1 files changed, 407 insertions, 0 deletions
diff --git a/xpcom/glue/standalone/nsXPCOMGlue.cpp b/xpcom/glue/standalone/nsXPCOMGlue.cpp
new file mode 100644
index 0000000000..e8d48193e2
--- /dev/null
+++ b/xpcom/glue/standalone/nsXPCOMGlue.cpp
@@ -0,0 +1,407 @@
+/* -*- 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 "mozilla/Bootstrap.h"
+
+#include "nsXPCOMPrivate.h"
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "mozilla/FileUtils.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/Try.h"
+#include "mozilla/UniquePtr.h"
+#include "mozilla/UniquePtrExtensions.h"
+
+using namespace mozilla;
+
+#define XPCOM_DEPENDENT_LIBS_LIST "dependentlibs.list"
+
+#if defined(XP_WIN)
+#  define READ_TEXTMODE L"rt"
+#else
+#  define READ_TEXTMODE "r"
+#endif
+
+typedef void (*NSFuncPtr)();
+
+#if defined(XP_WIN)
+#  include <windows.h>
+using LibHandleType = HMODULE;
+#else
+using LibHandleType = void*;
+#endif
+
+using LibHandleResult = ::mozilla::Result<LibHandleType, DLErrorType>;
+
+#if defined(XP_WIN)
+#  include <mbstring.h>
+#  include "mozilla/PreXULSkeletonUI.h"
+
+static LibHandleResult GetLibHandle(pathstr_t aDependentLib) {
+  LibHandleType libHandle =
+      LoadLibraryExW(aDependentLib, nullptr, LOAD_WITH_ALTERED_SEARCH_PATH);
+
+  if (!libHandle) {
+    DWORD err = GetLastError();
+#  if defined(DEBUG)
+    LPWSTR lpMsgBuf;
+    FormatMessageW(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM |
+                       FORMAT_MESSAGE_IGNORE_INSERTS,
+                   nullptr, err, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+                   (LPWSTR)&lpMsgBuf, 0, nullptr);
+    wprintf(L"Error loading %ls: %s\n", aDependentLib, lpMsgBuf);
+    LocalFree(lpMsgBuf);
+#  endif  // defined(DEBUG)
+    return Err(err);
+  }
+
+  return libHandle;
+}
+
+static NSFuncPtr GetSymbol(LibHandleType aLibHandle, const char* aSymbol) {
+  return (NSFuncPtr)GetProcAddress(aLibHandle, aSymbol);
+}
+
+static void CloseLibHandle(LibHandleType aLibHandle) {
+  FreeLibrary(aLibHandle);
+}
+
+#else
+#  include <dlfcn.h>
+
+#  if defined(MOZ_LINKER)
+extern "C" {
+NS_HIDDEN __typeof(dlopen) __wrap_dlopen;
+NS_HIDDEN __typeof(dlsym) __wrap_dlsym;
+NS_HIDDEN __typeof(dlclose) __wrap_dlclose;
+}
+
+#    define dlopen __wrap_dlopen
+#    define dlsym __wrap_dlsym
+#    define dlclose __wrap_dlclose
+#  endif
+
+static LibHandleResult GetLibHandle(pathstr_t aDependentLib) {
+  LibHandleType libHandle = dlopen(aDependentLib, RTLD_GLOBAL | RTLD_LAZY
+#  ifdef XP_MACOSX
+                                                      | RTLD_FIRST
+#  endif
+  );
+  if (!libHandle) {
+    UniqueFreePtr<char> errMsg(strdup(dlerror()));
+    fprintf(stderr, "XPCOMGlueLoad error for file %s:\n%s\n", aDependentLib,
+            errMsg.get());
+    return Err(std::move(errMsg));
+  }
+  return libHandle;
+}
+
+static NSFuncPtr GetSymbol(LibHandleType aLibHandle, const char* aSymbol) {
+  return (NSFuncPtr)dlsym(aLibHandle, aSymbol);
+}
+
+#  if !defined(MOZ_LINKER) && !defined(__ANDROID__)
+static void CloseLibHandle(LibHandleType aLibHandle) { dlclose(aLibHandle); }
+#  endif
+#endif
+
+struct DependentLib {
+  LibHandleType libHandle;
+  DependentLib* next;
+};
+
+static DependentLib* sTop;
+
+static void AppendDependentLib(LibHandleType aLibHandle) {
+  auto* d = new DependentLib;
+  if (!d) {
+    return;
+  }
+
+  d->next = sTop;
+  d->libHandle = aLibHandle;
+
+  sTop = d;
+}
+
+using ReadDependentCBResult = ::mozilla::Result<::mozilla::Ok, DLErrorType>;
+
+static ReadDependentCBResult ReadDependentCB(
+    pathstr_t aDependentLib, LibLoadingStrategy aLibLoadingStrategy) {
+#if !defined(MOZ_LINKER) && !defined(__ANDROID__)
+  // Don't bother doing a ReadAhead if we're not in the parent process.
