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/kstrtox.h>
27#include <linux/usb/composite.h>
28
29#include "storage_common.h"
30
31/* There is only one interface. */
32
33struct usb_interface_descriptor fsg_intf_desc = {
34 .bLength = sizeof fsg_intf_desc,
35 .bDescriptorType = USB_DT_INTERFACE,
36
37 .bNumEndpoints = 2, /* Adjusted during fsg_bind() */
38 .bInterfaceClass = USB_CLASS_MASS_STORAGE,
39 .bInterfaceSubClass = USB_SC_SCSI, /* Adjusted during fsg_bind() */
40 .bInterfaceProtocol = USB_PR_BULK, /* Adjusted during fsg_bind() */
41 .iInterface = FSG_STRING_INTERFACE,
42};
43EXPORT_SYMBOL_GPL(fsg_intf_desc);
44
45/*
46 * Three full-speed endpoint descriptors: bulk-in, bulk-out, and
47 * interrupt-in.
48 */
49
50struct usb_endpoint_descriptor fsg_fs_bulk_in_desc = {
51 .bLength = USB_DT_ENDPOINT_SIZE,
52 .bDescriptorType = USB_DT_ENDPOINT,
53
54 .bEndpointAddress = USB_DIR_IN,
55 .bmAttributes = USB_ENDPOINT_XFER_BULK,
56 /* wMaxPacketSize set by autoconfiguration */
57};
58EXPORT_SYMBOL_GPL(fsg_fs_bulk_in_desc);
59
60struct usb_endpoint_descriptor fsg_fs_bulk_out_desc = {
61 .bLength = USB_DT_ENDPOINT_SIZE,
62 .bDescriptorType = USB_DT_ENDPOINT,
63
64 .bEndpointAddress = USB_DIR_OUT,
65 .bmAttributes = USB_ENDPOINT_XFER_BULK,
66 /* wMaxPacketSize set by autoconfiguration */
67};
68EXPORT_SYMBOL_GPL(fsg_fs_bulk_out_desc);
69
70struct usb_descriptor_header *fsg_fs_function[] = {
71 (struct usb_descriptor_header *) &fsg_intf_desc,
72 (struct usb_descriptor_header *) &fsg_fs_bulk_in_desc,
73 (struct usb_descriptor_header *) &fsg_fs_bulk_out_desc,
74 NULL,
75};
76EXPORT_SYMBOL_GPL(fsg_fs_function);
77
78
79/*
80 * USB 2.0 devices need to expose both high speed and full speed
81 * descriptors, unless they only run at full speed.
82 *
83 * That means alternate endpoint descriptors (bigger packets).
84 */
85struct usb_endpoint_descriptor fsg_hs_bulk_in_desc = {
86 .bLength = USB_DT_ENDPOINT_SIZE,
87 .bDescriptorType = USB_DT_ENDPOINT,
88
89 /* bEndpointAddress copied from fs_bulk_in_desc during fsg_bind() */
90 .bmAttributes = USB_ENDPOINT_XFER_BULK,
91 .wMaxPacketSize = cpu_to_le16(512),
92};
93EXPORT_SYMBOL_GPL(fsg_hs_bulk_in_desc);
94
95struct usb_endpoint_descriptor fsg_hs_bulk_out_desc = {
96 .bLength = USB_DT_ENDPOINT_SIZE,
97 .bDescriptorType = USB_DT_ENDPOINT,
98
99 /* bEndpointAddress copied from fs_bulk_out_desc during fsg_bind() */
100 .bmAttributes = USB_ENDPOINT_XFER_BULK,
101 .wMaxPacketSize = cpu_to_le16(512),
102 .bInterval = 1, /* NAK every 1 uframe */
103};
104EXPORT_SYMBOL_GPL(fsg_hs_bulk_out_desc);
105
106
107struct usb_descriptor_header *fsg_hs_function[] = {
108 (struct usb_descriptor_header *) &fsg_intf_desc,
109 (struct usb_descriptor_header *) &fsg_hs_bulk_in_desc,
110 (struct usb_descriptor_header *) &fsg_hs_bulk_out_desc,
111 NULL,
112};
113EXPORT_SYMBOL_GPL(fsg_hs_function);
114
115struct usb_endpoint_descriptor fsg_ss_bulk_in_desc = {
116 .bLength = USB_DT_ENDPOINT_SIZE,
117 .bDescriptorType = USB_DT_ENDPOINT,
