1 /*
2  * storage_common.c -- Common definitions for mass storage functionality
3  *
4  * Copyright (C) 2003-2008 Alan Stern
5  * Copyeight (C) 2009 Samsung Electronics
6  * Author: Michal Nazarewicz (mina86@mina86.com)
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License as published by
10  * the Free Software Foundation; either version 2 of the License, or
11  * (at your option) any later version.
12  */
13 
14 /*
15  * This file requires the following identifiers used in USB strings to
16  * be defined (each of type pointer to char):
17  *  - fsg_string_interface    -- name of the interface
18  */
19 
20 /*
21  * When USB_GADGET_DEBUG_FILES is defined the module param num_buffers
22  * sets the number of pipeline buffers (length of the fsg_buffhd array).
23  * The valid range of num_buffers is: num >= 2 && num <= 4.
24  */
25 
26 #include <linux/module.h>
27 #include <linux/blkdev.h>
28 #include <linux/file.h>
29 #include <linux/fs.h>
30 #include <linux/usb/composite.h>
31 
32 #include "storage_common.h"
33 
34 /* There is only one interface. */
35 
36 struct usb_interface_descriptor fsg_intf_desc = {
37 	.bLength =		sizeof fsg_intf_desc,
38 	.bDescriptorType =	USB_DT_INTERFACE,
39 
40 	.bNumEndpoints =	2,		/* Adjusted during fsg_bind() */
41 	.bInterfaceClass =	USB_CLASS_MASS_STORAGE,
42 	.bInterfaceSubClass =	USB_SC_SCSI,	/* Adjusted during fsg_bind() */
43 	.bInterfaceProtocol =	USB_PR_BULK,	/* Adjusted during fsg_bind() */
44 	.iInterface =		FSG_STRING_INTERFACE,
45 };
46 EXPORT_SYMBOL_GPL(fsg_intf_desc);
47 
48 /*
49  * Three full-speed endpoint descriptors: bulk-in, bulk-out, and
50  * interrupt-in.
51  */
52 
53 struct usb_endpoint_descriptor fsg_fs_bulk_in_desc = {
54 	.bLength =		USB_DT_ENDPOINT_SIZE,
55 	.bDescriptorType =	USB_DT_ENDPOINT,
56 
57 	.bEndpointAddress =	USB_DIR_IN,
58 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
59 	/* wMaxPacketSize set by autoconfiguration */
60 };
61 EXPORT_SYMBOL_GPL(fsg_fs_bulk_in_desc);
62 
63 struct usb_endpoint_descriptor fsg_fs_bulk_out_desc = {
64 	.bLength =		USB_DT_ENDPOINT_SIZE,
65 	.bDescriptorType =	USB_DT_ENDPOINT,
66 
67 	.bEndpointAddress =	USB_DIR_OUT,
68 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
69 	/* wMaxPacketSize set by autoconfiguration */
70 };
71 EXPORT_SYMBOL_GPL(fsg_fs_bulk_out_desc);
72 
73 struct usb_descriptor_header *fsg_fs_function[] = {
74 	(struct usb_descriptor_header *) &fsg_intf_desc,
75 	(struct usb_descriptor_header *) &fsg_fs_bulk_in_desc,
76 	(struct usb_descriptor_header *) &fsg_fs_bulk_out_desc,
77 	NULL,
78 };
79 EXPORT_SYMBOL_GPL(fsg_fs_function);
80 
81 
82 /*
83  * USB 2.0 devices need to expose both high speed and full speed
84  * descriptors, unless they only run at full speed.
85  *
86  * That means alternate endpoint descriptors (bigger packets)
87  * and a "device qualifier" ... plus more construction options
88  * for the configuration descriptor.
