Bug 1642721 - convert security.sandbox.logging.enabled to a StaticPref. r=bobowen

Depends on D78933

Differential Revision: https://phabricator.services.mozilla.com/D78934

browser/app/profile/firefox.js

@@ -1021,12 +1021,6 @@ pref("dom.ipc.shims.enabledWarnings", false);
   // SetSecurityLevelForContentProcess() for what the different settings mean.
   pref("security.sandbox.content.level", 6);
 
-  // This controls the depth of stack trace that is logged when Windows sandbox
-  // logging is turned on.  This is only currently available for the content
-  // process because the only other sandbox (for GMP) has too strict a policy to
-  // allow stack tracing.  This does not require a restart to take effect.
-  pref("security.sandbox.windows.log.stackTraceDepth", 0);
-
   // This controls the strength of the Windows GPU process sandbox.  Changes
   // will require restart.
   // For information on what the level number means, see

modules/libpref/init/StaticPrefList.yaml

@@ -8779,6 +8779,15 @@
     type: RelaxedAtomicBool
     value: true
     mirror: always
+
+  # This controls the depth of stack trace that is logged when Windows sandbox
+  # logging is turned on. This is only currently available for the content
+  # process because the only other sandbox (for GMP) has too strict a policy to
+  # allow stack tracing. This does not require a restart to take effect.
+-   name: security.sandbox.windows.log.stackTraceDepth
+    type: RelaxedAtomicUint32
+    value: 0
+    mirror: always
 #endif
 
 # When comparing schemes, if this pref is set, view-source URIs are reachable

security/sandbox/chromium-shim/sandbox/win/loggingCallbacks.h

@@ -11,6 +11,7 @@
 
 #include "mozilla/Logging.h"
 #include "mozilla/Preferences.h"
+#include "mozilla/StaticPrefs_security.h"
 #include "mozilla/sandboxing/loggingTypes.h"
 #include "nsContentUtils.h"
 
@@ -24,8 +25,6 @@ static LazyLogModule sSandboxTargetLog("SandboxTarget");
 
 namespace sandboxing {
 
-static uint32_t sStackTraceDepth = 0;
-
 // NS_WalkStackCallback to write a formatted stack frame to an ostringstream.
 static void
 StackFrameToOStringStream(uint32_t aFrameNumber, void* aPC, void* aSP,
@@ -54,14 +53,19 @@ Log(const char* aMessageType,
     msgStream << " for : " << aContext;
   }
 
-  if (aShouldLogStackTrace) {
-    if (sStackTraceDepth) {
+#if defined(MOZ_SANDBOX)
+  // We can only log the stack trace on process types where we know that the
+  // sandbox won't prevent it.
+  if (XRE_IsContentProcess() && aShouldLogStackTrace) {
+    auto stackTraceDepth =
+        StaticPrefs::security_sandbox_windows_log_stackTraceDepth();
+    if (stackTraceDepth) {
       msgStream << std::endl << "Stack Trace:";
-      MozStackWalk(StackFrameToOStringStream, aFramesToSkip, sStackTraceDepth,
+      MozStackWalk(StackFrameToOStringStream, aFramesToSkip, stackTraceDepth,
                    &msgStream);
     }
   }
-
+#endif
   std::string msg = msgStream.str();
 #if defined(DEBUG)
   // Use NS_DebugBreak directly as we want child process prefix, but not source
@@ -88,15 +92,6 @@ InitLoggingIfRequired(ProvideLogFunctionCb aProvideLogFunctionCb)
   if (Preferences::GetBool("security.sandbox.logging.enabled") ||
       PR_GetEnv("MOZ_SANDBOX_LOGGING")) {
     aProvideLogFunctionCb(Log);
-
-#if defined(MOZ_SANDBOX)
-    // We can only log the stack trace on process types where we know that the
-    // sandbox won't prevent it.
-    if (XRE_IsContentProcess()) {
-      Preferences::AddUintVarCache(&sStackTraceDepth,
-        "security.sandbox.windows.log.stackTraceDepth");
-    }
-#endif
   }
 }