NAME

       rexec, rexec_af - return stream to a remote command

SYNOPSIS

       #define _BSD_SOURCE             /* See feature_test_macros(7) */
       #include <netdb.h>

       int rexec(char **ahost, int inport, char *user,
                 char *passwd, char *cmd, int *fd2p);

       int rexec_af(char **ahost, int inport, char *user,
                    char *passwd, char *cmd, int *fd2p,
                    sa_family_t af);

DESCRIPTION

       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 that  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  nonzero,  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.

   rexec_af()
       The  rexec()  function works over IPv4 (AF_INET).  By contrast, the rexec_af() function provides an extra
       argument, af, that allows the caller to select the protocol.  This argument can be specified as  AF_INET,
       AF_INET6, or AF_UNSPEC (to allow the implementation to select the protocol).

VERSIONS

       The rexec_af() function was added to glibc in version 2.2.

ATTRIBUTES

   Multithreading (see pthreads(7))
       The rexec() and rexec_af() functions are not thread-safe.

CONFORMING TO

       These  functions  are not in POSIX.1-2001.  The rexec() function first appeared in 4.2BSD, and is present
       on the BSDs, Solaris, and many  other  systems.   The  rexec_af()  function  is  more  recent,  and  less
       widespread.

BUGS

       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.

SEE ALSO

       rcmd(3), rexecd(8)

COLOPHON

       This page is part of release 3.54 of the Linux man-pages project.  A  description  of  the  project,  and
       information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.