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privsep_fdpass.c revision 1.1 
      1 /*	$OpenBSD: privsep_fdpass.c,v 1.1 2003/10/22 18:51:55 canacar Exp $	*/
      2 
      3 /*
      4  * Copyright 2001 Niels Provos <provos (at) citi.umich.edu>
      5  * All rights reserved.
      6  *
      7  * Copyright (c) 2002 Matthieu Herrb
      8  * All rights reserved.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  *
     14  *    - Redistributions of source code must retain the above copyright
     15  *      notice, this list of conditions and the following disclaimer.
     16  *    - Redistributions in binary form must reproduce the above
     17  *      copyright notice, this list of conditions and the following
     18  *      disclaimer in the documentation and/or other materials provided
     19  *      with the distribution.
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     22  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
     24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
     25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
     26  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
     27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
     29  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
     31  * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     32  * POSSIBILITY OF SUCH DAMAGE.
     33  */
     34 #include <sys/param.h>
     35 #include <sys/uio.h>
     36 #include <sys/types.h>
     37 #include <sys/socket.h>
     38 #include <sys/stat.h>
     39 #include <err.h>
     40 #include <errno.h>
     41 #include <fcntl.h>
     42 #include <signal.h>
     43 #include <stdio.h>
     44 #include <stdlib.h>
     45 #include <string.h>
     46 #include <unistd.h>
     47 #include "pflogd.h"
     48 
     49 void
     50 send_fd(int sock, int fd)
     51 {
     52 	struct msghdr msg;
     53 	char tmp[CMSG_SPACE(sizeof(int))];
     54 	struct cmsghdr *cmsg;
     55 	struct iovec vec;
     56 	int result = 0;
     57 	ssize_t n;
     58 
     59 	memset(&msg, 0, sizeof(msg));
     60 
     61 	if (fd >= 0) {
     62 		msg.msg_control = (caddr_t)tmp;
     63 		msg.msg_controllen = CMSG_LEN(sizeof(int));
     64 		cmsg = CMSG_FIRSTHDR(&msg);
     65 		cmsg->cmsg_len = CMSG_LEN(sizeof(int));
     66 		cmsg->cmsg_level = SOL_SOCKET;
     67 		cmsg->cmsg_type = SCM_RIGHTS;
     68 		*(int *)CMSG_DATA(cmsg) = fd;
     69 	} else {
     70 		result = errno;
     71 	}
     72 
     73 	vec.iov_base = &result;
     74 	vec.iov_len = sizeof(int);
     75 	msg.msg_iov = &vec;
     76 	msg.msg_iovlen = 1;
     77 
     78 	if ((n = sendmsg(sock, &msg, 0)) == -1)
     79 		warn("%s: sendmsg(%d)", __func__, sock);
     80 	if (n != sizeof(int))
     81 		warnx("%s: sendmsg: expected sent 1 got %ld",
     82 		    __func__, (long)n);
     83 }
     84 
     85 int
     86 receive_fd(int sock)
     87 {
     88 	struct msghdr msg;
     89 	char tmp[CMSG_SPACE(sizeof(int))];
     90 	struct cmsghdr *cmsg;
     91 	struct iovec vec;
     92 	ssize_t n;
     93 	int result;
     94 	int fd;
     95 
     96 	memset(&msg, 0, sizeof(msg));
     97 	vec.iov_base = &result;
     98 	vec.iov_len = sizeof(int);
     99 	msg.msg_iov = &vec;
    100 	msg.msg_iovlen = 1;
    101 	msg.msg_control = tmp;
    102 	msg.msg_controllen = sizeof(tmp);
    103 
    104 	if ((n = recvmsg(sock, &msg, 0)) == -1)
    105 		warn("%s: recvmsg", __func__);
    106 	if (n != sizeof(int))
    107 		warnx("%s: recvmsg: expected received 1 got %ld",
    108 		    __func__, (long)n);
    109 	if (result == 0) {
    110 		cmsg = CMSG_FIRSTHDR(&msg);
    111 		if (cmsg->cmsg_type != SCM_RIGHTS)
    112 			warnx("%s: expected type %d got %d", __func__,
    113 			    SCM_RIGHTS, cmsg->cmsg_type);
    114 		fd = (*(int *)CMSG_DATA(cmsg));
    115 		return fd;
    116 	} else {
    117 		errno = result;
    118 		return -1;
    119 	}
    120 }
    121