1// SPDX-License-Identifier: GPL-2.0
2/*
3 * IBM/3270 Driver - fullscreen driver.
4 *
5 * Author(s):
6 *   Original 3270 Code for 2.4 written by Richard Hitt (UTS Global)
7 *   Rewritten for 2.5/2.6 by Martin Schwidefsky <schwidefsky@de.ibm.com>
8 *     Copyright IBM Corp. 2003, 2009
9 */
10
11#include <linux/memblock.h>
12#include <linux/console.h>
13#include <linux/init.h>
14#include <linux/interrupt.h>
15#include <linux/compat.h>
16#include <linux/sched/signal.h>
17#include <linux/module.h>
18#include <linux/list.h>
19#include <linux/slab.h>
20#include <linux/types.h>
21
22#include <asm/ccwdev.h>
23#include <asm/cio.h>
24#include <asm/ebcdic.h>
25#include <asm/idals.h>
26
27#include "raw3270.h"
28#include "ctrlchar.h"
29
30static struct raw3270_fn fs3270_fn;
31
32struct fs3270 {
33	struct raw3270_view view;
34	struct pid *fs_pid;		/* Pid of controlling program. */
35	int read_command;		/* ccw command to use for reads. */
36	int write_command;		/* ccw command to use for writes. */
37	int attention;			/* Got attention. */
38	int active;			/* Fullscreen view is active. */
39	struct raw3270_request *init;	/* single init request. */
40	wait_queue_head_t wait;		/* Init & attention wait queue. */
41	struct idal_buffer *rdbuf;	/* full-screen-deactivate buffer */
42	size_t rdbuf_size;		/* size of data returned by RDBUF */
43};
44
45static DEFINE_MUTEX(fs3270_mutex);
46
47static void
48fs3270_wake_up(struct raw3270_request *rq, void *data)
49{
50	wake_up((wait_queue_head_t *) data);
51}
52
53static inline int
54fs3270_working(struct fs3270 *fp)
55{
56	/*
57	 * The fullscreen view is in working order if the view
58	 * has been activated AND the initial request is finished.
59	 */
60	return fp->active && raw3270_request_final(fp->init);
61}
62
63static int
64fs3270_do_io(struct raw3270_view *view, struct raw3270_request *rq)
65{
66	struct fs3270 *fp;
67	int rc;
68
69	fp = (struct fs3270 *) view;
70	rq->callback = fs3270_wake_up;
71	rq->callback_data = &fp->wait;
72
73	do {
74		if (!fs3270_working(fp)) {
75			/* Fullscreen view isn't ready yet. */
76			rc = wait_event_interruptible(fp->wait,
77						      fs3270_working(fp));
78			if (rc != 0)
79				break;
80		}
81		rc = raw3270_start(view, rq);
82		if (rc == 0) {
83			/* Started successfully. Now wait for completion. */
84			wait_event(fp->wait, raw3270_request_final(rq));
85		}
86	} while (rc == -EACCES);
87	return rc;
88}
89
90/*
91 * Switch to the fullscreen view.
