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/*
Unix SMB/Netbios implementation.
Version 3.2.x
recvfile implementations.
Copyright (C) Jeremy Allison 2007.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
/*
* This file handles the OS dependent recvfile implementations.
* The API is such that it returns -1 on error, else returns the
* number of bytes written.
*/
#include "includes.h"
/* Do this on our own in TRANSFER_BUF_SIZE chunks.
* It's safe to make direct syscalls to lseek/write here
* as we're below the Samba vfs layer.
*
* If tofd is -1 we just drain the incoming socket of count
* bytes without writing to the outgoing fd.
* If a write fails we do the same (to cope with disk full)
* errors.
*
* Returns -1 on short reads from fromfd (read error)
* and sets errno.
*
* Returns number of bytes written to 'tofd'
* or thrown away if 'tofd == -1'.
* return != count then sets errno.
* Returns count if complete success.
*/
#ifndef TRANSFER_BUF_SIZE
#define TRANSFER_BUF_SIZE (128*1024)
#endif
static ssize_t default_sys_recvfile(int fromfd,
int tofd,
SMB_OFF_T offset,
size_t count)
{
int saved_errno = 0;
size_t total = 0;
size_t bufsize = MIN(TRANSFER_BUF_SIZE,count);
size_t total_written = 0;
char *buffer = NULL;
if (count == 0) {
return 0;
}
if (tofd != -1 && offset != (SMB_OFF_T)-1) {
if (sys_lseek(tofd, offset, SEEK_SET) == -1) {
if (errno != ESPIPE) {
return -1;
}
}
}
buffer = SMB_MALLOC_ARRAY(char, bufsize);
if (buffer == NULL) {
return -1;
}
while (total < count) {
size_t num_written = 0;
ssize_t read_ret;
size_t toread = MIN(bufsize,count - total);
/* Read from socket - ignore EINTR. */
read_ret = sys_read(fromfd, buffer, toread);
if (read_ret <= 0) {
/* EOF or socket error. */
free(buffer);
return -1;
}
num_written = 0;
while (num_written < read_ret) {
ssize_t write_ret;
if (tofd == -1) {
write_ret = read_ret;
} else {
/* Write to file - ignore EINTR. */
write_ret = sys_write(tofd,
buffer + num_written,
read_ret - num_written);
if (write_ret <= 0) {
/* write error - stop writing. */
tofd = -1;
saved_errno = errno;
continue;
}
}
num_written += (size_t)write_ret;
total_written += (size_t)write_ret;
}
total += read_ret;
}
free(buffer);
if (saved_errno) {
/* Return the correct write error. */
errno = saved_errno;
}
return (ssize_t)total_written;
}
#if defined(HAVE_LINUX_SPLICE)
/*
* Try and use the Linux system call to do this.
* Remember we only return -1 if the socket read
* failed. Else we return the number of bytes
* actually written. We always read count bytes
* from the network in the case of return != -1.
*/
ssize_t sys_recvfile(int fromfd,
int tofd,
SMB_OFF_T offset,
size_t count)
{
static bool try_splice_call = true;
size_t total_written = 0;
if (count == 0) {
return 0;
}
/*
* Older Linux kernels have splice for sendfile,
* but it fails for recvfile. Ensure we only try
* this once and always fall back to the userspace
* implementation if recvfile splice fails. JRA.
*/
if (!try_splice_call) {
return default_sys_recvfile(fromfd,
tofd,
offset,
count);
}
while (total_written < count) {
ssize_t ret = splice(fromfd,
NULL,
tofd,
&offset,
count,
0);
if (ret == -1) {
if (errno != EINTR) {
if (total_written == 0 &&
(errno == EBADF || errno == EINVAL)) {
try_splice_call = false;
return default_sys_recvfile(fromfd,
tofd,
offset,
count);
}
break;
}
continue;
}
total_written += ret;
count -= ret;
}
if (total_written < count) {
int saved_errno = errno;
if (drain_socket(fromfd, count-total_written) !=
count-total_written) {
/* socket is dead. */
return -1;
}
errno = saved_errno;
}
return total_written;
}
#else
/*****************************************************************
No recvfile system call - use the default 128 chunk implementation.
*****************************************************************/
ssize_t sys_recvfile(int fromfd,
int tofd,
SMB_OFF_T offset,
size_t count)
{
return default_sys_recvfile(fromfd, tofd, offset, count);
}
#endif
/*****************************************************************
Throw away "count" bytes from the client socket.
*****************************************************************/
ssize_t drain_socket(int sockfd, size_t count)
{
return default_sys_recvfile(sockfd, -1, (SMB_OFF_T)-1, count);
}
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