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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
#include <algorithm>
#include "mozilla/IOInterposer.h"
#include "mozilla/PoisonIOInterposer.h"
#include "mozilla/ProcessedStack.h"
#include "mozilla/SHA1.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?");
}
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