X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=drivers%2Fchar%2Ftty_io.c;h=52bd25904b2a0263bb807b882c54c2e3b840f0d2;hb=refs%2Fheads%2Fvserver;hp=f5e3bce8731bfc21cd597af3a6a879ca9b8d6c23;hpb=f7f1b0f1e2fbadeab12d24236000e778aa9b1ead;p=linux-2.6.git diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index f5e3bce87..52bd25904 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -65,7 +65,6 @@ * alloc_tty_struct() always uses kmalloc() -- Andrew Morton 17Mar01 */ -#include #include #include #include @@ -94,6 +93,7 @@ #include #include #include +#include #include #include @@ -101,23 +101,24 @@ #include #include #include -#include -#include #include +#include #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 */ +struct ktermios tty_std_termios = { /* for the benefit of tty drivers */ .c_iflag = ICRNL | IXON, .c_oflag = OPOST | ONLCR, .c_cflag = B38400 | CS8 | CREAD | HUPCL, .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOKE | IEXTEN, - .c_cc = INIT_C_CC + .c_cc = INIT_C_CC, + .c_ispeed = 38400, + .c_ospeed = 38400 }; EXPORT_SYMBOL(tty_std_termios); @@ -128,9 +129,10 @@ EXPORT_SYMBOL(tty_std_termios); LIST_HEAD(tty_drivers); /* linked list of tty drivers */ -/* Semaphore to protect creating and releasing a tty. This is shared with +/* Mutex to protect creating and releasing a tty. This is shared with vt.c for deeply disgusting hack reasons */ -DECLARE_MUTEX(tty_sem); +DEFINE_MUTEX(tty_mutex); +EXPORT_SYMBOL(tty_mutex); #ifdef CONFIG_UNIX98_PTYS extern struct tty_driver *ptm_driver; /* Unix98 pty masters; for /dev/ptmx */ @@ -153,28 +155,54 @@ 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); -extern void rs_360_init(void); 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 + */ 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; + 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 + * + * 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); + memset(tty, 0xDEADDEAD, sizeof(struct tty_struct)); 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. */ @@ -226,22 +254,366 @@ static int check_tty_count(struct tty_struct *tty, const char *routine) "!= #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 + */ + +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_mutex */ static void tty_set_termios_ldisc(struct tty_struct *tty, int num) { - down(&tty->termios_sem); + mutex_lock(&tty->termios_mutex); tty->termios->c_line = num; - up(&tty->termios_sem); + mutex_unlock(&tty->termios_mutex); } /* @@ -252,7 +624,20 @@ static void tty_set_termios_ldisc(struct tty_struct *tty, int num) 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 */ +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) { @@ -263,24 +648,60 @@ int tty_register_ldisc(int disc, struct tty_ldisc *new_ldisc) return -EINVAL; spin_lock_irqsave(&tty_ldisc_lock, flags); - if (new_ldisc) { - tty_ldiscs[disc] = *new_ldisc; - tty_ldiscs[disc].num = disc; - tty_ldiscs[disc].flags |= LDISC_FLAG_DEFINED; - tty_ldiscs[disc].refcount = 0; - } else { - if(tty_ldiscs[disc].refcount) - ret = -EBUSY; - else - tty_ldiscs[disc].flags &= ~LDISC_FLAG_DEFINED; - } + 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; @@ -309,25 +730,47 @@ struct tty_ldisc *tty_ldisc_get(int disc) 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; - if (disc < N_TTY || disc >= NR_LDISCS) - BUG(); + BUG_ON(disc < N_TTY || disc >= NR_LDISCS); spin_lock_irqsave(&tty_ldisc_lock, flags); ld = &tty_ldiscs[disc]; - if(ld->refcount == 0) - BUG(); - ld->refcount --; + 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; @@ -342,6 +785,8 @@ static void tty_ldisc_assign(struct tty_struct *tty, struct tty_ldisc *ld) * 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) @@ -373,6 +818,8 @@ static int tty_ldisc_try(struct tty_struct *tty) * 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) @@ -393,6 +840,8 @@ EXPORT_SYMBOL_GPL(tty_ldisc_ref_wait); * 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) @@ -410,14 +859,15 @@ EXPORT_SYMBOL_GPL(tty_ldisc_ref); * * 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; - if(ld == NULL) - BUG(); + BUG_ON(ld == NULL); spin_lock_irqsave(&tty_ldisc_lock, flags); if(ld->refcount == 0) @@ -455,25 +905,26 @@ static void tty_ldisc_enable(struct tty_struct *tty) * * Set the discipline of a tty line. Must be called from a process * context. + * + * Locking: takes tty_ldisc_lock. + * called functions take termios_mutex */ static int tty_set_ldisc(struct tty_struct *tty, int ldisc) { - int retval = 0; - struct tty_ldisc o_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: - if (tty->ldisc.num == ldisc) - return 0; /* We are already in the desired discipline */ - ld = tty_ldisc_get(ldisc); /* Eduardo Blanco */ /* Cyrus Durgin */ @@ -484,48 +935,85 @@ restart: if (ld == NULL) return -EINVAL; - o_ldisc = tty->ldisc; + /* + * 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) - { - /* Free the new ldisc we grabbed. Must drop the lock - first. */ + 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); - /* - * 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; + ld = tty_ldisc_ref_wait(tty); + tty_ldisc_deref(ld); goto restart; } - clear_bit(TTY_LDISC, &tty->flags); - clear_bit(TTY_DONT_FLIP, &tty->flags); + + 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->flip.work); + + work = cancel_delayed_work(&tty->buf.work); /* - * Wait for ->hangup_work and ->flip.work handlers to terminate + * Wait for ->hangup_work and ->buf.work handlers to terminate */ flush_scheduled_work(); @@ -573,17 +1061,27 @@ restart: */ 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->flip.work, 1); + if (work) + schedule_delayed_work(&tty->buf.work, 