1.\" Copyright (c) 1983, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)rexec.3 8.1 (Berkeley) 6/4/93 33.\" $FreeBSD: src/lib/libcompat/4.3/rexec.3,v 1.5.2.4 2001/08/17 15:42:56 ru Exp $ 34.\" $DragonFly: src/lib/libcompat/4.3/rexec.3,v 1.3 2007/07/30 22:11:33 swildner Exp $ 35.\" 36.Dd June 4, 1993 37.Dt REXEC 3 38.Os 39.Sh NAME 40.Nm rexec 41.Nd return stream to a remote command 42.Sh LIBRARY 43.Lb libcompat 44.Sh SYNOPSIS 45.Ft int 46.Fn rexec "char **ahost" "int inport" "char *user" "char *passwd" "char *cmd" "int *fd2p" 47.Sh DESCRIPTION 48.Bf -symbolic 49This interface is obsoleted by 50.Xr rcmd 3 . 51.Ef 52.Pp 53The 54.Fn rexec 55function 56looks up the host 57.Fa *ahost 58using 59.Xr gethostbyname 3 , 60returning \-1 if the host does not exist. 61Otherwise 62.Fa *ahost 63is set to the standard name of the host. 64If a username and password are both specified, then these 65are used to authenticate to the foreign host; otherwise 66the environment and then the user's 67.Pa .netrc 68file in his 69home directory are searched for appropriate information. 70If all this fails, the user is prompted for the information. 71.Pp 72The port 73.Fa inport 74specifies which well-known 75.Tn DARPA 76Internet port to use for 77the connection; the call 78.Fn getservbyname \*qexec\*q \*qtcp\*q 79(see 80.Xr getservent 3 ) 81will return a pointer to a structure, which contains the 82necessary port. 83The protocol for connection is described in detail in 84.Xr rexecd 8 . 85.Pp 86If the connection succeeds, 87a socket in the Internet domain of type 88.Dv SOCK_STREAM 89is returned to 90the caller, and given to the remote command as 91.Em stdin 92and 93.Em stdout . 94If 95.Fa fd2p 96is non-zero, then an auxiliary channel to a control 97process will be setup, and a descriptor for it will be placed 98in 99.Fa *fd2p . 100The control process will return diagnostic 101output from the command (unit 2) on this channel, and will also 102accept bytes on this channel as being 103.Ux 104signal numbers, to be 105forwarded to the process group of the command. The diagnostic 106information returned does not include remote authorization failure, 107as the secondary connection is set up after authorization has been 108verified. 109If 110.Fa fd2p 111is 0, then the 112.Em stderr 113(unit 2 of the remote 114command) will be made the same as the 115.Em stdout 116and no 117provision is made for sending arbitrary signals to the remote process, 118although you may be able to get its attention by using out-of-band data. 119.Sh SEE ALSO 120.Xr rcmd 3 , 121.Xr rexecd 8 122.Sh HISTORY 123The 124.Fn rexec 125function appeared in 126.Bx 4.2 . 127.Sh BUGS 128The 129.Fn rexec 130function sends the unencrypted password across the network. 131.Pp 132The underlying service is considered a big security hole and therefore 133not enabled on many sites, see 134.Xr rexecd 8 135for explanations. 136