1 files changed, 24 insertions, 2 deletions

diff --git a/int2tap.c b/int2tap.c
index ccfce7f..d38b63a 100644
--- a/int2tap.c
+++ b/int2tap.c
@@ -54,10 +54,28 @@ static void Usage(void)
 {
     fprintf(stderr,"%s: usage %s [-b] [-s] [-a addr] [-c addr] "
     			"output-file input-file ... \n",progname,progname);
+
     exit(EXIT_FAILURE);
 }
 
 
+static unsigned ToUnsigned(const char *p)
+{
+    char *end;
+    unsigned u;
+
+    u=(unsigned)strtoul(p,&end,0);
+
+    if (end==p || *end!=0)
+    {
+    	fprintf(stderr,"%s: invalid number %s\n",progname,p);
+	exit(EXIT_FAILURE);
+    }
+
+    return u;
+}
+
+
 /* ---------------------------------------- MAIN
 */
 int main(int argc, char *argv[])
@@ -108,6 +126,10 @@ int main(int argc, char *argv[])
 	{
 	    switch(argv[f][1])
 	    {
+		case 'h':
+		    Usage();
+		    break;
+
 	    	case 'b':
 		    bin_only=TRUE;
 		    break;
@@ -123,7 +145,7 @@ int main(int argc, char *argv[])
 		    }
 
 		    addr_defined=TRUE;
-		    exec_addr=(unsigned)strtoul(argv[++f],NULL,0);
+		    exec_addr=ToUnsigned(argv[++f]);
 
 		    break;
 
@@ -134,7 +156,7 @@ int main(int argc, char *argv[])
 		    }
 
 		    clear_defined=TRUE;
-		    clear_addr=(unsigned)strtoul(argv[++f],NULL,0);
+		    clear_addr=ToUnsigned(argv[++f]);
 
 		    break;