1); return retval; } -/* - * This routine returns a tty driver structure, given a device number +/** + * 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; @@ -598,11 +1096,17 @@ static struct tty_driver *get_tty_driver(dev_t device, int *index) return NULL; } -/* - * 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) +/** + * 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) @@ -647,7 +1151,7 @@ static int hung_up_tty_ioctl(struct inode * inode, struct file * file, return cmd == TIOCSPGRP ? -ENOTTY : -EIO; } -static struct file_operations tty_fops = { +static const struct file_operations tty_fops = { .llseek = no_llseek, .read = tty_read, .write = tty_write, @@ -659,7 +1163,7 @@ static struct file_operations tty_fops = { }; #ifdef CONFIG_UNIX98_PTYS -static struct file_operations ptmx_fops = { +static const struct file_operations ptmx_fops = { .llseek = no_llseek, .read = tty_read, .write = tty_write, @@ -671,7 +1175,7 @@ static struct file_operations ptmx_fops = { }; #endif -static struct file_operations console_fops = { +static const struct file_operations console_fops = { .llseek = no_llseek, .read = tty_read, .write = redirected_tty_write, @@ -682,7 +1186,7 @@ static struct file_operations console_fops = { .fasync = tty_fasync, }; -static struct file_operations hung_up_tty_fops = { +static const struct file_operations hung_up_tty_fops = { .llseek = no_llseek, .read = hung_up_tty_read, .write = hung_up_tty_write, @@ -739,15 +1243,49 @@ void tty_ldisc_flush(struct tty_struct *tty) } EXPORT_SYMBOL_GPL(tty_ldisc_flush); + +/** + * tty_reset_termios - reset terminal state + * @tty: tty to reset + * + * Restore a terminal to the driver default state + */ + +static void tty_reset_termios(struct tty_struct *tty) +{ + mutex_lock(&tty->termios_mutex); + *tty->termios = tty->driver->init_termios; + tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios); + tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios); + mutex_unlock(&tty->termios_mutex); +} -/* - * 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.. +/** + * do_tty_hangup - actual handler for hangup events + * @work: tty device + * + * This can be called by the "eventd" kernel thread. That is process + * synchronous but doesn't hold any locks, so we need to make sure we + * have the appropriate locks for what we're doing. + * + * The hangup event clears any pending redirections onto the hung up + * device. It ensures future writes will error and it does the needed + * line discipline hangup and signal delivery. The tty object itself + * remains intact. + * + * Locking: + * BKL + * redirect lock for undoing redirection + * file list lock for manipulating list of ttys + * tty_ldisc_lock from called functions + * termios_mutex resetting termios data + * tasklist_lock to walk task list for hangup event + * ->siglock to protect ->signal/->sighand */ -static void do_tty_hangup(void *data) +static void do_tty_hangup(struct work_struct *work) { - struct tty_struct *tty = (struct tty_struct *) data; + struct tty_struct *tty = + container_of(work, struct tty_struct, hangup_work); struct file * cons_filp = NULL; struct file *filp, *f = NULL; struct task_struct *p; @@ -770,7 +1308,7 @@ static void do_tty_hangup(void *data) 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_list) { + 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) @@ -809,11 +1347,7 @@ static void do_tty_hangup(void *data) * N_TTY. */ if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) - { - down(&tty->termios_sem); - *tty->termios = tty->driver->init_termios; - up(&tty->termios_sem); - } + tty_reset_termios(tty); /* Defer ldisc switch */ /* tty_deferred_ldisc_switch(N_TTY); @@ -824,14 +1358,18 @@ static void do_tty_hangup(void *data) read_lock(&tasklist_lock); if (tty->session > 0) { do_each_task_pid(tty->session, PIDTYPE_SID, p) { + spin_lock_irq(&p->sighand->siglock); if (p->signal->tty == tty) p->signal->tty = NULL; - if (!p->signal->leader) + if (!p->signal->leader) { + spin_unlock_irq(&p->sighand->siglock); continue; - send_group_sig_info(SIGHUP, SEND_SIG_PRIV, p); - send_group_sig_info(SIGCONT, SEND_SIG_PRIV, p); + } + __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; + spin_unlock_irq(&p->sighand->siglock); } while_each_task_pid(tty->session, PIDTYPE_SID, p); } read_unlock(&tasklist_lock); @@ -868,6 +1406,14 @@ static void do_tty_hangup(void *data) 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 @@ -880,6 +1426,15 @@ void tty_hangup(struct tty_struct * tty) 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 @@ -887,10 +1442,18 @@ void tty_vhangup(struct tty_struct * tty) printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf)); #endif - do_tty_hangup((void *) tty); + do_tty_hangup(&tty->hangup_work); } EXPORT_SYMBOL(tty_vhangup); +/** + * tty_hung_up_p - was tty hung up + * @filp: file pointer of tty + * + * Return true if the tty has been subject to a vhangup or a carrier + * loss + */ + int tty_hung_up_p(struct file * filp) { return (filp->f_op == &hung_up_tty_fops); @@ -898,40 +1461,61 @@ int tty_hung_up_p(struct file * filp) EXPORT_SYMBOL(tty_hung_up_p); -/* - * This function is typically called only by the session leader, when - * it wants to disassociate itself from its controlling tty. +static void session_clear_tty(pid_t session) +{ + struct task_struct *p; + do_each_task_pid(session, PIDTYPE_SID, p) { + proc_clear_tty(p); + } while_each_task_pid(session, PIDTYPE_SID, p); +} + +/** + * disassociate_ctty - disconnect controlling tty + * @on_exit: true if exiting so need to "hang up" the session + * + * This function is typically called only