2004-11-03 13:51:07 +00:00
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.\" $NetBSD: rcmd.3,v 1.9 1996/05/28 02:07:39 mrg Exp $
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.\"
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.\" Copyright (c) 1983, 1991, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the University of
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.\" California, Berkeley and its contributors.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)rcmd.3 8.1 (Berkeley) 6/4/93
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.\"
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.\" Contributed as Linux man page by David A. Holland, 970908
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.\" I have not checked whether the Linux situation is exactly the same.
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2007-12-03 19:53:53 +00:00
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.\"
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2007-12-03 19:59:38 +00:00
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.\" 2007-12-08, mtk, Converted from mdoc to man macros
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2007-12-03 19:53:53 +00:00
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.\"
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2012-04-22 23:15:45 +00:00
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.TH RCMD 3 2012-04-23 "Linux" "Linux Programmer's Manual"
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2007-12-03 19:53:53 +00:00
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.SH NAME
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rcmd, rresvport, iruserok, ruserok \- routines for returning a
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stream to a remote command
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.SH SYNOPSIS
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.nf
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.B #include <netdb.h> \ \ \fP/* Or <unistd.h> on some systems */
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.sp
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.BI "int rcmd(char **" ahost ", int " inport ", const char *" locuser ", "
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2007-12-28 04:49:49 +00:00
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.BI " const char *" remuser ", const char *" cmd ", int *" fd2p );
|
2007-12-03 19:53:53 +00:00
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.sp
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.BI "int rresvport(int *" port );
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.sp
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2007-12-23 17:26:26 +00:00
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.BI "int iruserok(uint32_t " raddr ", int " superuser ", "
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2007-12-03 19:53:53 +00:00
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.BI " const char *" ruser ", const char *" luser );
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.sp
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.BI "int ruserok(const char *" rhost ", int " superuser ", "
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.BI " const char *" ruser ", const char *" luser );
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.fi
|
2007-12-14 07:21:33 +00:00
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.sp
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.in -4n
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Feature Test Macro Requirements for glibc (see
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.BR feature_test_macros (7)):
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.in
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.sp
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.BR rcmd (),
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.BR rresvport (),
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.BR ruserok ():
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_BSD_SOURCE
|
2007-12-03 19:53:53 +00:00
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.SH DESCRIPTION
|
2004-11-03 13:51:07 +00:00
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The
|
2007-12-03 19:53:53 +00:00
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.BR rcmd ()
|
2008-12-04 11:37:25 +00:00
|
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|
function is used by the superuser to execute a command on
|
2004-11-03 13:51:07 +00:00
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a remote machine using an authentication scheme based
|
2008-12-04 11:37:25 +00:00
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on privileged port numbers.
|
2004-11-03 13:51:07 +00:00
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The
|
2007-12-03 19:53:53 +00:00
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|
.BR rresvport ()
|
2004-11-03 13:51:07 +00:00
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function
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returns a descriptor to a socket
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with an address in the privileged port space.
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The
|
2007-12-03 19:53:53 +00:00
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|
.BR iruserok ()
|
2004-11-03 13:51:07 +00:00
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and
|
2007-12-03 19:53:53 +00:00
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.BR ruserok ()
|
2004-11-03 13:51:07 +00:00
|
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|
functions are used by servers
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|
to authenticate clients requesting service with
|
2007-12-03 19:53:53 +00:00
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.BR rcmd ().
|
2004-11-03 13:51:07 +00:00
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|
|
All four functions are present in the same file and are used
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by the
|
2007-12-03 19:53:53 +00:00
|
|
|
.BR rshd (8)
|
2004-11-03 13:51:07 +00:00
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server (among others).
|
2007-12-28 05:38:10 +00:00
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.PP
|
2004-11-03 13:51:07 +00:00
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The
|
2007-12-03 19:53:53 +00:00
|
|
|
.BR rcmd ()
|
2004-11-03 13:51:07 +00:00
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|
function
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|
looks up the host
|
2007-12-03 19:53:53 +00:00
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|
|
.I *ahost
|
2004-11-03 13:51:07 +00:00
|
|
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using
|
2007-12-03 19:53:53 +00:00
|
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|
.BR gethostbyname (3),
|
2004-11-03 13:51:07 +00:00
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returning \-1 if the host does not exist.
