[deliverable/linux.git] / drivers / char / vc_screen.c

/*
 * linux/drivers/char/vc_screen.c
 *
 * Provide access to virtual console memory.
 * /dev/vcs0: the screen as it is being viewed right now (possibly scrolled)
 * /dev/vcsN: the screen of /dev/ttyN (1 <= N <= 63)
 *            [minor: N]
 *
 * /dev/vcsaN: idem, but including attributes, and prefixed with
 *	the 4 bytes lines,columns,x,y (as screendump used to give).
 *	Attribute/character pair is in native endianity.
 *            [minor: N+128]
 *
 * This replaces screendump and part of selection, so that the system
 * administrator can control access using file system permissions.
 *
 * aeb@cwi.nl - efter Friedas begravelse - 950211
 *
 * machek@k332.feld.cvut.cz - modified not to send characters to wrong console
 *	 - fixed some fatal off-by-one bugs (0-- no longer == -1 -> looping and looping and looping...)
 *	 - making it shorter - scr_readw are macros which expand in PRETTY long code
 */

#include <linux/kernel.h>
#include <linux/major.h>
#include <linux/errno.h>
#include <linux/tty.h>
#include <linux/interrupt.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/mutex.h>
#include <linux/vt_kern.h>
#include <linux/selection.h>
#include <linux/kbd_kern.h>
#include <linux/console.h>
#include <linux/device.h>
#include <linux/smp_lock.h>
#include <linux/sched.h>
#include <linux/fs.h>
#include <linux/poll.h>
#include <linux/signal.h>
#include <linux/slab.h>
#include <linux/notifier.h>

#include <asm/uaccess.h>
#include <asm/byteorder.h>
#include <asm/unaligned.h>

#undef attr
#undef org
#undef addr
#define HEADER_SIZE	4

struct vcs_poll_data {
	struct notifier_block notifier;
	unsigned int cons_num;
	bool seen_last_update;
	wait_queue_head_t waitq;
	struct fasync_struct *fasync;
};

static int
vcs_notifier(struct notifier_block *nb, unsigned long code, void *_param)
{
	struct vt_notifier_param *param = _param;
	struct vc_data *vc = param->vc;
	struct vcs_poll_data *poll =
		container_of(nb, struct vcs_poll_data, notifier);
	int currcons = poll->cons_num;

	if (code != VT_UPDATE)
		return NOTIFY_DONE;

	if (currcons == 0)
		currcons = fg_console;
	else
		currcons--;
	if (currcons != vc->vc_num)
		return NOTIFY_DONE;

	poll->seen_last_update = false;
	wake_up_interruptible(&poll->waitq);
	kill_fasync(&poll->fasync, SIGIO, POLL_IN);
	return NOTIFY_OK;
}

static void
vcs_poll_data_free(struct vcs_poll_data *poll)
{
	unregister_vt_notifier(&poll->notifier);
	kfree(poll);
}

static struct vcs_poll_data *
vcs_poll_data_get(struct file *file)
{
	struct vcs_poll_data *poll = file->private_data;

	if (poll)
		return poll;

	poll = kzalloc(sizeof(*poll), GFP_KERNEL);
	if (!poll)
		return NULL;
	poll->cons_num = iminor(file->f_path.dentry->d_inode) & 127;
	init_waitqueue_head(&poll->waitq);
	poll->notifier.notifier_call = vcs_notifier;
	if (register_vt_notifier(&poll->notifier) != 0) {
		kfree(poll);
		return NULL;
	}

	/*
	 * This code may be called either through ->poll() or ->fasync().
	 * If we have two threads using the same file descriptor, they could
	 * both enter this function, both notice that the structure hasn't
	 * been allocated yet and go ahead allocating it in parallel, but
	 * only one of them must survive and be shared otherwise we'd leak
	 * memory with a dangling notifier callback.
	 */
	spin_lock(&file->f_lock);
	if (!file->private_data) {
		file->private_data = poll;
	} else {
		/* someone else raced ahead of us */
		vcs_poll_data_free(poll);
		poll = file->private_data;
	}
	spin_unlock(&file->f_lock);

	return poll;
}

static int
vcs_size(struct inode *inode)
{
	int size;
	int minor = iminor(inode);
	int currcons = minor & 127;
	struct vc_data *vc;

	if (currcons == 0)
		currcons = fg_console;
	else
		currcons--;
	if (!vc_cons_allocated(currcons))
		return -ENXIO;
	vc = vc_cons[currcons].d;

	size = vc->vc_rows * vc->vc_cols;

	if (minor & 128)
		size = 2*size + HEADER_SIZE;
	return size;
}

static loff_t vcs_lseek(struct file *file, loff_t offset, int orig)
{
	int size;

	mutex_lock(&con_buf_mtx);
	size = vcs_size(file->f_path.dentry->d_inode);
	switch (orig) {
		default:
			mutex_unlock(&con_buf_mtx);
			return -EINVAL;
		case 2:
			offset += size;
			break;
		case 1:
			offset += file->f_pos;
		case 0:
			break;
	}
	if (offset < 0 || offset > size) {
		mutex_unlock(&con_buf_mtx);
		return -EINVAL;
	}
	file->f_pos = offset;
	mutex_unlock(&con_buf_mtx);
	return file->f_pos;
}


static ssize_t
vcs_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
	struct inode *inode = file->f_path.dentry->d_inode;
	unsigned int currcons = iminor(inode);
	struct vc_data *vc;
	struct vcs_poll_data *poll;
	long pos;
	long viewed, attr, read;
	int col, maxcol;
	unsigned short *org = NULL;
	ssize_t ret;

	mutex_lock(&con_buf_mtx);

	pos = *ppos;

