1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * storage_common.c -- Common definitions for mass storage functionality
4 *
5 * Copyright (C) 2003-2008 Alan Stern
6 * Copyeight (C) 2009 Samsung Electronics
7 * Author: Michal Nazarewicz (mina86@mina86.com)
8 */
9
10 /*
11 * This file requires the following identifiers used in USB strings to
12 * be defined (each of type pointer to char):
13 * - fsg_string_interface -- name of the interface
14 */
15
16 /*
17 * When USB_GADGET_DEBUG_FILES is defined the module param num_buffers
18 * sets the number of pipeline buffers (length of the fsg_buffhd array).
19 * The valid range of num_buffers is: num >= 2 && num <= 4.
20 */
21
22 #include <linux/module.h>
23 #include <linux/blkdev.h>
24 #include <linux/file.h>
25 #include <linux/fs.h>
26 #include <linux/usb/composite.h>
27
28 #include "storage_common.h"
29
30 /* There is only one interface. */
31
32 struct usb_interface_descriptor fsg_intf_desc = {
33 .bLength = sizeof fsg_intf_desc,
34 .bDescriptorType = USB_DT_INTERFACE,
35
36 .bNumEndpoints = 2, /* Adjusted during fsg_bind() */
37 .bInterfaceClass = USB_CLASS_MASS_STORAGE,
38 .bInterfaceSubClass = USB_SC_SCSI, /* Adjusted during fsg_bind() */
39 .bInterfaceProtocol = USB_PR_BULK, /* Adjusted during fsg_bind() */
40 .iInterface = FSG_STRING_INTERFACE,
41 };
42 EXPORT_SYMBOL_GPL(fsg_intf_desc);
43
44 /*
45 * Three full-speed endpoint descriptors: bulk-in, bulk-out, and
46 * interrupt-in.
47 */
48
49 struct usb_endpoint_descriptor fsg_fs_bulk_in_desc = {
50 .bLength = USB_DT_ENDPOINT_SIZE,
51 .bDescriptorType = USB_DT_ENDPOINT,
52
53 .bEndpointAddress = USB_DIR_IN,
54 .bmAttributes = USB_ENDPOINT_XFER_BULK,
55 /* wMaxPacketSize set by autoconfiguration */
56 };
57 EXPORT_SYMBOL_GPL(fsg_fs_bulk_in_desc);
58
59 struct usb_endpoint_descriptor fsg_fs_bulk_out_desc = {
60 .bLength = USB_DT_ENDPOINT_SIZE,
61 .bDescriptorType = USB_DT_ENDPOINT,
62
63 .bEndpointAddress = USB_DIR_OUT,
64 .bmAttributes = USB_ENDPOINT_XFER_BULK,
65 /* wMaxPacketSize set by autoconfiguration */
66 };
67 EXPORT_SYMBOL_GPL(fsg_fs_bulk_out_desc);
68
69 struct usb_descriptor_header *fsg_fs_function[] = {
70 (struct usb_descriptor_header *) &fsg_intf_desc,
71 (struct usb_descriptor_header *) &fsg_fs_bulk_in_desc,
72 (struct usb_descriptor_header *) &fsg_fs_bulk_out_desc,
73 NULL,
74 };
75 EXPORT_SYMBOL_GPL(fsg_fs_function);
76
77
78 /*
79 * USB 2.0 devices need to expose both high speed and full speed
80 * descriptors, unless they only run at full speed.
81 *
82 * That means alternate endpoint descriptors (bigger packets).
