// SPDX-License-Identifier: GPL-2.0+
/*
* storage_common.c -- Common definitions for mass storage functionality
*
* Copyright (C) 2003-2008 Alan Stern
* Copyeight (C) 2009 Samsung Electronics
* Author: Michal Nazarewicz ([email protected])
*/
/*
* This file requires the following identifiers used in USB strings to
* be defined (each of type pointer to char):
* - fsg_string_interface -- name of the interface
*/
/*
* When USB_GADGET_DEBUG_FILES is defined the module param num_buffers
* sets the number of pipeline buffers (length of the fsg_buffhd array).
* The valid range of num_buffers is: num >= 2 && num <= 4.
*/
#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/kstrtox.h>
#include <linux/usb/composite.h>
#include "storage_common.h"
/* There is only one interface. */
struct usb_interface_descriptor fsg_intf_desc = {
.bLength = sizeof fsg_intf_desc,
.bDescriptorType = USB_DT_INTERFACE,
.bNumEndpoints = 2, /* Adjusted during fsg_bind() */
.bInterfaceClass = USB_CLASS_MASS_STORAGE,
.bInterfaceSubClass = USB_SC_SCSI, /* Adjusted during fsg_bind() */
.bInterfaceProtocol = USB_PR_BULK, /* Adjusted during fsg_bind() */
.iInterface = FSG_STRING_INTERFACE,
};
EXPORT_SYMBOL_GPL(fsg_intf_desc);
/*
* Three full-speed endpoint descriptors: bulk-in, bulk-out, and
* interrupt-in.
*/
struct usb_endpoint_descriptor fsg_fs_bulk_in_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bEndpointAddress = USB_DIR_IN,
.bmAttributes = USB_ENDPOINT_XFER_BULK,
/* wMaxPacketSize set by autoconfiguration */
};
EXPORT_SYMBOL_GPL(fsg_fs_bulk_in_desc);
struct usb_endpoint_descriptor fsg_fs_bulk_out_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bEndpointAddress = USB_DIR_OUT,
.bmAttributes = USB_ENDPOINT_XFER_BULK,
/* wMaxPacketSize set by autoconfiguration */
};
EXPORT_SYMBOL_GPL(fsg_fs_bulk_out_desc);
struct usb_descriptor_header *fsg_fs_function[] = {
(struct usb_descriptor_header *) &fsg_intf_desc,
(struct usb_descriptor_header *) &fsg_fs_bulk_in_desc,
(struct usb_descriptor_header *) &fsg_fs_bulk_out_desc,
NULL,
};
EXPORT_SYMBOL_GPL(fsg_fs_function);
/*
* USB 2.0 devices need to expose both high speed and full speed
* descriptors, unless they only run at full speed.
*
* That means alternate endpoint descriptors (bigger packets).
*/
struct usb_endpoint_descriptor fsg_hs_bulk_in_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
/* bEndpointAddress copied from fs_bulk_in_desc during fsg_bind() */
.bmAttributes = USB_ENDPOINT_XFER_BULK,
.wMaxPacketSize = cpu_to_le16(512),
};
EXPORT_SYMBOL_GPL(fsg_hs_bulk_in_desc);
struct usb_endpoint_descriptor fsg_hs_bulk_out_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
/* bEndpointAddress copied from fs_bulk_out_desc during fsg_bind() */
.bmAttributes = USB_ENDPOINT_XFER_BULK,
.wMaxPacketSize = cpu_to_le16(512),
.bInterval = 1, /* NAK every 1 uframe */
};
EXPORT_SYMBOL_GPL(fsg_hs_bulk_out_desc);
struct usb_descriptor_header *fsg_hs_function[] = {
(struct usb_descriptor_header *) &fsg_intf_desc,
(struct usb_descriptor_header *) &fsg_hs_bulk_in_desc,
(struct usb_descriptor_header *) &fsg_hs_bulk_out_desc,
NULL,
};
EXPORT_SYMBOL_GPL(fsg_hs_function);
struct usb_endpoint_descriptor fsg_ss_bulk_in_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
/* bEndpointAddress copied from fs_bulk_in_desc during fsg_bind() */
.bmAttributes = USB_ENDPOINT_XFER_BULK,
.wMaxPacketSize = cpu_to_le16(1024),
};
EXPORT_SYMBOL_GPL(fsg_ss_bulk_in_desc);
struct usb_ss_ep_comp_descriptor fsg_ss_bulk_in_comp_desc = {
.bLength = sizeof(fsg_ss_bulk_in_comp_desc),
.bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
/*.bMaxBurst = DYNAMIC, */
};
