[image] Allow multiple embedded images

This patch extends the embedded image feature to allow multiple
embedded images instead of just one.

gPXE now always boots the first embedded image on startup instead of
doing the hardcoded DHCP boot (aka autoboot).

Based heavily upon a patch by Stefan Hajnoczi <stefanha@gmail.com>.

contrib/scripts/gpxelinux.gpxe

+#!gpxe
+dhcp net0
+imgload img1
+boot img1

contrib/scripts/static.gpxe

+#!gpxe
+ifopen net0
+set net0/ip 10.0.2.15
+set net0/netmask 255.255.255.0
+set net0/gateway 10.0.2.2
+set net0/dns 10.0.2.3
+kernel http://etherboot.org/gtest/gtest.gpxe
+boot gtest.gpxe

src/Makefile.housekeeping

 # Check for various tool workarounds
 #
 
+# Make syntax does not allow use of comma or space in certain places.
+# This ugly workaround is suggested in the manual.
+#
+COMMA	:= ,
+EMPTY	:=
+SPACE	:= $(EMPTY) $(EMPTY)
+
 # Check for an old version of gas (binutils 2.9.1)
 #
 OLDGAS	:= $(shell $(AS) --version | grep -q '2\.9\.1' && $(ECHO) -DGAS291)
 ASFLAGS		+= $(EXTRA_ASFLAGS)
 LDFLAGS		+= $(EXTRA_LDFLAGS)
 
-# Embedded image, if present
+# Embedded image(s), or default if not set
 #
-EMBEDDED_IMAGE	= /dev/null
+EMBEDDED_IMAGE	= image/default.gpxe
 
 # Inhibit -Werror if NO_WERROR is specified on make command line
 #
 roms :
 	@$(ECHO) $(ROMS)
 
-# Embedded binary
-$(BIN)/embedimg.bin: $(EMBEDDED_IMAGE)
-	$(QM)$(ECHO) "  [COPY] $@"
-	$(Q)$(CP) -f $(EMBEDDED_IMAGE) $@
+# List of embedded images included in the last build of embedded.o.
+# This is needed in order to correctly rebuild embedded.o whenever the
+# list of objects changes.
+#
+EMBEDDED_LIST	:= $(BIN)/.embedded.list
+ifeq ($(wildcard $(EMBEDDED_LIST)),)
+EMBEDDED_LIST_IMAGE :=
+else
+EMBEDDED_LIST_IMAGE := $(shell cat $(EMBEDDED_LIST))
+endif
+ifneq ($(EMBEDDED_LIST_IMAGE),$(EMBEDDED_IMAGE))
+$(shell $(ECHO) "$(EMBEDDED_IMAGE)" > $(EMBEDDED_LIST))
+endif
+
+$(EMBEDDED_LIST) :
+
+VERYCLEANUP	+= $(EMBEDDED_LIST)
+
+EMBEDDED_FILES	:= $(subst $(COMMA), ,$(EMBEDDED_IMAGE))
+EMBED_ALL	:= $(foreach i,$(shell seq 1 $(words $(EMBEDDED_FILES))),\
+		     EMBED ( $(i), \"$(word $(i), $(EMBEDDED_FILES))\",\
+			     \"$(notdir $(word $(i),$(EMBEDDED_FILES)))\" ))
 
-$(BIN)/embed.o: $(BIN)/embedimg.bin
-CFLAGS_embed = -DEMBEDIMG=\"$(BIN)/embedimg.bin\"
+$(BIN)/embedded.o : $(EMBEDDED_FILES) $(EMBEDDED_LIST)
+CFLAGS_embedded = -DEMBED_ALL="$(EMBED_ALL)"
 
 # Generate the NIC file from the parsed source files.  The NIC file is
 # only for rom-o-matic.
 # Calculate list of debugging versions of objects to be included in
 # the target.
 #
-COMMA		:= ,
 DEBUG_LIST	= $(subst $(COMMA), ,$(DEBUG))
 DEBUG_OBJ_LEVEL	= $(firstword $(word 2,$(subst :, ,$(1))) 1)
 DEBUG_OBJ_BASE	= $(word 1,$(subst :, ,$(1))).dbg$(call DEBUG_OBJ_LEVEL,$(1))

src/core/config.c

  *
  */
 REQUIRE_OBJECT ( device );
+REQUIRE_OBJECT ( embedded );

src/core/main.c

 #include <gpxe/features.h>
 #include <gpxe/shell.h>
 #include <gpxe/shell_banner.h>
+#include <gpxe/image.h>
 #include <usr/autoboot.h>
 #include <config/general.h>
 
