usertools: add error on missing driver to bind

A common user error is to forget driver to which the PCI devices should
be bound to. Currently, the error message in this case looks unhelpful
misleading and indecipherable to anyone but people who know how devbind
works.

Fix this by checking if the driver string is actually a valid device
string. If it is, we assume that the user has just forgot to specify the
driver, and display appropriate error. We also assume that no one will
name their driver in a format that looks like a PCI address, but that
seems like a reasonable assumption to make.

Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>

diff --git a/usertools/dpdk-devbind.py b/usertools/dpdk-devbind.py
index 542ecff..b32506e 100755 (executable)
--- a/usertools/dpdk-devbind.py
+++ b/usertools/dpdk-devbind.py
@@ -342,9 +342,8 @@ def dev_id_from_dev_name(dev_name):
             if dev_name in devices[d]["Interface"].split(","):
                 return devices[d]["Slot"]
     # if nothing else matches - error
-    print("Unknown device: %s. "
-          "Please specify device in \"bus:slot.func\" format" % dev_name)
-    sys.exit(1)
+    raise ValueError("Unknown device: %s. "
+                     "Please specify device in \"bus:slot.func\" format" % dev_name)
 
 
 def unbind_one(dev_id, force):
@@ -493,7 +492,12 @@ def unbind_all(dev_list, force=False):
                     unbind_one(devices[d]["Slot"], force)
         return
 
-    dev_list = map(dev_id_from_dev_name, dev_list)
+    try:
+        dev_list = map(dev_id_from_dev_name, dev_list)
+    except ValueError as ex:
+        print(ex)
+        sys.exit(1)
+
     for d in dev_list:
         unbind_one(d, force)
 
@@ -502,7 +506,23 @@ def bind_all(dev_list, driver, force=False):
     """Bind method, takes a list of device locations"""
     global devices
 
-    dev_list = map(dev_id_from_dev_name, dev_list)
+    # a common user error is to forget to specify the driver the devices need to
+    # be bound to. check if the driver is a valid device, and if it is, show
+    # a meaningful error.
+    try:
+        dev_id_from_dev_name(driver)
+        # if we've made it this far, this means that the "driver" was a valid
+        # device string, so it's probably not a valid driver name.
+        sys.exit("Error: Driver '%s' does not look like a valid driver. " \
+                 "Did you forget to specify the driver to bind devices to?" % driver)
+    except ValueError:
+        # driver generated error - it's not a valid device ID, so all is well
+        pass
+
+    try:
+        dev_list = map(dev_id_from_dev_name, dev_list)
+    except ValueError as ex:
+        sys.exit(ex)
 
     for d in dev_list:
         bind_one(d, driver, force)