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