Add a "debug_build" query to crossystem.

Querying "debug_build" allows the caller to determine whether the
image has requested debug, independent of the setting of the
dev_mode switch.

BUG=chromium:308678
BRANCH=none
TEST=use the new command option on both base and dev images

Change-Id: I369f26d75156f2e88d9f6f467efbf8f633e78bda
Reviewed-on: https://chromium-review.googlesource.com/174107
Reviewed-by: Bill Richardson <wfrichar@chromium.org>
Tested-by: Richard Barnette <jrbarnette@chromium.org>
Reviewed-by: Will Drewry <wad@chromium.org>
Commit-Queue: Richard Barnette <jrbarnette@chromium.org>

2 files changed, 40 insertions, 8 deletions

diff --git a/host/lib/crossystem.c b/host/lib/crossystem.c
index 2ef222b0..b4824332 100644
--- a/host/lib/crossystem.c
+++ b/host/lib/crossystem.c
@@ -50,6 +50,15 @@ typedef enum VdatIntField {
 } VdatIntField;
 
 
+/* Description of build options that may be specified on the
+ * kernel command line. */
+typedef enum VbBuildOption {
+  VB_BUILD_OPTION_UNKNOWN,
+  VB_BUILD_OPTION_DEBUG,
+  VB_BUILD_OPTION_NODEBUG
+} VbBuildOption;
+
+
 /* Masks for kern_nv usage by kernel. */
 #define KERN_NV_FWUPDATE_TRIES_MASK 0x0000000F
 /* If you want to use the remaining currently-unused bits in kern_nv
@@ -122,17 +131,14 @@ VbSetNvCleanup:
   return retval;
 }
 
-
-/* Determine whether OS-level debugging should be allowed.  Passed the
- * destination and its size.  Returns 1 if yes, 0 if no, -1 if error. */
-int VbGetCrosDebug(void) {
+/* Find what build/debug status is specified on the kernel command
+ * line, if any. */
+static VbBuildOption VbScanBuildOption(void) {
   FILE* f = NULL;
   char buf[4096] = "";
   char *t, *saveptr;
   const char *delimiters = " \r\n";
 
-  /* If the currently running system specifies its debug status, use
-   * that in preference to other indicators. */
   f = fopen(KERNEL_CMDLINE_PATH, "r");
   if (NULL != f) {
     if (NULL == fgets(buf, sizeof(buf), f))
@@ -142,8 +148,31 @@ int VbGetCrosDebug(void) {
   for (t = strtok_r(buf, delimiters, &saveptr); t;
        t = strtok_r(NULL, delimiters, &saveptr)) {
     if (0 == strcmp(t, "cros_debug"))
-      return 1;
+      return VB_BUILD_OPTION_DEBUG;
     else if (0 == strcmp(t, "cros_nodebug"))
+      return VB_BUILD_OPTION_NODEBUG;
+  }
+
+  return VB_BUILD_OPTION_UNKNOWN;
+}
+
+
+/* Determine whether the running OS image was built for debugging.
+ * Returns 1 if yes, 0 if no or indeterminate. */
+int VbGetDebugBuild(void) {
+  return VB_BUILD_OPTION_DEBUG == VbScanBuildOption();
+}
+
+
+/* Determine whether OS-level debugging should be allowed.
+ * Returns 1 if yes, 0 if no or indeterminate. */
+int VbGetCrosDebug(void) {
+  /* If the currently running system specifies its debug status, use
+   * that in preference to other indicators. */
+  VbBuildOption option = VbScanBuildOption();
+  if (VB_BUILD_OPTION_DEBUG == option) {
+      return 1;
+  } else if (VB_BUILD_OPTION_NODEBUG == option) {
       return 0;
   }
 
@@ -435,6 +464,8 @@ int VbGetSystemPropertyInt(const char* name) {
   /* Other parameters */
   else if (!strcasecmp(name,"cros_debug")) {
     value = VbGetCrosDebug();
+  } else if (!strcasecmp(name,"debug_build")) {
+    value = VbGetDebugBuild();
   } else if (!strcasecmp(name,"devsw_boot")) {
     value = GetVdatInt(VDAT_INT_DEVSW_BOOT);
   } else if (!strcasecmp(name,"devsw_virtual")) {
diff --git a/utility/crossystem.c b/utility/crossystem.c
index 91465002..d7007eeb 100644
--- a/utility/crossystem.c
+++ b/utility/crossystem.c
@@ -40,7 +40,7 @@ const Param sys_param_list[] = {
   {"cros_debug", 0, "OS should allow debug features"},
   {"dbg_reset", CAN_WRITE, "Debug reset mode request (writable)"},
   {"ddr_type", IS_STRING, "Type of DDR RAM"},
-  {"disable_dev_request", CAN_WRITE, "Disable virtual dev-mode on next boot"},
+  {"debug_build", 0, "OS image built for debug features"},
   {"dev_boot_usb", CAN_WRITE,
    "Enable developer mode boot from USB/SD (writable)"},
   {"dev_boot_legacy", CAN_WRITE,
@@ -49,6 +49,7 @@ const Param sys_param_list[] = {
    "Enable developer mode boot only from official kernels (writable)"},
   {"devsw_boot", 0, "Developer switch position at boot"},
   {"devsw_cur",  0, "Developer switch current position"},
+  {"disable_dev_request", CAN_WRITE, "Disable virtual dev-mode on next boot"},
   {"ecfw_act", IS_STRING, "Active EC firmware"},
   {"fmap_base", 0, "Main firmware flashmap physical address", "0x%08x"},
   {"fwb_tries", CAN_WRITE, "Try firmware B count (writable)"},