From 496b6b20cbce3fc27228d1d8290089fb7107b8de Mon Sep 17 00:00:00 2001
From: Michael Chang <mchang@suse.com>
Date: Fri, 18 Feb 2022 21:51:16 +0800
Subject: [PATCH 5/5] export environment at start up

If the prep_loadenv module is built into the core image, it will read
the environment block automatically during start up and export all
variables. The will ease integration with those without early scripts to
running the command.

Signed-off-by: Michael Chang <mchang@suse.com>
---
 grub-core/Makefile.core.def       |  2 +
 grub-core/commands/prep_loadenv.c | 77 +++++++++++++++++++++++++++++++
 grub-core/kern/env.c              |  2 +
 grub-core/kern/main.c             |  3 ++
 include/grub/env.h                |  1 +
 5 files changed, 85 insertions(+)

diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def
index 4d529859be..f3140815b8 100644
--- a/grub-core/Makefile.core.def
+++ b/grub-core/Makefile.core.def
@@ -2628,4 +2628,6 @@ module = {
 module = {
   name = prep_loadenv;
   common = commands/prep_loadenv.c;
+  cflags = '$(CFLAGS_POSIX) $(CFLAGS_GNULIB)';
+  cppflags = '$(CPPFLAGS_POSIX) $(CPPFLAGS_GNULIB)';
 };
diff --git a/grub-core/commands/prep_loadenv.c b/grub-core/commands/prep_loadenv.c
index f4bb270a2b..4f40f7e41a 100644
--- a/grub-core/commands/prep_loadenv.c
+++ b/grub-core/commands/prep_loadenv.c
@@ -10,6 +10,7 @@
 #include <grub/extcmd.h>
 #include <grub/i18n.h>
 #include <grub/gpt_partition.h>
+#include <regex.h>
 
 GRUB_MOD_LICENSE ("GPLv3+");
 
@@ -184,6 +185,65 @@ prep_partname (const char *devname, char **prep)
   return err;
 }
 
+static grub_err_t
+boot_disk_prep_partname (char **name)
+{
+  regex_t regex;
+  int ret;
+  grub_size_t s;
+  char *comperr;
+  const char *cmdpath;
+  regmatch_t *matches = NULL;
+  grub_err_t err = GRUB_ERR_NONE;
+
+  *name = NULL;
+
+  cmdpath = grub_env_get ("cmdpath");
+  if (!cmdpath)
+    return GRUB_ERR_NONE;
+
+  ret = regcomp (&regex, "\\(([^,]+)(,?.*)?\\)(.*)", REG_EXTENDED);
+  if (ret)
+    goto fail;
+
+  matches = grub_calloc (regex.re_nsub + 1, sizeof (*matches));
+  if (! matches)
+    goto fail;
+
+  ret = regexec (&regex, cmdpath, regex.re_nsub + 1, matches, 0);
+  if (!ret)
+    {
+      char *devname = devname = match_substr (matches + 1, cmdpath);
+      if (!devname)
+	{
+	  err = grub_error (GRUB_ERR_FILE_NOT_FOUND, "%s contains no disk name", cmdpath);
+	  goto out;
+	}
+
+      err = prep_partname (devname, name);
+ out:
+      grub_free (devname);
+      regfree (&regex);
+      grub_free (matches);
+      return err;
+    }
+
+ fail:
+  grub_free (matches);
+  s = regerror (ret, &regex, 0, 0);
+  comperr = grub_malloc (s);
+  if (!comperr)
+    {
+      regfree (&regex);
+      return grub_errno;
+    }
+  regerror (ret, &regex, comperr, s);
+  err = grub_error (GRUB_ERR_TEST_FAILURE, "%s", comperr);
+  regfree (&regex);
+  grub_free (comperr);
+  return err;
+}
+
 static grub_err_t
 grub_cmd_prep_loadenv (grub_command_t cmd __attribute__ ((unused)),
 		       int argc,
@@ -211,10 +271,27 @@ grub_cmd_prep_loadenv (grub_command_t cmd __attribute__ ((unused)),
   return err;
 }
 
+static void
+early_prep_loadenv (void)
+{
+  grub_err_t err;
+  char *prep;
+
+  err = boot_disk_prep_partname (&prep);
+  if (err == GRUB_ERR_NONE && prep)
+    err = prep_read_envblk (prep);
+  if (err == GRUB_ERR_BAD_FILE_TYPE || err == GRUB_ERR_FILE_NOT_FOUND)
+    grub_error_pop ();
+  if (err != GRUB_ERR_NONE)
+    grub_print_error ();
+  grub_free (prep);
+}
+
 static grub_command_t cmd_prep_load;
 
 GRUB_MOD_INIT(prep_loadenv)
 {
+  early_env_hook = early_prep_loadenv;
   cmd_prep_load =
     grub_register_command("prep_load_env", grub_cmd_prep_loadenv,
 			  "DEVICE",
diff --git a/grub-core/kern/env.c b/grub-core/kern/env.c
index c408626423..ec0d268905 100644
--- a/grub-core/kern/env.c
+++ b/grub-core/kern/env.c
@@ -28,6 +28,8 @@ static struct grub_env_context initial_context;
 /* The current context.  */
 struct grub_env_context *grub_current_context = &initial_context;
 
+void (*early_env_hook) (void) = NULL;
+
 /* Return the hash representation of the string S.  */
 static unsigned int
 grub_env_hashval (const char *s)
diff --git a/grub-core/kern/main.c b/grub-core/kern/main.c
index c7c6d2d0b8..42ea96e39e 100644
--- a/grub-core/kern/main.c
+++ b/grub-core/kern/main.c
@@ -310,6 +310,9 @@ grub_main (void)
 
   grub_boot_time ("Before execution of embedded config.");
 
+  if (early_env_hook != NULL)
+    early_env_hook ();
+
   if (load_config)
     grub_parser_execute (load_config);
 
diff --git a/include/grub/env.h b/include/grub/env.h
index 76f832eb94..636e190a21 100644
--- a/include/grub/env.h
+++ b/include/grub/env.h
@@ -68,5 +68,6 @@ grub_env_extractor_open (int source);
 grub_err_t
 grub_env_extractor_close (int source);
 
+extern void (*EXPORT_VAR (early_env_hook)) (void);
 
 #endif /* ! GRUB_ENV_HEADER */
-- 
2.34.1