	/* Select the proper current console and verify
	 * sanity of the situation under the console lock.
	 */
	acquire_console_sem();

	attr = (currcons & 128);
	currcons = (currcons & 127);
	if (currcons == 0) {
		currcons = fg_console;
		viewed = 1;
	} else {
		currcons--;
		viewed = 0;
	}
	ret = -ENXIO;
	if (!vc_cons_allocated(currcons))
		goto unlock_out;
	vc = vc_cons[currcons].d;

	ret = -EINVAL;
	if (pos < 0)
		goto unlock_out;
	poll = file->private_data;
	if (count && poll)
		poll->seen_last_update = true;
	read = 0;
	ret = 0;
	while (count) {
		char *con_buf0, *con_buf_start;
		long this_round, size;
		ssize_t orig_count;
		long p = pos;

		/* Check whether we are above size each round,
		 * as copy_to_user at the end of this loop
		 * could sleep.
		 */
		size = vcs_size(inode);
		if (pos >= size)
			break;
		if (count > size - pos)
			count = size - pos;

		this_round = count;
		if (this_round > CON_BUF_SIZE)
			this_round = CON_BUF_SIZE;

		/* Perform the whole read into the local con_buf.
		 * Then we can drop the console spinlock and safely
		 * attempt to move it to userspace.
		 */

		con_buf_start = con_buf0 = con_buf;
		orig_count = this_round;
		maxcol = vc->vc_cols;
		if (!attr) {
			org = screen_pos(vc, p, viewed);
			col = p % maxcol;
			p += maxcol - col;
			while (this_round-- > 0) {
				*con_buf0++ = (vcs_scr_readw(vc, org++) & 0xff);
				if (++col == maxcol) {
					org = screen_pos(vc, p, viewed);
					col = 0;
					p += maxcol;
				}
			}
		} else {
			if (p < HEADER_SIZE) {
				size_t tmp_count;

				con_buf0[0] = (char)vc->vc_rows;
				con_buf0[1] = (char)vc->vc_cols;
				getconsxy(vc, con_buf0 + 2);

				con_buf_start += p;
				this_round += p;
				if (this_round > CON_BUF_SIZE) {
					this_round = CON_BUF_SIZE;
					orig_count = this_round - p;
				}

				tmp_count = HEADER_SIZE;
				if (tmp_count > this_round)
					tmp_count = this_round;

				/* Advance state pointers and move on. */
				this_round -= tmp_count;
				p = HEADER_SIZE;
				con_buf0 = con_buf + HEADER_SIZE;
				/* If this_round >= 0, then p is even... */
			} else if (p & 1) {
				/* Skip first byte for output if start address is odd
				 * Update region sizes up/down depending on free
				 * space in buffer.
				 */
				con_buf_start++;
				if (this_round < CON_BUF_SIZE)
					this_round++;
				else
					orig_count--;
			}
			if (this_round > 0) {
				unsigned short *tmp_buf = (unsigned short *)con_buf0;

				p -= HEADER_SIZE;
				p /= 2;
				col = p % maxcol;

				org = screen_pos(vc, p, viewed);
				p += maxcol - col;

				/* Buffer has even length, so we can always copy
				 * character + attribute. We do not copy last byte
				 * to userspace if this_round is odd.
				 */
				this_round = (this_round + 1) >> 1;

				while (this_round) {
					*tmp_buf++ = vcs_scr_readw(vc, org++);
					this_round --;
					if (++col == maxcol) {
						org = screen_pos(vc, p, viewed);
						col = 0;
						p += maxcol;
					}
				}
			}
		}

		/* Finally, release the console semaphore while we push
		 * all the data to userspace from our temporary buffer.
		 *
		 * AKPM: Even though it's a semaphore, we should drop it because
		 * the pagefault handling code may want to call printk().
		 */

		release_console_sem();
		ret = copy_to_user(buf, con_buf_start, orig_count);
		acquire_console_sem();

		if (ret) {
			read += (orig_count - ret);
			ret = -EFAULT;
			break;
		}
		buf += orig_count;
		pos += orig_count;
		read += orig_count;
		count -= orig_count;
	}
	*ppos += read;
	if (read)
		ret = read;
unlock_out:
	release_console_sem();
	mutex_unlock(&con_buf_mtx);
	return ret;
}

static ssize_t
vcs_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
{
	struct inode *inode = file->f_path.dentry->d_inode;
	unsigned int currcons = iminor(inode);
	struct vc_data *vc;
	long pos;
	long viewed, attr, size, written;
	char *con_buf0;
	int col, maxcol;
	u16 *org0 = NULL, *org = NULL;
	size_t ret;

	mutex_lock(&con_buf_mtx);

	pos = *ppos;