by the session leader, when + * it wants to disassociate itself from its controlling tty. * - * It performs the following functions: + * 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. + * The argument on_exit is set to 1 if called when a process is + * exiting; it is 0 if called by the ioctl TIOCNOTTY. + * + * Locking: + * BKL is taken for hysterical raisins + * tty_mutex is taken to protect tty + * ->siglock is taken to protect ->signal/->sighand + * tasklist_lock is taken to walk process list for sessions + * ->siglock is taken to protect ->signal/->sighand */ + void disassociate_ctty(int on_exit) { struct tty_struct *tty; - struct task_struct *p; int tty_pgrp = -1; + int session; lock_kernel(); - down(&tty_sem); - tty = current->signal->tty; + mutex_lock(&tty_mutex); + tty = get_current_tty(); if (tty) { tty_pgrp = tty->pgrp; - up(&tty_sem); + 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); } 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); + pid_t old_pgrp = current->signal->tty_old_pgrp; + if (old_pgrp) { + kill_pg(old_pgrp, SIGHUP, on_exit); + kill_pg(old_pgrp, SIGCONT, on_exit); } - up(&tty_sem); + mutex_unlock(&tty_mutex); unlock_kernel(); return; } @@ -941,22 +1525,51 @@ void disassociate_ctty(int on_exit) kill_pg(tty_pgrp, SIGCONT, on_exit); } - /* Must lock changes to tty_old_pgrp */ - down(&tty_sem); + spin_lock_irq(¤t->sighand->siglock); current->signal->tty_old_pgrp = 0; - tty->session = 0; - tty->pgrp = -1; + session = process_session(current); + 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) { + tty->session = 0; + tty->pgrp = 0; + } 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); - do_each_task_pid(current->signal->session, PIDTYPE_SID, p) { - p->signal->tty = NULL; - } while_each_task_pid(current->signal->session, PIDTYPE_SID, p); + session_clear_tty(session); read_unlock(&tasklist_lock); - up(&tty_sem); 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) @@ -973,6 +1586,19 @@ void stop_tty(struct tty_struct *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) @@ -993,6 +1619,23 @@ void start_tty(struct tty_struct *tty) EXPORT_SYMBOL(start_tty); +/** + * tty_read - read method for tty device files + * @file: pointer to tty file + * @buf: user buffer + * @count: size of user buffer + * @ppos: unused + * + * Perform the read system call function on this terminal device. Checks + * for hung up devices before calling the line discipline method. + * + * Locking: + * Locks the line discipline internally while needed + * 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) { @@ -1002,7 +1645,7 @@ static ssize_t tty_read(struct file * file, char __user * buf, size_t count, struct tty_ldisc *ld; tty = (struct tty_struct *)file->private_data; - inode = file->f_dentry->d_inode; + inode = file->f_path.dentry->d_inode; if (tty_paranoia_check(tty, inode, "tty_read")) return -EIO; if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags))) @@ -1037,7 +1680,8 @@ static inline ssize_t do_tty_write( ssize_t ret = 0, written = 0; unsigned int chunk; - if (down_interruptible(&tty->atomic_write)) { + /* FIXME: O_NDELAY ... */ + if (mutex_lock_interruptible(&tty->atomic_write_lock)) { return -ERESTARTSYS; } @@ -1053,6 +1697,9 @@ static inline ssize_t do_tty_write( * 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)) @@ -1060,7 +1707,7 @@ static inline ssize_t do_tty_write( if (count < chunk) chunk = count; - /* write_buf/write_cnt is protected by the atomic_write semaphore */ + /* write_buf/write_cnt is protected by the atomic_write_lock mutex */ if (tty->write_cnt < chunk) { unsigned char *buf; @@ -1069,7 +1716,7 @@ static inline ssize_t do_tty_write( buf = kmalloc(chunk, GFP_KERNEL); if (!buf) { - up(&tty->atomic_write); + mutex_unlock(&tty->atomic_write_lock); return -ENOMEM; } kfree(tty->write_buf); @@ -1101,20 +1748,38 @@ static inline ssize_t do_tty_write( cond_resched(); } if (written) { - struct inode *inode = file->f_dentry->d_inode; + struct inode *inode = file->f_path.dentry->d_inode; inode->i_mtime = current_fs_time(inode->i_sb); ret = written; } - up(&tty->atomic_write); + 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; + struct inode *inode = file->f_path.dentry->d_inode; ssize_t ret; struct tty_ldisc *ld; @@ -1157,7 +1822,18 @@ ssize_t redirected_tty_write(struct file * file, const char __user * buf, size_t static char ptychar[] = "pqrstuvwxyzabcde"; -static inline void pty_line_name(struct tty_driver *driver, int index, char *p) +/** + * 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 */ @@ -1166,28 +1842,71 @@ static inline void pty_line_name(struct tty_driver *driver, int index, char *p) ptychar[i >> 4 & 0xf], i & 0xf); } -static inline void tty_line_name(struct tty_driver *driver, int index, char *p) +/** + * 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 semaphore, so it's - * really quite straightforward. The semaphore locking can probably be + * 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; + struct ktermios *tp, **tp_loc, *o_tp, **o_tp_loc; + struct ktermios *ltp, **ltp_loc, *o_ltp, **o_ltp_loc; + int retval = 0; /* check whether we're reopening an existing tty */ if (driver->flags & TTY_DRIVER_DEVPTS_MEM) { tty = devpts_get_tty(idx); + /* + * If we don't have a tty here on a slave open, it's because + * the master already started the close process and there's + * no relation between devpts file and tty anymore. + */ + if (!tty && driver->subtype == PTY_TYPE_SLAVE) { + retval = -EIO; + goto end_init; + } + /* + * It's safe from now on because init_dev() is called with + * tty_mutex held and release_dev() won't change tty->count + * or tty->flags without having to grab tty_mutex + */ if (tty && driver->subtype == PTY_TYPE_MASTER) tty = tty->link; } else { @@ -1229,7 +1948,7 @@ static int init_dev(struct tty_driver *driver, int idx, } if (!