118
119 /* bEndpointAddress copied from fs_bulk_in_desc during fsg_bind() */
120 .bmAttributes = USB_ENDPOINT_XFER_BULK,
121 .wMaxPacketSize = cpu_to_le16(1024),
122};
123EXPORT_SYMBOL_GPL(fsg_ss_bulk_in_desc);
124
125struct usb_ss_ep_comp_descriptor fsg_ss_bulk_in_comp_desc = {
126 .bLength = sizeof(fsg_ss_bulk_in_comp_desc),
127 .bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
128
129 /*.bMaxBurst = DYNAMIC, */
130};
131EXPORT_SYMBOL_GPL(fsg_ss_bulk_in_comp_desc);
132
133struct usb_endpoint_descriptor fsg_ss_bulk_out_desc = {
134 .bLength = USB_DT_ENDPOINT_SIZE,
135 .bDescriptorType = USB_DT_ENDPOINT,
136
137 /* bEndpointAddress copied from fs_bulk_out_desc during fsg_bind() */
138 .bmAttributes = USB_ENDPOINT_XFER_BULK,
139 .wMaxPacketSize = cpu_to_le16(1024),
140};
141EXPORT_SYMBOL_GPL(fsg_ss_bulk_out_desc);
142
143struct usb_ss_ep_comp_descriptor fsg_ss_bulk_out_comp_desc = {
144 .bLength = sizeof(fsg_ss_bulk_in_comp_desc),
145 .bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
146
147 /*.bMaxBurst = DYNAMIC, */
148};
149EXPORT_SYMBOL_GPL(fsg_ss_bulk_out_comp_desc);
150
151struct usb_descriptor_header *fsg_ss_function[] = {
152 (struct usb_descriptor_header *) &fsg_intf_desc,
153 (struct usb_descriptor_header *) &fsg_ss_bulk_in_desc,
154 (struct usb_descriptor_header *) &fsg_ss_bulk_in_comp_desc,
155 (struct usb_descriptor_header *) &fsg_ss_bulk_out_desc,
156 (struct usb_descriptor_header *) &fsg_ss_bulk_out_comp_desc,
157 NULL,
158};
159EXPORT_SYMBOL_GPL(fsg_ss_function);
160
161
162 /*-------------------------------------------------------------------------*/
163
164/*
165 * If the next two routines are called while the gadget is registered,
166 * the caller must own fsg->filesem for writing.
167 */
168
169void fsg_lun_close(struct fsg_lun *curlun)
170{
171 if (curlun->filp) {
172 LDBG(curlun, "close backing file\n");
173 fput(curlun->filp);
174 curlun->filp = NULL;
175 }
176}
177EXPORT_SYMBOL_GPL(fsg_lun_close);
178
179int fsg_lun_open(struct fsg_lun *curlun, const char *filename)
180{
181 int ro;
182 struct file *filp = NULL;
183 int rc = -EINVAL;
184 struct inode *inode = NULL;
185 loff_t size;
186 loff_t num_sectors;
187 loff_t min_sectors;
188 unsigned int blkbits;
189 unsigned int blksize;
190
191 /* R/W if we can, R/O if we must */
192 ro = curlun->initially_ro;
193 if (!ro) {
194 filp = filp_open(filename, O_RDWR | O_LARGEFILE, 0);
195 if (PTR_ERR(ptr: filp) == -EROFS || PTR_ERR(ptr: filp) == -EACCES)
196 ro = 1;
197 }
198 if (ro)
199 filp = filp_open(filename, O_RDONLY | O_LARGEFILE, 0);
200 if (IS_ERR(ptr: filp)) {
201 LINFO(curlun, "unable to open backing file: %s\n", filename);
202 return PTR_ERR(ptr: filp);
203 }
204
205 if (!(filp->f_mode & FMODE_WRITE))
206 ro = 1;
207
208 inode = filp->f_mapping->host;
209 if ((!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode))) {
210 LINFO(curlun, "invalid file type: %s\n", filename);
211 goto out;
212 }
213
214 /*
215 * If we can't read the file, it's no good.
