[image] Generalise "currently-running script" to "currently-running image"

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/core/image.c

 /** List of registered images */
 struct list_head images = LIST_HEAD_INIT ( images );
 
+/** Currently-executing image */
+struct image *current_image;
+
 /**
  * Free executable image
  *
  * @ret rc		Return status code
  */
 int image_exec ( struct image *image ) {
+	struct image *saved_current_image;
 	struct image *replacement;
 	struct uri *old_cwuri;
 	int rc;
 	old_cwuri = uri_get ( cwuri );
 	churi ( image->uri );
 
+	/* Preserve record of any currently-running image */
+	saved_current_image = current_image;
+
 	/* Take out a temporary reference to the image.  This allows
 	 * the image to unregister itself if necessary, without
 	 * automatically freeing itself.
 	 */
-	image_get ( image );
+	current_image = image_get ( image );
 
 	/* Try executing the image */
 	if ( ( rc = image->type->exec ( image ) ) != 0 ) {
 	/* Drop temporary reference to the original image */
 	image_put ( image );
 
+	/* Restore previous currently-running image */
+	current_image = saved_current_image;
+
 	/* Reset current working directory */
 	churi ( old_cwuri );
 	uri_put ( old_cwuri );

src/image/script.c

 #include <usr/prompt.h>
 #include <ipxe/script.h>
 
-/** Currently running script
- *
- * This is a global in order to allow goto_exec() to update the
- * offset.
- */
-static struct image *script;
-
 /** Offset within current script
  *
  * This is a global in order to allow goto_exec() to update the
 /**
  * Process script lines
  *
+ * @v image		Script
  * @v process_line	Line processor
  * @v terminate		Termination check
  * @ret rc		Return status code
  */
-static int process_script ( int ( * process_line ) ( const char *line ),
+static int process_script ( struct image *image,
+			    int ( * process_line ) ( const char *line ),
 			    int ( * terminate ) ( int rc ) ) {
 	off_t eol;
 	size_t len;
 	do {
 	
 		/* Find length of next line, excluding any terminating '\n' */
-		eol = memchr_user ( script->data, script_offset, '\n',
-				    ( script->len - script_offset ) );
+		eol = memchr_user ( image->data, script_offset, '\n',
+				    ( image->len - script_offset ) );
 		if ( eol < 0 )
-			eol = script->len;
+			eol = image->len;
 		len = ( eol - script_offset );
 
 		/* Copy line, terminate with NUL, and execute command */
 		{
 			char cmdbuf[ len + 1 ];
 
-			copy_from_user ( cmdbuf, script->data,
+			copy_from_user ( cmdbuf, image->data,
 					 script_offset, len );
 			cmdbuf[len] = '\0';
 			DBG ( "$ %s\n", cmdbuf );
 				return rc;
 		}
 
-	} while ( script_offset < script->len );
+	} while ( script_offset < image->len );
 
 	return rc;
 }
  * @ret rc		Return status code
  */
 static int script_exec ( struct image *image ) {
-	struct image *saved_script;
 	size_t saved_offset;
 	int rc;
 
 	unregister_image ( image );
 
 	/* Preserve state of any currently-running script */
-	saved_script = script;
 	saved_offset = script_offset;
 
-	/* Initialise state for this script */
-	script = image;
-
 	/* Process script */
-	rc = process_script ( script_exec_line, terminate_on_exit_or_failure );
+	rc = process_script ( image, script_exec_line,
+			      terminate_on_exit_or_failure );
 
 	/* Restore saved state, re-register image, and return */
 	script_offset = saved_offset;
-	script = saved_script;
 	register_image ( image );
 	return rc;
 }
 		return rc;
 
 	/* Sanity check */
-	if ( ! script ) {
+	if ( ! current_image ) {
 		rc = -ENOTTY;
 		printf ( "Not in a script: %s\n", strerror ( rc ) );
 		return rc;
 
 	/* Find label */
 	saved_offset = script_offset;
-	if ( ( rc = process_script ( goto_find_label,
+	if ( ( rc = process_script ( current_image, goto_find_label,
 				     terminate_on_label_found ) ) != 0 ) {
 		script_offset = saved_offset;
 		return rc;

src/include/ipxe/image.h

 #define __image_type( probe_order ) __table_entry ( IMAGE_TYPES, probe_order )
 
 extern struct list_head images;
+extern struct image *current_image;
 
 /** Iterate over all registered images */
 #define for_each_image( image ) \