sysdeps/nacl/dl-writev.h

   1 /* Message-writing for the dynamic linker.  NaCl version.
   2    Copyright (C) 2015 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    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <sys/uio.h>
  20 #include <nacl-interfaces.h>
  21
  22 /* This is used from only one place: dl-misc.c:_dl_debug_vdprintf.
  23    Hence it's in a header with the expectation it will be inlined.
  24
  25    This is writev, but with a constraint added and others loosened:
  26
  27    1. Under RTLD_PRIVATE_ERRNO, it must not clobber the private errno
  28       when another thread holds the dl_load_lock.
  29    2. It is not obliged to detect and report errors at all.
  30    3. It's not really obliged to deliver a single atomic write
  31       (though it may be preferable).  */
  32
  33 static inline void
  34 _dl_writev (int fd, const struct iovec *iov, size_t niov)
  35 {
  36   for (size_t i = 0; i < niov; ++i)
  37     {
  38       size_t wrote;
  39       if (__nacl_irt_fdio.write (fd, iov[i].iov_base, iov[i].iov_len,
  40                                  &wrote) != 0
  41           || wrote != iov[i].iov_len)
  42         /* The write failed, so don't bother trying any more.  */
  43         break;
  44     }
  45 }