[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.
 *
 * [email protected] - efter Friedas begravelse - 950211
 *
 * [email protected] - 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 <asm/uaccess.h>
#include <asm/byteorder.h>
#include <asm/unaligned.h>

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

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;
	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;
	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;

unlock_out:
	release_console_sem();

	mutex_unlock(&con_buf_mtx);

	return ret;
}

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

static const struct file_operations vcs_fops = {
	.llseek		= vcs_lseek,
	.read		= vcs_read,
	.write		= vcs_write,
	.open		= vcs_open,
};

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	* [email protected] - efter Friedas begravelse - 950211
	18	*
	19	* [email protected] - 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>
c831c338	38
1da177e4 LT	39	#include <asm/uaccess.h>
	40	#include <asm/byteorder.h>
	41	#include <asm/unaligned.h>
	42
	43	#undef attr
	44	#undef org
	45	#undef addr
	46	#define HEADER_SIZE 4
	47
	48	static int
	49	vcs_size(struct inode *inode)
	50	{
	51	int size;
	52	int minor = iminor(inode);
	53	int currcons = minor & 127;
	54	struct vc_data *vc;
	55
	56	if (currcons == 0)
	57	currcons = fg_console;
	58	else
	59	currcons--;
	60	if (!vc_cons_allocated(currcons))
	61	return -ENXIO;
	62	vc = vc_cons[currcons].d;
	63
	64	size = vc->vc_rows * vc->vc_cols;
	65
	66	if (minor & 128)
	67	size = 2*size + HEADER_SIZE;
	68	return size;
	69	}
	70
	71	static loff_t vcs_lseek(struct file *file, loff_t offset, int orig)
	72	{
	73	int size;
	74
c831c338	75	mutex_lock(&con_buf_mtx);
a7113a96	76	size = vcs_size(file->f_path.dentry->d_inode);
1da177e4 LT	77	switch (orig) {
1da177e4 LT	78	default:
c831c338	79	mutex_unlock(&con_buf_mtx);
1da177e4 LT	80	return -EINVAL;
	81	case 2:
	82	offset += size;
	83	break;
	84	case 1:
	85	offset += file->f_pos;
	86	case 0:
	87	break;
	88	}
	89	if (offset < 0 \|\| offset > size) {
c831c338	90	mutex_unlock(&con_buf_mtx);
1da177e4 LT	91	return -EINVAL;
	92	}
	93	file->f_pos = offset;
c831c338	94	mutex_unlock(&con_buf_mtx);
1da177e4 LT	95	return file->f_pos;
	96	}
	97
	98
	99	static ssize_t
	100	vcs_read(struct file file, char __user buf, size_t count, loff_t *ppos)
	101	{
a7113a96	102	struct inode *inode = file->f_path.dentry->d_inode;
1da177e4 LT	103	unsigned int currcons = iminor(inode);
	104	struct vc_data *vc;
	105	long pos;
	106	long viewed, attr, read;
	107	int col, maxcol;
	108	unsigned short *org = NULL;
	109	ssize_t ret;
	110
c831c338	111	mutex_lock(&con_buf_mtx);
1da177e4 LT	112
	113	pos = *ppos;
	114
	115	/* Select the proper current console and verify
	116	* sanity of the situation under the console lock.
	117	*/
	118	acquire_console_sem();
	119
	120	attr = (currcons & 128);
	121	currcons = (currcons & 127);
	122	if (currcons == 0) {
	123	currcons = fg_console;
	124	viewed = 1;
	125	} else {
	126	currcons--;
	127	viewed = 0;
	128	}
	129	ret = -ENXIO;
	130	if (!vc_cons_allocated(currcons))
	131	goto unlock_out;
	132	vc = vc_cons[currcons].d;
