MFC r322322: Expose device caps as libusb_bos_descriptor::dev_capability

Some libusb consumers in Linux-land (in this case, libusb4java) expect a
dev_capability member that they can use to enumerate the device
capabilities.

No particular layout is expected of this, just that it can be traversed
using the bLength member until bNumDeviceCapabilities are read and that the
consumer may then use one of the libusb_get_*_descriptor methods to extract
specific (usb 2.0 vs. ss) capability information.

2 files changed, 27 insertions, 2 deletions

diff --git a/lib/libusb/libusb.h b/lib/libusb/libusb.h
index 44bdb4b..42f55ab 100644
--- a/lib/libusb/libusb.h
+++ b/lib/libusb/libusb.h
@@ -388,6 +388,7 @@ typedef struct libusb_bos_descriptor {
 	uint8_t bNumDeviceCapabilities;
 	struct libusb_usb_2_0_device_capability_descriptor *usb_2_0_ext_cap;
 	struct libusb_ss_usb_device_capability_descriptor *ss_usb_cap;
+	struct libusb_bos_dev_capability_descriptor **dev_capability;
 }	libusb_bos_descriptor __aligned(sizeof(void *));
 
 typedef struct libusb_usb_2_0_extension_descriptor {
diff --git a/lib/libusb/libusb10_desc.c b/lib/libusb/libusb10_desc.c
index c214195..bbc3429 100644
--- a/lib/libusb/libusb10_desc.c
+++ b/lib/libusb/libusb10_desc.c
@@ -433,6 +433,7 @@ libusb_parse_bos_descriptor(const void *buf, int len,
 	struct libusb_bos_descriptor *ptr;
 	struct libusb_usb_2_0_device_capability_descriptor *dcap_20 = NULL;
 	struct libusb_ss_usb_device_capability_descriptor *ss_cap = NULL;
+	uint8_t index = 0;
 
 	if (buf == NULL || bos == NULL || len < 1)
 		return (LIBUSB_ERROR_INVALID_PARAM);
@@ -453,7 +454,8 @@ libusb_parse_bos_descriptor(const void *buf, int len,
 			break;
 
 		if (dlen >= LIBUSB_DT_BOS_SIZE &&
-		    dtype == LIBUSB_DT_BOS) {
+		    dtype == LIBUSB_DT_BOS &&
+		    ptr == NULL) {
 
 			ptr = malloc(sizeof(*ptr) + sizeof(*dcap_20) +
 			    sizeof(*ss_cap));
@@ -470,6 +472,11 @@ libusb_parse_bos_descriptor(const void *buf, int len,
 			ptr->bNumDeviceCapabilities = ((const uint8_t *)buf)[4];
 			ptr->usb_2_0_ext_cap = NULL;
 			ptr->ss_usb_cap = NULL;
+			ptr->dev_capability = calloc(ptr->bNumDeviceCapabilities, sizeof(void *));
+			if (ptr->dev_capability == NULL) {
+				free(ptr);
+				return (LIBUSB_ERROR_NO_MEM);
+			}
 
 			dcap_20 = (void *)(ptr + 1);
 			ss_cap = (void *)(dcap_20 + 1);
@@ -477,6 +484,15 @@ libusb_parse_bos_descriptor(const void *buf, int len,
 		if (dlen >= 3 &&
 		    ptr != NULL &&
 		    dtype == LIBUSB_DT_DEVICE_CAPABILITY) {
+			if (index != ptr->bNumDeviceCapabilities) {
+				ptr->dev_capability[index] = malloc(dlen);
+				if (ptr->dev_capability[index] == NULL) {
+					libusb_free_bos_descriptor(ptr);
+					return LIBUSB_ERROR_NO_MEM;
+				}
+				memcpy(ptr->dev_capability[index], buf, dlen);
+				index++;
+			}
 			switch (((const uint8_t *)buf)[2]) {
 			case LIBUSB_USB_2_0_EXTENSION_DEVICE_CAPABILITY:
 				if (ptr->usb_2_0_ext_cap != NULL || dcap_20 == NULL)
@@ -523,8 +539,11 @@ libusb_parse_bos_descriptor(const void *buf, int len,
 		buf = ((const uint8_t *)buf) + dlen;
 		len -= dlen;
 	}
-	if (ptr != NULL)
+
+	if (ptr != NULL) {
+		ptr->bNumDeviceCapabilities = index;
 		return (0);		/* success */
+	}
 
 	return (LIBUSB_ERROR_IO);
 }
@@ -532,9 +551,14 @@ libusb_parse_bos_descriptor(const void *buf, int len,
 void
 libusb_free_bos_descriptor(struct libusb_bos_descriptor *bos)
 {
+	uint8_t i;
+
 	if (bos == NULL)
 		return;
 
+	for (i = 0; i != bos->bNumDeviceCapabilities; i++)
+		free(bos->dev_capability[i]);
+	free(bos->dev_capability);
 	free(bos);
 }