Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1309 insertions, 0 deletions

diff --git a/js/src/shell/OSObject.cpp b/js/src/shell/OSObject.cpp
new file mode 100644
index 0000000000..b618d331e0
--- /dev/null
+++ b/js/src/shell/OSObject.cpp
@@ -0,0 +1,1309 @@
+/* -*- 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/. */
+
+// OSObject.h - os object for exposing posix system calls in the JS shell
+
+#include "shell/OSObject.h"
+
+#include "mozilla/ArrayUtils.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/TextUtils.h"
+
+#include <errno.h>
+#include <stdlib.h>
+#ifdef XP_WIN
+#  include <direct.h>
+#  include <process.h>
+#  include <string.h>
+#  include <wchar.h>
+#  include <windows.h>
+#elif __wasi__
+#  include <dirent.h>
+#  include <sys/types.h>
+#  include <unistd.h>
+#else
+#  include <dirent.h>
+#  include <sys/types.h>
+#  include <sys/wait.h>
+#  include <unistd.h>
+#endif
+
+#include "jsapi.h"
+// For JSFunctionSpecWithHelp
+#include "jsfriendapi.h"
+
+#include "gc/GCContext.h"
+#include "js/CharacterEncoding.h"
+#include "js/Conversions.h"
+#include "js/experimental/TypedData.h"  // JS_NewUint8Array
+#include "js/Object.h"                  // JS::GetReservedSlot
+#include "js/PropertyAndElement.h"      // JS_DefineProperty
+#include "js/PropertySpec.h"
+#include "js/Value.h"  // JS::Value
+#include "js/Wrapper.h"
+#include "shell/jsshell.h"
+#include "shell/StringUtils.h"
+#include "util/GetPidProvider.h"  // getpid()
+#include "util/StringBuffer.h"
+#include "util/Text.h"
+#include "util/WindowsWrapper.h"
+#include "vm/JSObject.h"
+#include "vm/TypedArrayObject.h"
+
+#include "vm/JSObject-inl.h"
+
+#ifdef XP_WIN
+#  ifndef PATH_MAX
+#    define PATH_MAX (MAX_PATH > _MAX_DIR ? MAX_PATH : _MAX_DIR)
+#  endif
+#  define getcwd _getcwd
+#elif defined(__wasi__)
+// Nothing.
+#else
+#  include <libgen.h>
+#endif
+
+using js::shell::RCFile;
+
+namespace js {
+namespace shell {
+
+bool IsAbsolutePath(JSLinearString* filename) {
+  size_t length = filename->length();
+
+#ifdef XP_WIN
+  // On Windows there are various forms of absolute paths (see
+  // http://msdn.microsoft.com/en-us/library/windows/desktop/aa365247%28v=vs.85%29.aspx
+  // for details):
+  //
+  //   "\..."
+  //   "\\..."
+  //   "C:\..."
+  //
+  // The first two cases are handled by the common test below so we only need a
+  // specific test for the last one here.
+
+  if (length > 3 && mozilla::IsAsciiAlpha(CharAt(filename, 0)) &&
+      CharAt(filename, 1) == u':' && CharAt(filename, 2) == u'\\') {
+    return true;
+  }
+#endif
+
+  return length > 0 && CharAt(filename, 0) == PathSeparator;
+}
+
+static UniqueChars DirectoryName(JSContext* cx, const char* path) {
+#ifdef XP_WIN
+  UniqueWideChars widePath = JS::EncodeUtf8ToWide(cx, path);
+  if (!widePath) {
+    return nullptr;
+  }
+
+  wchar_t dirName[PATH_MAX + 1];
+  wchar_t* drive = nullptr;
+  wchar_t* fileName = nullptr;
+  wchar_t* fileExt = nullptr;
+
+  // The docs say it can return EINVAL, but the compiler says it's void
+  _wsplitpath(widePath.get(), drive, dirName, fileName, fileExt);
+
+  return JS::EncodeWideToUtf8(cx, dirName);
+#else
+  UniqueChars narrowPath = JS::EncodeUtf8ToNarrow(cx, path);
+  if (!narrowPath) {
+    return nullptr;
+  }
+
+  char dirName[PATH_MAX + 1];
+  strncpy(dirName, narrowPath.get(), PATH_MAX);
+  if (dirName[PATH_MAX - 1] != '\0') {
+    return nullptr;
+  }
+
+#  ifdef __wasi__
+  // dirname() seems not to behave properly with wasi-libc; so we do our own
+  // simple thing here.
+  char* p = dirName + strlen(dirName);
+  bool found = false;
+  while (p > dirName) {
+    if (*p == '/') {
+      found = true;
+      *p = '\0';
+      break;
+    }
+    p--;
+  }
+  if (!found) {
+    // There's no '/'. Possible cases are the following:
+    //  * "."
+    //  * ".."
+    //  * filename only
+    //
+    // dirname() returns "." for all cases.
+    dirName[0] = '.';
+    dirName[1] = '\0';
+  }
+#  else
+  // dirname(dirName) might return dirName, or it might return a
+  // statically-allocated string
+  memmove(dirName, dirname(dirName), strlen(dirName) + 1);
+#  endif
+
+  return JS::EncodeNarrowToUtf8(cx, dirName);
+#endif
+}
+
+/*
+ * Resolve a (possibly) relative filename to an absolute path. If
+ * |scriptRelative| is true, then the result will be relative to the directory
+ * containing the currently-running script, or the current working directory if
+ * the currently-running script is "-e" (namely, you're using it from the
+ * command line.) Otherwise, it will be relative to the current working
+ * directory.
