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-rw-r--r--xpcom/build/LateWriteChecks.cpp258
1 files changed, 258 insertions, 0 deletions
diff --git a/xpcom/build/LateWriteChecks.cpp b/xpcom/build/LateWriteChecks.cpp
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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 <algorithm>
+
+#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 "mozilla/StackWalk.h"
+#include "plstr.h"
+#include "prio.h"
+
+#ifdef XP_WIN
+#define NS_T(str) L ## str
+#define NS_SLASH "\\"
+#include <fcntl.h>
+#include <io.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+#include <windows.h>
+#else
+#define NS_SLASH "/"
+#endif
+
+#include "LateWriteChecks.h"
+
+#define OBSERVE_LATE_WRITES
+
+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* aStream)
+ : mFile(aStream)
+ {
+ 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(uint32_t aFrameNumber, void* aPC, void* aSP, void* aClosure)
+{
+ std::vector<uintptr_t>* stack =
+ static_cast<std::vector<uintptr_t>*>(aClosure);
+ stack->push_back(reinterpret_cast<uintptr_t>(aPC));
+}
+
+/**************************** Late-Write Observer ****************************/
+
+/**
+ * An implementation of IOInterposeObserver to be registered with IOInterposer.
+ * This observer logs all writes as late writes.
+ */
+class LateWriteObserver final : public IOInterposeObserver
+{
+public:
+ explicit 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::CanRecordExtended()) {
+ 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<uintptr_t> rawStack;
+
+ MozStackWalk(RecordStackWalker, /* skipFrames */ 0, /* maxFrames */ 0,
+ reinterpret_cast<void*>(&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<LateWriteObserver> sLateWriteObserver;
+
+namespace mozilla {
+
+void
+InitLateWriteChecks()
+{
+ nsCOMPtr<nsIFile> 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