1d24ef9d1a
We need to spawn a child to take care of buffered data flushing, if there is any. Expensive, but should be needed rarely.
129 lines
2.8 KiB
C
129 lines
2.8 KiB
C
/*
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* The Qubes OS Project, http://www.qubes-os.org
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*
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* Copyright (C) 2010 Rafal Wojtczuk <rafal@invisiblethingslab.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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*/
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#include <stdio.h>
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#include <unistd.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <ioall.h>
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#include <stdlib.h>
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#include "qrexec.h"
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#include "buffer.h"
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#include "glue.h"
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int flush_client_data(int fd, int clid, struct buffer *buffer)
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{
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int ret;
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int len;
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for (;;) {
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len = buffer_len(buffer);
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if (len > MAX_DATA_CHUNK)
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len = MAX_DATA_CHUNK;
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ret = write(fd, buffer_data(buffer), len);
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if (ret == -1) {
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if (errno != EAGAIN) {
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return WRITE_STDIN_ERROR;
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} else
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return WRITE_STDIN_BUFFERED;
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}
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buffer_remove(buffer, len);
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len = buffer_len(buffer);
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if (!len) {
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struct server_header s_hdr;
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s_hdr.type = MSG_XON;
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s_hdr.clid = clid;
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s_hdr.len = 0;
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write_all_vchan_ext(&s_hdr, sizeof s_hdr);
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return WRITE_STDIN_OK;
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}
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}
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}
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int write_stdin(int fd, int clid, char *data, int len,
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struct buffer *buffer)
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{
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int ret;
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if (buffer_len(buffer)) {
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buffer_append(buffer, data, len);
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return WRITE_STDIN_BUFFERED;
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}
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ret = write(fd, data, len);
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if (ret == len)
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return WRITE_STDIN_OK;
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if (ret == -1) {
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if (errno == EAGAIN) {
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struct server_header s_hdr;
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buffer_append(buffer, data, len);
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s_hdr.type = MSG_XOFF;
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s_hdr.clid = clid;
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s_hdr.len = 0;
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write_all_vchan_ext(&s_hdr, sizeof s_hdr);
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return WRITE_STDIN_BUFFERED;
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} else
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return WRITE_STDIN_ERROR;
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} else {
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fprintf(stderr,
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"writes < PIPE_BUF were supposed to be atomic ?\n");
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return WRITE_STDIN_ERROR;
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}
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}
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void set_nonblock(int fd)
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{
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int fl = fcntl(fd, F_GETFL, 0);
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fcntl(fd, F_SETFL, fl | O_NONBLOCK);
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}
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void set_block(int fd)
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{
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int fl = fcntl(fd, F_GETFL, 0);
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fcntl(fd, F_SETFL, fl & ~O_NONBLOCK);
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}
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int fork_and_flush_stdin(int fd, struct buffer *buffer)
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{
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int i;
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if (!buffer_len(buffer))
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return 0;
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switch (fork()) {
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case -1:
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perror("fork");
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exit(1);
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case 0:
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break;
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default:
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return 1;
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}
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for (i = 0; i < MAX_FDS; i++)
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if (i != fd && i != 2)
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close(i);
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set_block(fd);
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write_all(fd, buffer_data(buffer), buffer_len(buffer));
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exit(0);
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}
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