92 */
93static void
94fs3270_reset_callback(struct raw3270_request *rq, void *data)
95{
96	struct fs3270 *fp;
97
98	fp = (struct fs3270 *) rq->view;
99	raw3270_request_reset(rq);
100	wake_up(&fp->wait);
101}
102
103static void
104fs3270_restore_callback(struct raw3270_request *rq, void *data)
105{
106	struct fs3270 *fp;
107
108	fp = (struct fs3270 *) rq->view;
109	if (rq->rc != 0 || rq->rescnt != 0) {
110		if (fp->fs_pid)
111			kill_pid(fp->fs_pid, SIGHUP, 1);
112	}
113	fp->rdbuf_size = 0;
114	raw3270_request_reset(rq);
115	wake_up(&fp->wait);
116}
117
118static int
119fs3270_activate(struct raw3270_view *view)
120{
121	struct fs3270 *fp;
122	char *cp;
123	int rc;
124
125	fp = (struct fs3270 *) view;
126
127	/* If an old init command is still running just return. */
128	if (!raw3270_request_final(fp->init))
129		return 0;
130
131	if (fp->rdbuf_size == 0) {
132		/* No saved buffer. Just clear the screen. */
133		raw3270_request_set_cmd(fp->init, TC_EWRITEA);
134		fp->init->callback = fs3270_reset_callback;
135	} else {
136		/* Restore fullscreen buffer saved by fs3270_deactivate. */
137		raw3270_request_set_cmd(fp->init, TC_EWRITEA);
138		raw3270_request_set_idal(fp->init, fp->rdbuf);
139		fp->init->ccw.count = fp->rdbuf_size;
140		cp = fp->rdbuf->data[0];
141		cp[0] = TW_KR;
142		cp[1] = TO_SBA;
143		cp[2] = cp[6];
144		cp[3] = cp[7];
145		cp[4] = TO_IC;
146		cp[5] = TO_SBA;
147		cp[6] = 0x40;
148		cp[7] = 0x40;
149		fp->init->rescnt = 0;
150		fp->init->callback = fs3270_restore_callback;
151	}
152	rc = fp->init->rc = raw3270_start_locked(view, fp->init);
153	if (rc)
154		fp->init->callback(fp->init, NULL);
155	else
156		fp->active = 1;
157	return rc;
158}
159
160/*
161 * Shutdown fullscreen view.
162 */
163static void
164fs3270_save_callback(struct raw3270_request *rq, void *data)
165{
166	struct fs3270 *fp;
167
168	fp = (struct fs3270 *) rq->view;
169
170	/* Correct idal buffer element 0 address. */
171	fp->rdbuf->data[0] -= 5;
172	fp->rdbuf->size += 5;
173
174	/*
175	 * If the rdbuf command failed or the idal buffer is
176	 * to small for the amount of data returned by the
177	 * rdbuf command, then we have no choice but to send
178	 * a SIGHUP to the application.
179	 */
180	if (rq->rc != 0 || rq->rescnt == 0) {
181		if (fp->fs_pid)
182			kill_pid(fp->fs_pid, SIGHUP, 1);
183		fp->rdbuf_size = 0;
184	} else
185		fp->rdbuf_size = fp->rdbuf->size - rq->rescnt;
186	raw3270_request_reset(rq);
187	wake_up(&fp->wait);
188}
189
190static void
191fs3270_deactivate(struct raw3270_view *view)
192{
193	struct fs3270 *fp;
194
195	fp = (struct fs3270 *) view;
196	fp->active = 0;
197
198	/* If an old init command is still running just return. */
199	if (!raw3270_request_final(fp->init))
200		return;
201
202	/* Prepare read-buffer request. */
203	raw3270_request_set_cmd(fp->init, TC_RDBUF);
204	/*
205	 * Hackish: skip first 5 bytes of the idal buffer to make
206	 * room for the TW_KR/TO_SBA/<address>/<address>/TO_IC sequence
207	 * in the activation command.
208	 */
209	fp->rdbuf->data[0] += 5;
210	fp->rdbuf->size -= 5;
211	raw3270_request_set_idal(fp->init, fp->rdbuf);
212	fp->init->rescnt = 0;
213	fp->init->callback = fs3270_save_callback;
214
215	/* Start I/O to read in the 3270 buffer. */
216	fp->init->rc = raw3270_start_locked(view, fp->init);
217	if (fp->init->rc)
218		fp->init->callback(fp->init, NULL);
219}
220
221static void
222fs3270_irq(struct fs3270 *fp, struct raw3270_request *rq, struct irb *irb)
223{
224	/* Handle ATTN. Set indication and wake waiters for attention. */
225	if (irb->scsw.cmd.dstat & DEV_STAT_ATTENTION) {
226		fp->attention = 1;
227		wake_up(&fp->wait);
228	}
229
230	if (rq) {
231		if (irb->scsw.cmd.dstat & DEV_STAT_UNIT_CHECK)
232			rq->rc = -EIO;
233		else
234			/* Normal end. Copy residual count. */
235			rq->rescnt = irb->scsw.cmd.count;
236	}
237}
238
239/*
240 * Process reads from fullscreen 3270.
