_lock_irq(¤t->sighand->siglock); @@ -1178,7 +797,6 @@ void disassociate_ctty(int on_exit) kill_pgrp(old_pgrp, SIGCONT, on_exit); put_pid(old_pgrp); } - mutex_unlock(&tty_mutex); return; } if (tty_pgrp) { @@ -1193,8 +811,6 @@ void disassociate_ctty(int on_exit) current->signal->tty_old_pgrp = NULL; spin_unlock_irq(¤t->sighand->siglock); - mutex_lock(&tty_mutex); - /* It is possible that do_tty_hangup has free'd this tty */ tty = get_current_tty(); if (tty) { unsigned long flags; @@ -1204,13 +820,13 @@ void disassociate_ctty(int on_exit) tty->session = NULL; tty->pgrp = NULL; spin_unlock_irqrestore(&tty->ctrl_lock, flags); + tty_kref_put(tty); } else { #ifdef TTY_DEBUG_HANGUP printk(KERN_DEBUG "error attempted to write to tty [0x%p]" " = NULL", tty); #endif } - mutex_unlock(&tty_mutex); /* Now clear signal->tty under the lock */ read_lock(&tasklist_lock); @@ -1410,19 +1026,19 @@ static inline ssize_t do_tty_write( /* write_buf/write_cnt is protected by the atomic_write_lock mutex */ if (tty->write_cnt < chunk) { - unsigned char *buf; + unsigned char *buf_chunk; if (chunk < 1024) chunk = 1024; - buf = kmalloc(chunk, GFP_KERNEL); - if (!buf) { + buf_chunk = kmalloc(chunk, GFP_KERNEL); + if (!buf_chunk) { ret = -ENOMEM; goto out; } kfree(tty->write_buf); tty->write_cnt = chunk; - tty->write_buf = buf; + tty->write_buf = buf_chunk; } /* Do the write .. */ @@ -1456,6 +1072,31 @@ out: return ret; } +/** + * tty_write_message - write a message to a certain tty, not just the console. + * @tty: the destination tty_struct + * @msg: the message to write + * + * This is used for messages that need to be redirected to a specific tty. + * We don't put it into the syslog queue right now maybe in the future if + * really needed. + * + * We must still hold the BKL and test the CLOSING flag for the moment. + */ + +void tty_write_message(struct tty_struct *tty, char *msg) +{ + lock_kernel(); + if (tty) { + mutex_lock(&tty->atomic_write_lock); + if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags)) + tty->ops->write(tty, msg, strlen(msg)); + tty_write_unlock(tty); + } + unlock_kernel(); + return; +} + /** * tty_write - write method for tty device file @@ -1523,42 +1164,6 @@ ssize_t redirected_tty_write(struct file *file, const char __user *buf, return tty_write(file, buf, count, ppos); } -void tty_port_init(struct tty_port *port) -{ - memset(port, 0, sizeof(*port)); - init_waitqueue_head(&port->open_wait); - init_waitqueue_head(&port->close_wait); - mutex_init(&port->mutex); - port->close_delay = (50 * HZ) / 100; - port->closing_wait = (3000 * HZ) / 100; -} -EXPORT_SYMBOL(tty_port_init); - -int tty_port_alloc_xmit_buf(struct tty_port *port) -{ - /* We may sleep in get_zeroed_page() */ - mutex_lock(&port->mutex); - if (port->xmit_buf == NULL) - port->xmit_buf = (unsigned char *)get_zeroed_page(GFP_KERNEL); - mutex_unlock(&port->mutex); - if (port->xmit_buf == NULL) - return -ENOMEM; - return 0; -} -EXPORT_SYMBOL(tty_port_alloc_xmit_buf); - -void tty_port_free_xmit_buf(struct tty_port *port) -{ - mutex_lock(&port->mutex); - if (port->xmit_buf != NULL) { - free_page((unsigned long)port->xmit_buf); - port->xmit_buf = NULL; - } - mutex_unlock(&port->mutex); -} -EXPORT_SYMBOL(tty_port_free_xmit_buf); - - static char ptychar[] = "pqrstuvwxyzabcde"; /** @@ -1582,7 +1187,7 @@ static void pty_line_name(struct tty_driver *driver, int index, char *p) } /** - * pty_line_name - generate name for a tty + * tty_line_name - generate name for a tty * @driver: the tty driver in use * @index: the minor number * @p: output buffer of at least 7 bytes @@ -1598,10 +1203,148 @@ static void tty_line_name(struct tty_driver *driver, int index, char *p) } /** - * init_dev - initialise a tty device + * tty_driver_lookup_tty() - find an existing tty, if any + * @driver: the driver for the tty + * @idx: the minor number + * + * Return the tty, if