+  // What we need from the library should already be in the system file
+  // cache.
+  if (aLibLoadingStrategy == LibLoadingStrategy::ReadAhead) {
+    ReadAheadLib(aDependentLib);
+  }
+#endif
+  LibHandleType libHandle;
+  MOZ_TRY_VAR(libHandle, GetLibHandle(aDependentLib));
+
+  AppendDependentLib(libHandle);
+  return Ok();
+}
+
+#ifdef XP_WIN
+static ReadDependentCBResult ReadDependentCB(
+    const char* aDependentLib, LibLoadingStrategy aLibLoadingStrategy) {
+  wchar_t wideDependentLib[MAX_PATH];
+  MultiByteToWideChar(CP_UTF8, 0, aDependentLib, -1, wideDependentLib,
+                      MAX_PATH);
+  return ReadDependentCB(wideDependentLib, aLibLoadingStrategy);
+}
+
+inline FILE* TS_tfopen(const char* path, const wchar_t* mode) {
+  wchar_t wPath[MAX_PATH];
+  MultiByteToWideChar(CP_UTF8, 0, path, -1, wPath, MAX_PATH);
+  return _wfopen(wPath, mode);
+}
+#else
+inline FILE* TS_tfopen(const char* aPath, const char* aMode) {
+  return fopen(aPath, aMode);
+}
+#endif
+
+#if !defined(MOZ_LINKER) && !defined(__ANDROID__)
+static void XPCOMGlueUnload() {
+  while (sTop) {
+    CloseLibHandle(sTop->libHandle);
+
+    DependentLib* temp = sTop;
+    sTop = sTop->next;
+
+    delete temp;
+  }
+}
+#endif
+
+#if defined(XP_WIN)
+// like strpbrk but finds the *last* char, not the first
+static const char* ns_strrpbrk(const char* string, const char* strCharSet) {
+  const char* found = nullptr;
+  for (; *string; ++string) {
+    for (const char* search = strCharSet; *search; ++search) {
+      if (*search == *string) {
+        found = string;
+        // Since we're looking for the last char, we save "found"
+        // until we're at the end of the string.
+      }
+    }
+  }
+
+  return found;
+}
+#endif
+
+using XPCOMGlueLoadError = BootstrapError;
+using XPCOMGlueLoadResult =
+    ::mozilla::Result<::mozilla::Ok, XPCOMGlueLoadError>;
+
+static XPCOMGlueLoadResult XPCOMGlueLoad(
+    const char* aXPCOMFile, LibLoadingStrategy aLibLoadingStrategy) {
+#if defined(MOZ_LINKER) || defined(__ANDROID__)
+  ReadDependentCBResult readDependentCBResult =
+      ReadDependentCB(aXPCOMFile, aLibLoadingStrategy);
+  if (readDependentCBResult.isErr()) {
+    return Err(AsVariant(readDependentCBResult.unwrapErr()));
+  }
+#else
+  char xpcomDir[MAXPATHLEN];
+#  ifdef XP_WIN
+  const char* lastSlash = ns_strrpbrk(aXPCOMFile, "/\\");
+#  elif XP_MACOSX
+  // On OSX, the dependentlibs.list file lives under Contents/Resources.