*tp_loc) { - tp = (struct termios *) kmalloc(sizeof(struct termios), + tp = (struct ktermios *) kmalloc(sizeof(struct ktermios), GFP_KERNEL); if (!tp) goto free_mem_out; @@ -1237,11 +1956,11 @@ static int init_dev(struct tty_driver *driver, int idx, } if (!*ltp_loc) { - ltp = (struct termios *) kmalloc(sizeof(struct termios), + ltp = (struct ktermios *) kmalloc(sizeof(struct ktermios), GFP_KERNEL); if (!ltp) goto free_mem_out; - memset(ltp, 0, sizeof(struct termios)); + memset(ltp, 0, sizeof(struct ktermios)); } if (driver->type == TTY_DRIVER_TYPE_PTY) { @@ -1262,19 +1981,19 @@ static int init_dev(struct tty_driver *driver, int idx, } if (!*o_tp_loc) { - o_tp = (struct termios *) - kmalloc(sizeof(struct termios), GFP_KERNEL); + o_tp = (struct ktermios *) + 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 = (struct termios *) - kmalloc(sizeof(struct termios), GFP_KERNEL); + o_ltp = (struct ktermios *) + kmalloc(sizeof(struct ktermios), GFP_KERNEL); if (!o_ltp) goto free_mem_out; - memset(o_ltp, 0, sizeof(struct termios)); + memset(o_ltp, 0, sizeof(struct ktermios)); } /* @@ -1313,6 +2032,9 @@ static int init_dev(struct tty_driver *driver, int idx, *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++; @@ -1371,20 +2093,17 @@ fast_track: success: *ret_tty = tty; - /* All paths come through here to release the semaphore */ + /* All paths come through here to release the mutex */ end_init: return retval; /* Release locally allocated memory ... nothing placed in slots */ free_mem_out: - if (o_tp) - kfree(o_tp); + kfree(o_tp); if (o_tty) free_tty_struct(o_tty); - if (ltp) - kfree(ltp); - if (tp) - kfree(tp); + kfree(ltp); + kfree(tp); free_tty_struct(tty); fail_no_mem: @@ -1394,20 +2113,31 @@ fail_no_mem: /* 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); + if (printk_ratelimit()) + printk(KERN_INFO "init_dev: ldisc open failed, " + "clearing slot %d\n", idx); release_mem(tty, idx); goto end_init; } -/* - * Releases memory associated with a tty structure, and clears out the - * driver table slots. +/** + * 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; + struct ktermios *tp; int devpts = tty->driver->flags & TTY_DRIVER_DEVPTS_MEM; if ((o_tty = tty->link) != NULL) { @@ -1467,13 +2197,13 @@ 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_master, devpts; + 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")) + if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "release_dev")) return; check_tty_count(tty, "release_dev"); @@ -1484,7 +2214,6 @@ static void release_dev(struct file * filp) pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY && tty->driver->subtype == PTY_TYPE_MASTER); devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0; - devpts_master = pty_master && devpts; o_tty = tty->link; #ifdef TTY_PARANOIA_CHECK @@ -1571,11 +2300,10 @@ static void release_dev(struct file * filp) /* Guard against races with tty->count changes elsewhere and opens on /dev/tty */ - down(&tty_sem); + mutex_lock(&tty_mutex); tty_closing = tty->count <= 1; o_tty_closing = o_tty && (o_tty->count <= (pty_master ? 1 : 0)); - up(&tty_sem); do_sleep = 0; if (tty_closing) { @@ -1603,6 +2331,7 @@ static void release_dev(struct file * filp) printk(KERN_WARNING "release_dev: %s: read/write wait queue " "active!\n", tty_name(tty, buf)); + mutex_unlock(&tty_mutex); schedule(); } @@ -1611,8 +2340,6 @@ static void release_dev(struct file * filp) * both sides, and we've completed the last operation that could * block, so it's safe to proceed with closing. */ - - down(&tty_sem); if (pty_master) { if (--o_tty->count < 0) { printk(KERN_WARNING "release_dev: bad pty slave count " @@ -1626,7 +2353,6 @@ static void release_dev(struct file * filp) tty->count, tty_name(tty, buf)); tty->count = 0; } - up(&tty_sem); /* * We've decremented tty->count, so we need to remove this file @@ -1658,19 +2384,15 @@ static void release_dev(struct file * filp) * 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); + session_clear_tty(tty->session); 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); + session_clear_tty(o_tty->session); read_unlock(&tasklist_lock); } + mutex_unlock(&tty_mutex); + /* check whether both sides are closing ... */ if (!tty_closing || (o_tty && !o_tty_closing)) return; @@ -1684,11 +2406,10 @@ static void release_dev(struct file * filp) * race with the set_ldisc code path. */ clear_bit(TTY_LDISC, &tty->flags); - clear_bit(TTY_DONT_FLIP, &tty->flags); - cancel_delayed_work(&tty->flip.work); + cancel_delayed_work(&tty->buf.work); /* - * Wait for ->hangup_work and ->flip.work handlers to terminate + * Wait for ->hangup_work and ->buf.work handlers to terminate */ flush_scheduled_work(); @@ -1747,18 +2468,27 @@ static void release_dev(struct file * filp) } -/* - * 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. +/** + * 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) + * 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. + * The termios state of a pty is reset on first open so that + * settings don't persist across reuse. + * + * Locking: tty_mutex protects tty, get_tty_driver and init_dev work. + * tty->count should protect the rest. + * ->siglock protects ->signal/->sighand */ + static int tty_open(struct inode * inode, struct file * filp) { struct tty_struct *tty; @@ -1775,15 +2505,16 @@ retry_open: index = -1; retval = 0; - down(&tty_sem); + mutex_lock(&tty_mutex); if (device == MKDEV(TTYAUX_MAJOR,0)) { - if (!current->signal->tty) { - up(&tty_sem); + tty = get_current_tty(); + if (!tty) { + mutex_unlock(&tty_mutex); return -ENXIO; } - driver = current->signal->tty->driver; - index = current->signal->tty->index; + driver = tty->driver; + index = tty->index; filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */ /* noctty = 1; */ goto got_driver; @@ -1805,18 +2536,18 @@ retry_open: noctty = 1; goto got_driver; } - up(&tty_sem); + mutex_unlock(&tty_mutex); return -ENODEV; } driver = get_tty_driver(device, &index); if (!driver) { - up(&tty_sem); + mutex_unlock(&tty_mutex); return -ENODEV; } got_driver: retval = init_dev(driver, index, &tty); - up(&tty_sem); + mutex_unlock(&tty_mutex); if (retval) return retval; @@ -1858,21 +2589,32 @@ got_driver: filp->f_op = &tty_fops; goto retry_open; } + + mutex_lock(&tty_mutex); + spin_lock_irq(¤t->sighand->siglock); if (!noctty && current->signal->leader && !current->signal->tty && - tty->session == 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); - } + tty->session == 0) + __proc_set_tty(current, tty); + spin_unlock_irq(¤t->sighand->siglock); + mutex_unlock(&tty_mutex); 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; @@ -1902,9 +2644,9 @@ static int ptmx_open(struct inode * inode, struct file * filp) } up(&allocated_ptys_lock); - down(&tty_sem); + mutex_lock(&tty_mutex); retval = init_dev(ptm_driver, index, &tty); - up(&tty_sem); + mutex_unlock(&tty_mutex); if (retval) goto out; @@ -1923,6 +2665,7 @@ static int ptmx_open(struct inode * inode, struct file * filp) return 0; out1: release_dev(filp); + return retval; out: down(&allocated_ptys_lock); idr_remove(&allocated_ptys, index); @@ -1931,6 +2674,18 @@ out: } #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(); @@ -1939,7 +2694,18 @@ static int tty_release(struct inode * inode, struct file * filp) return 0; } -/* No kernel lock held - fine */ +/** + * 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; @@ -1947,7 +2713,7 @@ static unsigned int tty_poll(struct file * filp, poll_table * wait) int ret = 0; tty = (struct tty_struct *)filp->private_data; - if (tty_paranoia_check(tty, filp->f_dentry->d_inode, "tty_poll")) + if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll")) return 0; ld = tty_ldisc_ref_wait(tty); @@ -1963,7 +2729,7 @@ static int tty_fasync(int fd, struct file * filp, int on) int retval; tty = (struct tty_struct *)filp->private_data; - if (tty_paranoia_check(tty, filp->f_dentry->d_inode, "tty_fasync")) + if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync")) return 0; retval = fasync_helper(fd, filp, on, &tty->fasync); @@ -1983,6 +2749,23 @@ static int tty_fasync(int fd, struct file * filp, int on) 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 + * + * FIXME: may race normal receive processing + */ + static int tiocsti(struct tty_struct *tty, char __user *p) { char ch, mbz = 0; @@ -1998,13 +2781,45 @@ static int tiocsti(struct tty_struct *tty, char __user *p) return 0; } +/** + * tiocgwinsz - implement window query ioctl + * @tty; tty + * @arg: user buffer for result + * + * Copies the kernel idea of the window size into the user buffer. + * + * Locking: tty->termios_mutex is taken to ensure the winsize data + * is consistent. + */ + static int tiocgwinsz(struct tty_struct *tty, struct winsize __user * arg) { - if (copy_to_user(arg, &tty->winsize, sizeof(*arg))) - return -EFAULT; - return 0; + int err; + + mutex_lock(&tty->termios_mutex); + err = copy_to_user(arg, &tty->winsize, sizeof(*arg)); + mutex_unlock(&tty->termios_mutex); + + return err ? -EFAULT: 0; } +/** + * 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: + * Called function use the console_sem is used to ensure we do + * not try and resize the console twice at once. + * The tty->termios_mutex is used to ensure we don't double + * resize and get confused. Lock order - tty->termios_mutex before + * console sem + */ + static int tiocswinsz(struct tty_struct *tty, struct tty_struct *real_tty, struct winsize __user * arg) { @@ -2012,17 +2827,18 @@ static int tiocswinsz(struct tty_struct *tty, struct tty_struct *real_tty, if (copy_from_user(&tmp_ws, arg, sizeof(*arg))) return -EFAULT; + + mutex_lock(&tty->termios_mutex); if (!memcmp(&tmp_ws, &tty->winsize, sizeof(*arg))) - return 0; + goto done; + #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; + if (vc_lock_resize(tty->driver_data, tmp_ws.ws_col, + tmp_ws.ws_row)) { + mutex_unlock(&tty->termios_mutex); + return -ENXIO; + } } #endif if (tty->pgrp > 0) @@ -2031,9 +2847,20 @@ static int tiocswinsz(struct tty_struct *tty, struct tty_struct *real_tty, kill_pg(real_tty->pgrp, SIGWINCH, 1); tty->winsize = tmp_ws; real_tty->winsize = tmp_ws; +done: + mutex_unlock(&tty->termios_mutex); 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)) @@ -2059,6 +2886,17 @@ static int tioccons(struct file *file) 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) { @@ -2074,19 +2912,37 @@ static int fionbio(struct file *file, int __user *p) return 0; } +/** + * tiocsctty - set controlling tty + * @tty: tty structure + * @arg: user argument + * + * This ioctl is used to manage job control. It permits a session + * leader to set this tty as the controlling tty for the session. + * + * Locking: + * Takes tty_mutex() to protect tty instance + * Takes tasklist_lock internally to walk sessions + * Takes ->siglock() when updating signal->tty + */ + static int tiocsctty(struct tty_struct *tty, int arg) { - task_t *p; - + int ret = 0; if (current->signal->leader && - (current->signal->session == tty->session)) - return 0; + (process_session(current) == tty->session)) + return