sysdeps/unix/sysv/linux/sendfile.c

   1 /* Transfer data between file descriptors.  Linux version.
   2    Copyright (C) 2011-2024 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