Vboot wrapper API - crossystem and header files

Header file changes for wrapper API implementation

Crossystem support for reading recovery reason from VbSharedData, and
explicit support for version 1 VbSharedData structs.

BUG=chromium-os:16970
TEST=make && make runtests; run crossystem on Alex and make sure it still reports recovery_reason in recovery mode.

Change-Id: I15195b899583e425d3c9e8df09842d764528e2cb
Reviewed-on: http://gerrit.chromium.org/gerrit/3203
Reviewed-by: Tom Wai-Hong Tam <waihong@chromium.org>
Reviewed-by: Che-Liang Chiou <clchiou@chromium.org>
Tested-by: Randall Spangler <rspangler@chromium.org>

4 files changed, 41 insertions, 8 deletions

diff --git a/host/arch/x86/lib/crossystem_arch.c b/host/arch/x86/lib/crossystem_arch.c
index 8b320e4b..25867e12 100644
--- a/host/arch/x86/lib/crossystem_arch.c
+++ b/host/arch/x86/lib/crossystem_arch.c
@@ -156,8 +156,7 @@ int VbWriteNvStorage(VbNvContext* vnc) {
  *         deallocating the pointer, this will take care of both the structure
  *         and the buffer. Null in case of error.
  */
-static uint8_t* VbGetBuffer(const char* filename, int* buffer_size)
-{
+static uint8_t* VbGetBuffer(const char* filename, int* buffer_size) {
   FILE* f = NULL;
   char* file_buffer = NULL;
   uint8_t* output_buffer = NULL;
@@ -240,14 +239,24 @@ static uint8_t* VbGetBuffer(const char* filename, int* buffer_size)
 
 
 VbSharedDataHeader* VbSharedDataRead(void) {
-
   VbSharedDataHeader* sh;
   int got_size = 0;
+  int expect_size;
 
   sh = (VbSharedDataHeader*)VbGetBuffer(ACPI_VDAT_PATH, &got_size);
   if (!sh)
     return NULL;
-  if (got_size < sizeof(VbSharedDataHeader)) {
+
+  /* Make sure the size is sufficient for the struct version we got.
+   * Check supported old versions first. */
+  if (1 == sh->struct_version)
+    expect_size = VB_SHARED_DATA_HEADER_SIZE_V1;
+  else {
+    /* There'd better be enough data for the current header size. */
+    expect_size = sizeof(VbSharedDataHeader);
+  }
+
+  if (got_size < expect_size) {
     Free(sh);
     return NULL;
   }
@@ -371,7 +380,18 @@ static const char* VbReadMainFwType(char* dest, int size) {
 
 /* Read the recovery reason.  Returns the reason code or -1 if error. */
 static int VbGetRecoveryReason(void) {
-  int value;
+  VbSharedDataHeader* sh;
+  int value = -1;
+
+  /* Try reading from VbSharedData first */
+  sh = VbSharedDataRead();
+  if (sh) {
+    if (sh->struct_version >= 2)
+      value = sh->recovery_reason;
+    Free(sh);
+    if (-1 != value)
+      return value;
+  }
 
   /* Try reading type from BINF.4 */
   value = ReadFileInt(ACPI_BINF_PATH ".4");
diff --git a/host/include/crossystem_arch.h b/host/include/crossystem_arch.h
index 6d33c65b..fbef9b19 100644
--- a/host/include/crossystem_arch.h
+++ b/host/include/crossystem_arch.h
@@ -58,8 +58,8 @@ int VbWriteNvStorage(VbNvContext* vnc);
  * some data was not returned; callers must handle this; this is not considered
  * an error.
  *
- * Returns the data buffer, which must be freed by the caller, or NULL if
- * error. */
+ * Returns the data buffer, which must be freed by the caller using
+ * free(), or NULL if error. */
 VbSharedDataHeader* VbSharedDataRead(void);
 
 /* Read an architecture-specific system property integer.
diff --git a/host/include/host_common.h b/host/include/host_common.h
index d8a2b092..007c9d91 100644
--- a/host/include/host_common.h
+++ b/host/include/host_common.h
@@ -8,12 +8,17 @@
 #ifndef VBOOT_REFERENCE_HOST_COMMON_H_
 #define VBOOT_REFERENCE_HOST_COMMON_H_
 
+/* Host is allowed direct use of stdlib funcs such as malloc() and free(),
+ * since it's using the stub implementation from firmware/lib/stub. */
+#define _STUB_IMPLEMENTATION_
+
 #include "cryptolib.h"
 #include "host_key.h"
 #include "host_keyblock.h"
 #include "host_misc.h"
 #include "host_signature.h"
 #include "utility.h"
+#include "vboot_api.h"
 #include "vboot_struct.h"
 
 
diff --git a/host/lib/crossystem.c b/host/lib/crossystem.c
index 7ad5d805..54d08561 100644
--- a/host/lib/crossystem.c
+++ b/host/lib/crossystem.c
@@ -36,8 +36,9 @@ typedef enum VdatIntField {
   VDAT_INT_FW_VERSION_TPM,           /* Current firmware version in TPM */
   VDAT_INT_KERNEL_VERSION_TPM,       /* Current kernel version in TPM */
   VDAT_INT_TRIED_FIRMWARE_B,         /* Tried firmware B due to fwb_tries */
-  VDAT_INT_KERNEL_KEY_VERIFIED       /* Kernel key verified using
+  VDAT_INT_KERNEL_KEY_VERIFIED,      /* Kernel key verified using
                                       * signature, not just hash */
+  VDAT_INT_RECOVERY_REASON           /* Recovery reason for current boot */
 } VdatIntField;
 
 
@@ -325,6 +326,11 @@ int GetVdatInt(VdatIntField field) {
     case VDAT_INT_KERNEL_KEY_VERIFIED:
       value = (sh->flags & VBSD_KERNEL_KEY_VERIFIED ? 1 : 0);
       break;
+    case VDAT_INT_RECOVERY_REASON:
+      /* Field added in struct version 2 */
+      if (sh->struct_version >= 2)
+        value = sh->recovery_reason;
+      break;
   }
 
   Free(sh);
@@ -373,6 +379,8 @@ int VbGetSystemPropertyInt(const char* name) {
     value = GetVdatInt(VDAT_INT_KERNEL_VERSION_TPM);
   } else if (!strcasecmp(name,"tried_fwb")) {
     value = GetVdatInt(VDAT_INT_TRIED_FIRMWARE_B);
+  } else if (!strcasecmp(name,"recovery_reason")) {
+    value = GetVdatInt(VDAT_INT_RECOVERY_REASON);
   }
 
   return value;