Adds USB writing for OS X.

chrome/utility/image_writer/image_writer_mac.cc

+// Copyright 2014 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.
+
+#include <IOKit/storage/IOStorageProtocolCharacteristics.h>
+#include <sys/socket.h>
+
+#include "base/command_line.h"
+#include "base/files/scoped_file.h"
+#include "base/posix/eintr_wrapper.h"
+#include "base/process/kill.h"
+#include "base/process/launch.h"
+#include "base/strings/stringprintf.h"
+#include "chrome/utility/image_writer/disk_unmounter_mac.h"
+#include "chrome/utility/image_writer/error_messages.h"
+#include "chrome/utility/image_writer/image_writer.h"
+
+namespace image_writer {
+
+static const char kAuthOpenPath[] = "/usr/libexec/authopen";
+
+bool ImageWriter::IsValidDevice() {
+  base::ScopedCFTypeRef<DASessionRef> session(DASessionCreate(NULL));
+  base::ScopedCFTypeRef<DADiskRef> disk(DADiskCreateFromBSDName(
+      kCFAllocatorDefault, session, device_path_.value().c_str()));
+
+  if (!disk)
+    return false;
+
+  base::ScopedCFTypeRef<CFDictionaryRef> disk_description(
+      DADiskCopyDescription(disk));
+
+  CFBooleanRef ejectable = base::mac::GetValueFromDictionary<CFBooleanRef>(
+      disk_description, kDADiskDescriptionMediaEjectableKey);
+  CFBooleanRef removable = base::mac::GetValueFromDictionary<CFBooleanRef>(
+      disk_description, kDADiskDescriptionMediaRemovableKey);
+  CFBooleanRef writable = base::mac::GetValueFromDictionary<CFBooleanRef>(
+      disk_description, kDADiskDescriptionMediaWritableKey);
+  CFBooleanRef whole = base::mac::GetValueFromDictionary<CFBooleanRef>(
+      disk_description, kDADiskDescriptionMediaWholeKey);
+  CFStringRef kind = base::mac::GetValueFromDictionary<CFStringRef>(
+      disk_description, kDADiskDescriptionMediaKindKey);
+
+  // A drive is valid if it is
+  // - ejectable
+  // - removable
+  // - writable
+  // - a whole drive
+  // - it is of type IOMedia (external DVD drives and the like are IOCDMedia or
+  //   IODVDMedia)
+  return CFBooleanGetValue(ejectable) && CFBooleanGetValue(removable) &&
+         CFBooleanGetValue(writable) && CFBooleanGetValue(whole) &&
+         CFStringCompare(kind, CFSTR("IOMedia"), 0) == kCFCompareEqualTo;
+}
+
+void ImageWriter::UnmountVolumes(const base::Closure& continuation) {
+  if (unmounter_ == NULL) {
+    unmounter_.reset(new DiskUnmounterMac());
+  }
+
+  unmounter_->Unmount(
+      device_path_.value(),
+      continuation,
+      base::Bind(
+          &ImageWriter::Error, base::Unretained(this), error::kUnmountVolumes));
+}
+
+bool ImageWriter::OpenDevice() {
+  base::LaunchOptions options = base::LaunchOptions();
+  options.wait = false;
+
+  // Create a socket pair for communication.
+  int sockets[2];
+  int result = socketpair(AF_UNIX, SOCK_STREAM, 0, sockets);
+  if (result == -1) {
+    PLOG(ERROR) << "Unable to allocate socket pair.";
+    return false;
+  }
+  base::ScopedFD parent_socket(sockets[0]);
+  base::ScopedFD child_socket(sockets[1]);
+
+  // Map the client socket to the client's STDOUT.
+  base::FileHandleMappingVector fd_map;
+  fd_map.push_back(std::pair<int, int>(child_socket.get(), STDOUT_FILENO));
+  options.fds_to_remap = &fd_map;
+
+  // Find the file path to open.
+  base::FilePath real_device_path;
+  if (device_path_.IsAbsolute()) {
+    real_device_path = device_path_;
+  } else {
+    real_device_path = base::FilePath("/dev").Append(device_path_);
+  }
+
+  // Build the command line.
+  std::string rdwr = base::StringPrintf("%d", O_RDWR);
+
+  base::CommandLine cmd_line = base::CommandLine(base::FilePath(kAuthOpenPath));
+  cmd_line.AppendSwitch("-stdoutpipe");
+  // Using AppendSwitchNative will use an equal-symbol which we don't want.
+  cmd_line.AppendArg("-o");
+  cmd_line.AppendArg(rdwr);
+  cmd_line.AppendArgPath(real_device_path);
+
+  // Launch the process.
+  base::ProcessHandle process_handle;
+  if (!base::LaunchProcess(cmd_line, options, &process_handle)) {
+    LOG(ERROR) << "Failed to launch authopen process.";
+    return false;
+  }
+
+  // Receive a file descriptor from authopen which sends a single FD via
+  // sendmsg and the SCM_RIGHTS extension.
+  int fd = -1;
+  const size_t kDataBufferSize = sizeof(struct cmsghdr) + sizeof(int);
+  char data_buffer[kDataBufferSize];
+
+  struct iovec io_vec[1];
+  io_vec[0].iov_base = data_buffer;
+  io_vec[0].iov_len = kDataBufferSize;
+
+  const socklen_t kCmsgSocketSize =
+      static_cast<socklen_t>(CMSG_SPACE(sizeof(int)));
+  char cmsg_socket[kCmsgSocketSize];
+
+  struct msghdr message = {0};
+  message.msg_iov = io_vec;
+  message.msg_iovlen = 1;
+  message.msg_control = cmsg_socket;
+  message.msg_controllen = kCmsgSocketSize;
+
+  ssize_t size = HANDLE_EINTR(recvmsg(parent_socket.get(), &message, 0));
+  if (size > 0) {
+    struct cmsghdr* cmsg_socket_header = CMSG_FIRSTHDR(&message);
+
+    if (cmsg_socket_header && cmsg_socket_header->cmsg_level == SOL_SOCKET &&
+        cmsg_socket_header->cmsg_type == SCM_RIGHTS)
+      fd = *reinterpret_cast<int*>(CMSG_DATA(cmsg_socket_header));

[Robert Sesek, 2014/06/16 22:15:21]

nit: braces needed around body since the condition spans more than one line

[Drew Haven, 2014/06/17 00:00:45]

Done.

+  }
+
+  device_file_ = base::File(fd);
+
+  // Wait for the child.
+  int child_exit_status;
+  if (!base::WaitForExitCode(process_handle, &child_exit_status)) {
+    LOG(ERROR) << "Unable to wait for child.";
+    return false;
+  }
+
+  if (child_exit_status) {
+    LOG(ERROR) << "Child process returned failure.";
+    return false;
+  }
+
+  return device_file_.IsValid();
+}
+
+}  // namespace image_writer