* grub-core/Makefile.core.def (pxechain): New module.

* grub-core/loader/i386/pc/pxechainloader.c: New file.
	* grub-core/net/drivers/i386/pc/pxe.c (grub_pxe_get_cached): New
	function.
	(grub_pc_net_config_real): Use grub_pxe_get_cached.
	* include/grub/i386/pc/pxe.h (grub_pxe_get_cached): New proto.

ChangeLog

@@ -1,3 +1,12 @@
+2012-02-05  Vladimir Serbinenko  <phcoder@gmail.com>
+
+	* grub-core/Makefile.core.def (pxechain): New module.
+	* grub-core/loader/i386/pc/pxechainloader.c: New file.
+	* grub-core/net/drivers/i386/pc/pxe.c (grub_pxe_get_cached): New
+	function.
+	(grub_pc_net_config_real): Use grub_pxe_get_cached.
+	* include/grub/i386/pc/pxe.h (grub_pxe_get_cached): New proto.
+
 2012-02-05  Vladimir Serbinenko  <phcoder@gmail.com>
 
 	* grub-core/kern/err.c (GRUB_MAX_ERRMSG): Move to ...

grub-core/Makefile.core.def

@@ -1331,6 +1331,12 @@ module = {
   enable = i386_pc;
 };
 
+module = {
+  name = pxechain;
+  i386_pc = loader/i386/pc/pxechainloader.c;
+  enable = i386_pc;
+};
+
 module = {
   name = multiboot2;
   cppflags = "-DGRUB_USE_MULTIBOOT2";

grub-core/loader/i386/pc/pxechainloader.c

@@ -0,0 +1,167 @@
+/* chainloader.c - boot another boot loader */
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2002,2004,2007,2009,2010,2012  Free Software Foundation, Inc.
+ *
+ *  GRUB 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 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  GRUB 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 GRUB.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <grub/loader.h>
+#include <grub/file.h>
+#include <grub/err.h>
+#include <grub/device.h>
+#include <grub/disk.h>
+#include <grub/misc.h>
+#include <grub/types.h>
+#include <grub/partition.h>
+#include <grub/dl.h>
+#include <grub/command.h>
+#include <grub/machine/biosnum.h>
+#include <grub/i18n.h>
+#include <grub/video.h>
+#include <grub/mm.h>
+#include <grub/cpu/relocator.h>
+#include <grub/machine/pxe.h>
+#include <grub/net.h>
+
+static grub_dl_t my_mod;
+static struct grub_relocator *rel;
+static grub_uint32_t edx = 0xffffffff;
+static char boot_file[128];
+static char server_name[64];
+
+GRUB_MOD_LICENSE ("GPLv3+");
+
+static grub_err_t
+grub_pxechain_boot (void)
+{
+  struct grub_relocator16_state state = { 
+    .cs = 0,
+    .ip = 0x7c00,
+    .ds = 0,
+    .es = 0,
+    .fs = 0,
+    .gs = 0,
+    .ss = 0,
+    .sp = 0x7c00,
+    .edx = edx
+  };
+  struct grub_net_bootp_packet *bp;
+
+  bp = grub_pxe_get_cached (GRUB_PXENV_PACKET_TYPE_DHCP_ACK);
+
+  grub_video_set_mode ("text", 0, 0);
+
+  if (bp && boot_file[0])
+    grub_memcpy (bp->boot_file, boot_file, sizeof (bp->boot_file));
+  if (bp && server_name[0])
+    grub_memcpy (bp->server_name, server_name, sizeof (bp->server_name));
+
+  return grub_relocator16_boot (rel, state);
+}
+
+static grub_err_t
+grub_pxechain_unload (void)
+{
+  grub_relocator_unload (rel);
+  rel = NULL;
+  grub_dl_unref (my_mod);
+  return GRUB_ERR_NONE;
+}
+
+static grub_err_t
+grub_cmd_pxechain (grub_command_t cmd __attribute__ ((unused)),
+		int argc, char *argv[])
+{
+  grub_file_t file = 0;
+  grub_err_t err;
+  void *image;
+  grub_size_t imagesize;
+  char *fname;
+
+  if (argc == 0)
+    return grub_error (GRUB_ERR_BAD_ARGUMENT, "no file specified");
+
+  grub_dl_ref (my_mod);
+
+  rel = grub_relocator_new ();
+  if (!rel)
+    goto fail;
+
+  file = grub_file_open (argv[0]);
+  if (! file)
+    goto fail;
+
+  if (file->device->net && file->device->net->name)
+    fname = file->device->net->name;
+  else
+    {
+      fname = argv[0];
+      if (fname[0] == '(')
+	{
+	  fname = grub_strchr (fname, ')');
+	  if (fname)
+	    fname++;
+	  else
+	    fname = argv[0];
+	}
+    }
+
+  grub_memset (boot_file, 0, sizeof (boot_file));
+  grub_strncpy (boot_file, fname, sizeof (boot_file));
+
+  grub_memset (server_name, 0, sizeof (server_name));
+  if (file->device->net && file->device->net->server)
+    grub_strncpy (server_name, file->device->net->server, sizeof (server_name));
+
+  edx = grub_get_root_biosnumber ();
+
+  imagesize = grub_file_size (file);
+  {
+    grub_relocator_chunk_t ch;
+    err = grub_relocator_alloc_chunk_addr (rel, &ch, 0x7c00, imagesize);
+    if (err)
+      goto fail;
+    image = get_virtual_current_address (ch);
+  }
+
+  if (grub_file_read (file, image, imagesize) != (grub_ssize_t) imagesize)
+    goto fail;
+ 
+  grub_loader_set (grub_pxechain_boot, grub_pxechain_unload, 1);
+  return GRUB_ERR_NONE;
+
+ fail:
+
+  if (file)
+    grub_file_close (file);
+
+  grub_pxechain_unload ();
+
+  return grub_errno;
+}
+
+static grub_command_t cmd;
+
+GRUB_MOD_INIT(pxechainloader)
+{
+  cmd = grub_register_command ("pxechainloader", grub_cmd_pxechain,
+			       0, N_("Load a PXE image."));
+  my_mod = mod;
+}
+
+GRUB_MOD_FINI(pxechainloader)
+{
+  grub_unregister_command (cmd);
+}

