view release on metacpan or  search on metacpan

libuv/src/win/process-stdio.c  view on Meta::CPAN

 * The `child_stdio_buffer` buffer has the following layout:
 *   int number_of_fds
 *   unsigned char crt_flags[number_of_fds]
 *   HANDLE os_handle[number_of_fds]
 */
#define CHILD_STDIO_SIZE(count)                     \
    (sizeof(int) +                                  \
     sizeof(unsigned char) * (count) +              \
     sizeof(uintptr_t) * (count))

#define CHILD_STDIO_COUNT(buffer)                   \
    *((unsigned int*) (buffer))

#define CHILD_STDIO_CRT_FLAGS(buffer, fd)           \
    *((unsigned char*) (buffer) + sizeof(int) + fd)

#define CHILD_STDIO_HANDLE(buffer, fd)              \
    *((HANDLE*) ((unsigned char*) (buffer) +        \
                 sizeof(int) +                      \
                 sizeof(unsigned char) *            \
                 CHILD_STDIO_COUNT((buffer)) +      \
                 sizeof(HANDLE) * (fd)))


/* CRT file descriptor mode flags */
#define FOPEN       0x01
#define FEOFLAG     0x02
#define FCRLF       0x04
#define FPIPE       0x08
#define FNOINHERIT  0x10
#define FAPPEND     0x20
#define FDEV        0x40
#define FTEXT       0x80


/*
 * Clear the HANDLE_FLAG_INHERIT flag from all HANDLEs that were inherited
 * the parent process. Don't check for errors - the stdio handles may not be
 * valid, or may be closed already. There is no guarantee that this function
 * does a perfect job.
 */
void uv_disable_stdio_inheritance(void) {
  HANDLE handle;
  STARTUPINFOW si;

  /* Make the windows stdio handles non-inheritable. */
  handle = GetStdHandle(STD_INPUT_HANDLE);
  if (handle != NULL && handle != INVALID_HANDLE_VALUE)
    SetHandleInformation(handle, HANDLE_FLAG_INHERIT, 0);

  handle = GetStdHandle(STD_OUTPUT_HANDLE);
  if (handle != NULL && handle != INVALID_HANDLE_VALUE)
    SetHandleInformation(handle, HANDLE_FLAG_INHERIT, 0);

  handle = GetStdHandle(STD_ERROR_HANDLE);
  if (handle != NULL && handle != INVALID_HANDLE_VALUE)
    SetHandleInformation(handle, HANDLE_FLAG_INHERIT, 0);

  /* Make inherited CRT FDs non-inheritable. */
  GetStartupInfoW(&si);
  if (uv__stdio_verify(si.lpReserved2, si.cbReserved2))
    uv__stdio_noinherit(si.lpReserved2);
}


static int uv__create_stdio_pipe_pair(uv_loop_t* loop,
    uv_pipe_t* server_pipe, HANDLE* child_pipe_ptr, unsigned int flags) {
  char pipe_name[64];
  SECURITY_ATTRIBUTES sa;
  DWORD server_access = 0;
  DWORD client_access = 0;
  HANDLE child_pipe = INVALID_HANDLE_VALUE;
  int err;
  int overlap;

  if (flags & UV_READABLE_PIPE) {
    /* The server needs inbound access too, otherwise CreateNamedPipe() won't
     * give us the FILE_READ_ATTRIBUTES permission. We need that to probe the
     * state of the write buffer when we're trying to shutdown the pipe. */
    server_access |= PIPE_ACCESS_OUTBOUND | PIPE_ACCESS_INBOUND;
    client_access |= GENERIC_READ | FILE_WRITE_ATTRIBUTES;
  }
  if (flags & UV_WRITABLE_PIPE) {
    server_access |= PIPE_ACCESS_INBOUND;
    client_access |= GENERIC_WRITE | FILE_READ_ATTRIBUTES;
  }

  /* Create server pipe handle. */
  err = uv_stdio_pipe_server(loop,
                             server_pipe,
                             server_access,
                             pipe_name,
                             sizeof(pipe_name));
  if (err)
    goto error;

  /* Create child pipe handle. */
  sa.nLength = sizeof sa;
  sa.lpSecurityDescriptor = NULL;
  sa.bInheritHandle = TRUE;

  overlap = server_pipe->ipc || (flags & UV_OVERLAPPED_PIPE);
  child_pipe = CreateFileA(pipe_name,
                           client_access,
                           0,
                           &sa,
                           OPEN_EXISTING,
                           overlap ? FILE_FLAG_OVERLAPPED : 0,
                           NULL);
  if (child_pipe == INVALID_HANDLE_VALUE) {
    err = GetLastError();
    goto error;
  }

#ifndef NDEBUG
  /* Validate that the pipe was opened in the right mode. */
  {
    DWORD mode;
    BOOL r = GetNamedPipeHandleState(child_pipe,
                                     &mode,
                                     NULL,

libuv/src/win/process-stdio.c  view on Meta::CPAN

            stream_handle == INVALID_HANDLE_VALUE) {
          /* The handle is already closed, or not yet created, or the stream
           * type is not supported. */
          err = ERROR_NOT_SUPPORTED;
          goto error;
        }

        /* Make an inheritable copy of the handle. */
        err = uv__duplicate_handle(loop, stream_handle, &child_handle);
        if (err)
          goto error;

        CHILD_STDIO_HANDLE(buffer, i) = child_handle;
        CHILD_STDIO_CRT_FLAGS(buffer, i) = crt_flags;
        break;
      }

      default:
        assert(0);
        return -1;
    }
  }

  *buffer_ptr  = buffer;
  return 0;

 error:
  uv__stdio_destroy(buffer);
  return err;
}


void uv__stdio_destroy(BYTE* buffer) {
  int i, count;

  count = CHILD_STDIO_COUNT(buffer);
  for (i = 0; i < count; i++) {
    HANDLE handle = CHILD_STDIO_HANDLE(buffer, i);
    if (handle != INVALID_HANDLE_VALUE) {
      CloseHandle(handle);
    }
  }

  uv__free(buffer);
}


void uv__stdio_noinherit(BYTE* buffer) {
  int i, count;

  count = CHILD_STDIO_COUNT(buffer);
  for (i = 0; i < count; i++) {
    HANDLE handle = CHILD_STDIO_HANDLE(buffer, i);
    if (handle != INVALID_HANDLE_VALUE) {
      SetHandleInformation(handle, HANDLE_FLAG_INHERIT, 0);
    }
  }
}


int uv__stdio_verify(BYTE* buffer, WORD size) {
  unsigned int count;

  /* Check the buffer pointer. */
  if (buffer == NULL)
    return 0;

  /* Verify that the buffer is at least big enough to hold the count. */
  if (size < CHILD_STDIO_SIZE(0))
    return 0;

  /* Verify if the count is within range. */
  count = CHILD_STDIO_COUNT(buffer);
  if (count > 256)
    return 0;

  /* Verify that the buffer size is big enough to hold info for N FDs. */
  if (size < CHILD_STDIO_SIZE(count))
    return 0;

  return 1;
}


WORD uv__stdio_size(BYTE* buffer) {
  return (WORD) CHILD_STDIO_SIZE(CHILD_STDIO_COUNT((buffer)));
}


HANDLE uv__stdio_handle(BYTE* buffer, int fd) {
  return CHILD_STDIO_HANDLE(buffer, fd);
}