вернуть поток удаленной команде (return stream to a remote command)
Имя (Name)
rexec, rexec_af - return stream to a remote command
Синопсис (Synopsis)
#include <netdb.h>
int rexec(char **restrict ahost, int inport,
const char *restrict user, const char *restrict passwd,
const char *restrict cmd, int *restrict fd2p);
int rexec_af(char **restrict ahost, int inport,
const char *restrict user, const char *restrict passwd,
const char *restrict cmd, int *restrict fd2p,
sa_family_t af);
rexec(), rexec_af():
Since glibc 2.19:
_DEFAULT_SOURCE
In glibc up to and including 2.19:
_BSD_SOURCE
Описание (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 .netrc file in user's 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 file
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).
Версии (Versions)
The rexec_af() function was added to glibc in version 2.2.
Атрибуты (Attributes)
For an explanation of the terms used in this section, see
attributes(7).
┌────────────────────────────────────┬───────────────┬───────────┐
│Interface │ Attribute │ Value │
├────────────────────────────────────┼───────────────┼───────────┤
│rexec(), rexec_af() │ Thread safety │ MT-Unsafe │
└────────────────────────────────────┴───────────────┴───────────┘
Стандарты (Conforming to)
These functions are not in POSIX.1. 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.
Ошибки (баги) (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.
Смотри также (See also)
rcmd(3), rexecd(8)
