1  /* Transfer data between file descriptors.  Linux version.
       2     Copyright (C) 2011-2023 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library.
       4  
       5     The GNU C Library is free software; you can redistribute it and/or
       6     modify it under the terms of the GNU Lesser General Public
       7     License as published by the Free Software Foundation; either
       8     version 2.1 of the License, or (at your option) any later version.
       9  
      10     The GNU C Library is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      13     Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public
      16     License along with the GNU C Library.  If not, see
      17     <https://www.gnu.org/licenses/>.  */
      18  
      19  #include <sys/sendfile.h>
      20  #include <stddef.h>
      21  #include <errno.h>
      22  #include <sysdep.h>
      23  
      24  #ifndef __OFF_T_MATCHES_OFF64_T
      25  
      26  /* Send COUNT bytes from file associated with IN_FD starting at OFFSET to
      27     descriptor OUT_FD.  */
      28  ssize_t
      29  sendfile (int out_fd, int in_fd, off_t *offset, size_t count)
      30  {
      31  # ifdef __NR_sendfile
      32    return INLINE_SYSCALL_CALL (sendfile, out_fd, in_fd, offset, count);
      33  # else
      34    __off64_t off64;
      35    int rc;
      36  
      37    if (offset != NULL)
      38      {
      39        if (*offset < 0 || (off_t) (*offset + count) < 0)
      40          {
      41            __set_errno (EINVAL);
      42            return -1;
      43          }
      44        off64 = *offset;
      45      }
      46  
      47    rc = INLINE_SYSCALL_CALL (sendfile64, out_fd, in_fd, offset ? &off64 : NULL,
      48  			    count);
      49    if (offset)
      50      *offset = off64;
      51    return rc;
      52  # endif
      53  }
      54  
      55  #endif