Give better error message on bad arguments

Instead of just printing the huge usage text and hoping the user figures out what was wrong.
TigerVNC · Dec 3, 2024 · 16a9529 · 16a9529
1 parent 8800e39
commit 16a9529
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Showing 4 changed files with 53 additions and 11 deletions.
diff --git a/unix/vncconfig/vncconfig.cxx b/unix/vncconfig/vncconfig.cxx
@@ -296,18 +296,34 @@ int main(int argc, char** argv)
         if (i >= argc) usage();
 
         char* equal = strchr(argv[i], '=');
-        if (!equal)
-          usage();
+        if (!equal) {
+          fprintf(stderr, "%s: Invalid parameter syntax '%s'\n",
+                  programName, argv[i]);
+          fprintf(stderr, "See '%s -help' for more information.\n",
+                  programName);
+          exit(1);
+        }
 
         std::string name(argv[i], equal-argv[i]);
         std::string value(equal+1);
 
         if (!XVncExtSetParam(dpy, name.c_str(), value.c_str()))
           fprintf(stderr, "Setting param %s failed\n",argv[i]);
+      } else if (argv[i][0] == '-') {
+        fprintf(stderr, "%s: Unrecognized option '%s'\n",
+                programName, argv[i]);
+        fprintf(stderr, "See '%s -help' for more information.\n",
+                programName);
+        exit(1);
       } else {
         char* equal = strchr(argv[i], '=');
-        if (!equal)
-          usage();
+        if (!equal) {
+          fprintf(stderr, "%s: Invalid parameter syntax '%s'\n",
+                  programName, argv[i]);
+          fprintf(stderr, "See '%s -help' for more information.\n",
+                  programName);
+          exit(1);
+        }
 
         std::string name(argv[i], equal-argv[i]);
         std::string value(equal+1);

diff --git a/unix/vncpasswd/vncpasswd.cxx b/unix/vncpasswd/vncpasswd.cxx
@@ -202,15 +202,19 @@ int main(int argc, char** argv)
     } else if (strncmp(argv[i], "-f", 2) == 0) {
       return encrypt_pipe();
     } else if (argv[i][0] == '-') {
-      usage();
+      fprintf(stderr, "%s: Unrecognized option '%s'\n", prog, argv[i]);
+      fprintf(stderr, "See '%s --help' for more information.\n", prog);
+      exit(1);
     } else if (fname[0] == '\0') {
       if (strlen(argv[i]) >= sizeof(fname)) {
         fprintf(stderr, "Too long filename specified\n");
         return -1;
       }
       strcpy(fname, argv[i]);
     } else {
-      usage();
+      fprintf(stderr, "%s: Extra argument '%s'\n", prog, argv[i]);
+      fprintf(stderr, "See '%s --help' for more information.\n", prog);
+      exit(1);
     }
   }
 

diff --git a/unix/x0vncserver/x0vncserver.cxx b/unix/x0vncserver/x0vncserver.cxx
@@ -307,7 +307,18 @@ int main(int argc, char** argv)
       return 0;
     }
 
-    usage();
+    if (argv[i][0] == '-') {
+      fprintf(stderr, "%s: Unrecognized option '%s'\n",
+              programName, argv[i]);
+      fprintf(stderr, "See '%s --help' for more information.\n",
+              programName);
+      exit(1);
+    }
+
+    fprintf(stderr, "%s: Extra argument '%s'\n", programName, argv[i]);
+    fprintf(stderr, "See '%s --help' for more information.\n",
+            programName);
+    exit(1);
   }
 
   if (!(dpy = XOpenDisplay(displayname))) {

diff --git a/vncviewer/vncviewer.cxx b/vncviewer/vncviewer.cxx
@@ -694,11 +694,22 @@ int main(int argc, char** argv)
       return 0;
     }
 
-    if (argv[i][0] == '-')
-      usage(argv[0]);
+    if (argv[i][0] == '-') {
+      fprintf(stderr, "\n");
+      fprintf(stderr, "%s: Unrecognized option '%s'\n",
+              argv[0], argv[i]);
+      fprintf(stderr, "See '%s --help' for more information.\n",
+              argv[0]);
+      exit(1);
+    }
 
-    if (vncServerName[0] != '\0')
-      usage(argv[0]);
+    if (vncServerName[0] != '\0') {
+      fprintf(stderr, "\n");
+      fprintf(stderr, "%s: Extra argument '%s'\n", argv[0], argv[i]);
+      fprintf(stderr, "See '%s --help' for more information.\n",
+              argv[0]);
+      exit(0);
+    }
 
     strncpy(vncServerName, argv[i], VNCSERVERNAMELEN);
     vncServerName[VNCSERVERNAMELEN - 1] = '\0';