241 */
242static ssize_t
243fs3270_read(struct file *filp, char __user *data, size_t count, loff_t *off)
244{
245	struct fs3270 *fp;
246	struct raw3270_request *rq;
247	struct idal_buffer *ib;
248	ssize_t rc;
249
250	if (count == 0 || count > 65535)
251		return -EINVAL;
252	fp = filp->private_data;
253	if (!fp)
254		return -ENODEV;
255	ib = idal_buffer_alloc(count, 0);
256	if (IS_ERR(ib))
257		return -ENOMEM;
258	rq = raw3270_request_alloc(0);
259	if (!IS_ERR(rq)) {
260		if (fp->read_command == 0 && fp->write_command != 0)
261			fp->read_command = 6;
262		raw3270_request_set_cmd(rq, fp->read_command ? : 2);
263		raw3270_request_set_idal(rq, ib);
264		rc = wait_event_interruptible(fp->wait, fp->attention);
265		fp->attention = 0;
266		if (rc == 0) {
267			rc = fs3270_do_io(&fp->view, rq);
268			if (rc == 0) {
269				count -= rq->rescnt;
270				if (idal_buffer_to_user(ib, data, count) != 0)
271					rc = -EFAULT;
272				else
273					rc = count;
274
275			}
276		}
277		raw3270_request_free(rq);
278	} else
279		rc = PTR_ERR(rq);
280	idal_buffer_free(ib);
281	return rc;
282}
283
284/*
285 * Process writes to fullscreen 3270.
286 */
287static ssize_t
288fs3270_write(struct file *filp, const char __user *data, size_t count, loff_t *off)
289{
290	struct fs3270 *fp;
291	struct raw3270_request *rq;
292	struct idal_buffer *ib;
293	int write_command;
294	ssize_t rc;
295
296	fp = filp->private_data;
297	if (!fp)
298		return -ENODEV;
299	ib = idal_buffer_alloc(count, 0);
300	if (IS_ERR(ib))
301		return -ENOMEM;
302	rq = raw3270_request_alloc(0);
303	if (!IS_ERR(rq)) {
304		if (idal_buffer_from_user(ib, data, count) == 0) {
305			write_command = fp->write_command ? : 1;
306			if (write_command == 5)
307				write_command = 13;
308			raw3270_request_set_cmd(rq, write_command);
309			raw3270_request_set_idal(rq, ib);
310			rc = fs3270_do_io(&fp->view, rq);
311			if (rc == 0)
312				rc = count - rq->rescnt;
313		} else
314			rc = -EFAULT;
315		raw3270_request_free(rq);
316	} else
317		rc = PTR_ERR(rq);
318	idal_buffer_free(ib);
319	return rc;
320}
321
322/*
323 * process ioctl commands for the tube driver
324 */
325static long
326fs3270_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
327{
328	char __user *argp;
329	struct fs3270 *fp;
330	struct raw3270_iocb iocb;
331	int rc;
332
333	fp = filp->private_data;
334	if (!fp)
335		return -ENODEV;
336	if (is_compat_task())
337		argp = compat_ptr(arg);
338	else
339		argp = (char __user *)arg;
340	rc = 0;
341	mutex_lock(&fs3270_mutex);
342	switch (cmd) {
343	case TUBICMD:
344		fp->read_command = arg;
345		break;
346	case TUBOCMD:
347		fp->write_command = arg;
348		break;
349	case TUBGETI:
350		rc = put_user(fp->read_command, argp);
351		break;
352	case TUBGETO:
353		rc = put_user(fp->write_command, argp);
354		break;
355	case TUBGETMOD:
356		iocb.model = fp->view.model;
357		iocb.line_cnt = fp->view.rows;
358		iocb.col_cnt = fp->view.cols;
359		iocb.pf_cnt = 24;
360		iocb.re_cnt = 20;
361		iocb.map = 0;
362		if (copy_to_user(argp, &iocb, sizeof(struct raw3270_iocb)))
363			rc = -EFAULT;
364		break;
365	}
366	mutex_unlock(&fs3270_mutex);
367	return rc;
368}
369
370/*
371 * Allocate fs3270 structure.