ret; + + mutex_lock(&tty_mutex); /* * The process must be a session leader and * not have a controlling tty already. */ - if (!current->signal->leader || current->signal->tty) - return -EPERM; + if (!current->signal->leader || current->signal->tty) { + ret = -EPERM; + goto unlock; + } + if (tty->session > 0) { /* * This tty is already the controlling @@ -2096,24 +2952,32 @@ static int tiocsctty(struct tty_struct *tty, int arg) /* * 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); + session_clear_tty(tty->session); read_unlock(&tasklist_lock); - } else - return -EPERM; + } else { + ret = -EPERM; + goto unlock; + } } - 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; + proc_set_tty(current, tty); +unlock: + mutex_unlock(&tty_mutex); + return ret; } +/** + * tiocgpgrp - get process group + * @tty: tty passed by user + * @real_tty: tty side of the tty pased by the user if a pty else the tty + * @p: returned pid + * + * Obtain the process group of the tty. If there is no process group + * return an error. + * + * Locking: none. Reference to current->signal->tty is safe. + */ + static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) { pid_t pgrp; @@ -2128,6 +2992,18 @@ static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t return put_user(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 + */ + static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) { pid_t pgrp; @@ -2139,7 +3015,7 @@ static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t return retval; if (!current->signal->tty || (current->signal->tty != real_tty) || - (real_tty->session != current->signal->session)) + (real_tty->session != process_session(current))) return -ENOTTY; if (get_user(pgrp, p)) return -EFAULT; @@ -2147,12 +3023,24 @@ static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t pgrp = vx_rmap_pid(pgrp); if (pgrp < 0) return -EINVAL; - if (session_of_pgrp(pgrp) != current->signal->session) + if (session_of_pgrp(pgrp) != process_session(current)) 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 current->signal->tty is safe. + */ + static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) { /* @@ -2166,6 +3054,16 @@ static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t _ 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; @@ -2175,21 +3073,47 @@ static int tiocsetd(struct tty_struct *tty, int __user *p) return tty_set_ldisc(tty, ldisc); } -static int send_break(struct tty_struct *tty, int duration) +/** + * send_break - performed time break + * @tty: device to break on + * @duration: timeout in mS + * + * Perform a timed break on hardware that lacks its own driver level + * timed break functionality. + * + * Locking: + * atomic_write_lock serializes + * + */ + +static int send_break(struct tty_struct *tty, unsigned int duration) { + if (mutex_lock_interruptible(&tty->atomic_write_lock)) + return -EINTR; tty->driver->break_ctl(tty, -1); if (!signal_pending(current)) { - set_current_state(TASK_INTERRUPTIBLE); - schedule_timeout(duration); + msleep_interruptible(duration); } tty->driver->break_ctl(tty, 0); + mutex_unlock(&tty->atomic_write_lock); if (signal_pending(current)) return -EINTR; return 0; } -static int -tty_tiocmget(struct tty_struct *tty, struct file *file, int __user *p) +/** + * 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; @@ -2202,8 +3126,20 @@ tty_tiocmget(struct tty_struct *tty, struct file *file, int __user *p) return retval; } -static int -tty_tiocmset(struct tty_struct *tty, struct file *file, unsigned int cmd, +/** + * 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; @@ -2252,6 +3188,8 @@ int tty_ioctl(struct inode * inode, struct file * file, if (tty_paranoia_check(tty, inode, "tty_ioctl")) return -EINVAL; + /* CHECKME: is this safe as one end closes ? */ + real_tty = tty; if (tty->driver->type == TTY_DRIVER_TYPE_PTY && tty->driver->subtype == PTY_TYPE_MASTER) @@ -2323,9 +3261,7 @@ int tty_ioctl(struct inode * inode, struct file * file, return -ENOTTY; if (current->signal->leader) disassociate_ctty(0); - task_lock(current); - current->signal->tty = NULL; - task_unlock(current); + proc_clear_tty(current); return 0; case TIOCSCTTY: return tiocsctty(tty, arg); @@ -2355,16 +3291,15 @@ int tty_ioctl(struct inode * inode, struct file * file, tty->driver->break_ctl(tty, 0); return 0; case TCSBRK: /* SVID version: non-zero arg --> no break */ - /* - * XXX is the above comment correct, or the - * code below correct? Is this ioctl used at - * all by anyone? + /* 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, HZ/4); + return send_break(tty, 250); return 0; case TCSBRKP: /* support for POSIX tcsendbreak() */ - return send_break(tty, arg ? arg*(HZ/10) : HZ/4); + return send_break(tty, arg ? arg*100 : 250); case TIOCMGET: return tty_tiocmget(tty, file, p); @@ -2410,44 +3345,56 @@ int tty_ioctl(struct inode * inode, struct file * file, * 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) +static void __do_SAK(struct work_struct *work) { + struct tty_struct *tty = + container_of(work, struct tty_struct, SAK_work); #ifdef TTY_SOFT_SAK tty_hangup(tty); #else - struct tty_struct *tty = arg; - struct task_struct *p; + 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; + 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); + tty_ldisc_flush(tty); 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) { - if (p->signal->tty == tty || session > 0) { + printk(KERN_NOTICE "SAK: killed process %d" + " (%s): process_session(p)==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", + " (%s): process_session(p)==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); - for (i=0; i < p->files->max_fds; i++) { + fdt = files_fdtable(p->files); + for (i=0; i < fdt->max_fds; i++) { filp = fcheck_files(p->files, i); if (!filp) continue; @@ -2456,14 +3403,14 @@ static void __do_SAK(void *arg) printk(KERN_NOTICE "SAK: killed process %d" " (%s): fd#%d opened to the tty\n", p->pid, p->comm, i); - send_sig(SIGKILL, p, 1); + force_sig(SIGKILL, p); break; } } spin_unlock(&p->files->file_lock); } task_unlock(p); - } while_each_task_pid(session, PIDTYPE_SID, p); + } while_each_thread(g, p); read_unlock(&tasklist_lock); #endif } @@ -2478,134 +3425,72 @@ void do_SAK(struct tty_struct *tty) { if (!tty) return; - PREPARE_WORK(&tty->SAK_work, __do_SAK, tty); + PREPARE_WORK(&tty->SAK_work, __do_SAK); schedule_work(&tty->SAK_work); } EXPORT_SYMBOL(do_SAK); -/* - * This routine is called out of the software interrupt to flush data - * from the flip buffer to the line discipline. +/** + * flush_to_ldisc + * @work: 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_) +static void flush_to_ldisc(struct work_struct *work) { - struct tty_struct *tty = (struct tty_struct *) private_; - unsigned char *cp; - char *fp; - int count; + struct tty_struct *tty = + container_of(work, struct tty_struct, buf.work.work); 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; - if (test_bit(TTY_DONT_FLIP, &tty->flags)) { - /* - * Do it after the next timer tick: - */ - schedule_delayed_work(&tty->flip.work, 1); - goto out; - } - spin_lock_irqsave(&tty->read_lock, flags); - if (tty->flip.buf_num) { - cp = tty->flip.char_buf + TTY_FLIPBUF_SIZE; - fp = tty->flip.flag_buf + TTY_FLIPBUF_SIZE; - tty->flip.buf_num = 0; - tty->flip.char_buf_ptr = tty->flip.char_buf; - tty->flip.flag_buf_ptr = tty->flip.flag_buf; - } else { - cp = tty->flip.char_buf; - fp = tty->flip.flag_buf; - tty->flip.buf_num = 1; - tty->flip.char_buf_ptr = tty->flip.char_buf + TTY_FLIPBUF_SIZE; - tty->flip.flag_buf_ptr = tty->flip.flag_buf + TTY_FLIPBUF_SIZE; + 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; } - count = tty->flip.count; - tty->flip.count = 0; - spin_unlock_irqrestore(&tty->read_lock, flags); + spin_unlock_irqrestore(&tty->buf.lock, flags); - disc->receive_buf(tty, cp, fp, count); -out: 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. - */ - -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. - */ - -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 @@ -2615,21 +3500,37 @@ EXPORT_SYMBOL(tty_get_baud_rate); * * 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); + flush_to_ldisc(&tty->buf.work.work); else - schedule_delayed_work(&tty->flip.work, 1); + schedule_delayed_work(&tty->buf.work, 1); } EXPORT_SYMBOL(tty_flip_buffer_push); -/* - * This subroutine initializes a tty structure. + +/** + * 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)); @@ -2637,45 +3538,53 @@ static void initialize_tty_struct(struct tty_struct *tty) tty_ldisc_assign(tty, tty_ldisc_get(N_TTY)); tty->pgrp = -1; tty->overrun_time = jiffies; - tty->flip.char_buf_ptr = tty->flip.char_buf; - tty->flip.flag_buf_ptr = tty->flip.flag_buf; - INIT_WORK(&tty->flip.work, flush_to_ldisc, tty); - init_MUTEX(&tty->flip.pty_sem); - init_MUTEX(&tty->termios_sem); + tty->buf.head = tty->buf.tail = NULL; + tty_buffer_init(tty); + INIT_DELAYED_WORK(&tty->buf.work, flush_to_ldisc); + init_MUTEX(&tty->buf.pty_sem); + mutex_init(&tty->termios_mutex); init_waitqueue_head(&tty->write_wait); init_waitqueue_head(&tty->read_wait); - INIT_WORK(&tty->hangup_work, do_tty_hangup, tty); - sema_init(&tty->atomic_read, 1); - sema_init(&tty->atomic_write, 1); + INIT_WORK(&tty->hangup_work, do_tty_hangup); + mutex_init(&tty->atomic_read_lock); + mutex_init(&tty->atomic_write_lock); spin_lock_init(&tty->read_lock); INIT_LIST_HEAD(&tty->tty_files); - INIT_WORK(&tty->SAK_work, NULL, NULL); + INIT_WORK(&tty->SAK_work, 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_simple *tty_class; +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. + * tty_register_device - register a tty device + * @driver: the tty driver that describes the tty device + * @index: the index in the tty driver for this tty device + * @device: a struct device that is associated with this tty device. + * This field is optional, if there is no known struct device + * for this tty device it can be set to NULL safely. + * + * Returns a pointer to the struct device for this tty device + * (or ERR_PTR(-EFOO) on error). * - * This call is required to be made to register an individual tty device if - * the tty driver's flags have the TTY_DRIVER_NO_DEVFS bit set. If that - * bit is not set, this function should not be called. + * 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: ?? */ -void tty_register_device(struct tty_driver *driver, unsigned index, - struct device *device) + +struct device *tty_register_device(struct tty_driver *driver, unsigned index, + struct device *device) { char name[64]; dev_t dev = MKDEV(driver->major, driver->minor_start) + index; @@ -2683,31 +3592,31 @@ void tty_register_device(struct tty_driver *driver, unsigned index, if (index >= driver->num) { printk(KERN_ERR "Attempt to register invalid tty line number " " (%d).