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 |
64 | tapechar_setup_device(struct tape_device * device) |
65 | { |
66 | char device_name[20]; |
67 | |
68 | sprintf(buf: device_name, fmt: "ntibm%i" , device->first_minor / 2); |
69 | device->nt = register_tape_dev( |
70 | device: &device->cdev->dev, |
71 | MKDEV(tapechar_major, device->first_minor), |
72 | fops: &tape_fops, |
73 | device_name, |
74 | node_name: "non-rewinding" |
75 | ); |
76 | device_name[0] = 'r'; |
77 | device->rt = register_tape_dev( |
78 | device: &device->cdev->dev, |
79 | MKDEV(tapechar_major, device->first_minor + 1), |
80 | fops: &tape_fops, |
81 | device_name, |
82 | node_name: "rewinding" |
83 | ); |
84 | |
85 | return 0; |
86 | } |
87 | |
88 | void |
89 | tapechar_cleanup_device(struct tape_device *device) |
90 | { |
91 | unregister_tape_dev(device: &device->cdev->dev, tcd: device->rt); |
92 | device->rt = NULL; |
93 | unregister_tape_dev(device: &device->cdev->dev, tcd: device->nt); |
94 | device->nt = NULL; |
95 | } |
96 | |
97 | static int |
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(ptr: 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 |
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(ptr: request)) |
168 | return PTR_ERR(ptr: 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 |
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(ptr: request)) |
221 | return PTR_ERR(ptr: 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 |
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(inode: file_inode(f: filp)) != tapechar_major) |
281 | return -ENODEV; |
282 | |
283 | minor = iminor(inode: file_inode(f: filp)); |
284 | device = tape_find_device(devindex: minor / TAPE_MINORS_PER_DEV); |
285 | if (IS_ERR(ptr: device)) { |
286 | DBF_EVENT(3, "TCHAR:open: tape_find_device() failed\n" ); |
287 | return PTR_ERR(ptr: 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 |
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 |
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(to: &op, from: data, n: 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(u: data, k: &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(u: data, k: &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 |
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, data: (void __user *)data); |
442 | mutex_unlock(lock: &device->mutex); |
443 | return rc; |
444 | } |
445 | |
446 | #ifdef CONFIG_COMPAT |
447 | static long |
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, data: compat_ptr(uptr: data)); |
460 | mutex_unlock(lock: &device->mutex); |
461 | return rc; |
462 | } |
463 | #endif /* CONFIG_COMPAT */ |
464 | |
465 | /* |
466 | * Initialize character device frontend. |
467 | */ |
468 | int |
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 |
485 | tapechar_exit(void) |
486 | { |
487 | unregister_chrdev_region(MKDEV(tapechar_major, 0), 256); |
488 | } |
489 | |