372 */
373static struct fs3270 *
374fs3270_alloc_view(void)
375{
376	struct fs3270 *fp;
377
378	fp = kzalloc(sizeof(struct fs3270),GFP_KERNEL);
379	if (!fp)
380		return ERR_PTR(-ENOMEM);
381	fp->init = raw3270_request_alloc(0);
382	if (IS_ERR(fp->init)) {
383		kfree(fp);
384		return ERR_PTR(-ENOMEM);
385	}
386	return fp;
387}
388
389/*
390 * Free fs3270 structure.
391 */
392static void
393fs3270_free_view(struct raw3270_view *view)
394{
395	struct fs3270 *fp;
396
397	fp = (struct fs3270 *) view;
398	if (fp->rdbuf)
399		idal_buffer_free(fp->rdbuf);
400	raw3270_request_free(((struct fs3270 *) view)->init);
401	kfree(view);
402}
403
404/*
405 * Unlink fs3270 data structure from filp.
406 */
407static void
408fs3270_release(struct raw3270_view *view)
409{
410	struct fs3270 *fp;
411
412	fp = (struct fs3270 *) view;
413	if (fp->fs_pid)
414		kill_pid(fp->fs_pid, SIGHUP, 1);
415}
416
417/* View to a 3270 device. Can be console, tty or fullscreen. */
418static struct raw3270_fn fs3270_fn = {
419	.activate = fs3270_activate,
420	.deactivate = fs3270_deactivate,
421	.intv = (void *) fs3270_irq,
422	.release = fs3270_release,
423	.free = fs3270_free_view
424};
425
426/*
427 * This routine is called whenever a 3270 fullscreen device is opened.
428 */
429static int
430fs3270_open(struct inode *inode, struct file *filp)
431{
432	struct fs3270 *fp;
433	struct idal_buffer *ib;
434	int minor, rc = 0;
435
436	if (imajor(file_inode(filp)) != IBM_FS3270_MAJOR)
437		return -ENODEV;
438	minor = iminor(file_inode(filp));
439	/* Check for minor 0 multiplexer. */
440	if (minor == 0) {
441		struct tty_struct *tty = get_current_tty();
442		if (!tty || tty->driver->major != IBM_TTY3270_MAJOR) {
443			tty_kref_put(tty);
444			return -ENODEV;
445		}
446		minor = tty->index;
447		tty_kref_put(tty);
448	}
449	mutex_lock(&fs3270_mutex);
450	/* Check if some other program is already using fullscreen mode. */
451	fp = (struct fs3270 *) raw3270_find_view(&fs3270_fn, minor);
452	if (!IS_ERR(fp)) {
453		raw3270_put_view(&fp->view);
454		rc = -EBUSY;
455		goto out;
456	}
457	/* Allocate fullscreen view structure. */
458	fp = fs3270_alloc_view();
459	if (IS_ERR(fp)) {
460		rc = PTR_ERR(fp);
461		goto out;
462	}
463
464	init_waitqueue_head(&fp->wait);
465	fp->fs_pid = get_pid(task_pid(current));
466	rc = raw3270_add_view(&fp->view, &fs3270_fn, minor,
467			      RAW3270_VIEW_LOCK_BH);
468	if (rc) {
469		fs3270_free_view(&fp->view);
470		goto out;
471	}
472
473	/* Allocate idal-buffer. */
474	ib = idal_buffer_alloc(2*fp->view.rows*fp->view.cols + 5, 0);
475	if (IS_ERR(ib)) {
476		raw3270_put_view(&fp->view);
477		raw3270_del_view(&fp->view);
478		rc = PTR_ERR(ib);
479		goto out;
480	}
481	fp->rdbuf = ib;
482
483	rc = raw3270_activate_view(&fp->view);
484	if (rc) {
485		raw3270_put_view(&fp->view);
486		raw3270_del_view(&fp->view);
487		goto out;
488	}
489	stream_open(inode, filp);
490	filp->private_data = fp;
491out:
492	mutex_unlock(&fs3270_mutex);
493	return rc;
494}
495
496/*
497 * This routine is called when the 3270 tty is closed. We wait
498 * for the remaining request to be completed. Then we clean up.