	/* Select the proper current console and verify
	 * sanity of the situation under the console lock.
	 */
	acquire_console_sem();

	attr = (currcons & 128);
	currcons = (currcons & 127);

	if (currcons == 0) {
		currcons = fg_console;
		viewed = 1;
	} else {
		currcons--;
		viewed = 0;
	}
	ret = -ENXIO;
	if (!vc_cons_allocated(currcons))
		goto unlock_out;
	vc = vc_cons[currcons].d;

	size = vcs_size(inode);
	ret = -EINVAL;
	if (pos < 0 || pos > size)
		goto unlock_out;
	if (count > size - pos)
		count = size - pos;
	written = 0;
	while (count) {
		long this_round = count;
		size_t orig_count;
		long p;

		if (this_round > CON_BUF_SIZE)
			this_round = CON_BUF_SIZE;

		/* Temporarily drop the console lock so that we can read
		 * in the write data from userspace safely.
		 */
		release_console_sem();
		ret = copy_from_user(con_buf, buf, this_round);
		acquire_console_sem();

		if (ret) {
			this_round -= ret;
			if (!this_round) {
				/* Abort loop if no data were copied. Otherwise
				 * fail with -EFAULT.
				 */
				if (written)
					break;
				ret = -EFAULT;
				goto unlock_out;
			}
		}

		/* The vcs_size might have changed while we slept to grab
		 * the user buffer, so recheck.
		 * Return data written up to now on failure.
		 */
		size = vcs_size(inode);
		if (pos >= size)
			break;
		if (this_round > size - pos)
			this_round = size - pos;

		/* OK, now actually push the write to the console
		 * under the lock using the local kernel buffer.
		 */

		con_buf0 = con_buf;
		orig_count = this_round;
		maxcol = vc->vc_cols;
		p = pos;
		if (!attr) {
			org0 = org = screen_pos(vc, p, viewed);
			col = p % maxcol;
			p += maxcol - col;

			while (this_round > 0) {
				unsigned char c = *con_buf0++;

				this_round--;
				vcs_scr_writew(vc,
					       (vcs_scr_readw(vc, org) & 0xff00) | c, org);
				org++;
				if (++col == maxcol) {
					org = screen_pos(vc, p, viewed);
					col = 0;
					p += maxcol;
				}
			}
		} else {
			if (p < HEADER_SIZE) {
				char header[HEADER_SIZE];

				getconsxy(vc, header + 2);
				while (p < HEADER_SIZE && this_round > 0) {
					this_round--;
					header[p++] = *con_buf0++;
				}
				if (!viewed)
					putconsxy(vc, header + 2);
			}
			p -= HEADER_SIZE;
			col = (p/2) % maxcol;
			if (this_round > 0) {
				org0 = org = screen_pos(vc, p/2, viewed);
				if ((p & 1) && this_round > 0) {
					char c;

					this_round--;
					c = *con_buf0++;
#ifdef __BIG_ENDIAN
					vcs_scr_writew(vc, c |
					     (vcs_scr_readw(vc, org) & 0xff00), org);
#else
					vcs_scr_writew(vc, (c << 8) |
					     (vcs_scr_readw(vc, org) & 0xff), org);
#endif
					org++;
					p++;
					if (++col == maxcol) {
						org = screen_pos(vc, p/2, viewed);
						col = 0;
					}
				}
				p /= 2;
				p += maxcol - col;
			}
			while (this_round > 1) {
				unsigned short w;

				w = get_unaligned(((unsigned short *)con_buf0));
				vcs_scr_writew(vc, w, org++);
				con_buf0 += 2;
				this_round -= 2;
				if (++col == maxcol) {
					org = screen_pos(vc, p, viewed);
					col = 0;
					p += maxcol;
				}
			}
			if (this_round > 0) {
				unsigned char c;

				c = *con_buf0++;
#ifdef __BIG_ENDIAN
				vcs_scr_writew(vc, (vcs_scr_readw(vc, org) & 0xff) | (c << 8), org);
#else
				vcs_scr_writew(vc, (vcs_scr_readw(vc, org) & 0xff00) | c, org);
#endif
			}
		}
		count -= orig_count;
		written += orig_count;
		buf += orig_count;
		pos += orig_count;
		if (org0)
			update_region(vc, (unsigned long)(org0), org - org0);
	}
	*ppos += written;
	ret = written;
	if (written)
		vcs_scr_updated(vc);

unlock_out:
	release_console_sem();

	mutex_unlock(&con_buf_mtx);

	return ret;
}

static unsigned int
vcs_poll(struct file *file, poll_table *wait)
{
	struct vcs_poll_data *poll = vcs_poll_data_get(file);
	int ret = 0;

