1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * character device frontend for tape device driver
4 *
5 * S390 and zSeries version
6 * Copyright IBM Corp. 2001, 2006
7 * Author(s): Carsten Otte <cotte@de.ibm.com>
8 * Michael Holzheu <holzheu@de.ibm.com>
9 * Tuan Ngo-Anh <ngoanh@de.ibm.com>
10 * Martin Schwidefsky <schwidefsky@de.ibm.com>
11 */
12
13 #define KMSG_COMPONENT "tape"
14 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
15
16 #include <linux/module.h>
17 #include <linux/types.h>
18 #include <linux/proc_fs.h>
19 #include <linux/mtio.h>
20 #include <linux/compat.h>
21
22 #include <linux/uaccess.h>
23
24 #define TAPE_DBF_AREA tape_core_dbf
25
26 #include "tape.h"
27 #include "tape_std.h"
28 #include "tape_class.h"
29
30 #define TAPECHAR_MAJOR 0 /* get dynamic major */
31
32 /*
33 * file operation structure for tape character frontend
34 */
35 static ssize_t tapechar_read(struct file *, char __user *, size_t, loff_t *);
36 static ssize_t tapechar_write(struct file *, const char __user *, size_t, loff_t *);
37 static int tapechar_open(struct inode *,struct file *);
38 static int tapechar_release(struct inode *,struct file *);
39 static long tapechar_ioctl(struct file *, unsigned int, unsigned long);
40 #ifdef CONFIG_COMPAT
41 static long tapechar_compat_ioctl(struct file *, unsigned int, unsigned long);
42 #endif
43
44 static const struct file_operations tape_fops =
45 {
46 .owner = THIS_MODULE,
47 .read = tapechar_read,
48 .write = tapechar_write,
49 .unlocked_ioctl = tapechar_ioctl,
50 #ifdef CONFIG_COMPAT
51 .compat_ioctl = tapechar_compat_ioctl,
52 #endif
53 .open = tapechar_open,
54 .release = tapechar_release,
55 .llseek = no_llseek,
56 };
57
58 static int tapechar_major = TAPECHAR_MAJOR;
59
60 /*
61 * This function is called for every new tapedevice
62 */
63 int
tapechar_setup_device(struct tape_device * device)64 tapechar_setup_device(struct tape_device * device)
65 {
66 char device_name[20];
67
68 sprintf(device_name, "ntibm%i", device->first_minor / 2);
69 device->nt = register_tape_dev(
70 &device->cdev->dev,
71 MKDEV(tapechar_major, device->first_minor),
72 &tape_fops,
73 device_name,
74 "non-rewinding"
75 );
76 device_name[0] = 'r';
77 device->rt = register_tape_dev(
78 &device->cdev->dev,
79 MKDEV(tapechar_major, device->first_minor + 1),
80 &tape_fops,
81 device_name,
82 "rewinding"
83 );
84
85 return 0;
86 }
87
88 void
tapechar_cleanup_device(struct tape_device * device)89 tapechar_cleanup_device(struct tape_device *device)
90 {
91 unregister_tape_dev(&device->cdev->dev, device->rt);
92 device->rt = NULL;
93 unregister_tape_dev(&device->cdev->dev, device->nt);
94 device->nt = NULL;
95 }
96
97 static int
tapechar_check_idalbuffer(struct tape_device * device,size_t block_size)98 tapechar_check_idalbuffer(struct tape_device *device, size_t block_size)
99 {
100 struct idal_buffer *new;
101
102 if (device->char_data.idal_buf != NULL &&
103 device->char_data.idal_buf->size == block_size)
104 return 0;
105
106 if (block_size > MAX_BLOCKSIZE) {
107 DBF_EVENT(3, "Invalid blocksize (%zd > %d)\n",
108 block_size, MAX_BLOCKSIZE);
109 return -EINVAL;
110 }
111
112 /* The current idal buffer is not correct. Allocate a new one. */
113 new = idal_buffer_alloc(block_size, 0);
114 if (IS_ERR(new))
115 return -ENOMEM;
116
117 if (device->char_data.idal_buf != NULL)
118 idal_buffer_free(device->char_data.idal_buf);
119
120 device->char_data.idal_buf = new;
121
122 return 0;
123 }
124
125 /*
126 * Tape device read function
127 */
128 static ssize_t
tapechar_read(struct file * filp,char __user * data,size_t count,loff_t * ppos)129 tapechar_read(struct file *filp, char __user *data, size_t count, loff_t *ppos)
130 {
131 struct tape_device *device;
132 struct tape_request *request;
133 size_t block_size;
134 int rc;
135
136 DBF_EVENT(6, "TCHAR:read\n");
137 device = (struct tape_device *) filp->private_data;
138
139 /*
140 * If the tape isn't terminated yet, do it now. And since we then
141 * are at the end of the tape there wouldn't be anything to read
142 * anyways. So we return immediately.
