mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-30 00:31:08 +00:00
9e6863a537
Replace alloca with a scratch_buffer to avoid potential stack overflows. Checked on i686-gnu and x86_64-linux-gnu Message-Id: <20230619144334.2902429-1-josimmon@redhat.com>
89 lines
2.6 KiB
C
89 lines
2.6 KiB
C
/* Copyright (C) 1991-2023 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 <stdlib.h>
|
|
#include <unistd.h>
|
|
#include <string.h>
|
|
#include <limits.h>
|
|
#include <scratch_buffer.h>
|
|
#include <stdbool.h>
|
|
#include <sys/param.h>
|
|
#include <sys/uio.h>
|
|
#include <errno.h>
|
|
|
|
|
|
static void
|
|
ifree (struct scratch_buffer *sbuf)
|
|
{
|
|
scratch_buffer_free (sbuf);
|
|
}
|
|
|
|
/* Read data from file descriptor FD, and put the result in the
|
|
buffers described by VECTOR, which is a vector of COUNT 'struct iovec's.
|
|
The buffers are filled in the order specified.
|
|
Operates just like 'read' (see <unistd.h>) except that data are
|
|
put in VECTOR instead of a contiguous buffer. */
|
|
ssize_t
|
|
__readv (int fd, const struct iovec *vector, int count)
|
|
{
|
|
/* Find the total number of bytes to be read. */
|
|
size_t bytes = 0;
|
|
for (int i = 0; i < count; ++i)
|
|
{
|
|
/* Check for ssize_t overflow. */
|
|
if (SSIZE_MAX - bytes < vector[i].iov_len)
|
|
{
|
|
__set_errno (EINVAL);
|
|
return -1;
|
|
}
|
|
bytes += vector[i].iov_len;
|
|
}
|
|
|
|
/* Allocate a temporary buffer to hold the data. Use a scratch_buffer
|
|
since it's faster for small buffer sizes but can handle larger
|
|
allocations as well. */
|
|
|
|
struct scratch_buffer __attribute__ ((__cleanup__ (ifree))) buf;
|
|
scratch_buffer_init (&buf);
|
|
if (!scratch_buffer_set_array_size (&buf, 1, bytes))
|
|
return -1;
|
|
char *buffer = buf.data;
|
|
|
|
/* Read the data. */
|
|
ssize_t bytes_read = __read (fd, buffer, bytes);
|
|
if (bytes_read < 0)
|
|
return -1;
|
|
|
|
/* Copy the data from BUFFER into the memory specified by VECTOR. */
|
|
bytes = bytes_read;
|
|
for (int i = 0; i < count; ++i)
|
|
{
|
|
size_t copy = MIN (vector[i].iov_len, bytes);
|
|
|
|
(void) memcpy ((void *) vector[i].iov_base, (void *) buffer, copy);
|
|
|
|
buffer += copy;
|
|
bytes -= copy;
|
|
if (bytes == 0)
|
|
break;
|
|
}
|
|
|
|
return bytes_read;
|
|
}
|
|
libc_hidden_def (__readv)
|
|
weak_alias (__readv, readv)
|