libuv/src/win/process-stdio.c

/* Copyright Joyent, Inc. and other Node contributors. All rights reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
 * deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 */

#include <assert.h>
#include <io.h>
#include <stdio.h>
#include <stdlib.h>

#include "uv.h"
#include "internal.h"


/*
 * 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


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;

  if (flags & UV_READABLE_PIPE) {
    server_access |= PIPE_ACCESS_OUTBOUND;
    client_access |= GENERIC_READ | FILE_WRITE_ATTRIBUTES;
  }
  if (flags & UV_WRITABLE_PIPE) {
    server_access |= PIPE_ACCESS_INBOUND;
    client_access |= GENERIC_WRITE;
  }

  /* Create server pipe handle. */
  if (uv_stdio_pipe_server(loop,
                           server_pipe,
                           server_access,
                           pipe_name,
                           sizeof(pipe_name)) < 0) {
    goto error;
  }

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

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

#ifndef NDEBUG
  /* Validate that the pipe was opened in the right mode. */
  {
    DWORD mode;
    BOOL r = GetNamedPipeHandleState(child_pipe,
                                     &mode,
                                     NULL,
                                     NULL,
                                     NULL,
                                     NULL,
                                     0);
    assert(r == TRUE);
    assert(mode == (PIPE_READMODE_BYTE | PIPE_WAIT));
  }
#endif

  /* Do a blocking ConnectNamedPipe.  This should not block because we have */
  /* both ends of the pipe created. */
  if (!ConnectNamedPipe(server_pipe->handle, NULL)) {
    if (GetLastError() != ERROR_PIPE_CONNECTED) {
      uv__set_sys_error(loop, GetLastError());
      goto error;
    }
  }

  *child_pipe_ptr = child_pipe;
  return 0;

 error:
  if (server_pipe->handle != INVALID_HANDLE_VALUE) {
    uv_pipe_cleanup(loop, server_pipe);
  }

  if (child_pipe != INVALID_HANDLE_VALUE) {
    CloseHandle(child_pipe);
  }

  return -1;
}


static int uv__duplicate_handle(uv_loop_t* loop, HANDLE handle, HANDLE* dup) {
  HANDLE current_process;

  current_process = GetCurrentProcess();

  if (!DuplicateHandle(current_process,
                       handle,
                       current_process,
                       dup,
                       0,
                       TRUE,
                       DUPLICATE_SAME_ACCESS)) {
    *dup = INVALID_HANDLE_VALUE;
    uv__set_sys_error(loop, GetLastError());
    return -1;
  }

  return 0;
}


static int uv__duplicate_fd(uv_loop_t* loop, int fd, HANDLE* dup) {
  HANDLE handle;

  if (fd == -1) {
    *dup = INVALID_HANDLE_VALUE;
    uv__set_artificial_error(loop, UV_EBADF);
    return -1;
  }

  handle = (HANDLE)_get_osfhandle(fd);
  return uv__duplicate_handle(loop, handle, dup);
}


static int uv__create_nul_handle(uv_loop_t* loop, HANDLE* handle_ptr,
    DWORD access) {
  HANDLE handle;
  SECURITY_ATTRIBUTES sa;

  sa.nLength = sizeof sa;
  sa.lpSecurityDescriptor = NULL;
  sa.bInheritHandle = TRUE;

  handle = CreateFileW(L"NUL",
                       access,
                       FILE_SHARE_READ | FILE_SHARE_WRITE,
                       &sa,
                       OPEN_EXISTING,
                       0,
                       NULL);
  if (handle == INVALID_HANDLE_VALUE) {
    uv__set_sys_error(loop, GetLastError());
    return -1;
  }

  *handle_ptr = handle;
  return 0;
}


int uv__stdio_create(uv_loop_t* loop, uv_process_options_t* options,
    BYTE** buffer_ptr) {
  BYTE* buffer;
  int count, i;

  count = options->stdio_count;

  if (count < 0 || count > 255) {
    /* Only support FDs 0-255 */
    uv__set_artificial_error(loop, UV_ENOTSUP);
    return -1;
  } else if (count < 3) {
    /* There should always be at least 3 stdio handles. */
    count = 3;
  }

  /* Allocate the child stdio buffer */
  buffer = malloc(CHILD_STDIO_SIZE(count));
  if (buffer == NULL) {
    uv__set_artificial_error(loop, UV_ENOMEM);
    return -1;
  }