143 */
144 if(device->required_tapemarks) {
145 return tape_std_terminate_write(device);
146 }
147
148 /* Find out block size to use */
149 if (device->char_data.block_size != 0) {
150 if (count < device->char_data.block_size) {
151 DBF_EVENT(3, "TCHAR:read smaller than block "
152 "size was requested\n");
153 return -EINVAL;
154 }
155 block_size = device->char_data.block_size;
156 } else {
157 block_size = count;
158 }
159
160 rc = tapechar_check_idalbuffer(device, block_size);
161 if (rc)
162 return rc;
163
164 DBF_EVENT(6, "TCHAR:nbytes: %lx\n", block_size);
165 /* Let the discipline build the ccw chain. */
166 request = device->discipline->read_block(device, block_size);
167 if (IS_ERR(request))
168 return PTR_ERR(request);
169 /* Execute it. */
170 rc = tape_do_io(device, request);
171 if (rc == 0) {
172 rc = block_size - request->rescnt;
173 DBF_EVENT(6, "TCHAR:rbytes: %x\n", rc);
174 /* Copy data from idal buffer to user space. */
175 if (idal_buffer_to_user(device->char_data.idal_buf,
176 data, rc) != 0)
177 rc = -EFAULT;
178 }
179 tape_free_request(request);
180 return rc;
181 }
182
183 /*
184 * Tape device write function
185 */
186 static ssize_t
tapechar_write(struct file * filp,const char __user * data,size_t count,loff_t * ppos)187 tapechar_write(struct file *filp, const char __user *data, size_t count, loff_t *ppos)
188 {
189 struct tape_device *device;
190 struct tape_request *request;
191 size_t block_size;
192 size_t written;
193 int nblocks;
194 int i, rc;
195
196 DBF_EVENT(6, "TCHAR:write\n");
197 device = (struct tape_device *) filp->private_data;
198 /* Find out block size and number of blocks */
199 if (device->char_data.block_size != 0) {
200 if (count < device->char_data.block_size) {
201 DBF_EVENT(3, "TCHAR:write smaller than block "
202 "size was requested\n");
203 return -EINVAL;
204 }
205 block_size = device->char_data.block_size;
206 nblocks = count / block_size;
207 } else {
208 block_size = count;
209 nblocks = 1;
210 }
211
212 rc = tapechar_check_idalbuffer(device, block_size);
213 if (rc)
214 return rc;
215
216 DBF_EVENT(6,"TCHAR:nbytes: %lx\n", block_size);
217 DBF_EVENT(6, "TCHAR:nblocks: %x\n", nblocks);
218 /* Let the discipline build the ccw chain. */
219 request = device->discipline->write_block(device, block_size);
220 if (IS_ERR(request))
221 return PTR_ERR(request);
222 rc = 0;
223 written = 0;
224 for (i = 0; i < nblocks; i++) {
225 /* Copy data from user space to idal buffer. */
226 if (idal_buffer_from_user(device->char_data.idal_buf,
227 data, block_size)) {
228 rc = -EFAULT;
229 break;
230 }
231 rc = tape_do_io(device, request);
232 if (rc)
233 break;
234 DBF_EVENT(6, "TCHAR:wbytes: %lx\n",
235 block_size - request->rescnt);
236 written += block_size - request->rescnt;
237 if (request->rescnt != 0)
238 break;
239 data += block_size;
240 }
241 tape_free_request(request);
242 if (rc == -ENOSPC) {
243 /*
244 * Ok, the device has no more space. It has NOT written
245 * the block.
