[#2788] exhaust options before throwing error

Prior to this change, if parseArgs() was called twice during the same
program lifetime and it stumbled on an unsupported option and throwed an
exception on the first call, the previous set of arguments lived on to
be parsed by the second call. This is a situation that likely arises
only in unit tests, but let us fix it properly to at least silence the unit
test failure on alpine, which was happening because of different
implementation of getopt from musl, and which motivated looking into how
getopt behaves. To make the bug evident even in a non-alpine environment, add an
EXPECT_THROW_MSG in DStubControllerTest.commandLineArgs when parsing argv3, and
see that it outputs "unsupported option: [s]" instead of
"extraneous command line information".

Author: andrei-pavel

src/bin/agent/tests/ca_controller_unittests.cc

@@ -216,7 +216,7 @@ TEST_F(CtrlAgentControllerTest, commandLineArgs) {
     char* argv2[] = { const_cast<char*>("progName"),
                       const_cast<char*>("-x") };
     argc = 2;
-    EXPECT_THROW_MSG(parseArgs(argc, argv2), InvalidUsage, "unsupported option: [x] ");
+    EXPECT_THROW_MSG(parseArgs(argc, argv2), InvalidUsage, "unsupported option: -x");
 }
 
 // Tests application process creation and initialization.

src/bin/d2/tests/d2_controller_unittests.cc

@@ -132,7 +132,7 @@ TEST_F(D2ControllerTest, commandLineArgs) {
     char* argv2[] = { const_cast<char*>("progName"),
                       const_cast<char*>("-x") };
     argc = 2;
-    EXPECT_THROW_MSG(parseArgs(argc, argv2), InvalidUsage, "unsupported option: [x] ");
+    EXPECT_THROW_MSG(parseArgs(argc, argv2), InvalidUsage, "unsupported option: -x");
 }
 
 /// @brief Tests application process creation and initialization.

src/bin/netconf/tests/netconf_controller_unittests.cc

@@ -131,7 +131,7 @@ TEST_F(NetconfControllerTest, commandLineArgs) {
     char* argv2[] = { const_cast<char*>("progName"),
                       const_cast<char*>("-x") };
     argc = 2;
-    EXPECT_THROW_MSG(parseArgs(argc, argv2), InvalidUsage, "unsupported option: [x] ");
+    EXPECT_THROW_MSG(parseArgs(argc, argv2), InvalidUsage, "unsupported option: -x");
 }
 
 // Tests application process creation and initialization.

src/lib/process/d_controller.cc

@@ -293,21 +293,33 @@ DControllerBase::parseArgs(int argc, char* argv[]) {
             break;
 
         case '?': {
+            char const saved_optopt(optopt);
+            std::string const saved_optarg(optarg ? optarg : std::string());
+
+            // Exhaust all remaining options in case parseArgs() is called again.
+            while (getopt(argc, argv, opts.c_str()) != -1) {
+            }
+
             // We hit an invalid option.
-            isc_throw(InvalidUsage, "unsupported option: ["
-                      << static_cast<char>(optopt) << "] "
-                      << (!optarg ? "" : optarg));
+            isc_throw(InvalidUsage, "unsupported option: -" << saved_optopt <<
+                      (saved_optarg.empty() ? std::string() : " " + saved_optarg));
 
             break;
             }
 
         default:
             // We hit a valid custom option
             if (!customOption(ch, optarg)) {
-                // This would be a programmatic error.
-                isc_throw(InvalidUsage, " Option listed but implemented?: ["
-                          << static_cast<char>(ch) << "] "
-                          << (!optarg ? "" : optarg));
+                char const saved_optopt(optopt);
+                std::string const saved_optarg(optarg ? optarg : std::string());
+
+                // Exhaust all remaining options in case parseArgs() is called again.
+                while (getopt(argc, argv, opts.c_str()) != -1) {
+                }
+
+                // We hit an invalid option.
+                isc_throw(InvalidUsage, "unsupported option: -" << saved_optopt <<
+                        (saved_optarg.empty() ? std::string() : " " + saved_optarg));
             }
             break;
         }

src/lib/process/tests/d_controller_unittests.cc

@@ -99,14 +99,14 @@ TEST_F(DStubControllerTest, commandLineArgs) {
     char* argv2[] = { const_cast<char*>("progName"),
                       const_cast<char*>("-bs") };
     argc = 2;
-    EXPECT_THROW_MSG(parseArgs(argc, argv2), InvalidUsage, "unsupported option: [b] ");
+    EXPECT_THROW_MSG(parseArgs(argc, argv2), InvalidUsage, "unsupported option: -b");
 
     // Verify that extraneous information is detected.
     char* argv3[] = { const_cast<char*>("progName"),
                       const_cast<char*>("extra"),
                       const_cast<char*>("information") };
     argc = 3;
-    EXPECT_THROW_MSG(parseArgs(argc, argv3), InvalidUsage, "unsupported option: [s] ");
+    EXPECT_THROW_MSG(parseArgs(argc, argv3), InvalidUsage, "extraneous command line information");
 }
 
 /// @brief Tests application process creation and initialization.