+ */
+JSString* ResolvePath(JSContext* cx, HandleString filenameStr,
+                      PathResolutionMode resolveMode) {
+  if (!filenameStr) {
+#ifdef XP_WIN
+    return JS_NewStringCopyZ(cx, "nul");
+#elif defined(__wasi__)
+    MOZ_CRASH("NYI for WASI");
+    return nullptr;
+#else
+    return JS_NewStringCopyZ(cx, "/dev/null");
+#endif
+  }
+
+  Rooted<JSLinearString*> str(cx, JS_EnsureLinearString(cx, filenameStr));
+  if (!str) {
+    return nullptr;
+  }
+
+  if (IsAbsolutePath(str)) {
+    return str;
+  }
+
+  UniqueChars filename = JS_EncodeStringToUTF8(cx, str);
+  if (!filename) {
+    return nullptr;
+  }
+
+  JS::AutoFilename scriptFilename;
+  if (resolveMode == ScriptRelative) {
+    // Get the currently executing script's name.
+    if (!DescribeScriptedCaller(cx, &scriptFilename)) {
+      return nullptr;
+    }
+
+    if (!scriptFilename.get()) {
+      return nullptr;
+    }
+
+    if (strcmp(scriptFilename.get(), "-e") == 0 ||
+        strcmp(scriptFilename.get(), "typein") == 0) {
+      resolveMode = RootRelative;
+    }
+  }
+
+  UniqueChars path;
+  if (resolveMode == ScriptRelative) {
+    path = DirectoryName(cx, scriptFilename.get());
+  } else {
+    path = GetCWD(cx);
+  }
+
+  if (!path) {
+    return nullptr;
+  }
+
+  size_t pathLen = strlen(path.get());
+  size_t filenameLen = strlen(filename.get());
+  size_t resultLen = pathLen + 1 + filenameLen;
+
+  UniqueChars result = cx->make_pod_array<char>(resultLen + 1);
+  if (!result) {
+    return nullptr;
+  }
+  memcpy(result.get(), path.get(), pathLen);
+  result[pathLen] = '/';
+  memcpy(result.get() + pathLen + 1, filename.get(), filenameLen);
+  result[pathLen + 1 + filenameLen] = '\0';
+
+  return JS_NewStringCopyUTF8N(cx, JS::UTF8Chars(result.get(), resultLen));
+}
+
+FILE* OpenFile(JSContext* cx, const char* filename, const char* mode) {
+#ifdef XP_WIN
+  // Maximum valid mode string is "w+xb". Longer strings or strings
+  // containing invalid input lead to undefined behavior.
+  constexpr size_t MaxValidModeLength = 4;
+  wchar_t wideMode[MaxValidModeLength + 1] = {0};
+  for (size_t i = 0; i < MaxValidModeLength && mode[i] != '\0'; i++) {
+    wideMode[i] = mode[i] & 0x7f;
+  }
+
+  UniqueWideChars wideFilename = JS::EncodeUtf8ToWide(cx, filename);
+  if (!wideFilename) {
+    return nullptr;
+  }
+
+  FILE* file = _wfopen(wideFilename.get(), wideMode);
+#else
+  UniqueChars narrowFilename = JS::EncodeUtf8ToNarrow(cx, filename);
+  if (!narrowFilename) {
+    return nullptr;
+  }
+
+  FILE* file = fopen(narrowFilename.get(), mode);
+#endif
+
+  if (!file) {
+    if (UniqueChars error = SystemErrorMessage(cx, errno)) {
+      JS_ReportErrorNumberUTF8(cx, my_GetErrorMessage, nullptr,
+                               JSSMSG_CANT_OPEN, filename, error.get());
+    }
+    return nullptr;
+  }
+  return file;
+}
+
+bool ReadFile(JSContext* cx, const char* filename, FILE* file, char* buffer,
+              size_t length) {
+  size_t cc = fread(buffer, sizeof(char), length, file);
+  if (cc != length) {
+    if (ptrdiff_t(cc) < 0) {
+      if (UniqueChars error = SystemErrorMessage(cx, errno)) {
+        JS_ReportErrorNumberUTF8(cx, my_GetErrorMessage, nullptr,
+                                 JSSMSG_CANT_READ, filename, error.get());
+      }
+    } else {
+      JS_ReportErrorUTF8(cx, "can't read %s: short read", filename);
+    }
+    return false;
+  }
+  return true;
+}
+
+bool FileSize(JSContext* cx, const char* filename, FILE* file, size_t* size) {
+  if (fseek(file, 0, SEEK_END) != 0) {
+    JS_ReportErrorUTF8(cx, "can't seek end of %s", filename);
+    return false;
+  }
+
+  size_t len = ftell(file);
+  if (fseek(file, 0, SEEK_SET) != 0) {
+    JS_ReportErrorUTF8(cx, "can't seek start of %s", filename);
+    return false;
+  }
+
+  *size = len;
+  return true;
+}
+
+JSObject* FileAsTypedArray(JSContext* cx, JS::HandleString pathnameStr) {
+  UniqueChars pathname = JS_EncodeStringToUTF8(cx, pathnameStr);
+  if (!pathname) {
+    return nullptr;
+  }
+
+  FILE* file = OpenFile(cx, pathname.get(), "rb");
+  if (!file) {
+    return nullptr;
+  }
+  AutoCloseFile autoClose(file);
+
+  size_t len;
+  if (!FileSize(cx, pathname.get(), file, &len)) {
+    return nullptr;
+  }
+
+  if (len > ArrayBufferObject::MaxByteLength) {
+    JS_ReportErrorUTF8(cx, "file %s is too large for a Uint8Array",
+                       pathname.get());
+    return nullptr;
+  }
+
+  JS::Rooted<JSObject*> obj(cx, JS_NewUint8Array(cx, len));
+  if (!obj) {
+    return nullptr;
+  }
+
+  js::TypedArrayObject& ta = obj->as<js::TypedArrayObject>();
+  if (ta.isSharedMemory()) {
+    // Must opt in to use shared memory.  For now, don't.