246 */
247 if (device->discipline->process_eov)
248 device->discipline->process_eov(device);
249 if (written > 0)
250 rc = 0;
251
252 }
253
254 /*
255 * After doing a write we always need two tapemarks to correctly
256 * terminate the tape (one to terminate the file, the second to
257 * flag the end of recorded data.
258 * Since process_eov positions the tape in front of the written
259 * tapemark it doesn't hurt to write two marks again.
260 */
261 if (!rc)
262 device->required_tapemarks = 2;
263
264 return rc ? rc : written;
265 }
266
267 /*
268 * Character frontend tape device open function.
269 */
270 static int
tapechar_open(struct inode * inode,struct file * filp)271 tapechar_open (struct inode *inode, struct file *filp)
272 {
273 struct tape_device *device;
274 int minor, rc;
275
276 DBF_EVENT(6, "TCHAR:open: %i:%i\n",
277 imajor(file_inode(filp)),
278 iminor(file_inode(filp)));
279
280 if (imajor(file_inode(filp)) != tapechar_major)
281 return -ENODEV;
282
283 minor = iminor(file_inode(filp));
284 device = tape_find_device(minor / TAPE_MINORS_PER_DEV);
285 if (IS_ERR(device)) {
286 DBF_EVENT(3, "TCHAR:open: tape_find_device() failed\n");
287 return PTR_ERR(device);
288 }
289
290 rc = tape_open(device);
291 if (rc == 0) {
292 filp->private_data = device;
293 stream_open(inode, filp);
294 } else
295 tape_put_device(device);
296
297 return rc;
298 }
299
300 /*
301 * Character frontend tape device release function.
302 */
303
304 static int
tapechar_release(struct inode * inode,struct file * filp)305 tapechar_release(struct inode *inode, struct file *filp)
306 {
307 struct tape_device *device;
308
309 DBF_EVENT(6, "TCHAR:release: %x\n", iminor(inode));
310 device = (struct tape_device *) filp->private_data;
311
312 /*
313 * If this is the rewinding tape minor then rewind. In that case we
314 * write all required tapemarks. Otherwise only one to terminate the
315 * file.
316 */
317 if ((iminor(inode) & 1) != 0) {
318 if (device->required_tapemarks)
319 tape_std_terminate_write(device);
320 tape_mtop(device, MTREW, 1);
321 } else {
322 if (device->required_tapemarks > 1) {
323 if (tape_mtop(device, MTWEOF, 1) == 0)
324 device->required_tapemarks--;
325 }
326 }
327
328 if (device->char_data.idal_buf != NULL) {
329 idal_buffer_free(device->char_data.idal_buf);
330 device->char_data.idal_buf = NULL;
331 }
332 tape_release(device);
333 filp->private_data = NULL;
334 tape_put_device(device);
335
336 return 0;
337 }
338
339 /*
340 * Tape device io controls.
341 */
342 static int
__tapechar_ioctl(struct tape_device * device,unsigned int no,void __user * data)343 __tapechar_ioctl(struct tape_device *device,
344 unsigned int no, void __user *data)
345 {
346 int rc;
347
348 if (no == MTIOCTOP) {
349 struct mtop op;
350
351 if (copy_from_user(&op, data, sizeof(op)) != 0)
352 return -EFAULT;
353 if (op.mt_count < 0)
354 return -EINVAL;
355
356 /*
357 * Operations that change tape position should write final
358 * tapemarks.