89  */
90 struct usb_endpoint_descriptor fsg_hs_bulk_in_desc = {
91 	.bLength =		USB_DT_ENDPOINT_SIZE,
92 	.bDescriptorType =	USB_DT_ENDPOINT,
93 
94 	/* bEndpointAddress copied from fs_bulk_in_desc during fsg_bind() */
95 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
96 	.wMaxPacketSize =	cpu_to_le16(512),
97 };
98 EXPORT_SYMBOL_GPL(fsg_hs_bulk_in_desc);
99 
100 struct usb_endpoint_descriptor fsg_hs_bulk_out_desc = {
101 	.bLength =		USB_DT_ENDPOINT_SIZE,
102 	.bDescriptorType =	USB_DT_ENDPOINT,
103 
104 	/* bEndpointAddress copied from fs_bulk_out_desc during fsg_bind() */
105 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
106 	.wMaxPacketSize =	cpu_to_le16(512),
107 	.bInterval =		1,	/* NAK every 1 uframe */
108 };
109 EXPORT_SYMBOL_GPL(fsg_hs_bulk_out_desc);
110 
111 
112 struct usb_descriptor_header *fsg_hs_function[] = {
113 	(struct usb_descriptor_header *) &fsg_intf_desc,
114 	(struct usb_descriptor_header *) &fsg_hs_bulk_in_desc,
115 	(struct usb_descriptor_header *) &fsg_hs_bulk_out_desc,
116 	NULL,
117 };
118 EXPORT_SYMBOL_GPL(fsg_hs_function);
119 
120 struct usb_endpoint_descriptor fsg_ss_bulk_in_desc = {
121 	.bLength =		USB_DT_ENDPOINT_SIZE,
122 	.bDescriptorType =	USB_DT_ENDPOINT,
123 
124 	/* bEndpointAddress copied from fs_bulk_in_desc during fsg_bind() */
125 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
126 	.wMaxPacketSize =	cpu_to_le16(1024),
127 };
128 EXPORT_SYMBOL_GPL(fsg_ss_bulk_in_desc);
129 
130 struct usb_ss_ep_comp_descriptor fsg_ss_bulk_in_comp_desc = {
131 	.bLength =		sizeof(fsg_ss_bulk_in_comp_desc),
132 	.bDescriptorType =	USB_DT_SS_ENDPOINT_COMP,
133 
134 	/*.bMaxBurst =		DYNAMIC, */
135 };
136 EXPORT_SYMBOL_GPL(fsg_ss_bulk_in_comp_desc);
137 
138 struct usb_endpoint_descriptor fsg_ss_bulk_out_desc = {
139 	.bLength =		USB_DT_ENDPOINT_SIZE,
140 	.bDescriptorType =	USB_DT_ENDPOINT,
141 
142 	/* bEndpointAddress copied from fs_bulk_out_desc during fsg_bind() */
143 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
144 	.wMaxPacketSize =	cpu_to_le16(1024),
145 };
146 EXPORT_SYMBOL_GPL(fsg_ss_bulk_out_desc);
147 
148 struct usb_ss_ep_comp_descriptor fsg_ss_bulk_out_comp_desc = {
149 	.bLength =		sizeof(fsg_ss_bulk_in_comp_desc),
150 	.bDescriptorType =	USB_DT_SS_ENDPOINT_COMP,
151 
152 	/*.bMaxBurst =		DYNAMIC, */
153 };
154 EXPORT_SYMBOL_GPL(fsg_ss_bulk_out_comp_desc);
155 
156 struct usb_descriptor_header *fsg_ss_function[] = {
157 	(struct usb_descriptor_header *) &fsg_intf_desc,
158 	(struct usb_descriptor_header *) &fsg_ss_bulk_in_desc,
159 	(struct usb_descriptor_header *) &fsg_ss_bulk_in_comp_desc,
160 	(struct usb_descriptor_header *) &fsg_ss_bulk_out_desc,
161 	(struct usb_descriptor_header *) &fsg_ss_bulk_out_comp_desc,
162 	NULL,
163 };
164 EXPORT_SYMBOL_GPL(fsg_ss_function);
165 
166 
167  /*-------------------------------------------------------------------------*/
168 
169 /*
170  * If the next two routines are called while the gadget is registered,
171  * the caller must own fsg->filesem for writing.