found or ERR_PTR() otherwise. + * + * Locking: tty_mutex must be held. If tty is found, the mutex must + * be held until the 'fast-open' is also done. Will change once we + * have refcounting in the driver and per driver locking + */ +struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver, + struct inode *inode, int idx) +{ + struct tty_struct *tty; + + if (driver->ops->lookup) + return driver->ops->lookup(driver, inode, idx); + + tty = driver->ttys[idx]; + return tty; +} + +/** + * tty_init_termios - helper for termios setup + * @tty: the tty to set up + * + * Initialise the termios structures for this tty. Thus runs under + * the tty_mutex currently so we can be relaxed about ordering. + */ + +int tty_init_termios(struct tty_struct *tty) +{ + struct ktermios *tp; + int idx = tty->index; + + tp = tty->driver->termios[idx]; + if (tp == NULL) { + tp = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL); + if (tp == NULL) + return -ENOMEM; + memcpy(tp, &tty->driver->init_termios, + sizeof(struct ktermios)); + tty->driver->termios[idx] = tp; + } + tty->termios = tp; + tty->termios_locked = tp + 1; + + /* Compatibility until drivers always set this */ + tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios); + tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios); + return 0; +} + +/** + * tty_driver_install_tty() - install a tty entry in the driver + * @driver: the driver for the tty + * @tty: the tty + * + * Install a tty object into the driver tables. The tty->index field + * will be set by the time this is called. This method is responsible + * for ensuring any need additional structures are allocated and + * configured. + * + * Locking: tty_mutex for now + */ +static int tty_driver_install_tty(struct tty_driver *driver, + struct tty_struct *tty) +{ + int idx = tty->index; + + if (driver->ops->install) + return driver->ops->install(driver, tty); + + if (tty_init_termios(tty) == 0) { + tty_driver_kref_get(driver); + tty->count++; + driver->ttys[idx] = tty; + return 0; + } + return -ENOMEM; +} + +/** + * tty_driver_remove_tty() - remove a tty from the driver tables + * @driver: the driver for the tty + * @idx: the minor number + * + * Remvoe a tty object from the driver tables. The tty->index field + * will be set by the time this is called. + * + * Locking: tty_mutex for now + */ +static void tty_driver_remove_tty(struct tty_driver *driver, + struct tty_struct *tty) +{ + if (driver->ops->remove) + driver->ops->remove(driver, tty); + else + driver->ttys[tty->index] = NULL; +} + +/* + * tty_reopen() - fast re-open of an open tty + * @tty - the tty to open + * + * Return 0 on success, -errno on error. + * + * Locking: tty_mutex must be held from the time the tty was found + * till this open completes. + */ +static int tty_reopen(struct tty_struct *tty) +{ + struct tty_driver *driver = tty->driver; + + if (test_bit(TTY_CLOSING, &tty->flags)) + return -EIO; + + if (driver->type == TTY_DRIVER_TYPE_PTY && + driver->subtype == PTY_TYPE_MASTER) { + /* + * special case for PTY masters: only one open permitted, + * and the slave side open count is incremented as well. + */ + if (tty->count) + return -EIO; + + tty->link->count++; + } + tty->count++; + tty->driver = driver; /* N.B. why do this every time?? */ + + WARN_ON(!test_bit(TTY_LDISC, &tty->flags)); + + return 0; +} + +/** + * tty_init_dev - initialise a tty device * @driver: tty driver we are opening a device on * @idx: device index - * @tty: returned tty structure + * @ret_tty: returned tty structure + * @first_ok: ok to open a new device (used by ptmx) * * Prepare a tty device. This may not be a "new" clean device but * could also be an active device. The pty drivers require special @@ -1621,37 +1364,16 @@ static void tty_line_name(struct tty_driver *driver, int index, char *p) * 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_init_dev(struct