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Otherwise
|
2007-12-03 19:53:53 +00:00
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.I *ahost
|
2004-11-03 13:51:07 +00:00
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|
is set to the standard name of the host
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|
|
and a connection is established to a server
|
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|
|
residing at the well-known Internet port
|
2007-12-03 19:53:53 +00:00
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|
.IR inport .
|
2007-12-28 05:38:10 +00:00
|
|
|
.PP
|
2004-11-03 13:51:07 +00:00
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|
|
If the connection succeeds,
|
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|
a socket in the Internet domain of type
|
2007-12-03 19:53:53 +00:00
|
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|
.BR SOCK_STREAM
|
2004-11-03 13:51:07 +00:00
|
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|
is returned to the caller, and given to the remote
|
2007-04-12 22:42:49 +00:00
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|
command as
|
2007-12-03 19:53:53 +00:00
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.IR stdin
|
2004-11-03 13:51:07 +00:00
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|
and
|
2007-12-03 19:53:53 +00:00
|
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|
.IR stdout .
|
2004-11-03 13:51:07 +00:00
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If
|
2007-12-03 19:53:53 +00:00
|
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|
.I fd2p
|
intro.1, time.1, adjtimex.2, capget.2, eventfd.2, fcntl.2, getrlimit.2, getsockopt.2, gettimeofday.2, intro.2, ioctl_list.2, ioperm.2, mlock.2, pivot_root.2, poll.2, prctl.2, ptrace.2, sched_setscheduler.2, select_tut.2, semget.2, sigaltstack.2, signalfd.2, sysctl.2, timer_settime.2, timerfd_create.2, wait.2, CPU_SET.3, argz_add.3, assert_perror.3, atexit.3, backtrace.3, bcmp.3, clearenv.3, ctime.3, dl_iterate_phdr.3, dlopen.3, ecvt.3, errno.3, error.3, ether_aton.3, exit.3, fenv.3, ferror.3, finite.3, flockfile.3, fnmatch.3, fpathconf.3, fpclassify.3, ftime.3, ftok.3, ftw.3, fwide.3, getaddrinfo.3, gethostbyname.3, getlogin.3, getnameinfo.3, getnetent.3, getopt.3, getprotoent.3, getrpcent.3, getservent.3, glob.3, hsearch.3, inet.3, isalpha.3, iswalnum.3, iswalpha.3, iswblank.3, iswcntrl.3, iswctype.3, iswdigit.3, iswgraph.3, iswlower.3, iswprint.3, iswpunct.3, iswspace.3, iswupper.3, iswxdigit.3, longjmp.3, lsearch.3, malloc.3, matherr.3, mblen.3, mbsinit.3, mbtowc.3, on_exit.3, printf.3, pthread_attr_init.3, pthread_attr_setaffinity_np.3, pthread_attr_setdetachstate.3, pthread_attr_setguardsize.3, pthread_attr_setinheritsched.3, pthread_attr_setschedparam.3, pthread_attr_setschedpolicy.3, pthread_attr_setscope.3, pthread_attr_setstack.3, pthread_attr_setstackaddr.3, pthread_attr_setstacksize.3, pthread_cancel.3, pthread_cleanup_push.3, pthread_equal.3, pthread_getattr_np.3, pthread_getcpuclockid.3, pthread_setaffinity_np.3, pthread_setcancelstate.3, pthread_setconcurrency.3, pthread_setschedparam.3, pthread_setschedprio.3, ptsname.3, putenv.3, putgrent.3, raise.3, rcmd.3, regex.3, rexec.3, rpc.3, rpmatch.3, rtnetlink.3, scandir.3, sem_init.3, setaliasent.3, setbuf.3, setenv.3, setjmp.3, signbit.3, stdio_ext.3, strtod.3, strtol.3, strtoul.3, system.3, termios.3, timeradd.3, tzset.3, ualarm.3, wctomb.3, xdr.3, st.4, tty_ioctl.4, core.5, elf.5, proc.5, bootparam.7, capabilities.7, icmp.7, ip.7, ipv6.7, math_error.7, mdoc.samples.7, mq_overview.7, pthreads.7, raw.7, regex.7, socket.7, tcp.7, tzselect.8: Global fix: s/non-zero/nonzero/
The tendency in English, as prescribed in style guides like
Chicago MoS, is towards removing hyphens after prefixes
like "non-" etc.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-01-16 16:40:55 +00:00
|
|
|
is nonzero, then an auxiliary channel to a control
|
2004-11-03 13:51:07 +00:00
|
|
|
process will be set up, and a descriptor for it will be placed
|
|
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|
|
in
|
2007-12-03 19:53:53 +00:00
|
|
|
.IR *fd2p .
