1 files changed, 27 insertions, 19 deletions
diff --git a/tools/compile_seccomp_policy.py b/tools/compile_seccomp_policy.py
index f3b9eea..f2b714b 100755
--- a/tools/compile_seccomp_policy.py
+++ b/tools/compile_seccomp_policy.py
@@ -23,6 +23,7 @@ BPF program suitable for use with Minijail in the current architecture.
 from __future__ import print_function
 
 import argparse
+import os
 import sys
 
 try:
@@ -36,35 +37,39 @@ except ImportError:
     from minijail import compiler
     from minijail import parser
 
+CONSTANTS_ERR_MSG = """Could not find 'constants.json' file.
+See 'generate_constants_json.py -h'."""
+
 
 def parse_args(argv):
     """Return the parsed CLI arguments for this tool."""
-    parser = argparse.ArgumentParser(description=__doc__)
-    parser.add_argument(
-        '--optimization-strategy',
-        default=compiler.OptimizationStrategy.BST,
-        type=compiler.OptimizationStrategy,
-        choices=list(compiler.OptimizationStrategy))
-    parser.add_argument('--include-depth-limit', default=10)
-    parser.add_argument('--arch-json', default='constants.json')
-    parser.add_argument(
+    arg_parser = argparse.ArgumentParser(description=__doc__)
+    arg_parser.add_argument('--optimization-strategy',
+                            default=compiler.OptimizationStrategy.BST,
+                            type=compiler.OptimizationStrategy,
+                            choices=list(compiler.OptimizationStrategy))
+    arg_parser.add_argument('--include-depth-limit', default=10)
+    arg_parser.add_argument('--arch-json', default='constants.json')
+    arg_parser.add_argument(
         '--default-action',
         type=str,
         help=('Use the specified default action, overriding any @default '
               'action found in the .policy files. '
-              'This allows the use of permissive actions (allow, log, trace) '
-              'since it is not valid to specify a permissive action in '
-              '.policy files. This is useful for debugging.'))
-    parser.add_argument(
+              'This allows the use of permissive actions (allow, log, trace, '
+              'user-notify) since it is not valid to specify a permissive '
+              'action in .policy files. This is useful for debugging.'))
+    arg_parser.add_argument(
         '--use-kill-process',
         action='store_true',
         help=('Use SECCOMP_RET_KILL_PROCESS instead of '
               'SECCOMP_RET_KILL_THREAD (requires Linux v4.14+).'))
-    parser.add_argument(
-        'policy', help='The seccomp policy.', type=argparse.FileType('r'))
-    parser.add_argument(
-        'output', help='The BPF program.', type=argparse.FileType('wb'))
-    return parser.parse_args(argv)
+    arg_parser.add_argument('policy',
+                            help='The seccomp policy.',
+                            type=argparse.FileType('r'))
+    arg_parser.add_argument('output',
+                            help='The BPF program.',
+                            type=argparse.FileType('wb'))
+    return arg_parser.parse_args(argv), arg_parser
 
 
 def main(argv=None):
@@ -73,7 +78,10 @@ def main(argv=None):
     if argv is None:
         argv = sys.argv[1:]
 
-    opts = parse_args(argv)
+    opts, arg_parser = parse_args(argv)
+    if not os.path.exists(opts.arch_json):
+        arg_parser.error(CONSTANTS_ERR_MSG)
+
     parsed_arch = arch.Arch.load_from_json(opts.arch_json)
     policy_compiler = compiler.PolicyCompiler(parsed_arch)
     if opts.use_kill_process: