glibc/elf/dl-write.c

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/* Implementation of the _dl_write function. Generic version.
Copyright (C) 2020-2021 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <errno.h>
#include <ldsodefs.h>
#include <libc-lock.h>
#include <sys/uio.h>
ssize_t
_dl_write (int fd, const void *buffer, size_t length)
{
struct iovec iov = { .iov_base = (void *) buffer, .iov_len = length };
ssize_t ret;
#if RTLD_PRIVATE_ERRNO
/* We have to take this lock just to be sure we don't clobber the private
errno when it's being used by another thread that cares about it.
Yet we must be sure not to try calling the lock functions before
the thread library is fully initialized. */
if (__glibc_unlikely (_dl_starting_up))
{
ret = __writev (fd, &iov, 1);
if (ret < 0)
ret = -errno;
}
else
{
__rtld_lock_lock_recursive (GL(dl_load_lock));
ret = __writev (fd, &iov, 1);
if (ret < 0)
ret = -errno;
__rtld_lock_unlock_recursive (GL(dl_load_lock));
}
#else
ret = __writev (fd, &iov, 1);
if (ret < 0)
ret = -errno;
#endif
return ret;
}