libusb_helper: fix memory leak when no adapter is found

When jtag_libusb_open() fails to find the adapter, it returns
error but left libusb initialized causing memory leak of libusb
internal data.
Issue found with valgrind when no adapter or board is connected to
the host, e.g.
	valgrind openocd -f board/st_nucleo_f4.cfg

Close the libusb operations if jtag_libusb_open() has to return
error.

Change-Id: Ieb2f110be15705dafe80c099e7d83c07056c2a41
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: http://openocd.zylin.com/5701
Tested-by: jenkins

diff --git a/src/jtag/drivers/libusb_helper.c b/src/jtag/drivers/libusb_helper.c
index fbbfb4114bc07635d6203773012f2a78b2de6535..184882abcc726706ffe473244795c19d81ad9421 100644 (file)
--- a/src/jtag/drivers/libusb_helper.c
+++ b/src/jtag/drivers/libusb_helper.c
@@ -208,6 +208,9 @@ int jtag_libusb_open(const uint16_t vids[], const uint16_t pids[],
        if (serial_mismatch)
                LOG_INFO("No device matches the serial string");
 
+       if (retval != ERROR_OK)
+               libusb_exit(jtag_libusb_context);
+
        return retval;
 }