[PATCH V6 4/7] libxl: add libxl_device_usb_assignable_list API

[Chunyan Liu <cyliu@suse.com>]

Add API for listing assignable USB devices info.
Assignable USB device means the USB device type is assignable and
it's not assigned to any guest yet.

Signed-off-by: Chunyan Liu <cyliu@suse.com>
---
This could be squashed with previous patch. Split because there is
some dispute on this. If this is acceptable, could be squashed,
otherwise could be removed.

 tools/libxl/libxl.h       |  3 +++
 tools/libxl/libxl_pvusb.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 56 insertions(+)

diff --git a/tools/libxl/libxl.h b/tools/libxl/libxl.h
index 05b6331..d1360ce 100644
--- a/tools/libxl/libxl.h
+++ b/tools/libxl/libxl.h
@@ -1433,6 +1433,9 @@ int libxl_device_usbctrl_getinfo(libxl_ctx *ctx, uint32_t domid,
                                  libxl_usbctrlinfo *usbctrlinfo);
 
 /* USB Devices */
+libxl_device_usb *
+libxl_device_usb_assignable_list(libxl_ctx *ctx, int *num);
+
 int libxl_device_usb_add(libxl_ctx *ctx, uint32_t domid, libxl_device_usb *usb,
                          const libxl_asyncop_how *ao_how)
                          LIBXL_EXTERNAL_CALLERS_ONLY;
diff --git a/tools/libxl/libxl_pvusb.c b/tools/libxl/libxl_pvusb.c
index d4c4c03..e56fa07 100644
--- a/tools/libxl/libxl_pvusb.c
+++ b/tools/libxl/libxl_pvusb.c
@@ -552,6 +552,59 @@ static bool is_usb_assignable(libxl__gc *gc, libxl_device_usb *usb)
     return classcode != USBHUB_CLASS_CODE;
 }
 
+libxl_device_usb *
+libxl_device_usb_assignable_list(libxl_ctx *ctx, int *num)
+{
+    GC_INIT(ctx);
+    libxl_device_usb *usbs = NULL;
+    libxl_device_usb *assigned;
+    int num_assigned;
+    struct dirent *de;
+    DIR *dir;
+
+    *num = 0;
+
+    if (libxl__device_usb_assigned_list(gc, &assigned, &num_assigned) < 0)
+        goto out;
+
+    if (!(dir = opendir(SYSFS_USB_DEV)))
+        goto out;
+
+    while ((de = readdir(dir))) {
+        libxl_device_usb *usb;
+        int bus = -1, addr = -1;
+
+        if (!de->d_name)
+            continue;
+
+        usb_busaddr_from_busid(gc, de->d_name, &bus, &addr);
+        if (bus < 1 || addr < 1)
+            continue;
+
+        GCNEW(usb);
+        usb->u.hostdev.hostbus = bus;
+        usb->u.hostdev.hostaddr = addr;
+
+        if (!is_usb_assignable(gc, usb))
+            continue;
+
+        if (is_usb_in_array(assigned, num_assigned, usb))
+            continue;
+
+        usbs = libxl__realloc(NOGC, usbs, sizeof(*usbs) * (*num + 1));
+        libxl_device_usb_init(usbs + *num);
+        usbs[*num].u.hostdev.hostbus = bus;
+        usbs[*num].u.hostdev.hostaddr = addr;
+        (*num)++;
+    }
+
+    closedir(dir);
+
+out:
+    GC_FREE;
+    return usbs;
+}
+
 /* get usb devices under certain usb controller */
 static int
 libxl__device_usb_list_per_usbctrl(libxl__gc *gc, uint32_t domid,
-- 
2.1.4