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diff --git a/xpcom/build/PoisonIOInterposerMac.cpp b/xpcom/build/PoisonIOInterposerMac.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 "PoisonIOInterposer.h"
+// Disabled until bug 1658385 is fixed.
+#ifndef __aarch64__
+# include "mach_override.h"
+#endif
+
+#include "mozilla/ArrayUtils.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/DebugOnly.h"
+#include "mozilla/IOInterposer.h"
+#include "mozilla/Mutex.h"
+#include "mozilla/ProcessedStack.h"
+#include "mozilla/Telemetry.h"
+#include "mozilla/UniquePtrExtensions.h"
+#include "nsPrintfCString.h"
+#include "mozilla/StackWalk.h"
+#include "nsTraceRefcnt.h"
+#include "prio.h"
+
+#include <algorithm>
+#include <vector>
+
+#include <sys/param.h>
+#include <sys/stat.h>
+#include <sys/socket.h>
+#include <sys/uio.h>
+#include <aio.h>
+#include <dlfcn.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#ifdef MOZ_REPLACE_MALLOC
+# include "replace_malloc_bridge.h"
+#endif
+
+namespace {
+
+// Bit tracking if poisoned writes are enabled
+static bool sIsEnabled = false;
+
+// Check if writes are dirty before reporting IO
+static bool sOnlyReportDirtyWrites = false;
+
+// Routines for write validation
+bool IsValidWrite(int aFd, const void* aWbuf, size_t aCount);
+bool IsIPCWrite(int aFd, const struct stat& aBuf);
+
+/******************************** IO AutoTimer ********************************/
+
+/**
+ * RAII class for timing the duration of an I/O call and reporting the result
+ * to the mozilla::IOInterposeObserver API.
+ */
+class MacIOAutoObservation : public mozilla::IOInterposeObserver::Observation {
+ public:
+ MacIOAutoObservation(mozilla::IOInterposeObserver::Operation aOp, int aFd)
+ : mozilla::IOInterposeObserver::Observation(
+ aOp, sReference, sIsEnabled && !mozilla::IsDebugFile(aFd)),
+ mFd(aFd),
+ mHasQueriedFilename(false) {}
+
+ MacIOAutoObservation(mozilla::IOInterposeObserver::Operation aOp, int aFd,
+ const void* aBuf, size_t aCount)
+ : mozilla::IOInterposeObserver::Observation(
+ aOp, sReference,
+ sIsEnabled && !mozilla::IsDebugFile(aFd) &&
+ IsValidWrite(aFd, aBuf, aCount)),
+ mFd(aFd),
+ mHasQueriedFilename(false) {}
+
+ // Custom implementation of
+ // mozilla::IOInterposeObserver::Observation::Filename
+ void Filename(nsAString& aFilename) override;
+
+ ~MacIOAutoObservation() { Report(); }
+
+ private:
+ int mFd;
+ bool mHasQueriedFilename;
+ nsString mFilename;
+ static const char* sReference;
+};
+
+const char* MacIOAutoObservation::sReference = "PoisonIOInterposer";
+
+// Get filename for this observation
+void MacIOAutoObservation::Filename(nsAString& aFilename) {
+ // If mHasQueriedFilename is true, then we already have it
+ if (mHasQueriedFilename) {
+ aFilename = mFilename;
+ return;
+ }
+
+ char filename[MAXPATHLEN];
+ if (fcntl(mFd, F_GETPATH, filename) != -1) {
+ CopyUTF8toUTF16(filename, mFilename);
+ } else {
+ mFilename.Truncate();
+ }
+ mHasQueriedFilename = true;
+
+ aFilename = mFilename;
+}
+
+/****************************** Write Validation ******************************/
+
+// We want to detect "actual" writes, not IPC. Some IPC mechanisms are
+// implemented with file descriptors, so filter them out.
+bool IsIPCWrite(int aFd, const struct stat& aBuf) {
+ if ((aBuf.st_mode & S_IFMT) == S_IFIFO) {
+ return true;
+ }
+
+ if ((aBuf.st_mode & S_IFMT) != S_IFSOCK) {
+ return false;
+ }
+
+ sockaddr_storage address;
+ socklen_t len = sizeof(address);
+ if (getsockname(aFd, (sockaddr*)&address, &len) != 0) {
+ return true; // Ignore the aFd if we can't find what it is.
+ }
+
+ return address.ss_family == AF_UNIX;
+}
+
+// We want to report actual disk IO not things that don't move bits on the disk
+bool IsValidWrite(int aFd, const void* aWbuf, size_t aCount) {
+ // Ignore writes of zero bytes, Firefox does some during shutdown.