	if (poll) {
		poll_wait(file, &poll->waitq, wait);
		if (!poll->seen_last_update)
			ret = POLLIN | POLLRDNORM;
	}
	return ret;
}

static int
vcs_fasync(int fd, struct file *file, int on)
{
	struct vcs_poll_data *poll = file->private_data;

	if (!poll) {
		/* don't allocate anything if all we want is disable fasync */
		if (!on)
			return 0;
		poll = vcs_poll_data_get(file);
		if (!poll)
			return -ENOMEM;
	}

	return fasync_helper(fd, file, on, &poll->fasync);
}

static int
vcs_open(struct inode *inode, struct file *filp)
{
	unsigned int currcons = iminor(inode) & 127;
	int ret = 0;
	
	tty_lock();
	if(currcons && !vc_cons_allocated(currcons-1))
		ret = -ENXIO;
	tty_unlock();
	return ret;
}

static int vcs_release(struct inode *inode, struct file *file)
{
	struct vcs_poll_data *poll = file->private_data;

	if (poll)
		vcs_poll_data_free(poll);
	return 0;
}

static const struct file_operations vcs_fops = {
	.llseek		= vcs_lseek,
	.read		= vcs_read,
	.write		= vcs_write,
	.poll		= vcs_poll,
	.fasync		= vcs_fasync,
	.open		= vcs_open,
	.release	= vcs_release,
};

static struct class *vc_class;

void vcs_make_sysfs(int index)
{
	device_create(vc_class, NULL, MKDEV(VCS_MAJOR, index + 1), NULL,
		      "vcs%u", index + 1);
	device_create(vc_class, NULL, MKDEV(VCS_MAJOR, index + 129), NULL,
		      "vcsa%u", index + 1);
}

void vcs_remove_sysfs(int index)
{
	device_destroy(vc_class, MKDEV(VCS_MAJOR, index + 1));
	device_destroy(vc_class, MKDEV(VCS_MAJOR, index + 129));
}

int __init vcs_init(void)
{
	unsigned int i;

	if (register_chrdev(VCS_MAJOR, "vcs", &vcs_fops))
		panic("unable to get major %d for vcs device", VCS_MAJOR);
	vc_class = class_create(THIS_MODULE, "vc");