+  // However, the actual libraries listed in dependentlibs.list live under
+  // Contents/MacOS. We want to read the list from Contents/Resources, then
+  // load the libraries from Contents/MacOS.
+  const char* tempSlash = strrchr(aXPCOMFile, '/');
+  size_t tempLen = size_t(tempSlash - aXPCOMFile);
+  if (tempLen > MAXPATHLEN) {
+    return Err(AsVariant(NS_ERROR_FAILURE));
+  }
+  char tempBuffer[MAXPATHLEN];
+  memcpy(tempBuffer, aXPCOMFile, tempLen);
+  tempBuffer[tempLen] = '\0';
+  const char* slash = strrchr(tempBuffer, '/');
+  tempLen = size_t(slash - tempBuffer);
+  const char* lastSlash = aXPCOMFile + tempLen;
+#  else
+  const char* lastSlash = strrchr(aXPCOMFile, '/');
+#  endif
+  char* cursor;
+  if (lastSlash) {
+    size_t len = size_t(lastSlash - aXPCOMFile);
+
+    if (len > MAXPATHLEN - sizeof(XPCOM_FILE_PATH_SEPARATOR
+#  ifdef XP_MACOSX
+                                  "Resources" XPCOM_FILE_PATH_SEPARATOR
+#  endif
+                                      XPCOM_DEPENDENT_LIBS_LIST)) {
+      return Err(AsVariant(NS_ERROR_FAILURE));
+    }
+    memcpy(xpcomDir, aXPCOMFile, len);
+    strcpy(xpcomDir + len, XPCOM_FILE_PATH_SEPARATOR
+#  ifdef XP_MACOSX
+           "Resources" XPCOM_FILE_PATH_SEPARATOR
+#  endif
+               XPCOM_DEPENDENT_LIBS_LIST);
+    cursor = xpcomDir + len + 1;
+  } else {
+    strcpy(xpcomDir, XPCOM_DEPENDENT_LIBS_LIST);
+    cursor = xpcomDir;
+  }
+
+  if (getenv("MOZ_RUN_GTEST")
+#  ifdef FUZZING
+      || getenv("FUZZER")
+#  endif
+  ) {
+    strcat(xpcomDir, ".gtest");
+  }
+
+  const auto flist = TS_tfopen(xpcomDir, READ_TEXTMODE);
+  const auto cleanup = MakeScopeExit([&]() {
+    if (flist) {
+      fclose(flist);
+    }
+  });
+  if (!flist) {
+    return Err(AsVariant(NS_ERROR_FAILURE));
+  }
+
+#  ifdef XP_MACOSX
+  tempLen = size_t(cursor - xpcomDir);
+  if (tempLen > MAXPATHLEN - sizeof("MacOS" XPCOM_FILE_PATH_SEPARATOR) - 1) {
+    return Err(AsVariant(NS_ERROR_FAILURE));
+  }
+  strcpy(cursor, "MacOS" XPCOM_FILE_PATH_SEPARATOR);
+  cursor += strlen(cursor);
+#  endif
+  *cursor = '\0';
+
+  char buffer[MAXPATHLEN];
+
+  while (fgets(buffer, sizeof(buffer), flist)) {
+    int l = strlen(buffer);
+
+    // ignore empty lines and comments
+    if (l == 0 || *buffer == '#') {
+      continue;
+    }
+
+    // cut the trailing newline, if present
+    if (buffer[l - 1] == '\n') {
+      buffer[l - 1] = '\0';
+    }
+
+    if (l + size_t(cursor - xpcomDir) > MAXPATHLEN) {
+      return Err(AsVariant(NS_ERROR_FAILURE));
+    }
+
+    strcpy(cursor, buffer);
+    ReadDependentCBResult readDependentCBResult =
+        ReadDependentCB(xpcomDir, aLibLoadingStrategy);
+    if (readDependentCBResult.isErr()) {
+      XPCOMGlueUnload();
+      return Err(AsVariant(readDependentCBResult.unwrapErr()));
+    }
+
+#  ifdef XP_WIN
+    // We call PollPreXULSkeletonUIEvents here in order to not get flagged by
+    // Windows as nonresponsive. In order to not be flagged as such, we seem to
+    // simply need to respond to *a* message every few seconds. The halfway
+    // point on slow systems between process start and nsWindow taking over the
+    // skeleton UI window seems to be XUL being loaded. Accordingly, placing
+    // this call here covers the most ground (as we will call this after
+    // prefetching and loading all of the dlls in dependentlibs.list, which
+    // includes xul.dll.)