+ if (aCount == 0) {
+ return false;
+ }
+
+ {
+ struct stat buf;
+ int rv = fstat(aFd, &buf);
+ if (rv != 0) {
+ return true;
+ }
+
+ if (IsIPCWrite(aFd, buf)) {
+ return false;
+ }
+ }
+
+ // For writev we pass a nullptr aWbuf. We should only get here from
+ // dbm, and it uses write, so assert that we have aWbuf.
+ if (!aWbuf) {
+ return true;
+ }
+
+ // Break, here if we're allowed to report non-dirty writes
+ if (!sOnlyReportDirtyWrites) {
+ return true;
+ }
+
+ // As a really bad hack, accept writes that don't change the on disk
+ // content. This is needed because dbm doesn't keep track of dirty bits
+ // and can end up writing the same data to disk twice. Once when the
+ // user (nss) asks it to sync and once when closing the database.
+ auto wbuf2 = mozilla::MakeUniqueFallible<char[]>(aCount);
+ if (!wbuf2) {
+ return true;
+ }
+ off_t pos = lseek(aFd, 0, SEEK_CUR);
+ if (pos == -1) {
+ return true;
+ }
+ ssize_t r = read(aFd, wbuf2.get(), aCount);
+ if (r < 0 || (size_t)r != aCount) {
+ return true;
+ }
+ int cmp = memcmp(aWbuf, wbuf2.get(), aCount);
+ if (cmp != 0) {
+ return true;
+ }
+ off_t pos2 = lseek(aFd, pos, SEEK_SET);
+ if (pos2 != pos) {
+ return true;
+ }
+
+ // Otherwise this is not a valid write
+ return false;
+}
+
+/*************************** Function Interception ***************************/
+
+/** Structure for declaration of function override */
+struct FuncData {
+ const char* Name; // Name of the function for the ones we use dlsym
+ const void* Wrapper; // The function that we will replace 'Function' with
+ void* Function; // The function that will be replaced with 'Wrapper'
+ void* Buffer; // Will point to the jump buffer that lets us call
+ // 'Function' after it has been replaced.
+};
+
+// Wrap aio_write. We have not seen it before, so just assert/report it.
+typedef ssize_t (*aio_write_t)(struct aiocb* aAioCbp);
+ssize_t wrap_aio_write(struct aiocb* aAioCbp);
+FuncData aio_write_data = {0, (void*)wrap_aio_write, (void*)aio_write};
+ssize_t wrap_aio_write(struct aiocb* aAioCbp) {
+ MacIOAutoObservation timer(mozilla::IOInterposeObserver::OpWrite,
+ aAioCbp->aio_fildes);
+
+ aio_write_t old_write = (aio_write_t)aio_write_data.Buffer;
+ return old_write(aAioCbp);
+}
+
+// Wrap pwrite-like functions.
+// We have not seen them before, so just assert/report it.
+typedef ssize_t (*pwrite_t)(int aFd, const void* buf, size_t aNumBytes,
+ off_t aOffset);
+template <FuncData& foo>
+ssize_t wrap_pwrite_temp(int aFd, const void* aBuf, size_t aNumBytes,
+ off_t aOffset) {
+ MacIOAutoObservation timer(mozilla::IOInterposeObserver::OpWrite, aFd);
+ pwrite_t old_write = (pwrite_t)foo.Buffer;
+ return old_write(aFd, aBuf, aNumBytes, aOffset);
+}
+
+// Define a FuncData for a pwrite-like functions.
+#define DEFINE_PWRITE_DATA(X, NAME) \
+ FuncData X##_data = {NAME, (void*)wrap_pwrite_temp<X##_data>};
+
+// This exists everywhere.
+DEFINE_PWRITE_DATA(pwrite, "pwrite")
+// These exist on 32 bit OS X
+DEFINE_PWRITE_DATA(pwrite_NOCANCEL_UNIX2003, "pwrite$NOCANCEL$UNIX2003");
+DEFINE_PWRITE_DATA(pwrite_UNIX2003, "pwrite$UNIX2003");
+// This exists on 64 bit OS X
+DEFINE_PWRITE_DATA(pwrite_NOCANCEL, "pwrite$NOCANCEL");
+
+typedef ssize_t (*writev_t)(int aFd, const struct iovec* aIov, int aIovCount);
+template <FuncData& foo>
+ssize_t wrap_writev_temp(int aFd, const struct iovec* aIov, int aIovCount) {
+ MacIOAutoObservation timer(mozilla::IOInterposeObserver::OpWrite, aFd,
+ nullptr, aIovCount);
+ writev_t old_write = (writev_t)foo.Buffer;
+ return old_write(aFd, aIov, aIovCount);
+}
+
+// Define a FuncData for a writev-like functions.
