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      1 /*	$NetBSD: privsep_fdpass.c,v 1.2 2005/07/01 12:43:50 peter Exp $	*/
      2 /*	$OpenBSD: privsep_fdpass.c,v 1.2 2004/08/13 02:51:48 djm Exp $	*/
      3 
      4 /*
      5  * Copyright 2001 Niels Provos <provos (at) citi.umich.edu>
      6  * All rights reserved.
      7  *
      8  * Copyright (c) 2002 Matthieu Herrb
      9  * All rights reserved.
     10  *
     11  * Redistribution and use in source and binary forms, with or without
     12  * modification, are permitted provided that the following conditions
     13  * are met:
     14  *
     15  *    - Redistributions of source code must retain the above copyright
     16  *      notice, this list of conditions and the following disclaimer.
     17  *    - Redistributions in binary form must reproduce the above
     18  *      copyright notice, this list of conditions and the following
     19  *      disclaimer in the documentation and/or other materials provided
     20  *      with the distribution.
     21  *
     22  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     23  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     24  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
     25  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
     26  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
     27  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
     28  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     29  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
     30  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
     32  * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     33  * POSSIBILITY OF SUCH DAMAGE.
     34  */
     35 #include <sys/param.h>
     36 #include <sys/uio.h>
     37 #include <sys/types.h>
     38 #include <sys/socket.h>
     39 #include <sys/stat.h>
     40 #include <err.h>
     41 #include <errno.h>
     42 #include <fcntl.h>
     43 #include <signal.h>
     44 #include <stdio.h>
     45 #include <stdlib.h>
     46 #include <string.h>
     47 #include <unistd.h>
     48 #include "pflogd.h"
     49 
     50 void
     51 send_fd(int sock, int fd)
     52 {
     53 	struct msghdr msg;
     54 	char tmp[CMSG_SPACE(sizeof(int))];
     55 	struct cmsghdr *cmsg;
     56 	struct iovec vec;
     57 	int result = 0;
     58 	ssize_t n;
     59 
     60 	memset(&msg, 0, sizeof(msg));
     61 
     62 	if (fd >= 0) {
     63 		msg.msg_control = (caddr_t)tmp;
     64 		msg.msg_controllen = CMSG_LEN(sizeof(int));
     65 		cmsg = CMSG_FIRSTHDR(&msg);
     66 		cmsg->cmsg_len = CMSG_LEN(sizeof(int));
     67 		cmsg->cmsg_level = SOL_SOCKET;
     68 		cmsg->cmsg_type = SCM_RIGHTS;
     69 		*(int *)CMSG_DATA(cmsg) = fd;
     70 	} else {
     71 		result = errno;
     72 	}
     73 
     74 	vec.iov_base = &result;
     75 	vec.iov_len = sizeof(int);
     76 	msg.msg_iov = &vec;
     77 	msg.msg_iovlen = 1;
     78 
     79 	if ((n = sendmsg(sock, &msg, 0)) == -1)
     80 		warn("%s: sendmsg(%d)", __func__, sock);
     81 	if (n != sizeof(int))
     82 		warnx("%s: sendmsg: expected sent 1 got %ld",
     83 		    __func__, (long)n);
     84 }
     85 
     86 int
     87 receive_fd(int sock)
     88 {
     89 	struct msghdr msg;
     90 	char tmp[CMSG_SPACE(sizeof(int))];
     91 	struct cmsghdr *cmsg;
     92 	struct iovec vec;
     93 	ssize_t n;
     94 	int result;
     95 	int fd;
     96 
     97 	memset(&msg, 0, sizeof(msg));
     98 	vec.iov_base = &result;
     99 	vec.iov_len = sizeof(int);
    100 	msg.msg_iov = &vec;
    101 	msg.msg_iovlen = 1;
    102 	msg.msg_control = tmp;
    103 	msg.msg_controllen = sizeof(tmp);
    104 
    105 	if ((n = recvmsg(sock, &msg, 0)) == -1)
    106 		warn("%s: recvmsg", __func__);
    107 	if (n != sizeof(int))
    108 		warnx("%s: recvmsg: expected received 1 got %ld",
    109 		    __func__, (long)n);
    110 	if (result == 0) {
    111 		cmsg = CMSG_FIRSTHDR(&msg);
    112 		if (cmsg == NULL) {
    113 			warnx("%s: no message header", __func__);
    114 			return -1;
    115 		}
    116 		if (cmsg->cmsg_type != SCM_RIGHTS)
    117 			warnx("%s: expected type %d got %d", __func__,
    118 			    SCM_RIGHTS, cmsg->cmsg_type);
    119 		fd = (*(int *)CMSG_DATA(cmsg));
    120 		return fd;
    121 	} else {
    122 		errno = result;
    123 		return -1;
    124 	}
    125 }
    126