216 * If we can't write the file, use it read-only.
217 */
218 if (!(filp->f_mode & FMODE_CAN_READ)) {
219 LINFO(curlun, "file not readable: %s\n", filename);
220 goto out;
221 }
222 if (!(filp->f_mode & FMODE_CAN_WRITE))
223 ro = 1;
224
225 size = i_size_read(inode);
226 if (size < 0) {
227 LINFO(curlun, "unable to find file size: %s\n", filename);
228 rc = (int) size;
229 goto out;
230 }
231
232 if (curlun->cdrom) {
233 blksize = 2048;
234 blkbits = 11;
235 } else if (S_ISBLK(inode->i_mode)) {
236 blksize = bdev_logical_block_size(bdev: I_BDEV(inode));
237 blkbits = blksize_bits(size: blksize);
238 } else {
239 blksize = 512;
240 blkbits = 9;
241 }
242
243 num_sectors = size >> blkbits; /* File size in logic-block-size blocks */
244 min_sectors = 1;
245 if (curlun->cdrom) {
246 min_sectors = 300; /* Smallest track is 300 frames */
247 if (num_sectors >= 256*60*75) {
248 num_sectors = 256*60*75 - 1;
249 LINFO(curlun, "file too big: %s\n", filename);
250 LINFO(curlun, "using only first %d blocks\n",
251 (int) num_sectors);
252 }
253 }
254 if (num_sectors < min_sectors) {
255 LINFO(curlun, "file too small: %s\n", filename);
256 rc = -ETOOSMALL;
257 goto out;
258 }
259
260 if (fsg_lun_is_open(curlun))
261 fsg_lun_close(curlun);
262
263 curlun->blksize = blksize;
264 curlun->blkbits = blkbits;
265 curlun->ro = ro;
266 curlun->filp = filp;
267 curlun->file_length = size;
268 curlun->num_sectors = num_sectors;
269 LDBG(curlun, "open backing file: %s\n", filename);
270 return 0;
271
272out:
273 fput(filp);
274 return rc;
275}
276EXPORT_SYMBOL_GPL(fsg_lun_open);
277
278
279/*-------------------------------------------------------------------------*/
280
281/*
282 * Sync the file data, don't bother with the metadata.
283 * This code was copied from fs/buffer.c:sys_fdatasync().
284 */
285int fsg_lun_fsync_sub(struct fsg_lun *curlun)
286{
287 struct file *filp = curlun->filp;
288
289 if (curlun->ro || !filp)
290 return 0;
291 return vfs_fsync(file: filp, datasync: 1);
292}
293EXPORT_SYMBOL_GPL(fsg_lun_fsync_sub);
294
295void store_cdrom_address(u8 *dest, int msf, u32 addr)
296{
297 if (msf) {
298 /*
299 * Convert to Minutes-Seconds-Frames.
300 * Sector size is already set to 2048 bytes.