\n", index); - return; + return ERR_PTR(-EINVAL); } - devfs_mk_cdev(dev, S_IFCHR | S_IRUSR | S_IWUSR, - "%s%d", driver->devfs_name, index + driver->name_base); - if (driver->type == TTY_DRIVER_TYPE_PTY) pty_line_name(driver, index, name); else tty_line_name(driver, index, name); - class_simple_device_add(tty_class, dev, device, name); + + return device_create(tty_class, device, dev, 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 + * 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. * - * If a tty device is registered with a call to tty_register_device() then - * this function must be made when the tty device is gone. + * Locking: ?? */ + void tty_unregister_device(struct tty_driver *driver, unsigned index) { - devfs_remove("%s%d", driver->devfs_name, index + driver->name_base); - class_simple_device_remove(MKDEV(driver->major, driver->minor_start) + index); + device_destroy(tty_class, MKDEV(driver->major, driver->minor_start) + index); } EXPORT_SYMBOL(tty_register_device); @@ -2732,7 +3641,8 @@ void put_tty_driver(struct tty_driver *driver) kfree(driver); } -void tty_set_operations(struct tty_driver *driver, struct tty_operations *op) +void tty_set_operations(struct tty_driver *driver, + const struct tty_operations *op) { driver->open = op->open; driver->close = op->close; @@ -2803,8 +3713,8 @@ int tty_register_driver(struct tty_driver *driver) if (p) { driver->ttys = (struct tty_struct **)p; - driver->termios = (struct termios **)(p + driver->num); - driver->termios_locked = (struct termios **)(p + driver->num * 2); + driver->termios = (struct ktermios **)(p + driver->num); + driver->termios_locked = (struct ktermios **)(p + driver->num * 2); } else { driver->ttys = NULL; driver->termios = NULL; @@ -2815,7 +3725,6 @@ int tty_register_driver(struct tty_driver *driver) driver->cdev.owner = driver->owner; error = cdev_add(&driver->cdev, dev, driver->num); if (error) { - cdev_del(&driver->cdev); unregister_chrdev_region(dev, driver->num); driver->ttys = NULL; driver->termios = driver->termios_locked = NULL; @@ -2828,7 +3737,7 @@ int tty_register_driver(struct tty_driver *driver) list_add(&driver->tty_drivers, &tty_drivers); - if ( !(driver->flags & TTY_DRIVER_NO_DEVFS) ) { + if ( !(driver->flags & TTY_DRIVER_DYNAMIC_DEV) ) { for(i = 0; i < driver->num; i++) tty_register_device(driver, i, NULL); } @@ -2844,7 +3753,7 @@ EXPORT_SYMBOL(tty_register_driver); int tty_unregister_driver(struct tty_driver *driver) { int i; - struct termios *tp; + struct ktermios *tp; void *p; if (driver->refcount) @@ -2871,7 +3780,7 @@ int tty_unregister_driver(struct tty_driver *driver) driver->termios_locked[i] = NULL; kfree(tp); } - if (!(driver->flags & TTY_DRIVER_NO_DEVFS)) + if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) tty_unregister_device(driver, i); } p = driver->ttys; @@ -2882,9 +3791,56 @@ int tty_unregister_driver(struct tty_driver *driver) cdev_del(&driver->cdev); return 0; } - EXPORT_SYMBOL(tty_unregister_driver); +dev_t tty_devnum(struct tty_struct *tty) +{ + WARN_ON(!tty); + WARN_ON(!tty->magic); + WARN_ON(!tty->driver); + return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index; +} +EXPORT_SYMBOL(tty_devnum); + +void proc_clear_tty(struct task_struct *p) +{ + spin_lock_irq(&p->sighand->siglock); + p->signal->tty = NULL; + spin_unlock_irq(&p->sighand->siglock); +} +EXPORT_SYMBOL(proc_clear_tty); + +void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty) +{ + if (tty) { + tty->session = process_session(tsk); + tty->pgrp = process_group(tsk); + } + tsk->signal->tty = tty; + tsk->signal->tty_old_pgrp = 0; +} + +void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty) +{ + spin_lock_irq(&tsk->sighand->siglock); + __proc_set_tty(tsk, tty); + spin_unlock_irq(&tsk->sighand->siglock); +} + +struct tty_struct *get_current_tty(void) +{ + struct tty_struct *tty; + WARN_ON_ONCE(!mutex_is_locked(&tty_mutex)); + tty = current->signal->tty; + /* + * session->tty can be changed/cleared from under us, make sure we + * issue the load. The obtained pointer, when not NULL, is valid as + * long as we hold tty_mutex. + */ + barrier(); + return tty; +} +EXPORT_SYMBOL_GPL(get_current_tty); /* * Initialize the console device. This is called *early*, so @@ -2905,11 +3861,6 @@ void __init console_init(void) */ #ifdef CONFIG_EARLY_PRINTK disable_early_printk(); -#endif -#ifdef CONFIG_SERIAL_68360 - /* This is not a console initcall. I know not what it's doing here. - So I haven't moved it. dwmw2 */ - rs_360_init(); #endif call = __con_initcall_start; while (call < __con_initcall_end) { @@ -2924,7 +3875,7 @@ extern int vty_init(void); static int __init tty_class_init(void) { - tty_class = class_simple_create(THIS_MODULE, "tty"); + tty_class = class_create(THIS_MODULE, "tty"); if (IS_ERR(tty_class)) return PTR_ERR(tty_class); return 0; @@ -2952,23 +3903,20 @@ static int __init tty_init(void) 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"); - devfs_mk_cdev(MKDEV(TTYAUX_MAJOR, 0), S_IFCHR|S_IRUGO|S_IWUGO, "tty"); - class_simple_device_add(tty_class, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty"); + device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), "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"); - devfs_mk_cdev(MKDEV(TTYAUX_MAJOR, 1), S_IFCHR|S_IRUSR|S_IWUSR, "console"); - class_simple_device_add(tty_class, MKDEV(TTYAUX_MAJOR, 1), NULL, "console"); + device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), "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"); - devfs_mk_cdev(MKDEV(TTYAUX_MAJOR, 2), S_IFCHR|S_IRUGO|S_IWUGO, "ptmx"); - class_simple_device_add(tty_class, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx"); + device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), "ptmx"); #endif #ifdef CONFIG_VT @@ -2976,10 +3924,10 @@ static int __init tty_init(void) 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"); - devfs_mk_cdev(MKDEV(TTY_MAJOR, 0), S_IFCHR|S_IRUSR|S_IWUSR, "vc/0"); - class_simple_device_add(tty_class, MKDEV(TTY_MAJOR, 0), NULL, "tty0"); + device_create(tty_class, NULL, MKDEV(TTY_MAJOR, 0), "tty0"); vty_init(); + out_vt: #endif return 0; }