|
2004-11-03 13:51:07 +00:00
|
|
|
The control process will return diagnostic
|
|
|
|
|
output from the command (unit 2) on this channel, and will also
|
intro.1, time.1, accept.2, bind.2, connect.2, execve.2, flock.2, getdents.2, getpriority.2, getuid.2, intro.2, ioctl.2, mincore.2, mknod.2, personality.2, ptrace.2, read.2, recv.2, select_tut.2, send.2, sendfile.2, shmctl.2, sigaction.2, signal.2, stat.2, times.2, truncate.2, umask.2, wait.2, MB_CUR_MAX.3, MB_LEN_MAX.3, argz_add.3, btowc.3, clearenv.3, clock.3, cmsg.3, end.3, endian.3, errno.3, exit.3, fgetwc.3, fgetws.3, fopen.3, fputwc.3, fputws.3, fseek.3, fwide.3, getfsent.3, getgrnam.3, gethostid.3, getipnodebyname.3, getmntent.3, getpwnam.3, getwchar.3, grantpt.3, iconv.3, iconv_close.3, iconv_open.3, insque.3, intro.3, iswalnum.3, iswalpha.3, iswblank.3, iswcntrl.3, iswctype.3, iswdigit.3, iswgraph.3, iswlower.3, iswprint.3, iswpunct.3, iswspace.3, iswupper.3, iswxdigit.3, malloc.3, mblen.3, mbrlen.3, mbrtowc.3, mbsinit.3, mbsnrtowcs.3, mbsrtowcs.3, mbstowcs.3, mbtowc.3, mkstemp.3, mktemp.3, nl_langinfo.3, openpty.3, posix_openpt.3, printf.3, ptsname.3, putwchar.3, qecvt.3, rcmd.3, readdir.3, rexec.3, rpc.3, setnetgrent.3, shm_open.3, sigpause.3, stdin.3, stpcpy.3, strftime.3, strptime.3, syslog.3, towctrans.3, towlower.3, towupper.3, ttyslot.3, ungetwc.3, unlocked_stdio.3, wcpcpy.3, wcpncpy.3, wcrtomb.3, wcscasecmp.3, wcscat.3, wcschr.3, wcscmp.3, wcscpy.3, wcscspn.3, wcsdup.3, wcslen.3, wcsncasecmp.3, wcsncat.3, wcsncmp.3, wcsncpy.3, wcsnlen.3, wcsnrtombs.3, wcspbrk.3, wcsrchr.3, wcsrtombs.3, wcsspn.3, wcsstr.3, wcstok.3, wcstombs.3, wcswidth.3, wctob.3, wctomb.3, wctrans.3, wctype.3, wcwidth.3, wmemchr.3, wmemcmp.3, wmemcpy.3, wmemmove.3, wmemset.3, wprintf.3, console_ioctl.4, pts.4, elf.5, filesystems.5, hosts.5, proc.5, ttytype.5, boot.7, capabilities.7, credentials.7, epoll.7, glob.7, koi8-r.7, path_resolution.7, pty.7, signal.7, suffixes.7, time.7, unicode.7, unix.7, uri.7, utf-8.7: global fix: s/Unix/UNIX/
The man pages were rather inconsistent in the use of "Unix"
versus "UNIX". Let's go with the trademark usage.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-10-12 04:45:38 +00:00
|
|
|
accept bytes on this channel as being UNIX signal numbers, to be
|
2004-11-03 13:51:07 +00:00
|
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|
forwarded to the process group of the command.