83 */
84 struct usb_endpoint_descriptor fsg_hs_bulk_in_desc = {
85 .bLength = USB_DT_ENDPOINT_SIZE,
86 .bDescriptorType = USB_DT_ENDPOINT,
87
88 /* bEndpointAddress copied from fs_bulk_in_desc during fsg_bind() */
89 .bmAttributes = USB_ENDPOINT_XFER_BULK,
90 .wMaxPacketSize = cpu_to_le16(512),
91 };
92 EXPORT_SYMBOL_GPL(fsg_hs_bulk_in_desc);
93
94 struct usb_endpoint_descriptor fsg_hs_bulk_out_desc = {
95 .bLength = USB_DT_ENDPOINT_SIZE,
96 .bDescriptorType = USB_DT_ENDPOINT,
97
98 /* bEndpointAddress copied from fs_bulk_out_desc during fsg_bind() */
99 .bmAttributes = USB_ENDPOINT_XFER_BULK,
100 .wMaxPacketSize = cpu_to_le16(512),
101 .bInterval = 1, /* NAK every 1 uframe */
102 };
103 EXPORT_SYMBOL_GPL(fsg_hs_bulk_out_desc);
104
105
106 struct usb_descriptor_header *fsg_hs_function[] = {
107 (struct usb_descriptor_header *) &fsg_intf_desc,
108 (struct usb_descriptor_header *) &fsg_hs_bulk_in_desc,
109 (struct usb_descriptor_header *) &fsg_hs_bulk_out_desc,
110 NULL,
111 };
112 EXPORT_SYMBOL_GPL(fsg_hs_function);
113
114 struct usb_endpoint_descriptor fsg_ss_bulk_in_desc = {
115 .bLength = USB_DT_ENDPOINT_SIZE,
116 .bDescriptorType = USB_DT_ENDPOINT,
117
118 /* bEndpointAddress copied from fs_bulk_in_desc during fsg_bind() */
119 .bmAttributes = USB_ENDPOINT_XFER_BULK,
120 .wMaxPacketSize = cpu_to_le16(1024),
121 };
122 EXPORT_SYMBOL_GPL(fsg_ss_bulk_in_desc);
123
124 struct usb_ss_ep_comp_descriptor fsg_ss_bulk_in_comp_desc = {
125 .bLength = sizeof(fsg_ss_bulk_in_comp_desc),
126 .bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
127
128 /*.bMaxBurst = DYNAMIC, */
129 };
130 EXPORT_SYMBOL_GPL(fsg_ss_bulk_in_comp_desc);
131
132 struct usb_endpoint_descriptor fsg_ss_bulk_out_desc = {
133 .bLength = USB_DT_ENDPOINT_SIZE,
134 .bDescriptorType = USB_DT_ENDPOINT,
135
136 /* bEndpointAddress copied from fs_bulk_out_desc during fsg_bind() */
137 .bmAttributes = USB_ENDPOINT_XFER_BULK,
138 .wMaxPacketSize = cpu_to_le16(1024),
139 };
140 EXPORT_SYMBOL_GPL(fsg_ss_bulk_out_desc);
141
142 struct usb_ss_ep_comp_descriptor fsg_ss_bulk_out_comp_desc = {
143 .bLength = sizeof(fsg_ss_bulk_in_comp_desc),
144 .bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
145
146 /*.bMaxBurst = DYNAMIC, */
147 };
148 EXPORT_SYMBOL_GPL(fsg_ss_bulk_out_comp_desc);
149
150 struct usb_descriptor_header *fsg_ss_function[] = {
151 (struct usb_descriptor_header *) &fsg_intf_desc,
152 (struct usb_descriptor_header *) &fsg_ss_bulk_in_desc,
153 (struct usb_descriptor_header *) &fsg_ss_bulk_in_comp_desc,
154 (struct usb_descriptor_header *) &fsg_ss_bulk_out_desc,
155 (struct usb_descriptor_header *) &fsg_ss_bulk_out_comp_desc,
156 NULL,
157 };
158 EXPORT_SYMBOL_GPL(fsg_ss_function);
159
160
161 /*-------------------------------------------------------------------------*/
162
163 /*
164 * If the next two routines are called while the gadget is registered,
165 * the caller must own fsg->filesem for writing.
