From 9cf0574418cc7657618a738dd31337739c635875 Mon Sep 17 00:00:00 2001

From: Mark McLoughlin <markmc@redhat.com>

Date: Fri, 3 Jul 2009 09:17:20 +0100

Subject: [PATCH] Prefer sysfs for USB host devices

Scanning for devices via /sys/bus/usb/devices/ and using them via the

/dev/bus/usb/<bus>/<device> character devices is the prefered method

on modern kernels, so try that first.

When using SELinux and libvirt, qemu will have access to /sys/bus/usb

but not /proc/bus/usb, so although the current code will work just

fine, it will generate SELinux AVC warnings.

See also:

  https://bugzilla.redhat.com/508326

Reported-by: Daniel Berrange <berrange@redhat.com>

Signed-off-by: Mark McLoughlin <markmc@redhat.com>

---

 usb-linux.c |   18 +++++++++---------

 1 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/usb-linux.c b/usb-linux.c

index 67e4acd..3c724ba 100644

--- a/usb-linux.c

+++ b/usb-linux.c

@@ -1265,6 +1265,15 @@ static int usb_host_scan(void *opaque, USBScanFunc *func)

     /* only check the host once */

     if (!usb_fs_type) {

+        dir = opendir(USBSYSBUS_PATH "/devices");

+        if (dir) {

+            /* devices found in /dev/bus/usb/ (yes - not a mistake!) */

+            strcpy(devpath, USBDEVBUS_PATH);

+            usb_fs_type = USB_FS_SYS;

+            closedir(dir);

+            dprintf(USBDBG_DEVOPENED, USBSYSBUS_PATH);

+            goto found_devices;

+        }

         f = fopen(USBPROCBUS_PATH "/devices", "r");

         if (f) {

             /* devices found in /proc/bus/usb/ */

@@ -1284,15 +1293,6 @@ static int usb_host_scan(void *opaque, USBScanFunc *func)

             dprintf(USBDBG_DEVOPENED, USBDEVBUS_PATH);

             goto found_devices;

         }

-        dir = opendir(USBSYSBUS_PATH "/devices");

-        if (dir) {

-            /* devices found in /dev/bus/usb/ (yes - not a mistake!) */

-            strcpy(devpath, USBDEVBUS_PATH);

-            usb_fs_type = USB_FS_SYS;

-            closedir(dir);

-            dprintf(USBDBG_DEVOPENED, USBSYSBUS_PATH);

-            goto found_devices;

-        }

     found_devices:

         if (!usb_fs_type) {

             monitor_printf(mon, "husb: unable to access USB devices\n");

-- 

1.6.2.5