1 // SPDX-License-Identifier: GPL-2.0
3  * Provide access to virtual console memory.
13  * /dev/vcsuN: similar to /dev/vcsaN but using 4-byte unicode values
14  *	instead of 1-byte screen glyph values.
22  * [email protected] - efter Friedas begravelse - 950211
24  * [email protected] - modified not to send characters to wrong console
25  *	 - fixed some fatal off-by-one bugs (0-- no longer == -1 -> looping and looping and looping...)
26  *	 - making it shorter - scr_readw are macros which expand in PRETTY long code
40 #include <linux/console.h>
65  * with minors 0, 64, 128 and 192 being proxies for the foreground console.
71 #define console(inode)		(iminor(inode) & 63)  macro
88 	struct vc_data *vc = param->vc;  in vcs_notifier()
91 	int currcons = poll->cons_num;  in vcs_notifier()
108 		currcons--;  in vcs_notifier()
109 	if (currcons != vc->vc_num)  in vcs_notifier()
112 	poll->event = code;  in vcs_notifier()
113 	wake_up_interruptible(&poll->waitq);  in vcs_notifier()
114 	kill_fasync(&poll->fasync, SIGIO, fa_band);  in vcs_notifier()
121 	unregister_vt_notifier(&poll->notifier);  in vcs_poll_data_free()
128 	struct vcs_poll_data *poll = file->private_data, *kill = NULL;  in vcs_poll_data_get()
136 	poll->cons_num = console(file_inode(file));  in vcs_poll_data_get()
137 	init_waitqueue_head(&poll->waitq);  in vcs_poll_data_get()
138 	poll->notifier.notifier_call = vcs_notifier;  in vcs_poll_data_get()
146 	poll->event = VT_UPDATE;  in vcs_poll_data_get()
148 	if (register_vt_notifier(&poll->notifier) != 0) {  in vcs_poll_data_get()
154 	 * This code may be called either through ->poll() or ->fasync().  in vcs_poll_data_get()
161 	spin_lock(&file->f_lock);  in vcs_poll_data_get()
162 	if (!file->private_data) {  in vcs_poll_data_get()
163 		file->private_data = poll;  in vcs_poll_data_get()
167 		poll = file->private_data;  in vcs_poll_data_get()
169 	spin_unlock(&file->f_lock);  in vcs_poll_data_get()
177  * vcs_vc - return VC for @inode
179  * @viewed: returns whether this console is currently foreground (viewed)
185 	unsigned int currcons = console(inode);  in vcs_vc()
194 		currcons--;  in vcs_vc()
202  * vcs_size - return size for a VC in @vc
211 	int size;  in vcs_size()  local
215 	size = vc->vc_rows * vc->vc_cols;  in vcs_size()
219 			return -EOPNOTSUPP;  in vcs_size()
221 		size = 2 * size + HEADER_SIZE;  in vcs_size()
223 		size *= 4;  in vcs_size()
225 	return size;  in vcs_size()
232 	int size;  in vcs_lseek()  local
238 		return -ENXIO;  in vcs_lseek()
241 	size = vcs_size(vc, use_attributes(inode), use_unicode(inode));  in vcs_lseek()
243 	if (size < 0)  in vcs_lseek()
244 		return size;  in vcs_lseek()
245 	return fixed_size_llseek(file, offset, orig, size);  in vcs_lseek()
251 	unsigned int nr, row, col, maxcol = vc->vc_cols;  in vcs_read_buf_uni()
261 	nr = maxcol - col;  in vcs_read_buf_uni()
267 		count -= nr * 4;  in vcs_read_buf_uni()
280 	unsigned int col, maxcol = vc->vc_cols;  in vcs_read_buf_noattr()
284 	pos += maxcol - col;  in vcs_read_buf_noattr()
286 	while (count-- > 0) {  in vcs_read_buf_noattr()
301 	unsigned int col, maxcol = vc->vc_cols;  in vcs_read_buf()
306 		con_buf[0] = min(vc->vc_rows, 0xFFu);  in vcs_read_buf()
307 		con_buf[1] = min(vc->vc_cols, 0xFFu);  in vcs_read_buf()
314 			filled = count - pos;  in vcs_read_buf()
318 		count -= min(HEADER_SIZE, count);  in vcs_read_buf()
331 			filled--;  in vcs_read_buf()
337 	pos -= HEADER_SIZE;  in vcs_read_buf()
342 	pos += maxcol - col;  in vcs_read_buf()
353 		count--;  in vcs_read_buf()