+    //
+    // (It is incorrect to read into the buffer without
+    // synchronization since that can create a race.  A
+    // lock here won't fix it - both sides must
+    // participate.  So what one must do is to create a
+    // temporary buffer, read into that, and use a
+    // race-safe primitive to copy memory into the
+    // buffer.)
+    JS_ReportErrorUTF8(cx, "can't read %s: shared memory buffer",
+                       pathname.get());
+    return nullptr;
+  }
+
+  char* buf = static_cast<char*>(ta.dataPointerUnshared());
+  if (!ReadFile(cx, pathname.get(), file, buf, len)) {
+    return nullptr;
+  }
+
+  return obj;
+}
+
+/**
+ * Return the current working directory or |null| on failure.
+ */
+UniqueChars GetCWD(JSContext* cx) {
+#ifdef XP_WIN
+  wchar_t buffer[PATH_MAX + 1];
+  const wchar_t* cwd = _wgetcwd(buffer, PATH_MAX);
+  if (!cwd) {
+    return nullptr;
+  }
+  return JS::EncodeWideToUtf8(cx, buffer);
+#else
+  char buffer[PATH_MAX + 1];
+  const char* cwd = getcwd(buffer, PATH_MAX);
+  if (!cwd) {
+    return nullptr;
+  }
+  return JS::EncodeNarrowToUtf8(cx, buffer);
+#endif
+}
+
+static bool ReadFile(JSContext* cx, unsigned argc, Value* vp,
+                     PathResolutionMode resolveMode) {
+  CallArgs args = CallArgsFromVp(argc, vp);
+
+  if (args.length() < 1 || args.length() > 2) {
+    JS_ReportErrorNumberASCII(
+        cx, js::shell::my_GetErrorMessage, nullptr,
+        args.length() < 1 ? JSSMSG_NOT_ENOUGH_ARGS : JSSMSG_TOO_MANY_ARGS,
+        "snarf");
+    return false;
+  }
+
+  if (!args[0].isString() || (args.length() == 2 && !args[1].isString())) {
+    JS_ReportErrorNumberASCII(cx, js::shell::my_GetErrorMessage, nullptr,
+                              JSSMSG_INVALID_ARGS, "snarf");
+    return false;
+  }
+
+  JS::Rooted<JSString*> givenPath(cx, args[0].toString());
+  JS::Rooted<JSString*> str(cx,
+                            js::shell::ResolvePath(cx, givenPath, resolveMode));
+  if (!str) {
+    return false;
+  }
+
+  if (args.length() > 1) {
+    JSString* opt = JS::ToString(cx, args[1]);
+    if (!opt) {
+      return false;
+    }
+    bool match;
+    if (!JS_StringEqualsLiteral(cx, opt, "binary", &match)) {
+      return false;
+    }
+    if (match) {
+      JSObject* obj;
+      if (!(obj = FileAsTypedArray(cx, str))) {
+        return false;
+      }
+      args.rval().setObject(*obj);
+      return true;
+    }
+  }
+
+  if (!(str = FileAsString(cx, str))) {
+    return false;
+  }
+  args.rval().setString(str);
+  return true;
+}
+
+static bool osfile_readFile(JSContext* cx, unsigned argc, Value* vp) {
+  return ReadFile(cx, argc, vp, RootRelative);
+}
+
+static bool osfile_readRelativeToScript(JSContext* cx, unsigned argc,
+                                        Value* vp) {
+  return ReadFile(cx, argc, vp, ScriptRelative);
+}
+
+static bool ListDir(JSContext* cx, unsigned argc, Value* vp,
+                    PathResolutionMode resolveMode) {
+  CallArgs args = CallArgsFromVp(argc, vp);
+
+  if (args.length() != 1) {
+    JS_ReportErrorASCII(cx, "os.file.listDir requires 1 argument");
+    return false;
+  }
+
+  if (!args[0].isString()) {
+    JS_ReportErrorNumberASCII(cx, js::shell::my_GetErrorMessage, nullptr,
+                              JSSMSG_INVALID_ARGS, "os.file.listDir");
+    return false;
+  }
+
+  RootedString givenPath(cx, args[0].toString());
+  RootedString str(cx, ResolvePath(cx, givenPath, resolveMode));
+  if (!str) {
+    return false;
+  }
+
+  UniqueChars pathname = JS_EncodeStringToUTF8(cx, str);
+  if (!pathname) {
+    JS_ReportErrorASCII(cx, "os.file.listDir cannot convert path to Latin1");
+    return false;
+  }
+
+  RootedValueVector elems(cx);
+  auto append = [&](const char* name) -> bool {
+    if (!(str = JS_NewStringCopyZ(cx, name))) {
+      return false;
+    }
+    if (!elems.append(StringValue(str))) {
+      js::ReportOutOfMemory(cx);
+      return false;
+    }
+    return true;
+  };
+
+#if defined(XP_UNIX)
+  {
+    DIR* dir = opendir(pathname.get());
+    if (!dir) {
+      JS_ReportErrorASCII(cx, "os.file.listDir is unable to open: %s",
+                          pathname.get());
+      return false;
+    }
+    auto close = mozilla::MakeScopeExit([&] {
+      if (closedir(dir) != 0) {
+        MOZ_CRASH("Could not close dir");
+      }
+    });
+
+    while (struct dirent* entry = readdir(dir)) {
+      if (!append(entry->d_name)) {
+        return false;
+      }
+    }
+  }
+#elif defined(XP_WIN)
+  {
+    const size_t pathlen = strlen(pathname.get());
+    Vector<char> pattern(cx);
+    if (!pattern.append(pathname.get(), pathlen) ||
+        !pattern.append(PathSeparator) || !pattern.append("*", 2)) {
+      js::ReportOutOfMemory(cx);
+      return false;
+    }
+
+    WIN32_FIND_DATAA FindFileData;
+    HANDLE hFind = FindFirstFileA(pattern.begin(), &FindFileData);
+    auto close = mozilla::MakeScopeExit([&] {
+      if (!FindClose(hFind)) {
+        MOZ_CRASH("Could not close Find");
+      }
+    });
