monitor_fdpass.c

   1 /* $OpenBSD: monitor_fdpass.c,v 1.19 2010/01/12 00:58:25 djm Exp $ */
   2 /*
   3  * Copyright 2001 Niels Provos <provos@citi.umich.edu>
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  */
  26
  27 #include "includes.h"
  28
  29 #include <sys/types.h>
  30 #include <sys/socket.h>
  31 #include <sys/uio.h>
  32 #ifdef HAVE_SYS_UN_H
  33 #include <sys/un.h>
  34 #endif
  35
  36 #include <errno.h>
  37 #include <poll.h>
  38 #include <string.h>
  39 #include <stdarg.h>
  40
  41 #include "log.h"
  42 #include "monitor_fdpass.h"
  43
  44 int
  45 mm_send_fd(int sock, int fd)
  46 {
  47 #if defined(HAVE_SENDMSG) && (defined(HAVE_ACCRIGHTS_IN_MSGHDR) || defined(HAVE_CONTROL_IN_MSGHDR))
  48         struct msghdr msg;
  49 #ifndef HAVE_ACCRIGHTS_IN_MSGHDR
  50         union {
  51                 struct cmsghdr hdr;
  52                 char buf[CMSG_SPACE(sizeof(int))];
  53         } cmsgbuf;
  54         struct cmsghdr *cmsg;
  55 #endif
  56         struct iovec vec;
  57         char ch = '\0';
  58         ssize_t n;
  59         struct pollfd pfd;
  60
  61         memset(&msg, 0, sizeof(msg));
  62 #ifdef HAVE_ACCRIGHTS_IN_MSGHDR
  63         msg.msg_accrights = (caddr_t)&fd;
  64         msg.msg_accrightslen = sizeof(fd);
  65 #else
  66         msg.msg_control = (caddr_t)&cmsgbuf.buf;
  67         msg.msg_controllen = sizeof(cmsgbuf.buf);
  68         cmsg = CMSG_FIRSTHDR(&msg);
  69         cmsg->cmsg_len = CMSG_LEN(sizeof(int));
  70         cmsg->cmsg_level = SOL_SOCKET;
  71         cmsg->cmsg_type = SCM_RIGHTS;
  72         *(int *)CMSG_DATA(cmsg) = fd;
  73 #endif
  74
  75         vec.iov_base = &ch;
  76         vec.iov_len = 1;
  77         msg.msg_iov = &vec;
  78         msg.msg_iovlen = 1;
  79
  80         pfd.fd = sock;
  81         pfd.events = POLLOUT;
  82         while ((n = sendmsg(sock, &msg, 0)) == -1 &&
  83             (errno == EAGAIN || errno == EINTR)) {
  84                 debug3("%s: sendmsg(%d): %s", __func__, fd, strerror(errno));
  85                 (void)poll(&pfd, 1, -1);
  86         }
  87         if (n == -1) {
  88                 error("%s: sendmsg(%d): %s", __func__, fd,
  89                     strerror(errno));
  90                 return -1;
  91         }
  92
  93         if (n != 1) {
  94                 error("%s: sendmsg: expected sent 1 got %ld",
  95                     __func__, (long)n);
  96                 return -1;
  97         }
  98         return 0;
  99 #else
 100         error("%s: file descriptor passing not supported", __func__);
 101         return -1;
 102 #endif
 103 }
 104
 105 int
 106 mm_receive_fd(int sock)
 107 {
 108 #if defined(HAVE_RECVMSG) && (defined(HAVE_ACCRIGHTS_IN_MSGHDR) || defined(HAVE_CONTROL_IN_MSGHDR))
 109         struct msghdr msg;
 110 #ifndef HAVE_ACCRIGHTS_IN_MSGHDR
 111         union {
 112                 struct cmsghdr hdr;
 113                 char buf[CMSG_SPACE(sizeof(int))];
 114         } cmsgbuf;
 115         struct cmsghdr *cmsg;
 116 #endif
 117         struct iovec vec;
 118         ssize_t n;
 119         char ch;
 120         int fd;
 121         struct pollfd pfd;
 122
 123         memset(&msg, 0, sizeof(msg));
 124         vec.iov_base = &ch;
 125         vec.iov_len = 1;
 126         msg.msg_iov = &vec;
 127         msg.msg_iovlen = 1;
 128 #ifdef HAVE_ACCRIGHTS_IN_MSGHDR
 129         msg.msg_accrights = (caddr_t)&fd;
 130         msg.msg_accrightslen = sizeof(fd);
 131 #else
 132         msg.msg_control = &cmsgbuf.buf;
 133         msg.msg_controllen = sizeof(cmsgbuf.buf);
 134 #endif
 135
 136         pfd.fd = sock;
 137         pfd.events = POLLIN;
 138         while ((n = recvmsg(sock, &msg, 0)) == -1 &&
 139             (errno == EAGAIN || errno == EINTR)) {
 140                 debug3("%s: recvmsg: %s", __func__, strerror(errno));
 141                 (void)poll(&pfd, 1, -1);
 142         }
 143         if (n == -1) {
 144                 error("%s: recvmsg: %s", __func__, strerror(errno));
 145                 return -1;
 146         }
 147
 148         if (n != 1) {
 149                 error("%s: recvmsg: expected received 1 got %ld",
 150                     __func__, (long)n);
 151                 return -1;
 152         }
 153
 154 #ifdef HAVE_ACCRIGHTS_IN_MSGHDR
 155         if (msg.msg_accrightslen != sizeof(fd)) {
 156                 error("%s: no fd", __func__);
 157                 return -1;
 158         }
 159 #else
 160         cmsg = CMSG_FIRSTHDR(&msg);
 161         if (cmsg == NULL) {
 162                 error("%s: no message header", __func__);
 163                 return -1;
 164         }
 165
 166 #ifndef BROKEN_CMSG_TYPE
 167         if (cmsg->cmsg_type != SCM_RIGHTS) {
 168                 error("%s: expected type %d got %d", __func__,
 169                     SCM_RIGHTS, cmsg->cmsg_type);
 170                 return -1;
 171         }
 172 #endif
 173         fd = (*(int *)CMSG_DATA(cmsg));
 174 #endif
 175         return fd;
 176 #else
 177         error("%s: file descriptor passing not supported", __func__);
 178         return -1;
 179 #endif
 180 }