Plumb sandbox rules through the helper executable.

chrome/app/chrome_exe_main_mac.c

-// Copyright 2015 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-// The entry point for all Mac Chromium processes, including the outer app
-// bundle (browser) and helper app (renderer, plugin, and friends).
-
-#include <dlfcn.h>
-#include <errno.h>
-#include <libgen.h>
-#include <mach-o/dyld.h>
-#include <stddef.h>
-#include <stdint.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <unistd.h>
-
-#include "chrome/common/chrome_version.h"
-
-typedef int (*ChromeMainPtr)(int, char**);
-
-__attribute__((visibility("default"))) int main(int argc, char* argv[]) {
-#if defined(HELPER_EXECUTABLE)
-  const char* const rel_path =
-      "../../../" PRODUCT_FULLNAME_STRING
-      " Framework.framework/" PRODUCT_FULLNAME_STRING " Framework";
-#else
-  const char* const rel_path =
-      "../Versions/" CHROME_VERSION_STRING "/" PRODUCT_FULLNAME_STRING
-      " Framework.framework/" PRODUCT_FULLNAME_STRING " Framework";
-#endif  // defined(HELPER_EXECUTABLE)
-
-  uint32_t exec_path_size = 0;
-  int rv = _NSGetExecutablePath(NULL, &exec_path_size);
-  if (rv != -1) {
-    fprintf(stderr, "_NSGetExecutablePath: get length failed\n");
-    abort();
-  }
-
-  char* exec_path = malloc(exec_path_size);
-  if (!exec_path) {
-    fprintf(stderr, "malloc %u: %s\n", exec_path_size, strerror(errno));
-    abort();
-  }
-
-  rv = _NSGetExecutablePath(exec_path, &exec_path_size);
-  if (rv != 0) {
-    fprintf(stderr, "_NSGetExecutablePath: get path failed\n");
-    abort();
-  }
-
-  // Slice off the last part of the main executable path, and append the
-  // version framework information.
-  const char* parent_dir = dirname(exec_path);
-  if (!parent_dir) {
-    fprintf(stderr, "dirname %s: %s\n", exec_path, strerror(errno));
-    abort();
-  }
-  free(exec_path);
-
-  const size_t parent_path_len = strlen(parent_dir);
-  const size_t rel_path_len = strlen(rel_path);
-  // 2 accounts for a trailing NUL byte and the '/' in the middle of the paths.
-  const size_t framework_path_size = parent_path_len + rel_path_len + 2;
-  char* framework_path = malloc(framework_path_size);
-  if (!framework_path) {
-    fprintf(stderr, "malloc %zu: %s\n", framework_path_size, strerror(errno));
-    abort();
-  }
-  snprintf(framework_path, framework_path_size, "%s/%s", parent_dir, rel_path);
-
-  void* library = dlopen(framework_path, RTLD_LAZY | RTLD_LOCAL | RTLD_FIRST);
-  if (!library) {
-    fprintf(stderr, "dlopen %s: %s\n", framework_path, dlerror());
-    abort();
-  }
-  free(framework_path);
-
-  const ChromeMainPtr chrome_main = dlsym(library, "ChromeMain");
-  if (!chrome_main) {
-    fprintf(stderr, "dlsym ChromeMain: %s\n", dlerror());
-    abort();
-  }
-  rv = chrome_main(argc, argv);
-
-  // exit, don't return from main, to avoid the apparent removal of main from
-  // stack backtraces under tail call optimization.
-  exit(rv);
-}