Add check-value support and check /proc/cmdline for cros_nodebug

host/lib/crossystem.c

 /* Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include <stdio.h>
 #include <string.h>
 
 #include "host_common.h"
 
@@ skipping 455 matching lines @@
   char *t, *saveptr;
 
   /* Try reading firmware type from BINF.3. */
   binf3 = ReadFileInt(ACPI_BINF_PATH ".3");
   if (BINF3_RECOVERY == binf3)
     return 0;  /* Recovery mode never allows debug. */
   else if (BINF3_DEVELOPER == binf3)
     return 1;  /* Developer firmware always allows debug. */
 
   /* Normal new firmware, older ChromeOS firmware, or non-Chrome firmware.
-   * For all these cases, check /proc/cmdline for cros_debug. */
+   * For all these cases, check /proc/cmdline for cros_[no]debug. */
   f = fopen(KERNEL_CMDLINE_PATH, "rt");
   if (f) {
     if (NULL == fgets(buf, sizeof(buf), f))
       *buf = 0;
     fclose(f);
   }
   for (t = strtok_r(buf, " ", &saveptr); t; t=strtok_r(NULL, " ", &saveptr)) {
     if (0 == strcmp(t, "cros_debug"))
       return 1;
+    else if (0 == strcmp(t, "cros_nodebug"))
+      return 0;
   }
 
   /* Normal new firmware or older Chrome OS firmware allows debug if the
    * dev switch is on. */
   if (1 == ReadFileBit(ACPI_CHSW_PATH, CHSW_DEV_BOOT))
     return 1;
 
   /* All other cases disallow debug. */
   return 0;
 }
@@ skipping 149 matching lines @@
 
 
 /* Set a system property string.
  *
  * Returns 0 if success, -1 if error. */
 int VbSetSystemPropertyString(const char* name, const char* value) {
 
   /* TODO: support setting */
   return -1;
 }