  */
 __asmcall int main ( void ) {
 	struct feature *feature;
+	struct image *image;
 
 	/* Some devices take an unreasonably long time to initialise */
 	printf ( PRODUCT_SHORT_NAME " initialising devices...\n" );
 		/* User wants shell; just give them a shell */
 		shell();
 	} else {
-		/* User doesn't want shell; try booting.  If booting
-		 * fails, offer a second chance to enter the shell for
-		 * diagnostics.
+		/* User doesn't want shell; load and execute the first
+		 * image.  If booting fails (i.e. if the image
+		 * returns, or fails to execute), offer a second
+		 * chance to enter the shell for diagnostics.
 		 */
-		autoboot();
+		for_each_image ( image ) {
+			image_exec ( image );
+			break;
+		}
+
 		if ( shell_banner() )
 			shell();
 	}

src/image/default.gpxe

+#!gpxe
+autoboot

src/image/embed.S

-	.section ".data", "aw", @progbits
-	.balign 4
-	.globl _embedded_image_start
-_embedded_image_start:
-	.incbin EMBEDIMG
-	.globl _embedded_image_end
-_embedded_image_end:

src/image/embedded.c

 /** @file
  *
- * Take a possible embedded image and put it in a struct image
- * data structure.
+ * Embedded image support
+ *
+ * Embedded images are images built into the gPXE binary and do not require
+ * fetching over the network.
  */
 
+#include <string.h>
 #include <gpxe/image.h>
-#include <gpxe/malloc.h>
 #include <gpxe/uaccess.h>
-#include <gpxe/umalloc.h>
-#include <gpxe/embedded.h>
+#include <gpxe/init.h>
 
-extern char _embedded_image_start[], _embedded_image_end[];
+/**
+ * Free embedded image
+ *
+ * @v refcnt		Reference counter
+ */
+static void embedded_image_free ( struct refcnt *refcnt __unused ) {
+	/* Do nothing */
+}
 
-struct image *embedded_image(void)
-{
-	static int reclaimed = 0;
-	struct image *image;
-	size_t eisize = _embedded_image_end - _embedded_image_start;
+/* Raw image data for all embedded images */
+#undef EMBED
+#define EMBED( _index, _path, _name )					\
+	extern char embedded_image_ ## _index ## _data[];		\
+	extern char embedded_image_ ## _index ## _len[];		\
+	__asm__ ( ".section \".rodata\", \"a\", @progbits\n\t"		\
+		  "\nembedded_image_" #_index "_data:\n\t"		\
+		  ".incbin \"" _path "\"\n\t"				\
+		  "\nembedded_image_" #_index "_end:\n\t"		\
+		  ".equ embedded_image_" #_index "_len, "		\
+			"( embedded_image_" #_index "_end - "		\
+			"  embedded_image_" #_index "_data )\n\t"	\
+		  ".previous\n\t" );
+EMBED_ALL
 
-	if ( !eisize )
-		return NULL;	/* No embedded image */
+/* Image structures for all embedded images */
+#undef EMBED
+#define EMBED( _index, _path, _name ) {					\
+	.refcnt = { .free = embedded_image_free, },			\
+	.name = _name,							\
+	.data = ( userptr_t ) ( embedded_image_ ## _index ## _data ),	\
+	.len = ( size_t ) embedded_image_ ## _index ## _len,		\
+},
+static struct image embedded_images[] = {
+	EMBED_ALL
+};
 
-	if ( reclaimed )
-		return NULL;	/* Already reclaimed */
+/**
+ * Register all embedded images
+ */
+static void embedded_init ( void ) {
+	unsigned int i;
+	struct image *image;
+	void *data;
+	int rc;
 