301 */
302 addr += 2*75; /* Lead-in occupies 2 seconds */
303 dest[3] = addr % 75; /* Frames */
304 addr /= 75;
305 dest[2] = addr % 60; /* Seconds */
306 addr /= 60;
307 dest[1] = addr; /* Minutes */
308 dest[0] = 0; /* Reserved */
309 } else {
310 /* Absolute sector */
311 put_unaligned_be32(val: addr, p: dest);
312 }
313}
314EXPORT_SYMBOL_GPL(store_cdrom_address);
315
316/*-------------------------------------------------------------------------*/
317
318
319ssize_t fsg_show_ro(struct fsg_lun *curlun, char *buf)
320{
321 return sprintf(buf, fmt: "%d\n", fsg_lun_is_open(curlun)
322 ? curlun->ro
323 : curlun->initially_ro);
324}
325EXPORT_SYMBOL_GPL(fsg_show_ro);
326
327ssize_t fsg_show_nofua(struct fsg_lun *curlun, char *buf)
328{
329 return sprintf(buf, fmt: "%u\n", curlun->nofua);
330}
331EXPORT_SYMBOL_GPL(fsg_show_nofua);
332
333ssize_t fsg_show_file(struct fsg_lun *curlun, struct rw_semaphore *filesem,
334 char *buf)
335{
336 char *p;
337 ssize_t rc;
338
339 down_read(sem: filesem);
340 if (fsg_lun_is_open(curlun)) { /* Get the complete pathname */
341 p = file_path(curlun->filp, buf, PAGE_SIZE - 1);
342 if (IS_ERR(ptr: p))
343 rc = PTR_ERR(ptr: p);
344 else {
345 rc = strlen(p);
346 memmove(buf, p, rc);
347 buf[rc] = '\n'; /* Add a newline */
348 buf[++rc] = 0;
349 }
350 } else { /* No file, return 0 bytes */
351 *buf = 0;
352 rc = 0;
353 }
354 up_read(sem: filesem);
355 return rc;
356}
357EXPORT_SYMBOL_GPL(fsg_show_file);
358
359ssize_t fsg_show_cdrom(struct fsg_lun *curlun, char *buf)
360{
361 return sprintf(buf, fmt: "%u\n", curlun->cdrom);
362}
363EXPORT_SYMBOL_GPL(fsg_show_cdrom);
364
365ssize_t fsg_show_removable(struct fsg_lun *curlun, char *buf)
366{
367 return sprintf(buf, fmt: "%u\n", curlun->removable);
368}
369EXPORT_SYMBOL_GPL(fsg_show_removable);
370
371ssize_t fsg_show_inquiry_string(struct fsg_lun *curlun, char *buf)
372{
373 return sprintf(buf, fmt: "%s\n", curlun->inquiry_string);
374}
375EXPORT_SYMBOL_GPL(fsg_show_inquiry_string);
376
377/*
378 * The caller must hold fsg->filesem for reading when calling this function.
379 */
380static ssize_t _fsg_store_ro(struct fsg_lun *curlun, bool ro)
381{
382 if (fsg_lun_is_open(curlun)) {
383 LDBG(curlun, "read-only status change prevented\n");
384 return -EBUSY;
385 }
386
387 curlun->ro = ro;
388 curlun->initially_ro = ro;
389 LDBG(curlun, "read-only status set to %d\n", curlun->ro);
390
391 return 0;
392}
393
394ssize_t fsg_store_ro(struct fsg_lun *curlun, struct rw_semaphore *filesem,
395 const char *buf, size_t count)
396{
397 ssize_t rc;
398 bool ro;
399
400 rc = kstrtobool(s: buf, res: &ro);
401 if (rc)
402 return rc;
403
404 /*
405 * Allow the write-enable status to change only while the
406 * backing file is closed.
