rexec — return stream to a remote command
int
rexec( |
char ** | ahost, |
int | inport, | |
char * | user, | |
char * | passwd, | |
char * | cmd, | |
int * | fd2p) ; |
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Note |
---|---|
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.
Not in POSIX.1-2001. Present on the BSDs, Solaris, and
many other systems. The rexec
()
function appeared in BSD4.2
.
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.
rcmd(3), rexecd(8)
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