guacamole-spice-protocol/src/guacd/move-fd.c

113 lines
3.2 KiB
C

/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
#include "config.h"
#include "move-fd.h"
/* Required for CMSG_* macros on BSD */
#define __BSD_VISIBLE 1
#include <errno.h>
#include <fcntl.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <unistd.h>
int guacd_send_fd(int sock, int fd) {
struct msghdr message = {0};
char message_data[] = {'G'};
/* Assign data buffer */
struct iovec io_vector[1];
io_vector[0].iov_base = message_data;
io_vector[0].iov_len = sizeof(message_data);
message.msg_iov = io_vector;
message.msg_iovlen = 1;
/* Assign ancillary data buffer */
char buffer[CMSG_SPACE(sizeof(fd))] = {0};
message.msg_control = buffer;
message.msg_controllen = sizeof(buffer);
/* Set fields of control message header */
struct cmsghdr* control = CMSG_FIRSTHDR(&message);
control->cmsg_level = SOL_SOCKET;
control->cmsg_type = SCM_RIGHTS;
control->cmsg_len = CMSG_LEN(sizeof(fd));
/* Add file descriptor to message data */
memcpy(CMSG_DATA(control), &fd, sizeof(fd));
/* Send file descriptor */
return (sendmsg(sock, &message, 0) == sizeof(message_data));
}
int guacd_recv_fd(int sock) {
int fd;
struct msghdr message = {0};
char message_data[1];
/* Assign data buffer */
struct iovec io_vector[1];
io_vector[0].iov_base = message_data;
io_vector[0].iov_len = sizeof(message_data);
message.msg_iov = io_vector;
message.msg_iovlen = 1;
/* Assign ancillary data buffer */
char buffer[CMSG_SPACE(sizeof(fd))];
message.msg_control = buffer;
message.msg_controllen = sizeof(buffer);
/* Receive file descriptor */
if (recvmsg(sock, &message, 0) == sizeof(message_data)) {
/* Validate payload */
if (message_data[0] != 'G') {
errno = EPROTO;
return -1;
}
/* Iterate control headers, looking for the sent file descriptor */
struct cmsghdr* control;
for (control = CMSG_FIRSTHDR(&message); control != NULL; control = CMSG_NXTHDR(&message, control)) {
/* Pull file descriptor from data */
if (control->cmsg_level == SOL_SOCKET && control->cmsg_type == SCM_RIGHTS) {
memcpy(&fd, CMSG_DATA(control), sizeof(fd));
return fd;
}
}
} /* end if recvmsg() success */
/* Failed to receive file descriptor */
return -1;
}