166 */
167
fsg_lun_close(struct fsg_lun * curlun)168 void fsg_lun_close(struct fsg_lun *curlun)
169 {
170 if (curlun->filp) {
171 LDBG(curlun, "close backing file\n");
172 fput(curlun->filp);
173 curlun->filp = NULL;
174 }
175 }
176 EXPORT_SYMBOL_GPL(fsg_lun_close);
177
fsg_lun_open(struct fsg_lun * curlun,const char * filename)178 int fsg_lun_open(struct fsg_lun *curlun, const char *filename)
179 {
180 int ro;
181 struct file *filp = NULL;
182 int rc = -EINVAL;
183 struct inode *inode = NULL;
184 loff_t size;
185 loff_t num_sectors;
186 loff_t min_sectors;
187 unsigned int blkbits;
188 unsigned int blksize;
189
190 /* R/W if we can, R/O if we must */
191 ro = curlun->initially_ro;
192 if (!ro) {
193 filp = filp_open(filename, O_RDWR | O_LARGEFILE, 0);
194 if (PTR_ERR(filp) == -EROFS || PTR_ERR(filp) == -EACCES)
195 ro = 1;
196 }
197 if (ro)
198 filp = filp_open(filename, O_RDONLY | O_LARGEFILE, 0);
199 if (IS_ERR(filp)) {
200 LINFO(curlun, "unable to open backing file: %s\n", filename);
201 return PTR_ERR(filp);
202 }
203
204 if (!(filp->f_mode & FMODE_WRITE))
205 ro = 1;
206
207 inode = file_inode(filp);
208 if ((!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode))) {
209 LINFO(curlun, "invalid file type: %s\n", filename);
210 goto out;
211 }
212
213 /*
214 * If we can't read the file, it's no good.
215 * If we can't write the file, use it read-only.
216 */
217 if (!(filp->f_mode & FMODE_CAN_READ)) {
218 LINFO(curlun, "file not readable: %s\n", filename);
219 goto out;
220 }
221 if (!(filp->f_mode & FMODE_CAN_WRITE))
222 ro = 1;
223
224 size = i_size_read(inode->i_mapping->host);
225 if (size < 0) {
226 LINFO(curlun, "unable to find file size: %s\n", filename);
227 rc = (int) size;
228 goto out;
229 }
230
231 if (curlun->cdrom) {
232 blksize = 2048;
233 blkbits = 11;
234 } else if (inode->i_bdev) {
235 blksize = bdev_logical_block_size(inode->i_bdev);
236 blkbits = blksize_bits(blksize);
237 } else {
238 blksize = 512;
239 blkbits = 9;
240 }
241
242 num_sectors = size >> blkbits; /* File size in logic-block-size blocks */
243 min_sectors = 1;
244 if (curlun->cdrom) {
245 min_sectors = 300; /* Smallest track is 300 frames */
246 if (num_sectors >= 256*60*75) {
247 num_sectors = 256*60*75 - 1;
248 LINFO(curlun, "file too big: %s\n", filename);
249 LINFO(curlun, "using only first %d blocks\n",
250 (int) num_sectors);
251 }
252 }
253 if (num_sectors < min_sectors) {
254 LINFO(curlun, "file too small: %s\n", filename);
255 rc = -ETOOSMALL;
256 goto out;
257 }
258
259 if (fsg_lun_is_open(curlun))
260 fsg_lun_close(curlun);
261
262 curlun->blksize = blksize;
263 curlun->blkbits = blkbits;
264 curlun->ro = ro;
265 curlun->filp = filp;
266 curlun->file_length = size;
267 curlun->num_sectors = num_sectors;
268 LDBG(curlun, "open backing file: %s\n", filename);
269 return 0;
270
271 out:
272 fput(filp);
273 return rc;
274 }
275 EXPORT_SYMBOL_GPL(fsg_lun_open);
276
277
278 /*-------------------------------------------------------------------------*/
279
280 /*
281 * Sync the file data, don't bother with the metadata.
282 * This code was copied from fs/buffer.c:sys_fdatasync().
