[script] Allow for DOS-style line endings in scripts

Windows text editors such as Notepad tend to use CRLF line endings,
which breaks gPXE's signature detection for script images.  Since
scripts are usually very small, they end up falling back to being
detected as valid PXE executable images (since there are no signature
checks for PXE executables).  Executing text files as x86 machine code
tends not to work well.

Fix by allowing for any isspace() character to terminate the "#!gpxe"
signature, and by ensuring that CR characters get stripped during
command line parsing.

Suggested-by: Shao Miller <Shao.Miller@yrdsb.edu.on.ca>

src/core/ctype.c

@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2009 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+/**
+ * @file
+ *
+ * Character types
+ *
+ */
+
+#include <ctype.h>
+
+/**
+ * Check to see if character is a space
+ *
+ * @v c			Character
+ * @ret isspace		Character is a space
+ */
+int isspace ( int c ) {
+	switch ( c ) {
+	case ' ' :
+	case '\f' :
+	case '\n' :
+	case '\r' :
+	case '\t' :
+	case '\v' :
+		return 1;
+	default:
+		return 0;
+	}
+}

src/core/exec.c

@@ -22,6 +22,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
 #include <string.h>
 #include <stdlib.h>
 #include <stdio.h>
+#include <ctype.h>
 #include <unistd.h>
 #include <getopt.h>
 #include <errno.h>
@@ -170,7 +171,7 @@ static int split_args ( char *args, char * argv[] ) {
 
 	while ( 1 ) {
 		/* Skip over any whitespace / convert to NUL */
-		while ( *args == ' ' ) {
+		while ( isspace ( *args ) ) {
 			if ( argv )
 				*args = '\0';
 			args++;
@@ -183,7 +184,7 @@ static int split_args ( char *args, char * argv[] ) {
 			argv[argc] = args;
 		argc++;
 		/* Skip to start of next whitespace, if any */
-		while ( *args && ( *args != ' ' ) ) {
+		while ( *args && ! isspace ( *args ) ) {
 			args++;
 		}
 	}

src/core/misc.c

@@ -5,6 +5,7 @@ MISC Support Routines
 FILE_LICENCE ( GPL2_OR_LATER );
 
 #include <stdlib.h>
+#include <ctype.h>
 #include <byteswap.h>
 #include <gpxe/in.h>
 #include <gpxe/timer.h>
@@ -32,20 +33,6 @@ int inet_aton ( const char *cp, struct in_addr *inp ) {
 	return 0;
 }
 
-int isspace ( int c ) {
-	switch ( c ) {
-	case ' ':
-	case '\f':
-	case '\n':
-	case '\r':
-	case '\t':
-	case '\v':
-		return 1;
-	default:
-		return 0;
-	}
-}
-
 unsigned long strtoul ( const char *p, char **endp, int base ) {
 	unsigned long ret = 0;
 	unsigned int charval;

src/image/script.c

@@ -27,6 +27,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
 
 #include <string.h>
 #include <stdlib.h>
+#include <ctype.h>
 #include <errno.h>
 #include <gpxe/image.h>
 
@@ -90,8 +91,8 @@ static int script_exec ( struct image *image ) {
  * @ret rc		Return status code
  */
 static int script_load ( struct image *image ) {
-	static const char magic[] = "#!gpxe\n";
-	char test[ sizeof ( magic ) - 1 ];
+	static const char magic[] = "#!gpxe";
+	char test[ sizeof ( magic ) - 1 /* NUL */ + 1 /* terminating space */];
 
 	/* Sanity check */
 	if ( image->len < sizeof ( test ) ) {
@@ -101,7 +102,8 @@ static int script_load ( struct image *image ) {
 
 	/* Check for magic signature */
 	copy_from_user ( test, image->data, 0, sizeof ( test ) );
-	if ( memcmp ( test, magic, sizeof ( test ) ) != 0 ) {
+	if ( ( memcmp ( test, magic, ( sizeof ( test ) - 1 ) ) != 0 ) ||
+	     ! isspace ( test[ sizeof ( test ) - 1 ] ) ) {
 		DBG ( "Invalid magic signature\n" );
 		return -ENOEXEC;
 	}

src/include/ctype.h

@@ -26,4 +26,6 @@ static inline unsigned char toupper(unsigned char c)
 	return c;
 }
 
+extern int isspace ( int c );
+
 #endif /* _CTYPE_H */