| /* writev supports all Linux kernels >= 2.0. |
| Copyright (C) 1997-2014 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 |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include <errno.h> |
| #include <stddef.h> |
| #include <sys/param.h> |
| #include <sys/uio.h> |
| |
| #include <sysdep-cancel.h> |
| #include <sys/syscall.h> |
| #include <kernel-features.h> |
| |
| #ifndef __ASSUME_COMPLETE_READV_WRITEV |
| static ssize_t __atomic_writev_replacement (int, const struct iovec *, |
| int) internal_function; |
| #endif |
| |
| |
| /* Not all versions of the kernel support the large number of records. */ |
| #ifndef UIO_FASTIOV |
| # define UIO_FASTIOV 8 /* 8 is a safe number. */ |
| #endif |
| |
| |
| ssize_t |
| __libc_writev (fd, vector, count) |
| int fd; |
| const struct iovec *vector; |
| int count; |
| { |
| ssize_t result; |
| |
| if (SINGLE_THREAD_P) |
| result = INLINE_SYSCALL (writev, 3, fd, vector, count); |
| else |
| { |
| int oldtype = LIBC_CANCEL_ASYNC (); |
| |
| result = INLINE_SYSCALL (writev, 3, fd, vector, count); |
| |
| LIBC_CANCEL_RESET (oldtype); |
| } |
| |
| #ifdef __ASSUME_COMPLETE_READV_WRITEV |
| return result; |
| #else |
| if (result >= 0 || errno != EINVAL || count <= UIO_FASTIOV) |
| return result; |
| |
| return __atomic_writev_replacement (fd, vector, count); |
| #endif |
| } |
| strong_alias (__libc_writev, __writev) |
| weak_alias (__libc_writev, writev) |
| |
| #ifndef __ASSUME_COMPLETE_READV_WRITEV |
| # define __libc_writev static internal_function __atomic_writev_replacement |
| # include <sysdeps/posix/writev.c> |
| #endif |