+    for (bool found = (hFind != INVALID_HANDLE_VALUE); found;
+         found = FindNextFileA(hFind, &FindFileData)) {
+      if (!append(FindFileData.cFileName)) {
+        return false;
+      }
+    }
+  }
+#endif
+
+  JSObject* array = JS::NewArrayObject(cx, elems);
+  if (!array) {
+    return false;
+  }
+
+  args.rval().setObject(*array);
+  return true;
+}
+
+static bool osfile_listDir(JSContext* cx, unsigned argc, Value* vp) {
+  return ListDir(cx, argc, vp, RootRelative);
+}
+
+static bool osfile_listDirRelativeToScript(JSContext* cx, unsigned argc,
+                                           Value* vp) {
+  return ListDir(cx, argc, vp, ScriptRelative);
+}
+
+static bool osfile_writeTypedArrayToFile(JSContext* cx, unsigned argc,
+                                         Value* vp) {
+  CallArgs args = CallArgsFromVp(argc, vp);
+
+  if (args.length() != 2 || !args[0].isString() || !args[1].isObject() ||
+      !args[1].toObject().is<TypedArrayObject>()) {
+    JS_ReportErrorNumberASCII(cx, my_GetErrorMessage, nullptr,
+                              JSSMSG_INVALID_ARGS, "writeTypedArrayToFile");
+    return false;
+  }
+
+  RootedString givenPath(cx, args[0].toString());
+  RootedString str(cx, ResolvePath(cx, givenPath, RootRelative));
+  if (!str) {
+    return false;
+  }
+
+  UniqueChars filename = JS_EncodeStringToUTF8(cx, str);
+  if (!filename) {
+    return false;
+  }
+
+  FILE* file = OpenFile(cx, filename.get(), "wb");
+  if (!file) {
+    return false;
+  }
+  AutoCloseFile autoClose(file);
+
+  TypedArrayObject* obj = &args[1].toObject().as<TypedArrayObject>();
+
+  if (obj->isSharedMemory()) {
+    // Must opt in to use shared memory.  For now, don't.
+    //
+    // See further comments in FileAsTypedArray, above.
+    JS_ReportErrorUTF8(cx, "can't write %s: shared memory buffer",
+                       filename.get());
+    return false;
+  }
+  void* buf = obj->dataPointerUnshared();
+  size_t length = obj->length();
+  if (fwrite(buf, obj->bytesPerElement(), length, file) != length ||
+      !autoClose.release()) {
+    JS_ReportErrorUTF8(cx, "can't write %s", filename.get());
+    return false;
+  }
+
+  args.rval().setUndefined();
+  return true;
+}
+
+/* static */
+RCFile* RCFile::create(JSContext* cx, const char* filename, const char* mode) {
+  FILE* fp = OpenFile(cx, filename, mode);
+  if (!fp) {
+    return nullptr;
+  }
+
+  RCFile* file = cx->new_<RCFile>(fp);
+  if (!file) {
+    fclose(fp);
+    return nullptr;
+  }
+
+  return file;
+}
+
+void RCFile::close() {
+  if (fp) {
+    fclose(fp);
+  }
+  fp = nullptr;
+}
+
+bool RCFile::release() {
+  if (--numRefs) {
+    return false;
+  }
+  this->close();
+  return true;
+}
+
+class FileObject : public NativeObject {
+  enum : uint32_t { FILE_SLOT = 0, NUM_SLOTS };
+
+ public:
+  static const JSClass class_;
+
+  static FileObject* create(JSContext* cx, RCFile* file) {
+    FileObject* obj = js::NewBuiltinClassInstance<FileObject>(cx);
+    if (!obj) {
+      return nullptr;
+    }
+
+    InitReservedSlot(obj, FILE_SLOT, file, MemoryUse::FileObjectFile);
+    file->acquire();
+    return obj;
+  }
+
+  static void finalize(JS::GCContext* gcx, JSObject* obj) {
+    FileObject* fileObj = &obj->as<FileObject>();
+    RCFile* file = fileObj->rcFile();
+    gcx->removeCellMemory(obj, sizeof(*file), MemoryUse::FileObjectFile);
+    if (file->release()) {
+      gcx->deleteUntracked(file);
+    }
+  }
+
+  bool isOpen() {
+    RCFile* file = rcFile();
+    return file && file->isOpen();
+  }
+
+  void close() {
+    if (!isOpen()) {
+      return;
+    }
+    rcFile()->close();
+  }
+
+  RCFile* rcFile() {
+    return reinterpret_cast<RCFile*>(
+        JS::GetReservedSlot(this, FILE_SLOT).toPrivate());
+  }
+};
+
+static const JSClassOps FileObjectClassOps = {
+    nullptr,               // addProperty
+    nullptr,               // delProperty
+    nullptr,               // enumerate
+    nullptr,               // newEnumerate
+    nullptr,               // resolve
+    nullptr,               // mayResolve
+    FileObject::finalize,  // finalize
+    nullptr,               // call
+    nullptr,               // construct
+    nullptr,               // trace
+};
+
+const JSClass FileObject::class_ = {
+    "File",
+    JSCLASS_HAS_RESERVED_SLOTS(FileObject::NUM_SLOTS) |
+        JSCLASS_FOREGROUND_FINALIZE,
+    &FileObjectClassOps};
+
+static FileObject* redirect(JSContext* cx, HandleString relFilename,
+                            RCFile** globalFile) {
+  RootedString filename(cx, ResolvePath(cx, relFilename, RootRelative));
+  if (!filename) {
+    return nullptr;
+  }
+  UniqueChars filenameABS = JS_EncodeStringToUTF8(cx, filename);
+  if (!filenameABS) {
+    return nullptr;
+  }
+  RCFile* file = RCFile::create(cx, filenameABS.get(), "wb");
+  if (!file) {
+    return nullptr;
+  }
+
+  // Grant the global gOutFile ownership of the new file, release ownership
+  // of its old file, and return a FileObject owning the old file.
