elf/dl-write.c

   1 /* Implementation of the _dl_write function.  Generic version.
   2    Copyright (C) 2020-2022 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 <errno.h>
  20 #include <ldsodefs.h>
  21 #include <libc-lock.h>
  22 #include <sys/uio.h>
  23
  24 ssize_t
  25 _dl_write (int fd, const void *buffer, size_t length)
  26 {
  27   struct iovec iov = { .iov_base = (void *) buffer, .iov_len = length };
  28   ssize_t ret;
  29
  30 #if RTLD_PRIVATE_ERRNO
  31   /* We have to take this lock just to be sure we don't clobber the private
  32      errno when it's being used by another thread that cares about it.
  33      Yet we must be sure not to try calling the lock functions before
  34      the thread library is fully initialized.  */
  35   if (__glibc_unlikely (_dl_starting_up))
  36     {
  37       ret = __writev (fd, &iov, 1);
  38       if (ret < 0)
  39         ret = -errno;
  40     }
  41   else
  42     {
  43       __rtld_lock_lock_recursive (GL(dl_load_lock));
  44       ret = __writev (fd, &iov, 1);
  45       if (ret < 0)
  46         ret = -errno;
  47       __rtld_lock_unlock_recursive (GL(dl_load_lock));
  48     }
  49 #else
  50   ret = __writev (fd, &iov, 1);
  51   if (ret < 0)
  52     ret = -errno;
  53 #endif
  54
  55   return ret;
  56 }