	device_create(vc_class, NULL, MKDEV(VCS_MAJOR, 0), NULL, "vcs");
	device_create(vc_class, NULL, MKDEV(VCS_MAJOR, 128), NULL, "vcsa");
	for (i = 0; i < MIN_NR_CONSOLES; i++)
		vcs_make_sysfs(i);
	return 0;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/drivers/char/vc_screen.c
	3	*
	4	* Provide access to virtual console memory.
	5	* /dev/vcs0: the screen as it is being viewed right now (possibly scrolled)
	6	* /dev/vcsN: the screen of /dev/ttyN (1 <= N <= 63)
	7	* [minor: N]
	8	*
	9	* /dev/vcsaN: idem, but including attributes, and prefixed with
	10	* the 4 bytes lines,columns,x,y (as screendump used to give).
	11	* Attribute/character pair is in native endianity.
	12	* [minor: N+128]
	13	*
	14	* This replaces screendump and part of selection, so that the system
	15	* administrator can control access using file system permissions.
	16	*
	17	* aeb@cwi.nl - efter Friedas begravelse - 950211
	18	*
	19	* machek@k332.feld.cvut.cz - modified not to send characters to wrong console
	20	* - fixed some fatal off-by-one bugs (0-- no longer == -1 -> looping and looping and looping...)
	21	* - making it shorter - scr_readw are macros which expand in PRETTY long code
	22	*/
	23
1da177e4 LT	24	#include <linux/kernel.h>
	25	#include <linux/major.h>
	26	#include <linux/errno.h>
	27	#include <linux/tty.h>
1da177e4 LT	28	#include <linux/interrupt.h>
	29	#include <linux/mm.h>
	30	#include <linux/init.h>
c831c338	31	#include <linux/mutex.h>
1da177e4 LT	32	#include <linux/vt_kern.h>
	33	#include <linux/selection.h>
	34	#include <linux/kbd_kern.h>
	35	#include <linux/console.h>
1da177e4	36	#include <linux/device.h>
f97259e3	37	#include <linux/smp_lock.h>
47725ac7 NP	38	#include <linux/sched.h>
	39	#include <linux/fs.h>
	40	#include <linux/poll.h>
	41	#include <linux/signal.h>
	42	#include <linux/slab.h>
	43	#include <linux/notifier.h>
c831c338	44
1da177e4 LT	45	#include <asm/uaccess.h>
	46	#include <asm/byteorder.h>
	47	#include <asm/unaligned.h>
	48
	49	#undef attr
	50	#undef org
	51	#undef addr
	52	#define HEADER_SIZE 4
	53
47725ac7 NP	54	struct vcs_poll_data {
	55	struct notifier_block notifier;
	56	unsigned int cons_num;
	57	bool seen_last_update;
	58	wait_queue_head_t waitq;
	59	struct fasync_struct *fasync;
	60	};
	61
	62	static int
	63	vcs_notifier(struct notifier_block nb, unsigned long code, void _param)
	64	{
	65	struct vt_notifier_param *param = _param;
	66	struct vc_data *vc = param->vc;
	67	struct vcs_poll_data *poll =
	68	container_of(nb, struct vcs_poll_data, notifier);
	69	int currcons = poll->cons_num;
	70
	71	if (code != VT_UPDATE)
	72	return NOTIFY_DONE;
	73
	74	if (currcons == 0)
	75	currcons = fg_console;
	76	else
	77	currcons--;
	78	if (currcons != vc->vc_num)
	79	return NOTIFY_DONE;
	80
	81	poll->seen_last_update = false;
	82	wake_up_interruptible(&poll->waitq);
	83	kill_fasync(&poll->fasync, SIGIO, POLL_IN);
	84	return NOTIFY_OK;
	85	}
	86
	87	static void
	88	vcs_poll_data_free(struct vcs_poll_data *poll)
	89	{
	90	unregister_vt_notifier(&poll->notifier);
	91	kfree(poll);
	92	}
	93
	94	static struct vcs_poll_data *
	95	vcs_poll_data_get(struct file *file)
	96	{
	97	struct vcs_poll_data *poll = file->private_data;
	98
	99	if (poll)
	100	return poll;
	101
	102	poll = kzalloc(sizeof(*poll), GFP_KERNEL);
	103	if (!poll)
	104	return NULL;
	105	poll->cons_num = iminor(file->f_path.dentry->d_inode) & 127;
	106	init_waitqueue_head(&poll->waitq);
	107	poll->notifier.notifier_call = vcs_notifier;
	108	if (register_vt_notifier(&poll->notifier) != 0) {
	109	kfree(poll);
	110	return NULL;
	111	}
	112
	113	/*
	114	* This code may be called either through ->poll() or ->fasync().
	115	* If we have two threads using the same file descriptor, they could
	116	* both enter this function, both notice that the structure hasn't
	117	* been allocated yet and go ahead allocating it in parallel, but
118	* only one of them must survive and be shared otherwise we'd leak
119	* memory with a dangling notifier callback.
120	*/
121	spin_lock(&file->f_lock);
122	if (!file->private_data) {
123	file->private_data = poll;
124	} else {
125	/* someone else raced ahead of us */
126	vcs_poll_data_free(poll);
127	poll = file->private_data;
128	}
129	spin_unlock(&file->f_lock);
130
131	return poll;
132	}
133
1da177e4 LT	134	static int
	135	vcs_size(struct inode *inode)