-	DBG ( "Embedded image: %zd bytes at %p\n",
-	      eisize, _embedded_image_start );
+	/* Fix up data pointers and register images */
+	for ( i = 0 ; i < ( sizeof ( embedded_images ) /
+			    sizeof ( embedded_images[0] ) ) ; i++ ) {
+		image = &embedded_images[i];
 
-	image = alloc_image();
-	if (!image)
-		return NULL;
+		/* virt_to_user() cannot be used in a static
+		 * initialiser, so we cast the pointer to a userptr_t
+		 * in the initialiser and fix it up here.  (This will
+		 * actually be a no-op on most platforms.)
+		 */
+		data = ( ( void * ) image->data );
+		image->data = virt_to_user ( data );
 
-	image->len     = eisize;
-	image->data    = umalloc(eisize);
-	if (image->data == UNULL) {
-		image_put(image);
-		return image = NULL;
-	}
-	copy_to_user(image->data, 0, _embedded_image_start, eisize);
-	register_image(image);
+		DBG ( "Embedded image \"%s\": %zd bytes at %p\n",
+		      image->name, image->len, data );
 
-	/* Reclaim embedded image memory */
-	reclaimed = 1;
-	mpopulate(_embedded_image_start, eisize);
+		if ( ( rc = register_image ( image ) ) != 0 ) {
+			DBG ( "Could not register embedded image \"%s\": "
+			      "%s\n", image->name, strerror ( rc ) );
+			return;
+		}
+	}
 
-	return image;
+	/* Load the first image */
+	image = &embedded_images[0];
+	if ( ( rc = image_autoload ( image ) ) != 0 ) {
+		DBG ( "Could not load embedded image \"%s\": %s\n",
+		      image->name, strerror ( rc ) );
+		return;
+	}
 }
 
+/** Embedded image initialisation function */
+struct init_fn embedded_init_fn __init_fn ( INIT_NORMAL ) = {
+	.initialise = embedded_init,
+};

src/include/gpxe/embedded.h

-#ifndef _GPXE_EMBEDDED_H
-#define _GPXE_EMBEDDED_H
-
-#include <gpxe/image.h>
-
-struct image *embedded_image(void);
-
-#endif
-

src/include/gpxe/errfile.h

 #define ERRFILE_script		      ( ERRFILE_IMAGE | 0x00020000 )
 #define ERRFILE_segment		      ( ERRFILE_IMAGE | 0x00030000 )
 #define ERRFILE_efi_image	      ( ERRFILE_IMAGE | 0x00040000 )
+#define ERRFILE_embedded	      ( ERRFILE_IMAGE | 0x00050000 )
 
 #define ERRFILE_asn1		      ( ERRFILE_OTHER | 0x00000000 )
 #define ERRFILE_chap		      ( ERRFILE_OTHER | 0x00010000 )

src/include/gpxe/uri.h

  *
  */
 
+#include <stddef.h>
 #include <stdlib.h>
 #include <gpxe/refcnt.h>
 

src/usr/autoboot.c

 #include <gpxe/dhcp.h>
 #include <gpxe/settings.h>
 #include <gpxe/image.h>
-#include <gpxe/embedded.h>
 #include <gpxe/sanboot.h>
 #include <gpxe/uri.h>
 #include <usr/ifmgmt.h>
 	return NULL;
 }
 
-/**
- * Boot embedded image
- *
- * @ret rc		Return status code
- */
-static int boot_embedded_image ( void ) {
-	struct image *image;
-	int rc;
-
-	image = embedded_image();
-	if ( !image )
-		return ENOENT;
-
-	if ( ( rc = imgload ( image ) ) != 0 ) {
-		printf ( "Could not load embedded image: %s\n",
-			 strerror ( rc ) );
-	} else if ( ( rc = imgexec ( image ) ) != 0 ) {
-		printf ( "Could not boot embedded image: %s\n",
-			 strerror ( rc ) );
-	}
-	image_put ( image );
-	return rc;
-}
-
 /**
  * Boot using next-server and filename
  *
 		return rc;
 	route();
 
-	/* Try to boot an embedded image if we have one */
-	rc = boot_embedded_image ();
-	if ( rc != ENOENT )
-		return rc;
-
 	/* Try PXE menu boot, if applicable */
 	fetch_string_setting ( NULL, &vendor_class_id_setting,
 			       buf, sizeof ( buf ) );