REXEC(3SOCKET) Sockets Library Functions REXEC(3SOCKET)
NAME
rexec, rexec_af - return stream to a remote command
SYNOPSIS
cc [
flag ... ]
file...
-lsocket -lnsl [
library... ]
#include <netdb.h>
#include <unistd.h>
int rexec(
char **ahost,
unsigned short inport,
const char *user,
const char *passwd,
const char *cmd,
int *fd2p);
int rexec_af(
char **ahost,
unsigned short inport,
const char *user,
const char *passwd,
const char *cmd,
int *fd2p,
int af);
DESCRIPTION
The
rexec() and
rexec_af() functions look up the host
ahost using
getaddrinfo(3SOCKET) and return
-1 if the host does not exist.
Otherwise
ahost is set to the standard name of the host. The username
and password are used in remote host authentication. When a username
and password are not specified, the
.netrc file in the user's home
directory is searched for the appropriate information. If the search
fails, the user is prompted for the information.
The
rexec() function always returns a socket of the
AF_INET address
family. The
rexec_af() function supports
AF_INET,
AF_INET6, or
AF_UNSPEC for the address family. An application can choose which
type of socket is returned by passing
AF_INET or
AF_INET6 as the
address family. The use of
AF_UNSPEC means that the caller will
accept any address family. Choosing
AF_UNSPEC provides a socket that
best suits the connectivity to the remote host.
The port
inport specifies which
DARPA Internet port to use for the
connection. The port number used must be in network byte order, as
supplied by a call to
htons(3C). The protocol for connection is
described in detail in
in.rexecd(8).
If the call succeeds, a socket of type
SOCK_STREAM is returned to the
caller, and given to the remote command as its standard input and
standard output. If
fd2p is non-zero, an auxiliary channel to a
control process is set up and a file descriptor for it is placed in
*
fd2p. The control process returns diagnostic output (file descriptor
2), from the command on the auxiliary channel. The control process
also accepts bytes on this channel as signal numbers to be forwarded
to the process group of the command. If
fd2p is 0, the standard error
(file descriptor 2) of the remote command is made the same as its
standard output. No provision is made for sending arbitrary signals
to the remote process, other than possibly sending out-of-band data.
There is no way to specify options to the
socket() call made by the
rexec() or
rexec_af()functions.
RETURN VALUES
If
rexec() succeeds, a file descriptor number is returned of the
socket type
SOCK_STREAM and the address family
AF_INET. The parameter
*
ahost is set to the standard name of the host. If the value of
fd2p is other than
NULL, a file descriptor number is placed in *
fd2p which
represents the standard error stream of the command.
If
rexec_af() succeeds, the routine returns a file descriptor number
of the socket type
SOCK_STREAM in the address family
AF_INET or
AF_INET6, as determined by the value of the
af parameter.
If either
rexec() or
rexec_af() fails,
-1 is returned.
ATTRIBUTES
See
attributes(7) for descriptions of the following attributes:
+---------------+-----------------+
|ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+---------------+-----------------+
|MT-Level | Unsafe |
+---------------+-----------------+
This interface is Unsafe in multithreaded applications. Unsafe
interfaces should be called only from the main thread.
SEE ALSO
htonl(3C),
gethostbyname(3NSL),
getaddrinfo(3SOCKET),
getservbyname(3SOCKET),
socket(3SOCKET),
attributes(7),
in.rexecd(8) February 10, 2004 REXEC(3SOCKET)