	136	{
	137	int size;
	138	int minor = iminor(inode);
	139	int currcons = minor & 127;
	140	struct vc_data *vc;
	141
	142	if (currcons == 0)
	143	currcons = fg_console;
	144	else
	145	currcons--;
	146	if (!vc_cons_allocated(currcons))
	147	return -ENXIO;
	148	vc = vc_cons[currcons].d;
	149
	150	size = vc->vc_rows * vc->vc_cols;
	151
	152	if (minor & 128)
	153	size = 2*size + HEADER_SIZE;
	154	return size;
	155	}
	156
	157	static loff_t vcs_lseek(struct file *file, loff_t offset, int orig)
	158	{
	159	int size;
	160
c831c338	161	mutex_lock(&con_buf_mtx);
a7113a96	162	size = vcs_size(file->f_path.dentry->d_inode);
1da177e4 LT	163	switch (orig) {
1da177e4 LT	164	default:
c831c338	165	mutex_unlock(&con_buf_mtx);
1da177e4 LT	166	return -EINVAL;
	167	case 2:
	168	offset += size;
	169	break;
	170	case 1:
	171	offset += file->f_pos;
	172	case 0:
	173	break;
	174	}
	175	if (offset < 0 \|\| offset > size) {
c831c338	176	mutex_unlock(&con_buf_mtx);
1da177e4 LT	177	return -EINVAL;
	178	}
	179	file->f_pos = offset;
c831c338	180	mutex_unlock(&con_buf_mtx);
1da177e4 LT	181	return file->f_pos;
	182	}
	183
	184
	185	static ssize_t
	186	vcs_read(struct file file, char __user buf, size_t count, loff_t *ppos)
	187	{
a7113a96	188	struct inode *inode = file->f_path.dentry->d_inode;
1da177e4 LT	189	unsigned int currcons = iminor(inode);
1da177e4 LT	190	struct vc_data *vc;
47725ac7	191	struct vcs_poll_data *poll;
1da177e4 LT	192	long pos;
	193	long viewed, attr, read;
	194	int col, maxcol;
	195	unsigned short *org = NULL;
	196	ssize_t ret;
	197
c831c338	198	mutex_lock(&con_buf_mtx);
1da177e4 LT	199
	200	pos = *ppos;
	201
	202	/* Select the proper current console and verify
	203	* sanity of the situation under the console lock.
	204	*/
	205	acquire_console_sem();
	206
	207	attr = (currcons & 128);
	208	currcons = (currcons & 127);
	209	if (currcons == 0) {
	210	currcons = fg_console;
	211	viewed = 1;
	212	} else {
	213	currcons--;
	214	viewed = 0;
	215	}
	216	ret = -ENXIO;
	217	if (!vc_cons_allocated(currcons))
	218	goto unlock_out;
	219	vc = vc_cons[currcons].d;
	220
	221	ret = -EINVAL;
	222	if (pos < 0)
	223	goto unlock_out;
47725ac7 NP	224	poll = file->private_data;
	225	if (count && poll)
	226	poll->seen_last_update = true;
1da177e4 LT	227	read = 0;
	228	ret = 0;
	229	while (count) {
	230	char con_buf0, con_buf_start;
	231	long this_round, size;
	232	ssize_t orig_count;
	233	long p = pos;
	234
	235	/* Check whether we are above size each round,
	236	* as copy_to_user at the end of this loop
	237	* could sleep.
	238	*/
	239	size = vcs_size(inode);
	240	if (pos >= size)
	241	break;
	242	if (count > size - pos)
	243	count = size - pos;
	244
	245	this_round = count;
	246	if (this_round > CON_BUF_SIZE)
	247	this_round = CON_BUF_SIZE;
	248
	249	/* Perform the whole read into the local con_buf.
	250	* Then we can drop the console spinlock and safely
	251	* attempt to move it to userspace.
	252	*/
	253
	254	con_buf_start = con_buf0 = con_buf;
	255	orig_count = this_round;
	256	maxcol = vc->vc_cols;
	257	if (!attr) {
	258	org = screen_pos(vc, p, viewed);
	259	col = p % maxcol;
	260	p += maxcol - col;
	261	while (this_round-- > 0) {
	262	*con_buf0++ = (vcs_scr_readw(vc, org++) & 0xff);
	263	if (++col == maxcol) {
	264	org = screen_pos(vc, p, viewed);
	265	col = 0;
	266	p += maxcol;
	267	}
	268	}
	269	} else {
	270	if (p < HEADER_SIZE) {
	271	size_t tmp_count;
	272
	273	con_buf0[0] = (char)vc->vc_rows;
	274	con_buf0[1] = (char)vc->vc_cols;
	275	getconsxy(vc, con_buf0 + 2);
	276
	277	con_buf_start += p;
	278	this_round += p;
	279	if (this_round > CON_BUF_SIZE) {
	280	this_round = CON_BUF_SIZE;
	281	orig_count = this_round - p;
	282	}
	283
	284	tmp_count = HEADER_SIZE;
	285	if (tmp_count > this_round)
	286	tmp_count = this_round;
	287
	288	/* Advance state pointers and move on. */
	289	this_round -= tmp_count;
	290	p = HEADER_SIZE;
291	con_buf0 = con_buf + HEADER_SIZE;
292	/* If this_round >= 0, then p is even... */
293	} else if (p & 1) {
294	/* Skip first byte for output if start address is odd
295	* Update region sizes up/down depending on free
296	* space in buffer.
297	*/
298	con_buf_start++;
299	if (this_round < CON_BUF_SIZE)
300	this_round++;
301	else
302	orig_count--;
303	}
304	if (this_round > 0) {
305	unsigned short tmp_buf = (unsigned short )con_buf0;
