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libuv/src/unix/fs.c  view on Meta::CPAN

    for (nwritten = 0; nwritten < nread; ) {
      do
        n = write(out_fd, buf + nwritten, nread - nwritten);
      while (n == -1 && errno == EINTR);

      if (n != -1) {
        nwritten += n;
        continue;
      }

      if (errno != EAGAIN && errno != EWOULDBLOCK) {
        nsent = -1;
        goto out;
      }

      pfd.fd = out_fd;
      pfd.events = POLLOUT;
      pfd.revents = 0;

      do
        n = poll(&pfd, 1, -1);
      while (n == -1 && errno == EINTR);

      if (n == -1 || (pfd.revents & ~POLLOUT) != 0) {
        errno = EIO;
        nsent = -1;
        goto out;
      }
    }

    offset += nread;
    nsent += nread;
  }

out:
  if (nsent != -1)
    req->off = offset;

  return nsent;
}


static ssize_t uv__fs_sendfile(uv_fs_t* req) {
  int in_fd;
  int out_fd;

  in_fd = req->flags;
  out_fd = req->file;

#if defined(__linux__) || defined(__sun)
  {
    off_t off;
    ssize_t r;

    off = req->off;
    r = sendfile(out_fd, in_fd, &off, req->bufsml[0].len);

    /* sendfile() on SunOS returns EINVAL if the target fd is not a socket but
     * it still writes out data. Fortunately, we can detect it by checking if
     * the offset has been updated.
     */
    if (r != -1 || off > req->off) {
      r = off - req->off;
      req->off = off;
      return r;
    }

    if (errno == EINVAL ||
        errno == EIO ||
        errno == ENOTSOCK ||
        errno == EXDEV) {
      errno = 0;
      return uv__fs_sendfile_emul(req);
    }

    return -1;
  }
#elif defined(__APPLE__)           || \
      defined(__DragonFly__)       || \
      defined(__FreeBSD__)         || \
      defined(__FreeBSD_kernel__)
  {
    off_t len;
    ssize_t r;

    /* sendfile() on FreeBSD and Darwin returns EAGAIN if the target fd is in
     * non-blocking mode and not all data could be written. If a non-zero
     * number of bytes have been sent, we don't consider it an error.
     */

#if defined(__FreeBSD__) || defined(__DragonFly__)
    len = 0;
    r = sendfile(in_fd, out_fd, req->off, req->bufsml[0].len, NULL, &len, 0);
#elif defined(__FreeBSD_kernel__)
    len = 0;
    r = bsd_sendfile(in_fd,
                     out_fd,
                     req->off,
                     req->bufsml[0].len,
                     NULL,
                     &len,
                     0);
#else
    /* The darwin sendfile takes len as an input for the length to send,
     * so make sure to initialize it with the caller's value. */
    len = req->bufsml[0].len;
    r = sendfile(in_fd, out_fd, req->off, &len, NULL, 0);
#endif

     /*
     * The man page for sendfile(2) on DragonFly states that `len` contains
     * a meaningful value ONLY in case of EAGAIN and EINTR.
     * Nothing is said about it's value in case of other errors, so better
     * not depend on the potential wrong assumption that is was not modified
     * by the syscall.
     */
    if (r == 0 || ((errno == EAGAIN || errno == EINTR) && len != 0)) {
      req->off += len;
      return (ssize_t) len;
    }