	133
	134	ret = -EINVAL;
	135	if (pos < 0)
	136	goto unlock_out;
	137	read = 0;
	138	ret = 0;
	139	while (count) {
	140	char con_buf0, con_buf_start;
	141	long this_round, size;
	142	ssize_t orig_count;
	143	long p = pos;
	144
	145	/* Check whether we are above size each round,
	146	* as copy_to_user at the end of this loop
	147	* could sleep.
	148	*/
	149	size = vcs_size(inode);
	150	if (pos >= size)
	151	break;
	152	if (count > size - pos)
	153	count = size - pos;
	154
	155	this_round = count;
	156	if (this_round > CON_BUF_SIZE)
	157	this_round = CON_BUF_SIZE;
	158
	159	/* Perform the whole read into the local con_buf.
	160	* Then we can drop the console spinlock and safely
	161	* attempt to move it to userspace.
	162	*/
	163
	164	con_buf_start = con_buf0 = con_buf;
	165	orig_count = this_round;
	166	maxcol = vc->vc_cols;
	167	if (!attr) {
	168	org = screen_pos(vc, p, viewed);
	169	col = p % maxcol;
	170	p += maxcol - col;
	171	while (this_round-- > 0) {
	172	*con_buf0++ = (vcs_scr_readw(vc, org++) & 0xff);
	173	if (++col == maxcol) {
	174	org = screen_pos(vc, p, viewed);
	175	col = 0;
176	p += maxcol;
177	}
178	}
179	} else {
180	if (p < HEADER_SIZE) {
181	size_t tmp_count;
182
183	con_buf0[0] = (char)vc->vc_rows;
184	con_buf0[1] = (char)vc->vc_cols;
185	getconsxy(vc, con_buf0 + 2);
186
187	con_buf_start += p;
188	this_round += p;
189	if (this_round > CON_BUF_SIZE) {
190	this_round = CON_BUF_SIZE;
191	orig_count = this_round - p;
192	}
193
194	tmp_count = HEADER_SIZE;
195	if (tmp_count > this_round)
196	tmp_count = this_round;
197
198	/* Advance state pointers and move on. */
199	this_round -= tmp_count;
200	p = HEADER_SIZE;
201	con_buf0 = con_buf + HEADER_SIZE;
202	/* If this_round >= 0, then p is even... */
203	} else if (p & 1) {
204	/* Skip first byte for output if start address is odd
205	* Update region sizes up/down depending on free
206	* space in buffer.
207	*/
208	con_buf_start++;
209	if (this_round < CON_BUF_SIZE)
210	this_round++;
211	else
212	orig_count--;
213	}
214	if (this_round > 0) {
215	unsigned short tmp_buf = (unsigned short )con_buf0;
216
217	p -= HEADER_SIZE;
218	p /= 2;
219	col = p % maxcol;
220
221	org = screen_pos(vc, p, viewed);
222	p += maxcol - col;
223
224	/* Buffer has even length, so we can always copy
225	* character + attribute. We do not copy last byte
226	* to userspace if this_round is odd.
227	*/
228	this_round = (this_round + 1) >> 1;
229
230	while (this_round) {
231	*tmp_buf++ = vcs_scr_readw(vc, org++);
232	this_round --;
233	if (++col == maxcol) {
234	org = screen_pos(vc, p, viewed);
235	col = 0;
236	p += maxcol;
237	}
238	}
239	}
240	}
241
242	/* Finally, release the console semaphore while we push
243	* all the data to userspace from our temporary buffer.
244	*
245	* AKPM: Even though it's a semaphore, we should drop it because
246	* the pagefault handling code may want to call printk().
247	*/
248
249	release_console_sem();
250	ret = copy_to_user(buf, con_buf_start, orig_count);
251	acquire_console_sem();
252
253	if (ret) {
254	read += (orig_count - ret);
255	ret = -EFAULT;
256	break;
257	}
258	buf += orig_count;
259	pos += orig_count;
260	read += orig_count;