tty_driver *driver, int idx, + int first_ok) { - struct tty_struct *tty, *o_tty; - struct ktermios *tp, **tp_loc, *o_tp, **o_tp_loc; - struct ktermios *ltp, **ltp_loc, *o_ltp, **o_ltp_loc; - int retval = 0; + struct tty_struct *tty; + int retval; - /* check whether we're reopening an existing tty */ - if (driver->flags & TTY_DRIVER_DEVPTS_MEM) { - tty = devpts_get_tty(idx); - /* - * If we don't have a tty here on a slave open, it's because - * the master already started the close process and there's - * no relation between devpts file and tty anymore. - */ - if (!tty && driver->subtype == PTY_TYPE_SLAVE) { - retval = -EIO; - goto end_init; - } - /* - * It's safe from now on because init_dev() is called with - * tty_mutex held and release_dev() won't change tty->count - * or tty->flags without having to grab tty_mutex - */ - if (tty && driver->subtype == PTY_TYPE_MASTER) - tty = tty->link; - } else { - tty = driver->ttys[idx]; - } - if (tty) goto fast_track; + /* Check if pty master is being opened multiple times */ + if (driver->subtype == PTY_TYPE_MASTER && + (driver->flags & TTY_DRIVER_DEVPTS_MEM) && !first_ok) + return ERR_PTR(-EIO); /* * First time open is complex, especially for PTY devices. @@ -1661,189 +1383,69 @@ static int init_dev(struct tty_driver *driver, int idx, * 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; + if (!try_module_get(driver->owner)) + return ERR_PTR(-ENODEV); tty = alloc_tty_struct(); if (!tty) goto fail_no_mem; - initialize_tty_struct(tty); - tty->driver = driver; - tty->ops = driver->ops; - tty->index = idx; - tty_line_name(driver, idx, tty->name); - - if (driver->flags & TTY_DRIVER_DEVPTS_MEM) { - tp_loc = &tty->termios; - ltp_loc = &tty->termios_locked; - } else { - tp_loc = &driver->termios[idx]; - ltp_loc = &driver->termios_locked[idx]; - } + initialize_tty_struct(tty, driver, idx); - if (!*tp_loc) { - tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL); - if (!tp) - goto free_mem_out; - *tp = driver->init_termios; - } - - if (!*ltp_loc) { - ltp = kzalloc(sizeof(struct ktermios), GFP_KERNEL); - if (!ltp) - goto free_mem_out; - } - - if (driver->type == TTY_DRIVER_TYPE_PTY) { - o_tty = alloc_tty_struct(); - if (!o_tty) - goto free_mem_out; - initialize_tty_struct(o_tty); - o_tty->driver = driver->other; - o_tty->ops = driver->ops; - o_tty->index = idx; - tty_line_name(driver->other, idx, o_tty->name); - - if (driver->flags & TTY_DRIVER_DEVPTS_MEM) { - o_tp_loc = &o_tty->termios; - o_ltp_loc = &o_tty->termios_locked; - } else { - o_tp_loc = &driver->other->termios[idx]; - o_ltp_loc = &driver->other->termios_locked[idx]; - } - - if (!*o_tp_loc) { - o_tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL); - if (!o_tp) - goto free_mem_out; - *o_tp = driver->other->init_termios; - } - - if (!*o_ltp_loc) { - o_ltp = kzalloc(sizeof(struct ktermios), GFP_KERNEL); - if (!o_ltp) - goto free_mem_out; - } - - /* - * Everything allocated ... set up the o_tty structure. - */ - if (!(driver->other->flags & TTY_DRIVER_DEVPTS_MEM)) - driver->other->ttys[idx] = o_tty; - if (!*o_tp_loc) - *o_tp_loc = o_tp; - if (!*o_ltp_loc) - *o_ltp_loc = o_ltp; - o_tty->termios = *o_tp_loc; - o_tty->termios_locked = *o_ltp_loc; - driver->other->refcount++; - if (driver->subtype == PTY_TYPE_MASTER) - o_tty->count++; - - /* Establish the links in both directions */ - tty->link = o_tty; - o_tty->link = tty; + retval = tty_driver_install_tty(driver, tty); + if (retval < 0) { + free_tty_struct(tty); + module_put(driver->owner); + return ERR_PTR(retval); } /* - * All structures have been allocated, so now we install them. - * Failures after this point use release_tty to clean up, so - * there's no need to null out the local pointers. - */ - if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM)) - driver->ttys[idx] = tty; - - if (!*tp_loc) - *tp_loc = tp; - if (!