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Commit c3d3c472 authored by Alan Stern's avatar Alan Stern Committed by Greg Kroah-Hartman
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[PATCH] USB: Code improvements for core/config.c 

This patch makes some improvements to the code in config.c.

	Create a subroutine to handle the repeated task of skipping
	forward to the next descriptor of a certain type.

	Remove some fairly useless debugging messages (they could
	never even have been enabled in the pre-as221 code).

	Verify that endpoint descriptors don't have an address
	equal to 0 (as well as not being above 15).

	Rename some local variables so they are a little more
	consistent and meaningful.

Despite all the changes, the functionality should remain the same.
Please apply.
parent e51bf644
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Inline Side-by-side
Showing with 102 additions and 135 deletions
drivers/usb/core/config.c
View file @ c3d3c472
......@@ -17,14 +17,38 @@
#define USB_MAXCONFIG 8 /* Arbitrary limit */
static int find_next_descriptor(unsigned char *buffer, int size,
int dt1, int dt2, int *num_skipped)
{
struct usb_descriptor_header *h;
int n = 0;
unsigned char *buffer0 = buffer;
/* Find the next descriptor of type dt1 or dt2 */
while (size >= sizeof(struct usb_descriptor_header)) {
h = (struct usb_descriptor_header *) buffer;
if (h->bDescriptorType == dt1 || h->bDescriptorType == dt2)
break;
buffer += h->bLength;
size -= h->bLength;
++n;
}
/* Store the number of descriptors skipped and return the
* number of bytes skipped */
if (num_skipped)
*num_skipped = n;
return buffer - buffer0;
}
static int usb_parse_endpoint(struct device *ddev, int cfgno, int inum,
int asnum, struct usb_host_endpoint *endpoint,
unsigned char *buffer, int size)
{
unsigned char *buffer0 = buffer;
struct usb_descriptor_header *header;
unsigned char *begin;
int numskipped;
int n, i;
header = (struct usb_descriptor_header *)buffer;
if (header->bDescriptorType != USB_DT_ENDPOINT) {
......@@ -47,7 +71,8 @@ static int usb_parse_endpoint(struct device *ddev, int cfgno, int inum,
return -EINVAL;
}
if ((endpoint->desc.bEndpointAddress & ~USB_ENDPOINT_DIR_MASK) >= 16) {
i = endpoint->desc.bEndpointAddress & ~USB_ENDPOINT_DIR_MASK;
if (i >= 16 || i == 0) {
dev_err(ddev, "config %d interface %d altsetting %d has an "
"invalid endpoint with address 0x%X\n",
cfgno, inum, asnum, endpoint->desc.bEndpointAddress);
......@@ -59,32 +84,16 @@ static int usb_parse_endpoint(struct device *ddev, int cfgno, int inum,
buffer += header->bLength;
size -= header->bLength;
/* Skip over any Class Specific or Vendor Specific descriptors */
begin = buffer;
numskipped = 0;
while (size >= sizeof(struct usb_descriptor_header)) {
header = (struct usb_descriptor_header *)buffer;
/* If we find another "proper" descriptor then we're done */
if ((header->bDescriptorType == USB_DT_ENDPOINT) ||
(header->bDescriptorType == USB_DT_INTERFACE))
break;
dev_dbg(ddev, "skipping descriptor 0x%X\n",
header->bDescriptorType);
numskipped++;
buffer += header->bLength;
size -= header->bLength;
}
if (numskipped) {
/* Skip over any Class Specific or Vendor Specific descriptors;
* find the next endpoint or interface descriptor */
endpoint->extra = buffer;
i = find_next_descriptor(buffer, size, USB_DT_ENDPOINT,
USB_DT_INTERFACE, &n);
endpoint->extralen = i;
if (n > 0)
dev_dbg(ddev, "skipped %d class/vendor specific endpoint "
"descriptors\n", numskipped);
endpoint->extra = begin;
endpoint->extralen = buffer - begin;
}
return buffer - buffer0;
"descriptors\n", n);
return buffer - buffer0 + i;
}
static void usb_free_intf(struct usb_interface *intf)
......@@ -93,9 +102,9 @@ static void usb_free_intf(struct usb_interface *intf)
if (intf->altsetting) {
for (j = 0; j < intf->num_altsetting; j++) {
struct usb_host_interface *as = &intf->altsetting[j];
struct usb_host_interface *alt = &intf->altsetting[j];
kfree(as->endpoint);
kfree(alt->endpoint);
}
kfree(intf->altsetting);
}
......@@ -109,13 +118,14 @@ static int usb_parse_interface(struct device *ddev, int cfgno,
struct usb_interface_descriptor *d;
int inum, asnum;
struct usb_interface *interface;
struct usb_host_interface *ifp;
int len, numskipped;