172  */
173 
174 void fsg_lun_close(struct fsg_lun *curlun)
175 {
176 	if (curlun->filp) {
177 		LDBG(curlun, "close backing file\n");
178 		fput(curlun->filp);
179 		curlun->filp = NULL;
180 	}
181 }
182 EXPORT_SYMBOL_GPL(fsg_lun_close);
183 
184 int fsg_lun_open(struct fsg_lun *curlun, const char *filename)
185 {
186 	int				ro;
187 	struct file			*filp = NULL;
188 	int				rc = -EINVAL;
189 	struct inode			*inode = NULL;
190 	loff_t				size;
191 	loff_t				num_sectors;
192 	loff_t				min_sectors;
193 	unsigned int			blkbits;
194 	unsigned int			blksize;
195 
196 	/* R/W if we can, R/O if we must */
197 	ro = curlun->initially_ro;
198 	if (!ro) {
199 		filp = filp_open(filename, O_RDWR | O_LARGEFILE, 0);
200 		if (PTR_ERR(filp) == -EROFS || PTR_ERR(filp) == -EACCES)
201 			ro = 1;
202 	}
203 	if (ro)
204 		filp = filp_open(filename, O_RDONLY | O_LARGEFILE, 0);
205 	if (IS_ERR(filp)) {
206 		LINFO(curlun, "unable to open backing file: %s\n", filename);
207 		return PTR_ERR(filp);
208 	}
209 
210 	if (!(filp->f_mode & FMODE_WRITE))
211 		ro = 1;
212 
213 	inode = file_inode(filp);
214 	if ((!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode))) {
215 		LINFO(curlun, "invalid file type: %s\n", filename);
216 		goto out;
217 	}
218 
219 	/*
220 	 * If we can't read the file, it's no good.
221 	 * If we can't write the file, use it read-only.
222 	 */
223 	if (!(filp->f_mode & FMODE_CAN_READ)) {
224 		LINFO(curlun, "file not readable: %s\n", filename);
225 		goto out;
226 	}
227 	if (!(filp->f_mode & FMODE_CAN_WRITE))
228 		ro = 1;
229 
230 	size = i_size_read(inode->i_mapping->host);
231 	if (size < 0) {
232 		LINFO(curlun, "unable to find file size: %s\n", filename);
233 		rc = (int) size;
234 		goto out;
235 	}
236 
237 	if (curlun->cdrom) {
238 		blksize = 2048;
239 		blkbits = 11;
240 	} else if (inode->i_bdev) {
241 		blksize = bdev_logical_block_size(inode->i_bdev);
242 		blkbits = blksize_bits(blksize);
243 	} else {
244 		blksize = 512;
245 		blkbits = 9;
246 	}
247 
248 	num_sectors = size >> blkbits; /* File size in logic-block-size blocks */
249 	min_sectors = 1;
250 	if (curlun->cdrom) {
251 		min_sectors = 300;	/* Smallest track is 300 frames */
252 		if (num_sectors >= 256*60*75) {
253 			num_sectors = 256*60*75 - 1;
254 			LINFO(curlun, "file too big: %s\n", filename);
255 			LINFO(curlun, "using only first %d blocks\n",
256 					(int) num_sectors);
257 		}
258 	}
259 	if (num_sectors < min_sectors) {
260 		LINFO(curlun, "file too small: %s\n", filename);
261 		rc = -ETOOSMALL;
262 		goto out;
263 	}
264 
265 	if (fsg_lun_is_open(curlun))
266 		fsg_lun_close(curlun);
267 
268 	curlun->blksize = blksize;
269 	curlun->blkbits = blkbits;
270 	curlun->ro = ro;
271 	curlun->filp = filp;
272 	curlun->file_length = size;
273 	curlun->num_sectors = num_sectors;
274 	LDBG(curlun, "open backing file: %s\n", filename);
275 	return 0;
276 
277 out:
278 	fput(filp);
279 	return rc;
280 }
281 EXPORT_SYMBOL_GPL(fsg_lun_open);
282 
283 
284 /*-------------------------------------------------------------------------*/
285 
286 /*
287  * Sync the file data, don't bother with the metadata.
