sysdeps/unix/sysv/linux/pwritev64v2.c

   1 /* Linux implementation of pwritev2 (LFS version).
   2    Copyright (C) 2017-2024 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/uio.h>
  20 #include <sysdep-cancel.h>
  21
  22 ssize_t
  23 pwritev64v2 (int fd, const struct iovec *vector, int count, off64_t offset,
  24              int flags)
  25 {
  26   ssize_t result = SYSCALL_CANCEL (pwritev2, fd, vector, count,
  27                                    LO_HI_LONG (offset), flags);
  28   if (result >= 0 || errno != ENOSYS)
  29     return result;
  30
  31   /* Trying to emulate the pwritev2 syscall flags is troublesome:
  32
  33      * We can not temporary change the file state of the O_DSYNC and O_SYNC
  34        flags to emulate RWF_{D}SYNC (attempts to change the state of using
  35        fcntl are silently ignored).
  36
  37      * IOCB_HIPRI requires the file opened in O_DIRECT and uses an internal
  38        semantic not provided by any other flag (O_NONBLOCK for instance).  */
  39
  40   if (flags != 0)
  41     {
  42       __set_errno (ENOTSUP);
  43       return -1;
  44     }
  45   if (offset == -1)
  46     return __writev (fd, vector, count);
  47   else
  48     return pwritev64 (fd, vector, count, offset);
  49 }
  50
  51 #ifdef __OFF_T_MATCHES_OFF64_T
  52 strong_alias (pwritev64v2, pwritev2)
  53 #endif