From: Peter Henn <Peter.Henn@web.de>
Date: Tue, 1 Aug 2017 08:59:46 +0000 (+0000)
Subject: Bugfix access rights to USB devices
X-Git-Tag: v0.1~6
X-Git-Url: http://git.linex4red.de/pub/pl2303-ft232-gpio.git/commitdiff_plain/339fc97efde0b67de29c0c5a95f86393268d75d2

Bugfix access rights to USB devices

- cleanup USB search device code
- prevent opening any USB device, which has not matching VID/PID
- use context pointer instead of NULL
---

diff --git a/usb.c b/usb.c
index 905df10..ad9a09c 100644
--- a/usb.c
+++ b/usb.c
@@ -1,4 +1,3 @@
-
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
@@ -34,27 +33,23 @@ struct libusb_device_handle *ncusb_find_and_open(struct libusb_context *ctx,
 	}
 
 	for(i = 0; i < cnt; i++) {
-		int err = 0;
 		libusb_device *device = list[i];
 		struct libusb_device_descriptor desc;
 		libusb_device_handle *handle;
-		err = libusb_open(device, &handle);
-		if (err)
-			continue;
 
-		int r = libusb_get_device_descriptor( device, &desc );
-		if (r) {
-			libusb_close(handle);
+		if ( libusb_get_device_descriptor( device, &desc ) )
 			continue;
-		}
 
-		if ( desc.idVendor == vendor && desc.idProduct == product &&
-		     ncusb_match_string(handle, desc.iManufacturer, vendor_name) &&
-		     ncusb_match_string(handle, desc.iProduct,      product_name) &&
-		     ncusb_match_string(handle, desc.iSerialNumber, serial)
-			)
-		{
-			found = handle;
+		if ( desc.idVendor == vendor && desc.idProduct == product ) {
+			if ( libusb_open(device, &handle) )
+				continue;
+
+			if (ncusb_match_string(handle, desc.iManufacturer, vendor_name) &&
+			    ncusb_match_string(handle, desc.iProduct,     product_name) &&
+			    ncusb_match_string(handle, desc.iSerialNumber, serial) )
+			{
+				found = handle;
+			}
 		}
 
 		if (found)
@@ -69,13 +64,16 @@ struct libusb_device_handle *ncusb_find_and_open(struct libusb_context *ctx,
 
 void check_handle(libusb_device_handle **h, int vid, int pid, const char* manuf, const char* product, const char* serial)
 {
+	static libusb_context *ctx=NULL;
+
 	if (*h)
 		return;
-	libusb_init(NULL);
-	libusb_set_debug(NULL, LIBUSB_LOG_LEVEL_WARNING);
-	*h = ncusb_find_and_open(NULL, vid, pid, manuf, product, serial);
+	if (!ctx)
+		libusb_init(&ctx);
+	libusb_set_debug(ctx, LIBUSB_LOG_LEVEL_WARNING);
+	*h = ncusb_find_and_open(ctx, vid, pid, manuf, product, serial);
 	if (!(*h)) {
-		fprintf(stderr, "No PL2303 USB device %04x:%04x found ;(\n", vid, pid);
+		fprintf(stderr, "No USB device %04x:%04x found ;(\n", vid, pid);
 		exit(1);
 	}
 }