288  * This code was copied from fs/buffer.c:sys_fdatasync().
289  */
290 int fsg_lun_fsync_sub(struct fsg_lun *curlun)
291 {
292 	struct file	*filp = curlun->filp;
293 
294 	if (curlun->ro || !filp)
295 		return 0;
296 	return vfs_fsync(filp, 1);
297 }
298 EXPORT_SYMBOL_GPL(fsg_lun_fsync_sub);
299 
300 void store_cdrom_address(u8 *dest, int msf, u32 addr)
301 {
302 	if (msf) {
303 		/* Convert to Minutes-Seconds-Frames */
304 		addr >>= 2;		/* Convert to 2048-byte frames */
305 		addr += 2*75;		/* Lead-in occupies 2 seconds */
306 		dest[3] = addr % 75;	/* Frames */
307 		addr /= 75;
308 		dest[2] = addr % 60;	/* Seconds */
309 		addr /= 60;
310 		dest[1] = addr;		/* Minutes */
311 		dest[0] = 0;		/* Reserved */
312 	} else {
313 		/* Absolute sector */
314 		put_unaligned_be32(addr, dest);
315 	}
316 }
317 EXPORT_SYMBOL_GPL(store_cdrom_address);
318 
319 /*-------------------------------------------------------------------------*/
320 
321 
322 ssize_t fsg_show_ro(struct fsg_lun *curlun, char *buf)
323 {
324 	return sprintf(buf, "%d\n", fsg_lun_is_open(curlun)
325 				  ? curlun->ro
326 				  : curlun->initially_ro);
327 }
328 EXPORT_SYMBOL_GPL(fsg_show_ro);
329 
330 ssize_t fsg_show_nofua(struct fsg_lun *curlun, char *buf)
331 {
332 	return sprintf(buf, "%u\n", curlun->nofua);
333 }
334 EXPORT_SYMBOL_GPL(fsg_show_nofua);
335 
336 ssize_t fsg_show_file(struct fsg_lun *curlun, struct rw_semaphore *filesem,
337 		      char *buf)
338 {
339 	char		*p;
340 	ssize_t		rc;
341 
342 	down_read(filesem);
343 	if (fsg_lun_is_open(curlun)) {	/* Get the complete pathname */
344 		p = d_path(&curlun->filp->f_path, buf, PAGE_SIZE - 1);
345 		if (IS_ERR(p))
346 			rc = PTR_ERR(p);
347 		else {
348 			rc = strlen(p);
349 			memmove(buf, p, rc);
350 			buf[rc] = '\n';		/* Add a newline */
351 			buf[++rc] = 0;
352 		}
353 	} else {				/* No file, return 0 bytes */
354 		*buf = 0;
355 		rc = 0;
356 	}
357 	up_read(filesem);
358 	return rc;
359 }
360 EXPORT_SYMBOL_GPL(fsg_show_file);
361 
362 ssize_t fsg_show_cdrom(struct fsg_lun *curlun, char *buf)
363 {
364 	return sprintf(buf, "%u\n", curlun->cdrom);
365 }
366 EXPORT_SYMBOL_GPL(fsg_show_cdrom);
367 
368 ssize_t fsg_show_removable(struct fsg_lun *curlun, char *buf)
369 {
370 	return sprintf(buf, "%u\n", curlun->removable);
371 }
372 EXPORT_SYMBOL_GPL(fsg_show_removable);
373 
374 /*
375  * The caller must hold fsg->filesem for reading when calling this function.
376  */
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 
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 
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 
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 
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 
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 
504 MODULE_LICENSE("GPL");
505