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Blame SOURCES/0209-blscfg-Expand-the-BLS-options-field-instead-of-showi.patch

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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Javier Martinez Canillas <javierm@redhat.com>
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Date: Wed, 18 Jul 2018 08:08:02 +0200
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Subject: [PATCH] blscfg: Expand the BLS options field instead of showing its
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 variables
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The values of the BLS fragment fields can either be string literals or
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grub2 environment variables, the latter will be expanded by grub2 when
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the boot entry is selected.
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But from a usability point of view, is much more convenient if the BLS
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parse code expand any variables that are present in the options field.
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That will allow users to select an entry in the menu by pressing the e
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key and edit the kernel command line parameters. So for example instead
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of showing the following:
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kernel /boot/vmlinuz-4.17.0 $kernelopts
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It would show something like the following:
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kernel /boot/vmlinuz-4.17.0 root=UUID=cec677c9-c890-4103-b94a-bcc191642935
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Suggested-by: Hans de Goede <hdegoede@redhat.com>
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Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
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---
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 grub-core/commands/blscfg.c | 69 ++++++++++++++++++++++++++++++++++++++++++++-
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 1 file changed, 68 insertions(+), 1 deletion(-)
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diff --git a/grub-core/commands/blscfg.c b/grub-core/commands/blscfg.c
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index c6addc4dc12..80d8814fc3f 100644
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--- a/grub-core/commands/blscfg.c
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+++ b/grub-core/commands/blscfg.c
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@@ -32,6 +32,8 @@
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 #include <grub/normal.h>
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 #include <grub/lib/envblk.h>
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+#include <stdbool.h>
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+
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 GRUB_MOD_LICENSE ("GPLv3+");
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 #include "loadenv.h"
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@@ -506,6 +508,70 @@ static char **bls_make_list (struct bls_entry *entry, const char *key, int *num)
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   return list;
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 }
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+static char *field_append(bool is_var, char *buffer, char *start, char *end)
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+{
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+  char *temp = grub_strndup(start, end - start + 1);
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+  const char *field = temp;
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+
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+  if (is_var) {
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+    field = grub_env_get (temp);
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+    if (!field)
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+      return buffer;
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+  }
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+
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+  if (!buffer) {
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+    buffer = grub_strdup(field);
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+    if (!buffer)
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+      return NULL;
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+  } else {
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+    buffer = grub_realloc (buffer, grub_strlen(buffer) + grub_strlen(field));
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+    if (!buffer)
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+      return NULL;
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+
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+    grub_stpcpy (buffer + grub_strlen(buffer), field);
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+  }
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+
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+  return buffer;
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+}
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+
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+static char *expand_val(char *value)
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+{
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+  char *buffer = NULL;
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+  char *start = value;
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+  char *end = value;
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+  bool is_var = false;
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+
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+  while (*value) {
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+    if (*value == '$') {
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+      if (start != end) {
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+	buffer = field_append(is_var, buffer, start, end);
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+	if (!buffer)
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+	  return NULL;
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+      }
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+
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+      is_var = true;
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+      start = value + 1;
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+    } else if (is_var) {
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+      if (!grub_isalnum(*value) && *value != '_') {
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+	buffer = field_append(is_var, buffer, start, end);
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+	is_var = false;
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+	start = value;
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+      }
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+    }
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+
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+    end = value;
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+    value++;
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+  }
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+
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+  if (start != end) {
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+    buffer = field_append(is_var, buffer, start, end);
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+    if (!buffer)
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+      return NULL;
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+  }
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+
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+  return buffer;
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+}
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+
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 static void create_entry (struct bls_entry *entry)
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 {
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   int argc = 0;
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@@ -536,7 +602,7 @@ static void create_entry (struct bls_entry *entry)
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     }
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   title = bls_get_val (entry, "title", NULL);
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-  options = bls_get_val (entry, "options", NULL);
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+  options = expand_val (bls_get_val (entry, "options", NULL));
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   initrds = bls_make_list (entry, "initrd", NULL);
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   hotkey = bls_get_val (entry, "grub_hotkey", NULL);
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@@ -594,6 +660,7 @@ static void create_entry (struct bls_entry *entry)
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 finish:
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   grub_free (initrd);
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   grub_free (initrds);
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+  grub_free (options);
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   grub_free (classes);
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   grub_free (args);
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   grub_free (argv);