The generic version is parallel to _dl_writev. It cannot use
_dl_writev directly because the errno value needs to be obtained
under a lock.
---
elf/Makefile | 2 +-
elf/dl-write.c | 56 ++++++++++++++++++++++++++++++
sysdeps/generic/ldsodefs.h | 6 ++++
sysdeps/unix/sysv/linux/dl-write.c | 30 ++++++++++++++++
4 files changed, 93 insertions(+), 1 deletion(-)
create mode 100644 elf/dl-write.c
create mode 100644 sysdeps/unix/sysv/linux/dl-write.c
@@ -34,7 +34,7 @@ dl-routines = $(addprefix dl-,load lookup object reloc deps \
version profile tls origin scope \
execstack open close trampoline \
exception sort-maps lookup-direct \
- call-libc-early-init)
+ call-libc-early-init write)
ifeq (yes,$(use-ldconfig))
dl-routines += dl-cache
endif
new file mode 100644
@@ -0,0 +1,56 @@
+/* Implementation of the _dl_write function. Generic version.
+ Copyright (C) 2020 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));
+ __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;
+}
@@ -749,6 +749,12 @@ _dl_dprintf (int fd, const char *fmt, ...)
}
#endif
+/* Write LENGTH bytes at BUFFER to FD, like write. Returns the number
+ of bytes written on success, or a negative error constant on
+ failure. */
+ssize_t _dl_write (int fd, const void *buffer, size_t length)
+ attribute_hidden;
+
/* Write a message on the specified descriptor standard output. The
parameters are interpreted as for a `printf' call. */
void _dl_printf (const char *fmt, ...)
new file mode 100644
@@ -0,0 +1,30 @@
+/* Implementation of the _dl_write function. Linux version.
+ Copyright (C) 2020 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 <sysdep.h>
+#include <unistd.h>
+#include <ldsodefs.h>
+
+ssize_t
+_dl_write (int fd, const void *buffer, size_t length)
+{
+ long int r = INTERNAL_SYSCALL_CALL (write, fd, buffer, length);
+ if (INTERNAL_SYSCALL_ERROR_P (r))
+ r = - INTERNAL_SYSCALL_ERRNO (r);
+ return r;
+}