Print which arguments were unknown before giving usage message

Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>

2 files changed, 65 insertions, 3 deletions

diff --git a/configure.ac b/configure.ac
index 778ab76..d5f04b2 100644
--- a/configure.ac
+++ b/configure.ac
@@ -36,6 +36,9 @@ m4_ifndef([XORG_MACROS_VERSION],
 XORG_MACROS_VERSION(1.8)
 XORG_DEFAULT_OPTIONS
 
+# Checks for library functions.
+AC_CHECK_FUNCS([strlcat strlcpy])
+
 # Base set of required pkg-config packages
 XLOGO_DEPS="sm xaw7 xmu xt >= 1.0 xext x11"
 
diff --git a/xlogo.c b/xlogo.c
index 1c41f8b..62bc2a3 100644
--- a/xlogo.c
+++ b/xlogo.c
@@ -24,6 +24,30 @@ in this Software without prior written authorization from The Open Group.
 
  */
 
+/*
+ * Copyright (c) 2023, Oracle and/or its affiliates.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+
 #ifdef HAVE_CONFIG_H
 #include <config.h>
 #endif
@@ -38,6 +62,21 @@ in this Software without prior written authorization from The Open Group.
 #endif
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+
+#ifndef HAVE_STRLCAT
+#define strlcat(dst, src, len) do {              \
+    strncat(dst, src, len - strlen(dst) - 1);    \
+    dst[len] = '\0';                             \
+} while(0)
+#endif
+#ifndef HAVE_STRLCPY
+#define strlcpy(dst, src, len) do {              \
+    strncpy(dst, src, len - 1);                  \
+    dst[len] = '\0';                             \
+} while(0)
+#endif
 
 /* Global vars*/
 const char *ProgramName;    /* program name (from argv[0]) */
@@ -96,13 +135,16 @@ save(Widget w, XtPointer client_data, XtPointer call_data)
  */
 
 static void
-Syntax(Widget toplevel)
+Syntax(Widget toplevel, String message)
 {
     Arg arg;
     SmcConn connection;
     String reasons[10];
     int i, n = 0;
 
+    if (message)
+        reasons[n++] = message;
+
     reasons[n++] = "Usage: ";
     reasons[n++] = (String)ProgramName;
     reasons[n++] = " [-fg <color>] [-bg <color>] [-rv] [-bw <pixels>] [-bd <color>]\n";
@@ -113,6 +155,7 @@ Syntax(Widget toplevel)
     reasons[n++] = "             [-render] [-sharp]\n";
 #endif /* XRENDER */
     reasons[n++] = "             [-shape]\n\n";
+    assert(n <= XtNumber(reasons));
 
     XtSetArg(arg, XtNconnection, &connection);
     XtGetValues(toplevel, &arg, (Cardinal)1);
@@ -137,8 +180,24 @@ main(int argc, char *argv[])
 				 options, XtNumber(options),
 				 &argc, argv, fallback_resources,
 				 sessionShellWidgetClass, NULL, ZERO);
-    if (argc != 1)
-	Syntax(toplevel);
+    if (argc != 1) {
+        const char *header = "Unknown argument(s):";
+        char *message;
+        size_t len = strlen(header) + 3; /* 3 for "\n\n\0" */
+        for (int n = 1; n < argc; n++) {
+            len += strlen(argv[n]) + 1;
+	}
+        message = malloc(len);
+        if (message != NULL) {
+            strlcpy(message, header, len);
+            for (int n = 1; n < argc; n++) {
+                strlcat(message, " ", len);
+                strlcat(message, argv[n], len);
+            }
+            strlcat(message, "\n\n", len);
+        }
+	Syntax(toplevel, message);
+    }
 
     XtGetApplicationResources(toplevel, (XtPointer)&userOptions, resources,
                               XtNumber(resources), NULL, 0);