*ltp_loc) - *ltp_loc = ltp; - tty->termios = *tp_loc; - tty->termios_locked = *ltp_loc; - /* Compatibility until drivers always set this */ - tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios); - tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios); - driver->refcount++; - tty->count++; - - /* * Structures all installed ... call the ldisc open routines. * If we fail here just call release_tty to clean up. No need * to decrement the use counts, as release_tty doesn't care. */ - retval = tty_ldisc_setup(tty, o_tty); - + retval = tty_ldisc_setup(tty, tty->link); if (retval) goto release_mem_out; - goto success; - - /* - * This fast open can be used if the tty is already open. - * No memory is allocated, and the only failures are from - * attempting to open a closing tty or attempting multiple - * opens on a pty master. - */ -fast_track: - if (test_bit(TTY_CLOSING, &tty->flags)) { - retval = -EIO; - goto end_init; - } - if (driver->type == TTY_DRIVER_TYPE_PTY && - driver->subtype == PTY_TYPE_MASTER) { - /* - * special case for PTY masters: only one open permitted, - * and the slave side open count is incremented as well. - */ - if (tty->count) { - retval = -EIO; - goto end_init; - } - tty->link->count++; - } - tty->count++; - tty->driver = driver; /* N.B. why do this every time?? */ - - /* FIXME */ - if (!test_bit(TTY_LDISC, &tty->flags)) - printk(KERN_ERR "init_dev but no ldisc\n"); -success: - *ret_tty = tty; - - /* All paths come through here to release the mutex */ -end_init: - return retval; - - /* Release locally allocated memory ... nothing placed in slots */ -free_mem_out: - kfree(o_tp); - if (o_tty) - free_tty_struct(o_tty); - kfree(ltp); - kfree(tp); - free_tty_struct(tty); + return tty; fail_no_mem: module_put(driver->owner); - retval = -ENOMEM; - goto end_init; + return ERR_PTR(-ENOMEM); /* call the tty release_tty routine to clean out this slot */ release_mem_out: if (printk_ratelimit()) - printk(KERN_INFO "init_dev: ldisc open failed, " + printk(KERN_INFO "tty_init_dev: ldisc open failed, " "clearing slot %d\n", idx); release_tty(tty, idx); - goto end_init; + return ERR_PTR(retval); +} + +void tty_free_termios(struct tty_struct *tty) +{ + struct ktermios *tp; + int idx = tty->index; + /* Kill this flag and push into drivers for locking etc */ + if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) { + /* FIXME: Locking on ->termios array */ + tp = tty->termios; + tty->driver->termios[idx] = NULL; + kfree(tp); + } } +EXPORT_SYMBOL(tty_free_termios); + +void tty_shutdown(struct tty_struct *tty) +{ + tty_driver_remove_tty(tty->driver, tty); + tty_free_termios(tty); +} +EXPORT_SYMBOL(tty_shutdown); /** * release_one_tty - release tty structure memory + * @kref: kref of tty we are obliterating * * Releases memory associated with a tty structure, and clears out the * driver table slots. This function is called when a device is no longer @@ -1853,31 +1455,19 @@ release_mem_out: * tty_mutex - sometimes only * takes the file list lock internally when working on the list * of ttys that the driver keeps. - * FIXME: should we require tty_mutex is held here ?? */ -static void release_one_tty(struct tty_struct *tty, int idx) +static void release_one_tty(struct kref *kref) { - int devpts = tty->driver->flags & TTY_DRIVER_DEVPTS_MEM; - struct ktermios *tp; - - if (!devpts) - tty->driver->ttys[idx] = NULL; - - if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) { - tp = tty->termios; - if (!devpts) - tty->driver->termios[idx] = NULL; - kfree(tp); - - tp = tty->termios_locked; - if (!devpts) - tty->driver->termios_locked[idx] = NULL; - kfree(tp); - } - + struct tty_struct *tty = container_of(kref, struct tty_struct, kref); + struct tty_driver *driver = tty->driver; + if (tty->ops->shutdown) + tty->ops->shutdown(tty); + else + tty_shutdown(tty); tty->magic = 0; - tty->driver->refcount--;< |