grub-core/net/drivers/i386/pc/pxe.c

@@ -311,20 +311,29 @@ struct grub_net_card grub_pxe_card =
   .name = "pxe"
 };
 
-static void
-grub_pc_net_config_real (char **device, char **path)
+void *
+grub_pxe_get_cached (grub_uint16_t type)
 {
-  struct grub_net_bootp_packet *bp;
   struct grub_pxenv_get_cached_info ci;
-  ci.packet_type = GRUB_PXENV_PACKET_TYPE_DHCP_ACK;
+  ci.packet_type = type;
   ci.buffer = 0;
   ci.buffer_size = 0;
   grub_pxe_call (GRUB_PXENV_GET_CACHED_INFO, &ci, pxe_rm_entry);
   if (ci.status)
+    return 0;
+
+  return LINEAR (ci.buffer);
+}
+
+static void
+grub_pc_net_config_real (char **device, char **path)
+{
+  struct grub_net_bootp_packet *bp;
+
+  bp = grub_pxe_get_cached (GRUB_PXENV_PACKET_TYPE_DHCP_ACK);
+
+  if (!bp)
     return;
-
-  bp = LINEAR (ci.buffer);
-
   grub_net_configure_by_dhcp_ack ("pxe", &grub_pxe_card, 0,
 				  bp, GRUB_PXE_BOOTP_SIZE,
 				  1, device, path);

include/grub/i386/pc/pxe.h

@@ -284,6 +284,9 @@ int EXPORT_FUNC(grub_pxe_call) (int func, void * data, grub_uint32_t pxe_rm_entr
 
 extern struct grub_pxe_bangpxe *grub_pxe_pxenv;
 
+void *
+grub_pxe_get_cached (grub_uint16_t type);
+
 #endif
 
 #endif /* GRUB_CPU_PXE_H */