+  file->acquire();  // Global owner of new file
+
+  FileObject* fileObj =
+      FileObject::create(cx, *globalFile);  // Newly created owner of old file
+  if (!fileObj) {
+    file->release();
+    return nullptr;
+  }
+
+  (*globalFile)->release();  // Release (global) ownership of old file.
+  *globalFile = file;
+
+  return fileObj;
+}
+
+static bool Redirect(JSContext* cx, const CallArgs& args, RCFile** outFile) {
+  if (args.length() > 1) {
+    JS_ReportErrorNumberASCII(cx, js::shell::my_GetErrorMessage, nullptr,
+                              JSSMSG_INVALID_ARGS, "redirect");
+    return false;
+  }
+
+  RCFile* oldFile = *outFile;
+  RootedObject oldFileObj(cx, FileObject::create(cx, oldFile));
+  if (!oldFileObj) {
+    return false;
+  }
+
+  if (args.get(0).isUndefined()) {
+    args.rval().setObject(*oldFileObj);
+    return true;
+  }
+
+  if (args[0].isObject()) {
+    Rooted<FileObject*> fileObj(cx,
+                                args[0].toObject().maybeUnwrapIf<FileObject>());
+    if (!fileObj) {
+      JS_ReportErrorNumberASCII(cx, js::shell::my_GetErrorMessage, nullptr,
+                                JSSMSG_INVALID_ARGS, "redirect");
+      return false;
+    }
+
+    // Passed in a FileObject. Create a FileObject for the previous
+    // global file, and set the global file to the passed-in one.
+    *outFile = fileObj->rcFile();
+    (*outFile)->acquire();
+    oldFile->release();
+
+    args.rval().setObject(*oldFileObj);
+    return true;
+  }
+
+  RootedString filename(cx);
+  if (!args[0].isNull()) {
+    filename = JS::ToString(cx, args[0]);
+    if (!filename) {
+      return false;
+    }
+  }
+
+  if (!redirect(cx, filename, outFile)) {
+    return false;
+  }
+
+  args.rval().setObject(*oldFileObj);
+  return true;
+}
+
+static bool osfile_redirectOutput(JSContext* cx, unsigned argc, Value* vp) {
+  CallArgs args = CallArgsFromVp(argc, vp);
+  ShellContext* scx = GetShellContext(cx);
+  return Redirect(cx, args, scx->outFilePtr);
+}
+
+static bool osfile_redirectError(JSContext* cx, unsigned argc, Value* vp) {
+  CallArgs args = CallArgsFromVp(argc, vp);
+  ShellContext* scx = GetShellContext(cx);
+  return Redirect(cx, args, scx->errFilePtr);
+}
+
+static bool osfile_close(JSContext* cx, unsigned argc, Value* vp) {
+  CallArgs args = CallArgsFromVp(argc, vp);
+
+  Rooted<FileObject*> fileObj(cx);
+  if (args.get(0).isObject()) {
+    fileObj = args[0].toObject().maybeUnwrapIf<FileObject>();
+  }
+
+  if (!fileObj) {
+    JS_ReportErrorNumberASCII(cx, js::shell::my_GetErrorMessage, nullptr,
+                              JSSMSG_INVALID_ARGS, "close");
+    return false;
+  }
+
+  fileObj->close();
+
+  args.rval().setUndefined();
+  return true;
+}
+
+// clang-format off
+static const JSFunctionSpecWithHelp osfile_functions[] = {
+    JS_FN_HELP("readFile", osfile_readFile, 1, 0,
+"readFile(filename, [\"binary\"])",
+"  Read entire contents of filename. Returns a string, unless \"binary\" is passed\n"
+"  as the second argument, in which case it returns a Uint8Array. Filename is\n"
+"  relative to the current working directory."),
+
+    JS_FN_HELP("readRelativeToScript", osfile_readRelativeToScript, 1, 0,
+"readRelativeToScript(filename, [\"binary\"])",
+"  Read filename into returned string. Filename is relative to the directory\n"
+"  containing the current script."),
+
+    JS_FN_HELP("listDir", osfile_listDir, 1, 0,
+"listDir(dirname)",
+"  Read entire contents of a directory. The \"dirname\" parameter is relate to the\n"
+"  current working directory. Returns a list of filenames within the given directory.\n"
+"  Note that \".\" and \"..\" are also listed."),
+
+    JS_FN_HELP("listDirRelativeToScript", osfile_listDirRelativeToScript, 1, 0,
+"listDirRelativeToScript(dirname)",
+"  Same as \"listDir\" except that the \"dirname\" is relative to the directory\n"
+"  containing the current script."),
+
+    JS_FS_HELP_END
+};
+// clang-format on
+
+// clang-format off
+static const JSFunctionSpecWithHelp osfile_unsafe_functions[] = {
+    JS_FN_HELP("writeTypedArrayToFile", osfile_writeTypedArrayToFile, 2, 0,
+"writeTypedArrayToFile(filename, data)",