359 */
360 switch (op.mt_op) {
361 case MTFSF:
362 case MTBSF:
363 case MTFSR:
364 case MTBSR:
365 case MTREW:
366 case MTOFFL:
367 case MTEOM:
368 case MTRETEN:
369 case MTBSFM:
370 case MTFSFM:
371 case MTSEEK:
372 if (device->required_tapemarks)
373 tape_std_terminate_write(device);
374 }
375 rc = tape_mtop(device, op.mt_op, op.mt_count);
376
377 if (op.mt_op == MTWEOF && rc == 0) {
378 if (op.mt_count > device->required_tapemarks)
379 device->required_tapemarks = 0;
380 else
381 device->required_tapemarks -= op.mt_count;
382 }
383 return rc;
384 }
385 if (no == MTIOCPOS) {
386 /* MTIOCPOS: query the tape position. */
387 struct mtpos pos;
388
389 rc = tape_mtop(device, MTTELL, 1);
390 if (rc < 0)
391 return rc;
392 pos.mt_blkno = rc;
393 return put_user_mtpos(data, &pos);
394 }
395 if (no == MTIOCGET) {
396 /* MTIOCGET: query the tape drive status. */
397 struct mtget get;
398
399 memset(&get, 0, sizeof(get));
400 get.mt_type = MT_ISUNKNOWN;
401 get.mt_resid = 0 /* device->devstat.rescnt */;
402 get.mt_dsreg =
403 ((device->char_data.block_size << MT_ST_BLKSIZE_SHIFT)
404 & MT_ST_BLKSIZE_MASK);
405 /* FIXME: mt_gstat, mt_erreg, mt_fileno */
406 get.mt_gstat = 0;
407 get.mt_erreg = 0;
408 get.mt_fileno = 0;
409 get.mt_gstat = device->tape_generic_status;
410
411 if (device->medium_state == MS_LOADED) {
412 rc = tape_mtop(device, MTTELL, 1);
413
414 if (rc < 0)
415 return rc;
416
417 if (rc == 0)
418 get.mt_gstat |= GMT_BOT(~0);
419
420 get.mt_blkno = rc;
421 }
422
423 return put_user_mtget(data, &get);
424 }
425 /* Try the discipline ioctl function. */
426 if (device->discipline->ioctl_fn == NULL)
427 return -EINVAL;
428 return device->discipline->ioctl_fn(device, no, (unsigned long)data);
429 }
430
431 static long
tapechar_ioctl(struct file * filp,unsigned int no,unsigned long data)432 tapechar_ioctl(struct file *filp, unsigned int no, unsigned long data)
433 {
434 struct tape_device *device;
435 long rc;
436
437 DBF_EVENT(6, "TCHAR:ioct\n");
438
439 device = (struct tape_device *) filp->private_data;
440 mutex_lock(&device->mutex);
441 rc = __tapechar_ioctl(device, no, (void __user *)data);
442 mutex_unlock(&device->mutex);
443 return rc;
444 }
445
446 #ifdef CONFIG_COMPAT
447 static long
tapechar_compat_ioctl(struct file * filp,unsigned int no,unsigned long data)448 tapechar_compat_ioctl(struct file *filp, unsigned int no, unsigned long data)
449 {
450 struct tape_device *device = filp->private_data;
451 long rc;
452
453 if (no == MTIOCPOS32)
454 no = MTIOCPOS;
455 else if (no == MTIOCGET32)
456 no = MTIOCGET;
457
458 mutex_lock(&device->mutex);
459 rc = __tapechar_ioctl(device, no, compat_ptr(data));
460 mutex_unlock(&device->mutex);
461 return rc;
462 }
463 #endif /* CONFIG_COMPAT */
464
465 /*
466 * Initialize character device frontend.
467 */
468 int
tapechar_init(void)469 tapechar_init (void)
470 {
471 dev_t dev;
472
473 if (alloc_chrdev_region(&dev, 0, 256, "tape") != 0)
474 return -1;
475
476 tapechar_major = MAJOR(dev);
477
478 return 0;
479 }
480
481 /*
482 * cleanup
483 */
484 void
tapechar_exit(void)485 tapechar_exit(void)
486 {
487 unregister_chrdev_region(MKDEV(tapechar_major, 0), 256);
488 }
489