EXPORT_SYMBOL_GPL(fsg_ss_bulk_in_comp_desc);
struct usb_endpoint_descriptor fsg_ss_bulk_out_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
/* bEndpointAddress copied from fs_bulk_out_desc during fsg_bind() */
.bmAttributes = USB_ENDPOINT_XFER_BULK,
.wMaxPacketSize = cpu_to_le16(1024),
};
EXPORT_SYMBOL_GPL(fsg_ss_bulk_out_desc);
struct usb_ss_ep_comp_descriptor fsg_ss_bulk_out_comp_desc = {
.bLength = sizeof(fsg_ss_bulk_in_comp_desc),
.bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
/*.bMaxBurst = DYNAMIC, */
};
EXPORT_SYMBOL_GPL(fsg_ss_bulk_out_comp_desc);
struct usb_descriptor_header *fsg_ss_function[] = {
(struct usb_descriptor_header *) &fsg_intf_desc,
(struct usb_descriptor_header *) &fsg_ss_bulk_in_desc,
(struct usb_descriptor_header *) &fsg_ss_bulk_in_comp_desc,
(struct usb_descriptor_header *) &fsg_ss_bulk_out_desc,
(struct usb_descriptor_header *) &fsg_ss_bulk_out_comp_desc,
NULL,
};
EXPORT_SYMBOL_GPL(fsg_ss_function);
/*-------------------------------------------------------------------------*/
/*
* If the next two routines are called while the gadget is registered,
* the caller must own fsg->filesem for writing.
*/
void fsg_lun_close(struct fsg_lun *curlun)
{
if (curlun->filp) {
LDBG(curlun, "close backing file\n");
fput(curlun->filp);
curlun->filp = NULL;
}
}
EXPORT_SYMBOL_GPL(fsg_lun_close);
int fsg_lun_open(struct fsg_lun *curlun, const char *filename)
{
int ro;
struct file *filp = NULL;
int rc = -EINVAL;
struct inode *inode = NULL;
loff_t size;
loff_t num_sectors;
loff_t min_sectors;
unsigned int blkbits;
unsigned int blksize;
/* R/W if we can, R/O if we must */
ro = curlun->initially_ro;
if (!ro) {
filp = filp_open(filename, O_RDWR | O_LARGEFILE, 0);
if (PTR_ERR(filp) == -EROFS || PTR_ERR(filp) == -EACCES)
ro = 1;
}
if (ro)
filp = filp_open(filename, O_RDONLY | O_LARGEFILE, 0);
if (IS_ERR(filp)) {
LINFO(curlun, "unable to open backing file: %s\n", filename);
return PTR_ERR(filp);
}
if (!(filp->f_mode & FMODE_WRITE))
ro = 1;
inode = filp->f_mapping->host;
if ((!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode))) {
LINFO(curlun, "invalid file type: %s\n", filename);
goto out;
}
/*
* If we can't read the file, it's no good.
* If we can't write the file, use it read-only.
*/
if (!(filp->f_mode & FMODE_CAN_READ)) {
LINFO(curlun, "file not readable: %s\n", filename);
goto out;
}
if (!(filp->f_mode & FMODE_CAN_WRITE))
ro = 1;
size = i_size_read(inode);
if (size < 0) {
LINFO(curlun, "unable to find file size: %s\n", filename);
rc = (int) size;
goto out;
}
if (curlun->cdrom) {
blksize = 2048;
blkbits = 11;
} else if (S_ISBLK(inode->i_mode)) {
blksize = bdev_logical_block_size(I_BDEV(inode));
blkbits = blksize_bits(blksize);
} else {
blksize = 512;
blkbits = 9;
}
num_sectors = size >> blkbits; /* File size in logic-block-size blocks */
min_sectors = 1;
if (curlun->cdrom) {
min_sectors = 300; /* Smallest track is 300 frames */
if (num_sectors >= 256*60*75) {
num_sectors = 256*60*75 - 1;
LINFO(curlun, "file too big: %s\n", filename);
LINFO(curlun, "using only first %d blocks\n",
(int) num_sectors);
}
}
if (num_sectors < min_sectors) {
LINFO(curlun, "file too small: %s\n", filename);
rc = -ETOOSMALL;
goto out;
}
if (fsg_lun_is_open(curlun))
fsg_lun_close(curlun);
curlun->blksize = blksize;
curlun->blkbits = blkbits;
curlun->ro = ro;
curlun->filp = filp;
curlun->file_length = size;
curlun->num_sectors = num_sectors;
LDBG(curlun, "open backing file: %s\n", filename);
return 0;
out:
fput(filp);
return rc;
}
EXPORT_SYMBOL_GPL(fsg_lun_open);
/*-------------------------------------------------------------------------*/
/*
* Sync the file data, don't bother with the metadata.
