usertools: print binding errors to stderr

Bring consistency to error messages and output them to stderr.
Also, whenever the script tells the user to "check usage", don't
tell the user to do it and just display usage instead.

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

diff --git a/usertools/dpdk-devbind.py b/usertools/dpdk-devbind.py
index d3b1624..7b5cbc1 100755 (executable)
--- a/usertools/dpdk-devbind.py
+++ b/usertools/dpdk-devbind.py
@@ -3,6 +3,7 @@
 # Copyright(c) 2010-2014 Intel Corporation
 #
 
+from __future__ import print_function
 import sys
 import os
 import getopt
@@ -185,7 +186,7 @@ def check_modules():
 
     # check if we have at least one loaded module
     if True not in [mod["Found"] for mod in mods] and b_flag is not None:
-        print("Warning: no supported DPDK kernel modules are loaded")
+        print("Warning: no supported DPDK kernel modules are loaded", file=sys.stderr)
 
     # change DPDK driver list to only contain drivers that are loaded
     dpdk_drivers = [mod["Name"] for mod in mods if mod["Found"]]
@@ -352,14 +353,14 @@ def unbind_one(dev_id, force):
     '''Unbind the device identified by "dev_id" from its current driver'''
     dev = devices[dev_id]
     if not has_driver(dev_id):
-        print("%s %s %s is not currently managed by any driver\n" %
-              (dev["Slot"], dev["Device_str"], dev["Interface"]))
+        print("Notice: %s %s %s is not currently managed by any driver" %
+              (dev["Slot"], dev["Device_str"], dev["Interface"]), file=sys.stderr)
         return
 
     # prevent us disconnecting ourselves
     if dev["Ssh_if"] and not force:
-        print("Routing table indicates that interface %s is active. "
-              "Skipping unbind" % (dev_id))
+        print("Warning: routing table indicates that interface %s is active. "
+              "Skipping unbind" % dev_id, file=sys.stderr)
         return
 
     # write to /sys to unbind
@@ -367,9 +368,8 @@ def unbind_one(dev_id, force):
     try:
         f = open(filename, "a")
     except:
-        print("Error: unbind failed for %s - Cannot open %s"
-              % (dev_id, filename))
-        sys.exit(1)
+        sys.exit("Error: unbind failed for %s - Cannot open %s" %
+                 (dev_id, filename))
     f.write(dev_id)
     f.close()
 
@@ -382,15 +382,15 @@ def bind_one(dev_id, driver, force):
 
     # prevent disconnection of our ssh session
     if dev["Ssh_if"] and not force:
-        print("Routing table indicates that interface %s is active. "
-              "Not modifying" % (dev_id))
+        print("Warning: routing table indicates that interface %s is active. "
+              "Not modifying" % dev_id, file=sys.stderr)
         return
 
     # unbind any existing drivers we don't want
     if has_driver(dev_id):
         if dev["Driver_str"] == driver:
-            print("%s already bound to driver %s, skipping\n"
-                  % (dev_id, driver))
+            print("Notice: %s already bound to driver %s, skipping" %
+                  (dev_id, driver), file=sys.stderr)
             return
         else:
             saved_driver = dev["Driver_str"]
@@ -410,14 +410,14 @@ def bind_one(dev_id, driver, force):
                 f = open(filename, "w")
             except:
                 print("Error: bind failed for %s - Cannot open %s"
-                      % (dev_id, filename))
+                      % (dev_id, filename), file=sys.stderr)
                 return
             try:
                 f.write("%s" % driver)
                 f.close()
             except:
                 print("Error: bind failed for %s - Cannot write driver %s to "
-                      "PCI ID " % (dev_id, driver))
+                      "PCI ID " % (dev_id, driver), file=sys.stderr)
                 return
         # For kernels < 3.15 use new_id to add PCI id's to the driver
         else:
@@ -426,7 +426,7 @@ def bind_one(dev_id, driver, force):
                 f = open(filename, "w")
             except:
                 print("Error: bind failed for %s - Cannot open %s"
-                      % (dev_id, filename))
+                      % (dev_id, filename), file=sys.stderr)
                 return
             try:
                 # Convert Device and Vendor Id to int to write to new_id
@@ -435,7 +435,7 @@ def bind_one(dev_id, driver, force):
                 f.close()
             except:
                 print("Error: bind failed for %s - Cannot write new PCI ID to "
-                      "driver %s" % (dev_id, driver))
+                      "driver %s" % (dev_id, driver), file=sys.stderr)
                 return
 
     # do the bind by writing to /sys
@@ -444,7 +444,7 @@ def bind_one(dev_id, driver, force):
         f = open(filename, "a")
     except:
         print("Error: bind failed for %s - Cannot open %s"
-              % (dev_id, filename))
+              % (dev_id, filename), file=sys.stderr)
         if saved_driver is not None:  # restore any previous driver
             bind_one(dev_id, saved_driver, force)
         return
@@ -459,7 +459,7 @@ def bind_one(dev_id, driver, force):
         if "Driver_str" in tmp and tmp["Driver_str"] == driver:
             return
         print("Error: bind failed for %s - Cannot bind to driver %s"
-              % (dev_id, driver))
+              % (dev_id, driver), file=sys.stderr)
         if saved_driver is not None:  # restore any previous driver
             bind_one(dev_id, saved_driver, force)
         return
@@ -472,16 +472,14 @@ def bind_one(dev_id, driver, force):
         try:
             f = open(filename, "w")
         except:
-            print("Error: unbind failed for %s - Cannot open %s"
+            sys.exit("Error: unbind failed for %s - Cannot open %s"
                   % (dev_id, filename))
-            sys.exit(1)
         try:
             f.write("\00")
             f.close()
         except:
-            print("Error: unbind failed for %s - Cannot open %s"
+            sys.exit("Error: unbind failed for %s - Cannot open %s"
                   % (dev_id, filename))
-            sys.exit(1)
 
 
 def unbind_all(dev_list, force=False):
@@ -676,8 +674,7 @@ def parse_args():
             force_flag = True
         if opt == "-b" or opt == "-u" or opt == "--bind" or opt == "--unbind":
             if b_flag is not None:
-                print("Error - Only one bind or unbind may be specified\n")
-                sys.exit(1)
+                sys.exit("Error: binding and unbinding are mutually exclusive")
             if opt == "-u" or opt == "--unbind":
                 b_flag = "none"
             else:
@@ -692,14 +689,14 @@ def do_arg_actions():
     global args
 
     if b_flag is None and not status_flag:
-        print("Error: No action specified for devices."
-              "Please give a -b or -u option")
-        print("Run '%s --usage' for further information" % sys.argv[0])
+        print("Error: No action specified for devices. "
+              "Please give a -b or -u option", file=sys.stderr)
+        usage()
         sys.exit(1)
 
     if b_flag is not None and len(args) == 0:
-        print("Error: No devices specified.")
-        print("Run '%s --usage' for further information" % sys.argv[0])
+        print("Error: No devices specified.", file=sys.stderr)
+        usage()
         sys.exit(1)
 
     if b_flag == "none" or b_flag == "None":
@@ -727,8 +724,7 @@ def main():
         ret = subprocess.call(['which', 'lspci'],
                               stdout=devnull, stderr=devnull)
         if ret != 0:
-            print("'lspci' not found - please install 'pciutils'")
-            sys.exit(1)
+            sys.exit("'lspci' not found - please install 'pciutils'")
     parse_args()
     check_modules()
     clear_data()