1  /* Implementation of the _dl_write function.  Generic version.
       2     Copyright (C) 2020-2023 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 <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  }