summaryrefslogtreecommitdiffstats
path: root/xpcom/build/LateWriteChecks.cpp
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--xpcom/build/LateWriteChecks.cpp263
1 files changed, 263 insertions, 0 deletions
diff --git a/xpcom/build/LateWriteChecks.cpp b/xpcom/build/LateWriteChecks.cpp
new file mode 100644
index 0000000000..e3bf73d73c
--- /dev/null
+++ b/xpcom/build/LateWriteChecks.cpp
@@ -0,0 +1,263 @@
+/* -*- 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 "mozilla/Unused.h"
+#include "nsAppDirectoryServiceDefs.h"
+#include "nsDirectoryServiceUtils.h"
+#include "nsLocalFile.h"
+#include "nsPrintfCString.h"
+#include "mozilla/StackWalk.h"
+#include "prio.h"
+
+#ifdef XP_WIN
+# 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"
+
+/*************************** Auxiliary Declarations ***************************/
+
+static MOZ_THREAD_LOCAL(int) tlsSuspendLateWriteChecks;
+
+bool SuspendingLateWriteChecksForCurrentThread() {
+ if (!tlsSuspendLateWriteChecks.init()) {
+ return true;
+ }
+ return tlsSuspendLateWriteChecks.get() > 0;
+}
+
+// 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_FORMAT_PRINTF(2, 3) {
+ MOZ_ASSERT(mFile);
+ va_list list;
+ va_start(list, aFormat);
+ nsAutoCString str;
+ str.AppendVprintf(aFormat, list);
+ va_end(list);
+ mSHA1.update(str.get(), str.Length());
+ mozilla::Unused << fwrite(str.get(), 1, str.Length(), mFile);
+ }
+ void Finish(mozilla::SHA1Sum::Hash& aHash) {
+ int fd = fileno(mFile);
+ fflush(mFile);
+ MozillaUnRegisterDebugFD(fd);
+ fclose(mFile);
+ mSHA1.finish(aHash);
+ mFile = nullptr;
+ }
+
+ private:
+ FILE* mFile;
+ mozilla::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 mozilla::IOInterposeObserver {
+ using char_type = mozilla::filesystem::Path::value_type;
+
+ public:
+ explicit LateWriteObserver(const char_type* aProfileDirectory)
+ : mProfileDirectory(NS_xstrdup(aProfileDirectory)) {}
+ ~LateWriteObserver() {
+ free(mProfileDirectory);
+ mProfileDirectory = nullptr;
+ }
+
+ void Observe(
+ mozilla::IOInterposeObserver::Observation& aObservation) override;
+
+ private:
+ char_type* mProfileDirectory;
+};
+
+void LateWriteObserver::Observe(
+ mozilla::IOInterposeObserver::Observation& aOb) {
+ if (SuspendingLateWriteChecksForCurrentThread()) {
+ return;
+ }
+
+#ifdef DEBUG
+ MOZ_CRASH();
+#endif
+
+ // If we can't record then abort
+ if (!mozilla::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, nullptr, /* maxFrames */ 0, &rawStack);
+ mozilla::Telemetry::ProcessedStack stack =
+ mozilla::Telemetry::GetStackAndModules(rawStack);
+
+ nsTAutoString<char_type> nameAux(mProfileDirectory);
+ nameAux.AppendLiteral(NS_SLASH "Telemetry.LateWriteTmpXXXXXX");
+ char_type* name = nameAux.BeginWriting();
+
+ // 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
+ _wmktemp_s(char16ptr_t(name), NS_strlen(name) + 1);
+ hFile = CreateFileW(char16ptr_t(name), GENERIC_WRITE, 0, nullptr,
+ CREATE_NEW, FILE_ATTRIBUTE_NORMAL, nullptr);
+ } while (GetLastError() == ERROR_FILE_EXISTS);
+
+ if (hFile == INVALID_HANDLE_VALUE) {
+ MOZ_CRASH("Um, how did we get here?");
+ }
+
+ // http://support.microsoft.com/kb/139640
+ int fd = _open_osfhandle((intptr_t)hFile, _O_APPEND);
+ if (fd == -1) {
+ MOZ_CRASH("Um, how did we get here?");
+ }
+
+ stream = _fdopen(fd, "w");
+#else
+ int fd = mkstemp(name);
+ if (fd == -1) {
+ MOZ_CRASH("mkstemp failed");
+ }
+ 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) {
+ mozilla::Telemetry::ProcessedStack::Module module = stack.GetModule(i);
+ sha1Stream.Printf("%s %s\n", module.mBreakpadId.get(),
+ NS_ConvertUTF16toUTF8(module.mName).get());
+ }
+
+ size_t numFrames = stack.GetStackSize();
+ sha1Stream.Printf("%u\n", (unsigned)numFrames);
+ for (size_t i = 0; i < numFrames; ++i) {
+ const mozilla::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);
+ }
+
+ mozilla::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.
+ nsAutoString finalName(u"Telemetry.LateWriteFinal-"_ns);
+ for (int i = 0; i < 20; ++i) {
+ finalName.AppendPrintf("%02x", sha1[i]);
+ }
+ RefPtr<nsLocalFile> file = new nsLocalFile(nameAux);
+ file->RenameTo(nullptr, finalName);
+}
+
+/******************************* Setup/Teardown *******************************/
+
+static mozilla::StaticAutoPtr<LateWriteObserver> sLateWriteObserver;
+
+namespace mozilla {
+
+void InitLateWriteChecks() {
+ nsCOMPtr<nsIFile> mozFile;
+ NS_GetSpecialDirectory(NS_APP_USER_PROFILE_50_DIR, getter_AddRefs(mozFile));
+ if (mozFile) {
+ PathString nativePath = mozFile->NativePath();
+ if (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;
+ }
+}
+
+void PushSuspendLateWriteChecks() {
+ if (!tlsSuspendLateWriteChecks.init()) {
+ return;
+ }
+ tlsSuspendLateWriteChecks.set(tlsSuspendLateWriteChecks.get() + 1);
+}
+
+void PopSuspendLateWriteChecks() {
+ if (!tlsSuspendLateWriteChecks.init()) {
+ return;
+ }
+ int current = tlsSuspendLateWriteChecks.get();
+ MOZ_ASSERT(current > 0);
+ tlsSuspendLateWriteChecks.set(current - 1);
+}
+
+} // namespace mozilla
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-12 15:56:16 +0000