306
307	p -= HEADER_SIZE;
308	p /= 2;
309	col = p % maxcol;
310
311	org = screen_pos(vc, p, viewed);
312	p += maxcol - col;
313
314	/* Buffer has even length, so we can always copy
315	* character + attribute. We do not copy last byte
316	* to userspace if this_round is odd.
317	*/
318	this_round = (this_round + 1) >> 1;
319
320	while (this_round) {
321	*tmp_buf++ = vcs_scr_readw(vc, org++);
322	this_round --;
323	if (++col == maxcol) {
324	org = screen_pos(vc, p, viewed);
325	col = 0;
326	p += maxcol;
327	}
328	}
329	}
330	}
331
332	/* Finally, release the console semaphore while we push
333	* all the data to userspace from our temporary buffer.
334	*
335	* AKPM: Even though it's a semaphore, we should drop it because
336	* the pagefault handling code may want to call printk().
337	*/
338
339	release_console_sem();
340	ret = copy_to_user(buf, con_buf_start, orig_count);
341	acquire_console_sem();
342
343	if (ret) {
344	read += (orig_count - ret);
345	ret = -EFAULT;
346	break;
347	}
348	buf += orig_count;
349	pos += orig_count;
350	read += orig_count;
351	count -= orig_count;
352	}
353	*ppos += read;
354	if (read)
355	ret = read;
356	unlock_out:
357	release_console_sem();
c831c338	358	mutex_unlock(&con_buf_mtx);
1da177e4 LT	359	return ret;
	360	}
	361
	362	static ssize_t
	363	vcs_write(struct file file, const char __user buf, size_t count, loff_t *ppos)
	364	{
a7113a96	365	struct inode *inode = file->f_path.dentry->d_inode;
1da177e4 LT	366	unsigned int currcons = iminor(inode);
	367	struct vc_data *vc;
	368	long pos;
	369	long viewed, attr, size, written;
	370	char *con_buf0;
	371	int col, maxcol;
	372	u16 org0 = NULL, org = NULL;
	373	size_t ret;
	374
c831c338	375	mutex_lock(&con_buf_mtx);
1da177e4 LT	376
	377	pos = *ppos;
	378
	379	/* Select the proper current console and verify
	380	* sanity of the situation under the console lock.
	381	*/
	382	acquire_console_sem();
	383
	384	attr = (currcons & 128);
	385	currcons = (currcons & 127);
	386
	387	if (currcons == 0) {
	388	currcons = fg_console;
	389	viewed = 1;
	390	} else {
	391	currcons--;
	392	viewed = 0;
	393	}
	394	ret = -ENXIO;
	395	if (!vc_cons_allocated(currcons))
	396	goto unlock_out;
	397	vc = vc_cons[currcons].d;
	398
	399	size = vcs_size(inode);
	400	ret = -EINVAL;
	401	if (pos < 0 \|\| pos > size)
	402	goto unlock_out;
	403	if (count > size - pos)
	404	count = size - pos;
	405	written = 0;
	406	while (count) {
	407	long this_round = count;
	408	size_t orig_count;
	409	long p;
	410
	411	if (this_round > CON_BUF_SIZE)
	412	this_round = CON_BUF_SIZE;
	413
	414	/* Temporarily drop the console lock so that we can read
	415	* in the write data from userspace safely.
	416	*/
	417	release_console_sem();
	418	ret = copy_from_user(con_buf, buf, this_round);
	419	acquire_console_sem();
	420
	421	if (ret) {
	422	this_round -= ret;
	423	if (!this_round) {
	424	/* Abort loop if no data were copied. Otherwise
	425	* fail with -EFAULT.
	426	*/
	427	if (written)
	428	break;
	429	ret = -EFAULT;
	430	goto unlock_out;
	431	}
	432	}
	433
	434	/* The vcs_size might have changed while we slept to grab
	435	* the user buffer, so recheck.
	436	* Return data written up to now on failure.
	437	*/
	438	size = vcs_size(inode);
	439	if (pos >= size)
440	break;
441	if (this_round > size - pos)
442	this_round = size - pos;
443
444	/* OK, now actually push the write to the console
445	* under the lock using the local kernel buffer.
446	*/
447
448	con_buf0 = con_buf;
449	orig_count = this_round;
450	maxcol = vc->vc_cols;
451	p = pos;
452	if (!attr) {
453	org0 = org = screen_pos(vc, p, viewed);
454	col = p % maxcol;
455	p += maxcol - col;
456
457	while (this_round > 0) {
458	unsigned char c = *con_buf0++;
459
460	this_round--;
461	vcs_scr_writew(vc,
462	(vcs_scr_readw(vc, org) & 0xff00) \| c, org);
463	org++;
464	if (++col == maxcol) {
465	org = screen_pos(vc, p, viewed);
466	col = 0;
467	p += maxcol;
468	}
469	}
470	} else {
471	if (p < HEADER_SIZE) {
472	char header[HEADER_SIZE];
473
474	getconsxy(vc, header + 2);
475	while (p < HEADER_SIZE && this_round > 0) {
476	this_round--;
477	header[p++] = *con_buf0++;
478	}
479	if (!viewed)
480	putconsxy(vc, header + 2);
481	}
482	p -= HEADER_SIZE;
483	col = (p/2) % maxcol;
484	if (this_round > 0) {
485	org0 = org = screen_pos(vc, p/2, viewed);