+"  Write the contents of a typed array to the named file."),
+
+    JS_FN_HELP("redirect", osfile_redirectOutput, 1, 0,
+"redirect([path-or-object])",
+"  Redirect print() output to the named file.\n"
+"   Return an opaque object representing the previous destination, which\n"
+"   may be passed into redirect() later to restore the output."),
+
+    JS_FN_HELP("redirectErr", osfile_redirectError, 1, 0,
+"redirectErr([path-or-object])",
+"  Same as redirect(), but for printErr"),
+
+    JS_FN_HELP("close", osfile_close, 1, 0,
+"close(object)",
+"  Close the file returned by an earlier redirect call."),
+
+    JS_FS_HELP_END
+};
+// clang-format on
+
+static bool ospath_isAbsolute(JSContext* cx, unsigned argc, Value* vp) {
+  CallArgs args = CallArgsFromVp(argc, vp);
+
+  if (args.length() != 1 || !args[0].isString()) {
+    JS_ReportErrorNumberASCII(cx, my_GetErrorMessage, nullptr,
+                              JSSMSG_INVALID_ARGS, "isAbsolute");
+    return false;
+  }
+
+  Rooted<JSLinearString*> str(cx,
+                              JS_EnsureLinearString(cx, args[0].toString()));
+  if (!str) {
+    return false;
+  }
+
+  args.rval().setBoolean(IsAbsolutePath(str));
+  return true;
+}
+
+static bool ospath_join(JSContext* cx, unsigned argc, Value* vp) {
+  CallArgs args = CallArgsFromVp(argc, vp);
+
+  if (args.length() < 1) {
+    JS_ReportErrorNumberASCII(cx, my_GetErrorMessage, nullptr,
+                              JSSMSG_INVALID_ARGS, "join");
+    return false;
+  }
+
+  // This function doesn't take into account some aspects of Windows paths,
+  // e.g. the drive letter is always reset when an absolute path is appended.
+
+  JSStringBuilder buffer(cx);
+  Rooted<JSLinearString*> str(cx);
+
+  for (unsigned i = 0; i < args.length(); i++) {
+    if (!args[i].isString()) {
+      JS_ReportErrorASCII(cx, "join expects string arguments only");
+      return false;
+    }
+
+    str = JS_EnsureLinearString(cx, args[i].toString());
+    if (!str) {
+      return false;
+    }
+
+    if (IsAbsolutePath(str)) {
+      MOZ_ALWAYS_TRUE(buffer.resize(0));
+    } else if (i != 0) {
+      UniqueChars path = JS_EncodeStringToUTF8(cx, str);
+      if (!path) {
+        return false;
+      }
+
+      if (!buffer.append(PathSeparator)) {
+        return false;
+      }
+    }
+
+    if (!buffer.append(args[i].toString())) {
+      return false;
+    }
+  }
+
+  JSString* result = buffer.finishString();
+  if (!result) {
+    return false;
+  }
+
+  args.rval().setString(result);
+  return true;
+}
+
+// clang-format off
+static const JSFunctionSpecWithHelp ospath_functions[] = {
+    JS_FN_HELP("isAbsolute", ospath_isAbsolute, 1, 0,
+"isAbsolute(path)",
+"  Return whether the given path is absolute."),
+
+    JS_FN_HELP("join", ospath_join, 1, 0,
+"join(paths...)",
+"  Join one or more path components in a platform independent way."),
+
+    JS_FS_HELP_END
+};
+// clang-format on
+
+static bool os_getenv(JSContext* cx, unsigned argc, Value* vp) {
+  CallArgs args = CallArgsFromVp(argc, vp);
+  if (args.length() < 1) {
+    JS_ReportErrorASCII(cx, "os.getenv requires 1 argument");
+    return false;
+  }
+  RootedString key(cx, ToString(cx, args[0]));
+  if (!key) {
+    return false;
+  }
+  UniqueChars keyBytes = JS_EncodeStringToUTF8(cx, key);
+  if (!keyBytes) {
+    return false;
+  }
+
+  if (const char* valueBytes = getenv(keyBytes.get())) {
+    RootedString value(cx, JS_NewStringCopyZ(cx, valueBytes));
+    if (!value) {
+      return false;
+    }
+    args.rval().setString(value);
+  } else {
+    args.rval().setUndefined();
+  }
+  return true;
+}
+
+static bool os_getpid(JSContext* cx, unsigned argc, Value* vp) {
+  CallArgs args = CallArgsFromVp(argc, vp);
+  if (args.length() != 0) {
+    JS_ReportErrorASCII(cx, "os.getpid takes no arguments");
+    return false;
+  }
+  args.rval().setInt32(getpid());
+  return true;
+}
+
+#if !defined(XP_WIN)
+
+// There are two possible definitions of strerror_r floating around. The GNU
+// one returns a char* which may or may not be the buffer you passed in. The
+// other one returns an integer status code, and always writes the result into
+// the provided buffer.