407 */
408 down_read(sem: filesem);
409 rc = _fsg_store_ro(curlun, ro);
410 if (!rc)
411 rc = count;
412 up_read(sem: filesem);
413
414 return rc;
415}
416EXPORT_SYMBOL_GPL(fsg_store_ro);
417
418ssize_t fsg_store_nofua(struct fsg_lun *curlun, const char *buf, size_t count)
419{
420 bool nofua;
421 int ret;
422
423 ret = kstrtobool(s: buf, res: &nofua);
424 if (ret)
425 return ret;
426
427 /* Sync data when switching from async mode to sync */
428 if (!nofua && curlun->nofua)
429 fsg_lun_fsync_sub(curlun);
430
431 curlun->nofua = nofua;
432
433 return count;
434}
435EXPORT_SYMBOL_GPL(fsg_store_nofua);
436
437ssize_t fsg_store_file(struct fsg_lun *curlun, struct rw_semaphore *filesem,
438 const char *buf, size_t count)
439{
440 int rc = 0;
441
442 if (curlun->prevent_medium_removal && fsg_lun_is_open(curlun)) {
443 LDBG(curlun, "eject attempt prevented\n");
444 return -EBUSY; /* "Door is locked" */
445 }
446
447 /* Remove a trailing newline */
448 if (count > 0 && buf[count-1] == '\n')
449 ((char *) buf)[count-1] = 0; /* Ugh! */
450
451 /* Load new medium */
452 down_write(sem: filesem);
453 if (count > 0 && buf[0]) {
454 /* fsg_lun_open() will close existing file if any. */
455 rc = fsg_lun_open(curlun, buf);
456 if (rc == 0)
457 curlun->unit_attention_data =
458 SS_NOT_READY_TO_READY_TRANSITION;
459 } else if (fsg_lun_is_open(curlun)) {
460 fsg_lun_close(curlun);
461 curlun->unit_attention_data = SS_MEDIUM_NOT_PRESENT;
462 }
463 up_write(sem: filesem);
464 return (rc < 0 ? rc : count);
465}
466EXPORT_SYMBOL_GPL(fsg_store_file);
467
468ssize_t fsg_store_cdrom(struct fsg_lun *curlun, struct rw_semaphore *filesem,
469 const char *buf, size_t count)
470{
471 bool cdrom;
472 int ret;
473
474 ret = kstrtobool(s: buf, res: &cdrom);
475 if (ret)
476 return ret;
477
478 down_read(sem: filesem);
479 ret = cdrom ? _fsg_store_ro(curlun, ro: true) : 0;
480
481 if (!ret) {
482 curlun->cdrom = cdrom;
483 ret = count;
484 }
485 up_read(sem: filesem);
486
487 return ret;
488}
489EXPORT_SYMBOL_GPL(fsg_store_cdrom);
490
491ssize_t fsg_store_removable(struct fsg_lun *curlun, const char *buf,
492 size_t count)
493{
494 bool removable;
495 int ret;
496
497 ret = kstrtobool(s: buf, res: &removable);
498 if (ret)
499 return ret;
500
501 curlun->removable = removable;
502
503 return count;
504}
505EXPORT_SYMBOL_GPL(fsg_store_removable);
506
507ssize_t fsg_store_inquiry_string(struct fsg_lun *curlun, const char *buf,
508 size_t count)
509{
510 const size_t len = min(count, sizeof(curlun->inquiry_string));
511
512 if (len == 0 || buf[0] == '\n') {
513 curlun->inquiry_string[0] = 0;
514 } else {
515 snprintf(buf: curlun->inquiry_string,
516 size: sizeof(curlun->inquiry_string), fmt: "%-28s", buf);
517 if (curlun->inquiry_string[len-1] == '\n')
518 curlun->inquiry_string[len-1] = ' ';
519 }
520
521 return count;
522}
523EXPORT_SYMBOL_GPL(fsg_store_inquiry_string);
524
525ssize_t fsg_store_forced_eject(struct fsg_lun *curlun, struct rw_semaphore *filesem,
526 const char *buf, size_t count)
527{
528 int ret;
529
530 /*
531 * Forcibly detach the backing file from the LUN
532 * regardless of whether the host has allowed it.
533 */
534 curlun->prevent_medium_removal = 0;
535 ret = fsg_store_file(curlun, filesem, "", 0);
536 return ret < 0 ? ret : count;
537}
538EXPORT_SYMBOL_GPL(fsg_store_forced_eject);
539
540MODULE_DESCRIPTION("Common definitions for mass storage functionality");
541MODULE_LICENSE("GPL");
542

source code of linux/drivers/usb/gadget/function/storage_common.c