  /* Prepopulate the buffer with INVALID_HANDLE_VALUE handles so we can */
  /* clean up on failure. */
  CHILD_STDIO_COUNT(buffer) = count;
  for (i = 0; i < count; i++) {
    CHILD_STDIO_CRT_FLAGS(buffer, i) = 0;
    CHILD_STDIO_HANDLE(buffer, i) = INVALID_HANDLE_VALUE;
  }

  for (i = 0; i < count; i++) {
    uv_stdio_container_t fdopt;
    if (i < options->stdio_count) {
      fdopt = options->stdio[i];
    } else {
      fdopt.flags = UV_IGNORE;
    }

    switch (fdopt.flags & (UV_IGNORE | UV_CREATE_PIPE | UV_INHERIT_FD |
            UV_INHERIT_STREAM)) {
      case UV_IGNORE:
        /* Starting a process with no stdin/stout/stderr can confuse it. */
        /* So no matter what the user specified, we make sure the first */
        /* three FDs are always open in their typical modes, e.g. stdin */
        /* be readable and stdout/err should be writable. For FDs > 2, don't */
        /* do anything - all handles in the stdio buffer are initialized with */
        /* INVALID_HANDLE_VALUE, which should be okay. */
        if (i <= 2) {
          DWORD access = (i == 0) ? FILE_GENERIC_READ :
                                    FILE_GENERIC_WRITE | FILE_READ_ATTRIBUTES;
          if (uv__create_nul_handle(loop,
                                &CHILD_STDIO_HANDLE(buffer, i),
                                access) < 0) {
            goto error;
          }
          CHILD_STDIO_CRT_FLAGS(buffer, i) = FOPEN | FDEV;
        }
        break;

      case UV_CREATE_PIPE: {
        /* Create a pair of two connected pipe ends; one end is turned into */
        /* an uv_pipe_t for use by the parent. The other one is given to */
        /* the child. */
        uv_pipe_t* parent_pipe = (uv_pipe_t*) fdopt.data.stream;
        HANDLE child_pipe;

        /* Create a new, connected pipe pair. stdio[i].stream should point */
        /* to an uninitialized, but not connected pipe handle. */
        assert(fdopt.data.stream->type == UV_NAMED_PIPE);
        assert(!(fdopt.data.stream->flags & UV_HANDLE_CONNECTION));
        assert(!(fdopt.data.stream->flags & UV_HANDLE_PIPESERVER));

        if (uv__create_stdio_pipe_pair(loop,
                                      parent_pipe,
                                      &child_pipe,
                                      fdopt.flags) < 0) {
          goto error;
        }

        CHILD_STDIO_HANDLE(buffer, i) = child_pipe;
        CHILD_STDIO_CRT_FLAGS(buffer, i) = FOPEN | FPIPE;
        break;
      }

      case UV_INHERIT_FD: {
        /* Inherit a raw FD. */
        HANDLE child_handle;

        /* Make an inheritable duplicate of the handle. */
        if (uv__duplicate_fd(loop, fdopt.data.fd, &child_handle) < 0) {
          goto error;
        }

        /* Figure out what the type is. */
        switch (GetFileType(child_handle)) {
          case FILE_TYPE_DISK:
            CHILD_STDIO_CRT_FLAGS(buffer, i) = FOPEN;
            break;

          case FILE_TYPE_PIPE:
            CHILD_STDIO_CRT_FLAGS(buffer, i) = FOPEN | FPIPE;

          case FILE_TYPE_CHAR:
          case FILE_TYPE_REMOTE:
            CHILD_STDIO_CRT_FLAGS(buffer, i) = FOPEN | FDEV;
            break;

          case FILE_TYPE_UNKNOWN:
            if (GetLastError != 0) {
              uv__set_sys_error(loop, GetLastError());
              CloseHandle(child_handle);
              goto error;
            }
            CHILD_STDIO_CRT_FLAGS(buffer, i) = FOPEN | FDEV;
            break;

          default:
            assert(0);
        }

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

      case UV_INHERIT_STREAM: {
        /* Use an existing stream as the stdio handle for the child. */
        HANDLE stream_handle, child_handle;
        unsigned char crt_flags;
        uv_stream_t* stream = fdopt.data.stream;

        /* Leech the handle out of the stream. */
        if (stream->type == UV_TTY) {
          stream_handle = ((uv_tty_t*) stream)->handle;
          crt_flags = FOPEN | FDEV;
        } else if (stream->type == UV_NAMED_PIPE &&
                   stream->flags & UV_HANDLE_CONNECTED) {
          stream_handle = ((uv_pipe_t*) stream)->handle;
          crt_flags = FOPEN | FPIPE;
        } else {
          stream_handle = INVALID_HANDLE_VALUE;
          crt_flags = 0;
        }

        if (stream_handle == NULL ||
            stream_handle == INVALID_HANDLE_VALUE) {
          /* The handle is already closed, or not yet created, or the */
          /* stream type is not supported. */
          uv__set_artificial_error(loop, UV_ENOTSUP);
          goto error;
        }

        /* Make an inheritable copy of the handle. */
        if (uv__duplicate_handle(loop,
                             stream_handle,
                             &child_handle) < 0) {
          goto error;
        }

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

      default:
        assert(0);
    }
  }

  *buffer_ptr  = buffer;
  return 0;

 error:
  uv__stdio_destroy(buffer);
  return -1;
}


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);
    }
  }

  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);
    }
  }
}


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);
}