mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-15 15:40:12 +00:00
99 lines
2.8 KiB
C
99 lines
2.8 KiB
C
/* Copyright (C) 1991, 1992, 1996, 1997, 2002 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, write to the Free
|
|
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
|
|
02111-1307 USA. */
|
|
|
|
#include <stdlib.h>
|
|
#include <unistd.h>
|
|
#include <string.h>
|
|
#include <limits.h>
|
|
#include <stdbool.h>
|
|
#include <sys/param.h>
|
|
#include <sys/uio.h>
|
|
|
|
/* Write data pointed by the buffers described by VECTOR, which
|
|
is a vector of COUNT `struct iovec's, to file descriptor FD.
|
|
The data is written in the order specified.
|
|
Operates just like `write' (see <unistd.h>) except that the data
|
|
are taken from VECTOR instead of a contiguous buffer. */
|
|
ssize_t
|
|
__writev (fd, vector, count)
|
|
int fd;
|
|
const struct iovec *vector;
|
|
int count;
|
|
{
|
|
char *buffer;
|
|
register char *bp;
|
|
size_t bytes, to_copy;
|
|
ssize_t bytes_written;
|
|
int i;
|
|
bool use_malloc = false;
|
|
|
|
/* Find the total number of bytes to be written. */
|
|
bytes = 0;
|
|
for (i = 0; i < count; ++i)
|
|
{
|
|
/* Check for ssize_t overflow. */
|
|
if (SSIZE_MAX - bytes < vector[i].iov_len)
|
|
{
|
|
errno = EINVAL;
|
|
return -1;
|
|
}
|
|
bytes += vector[i].iov_len;
|
|
}
|
|
|
|
/* Allocate a temporary buffer to hold the data. We should normally
|
|
use alloca since it's faster and does not require synchronization
|
|
with other threads. But we cannot if the amount of memory
|
|
required is too large. Use 512k as the limit. */
|
|
if (bytes < 512 * 1024)
|
|
buffer = (char *) __alloca (bytes);
|
|
else
|
|
{
|
|
buffer = (char *) malloc (bytes);
|
|
if (buffer == NULL)
|
|
/* XXX I don't know whether it is acceptable to try writing
|
|
the data in chunks. Probably not so we just fail here. */
|
|
return -1;
|
|
|
|
use_malloc = true;
|
|
}
|
|
|
|
/* Copy the data into BUFFER. */
|
|
to_copy = bytes;
|
|
bp = buffer;
|
|
for (i = 0; i < count; ++i)
|
|
{
|
|
size_t copy = MIN (vector[i].iov_len, to_copy);
|
|
|
|
bp = __mempcpy ((void *) bp, (void *) vector[i].iov_base, copy);
|
|
|
|
to_copy -= copy;
|
|
if (to_copy == 0)
|
|
break;
|
|
}
|
|
|
|
bytes_written = __write (fd, buffer, bytes);
|
|
|
|
if (use_malloc)
|
|
free (buffer);
|
|
|
|
return bytes_written;
|
|
}
|
|
#ifndef __writev
|
|
weak_alias (__writev, writev)
|
|
#endif
|