499 */
500static int
501fs3270_close(struct inode *inode, struct file *filp)
502{
503	struct fs3270 *fp;
504
505	fp = filp->private_data;
506	filp->private_data = NULL;
507	if (fp) {
508		put_pid(fp->fs_pid);
509		fp->fs_pid = NULL;
510		raw3270_reset(&fp->view);
511		raw3270_put_view(&fp->view);
512		raw3270_del_view(&fp->view);
513	}
514	return 0;
515}
516
517static const struct file_operations fs3270_fops = {
518	.owner		 = THIS_MODULE,		/* owner */
519	.read		 = fs3270_read,		/* read */
520	.write		 = fs3270_write,	/* write */
521	.unlocked_ioctl	 = fs3270_ioctl,	/* ioctl */
522	.compat_ioctl	 = fs3270_ioctl,	/* ioctl */
523	.open		 = fs3270_open,		/* open */
524	.release	 = fs3270_close,	/* release */
525	.llseek		= no_llseek,
526};
527
528static void fs3270_create_cb(int minor)
529{
530	__register_chrdev(IBM_FS3270_MAJOR, minor, 1, "tub", &fs3270_fops);
531	device_create(class3270, NULL, MKDEV(IBM_FS3270_MAJOR, minor),
532		      NULL, "3270/tub%d", minor);
533}
534
535static void fs3270_destroy_cb(int minor)
536{
537	device_destroy(class3270, MKDEV(IBM_FS3270_MAJOR, minor));
538	__unregister_chrdev(IBM_FS3270_MAJOR, minor, 1, "tub");
539}
540
541static struct raw3270_notifier fs3270_notifier =
542{
543	.create = fs3270_create_cb,
544	.destroy = fs3270_destroy_cb,
545};
546
547/*
548 * 3270 fullscreen driver initialization.
549 */
550static int __init
551fs3270_init(void)
552{
553	int rc;
554
555	rc = __register_chrdev(IBM_FS3270_MAJOR, 0, 1, "fs3270", &fs3270_fops);
556	if (rc)
557		return rc;
558	device_create(class3270, NULL, MKDEV(IBM_FS3270_MAJOR, 0),
559		      NULL, "3270/tub");
560	raw3270_register_notifier(&fs3270_notifier);
561	return 0;
562}
563
564static void __exit
565fs3270_exit(void)
566{
567	raw3270_unregister_notifier(&fs3270_notifier);
568	device_destroy(class3270, MKDEV(IBM_FS3270_MAJOR, 0));
569	__unregister_chrdev(IBM_FS3270_MAJOR, 0, 1, "fs3270");
570}
571
572MODULE_LICENSE("GPL");
573MODULE_ALIAS_CHARDEV_MAJOR(IBM_FS3270_MAJOR);
574
575module_init(fs3270_init);
576module_exit(fs3270_exit);
577