+    PollPreXULSkeletonUIEvents();
+#  endif
+  }
+#endif
+  return Ok();
+}
+
+#if defined(MOZ_WIDGET_GTK) && \
+    (defined(MOZ_MEMORY) || defined(__FreeBSD__) || defined(__NetBSD__))
+#  define MOZ_GSLICE_INIT
+#endif
+
+#ifdef MOZ_GSLICE_INIT
+#  include <glib.h>
+
+class GSliceInit {
+ public:
+  GSliceInit() {
+    mHadGSlice = bool(getenv("G_SLICE"));
+    if (!mHadGSlice) {
+      // Disable the slice allocator, since jemalloc already uses similar layout
+      // algorithms, and using a sub-allocator tends to increase fragmentation.
+      // This must be done before g_thread_init() is called.
+      // glib >= 2.36 initializes g_slice as a side effect of its various static
+      // initializers, so this needs to happen before glib is loaded, which is
+      // this is hooked in XPCOMGlueStartup before libxul is loaded. This
+      // relies on the main executable not depending on glib.
+      setenv("G_SLICE", "always-malloc", 1);
+    }
+  }
+
+  ~GSliceInit() {
+    if (!mHadGSlice) {
+      unsetenv("G_SLICE");
+    }
+  }
+
+ private:
+  bool mHadGSlice;
+};
+#endif
+
+namespace mozilla {
+
+BootstrapResult GetBootstrap(const char* aXPCOMFile,
+                             LibLoadingStrategy aLibLoadingStrategy) {
+#ifdef MOZ_GSLICE_INIT
+  GSliceInit gSliceInit;
+#endif
+
+  if (!aXPCOMFile) {
+    return Err(AsVariant(NS_ERROR_INVALID_ARG));
+  }
+
+  char* lastSlash =
+      strrchr(const_cast<char*>(aXPCOMFile), XPCOM_FILE_PATH_SEPARATOR[0]);
+  if (!lastSlash) {
+    return Err(AsVariant(NS_ERROR_FILE_INVALID_PATH));
+  }
+
+  size_t base_len = size_t(lastSlash - aXPCOMFile) + 1;
+
+  UniqueFreePtr<char> file(
+      reinterpret_cast<char*>(malloc(base_len + sizeof(XPCOM_DLL))));
+  memcpy(file.get(), aXPCOMFile, base_len);
+  memcpy(file.get() + base_len, XPCOM_DLL, sizeof(XPCOM_DLL));
+
+  MOZ_TRY(XPCOMGlueLoad(file.get(), aLibLoadingStrategy));
+
+  if (!sTop) {
+    return Err(AsVariant(NS_ERROR_NOT_AVAILABLE));
+  }
+  GetBootstrapType func =
+      (GetBootstrapType)GetSymbol(sTop->libHandle, "XRE_GetBootstrap");
+  if (!func) {
+    return Err(AsVariant(NS_ERROR_NOT_AVAILABLE));
+  }
+
+  Bootstrap::UniquePtr b;
+  (*func)(b);
+
+  return b;
+}
+
+}  // namespace mozilla