+
+inline char* strerror_message(int result, char* buffer) {
+  return result == 0 ? buffer : nullptr;
+}
+
+inline char* strerror_message(char* result, char* buffer) { return result; }
+
+#endif
+
+UniqueChars SystemErrorMessage(JSContext* cx, int errnum) {
+#if defined(XP_WIN)
+  wchar_t buffer[200];
+  const wchar_t* errstr = buffer;
+  if (_wcserror_s(buffer, mozilla::ArrayLength(buffer), errnum) != 0) {
+    errstr = L"unknown error";
+  }
+  return JS::EncodeWideToUtf8(cx, errstr);
+#else
+  char buffer[200];
+  const char* errstr = strerror_message(
+      strerror_r(errno, buffer, mozilla::ArrayLength(buffer)), buffer);
+  if (!errstr) {
+    errstr = "unknown error";
+  }
+  return JS::EncodeNarrowToUtf8(cx, errstr);
+#endif
+}
+
+#ifndef __wasi__
+static void ReportSysError(JSContext* cx, const char* prefix) {
+  MOZ_ASSERT(JS::StringIsASCII(prefix));
+
+  if (UniqueChars error = SystemErrorMessage(cx, errno)) {
+    JS_ReportErrorUTF8(cx, "%s: %s", prefix, error.get());
+  }
+}
+
+static bool os_system(JSContext* cx, unsigned argc, Value* vp) {
+  CallArgs args = CallArgsFromVp(argc, vp);
+
+  if (args.length() == 0) {
+    JS_ReportErrorASCII(cx, "os.system requires 1 argument");
+    return false;
+  }
+
+  Rooted<JSString*> str(cx, JS::ToString(cx, args[0]));
+  if (!str) {
+    return false;
+  }
+
+  UniqueChars command = JS_EncodeStringToUTF8(cx, str);
+  if (!command) {
+    return false;
+  }
+
+#  ifdef XP_WIN
+  UniqueWideChars wideCommand = JS::EncodeUtf8ToWide(cx, command.get());
+  if (!wideCommand) {
+    return false;
+  }
+
+  // Existing streams must be explicitly flushed or closed before calling
+  // the system() function on Windows.
+  _flushall();
+
+  int result = _wsystem(wideCommand.get());
+#  else
+  UniqueChars narrowCommand = JS::EncodeUtf8ToNarrow(cx, command.get());
+  if (!narrowCommand) {
+    return false;
+  }
+
+  int result = system(narrowCommand.get());
+#  endif
+  if (result == -1) {
+    ReportSysError(cx, "system call failed");
+    return false;
+  }
+
+  args.rval().setInt32(result);
+  return true;
+}
+
+#  ifndef XP_WIN
+static bool os_spawn(JSContext* cx, unsigned argc, Value* vp) {
+  CallArgs args = CallArgsFromVp(argc, vp);
+
+  if (args.length() == 0) {
+    JS_ReportErrorASCII(cx, "os.spawn requires 1 argument");
+    return false;
+  }
+
+  Rooted<JSString*> str(cx, JS::ToString(cx, args[0]));
+  if (!str) {
+    return false;
+  }
+
+  UniqueChars command = JS_EncodeStringToUTF8(cx, str);
+  if (!command) {
+    return false;
+  }
+  UniqueChars narrowCommand = JS::EncodeUtf8ToNarrow(cx, command.get());
+  if (!narrowCommand) {
+    return false;
+  }
+
+  int32_t childPid = fork();
+  if (childPid == -1) {
+    ReportSysError(cx, "fork failed");
+    return false;
+  }
+
+  if (childPid) {
+    args.rval().setInt32(childPid);
+    return true;
+  }
+
+  // We are in the child
+
+  const char* cmd[] = {"sh", "-c", nullptr, nullptr};
+  cmd[2] = narrowCommand.get();
+
+  execvp("sh", (char* const*)cmd);
+  exit(1);
+}
+
+static bool os_kill(JSContext* cx, unsigned argc, Value* vp) {
+  CallArgs args = CallArgsFromVp(argc, vp);
+  int32_t pid;
+  if (args.length() < 1) {
+    JS_ReportErrorASCII(cx, "os.kill requires 1 argument");
+    return false;
+  }
+  if (!JS::ToInt32(cx, args[0], &pid)) {
+    return false;
+  }
+
+  // It is too easy to kill yourself accidentally with os.kill("goose").