261	count -= orig_count;
262	}
263	*ppos += read;
264	if (read)
265	ret = read;
266	unlock_out:
267	release_console_sem();
c831c338	268	mutex_unlock(&con_buf_mtx);
1da177e4 LT	269	return ret;
	270	}
	271
	272	static ssize_t
	273	vcs_write(struct file file, const char __user buf, size_t count, loff_t *ppos)
	274	{
a7113a96	275	struct inode *inode = file->f_path.dentry->d_inode;
1da177e4 LT	276	unsigned int currcons = iminor(inode);
	277	struct vc_data *vc;
	278	long pos;
	279	long viewed, attr, size, written;
	280	char *con_buf0;
	281	int col, maxcol;
	282	u16 org0 = NULL, org = NULL;
	283	size_t ret;
	284
c831c338	285	mutex_lock(&con_buf_mtx);
1da177e4 LT	286
	287	pos = *ppos;
	288
	289	/* Select the proper current console and verify
	290	* sanity of the situation under the console lock.
	291	*/
	292	acquire_console_sem();
	293
	294	attr = (currcons & 128);
	295	currcons = (currcons & 127);
	296
	297	if (currcons == 0) {
	298	currcons = fg_console;
	299	viewed = 1;
	300	} else {
	301	currcons--;
	302	viewed = 0;
	303	}
	304	ret = -ENXIO;
	305	if (!vc_cons_allocated(currcons))
	306	goto unlock_out;
	307	vc = vc_cons[currcons].d;
	308
	309	size = vcs_size(inode);
	310	ret = -EINVAL;
	311	if (pos < 0 \|\| pos > size)
	312	goto unlock_out;
	313	if (count > size - pos)
	314	count = size - pos;
	315	written = 0;
	316	while (count) {
	317	long this_round = count;
	318	size_t orig_count;
	319	long p;
	320
	321	if (this_round > CON_BUF_SIZE)
	322	this_round = CON_BUF_SIZE;
	323
	324	/* Temporarily drop the console lock so that we can read
	325	* in the write data from userspace safely.
	326	*/
	327	release_console_sem();
	328	ret = copy_from_user(con_buf, buf, this_round);
	329	acquire_console_sem();
	330
	331	if (ret) {
	332	this_round -= ret;
	333	if (!this_round) {
	334	/* Abort loop if no data were copied. Otherwise
	335	* fail with -EFAULT.
	336	*/
	337	if (written)
	338	break;
	339	ret = -EFAULT;
	340	goto unlock_out;
	341	}
	342	}
	343
	344	/* The vcs_size might have changed while we slept to grab
	345	* the user buffer, so recheck.
	346	* Return data written up to now on failure.
	347	*/
	348	size = vcs_size(inode);
	349	if (pos >= size)
350	break;
351	if (this_round > size - pos)
352	this_round = size - pos;
353
354	/* OK, now actually push the write to the console
355	* under the lock using the local kernel buffer.
356	*/
357
358	con_buf0 = con_buf;
359	orig_count = this_round;
360	maxcol = vc->vc_cols;
361	p = pos;
362	if (!attr) {
363	org0 = org = screen_pos(vc, p, viewed);
364	col = p % maxcol;
365	p += maxcol - col;
366
367	while (this_round > 0) {
368	unsigned char c = *con_buf0++;
369
370	this_round--;
371	vcs_scr_writew(vc,
372	(vcs_scr_readw(vc, org) & 0xff00) \| c, org);
373	org++;
374	if (++col == maxcol) {
375	org = screen_pos(vc, p, viewed);
376	col = 0;
377	p += maxcol;
378	}
379	}
380	} else {
381	if (p < HEADER_SIZE) {
382	char header[HEADER_SIZE];
383
384	getconsxy(vc, header + 2);
385	while (p < HEADER_SIZE && this_round > 0) {
386	this_round--;
387	header[p++] = *con_buf0++;
388	}
389	if (!viewed)
390	putconsxy(vc, header + 2);
391	}
392	p -= HEADER_SIZE;
393	col = (p/2) % maxcol;