* This code was copied from fs/buffer.c:sys_fdatasync().
*/
int fsg_lun_fsync_sub(struct fsg_lun *curlun)
{
struct file *filp = curlun->filp;
if (curlun->ro || !filp)
return 0;
return vfs_fsync(filp, 1);
}
EXPORT_SYMBOL_GPL(fsg_lun_fsync_sub);
void store_cdrom_address(u8 *dest, int msf, u32 addr)
{
if (msf) {
/*
* Convert to Minutes-Seconds-Frames.
* Sector size is already set to 2048 bytes.
*/
addr += 2*75; /* Lead-in occupies 2 seconds */
dest[3] = addr % 75; /* Frames */
addr /= 75;
dest[2] = addr % 60; /* Seconds */
addr /= 60;
dest[1] = addr; /* Minutes */
dest[0] = 0; /* Reserved */
} else {
/* Absolute sector */
put_unaligned_be32(addr, dest);
}
}
EXPORT_SYMBOL_GPL(store_cdrom_address);
/*-------------------------------------------------------------------------*/
ssize_t fsg_show_ro(struct fsg_lun *curlun, char *buf)
{
return sprintf(buf, "%d\n", fsg_lun_is_open(curlun)
? curlun->ro
: curlun->initially_ro);
}
EXPORT_SYMBOL_GPL(fsg_show_ro);
ssize_t fsg_show_nofua(struct fsg_lun *curlun, char *buf)
{
return sprintf(buf, "%u\n", curlun->nofua);
}
EXPORT_SYMBOL_GPL(fsg_show_nofua);
ssize_t fsg_show_file(struct fsg_lun *curlun, struct rw_semaphore *filesem,
char *buf)
{
char *p;
ssize_t rc;
down_read(filesem);
if (fsg_lun_is_open(curlun)) { /* Get the complete pathname */
p = file_path(curlun->filp, buf, PAGE_SIZE - 1);
if (IS_ERR(p))
rc = PTR_ERR(p);
else {
rc = strlen(p);
memmove(buf, p, rc);
buf[rc] = '\n'; /* Add a newline */
buf[++rc] = 0;
}
} else { /* No file, return 0 bytes */
*buf = 0;
rc = 0;
}
up_read(filesem);
return rc;
}
EXPORT_SYMBOL_GPL(fsg_show_file);
ssize_t fsg_show_cdrom(struct fsg_lun *curlun, char *buf)
{
return sprintf(buf, "%u\n", curlun->cdrom);
}
EXPORT_SYMBOL_GPL(fsg_show_cdrom);
ssize_t fsg_show_removable(struct fsg_lun *curlun, char *buf)
{
return sprintf(buf, "%u\n", curlun->removable);
}
EXPORT_SYMBOL_GPL(fsg_show_removable);
ssize_t fsg_show_inquiry_string(struct fsg_lun *curlun, char *buf)
{
return sprintf(buf, "%s\n", curlun->inquiry_string);
}
EXPORT_SYMBOL_GPL(fsg_show_inquiry_string);
/*
* The caller must hold fsg->filesem for reading when calling this function.