struct usb_descriptor_header *header;
unsigned char *begin;
int i, retval;
struct usb_host_interface *alt;
int i, n;
int len, retval;
d = (struct usb_interface_descriptor *) buffer;
buffer += d->bLength;
size -= d->bLength;
if (d->bDescriptorType != USB_DT_INTERFACE) {
dev_err(ddev, "config %d has an unexpected descriptor of type "
"0x%X, expecting interface type 0x%X\n",
......@@ -124,21 +134,8 @@ static int usb_parse_interface(struct device *ddev, int cfgno,
}
inum = d->bInterfaceNumber;
if (inum >= config->desc.bNumInterfaces) {
/* Skip to the next interface descriptor */
buffer += d->bLength;
size -= d->bLength;
while (size >= sizeof(struct usb_descriptor_header)) {
header = (struct usb_descriptor_header *) buffer;
if (header->bDescriptorType == USB_DT_INTERFACE)
break;
buffer += header->bLength;
size -= header->bLength;
}
return buffer - buffer0;
}
if (inum >= config->desc.bNumInterfaces)
goto skip_to_next_interface_descriptor;
interface = config->interface[inum];
asnum = d->bAlternateSetting;
......@@ -149,57 +146,41 @@ static int usb_parse_interface(struct device *ddev, int cfgno,
return -EINVAL;
}
ifp = &interface->altsetting[asnum];
if (ifp->desc.bLength) {
alt = &interface->altsetting[asnum];
if (alt->desc.bLength) {
dev_err(ddev, "Duplicate descriptor for config %d "
"interface %d altsetting %d\n", cfgno, inum, asnum);
return -EINVAL;
}
memcpy(&ifp->desc, buffer, USB_DT_INTERFACE_SIZE);
memcpy(&alt->desc, d, USB_DT_INTERFACE_SIZE);
buffer += d->bLength;
size -= d->bLength;
/* Skip over any Class Specific or Vendor Specific descriptors */
begin = buffer;
numskipped = 0;
while (size >= sizeof(struct usb_descriptor_header)) {
header = (struct usb_descriptor_header *)buffer;
/* If we find another "proper" descriptor then we're done */
if ((header->bDescriptorType == USB_DT_INTERFACE) ||
(header->bDescriptorType == USB_DT_ENDPOINT))
break;
dev_dbg(ddev, "skipping descriptor 0x%X\n",
header->bDescriptorType);
numskipped++;
buffer += header->bLength;
size -= header->bLength;
}
if (numskipped) {
/* Skip over any Class Specific or Vendor Specific descriptors;
* find the first endpoint or interface descriptor */
alt->extra = buffer;
i = find_next_descriptor(buffer, size, USB_DT_ENDPOINT,
USB_DT_INTERFACE, &n);
alt->extralen = i;
if (n > 0)
dev_dbg(ddev, "skipped %d class/vendor specific "
"interface descriptors\n", numskipped);
ifp->extra = begin;
ifp->extralen = buffer - begin;
}
"interface descriptors\n", n);
buffer += i;
size -= i;
if (ifp->desc.bNumEndpoints > USB_MAXENDPOINTS) {
if (alt->desc.bNumEndpoints > USB_MAXENDPOINTS) {
dev_err(ddev, "too many endpoints for config %d interface %d "
"altsetting %d: %d, maximum allowed: %d\n",
cfgno, inum, asnum, ifp->desc.bNumEndpoints,
cfgno, inum, asnum, alt->desc.bNumEndpoints,
USB_MAXENDPOINTS);
return -EINVAL;
}
len = ifp->desc.bNumEndpoints * sizeof(struct usb_host_endpoint);
ifp->endpoint = kmalloc(len, GFP_KERNEL);
if (!ifp->endpoint)
len = alt->desc.bNumEndpoints * sizeof(struct usb_host_endpoint);
alt->endpoint = kmalloc(len, GFP_KERNEL);
if (!alt->endpoint)
return -ENOMEM;
memset(ifp->endpoint, 0, len);
memset(alt->endpoint, 0, len);
for (i = 0; i < ifp->desc.bNumEndpoints; i++) {
for (i = 0; i < alt->desc.bNumEndpoints; i++) {
if (size < USB_DT_ENDPOINT_SIZE) {
dev_err(ddev, "too few endpoint descriptors for "
"config %d interface %d altsetting %d\n",
......@@ -208,15 +189,19 @@ static int usb_parse_interface(struct device *ddev, int cfgno,
}
retval = usb_parse_endpoint(ddev, cfgno, inum, asnum,
ifp->endpoint + i, buffer, size);
alt->endpoint + i, buffer, size);
if (retval < 0)
return retval;
buffer += retval;
size -= retval;
}
return buffer - buffer0;
skip_to_next_interface_descriptor:
i = find_next_descriptor(buffer, size, USB_DT_INTERFACE,
USB_DT_INTERFACE, NULL);
return buffer - buffer0 + i;
}
int usb_parse_configuration(struct device *ddev, int cfgidx,
......@@ -224,14 +209,12 @@ int usb_parse_configuration(struct device *ddev, int cfgidx,
{
int cfgno;
int nintf, nintf_orig;
int i, j;
int i, j, n;
struct usb_interface *interface;
unsigned char *buffer2;
int size2;
struct usb_descriptor_header *header;
int numskipped, len;
unsigned char *begin;
int retval;
int len, retval;