+#define DEFINE_WRITEV_DATA(X, NAME) \
+ FuncData X##_data = {NAME, (void*)wrap_writev_temp<X##_data>};
+
+// This exists everywhere.
+DEFINE_WRITEV_DATA(writev, "writev");
+// These exist on 32 bit OS X
+DEFINE_WRITEV_DATA(writev_NOCANCEL_UNIX2003, "writev$NOCANCEL$UNIX2003");
+DEFINE_WRITEV_DATA(writev_UNIX2003, "writev$UNIX2003");
+// This exists on 64 bit OS X
+DEFINE_WRITEV_DATA(writev_NOCANCEL, "writev$NOCANCEL");
+
+typedef ssize_t (*write_t)(int aFd, const void* aBuf, size_t aCount);
+template <FuncData& foo>
+ssize_t wrap_write_temp(int aFd, const void* aBuf, size_t aCount) {
+ MacIOAutoObservation timer(mozilla::IOInterposeObserver::OpWrite, aFd, aBuf,
+ aCount);
+ write_t old_write = (write_t)foo.Buffer;
+ return old_write(aFd, aBuf, aCount);
+}
+
+// Define a FuncData for a write-like functions.
+#define DEFINE_WRITE_DATA(X, NAME) \
+ FuncData X##_data = {NAME, (void*)wrap_write_temp<X##_data>};
+
+// This exists everywhere.
+DEFINE_WRITE_DATA(write, "write");
+// These exist on 32 bit OS X
+DEFINE_WRITE_DATA(write_NOCANCEL_UNIX2003, "write$NOCANCEL$UNIX2003");
+DEFINE_WRITE_DATA(write_UNIX2003, "write$UNIX2003");
+// This exists on 64 bit OS X
+DEFINE_WRITE_DATA(write_NOCANCEL, "write$NOCANCEL");
+
+FuncData* Functions[] = {&aio_write_data,
+
+ &pwrite_data, &pwrite_NOCANCEL_UNIX2003_data,
+ &pwrite_UNIX2003_data, &pwrite_NOCANCEL_data,
+
+ &write_data, &write_NOCANCEL_UNIX2003_data,
+ &write_UNIX2003_data, &write_NOCANCEL_data,
+
+ &writev_data, &writev_NOCANCEL_UNIX2003_data,
+ &writev_UNIX2003_data, &writev_NOCANCEL_data};
+
+const int NumFunctions = mozilla::ArrayLength(Functions);
+
+} // namespace
+
+/******************************** IO Poisoning ********************************/
+
+namespace mozilla {
+
+void InitPoisonIOInterposer() {
+ // Enable reporting from poisoned write methods
+ sIsEnabled = true;
+
+ // Make sure we only poison writes once!
+ static bool WritesArePoisoned = false;
+ if (WritesArePoisoned) {
+ return;
+ }
+ WritesArePoisoned = true;
+
+ // stdout and stderr are OK.
+ MozillaRegisterDebugFD(1);
+ MozillaRegisterDebugFD(2);
+
+#ifdef MOZ_REPLACE_MALLOC
+ // The contract with InitDebugFd is that the given registry can be used
+ // at any moment, so the instance needs to persist longer than the scope
+ // of this functions.
+ static DebugFdRegistry registry;
+ ReplaceMalloc::InitDebugFd(registry);
+#endif
+
+ for (int i = 0; i < NumFunctions; ++i) {
+ FuncData* d = Functions[i];
+ if (!d->Function) {
+ d->Function = dlsym(RTLD_DEFAULT, d->Name);
+ }
+ if (!d->Function) {
+ continue;
+ }
+#ifndef __aarch64__
+ DebugOnly<mach_error_t> t =
+ mach_override_ptr(d->Function, d->Wrapper, &d->Buffer);
+ MOZ_ASSERT(t == err_none);
+#endif
+ }
+}
+
+void OnlyReportDirtyWrites() { sOnlyReportDirtyWrites = true; }
+
+// Never called! See bug 1647107.
+void ClearPoisonIOInterposer() {
+ // Not sure how or if we can unpoison the functions. Would be nice, but no
+ // worries we won't need to do this anyway.
+ sIsEnabled = false;
+}
+
+} // namespace mozilla
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