378 		return -ENOMEM;  in vcs_read()
382 	/* Select the proper current console and verify  in vcs_read()
383 	 * sanity of the situation under the console lock.  in vcs_read()
390 	ret = -EINVAL;  in vcs_read()
393 	/* we enforce 32-bit alignment for pos and count in unicode mode */  in vcs_read()
397 	poll = file->private_data;  in vcs_read()
399 		poll->event = 0;  in vcs_read()
404 		int size;  in vcs_read()  local
408 			ret = -ENXIO;  in vcs_read()
412 		/* Check whether we are above size each round,  in vcs_read()
416 		size = vcs_size(vc, attr, uni_mode);  in vcs_read()
417 		if (size < 0) {  in vcs_read()
418 			ret = size;  in vcs_read()
421 		if (pos >= size)  in vcs_read()
423 		if (count > size - pos)  in vcs_read()
424 			count = size - pos;  in vcs_read()
431 		 * Then we can drop the console spinlock and safely  in vcs_read()
448 		/* Finally, release the console semaphore while we push  in vcs_read()
460 			read += this_round - ret;  in vcs_read()
461 			ret = -EFAULT;  in vcs_read()
467 		count -= this_round;  in vcs_read()
482 	unsigned int col, maxcol = vc->vc_cols;  in vcs_write_buf_noattr()
486 	pos += maxcol - col;  in vcs_write_buf_noattr()
491 		count--;  in vcs_write_buf_noattr()
522 	unsigned int col, maxcol = vc->vc_cols;  in vcs_write_buf()
531 			count--;  in vcs_write_buf()
541 	pos -= HEADER_SIZE;  in vcs_write_buf()
546 	/* odd pos -- the first single character */  in vcs_write_buf()
548 		count--;  in vcs_write_buf()
561 	pos += maxcol - col;  in vcs_write_buf()
563 	/* even pos -- handle attr+character pairs */  in vcs_write_buf()
570 		count -= 2;  in vcs_write_buf()
581 	/* odd pos -- the remaining character */  in vcs_write_buf()
597 	int size;  in vcs_write()  local
603 		return -EOPNOTSUPP;  in vcs_write()
607 		return -ENOMEM;  in vcs_write()
611 	/* Select the proper current console and verify  in vcs_write()
612 	 * sanity of the situation under the console lock.  in vcs_write()
617 	ret = -ENXIO;  in vcs_write()
622 	size = vcs_size(vc, attr, false);  in vcs_write()
623 	if (size < 0) {  in vcs_write()
624 		ret = size;  in vcs_write()
627 	ret = -EINVAL;  in vcs_write()
628 	if (pos < 0 || pos > size)  in vcs_write()
630 	if (count > size - pos)  in vcs_write()
631 		count = size - pos;  in vcs_write()
639 		/* Temporarily drop the console lock so that we can read  in vcs_write()
647 			this_round -= ret;  in vcs_write()
650 				 * fail with -EFAULT.  in vcs_write()
654 				ret = -EFAULT;  in vcs_write()
667 			ret = -ENXIO;  in vcs_write()
670 		size = vcs_size(vc, attr, false);  in vcs_write()
671 		if (size < 0) {  in vcs_write()
674 			ret = size;  in vcs_write()
677 		if (pos >= size)  in vcs_write()
679 		if (this_round > size - pos)  in vcs_write()
680 			this_round = size - pos;  in vcs_write()
682 		/* OK, now actually push the write to the console  in vcs_write()
693 		count -= this_round;  in vcs_write()
698 			update_region(vc, (unsigned long)(org0), org - org0);  in vcs_write()
718 		poll_wait(file, &poll->waitq, wait);  in vcs_poll()
719 		switch (poll->event) {  in vcs_poll()
737 	struct vcs_poll_data *poll = file->private_data;  in vcs_fasync()
745 			return -ENOMEM;  in vcs_fasync()
748 	return fasync_helper(fd, file, on, &poll->fasync);  in vcs_fasync()
754 	unsigned int currcons = console(inode);  in vcs_open()
761 		return -EOPNOTSUPP;  in vcs_open()
764 	if(currcons && !vc_cons_allocated(currcons-1))  in vcs_open()
765 		ret = -ENXIO;  in vcs_open()
772 	struct vcs_poll_data *poll = file->private_data;  in vcs_release()