memcpy(&config->desc, buffer, USB_DT_CONFIG_SIZE);
if (config->desc.bDescriptorType != USB_DT_CONFIG ||
......@@ -244,6 +227,9 @@ int usb_parse_configuration(struct device *ddev, int cfgidx,
config->desc.wTotalLength = size;
cfgno = config->desc.bConfigurationValue;
buffer += config->desc.bLength;
size -= config->desc.bLength;
nintf = nintf_orig = config->desc.bNumInterfaces;
if (nintf > USB_MAXINTERFACES) {
dev_warn(ddev, "config %d has too many interfaces: %d, "
......@@ -255,7 +241,6 @@ int usb_parse_configuration(struct device *ddev, int cfgidx,
for (i = 0; i < nintf; ++i) {
interface = config->interface[i] =
kmalloc(sizeof(struct usb_interface), GFP_KERNEL);
dev_dbg(ddev, "kmalloc IF %p, numif %i\n", interface, i);
if (!interface)
return -ENOMEM;
memset(interface, 0, sizeof(struct usb_interface));
......@@ -263,10 +248,10 @@ int usb_parse_configuration(struct device *ddev, int cfgidx,
/* Go through the descriptors, checking their length and counting the
* number of altsettings for each interface */
buffer2 = buffer;
size2 = size;
j = 0;
while (size2 >= sizeof(struct usb_descriptor_header)) {
for ((buffer2 = buffer, size2 = size);
size2 >= sizeof(struct usb_descriptor_header);
(buffer2 += header->bLength, size2 -= header->bLength)) {
header = (struct usb_descriptor_header *) buffer2;
if ((header->bLength > size2) || (header->bLength < 2)) {
dev_err(ddev, "config %d has an invalid descriptor "
......@@ -277,13 +262,14 @@ int usb_parse_configuration(struct device *ddev, int cfgidx,
if (header->bDescriptorType == USB_DT_INTERFACE) {
struct usb_interface_descriptor *d;
if (header->bLength < USB_DT_INTERFACE_SIZE) {
d = (struct usb_interface_descriptor *) header;
if (d->bLength < USB_DT_INTERFACE_SIZE) {
dev_err(ddev, "config %d has an invalid "
"interface descriptor of length %d\n",
cfgno, header->bLength);
cfgno, d->bLength);
return -EINVAL;
}
d = (struct usb_interface_descriptor *) header;
i = d->bInterfaceNumber;
if (i >= nintf_orig) {
dev_err(ddev, "config %d has an invalid "
......@@ -294,21 +280,18 @@ int usb_parse_configuration(struct device *ddev, int cfgidx,
if (i < nintf)
++config->interface[i]->num_altsetting;
} else if ((header->bDescriptorType == USB_DT_DEVICE ||
header->bDescriptorType == USB_DT_CONFIG) && j) {
} else if (header->bDescriptorType == USB_DT_DEVICE ||
header->bDescriptorType == USB_DT_CONFIG) {
dev_err(ddev, "config %d contains an unexpected "
"descriptor of type 0x%X\n",
cfgno, header->bDescriptorType);
return -EINVAL;
}
j = 1;
buffer2 += header->bLength;
size2 -= header->bLength;
}
} /* for ((buffer2 = buffer, size2 = size); ...) */
/* Allocate the altsetting arrays */
for (i = 0; i < config->desc.bNumInterfaces; ++i) {
for (i = 0; i < nintf; ++i) {
interface = config->interface[i];
if (interface->num_altsetting > USB_MAXALTSETTING) {
dev_err(ddev, "too many alternate settings for "
......@@ -332,33 +315,17 @@ int usb_parse_configuration(struct device *ddev, int cfgidx,
memset(interface->altsetting, 0, len);
}
buffer += config->desc.bLength;
size -= config->desc.bLength;
/* Skip over any Class Specific or Vendor Specific descriptors */
begin = buffer;
numskipped = 0;
while (size >= sizeof(struct usb_descriptor_header)) {
header = (struct usb_descriptor_header *)buffer;
/* If we find another "proper" descriptor then we're done */
if ((header->bDescriptorType == USB_DT_ENDPOINT) ||
(header->bDescriptorType == USB_DT_INTERFACE))
break;
dev_dbg(ddev, "skipping descriptor 0x%X\n",
header->bDescriptorType);
numskipped++;
buffer += header->bLength;
size -= header->bLength;
}
if (numskipped) {
dev_dbg(ddev, "skipped %d class/vendor specific configuration "
"descriptors\n", numskipped);
config->extra = begin;
config->extralen = buffer - begin;
}
/* Skip over any Class Specific or Vendor Specific descriptors;
* find the first interface descriptor */
config->extra = buffer;
i = find_next_descriptor(buffer, size, USB_DT_INTERFACE,
USB_DT_INTERFACE, &n);
config->extralen = i;
if (n > 0)
dev_dbg(ddev, "skipped %d class/vendor specific "
"configuration descriptors\n", n);
buffer += i;
size -= i;
/* Parse all the interface/altsetting descriptors */
while (size >= sizeof(struct usb_descriptor_header)) {
......
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