*/
static ssize_t _fsg_store_ro(struct fsg_lun *curlun, bool ro)
{
if (fsg_lun_is_open(curlun)) {
LDBG(curlun, "read-only status change prevented\n");
return -EBUSY;
}
curlun->ro = ro;
curlun->initially_ro = ro;
LDBG(curlun, "read-only status set to %d\n", curlun->ro);
return 0;
}
ssize_t fsg_store_ro(struct fsg_lun *curlun, struct rw_semaphore *filesem,
const char *buf, size_t count)
{
ssize_t rc;
bool ro;
rc = kstrtobool(buf, &ro);
if (rc)
return rc;
/*
* Allow the write-enable status to change only while the
* backing file is closed.
*/
down_read(filesem);
rc = _fsg_store_ro(curlun, ro);
if (!rc)
rc = count;
up_read(filesem);
return rc;
}
EXPORT_SYMBOL_GPL(fsg_store_ro);
ssize_t fsg_store_nofua(struct fsg_lun *curlun, const char *buf, size_t count)
{
bool nofua;
int ret;
ret = kstrtobool(buf, &nofua);
if (ret)
return ret;
/* Sync data when switching from async mode to sync */
if (!nofua && curlun->nofua)
fsg_lun_fsync_sub(curlun);
curlun->nofua = nofua;
return count;
}
EXPORT_SYMBOL_GPL(fsg_store_nofua);
ssize_t fsg_store_file(struct fsg_lun *curlun, struct rw_semaphore *filesem,
const char *buf, size_t count)
{
int rc = 0;
if (curlun->prevent_medium_removal && fsg_lun_is_open(curlun)) {
LDBG(curlun, "eject attempt prevented\n");
return -EBUSY; /* "Door is locked" */
}
/* Remove a trailing newline */
if (count > 0 && buf[count-1] == '\n')
((char *) buf)[count-1] = 0; /* Ugh! */
/* Load new medium */
down_write(filesem);
if (count > 0 && buf[0]) {
/* fsg_lun_open() will close existing file if any. */
rc = fsg_lun_open(curlun, buf);
if (rc == 0)
curlun->unit_attention_data =
SS_NOT_READY_TO_READY_TRANSITION;
} else if (fsg_lun_is_open(curlun)) {
fsg_lun_close(curlun);
curlun->unit_attention_data = SS_MEDIUM_NOT_PRESENT;
}
up_write(filesem);
return (rc < 0 ? rc : count);
}
EXPORT_SYMBOL_GPL(fsg_store_file);
ssize_t fsg_store_cdrom(struct fsg_lun *curlun, struct rw_semaphore *filesem,
const char *buf, size_t count)
{
bool cdrom;
int ret;
ret = kstrtobool(buf, &cdrom);
if (ret)
return ret;
down_read(filesem);
ret = cdrom ? _fsg_store_ro(curlun, true) : 0;
if (!ret) {
curlun->cdrom = cdrom;
ret = count;
}
up_read(filesem);
return ret;
}
EXPORT_SYMBOL_GPL(fsg_store_cdrom);
ssize_t fsg_store_removable(struct fsg_lun *curlun, const char *buf,
size_t count)
{
bool removable;
int ret;
ret = kstrtobool(buf, &removable);
if (ret)
return ret;
curlun->removable = removable;
return count;
}
EXPORT_SYMBOL_GPL(fsg_store_removable);
ssize_t fsg_store_inquiry_string(struct fsg_lun *curlun, const char *buf,
size_t count)
{
const size_t len = min(count, sizeof(curlun->inquiry_string));
if (len == 0 || buf[0] == '\n') {
curlun->inquiry_string[0] = 0;
} else {
snprintf(curlun->inquiry_string,
sizeof(curlun->inquiry_string), "%-28s", buf);
if (curlun->inquiry_string[len-1] == '\n')
curlun->inquiry_string[len-1] = ' ';
}
return count;
}
EXPORT_SYMBOL_GPL(fsg_store_inquiry_string);
ssize_t fsg_store_forced_eject(struct fsg_lun *curlun, struct rw_semaphore *filesem,
const char *buf, size_t count)
{
int ret;
/*
* Forcibly detach the backing file from the LUN
* regardless of whether the host has allowed it.
*/
curlun->prevent_medium_removal = 0;
ret = fsg_store_file(curlun, filesem, "", 0);
return ret < 0 ? ret : count;
}
EXPORT_SYMBOL_GPL(fsg_store_forced_eject);
MODULE_DESCRIPTION("Common definitions for mass storage functionality");
MODULE_LICENSE("GPL");
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