Fix FreeBSD issue with libusb_get_port_numbers()

Currently (as of date 20150122) an ioctl problem within the
FreeBSD kernel is preventing libusb_get_port_numbers() from working.
Hence calls to libusb_get_port_numbers() will always return 0.
This makes it impossible to establish a physical path the the usb device.

This problem has existed "forever" -
meaning that libusb_get_port_numbers() has never worked.

A fix is committed to FreeBSD "current" head  -
and will later be merged (MFC'ed) to maintenance branches.
See: https://svnweb.freebsd.org/base?view=revision&revision=277417

Additionally FreeBSD requires that devices prior to calling
libusb_get_port_numbers() have been opened with libusb_open().

The patch is "forwards-compatible".
Currently it acts specificly to libusb_get_port_numbers()
currently returning 0 on FreeBSD.
In these situations it constructs an artificial path to the device.
When FreeBSD kernels appears with proper working ioctl
supporting libusb_get_port_numbers() the code will construct
proper physical paths for newer kernels - while still generating
artificial physical paths for older defective kernels.

diff --git a/src/usb.c b/src/usb.c
index 8bdb8d60d07e36f794aefb99bf2298fcefb0bb99..9c34b38ad1bdb204d89c5a16f2631c11fb7617f0 100644 (file)
--- a/src/usb.c
+++ b/src/usb.c
@@ -276,8 +276,27 @@ SR_PRIV int usb_get_port_path(libusb_device *dev, char *path, int path_len)
        uint8_t port_numbers[8];
        int i, n, len;
 
+/*
+ * FreeBSD requires that devices prior to calling libusb_get_port_numbers()
+ * have been opened with libusb_open().
+ */
+#ifdef __FreeBSD__
+       struct libusb_device_handle *devh;
+       if (libusb_open(dev, &devh) != 0)
+               return SR_ERR;
+#endif
        n = libusb_get_port_numbers(dev, port_numbers, sizeof(port_numbers));
+#ifdef __FreeBSD__
+       libusb_close(devh);
+#endif
 
+/* Workaround FreeBSD libusb_get_port_numbers() returning 0. */
+#ifdef __FreeBSD__
+       if (n == 0) {
+               port_numbers[0] = libusb_get_device_address(dev);
+               n = 1;
+       }
+#endif
        if (n < 1)
                return SR_ERR;