/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */ /* vim:set ts=4 sw=4 sts=4 ci et: */ /* This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ #include #include "mozilla/IOInterposer.h" #include "mozilla/PoisonIOInterposer.h" #include "mozilla/ProcessedStack.h" #include "mozilla/SHA1.h" #include "mozilla/Scoped.h" #include "mozilla/StaticPtr.h" #include "mozilla/Telemetry.h" #include "nsAppDirectoryServiceDefs.h" #include "nsDirectoryServiceUtils.h" #include "nsPrintfCString.h" #include "nsStackWalk.h" #include "plstr.h" #ifdef XP_WIN #define NS_T(str) L ## str #define NS_SLASH "\\" #include #include #include #include #include #include #else #define NS_SLASH "/" #endif #include "LateWriteChecks.h" #if !defined(XP_WIN) || (!defined(MOZ_OPTIMIZE) || defined(MOZ_PROFILING) || defined(DEBUG)) #define OBSERVE_LATE_WRITES #endif using namespace mozilla; /*************************** Auxiliary Declarations ***************************/ // This a wrapper over a file descriptor that provides a Printf method and // computes the sha1 of the data that passes through it. class SHA1Stream { public: explicit SHA1Stream(FILE *stream) : mFile(stream) { MozillaRegisterDebugFILE(mFile); } void Printf(const char *aFormat, ...) { MOZ_ASSERT(mFile); va_list list; va_start(list, aFormat); nsAutoCString str; str.AppendPrintf(aFormat, list); va_end(list); mSHA1.update(str.get(), str.Length()); fwrite(str.get(), 1, str.Length(), mFile); } void Finish(SHA1Sum::Hash &aHash) { int fd = fileno(mFile); fflush(mFile); MozillaUnRegisterDebugFD(fd); fclose(mFile); mSHA1.finish(aHash); mFile = nullptr; } private: FILE *mFile; SHA1Sum mSHA1; }; static void RecordStackWalker(void *aPC, void *aSP, void *aClosure) { std::vector *stack = static_cast*>(aClosure); stack->push_back(reinterpret_cast(aPC)); } /**************************** Late-Write Observer ****************************/ /** * An implementation of IOInterposeObserver to be registered with IOInterposer. * This observer logs all writes as late writes. */ class LateWriteObserver MOZ_FINAL : public IOInterposeObserver { public: LateWriteObserver(const char* aProfileDirectory) : mProfileDirectory(PL_strdup(aProfileDirectory)) { } ~LateWriteObserver() { PL_strfree(mProfileDirectory); mProfileDirectory = nullptr; } void Observe(IOInterposeObserver::Observation& aObservation); private: char* mProfileDirectory; }; void LateWriteObserver::Observe(IOInterposeObserver::Observation& aOb) { #ifdef OBSERVE_LATE_WRITES // Crash if that is the shutdown check mode if (gShutdownChecks == SCM_CRASH) { MOZ_CRASH(); } // If we have shutdown mode SCM_NOTHING or we can't record then abort if (gShutdownChecks == SCM_NOTHING || !Telemetry::CanRecord()) { return; } // Write the stack and loaded libraries to a file. We can get here // concurrently from many writes, so we use multiple temporary files. std::vector rawStack; NS_StackWalk(RecordStackWalker, /* skipFrames */ 0, /* maxFrames */ 0, reinterpret_cast(&rawStack), 0, nullptr); Telemetry::ProcessedStack stack = Telemetry::GetStackAndModules(rawStack); nsPrintfCString nameAux("%s%s%s", mProfileDirectory, NS_SLASH, "Telemetry.LateWriteTmpXXXXXX"); char *name; nameAux.GetMutableData(&name); // We want the sha1 of the entire file, so please don't write to fd // directly; use sha1Stream. FILE *stream; #ifdef XP_WIN HANDLE hFile; do { // mkstemp isn't supported so keep trying until we get a file int result = _mktemp_s(name, strlen(name) + 1); hFile = CreateFileA(name, GENERIC_WRITE, 0, nullptr, CREATE_NEW, FILE_ATTRIBUTE_NORMAL, nullptr); } while (GetLastError() == ERROR_FILE_EXISTS); if (hFile == INVALID_HANDLE_VALUE) { NS_RUNTIMEABORT("Um, how did we get here?"); } // http://support.microsoft.com/kb/139640 int fd = _open_osfhandle((intptr_t)hFile, _O_APPEND); if (fd == -1) { NS_RUNTIMEABORT("Um, how did we get here?"); } stream = _fdopen(fd, "w"); #else int fd = mkstemp(name); stream = fdopen(fd, "w"); #endif SHA1Stream sha1Stream(stream); size_t numModules = stack.GetNumModules(); sha1Stream.Printf("%u\n", (unsigned)numModules); for (size_t i = 0; i < numModules; ++i) { Telemetry::ProcessedStack::Module module = stack.GetModule(i); sha1Stream.Printf("%s %s\n", module.mBreakpadId.c_str(), module.mName.c_str()); } size_t numFrames = stack.GetStackSize(); sha1Stream.Printf("%u\n", (unsigned)numFrames); for (size_t i = 0; i < numFrames; ++i) { const Telemetry::ProcessedStack::Frame &frame = stack.GetFrame(i); // NOTE: We write the offsets, while the atos tool expects a value with // the virtual address added. For example, running otool -l on the the firefox // binary shows // cmd LC_SEGMENT_64 // cmdsize 632 // segname __TEXT // vmaddr 0x0000000100000000 // so to print the line matching the offset 123 one has to run // atos -o firefox 0x100000123. sha1Stream.Printf("%d %x\n", frame.mModIndex, (unsigned)frame.mOffset); } SHA1Sum::Hash sha1; sha1Stream.Finish(sha1); // Note: These files should be deleted by telemetry once it reads them. If // there were no telemetry runs by the time we shut down, we just add files // to the existing ones instead of replacing them. Given that each of these // files is a bug to be fixed, that is probably the right thing to do. // We append the sha1 of the contents to the file name. This provides a simple // client side deduplication. nsPrintfCString finalName("%s%s", mProfileDirectory, "/Telemetry.LateWriteFinal-"); for (int i = 0; i < 20; ++i) { finalName.AppendPrintf("%02x", sha1[i]); } PR_Delete(finalName.get()); PR_Rename(name, finalName.get()); #endif } /******************************* Setup/Teardown *******************************/ static StaticAutoPtr sLateWriteObserver; namespace mozilla{ void InitLateWriteChecks() { nsCOMPtr mozFile; NS_GetSpecialDirectory(NS_APP_USER_PROFILE_50_DIR, getter_AddRefs(mozFile)); if (mozFile) { nsAutoCString nativePath; nsresult rv = mozFile->GetNativePath(nativePath); if (NS_SUCCEEDED(rv) && nativePath.get()) { sLateWriteObserver = new LateWriteObserver(nativePath.get()); } } } void BeginLateWriteChecks() { if (sLateWriteObserver) { IOInterposer::Register( IOInterposeObserver::OpWriteFSync, sLateWriteObserver ); } } void StopLateWriteChecks() { if (sLateWriteObserver) { IOInterposer::Unregister( IOInterposeObserver::OpAll, sLateWriteObserver ); // Deallocation would not be thread-safe, and StopLateWriteChecks() is // called at shutdown and only in special cases. // sLateWriteObserver = nullptr; } } } // namespace mozilla