dom/ipc/MMPrinter.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "MMPrinter.h"
   8
   9 #include "jsapi.h"
  10 #include "nsJSUtils.h"
  11 #include "Logging.h"
  12 #include "mozilla/Bootstrap.h"
  13 #include "mozilla/dom/ipc/StructuredCloneData.h"
  14 #include "mozilla/dom/ScriptSettings.h"
  15 #include "mozilla/ErrorResult.h"
  16 #include "mozilla/RandomNum.h"
  17 #include "nsFrameMessageManager.h"
  18 #include "prenv.h"
  19
  20 namespace mozilla::dom {
  21
  22 LazyLogModule MMPrinter::sMMLog("MessageManager");
  23
  24 // You can use
  25 // https://gist.github.com/tomrittervg/adb8688426a9a5340da96004e2c8af79 to parse
  26 // the output of the logs into logs more friendly to reading.
  27
  28 /* static */
  29 void MMPrinter::PrintImpl(char const* aLocation, const nsAString& aMsg,
  30                           ClonedMessageData const& aData) {
  31   NS_ConvertUTF16toUTF8 charMsg(aMsg);
  32
  33   /*
  34    * The topic will be skipped if the topic name appears anywhere as a substring
  35    * of the filter.
  36    *
  37    * Example:
  38    *   MOZ_LOG_MESSAGEMANAGER_SKIP="foobar|extension"
  39    *     Will  match the topics 'foobar', 'foo', 'bar', and 'ten' (even though
  40    * you may not have intended to match the latter three) and it will not match
  41    * the topics 'extensionresult' or 'Foo'.
  42    */
  43   char* mmSkipLog = PR_GetEnv("MOZ_LOG_MESSAGEMANAGER_SKIP");
  44
  45   if (mmSkipLog && strstr(mmSkipLog, charMsg.get())) {
  46     return;
  47   }
  48
  49   uint64_t msg_id = RandomUint64OrDie();
  50
  51   MOZ_LOG(MMPrinter::sMMLog, LogLevel::Debug,
  52           ("%" PRIu64 " %s Message: %s in process type: %s", msg_id, aLocation,
  53            charMsg.get(), XRE_GetProcessTypeString()));
  54
  55   if (!MOZ_LOG_TEST(sMMLog, LogLevel::Verbose)) {
  56     return;
  57   }
  58
  59   ErrorResult rv;
  60
  61   AutoJSAPI jsapi;
  62   // We're using this context to deserialize, stringify, and print a message
  63   // manager message here. Since the messages are always sent from and to system
  64   // scopes, we need to do this in a system scope, or attempting to deserialize
  65   // certain privileged objects will fail.
  66   MOZ_ALWAYS_TRUE(jsapi.Init(xpc::PrivilegedJunkScope()));
  67   JSContext* cx = jsapi.cx();
  68
  69   ipc::StructuredCloneData data;
  70   ipc::UnpackClonedMessageData(aData, data);
  71
  72   /* Read original StructuredCloneData. */
  73   JS::Rooted<JS::Value> scdContent(cx);
  74   data.Read(cx, &scdContent, rv);
  75   if (rv.Failed()) {
  76     // In testing, the only reason this would fail was if there was no data in
  77     // the message; so it seems like this is safe-ish.
  78     MOZ_LOG(MMPrinter::sMMLog, LogLevel::Verbose,
  79             ("%" PRIu64 " (No Data)", msg_id));
  80     rv.SuppressException();
  81     return;
  82   }
  83
  84   JS::Rooted<JSString*> unevalObj(cx, JS_ValueToSource(cx, scdContent));
  85   nsAutoJSString srcString;
  86   if (!srcString.init(cx, unevalObj)) return;
  87
  88   MOZ_LOG(MMPrinter::sMMLog, LogLevel::Verbose,
  89           ("%" PRIu64 " %s", msg_id, NS_ConvertUTF16toUTF8(srcString).get()));
  90 }
  91
  92 }  // namespace mozilla::dom