From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001

From: Hans de Goede <hdegoede@redhat.com>

Date: Mon, 4 Jun 2018 19:49:47 +0200

Subject: [PATCH] grub-editenv: Add "incr" command to increment integer value

 env. variables

To be able to automatically detect if the last boot was successful,

We want to keep count of succesful / failed boots in some integer

environment variable.

This commit adds a grub-editenvt "incr" command to increment such

integer value env. variables by 1 for use from various boot scripts.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>

---

 util/grub-editenv.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++

 1 file changed, 50 insertions(+)

diff --git a/util/grub-editenv.c b/util/grub-editenv.c

index db6f187cc63..948eec8a114 100644

--- a/util/grub-editenv.c

+++ b/util/grub-editenv.c

@@ -53,6 +53,9 @@ static struct argp_option options[] = {

   /* TRANSLATORS: "unset" is a keyword. It's a summary of "unset" subcommand.  */

   {N_("unset [NAME ...]"),    0, 0, OPTION_DOC|OPTION_NO_USAGE,

    N_("Delete variables."), 0},

+  /* TRANSLATORS: "incr" is a keyword. It's a summary of "incr" subcommand.  */

+  {N_("incr [NAME ...]"),     0, 0, OPTION_DOC|OPTION_NO_USAGE,

+   N_("Increase value of integer variables."), 0},

   {0,         0, 0, OPTION_DOC, N_("Options:"), -1},

   {"verbose", 'v', 0, 0, N_("print verbose messages."), 0},

@@ -253,6 +256,51 @@ unset_variables (const char *name, int argc, char *argv[])

   grub_envblk_close (envblk);

 }

+struct get_int_value_params {

+  char *varname;

+  int value;

+};

+

+static int

+get_int_value (const char *varname, const char *value, void *hook_data)

+{

+  struct get_int_value_params *params = hook_data;

+

+  if (strcmp (varname, params->varname) == 0) {

+    params->value = strtol (value, NULL, 10);

+    return 1;

+  }

+  return 0;

+}

+

+static void

+incr_variables (const char *name, int argc, char *argv[])

+{

+  grub_envblk_t envblk;

+  char buf[16];

+

+  envblk = open_envblk_file (name);

+  while (argc)

+    {

+      struct get_int_value_params params = {

+        .varname = argv[0],

+        .value = 0, /* Consider unset variables 0 */

+      };

+

+      grub_envblk_iterate (envblk, &params, get_int_value);

+      snprintf(buf, sizeof(buf), "%d", params.value + 1);

+

+      if (! grub_envblk_set (envblk, argv[0], buf))

+        grub_util_error ("%s", _("environment block too small"));

+

+      argc--;

+      argv++;

+    }

+

+  write_envblk (name, envblk);

+  grub_envblk_close (envblk);

+}

+

 int

 main (int argc, char *argv[])

 {

@@ -292,6 +340,8 @@ main (int argc, char *argv[])

     set_variables (filename, argc - curindex, argv + curindex);

   else if (strcmp (command, "unset") == 0)

     unset_variables (filename, argc - curindex, argv + curindex);

+  else if (strcmp (command, "incr") == 0)

+    incr_variables (filename, argc - curindex, argv + curindex);

   else

     {

       char *program = xstrdup(program_name);