[PATCH] hexdump: Add parameter to save output to variable

[Carlo Caione]

From: Carlo Caione <ca...@endlessm.com>

In endless we are using hexdump to read into the hiberfil.sys windows
file to detect if windows is hybernated or not.

With this patch we introduce a new parameter to hexdump to enable the
possibility to save the output to a variable.

Signed-off-by: Carlo Caione <ca...@endlessm.com>
---
 grub-core/commands/hexdump.c | 42 ++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 40 insertions(+), 2 deletions(-)

diff --git a/grub-core/commands/hexdump.c b/grub-core/commands/hexdump.c
index 4c884b3a1..e6517ad57 100644
--- a/grub-core/commands/hexdump.c
+++ b/grub-core/commands/hexdump.c
@@ -24,6 +24,7 @@
 #include <grub/lib/hexdump.h>
 #include <grub/extcmd.h>
 #include <grub/i18n.h>
+#include <grub/env.h>
 
 GRUB_MOD_LICENSE ("GPLv3+");
 
@@ -31,6 +32,8 @@ static const struct grub_arg_option options[] = {
   {"skip", 's', 0, N_("Skip offset bytes from the beginning of file."), 0,
    ARG_TYPE_INT},
   {"length", 'n', 0, N_("Read only LENGTH bytes."), 0, ARG_TYPE_INT},
+  {"set", 't', 0, N_("Set a variable to return value."), N_("VARNAME"),
+   ARG_TYPE_STRING},
   {0, 0, 0, 0, 0, 0}
 };
 
@@ -42,6 +45,8 @@ grub_cmd_hexdump (grub_extcmd_context_t ctxt, int argc, char 
**args)
   grub_ssize_t size, length;
   grub_disk_addr_t skip;
   int namelen;
+  char *var_buf = NULL;
+  char *var_p = NULL;
 
   if (argc != 1)
     return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("filename expected"));
@@ -50,6 +55,14 @@ grub_cmd_hexdump (grub_extcmd_context_t ctxt, int argc, char 
**args)
   skip = (state[0].set) ? grub_strtoull (state[0].arg, 0, 0) : 0;
   length = (state[1].set) ? grub_strtoul (state[1].arg, 0, 0) : 256;
 
+  if (state[2].set)
+    {
+      var_buf = grub_malloc (length + 1);
+      if (! var_buf)
+        return grub_errno;
+      var_p = var_buf;
+    }
+
   if (!grub_strcmp (args[0], "(mem)"))
     hexdump (skip, (char *) (grub_addr_t) skip, length);
   else if ((args[0][0] == '(') && (args[0][namelen - 1] == ')'))
@@ -76,7 +89,13 @@ grub_cmd_hexdump (grub_extcmd_context_t ctxt, int argc, char 
**args)
           if (grub_disk_read (disk, sector, ofs, len, buf))
             break;
 
-          hexdump (skip, buf, len);
+          if (state[2].set)
+            {
+              grub_memcpy (var_p, buf, len);
+              var_p += len;
+            }
+          else
+            hexdump (skip, buf, len);
 
           ofs = 0;
           skip += len;
@@ -101,7 +120,15 @@ grub_cmd_hexdump (grub_extcmd_context_t ctxt, int argc, 
char **args)
          unsigned long len;
 
          len = ((length) && (size > length)) ? length : size;
-         hexdump (skip, buf, len);
+
+          if (state[2].set)
+            {
+              grub_memcpy (var_p, buf, len);
+              var_p += len;
+            }
+          else
+            hexdump (skip, buf, len);
+
          skip += len;
          if (length)
            {
@@ -114,6 +141,17 @@ grub_cmd_hexdump (grub_extcmd_context_t ctxt, int argc, 
char **args)
       grub_file_close (file);
     }
 
+  if (state[2].set)
+    {
+      grub_ssize_t i;
+
+      *var_p = 0;
+      for (i = 0; i < length - 1; i++)
+        var_buf[i] = ((var_buf[i] >= 32) && (var_buf[i] < 127)) ? var_buf[i] : 
'.';
+
+      grub_env_set(state[2].arg, var_buf);
+    }
+
   return 0;
 }
 
-- 
2.14.1


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