rexec(3N) rexec(3N)
NAME
rexec(), rexec_af() - return stream to a remote command
SYNOPSIS
DESCRIPTION
The routine performs the necessary tasks to arrange for the remote execution of cmd on the remote host as user, who is authenticated with
passwd. Upon completion of authentication, a file descriptor is returned for the socket to which standard input and standard output of cmd
are attached. A command-level interface to is provided by the command (see remsh(1)).
When invoked, looks up host using (see gethostent(3N)) and returns -1 if the host does not exist. The host name can be either the official
name or an alias. If the call succeeds, is set to the standard name of the host. Next, passes a user name and password to the remote host
for authentication, as specified in the user and passwd parameters to If either user or passwd are NULL, searches for the appropriate
information in the file (see netrc(4)) in the user's home directory. If no user or passwd are found, prompts the user for the remote user
name and password, defaulting to the local user name and a NULL password.
The inport variable specifies which TCP port to use for the connection; it is normally the value returned by the following call to
(see getservent(3N)). The protocol used by is described in detail in rexecd(1M).
If the call succeeds, a socket of type is returned to the caller, and given to the remote command as and If connection to a socket is
denied after five tries, or for some other reason (other than the port is in use), returns -1. If fd2p is non-zero, an auxiliary connec-
tion to a control process is set up and a file descriptor for it is placed in The control process returns diagnostic output from the com-
mand on this connection and accepts bytes on this connection, interpreting them as UNIX signal numbers to be forwarded to the process group
of the command. If the auxiliary port cannot be set up, returns -1. If fd2p is 0, of the remote command is made the same as and no provi-
sion is made for sending arbitrary signals to the remote process.
The routine is similar to the routine except for the additional parameter af. The af parameter in the routine can be used to specify an
socket or an socket. If the address family specified in the af argument is not supported, fails with the following error code:
DIAGNOTISCS
When invoked, produces the following diagnostic messages:
The remote host name was not found by
Error in executing the system call. The message specifies the cause of the failure.
Error in connecting to the socket obtained for The message specifies the cause of the failure.
Error in creating a secondary socket for error transmission to be used by
Error in reading information transmitted over the socket. The message specifies the cause of the failure.
The remote host did not connect within 30 seconds to the secondary socket set up as an error connection.
The program attempts to read from the socket and fails. This means the socket connection with the remote host was lost.
Error in opening file in the home directory for a reason other than the file not existing.
The file is readable, writable or executable by someone other than the owner.
Check whether has been modified by someone else and change the mode of
An unrecognized keyword has been found in (see netrc(4)).
Correct the keyword in
While waiting for the secondary socket to be set up, had its primary connection shut down. This may have been caused by an security
failure (see inetd(1M)).
While trying to set up the secondary socket, had an error condition on its primary connection.
While trying to set up a secondary socket, ran out of a resource, which caused the accept to time out.
Repeat the command. If a timeout occurs, check whether the Internet Services are installed and is running.
EXAMPLES
To execute the command on remote host using the remote account is invoked as follows:
WARNINGS
There is no way to specify options to the call that makes.
A program using should not be put in the background when is expected to prompt for a password or user name. Putting in the background will
cause it to compete with the current shell process for input.
Since replaces the pointer to the host name with a pointer to the standard name of the host in a static data area, this value must be
copied into the user's data area if it is to be used later.
The password is sent unencrypted through the socket connection.
AUTHOR
was developed by the University of California, Berkeley.
SEE ALSO
remsh(1), inetd(1M), rexecd(1M), gethostent(3N), getservent(3N), rcmd(3N), netrc(4).
rexec(3N)