qubes-linux-utils/qrexec-lib/write-stdin.c
Marek Marczykowski-Górecki 774803003e
qrexec-lib: convert tabs to spaces
- Fix compile error on gcc 6 (-Werror=misleading-indentation)
- Follow coding style: https://www.qubes-os.org/doc/coding-style/

(cherry picked from commit 410ad3d25f)
2016-06-21 04:32:49 +02:00

120 lines
3.3 KiB
C

/*
* The Qubes OS Project, http://www.qubes-os.org
*
* Copyright (C) 2010 Rafal Wojtczuk <rafal@invisiblethingslab.com>
*
* 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 2
* 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, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
*/
#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <libvchan.h>
#include "qrexec.h"
#include "libqrexec-utils.h"
/*
There is buffered data in "buffer" for client and select()
reports that "fd" is writable. Write as much as possible to fd.
*/
int flush_client_data(int fd, struct buffer *buffer)
{
int ret;
int len;
for (;;) {
len = buffer_len(buffer);
if (!len) {
return WRITE_STDIN_OK;
}
if (len > MAX_DATA_CHUNK)
len = MAX_DATA_CHUNK;
ret = write(fd, buffer_data(buffer), len);
if (ret == -1) {
if (errno != EAGAIN) {
return WRITE_STDIN_ERROR;
} else
return WRITE_STDIN_BUFFERED;
}
// we previously called buffer_remove(buffer, len)
// it will be wrong if we change MAX_DATA_CHUNK to something large
// as pipes writes are atomic only to PIPE_MAX limit
buffer_remove(buffer, ret);
}
}
/*
* Write "len" bytes from "data" to "fd". If not all written, buffer the rest
* to "buffer".
*/
int write_stdin(int fd, const char *data, int len, struct buffer *buffer)
{
int ret;
int written = 0;
if (buffer_len(buffer)) {
buffer_append(buffer, data, len);
return WRITE_STDIN_BUFFERED;
}
while (written < len) {
ret = write(fd, data + written, len - written);
if (ret == 0) {
perror("write_stdin: write returns 0 ???");
exit(1);
}
if (ret == -1) {
if (errno != EAGAIN)
return WRITE_STDIN_ERROR;
buffer_append(buffer, data + written,
len - written);
return WRITE_STDIN_BUFFERED;
}
written += ret;
}
return WRITE_STDIN_OK;
}
/*
* Data feed process has exited, so we need to clear all control structures for
* the client. However, if we have buffered data for the client (which is rare btw),
* fire&forget a separate process to flush them.
*/
int fork_and_flush_stdin(int fd, struct buffer *buffer)
{
int i;
if (!buffer_len(buffer))
return 0;
switch (fork()) {
case -1:
perror("fork");
exit(1);
case 0:
break;
default:
return 1;
}
for (i = 0; i < MAX_FDS; i++)
if (i != fd && i != 2)
close(i);
set_block(fd);
write_all(fd, buffer_data(buffer), buffer_len(buffer));
_exit(0);
}