283 */
fsg_lun_fsync_sub(struct fsg_lun * curlun)284 int fsg_lun_fsync_sub(struct fsg_lun *curlun)
285 {
286 struct file *filp = curlun->filp;
287
288 if (curlun->ro || !filp)
289 return 0;
290 return vfs_fsync(filp, 1);
291 }
292 EXPORT_SYMBOL_GPL(fsg_lun_fsync_sub);
293
store_cdrom_address(u8 * dest,int msf,u32 addr)294 void store_cdrom_address(u8 *dest, int msf, u32 addr)
295 {
296 if (msf) {
297 /* Convert to Minutes-Seconds-Frames */
298 addr >>= 2; /* Convert to 2048-byte frames */
299 addr += 2*75; /* Lead-in occupies 2 seconds */
300 dest[3] = addr % 75; /* Frames */
301 addr /= 75;
302 dest[2] = addr % 60; /* Seconds */
303 addr /= 60;
304 dest[1] = addr; /* Minutes */
305 dest[0] = 0; /* Reserved */
306 } else {
307 /* Absolute sector */
308 put_unaligned_be32(addr, dest);
309 }
310 }
311 EXPORT_SYMBOL_GPL(store_cdrom_address);
312
313 /*-------------------------------------------------------------------------*/
314
315
fsg_show_ro(struct fsg_lun * curlun,char * buf)316 ssize_t fsg_show_ro(struct fsg_lun *curlun, char *buf)
317 {
318 return sprintf(buf, "%d\n", fsg_lun_is_open(curlun)
319 ? curlun->ro
320 : curlun->initially_ro);
321 }
322 EXPORT_SYMBOL_GPL(fsg_show_ro);
323
fsg_show_nofua(struct fsg_lun * curlun,char * buf)324 ssize_t fsg_show_nofua(struct fsg_lun *curlun, char *buf)
325 {
326 return sprintf(buf, "%u\n", curlun->nofua);
327 }
328 EXPORT_SYMBOL_GPL(fsg_show_nofua);
329
fsg_show_file(struct fsg_lun * curlun,struct rw_semaphore * filesem,char * buf)330 ssize_t fsg_show_file(struct fsg_lun *curlun, struct rw_semaphore *filesem,
331 char *buf)
332 {
333 char *p;
334 ssize_t rc;
335
336 down_read(filesem);
337 if (fsg_lun_is_open(curlun)) { /* Get the complete pathname */
338 p = file_path(curlun->filp, buf, PAGE_SIZE - 1);
339 if (IS_ERR(p))
340 rc = PTR_ERR(p);
341 else {
342 rc = strlen(p);
343 memmove(buf, p, rc);
344 buf[rc] = '\n'; /* Add a newline */
345 buf[++rc] = 0;
346 }
347 } else { /* No file, return 0 bytes */
348 *buf = 0;
349 rc = 0;
350 }
351 up_read(filesem);
352 return rc;
353 }
354 EXPORT_SYMBOL_GPL(fsg_show_file);
355
fsg_show_cdrom(struct fsg_lun * curlun,char * buf)356 ssize_t fsg_show_cdrom(struct fsg_lun *curlun, char *buf)
357 {
358 return sprintf(buf, "%u\n", curlun->cdrom);
359 }
360 EXPORT_SYMBOL_GPL(fsg_show_cdrom);
361
fsg_show_removable(struct fsg_lun * curlun,char * buf)362 ssize_t fsg_show_removable(struct fsg_lun *curlun, char *buf)
363 {
364 return sprintf(buf, "%u\n", curlun->removable);
365 }
366 EXPORT_SYMBOL_GPL(fsg_show_removable);
367
fsg_show_inquiry_string(struct fsg_lun * curlun,char * buf)368 ssize_t fsg_show_inquiry_string(struct fsg_lun *curlun, char *buf)
369 {
370 return sprintf(buf, "%s\n", curlun->inquiry_string);
371 }
372 EXPORT_SYMBOL_GPL(fsg_show_inquiry_string);
373
374 /*
375 * The caller must hold fsg->filesem for reading when calling this function.
376 */
_fsg_store_ro(struct fsg_lun * curlun,bool ro)377 static ssize_t _fsg_store_ro(struct fsg_lun *curlun, bool ro)
378 {
379 if (fsg_lun_is_open(curlun)) {
380 LDBG(curlun, "read-only status change prevented\n");
381 return -EBUSY;
382 }
383
384 curlun->ro = ro;
385 curlun->initially_ro = ro;
386 LDBG(curlun, "read-only status set to %d\n", curlun->ro);
387
388 return 0;
389 }
390
fsg_store_ro(struct fsg_lun * curlun,struct rw_semaphore * filesem,const char * buf,size_t count)391 ssize_t fsg_store_ro(struct fsg_lun *curlun, struct rw_semaphore *filesem,
392 const char *buf, size_t count)
393 {
394 ssize_t rc;
395 bool ro;
396
397 rc = strtobool(buf, &ro);
398 if (rc)
399 return rc;
400
401 /*
402 * Allow the write-enable status to change only while the
403 * backing file is closed.
