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/*
* ZeroTier One - Network Virtualization Everywhere
* Copyright (C) 2011-2015 ZeroTier, Inc.
*
* 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/>.
*
* --
*
* ZeroTier may be used and distributed under the terms of the GPLv3, which
* are available at: http://www.gnu.org/licenses/gpl-3.0.html
*
* If you would like to embed ZeroTier into a commercial application or
* redistribute it in a modified binary form, please contact ZeroTier Networks
* LLC. Start here: http://www.zerotier.com/
*/
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
#include <sys/socket.h>
/* Functions used to pass file descriptors between processes */
ssize_t sock_fd_write(int sock, int fd);
ssize_t sock_fd_read(int sock, void *buf, ssize_t bufsize, int *fd);
ssize_t sock_fd_write(int sock, int fd)
{
ssize_t size;
struct msghdr msg;
struct iovec iov;
char buf = '\0';
int buflen = 1;
union {
struct cmsghdr cmsghdr;
char control[CMSG_SPACE(sizeof (int))];
} cmsgu;
struct cmsghdr *cmsg;
iov.iov_base = &buf;
iov.iov_len = buflen;
msg.msg_name = NULL;
msg.msg_namelen = 0;
msg.msg_iov = &iov;
msg.msg_iovlen = 1;
if (fd != -1) {
msg.msg_control = cmsgu.control;
msg.msg_controllen = sizeof(cmsgu.control);
cmsg = CMSG_FIRSTHDR(&msg);
cmsg->cmsg_len = CMSG_LEN(sizeof (int));
cmsg->cmsg_level = SOL_SOCKET;
cmsg->cmsg_type = SCM_RIGHTS;
*((int *) CMSG_DATA(cmsg)) = fd;
} else {
msg.msg_control = NULL;
msg.msg_controllen = 0;
}
size = sendmsg(sock, &msg, 0);
if (size < 0)
perror ("sendmsg");
return size;
}
ssize_t sock_fd_read(int sock, void *buf, ssize_t bufsize, int *fd)
{
ssize_t size;
if (fd) {
struct msghdr msg;
struct iovec iov;
union {
struct cmsghdr cmsghdr;
char control[CMSG_SPACE(sizeof (int))];
} cmsgu;
struct cmsghdr *cmsg;
iov.iov_base = buf;
iov.iov_len = bufsize;
msg.msg_name = NULL;
msg.msg_namelen = 0;
msg.msg_iov = &iov;
msg.msg_iovlen = 1;
msg.msg_control = cmsgu.control;
msg.msg_controllen = sizeof(cmsgu.control);
size = recvmsg (sock, &msg, 0);
if (size < 0) {
perror ("recvmsg");
exit(1);
}
cmsg = CMSG_FIRSTHDR(&msg);
if (cmsg && cmsg->cmsg_len == CMSG_LEN(sizeof(int))) {
if (cmsg->cmsg_level != SOL_SOCKET) {
fprintf (stderr, "invalid cmsg_level %d\n",
cmsg->cmsg_level);
exit(1);
}
if (cmsg->cmsg_type != SCM_RIGHTS) {
fprintf (stderr, "invalid cmsg_type %d\n",
cmsg->cmsg_type);
exit(1);
}
*fd = *((int *) CMSG_DATA(cmsg));
} else
*fd = -1;
} else {
size = read (sock, buf, bufsize);
if (size < 0) {
perror("read");
exit(1);
}
}
return size;
}
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