[image] Add "--autofree" option

Allow images to be automatically freed after execution completes
(successfully or otherwise).

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

src/core/image.c

@@ -194,6 +194,10 @@ int register_image ( struct image *image ) {
  */
 void unregister_image ( struct image *image ) {
 
+	/* Do nothing unless image is registered */
+	if ( ! ( image->flags & IMAGE_REGISTERED ) )
+		return;
+
 	DBGC ( image, "IMAGE %s unregistered\n", image->name );
 	list_del ( &image->list );
 	image->flags &= ~IMAGE_REGISTERED;
@@ -259,23 +263,13 @@ int image_probe ( struct image *image ) {
  */
 int image_exec ( struct image *image ) {
 	struct image *saved_current_image;
-	struct image *replacement;
+	struct image *replacement = NULL;
 	struct uri *old_cwuri;
 	int rc;
 
 	/* Sanity check */
 	assert ( image->flags & IMAGE_REGISTERED );
 
-	/* Check that this image can be selected for execution */
-	if ( ( rc = image_select ( image ) ) != 0 )
-		return rc;
-
-	/* Check that image is trusted (if applicable) */
-	if ( require_trusted_images && ! ( image->flags & IMAGE_TRUSTED ) ) {
-		DBGC ( image, "IMAGE %s is not trusted\n", image->name );
-		return -EACCES_UNTRUSTED;
-	}
-
 	/* Switch current working directory to be that of the image itself */
 	old_cwuri = uri_get ( cwuri );
 	churi ( image->uri );
@@ -289,6 +283,17 @@ int image_exec ( struct image *image ) {
 	 */
 	current_image = image_get ( image );
 
+	/* Check that this image can be selected for execution */
+	if ( ( rc = image_select ( image ) ) != 0 )
+		goto err;
+
+	/* Check that image is trusted (if applicable) */
+	if ( require_trusted_images && ! ( image->flags & IMAGE_TRUSTED ) ) {
+		DBGC ( image, "IMAGE %s is not trusted\n", image->name );
+		rc = -EACCES_UNTRUSTED;
+		goto err;
+	}
+
 	/* Record boot attempt */
 	syslog ( LOG_NOTICE, "Executing \"%s\"\n", image->name );
 
@@ -317,6 +322,11 @@ int image_exec ( struct image *image ) {
 	if ( replacement )
 		assert ( replacement->flags & IMAGE_REGISTERED );
 
+ err:
+	/* Unregister image if applicable */
+	if ( image->flags & IMAGE_AUTO_UNREGISTER )
+		unregister_image ( image );
+
 	/* Drop temporary reference to the original image */
 	image_put ( image );
 

src/hci/commands/image_cmd.c

@@ -38,19 +38,24 @@ FILE_LICENCE ( GPL2_OR_LATER );
 struct imgsingle_options {
 	/** Image name */
 	const char *name;
+	/** Free image after execution */
+	int autofree;
 };
 
 /** "img{single}" option list */
 static struct option_descriptor imgsingle_opts[] = {
 	OPTION_DESC ( "name", 'n', required_argument,
 		      struct imgsingle_options, name, parse_string ),
+	OPTION_DESC ( "autofree", 'a', no_argument,
+		      struct imgsingle_options, autofree, parse_flag ),
 };
 
 /** "img{single}" command descriptor */
 static struct command_descriptor imgsingle_cmd =
 	COMMAND_DESC ( struct imgsingle_options, imgsingle_opts,
 		       1, MAX_ARGUMENTS,
-		       "[--name <name>] <uri|image> [<arguments>...]" );
+		       "[--name <name>] [--autofree] "
+		       "<uri|image> [<arguments>...]" );
 
 /** An "img{single}" family command descriptor */
 struct imgsingle_descriptor {
@@ -134,6 +139,10 @@ static int imgsingle_exec ( int argc, char **argv,
 		}
 	}
 
+	/* Set the auto-unregister flag, if applicable */
+	if ( opts.autofree )
+		image->flags |= IMAGE_AUTO_UNREGISTER;
+
 	/* Carry out command action, if applicable */
 	if ( desc->action ) {
 		if ( ( rc = desc->action ( image ) ) != 0 ) {
@@ -160,7 +169,7 @@ static int imgsingle_exec ( int argc, char **argv,
 static struct command_descriptor imgfetch_cmd =
 	COMMAND_DESC ( struct imgsingle_options, imgsingle_opts,
 		       1, MAX_ARGUMENTS,
-		       "[--name <name>] <uri> [<arguments>...]" );
+		       "[--name <name>] [--autofree] <uri> [<arguments>...]" );
 
 /** "imgfetch" family command descriptor */
 struct imgsingle_descriptor imgfetch_desc = {
@@ -202,7 +211,7 @@ static int imgselect_exec ( int argc, char **argv ) {
 static struct command_descriptor imgexec_cmd =
 	COMMAND_DESC ( struct imgsingle_options, imgsingle_opts,
 		       0, MAX_ARGUMENTS,
-		       "[--name <name>] [<uri|image> [<arguments>...]]" );
+		       "[--autofree] [<uri|image> [<arguments>...]]" );
 
 /** "imgexec" family command descriptor */
 struct imgsingle_descriptor imgexec_desc = {

src/include/ipxe/image.h

@@ -67,6 +67,9 @@ struct image {
 /** Image is trusted */
 #define IMAGE_TRUSTED 0x0004
 
+/** Image will be automatically unregistered after execution */
+#define IMAGE_AUTO_UNREGISTER 0x0008
+
 /** An executable image type */
 struct image_type {
 	/** Name of this image type */

src/usr/imgmgmt.c

@@ -146,6 +146,8 @@ void imgstat ( struct image *image ) {
 		printf ( " [TRUSTED]" );
 	if ( image->flags & IMAGE_SELECTED )
 		printf ( " [SELECTED]" );
+	if ( image->flags & IMAGE_AUTO_UNREGISTER )
+		printf ( " [AUTOFREE]" );
 	if ( image->cmdline )
 		printf ( " \"%s\"", image->cmdline );
 	printf ( "\n" );