394	if (this_round > 0) {
395	org0 = org = screen_pos(vc, p/2, viewed);
396	if ((p & 1) && this_round > 0) {
397	char c;
398
399	this_round--;
400	c = *con_buf0++;
401	#ifdef __BIG_ENDIAN
402	vcs_scr_writew(vc, c \|
403	(vcs_scr_readw(vc, org) & 0xff00), org);
404	#else
405	vcs_scr_writew(vc, (c << 8) \|
406	(vcs_scr_readw(vc, org) & 0xff), org);
407	#endif
408	org++;
409	p++;
410	if (++col == maxcol) {
411	org = screen_pos(vc, p/2, viewed);
412	col = 0;
413	}
414	}
415	p /= 2;
416	p += maxcol - col;
417	}
418	while (this_round > 1) {
419	unsigned short w;
420
ee025949	421	w = get_unaligned(((unsigned short *)con_buf0));
1da177e4 LT	422	vcs_scr_writew(vc, w, org++);
	423	con_buf0 += 2;
	424	this_round -= 2;
	425	if (++col == maxcol) {
	426	org = screen_pos(vc, p, viewed);
	427	col = 0;
	428	p += maxcol;
	429	}
	430	}
	431	if (this_round > 0) {
	432	unsigned char c;
	433
	434	c = *con_buf0++;
	435	#ifdef __BIG_ENDIAN
	436	vcs_scr_writew(vc, (vcs_scr_readw(vc, org) & 0xff) \| (c << 8), org);
	437	#else
	438	vcs_scr_writew(vc, (vcs_scr_readw(vc, org) & 0xff00) \| c, org);
	439	#endif
	440	}
	441	}
	442	count -= orig_count;
	443	written += orig_count;
	444	buf += orig_count;
	445	pos += orig_count;
	446	if (org0)
	447	update_region(vc, (unsigned long)(org0), org - org0);
	448	}
	449	*ppos += written;
	450	ret = written;
	451
	452	unlock_out:
	453	release_console_sem();
	454
c831c338	455	mutex_unlock(&con_buf_mtx);
1da177e4 LT	456
	457	return ret;
	458	}
	459
	460	static int
	461	vcs_open(struct inode inode, struct file filp)
	462	{
	463	unsigned int currcons = iminor(inode) & 127;
f97259e3 JC	464	int ret = 0;
	465
	466	lock_kernel();
1da177e4	467	if(currcons && !vc_cons_allocated(currcons-1))
f97259e3 JC	468	ret = -ENXIO;
	469	unlock_kernel();
	470	return ret;
1da177e4 LT	471	}
1da177e4 LT	472
62322d25	473	static const struct file_operations vcs_fops = {
1da177e4 LT	474	.llseek = vcs_lseek,
	475	.read = vcs_read,
	476	.write = vcs_write,
	477	.open = vcs_open,
	478	};
	479
ca8eca68	480	static struct class *vc_class;
1da177e4	481
4995f8ef	482	void vcs_make_sysfs(int index)
1da177e4	483	{
4995f8ef KS	484	device_create(vc_class, NULL, MKDEV(VCS_MAJOR, index + 1), NULL,
	485	"vcs%u", index + 1);
	486	device_create(vc_class, NULL, MKDEV(VCS_MAJOR, index + 129), NULL,
	487	"vcsa%u", index + 1);
1da177e4	488	}
d09d7ddf	489
4995f8ef	490	void vcs_remove_sysfs(int index)
1da177e4	491	{
4995f8ef KS	492	device_destroy(vc_class, MKDEV(VCS_MAJOR, index + 1));
4995f8ef KS	493	device_destroy(vc_class, MKDEV(VCS_MAJOR, index + 129));
1da177e4 LT	494	}
	495
	496	int __init vcs_init(void)
	497	{
c46a7aec KS	498	unsigned int i;
c46a7aec KS	499
1da177e4 LT	500	if (register_chrdev(VCS_MAJOR, "vcs", &vcs_fops))
1da177e4 LT	501	panic("unable to get major %d for vcs device", VCS_MAJOR);
ca8eca68	502	vc_class = class_create(THIS_MODULE, "vc");
1da177e4	503
03457cd4 GKH	504	device_create(vc_class, NULL, MKDEV(VCS_MAJOR, 0), NULL, "vcs");
03457cd4 GKH	505	device_create(vc_class, NULL, MKDEV(VCS_MAJOR, 128), NULL, "vcsa");
c46a7aec KS	506	for (i = 0; i < MIN_NR_CONSOLES; i++)
c46a7aec KS	507	vcs_make_sysfs(i);
1da177e4 LT	508	return 0;
1da177e4 LT	509	}