+  if (pid == 0 && !args[0].isInt32()) {
+    JS_ReportErrorASCII(cx, "os.kill requires numeric pid");
+    return false;
+  }
+
+  int signal = SIGINT;
+  if (args.length() > 1) {
+    if (!JS::ToInt32(cx, args[1], &signal)) {
+      return false;
+    }
+  }
+
+  int status = kill(pid, signal);
+  if (status == -1) {
+    ReportSysError(cx, "kill failed");
+    return false;
+  }
+
+  args.rval().setUndefined();
+  return true;
+}
+
+static bool os_waitpid(JSContext* cx, unsigned argc, Value* vp) {
+  CallArgs args = CallArgsFromVp(argc, vp);
+
+  int32_t pid;
+  if (args.length() == 0) {
+    pid = -1;
+  } else {
+    if (!JS::ToInt32(cx, args[0], &pid)) {
+      return false;
+    }
+  }
+
+  bool nohang = false;
+  if (args.length() >= 2) {
+    nohang = JS::ToBoolean(args[1]);
+  }
+
+  int status = 0;
+  pid_t result = waitpid(pid, &status, nohang ? WNOHANG : 0);
+  if (result == -1) {
+    ReportSysError(cx, "os.waitpid failed");
+    return false;
+  }
+
+  RootedObject info(cx, JS_NewPlainObject(cx));
+  if (!info) {
+    return false;
+  }
+
+  RootedValue v(cx);
+  if (result != 0) {
+    v.setInt32(result);
+    if (!JS_DefineProperty(cx, info, "pid", v, JSPROP_ENUMERATE)) {
+      return false;
+    }
+    if (WIFEXITED(status)) {
+      v.setInt32(WEXITSTATUS(status));
+      if (!JS_DefineProperty(cx, info, "exitStatus", v, JSPROP_ENUMERATE)) {
+        return false;
+      }
+    }
+  }
+
+  args.rval().setObject(*info);
+  return true;
+}
+#  endif
+#endif  // !__wasi__
+
+// clang-format off
+static const JSFunctionSpecWithHelp os_functions[] = {
+    JS_FN_HELP("getenv", os_getenv, 1, 0,
+"getenv(variable)",
+"  Get the value of an environment variable."),
+
+    JS_FN_HELP("getpid", os_getpid, 0, 0,
+"getpid()",
+"  Return the current process id."),
+
+#ifndef __wasi__
+    JS_FN_HELP("system", os_system, 1, 0,
+"system(command)",
+"  Execute command on the current host, returning result code or throwing an\n"
+"  exception on failure."),
+
+#  ifndef XP_WIN
+    JS_FN_HELP("spawn", os_spawn, 1, 0,
+"spawn(command)",
+"  Start up a separate process running the given command. Returns the pid."),
+
+    JS_FN_HELP("kill", os_kill, 1, 0,
+"kill(pid[, signal])",
+"  Send a signal to the given pid. The default signal is SIGINT. The signal\n"
+"  passed in must be numeric, if given."),
+
+    JS_FN_HELP("waitpid", os_waitpid, 1, 0,
+"waitpid(pid[, nohang])",
+"  Calls waitpid(). 'nohang' is a boolean indicating whether to pass WNOHANG.\n"
+"  The return value is an object containing a 'pid' field, if a process was waitable\n"
+"  and an 'exitStatus' field if a pid exited."),
+#  endif
+#endif  // !__wasi__
+
+    JS_FS_HELP_END
+};
+// clang-format on
+
+bool DefineOS(JSContext* cx, HandleObject global, bool fuzzingSafe,
+              RCFile** shellOut, RCFile** shellErr) {
+  RootedObject obj(cx, JS_NewPlainObject(cx));
+  if (!obj || !JS_DefineProperty(cx, global, "os", obj, 0)) {
+    return false;
+  }
+
+  if (!fuzzingSafe) {
+    if (!JS_DefineFunctionsWithHelp(cx, obj, os_functions)) {
+      return false;
+    }
+  }
+
+  RootedObject osfile(cx, JS_NewPlainObject(cx));
+  if (!osfile || !JS_DefineFunctionsWithHelp(cx, osfile, osfile_functions) ||
+      !JS_DefineProperty(cx, obj, "file", osfile, 0)) {
+    return false;
+  }
+
+  if (!fuzzingSafe) {
+    if (!JS_DefineFunctionsWithHelp(cx, osfile, osfile_unsafe_functions)) {
+      return false;
+    }
+  }
+
+  if (!GenerateInterfaceHelp(cx, osfile, "os.file")) {
+    return false;
+  }
+
+  RootedObject ospath(cx, JS_NewPlainObject(cx));
+  if (!ospath || !JS_DefineFunctionsWithHelp(cx, ospath, ospath_functions) ||
+      !JS_DefineProperty(cx, obj, "path", ospath, 0) ||
+      !GenerateInterfaceHelp(cx, ospath, "os.path")) {
+    return false;
+  }
+
+  if (!GenerateInterfaceHelp(cx, obj, "os")) {
+    return false;
+  }
+
+  ShellContext* scx = GetShellContext(cx);
+  scx->outFilePtr = shellOut;
+  scx->errFilePtr = shellErr;
+
+  // For backwards compatibility, expose various os.file.* functions as
+  // direct methods on the global.
+  struct Export {
+    const char* src;
+    const char* dst;
+  };
+
+  const Export osfile_exports[] = {
+      {"readFile", "read"},
+      {"readFile", "snarf"},
+      {"readRelativeToScript", "readRelativeToScript"},
+  };
+
+  for (auto pair : osfile_exports) {
+    if (!CreateAlias(cx, pair.dst, osfile, pair.src)) {
+      return false;
+    }
+  }
+
+  if (!fuzzingSafe) {
+    const Export unsafe_osfile_exports[] = {{"redirect", "redirect"},
+                                            {"redirectErr", "redirectErr"}};
+
+    for (auto pair : unsafe_osfile_exports) {
+      if (!CreateAlias(cx, pair.dst, osfile, pair.src)) {
+        return false;
+      }
+    }
+  }
+
+  return true;
+}
+
+}  // namespace shell
+}  // namespace js