svn commit: r343911 - head/stand/efi/libefi

[Marcin Wojtas]

Author: mw
Date: Fri Feb  8 14:56:28 2019
New Revision: 343911
URL: https://svnweb.freebsd.org/changeset/base/343911

Log:
  Allow reading the UEFI variable size
  
  When loading bigger variables form UEFI it is necessary to know their
  size beforehand, so that an appropriate amount of memory can be
  allocated. The easiest way to do this is to try to read the variable
  with buffer size equal 0, expecting EFI_BUFFER_TOO_SMALL error to be
  returned. Allow such possible approach in efi_getenv routine.
  
  Extracted from a bigger patch as suggested by imp.
  
  Submitted by: Kornel Duleba <mindal at semihalf.com>
  Obtained from: Semihalf
  Sponsored by: Stormshield

Modified:
  head/stand/efi/libefi/efienv.c

Modified: head/stand/efi/libefi/efienv.c
==============================================================================
--- head/stand/efi/libefi/efienv.c	Fri Feb  8 14:32:27 2019	(r343910)
+++ head/stand/efi/libefi/efienv.c	Fri Feb  8 14:56:28 2019	(r343911)
@@ -48,7 +48,7 @@ efi_getenv(EFI_GUID *g, const char *v, void *data, siz
 		return (EFI_OUT_OF_RESOURCES);
 	dl = *len;
 	rv = RS->GetVariable(uv, g, &attr, &dl, data);
-	if (rv == EFI_SUCCESS)
+	if (rv == EFI_SUCCESS || rv == EFI_BUFFER_TOO_SMALL)
 		*len = dl;
 	free(uv);
 	return (rv);