From 39bb86c661911f06ff40caa842a9babf18f27c8b Mon Sep 17 00:00:00 2001

From: Javier Martinez Canillas <javierm@redhat.com>

Date: Fri, 2 Feb 2018 11:36:29 +0100

Subject: [PATCH] Enable blscfg command for the emu platform

Allow grub-emu to call a blscfg command. This may be useful for platforms

that don't support GRUB, so grub-emu can be used to parse the BLS configs

and kexec a new kernel using that information.

Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>

---

 grub-core/Makefile.core.def |  1 +

 grub-core/commands/blscfg.c | 46 +++++++++++++++++++++++++++++++++++----------

 2 files changed, 37 insertions(+), 10 deletions(-)

diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def

index 0ca0bdad412..420cbf0a024 100644

--- a/grub-core/Makefile.core.def

+++ b/grub-core/Makefile.core.def

@@ -778,6 +778,7 @@ module = {

   common = commands/blscfg.c;

   enable = efi;

   enable = i386_pc;

+  enable = emu;

 };

 module = {

diff --git a/grub-core/commands/blscfg.c b/grub-core/commands/blscfg.c

index 9ab45631465..e5617c3bc6c 100644

--- a/grub-core/commands/blscfg.c

+++ b/grub-core/commands/blscfg.c

@@ -37,7 +37,12 @@ GRUB_MOD_LICENSE ("GPLv3+");

 #include "loadenv.h"

 #define GRUB_BLS_CONFIG_PATH "/loader/entries/"

+#ifdef GRUB_MACHINE_EMU

+#define GRUB_BOOT_DEVICE "/boot"

+#else

 #define GRUB_BOOT_DEVICE "($root)"

+#endif

+

 #ifdef GRUB_MACHINE_EFI

 #define GRUB_LINUX_CMD "linuxefi"

 #define GRUB_INITRD_CMD "initrdefi"

@@ -46,6 +51,13 @@ GRUB_MOD_LICENSE ("GPLv3+");

 #define GRUB_INITRD_CMD "initrd"

 #endif

+enum

+  {

+    PLATFORM_EFI,

+    PLATFORM_EMU,

+    PLATFORM_BIOS,

+  };

+

 #define grub_free(x) ({grub_dprintf("blscfg", "%s freeing %p\n", __func__, x); grub_free(x); })

 struct keyval

@@ -641,7 +653,7 @@ finish:

 struct find_entry_info {

 	grub_device_t dev;

 	grub_fs_t fs;

-	int efi;

+	int platform;

 };

 /*

@@ -668,13 +680,16 @@ static int find_entry (const char *filename,

       !grub_strcmp (filename, ".."))

     return 0;

-  if (info->efi && !grub_strcasecmp (filename, "boot"))

+  if (info->platform == PLATFORM_EFI && !grub_strcasecmp (filename, "boot"))

     return 0;

   saved_env_buf = grub_malloc (512);

   // set a default blsdir

-  if (info->efi)

+  if (info->platform == PLATFORM_EMU)

+    default_blsdir = grub_xasprintf ("%s%s", GRUB_BOOT_DEVICE,

+				     GRUB_BLS_CONFIG_PATH);

+  else if (info->platform == PLATFORM_EFI)

     default_blsdir = grub_xasprintf ("/EFI/%s%s", filename,

 				     GRUB_BLS_CONFIG_PATH);

   else

@@ -686,7 +701,7 @@ static int find_entry (const char *filename,

   /*

    * try to load a grubenv from /EFI/wherever/grubenv

    */

-  if (info->efi)

+  if (info->platform == PLATFORM_EFI)

     grubenv_path = grub_xasprintf ("(%s)/EFI/%s/grubenv", devid, filename);

   else

     grubenv_path = grub_xasprintf ("(%s)/grub2/grubenv", devid);

@@ -740,7 +755,7 @@ static int find_entry (const char *filename,

     goto finish;

   grub_dprintf ("blscfg", "blsdir: \"%s\"\n", blsdir);

-  if (blsdir[0] != '/' && info->efi)

+  if (blsdir[0] != '/' && info->platform == PLATFORM_EFI)

     blsdir = grub_xasprintf ("/EFI/%s/%s/", filename, blsdir);

   else

     blsdir = grub_strdup (blsdir);

@@ -818,15 +833,21 @@ grub_cmd_blscfg (grub_extcmd_context_t ctxt UNUSED,

     {

       .dev = NULL,

       .fs = NULL,

-      .efi = 0,

+      .platform = PLATFORM_BIOS,

     };

   grub_dprintf ("blscfg", "finding boot\n");

+

+#ifdef GRUB_MACHINE_EMU

+  devid = "host";

+  grub_env_set ("boot", devid);

+#else

   devid = grub_env_get ("boot");

   if (!devid)

     return grub_error (GRUB_ERR_FILE_NOT_FOUND,

 		       N_("variable `%s' isn't set"), "boot");

+#endif

   grub_dprintf ("blscfg", "opening %s\n", devid);

   dev = grub_device_open (devid);

@@ -844,11 +865,16 @@ grub_cmd_blscfg (grub_extcmd_context_t ctxt UNUSED,

   info.dev = dev;

   info.fs = fs;

 #ifdef GRUB_MACHINE_EFI

-  info.efi = 1;

+  info.platform = PLATFORM_EFI;

   grub_dprintf ("blscfg", "scanning /EFI/\n");

   r = fs->dir (dev, "/EFI/", find_entry, &info;;

+#elif GRUB_MACHINE_EMU

+  info.platform = PLATFORM_EMU;

+  grub_dprintf ("blscfg", "scanning %s%s\n", GRUB_BOOT_DEVICE,

+		GRUB_BLS_CONFIG_PATH);

+  r = fs->dir (dev, "/boot/loader/",

+	       find_entry, &info;;

 #else

-  info.efi = 0;

   grub_dprintf ("blscfg", "scanning %s\n", GRUB_BLS_CONFIG_PATH);

   r = fs->dir (dev, "/", find_entry, &info;;

 #endif

@@ -862,7 +888,7 @@ finish:

 static grub_extcmd_t cmd;

-GRUB_MOD_INIT(bls)

+GRUB_MOD_INIT(blscfg)

 {

   grub_dprintf("blscfg", "%s got here\n", __func__);

   cmd = grub_register_extcmd ("blscfg",

@@ -873,7 +899,7 @@ GRUB_MOD_INIT(bls)

 			      NULL);

 }

-GRUB_MOD_FINI(bls)

+GRUB_MOD_FINI(blscfg)

 {

   grub_unregister_extcmd (cmd);

 }