404 */
405 down_read(filesem);
406 rc = _fsg_store_ro(curlun, ro);
407 if (!rc)
408 rc = count;
409 up_read(filesem);
410
411 return rc;
412 }
413 EXPORT_SYMBOL_GPL(fsg_store_ro);
414
fsg_store_nofua(struct fsg_lun * curlun,const char * buf,size_t count)415 ssize_t fsg_store_nofua(struct fsg_lun *curlun, const char *buf, size_t count)
416 {
417 bool nofua;
418 int ret;
419
420 ret = strtobool(buf, &nofua);
421 if (ret)
422 return ret;
423
424 /* Sync data when switching from async mode to sync */
425 if (!nofua && curlun->nofua)
426 fsg_lun_fsync_sub(curlun);
427
428 curlun->nofua = nofua;
429
430 return count;
431 }
432 EXPORT_SYMBOL_GPL(fsg_store_nofua);
433
fsg_store_file(struct fsg_lun * curlun,struct rw_semaphore * filesem,const char * buf,size_t count)434 ssize_t fsg_store_file(struct fsg_lun *curlun, struct rw_semaphore *filesem,
435 const char *buf, size_t count)
436 {
437 int rc = 0;
438
439 if (curlun->prevent_medium_removal && fsg_lun_is_open(curlun)) {
440 LDBG(curlun, "eject attempt prevented\n");
441 return -EBUSY; /* "Door is locked" */
442 }
443
444 /* Remove a trailing newline */
445 if (count > 0 && buf[count-1] == '\n')
446 ((char *) buf)[count-1] = 0; /* Ugh! */
447
448 /* Load new medium */
449 down_write(filesem);
450 if (count > 0 && buf[0]) {
451 /* fsg_lun_open() will close existing file if any. */
452 rc = fsg_lun_open(curlun, buf);
453 if (rc == 0)
454 curlun->unit_attention_data =
455 SS_NOT_READY_TO_READY_TRANSITION;
456 } else if (fsg_lun_is_open(curlun)) {
457 fsg_lun_close(curlun);
458 curlun->unit_attention_data = SS_MEDIUM_NOT_PRESENT;
459 }
460 up_write(filesem);
461 return (rc < 0 ? rc : count);
462 }
463 EXPORT_SYMBOL_GPL(fsg_store_file);
464
fsg_store_cdrom(struct fsg_lun * curlun,struct rw_semaphore * filesem,const char * buf,size_t count)465 ssize_t fsg_store_cdrom(struct fsg_lun *curlun, struct rw_semaphore *filesem,
466 const char *buf, size_t count)
467 {
468 bool cdrom;
469 int ret;
470
471 ret = strtobool(buf, &cdrom);
472 if (ret)
473 return ret;
474
475 down_read(filesem);
476 ret = cdrom ? _fsg_store_ro(curlun, true) : 0;
477
478 if (!ret) {
479 curlun->cdrom = cdrom;
480 ret = count;
481 }
482 up_read(filesem);
483
484 return ret;
485 }
486 EXPORT_SYMBOL_GPL(fsg_store_cdrom);
487
fsg_store_removable(struct fsg_lun * curlun,const char * buf,size_t count)488 ssize_t fsg_store_removable(struct fsg_lun *curlun, const char *buf,
489 size_t count)
490 {
491 bool removable;
492 int ret;
493
494 ret = strtobool(buf, &removable);
495 if (ret)
496 return ret;
497
498 curlun->removable = removable;
499
500 return count;
501 }
502 EXPORT_SYMBOL_GPL(fsg_store_removable);
503
fsg_store_inquiry_string(struct fsg_lun * curlun,const char * buf,size_t count)504 ssize_t fsg_store_inquiry_string(struct fsg_lun *curlun, const char *buf,
505 size_t count)
506 {
507 const size_t len = min(count, sizeof(curlun->inquiry_string));
508
509 if (len == 0 || buf[0] == '\n') {
510 curlun->inquiry_string[0] = 0;
511 } else {
512 snprintf(curlun->inquiry_string,
513 sizeof(curlun->inquiry_string), "%-28s", buf);
514 if (curlun->inquiry_string[len-1] == '\n')
515 curlun->inquiry_string[len-1] = ' ';
516 }
517
518 return count;
519 }
520 EXPORT_SYMBOL_GPL(fsg_store_inquiry_string);
521
522 MODULE_LICENSE("GPL");
523
