rexec -- return stream to a remote command
Compatibility Library (libcompat, -lcompat)
rexec(char **ahost, int inport, char *user, char *passwd, char *cmd,
This interface is obsoleted by rcmd(3).
The rexec() function looks up the host *ahost using gethostbyname(3),
returning -1 if the host does not exist. Otherwise *ahost is set to the
standard name of the host. If a username and password are both specified,
then these are used to authenticate to the foreign host; otherwise
the environment and then the user's .netrc file in his home directory are
searched for appropriate information. If all this fails, the user is
prompted for the information.
The port inport specifies which well-known DARPA Internet port to use for
the connection; the call getservbyname("exec", "tcp") (see getservent(3))
will return a pointer to a structure, which contains the necessary port.
The protocol for connection is described in detail in rexecd(8).
If the connection succeeds, a socket in the Internet domain of type
SOCK_STREAM is returned to the caller, and given to the remote command as
stdin and stdout. If fd2p is non-zero, then an auxiliary channel to a
control process will be setup, and a descriptor for it will be placed in
*fd2p. The control process will return diagnostic output from the command
(unit 2) on this channel, and will also accept bytes on this channel
as being UNIX signal numbers, to be forwarded to the process group of the
command. The diagnostic information returned does not include remote
authorization failure, as the secondary connection is set up after authorization
has been verified. If fd2p is 0, then the stderr (unit 2 of the
remote command) will be made the same as the stdout and no provision is
made for sending arbitrary signals to the remote process, although you
may be able to get its attention by using out-of-band data.
The rexec() function appeared in 4.2BSD.
The rexec() function sends the unencrypted password across the network.
The underlying service is considered a big security hole and therefore
not enabled on many sites, see rexecd(8) for explanations.
FreeBSD 5.2.1 June 4, 1993 FreeBSD 5.2.1 [ Back ]