486	if ((p & 1) && this_round > 0) {
487	char c;
488
489	this_round--;
490	c = *con_buf0++;
491	#ifdef __BIG_ENDIAN
492	vcs_scr_writew(vc, c \|
493	(vcs_scr_readw(vc, org) & 0xff00), org);
494	#else
495	vcs_scr_writew(vc, (c << 8) \|
496	(vcs_scr_readw(vc, org) & 0xff), org);
497	#endif
498	org++;
499	p++;
500	if (++col == maxcol) {
501	org = screen_pos(vc, p/2, viewed);
502	col = 0;
503	}
504	}
505	p /= 2;
506	p += maxcol - col;
507	}
508	while (this_round > 1) {
509	unsigned short w;
510
ee025949	511	w = get_unaligned(((unsigned short *)con_buf0));
1da177e4 LT	512	vcs_scr_writew(vc, w, org++);
	513	con_buf0 += 2;
	514	this_round -= 2;
	515	if (++col == maxcol) {
	516	org = screen_pos(vc, p, viewed);
	517	col = 0;
	518	p += maxcol;
	519	}
	520	}
	521	if (this_round > 0) {
	522	unsigned char c;
	523
	524	c = *con_buf0++;
	525	#ifdef __BIG_ENDIAN
	526	vcs_scr_writew(vc, (vcs_scr_readw(vc, org) & 0xff) \| (c << 8), org);
	527	#else
	528	vcs_scr_writew(vc, (vcs_scr_readw(vc, org) & 0xff00) \| c, org);
	529	#endif
	530	}
	531	}
	532	count -= orig_count;
	533	written += orig_count;
	534	buf += orig_count;
	535	pos += orig_count;
	536	if (org0)
	537	update_region(vc, (unsigned long)(org0), org - org0);
	538	}
	539	*ppos += written;
	540	ret = written;
432c9ed2 NP	541	if (written)
432c9ed2 NP	542	vcs_scr_updated(vc);
1da177e4 LT	543
	544	unlock_out:
	545	release_console_sem();
	546
c831c338	547	mutex_unlock(&con_buf_mtx);
1da177e4 LT	548
	549	return ret;
	550	}
	551
47725ac7 NP	552	static unsigned int
	553	vcs_poll(struct file file, poll_table wait)
	554	{
	555	struct vcs_poll_data *poll = vcs_poll_data_get(file);
	556	int ret = 0;
	557
	558	if (poll) {
	559	poll_wait(file, &poll->waitq, wait);
	560	if (!poll->seen_last_update)
	561	ret = POLLIN \| POLLRDNORM;
	562	}
	563	return ret;
	564	}
	565
	566	static int
	567	vcs_fasync(int fd, struct file *file, int on)
	568	{
	569	struct vcs_poll_data *poll = file->private_data;
	570
	571	if (!poll) {
	572	/* don't allocate anything if all we want is disable fasync */
	573	if (!on)
	574	return 0;
	575	poll = vcs_poll_data_get(file);
	576	if (!poll)
	577	return -ENOMEM;
	578	}
	579
	580	return fasync_helper(fd, file, on, &poll->fasync);
	581	}
	582
1da177e4 LT	583	static int
	584	vcs_open(struct inode inode, struct file filp)
	585	{
	586	unsigned int currcons = iminor(inode) & 127;
f97259e3 JC	587	int ret = 0;
f97259e3 JC	588
ec79d605	589	tty_lock();
1da177e4	590	if(currcons && !vc_cons_allocated(currcons-1))
f97259e3	591	ret = -ENXIO;
ec79d605	592	tty_unlock();
f97259e3	593	return ret;
1da177e4 LT	594	}
1da177e4 LT	595
47725ac7 NP	596	static int vcs_release(struct inode inode, struct file file)
	597	{
	598	struct vcs_poll_data *poll = file->private_data;
	599
	600	if (poll)
	601	vcs_poll_data_free(poll);
	602	return 0;
	603	}
	604
62322d25	605	static const struct file_operations vcs_fops = {
1da177e4 LT	606	.llseek = vcs_lseek,
	607	.read = vcs_read,
	608	.write = vcs_write,
47725ac7 NP	609	.poll = vcs_poll,
47725ac7 NP	610	.fasync = vcs_fasync,
1da177e4	611	.open = vcs_open,
47725ac7	612	.release = vcs_release,
1da177e4 LT	613	};
1da177e4 LT	614
ca8eca68	615	static struct class *vc_class;
1da177e4	616
4995f8ef	617	void vcs_make_sysfs(int index)
1da177e4	618	{
4995f8ef KS	619	device_create(vc_class, NULL, MKDEV(VCS_MAJOR, index + 1), NULL,
	620	"vcs%u", index + 1);
	621	device_create(vc_class, NULL, MKDEV(VCS_MAJOR, index + 129), NULL,
	622	"vcsa%u", index + 1);
1da177e4	623	}
d09d7ddf	624
4995f8ef	625	void vcs_remove_sysfs(int index)
1da177e4	626	{
4995f8ef KS	627	device_destroy(vc_class, MKDEV(VCS_MAJOR, index + 1));
4995f8ef KS	628	device_destroy(vc_class, MKDEV(VCS_MAJOR, index + 129));
1da177e4 LT	629	}
	630
	631	int __init vcs_init(void)
	632	{
c46a7aec KS	633	unsigned int i;
c46a7aec KS	634
1da177e4 LT	635	if (register_chrdev(VCS_MAJOR, "vcs", &vcs_fops))
1da177e4 LT	636	panic("unable to get major %d for vcs device", VCS_MAJOR);
ca8eca68	637	vc_class = class_create(THIS_MODULE, "vc");
1da177e4	638
03457cd4 GKH	639	device_create(vc_class, NULL, MKDEV(VCS_MAJOR, 0), NULL, "vcs");
03457cd4 GKH	640	device_create(vc_class, NULL, MKDEV(VCS_MAJOR, 128), NULL, "vcsa");
c46a7aec KS	641	for (i = 0; i < MIN_NR_CONSOLES; i++)
c46a7aec KS	642	vcs_make_sysfs(i);
1da177e4 LT	643	return 0;
1da177e4 LT	644	}