|
|
|
|
|
If
|
2007-12-03 19:53:53 +00:00
|
|
|
.I fd2p
|
2007-04-12 22:42:49 +00:00
|
|
|
is 0, then the
|
2007-12-03 19:53:53 +00:00
|
|
|
.IR stderr
|
2004-11-03 13:51:07 +00:00
|
|
|
(unit 2 of the remote
|
2007-04-12 22:42:49 +00:00
|
|
|
command) will be made the same as the
|
2007-12-03 19:53:53 +00:00
|
|
|
.IR stdout
|
2004-11-03 13:51:07 +00:00
|
|
|
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.
|
2007-12-28 05:38:10 +00:00
|
|
|
.PP
|
2004-11-03 13:51:07 +00:00
|
|
|
The protocol is described in detail in
|
2007-12-03 19:53:53 +00:00
|
|
|
.BR rshd (8).
|
2007-12-28 05:38:10 +00:00
|
|
|
.PP
|
2004-11-03 13:51:07 +00:00
|
|
|
The
|
2007-12-03 19:53:53 +00:00
|
|
|
.BR rresvport ()
|
2004-11-03 13:51:07 +00:00
|
|
|
function is used to obtain a socket with a privileged
|
2012-04-22 23:15:45 +00:00
|
|
|
port bound to it.
|
2007-04-12 22:42:49 +00:00
|
|
|
This socket is suitable for use by
|
2007-12-03 19:53:53 +00:00
|
|
|
.BR rcmd ()
|
2007-04-12 22:42:49 +00:00
|
|
|
and several other functions.
|
2012-04-22 23:15:45 +00:00
|
|
|
Privileged ports are those in the range 0 to 1023.
|
|
|
|
|
Only a privileged process
|
|
|
|
|
.RB ( CAP_NET_BIND_SERVICE )
|
|
|
|
|
is allowed to bind to a privileged port.
|
|
|
|
|
In the glibc implementation,
|
|
|
|
|
this function restricts its search to the ports from 512 to 1023.
|
|
|
|
|
The
|
|
|
|
|
.I port
|
|
|
|
|
argument is value-result:
|
|
|
|
|
the value it supplies to the call is used as the starting point
|
|
|
|
|
for a circular search of the port range;
|
|
|
|
|
on (successful) return, it contains the port number that was bound to.
|
2007-12-28 05:38:10 +00:00
|
|
|
.PP
|
2004-11-03 13:51:07 +00:00
|
|
|
The
|
2007-12-03 19:53:53 +00:00
|
|
|
.BR iruserok ()
|
2004-11-03 13:51:07 +00:00
|
|
|
and
|
2007-12-03 19:53:53 +00:00
|
|
|
.BR ruserok ()
|
2004-11-03 13:51:07 +00:00
|
|
|
functions take a remote host's IP address or name, respectively,
|
2008-06-30 14:36:59 +00:00
|
|
|
two usernames and a flag indicating whether the local user's
|
2004-11-10 18:17:26 +00:00
|
|
|
name is that of the superuser.
|
2004-11-03 13:51:07 +00:00
|
|
|
Then, if the user is
|
2007-12-03 19:53:53 +00:00
|
|
|
.I not
|
2004-11-10 18:17:26 +00:00
|
|
|
the superuser, it checks the
|
2007-12-03 19:53:53 +00:00
|
|
|
.IR /etc/hosts.equiv
|
2004-11-03 13:51:07 +00:00
|
|
|
file.
|
|
|
|
|
If that lookup is not done, or is unsuccessful, the
|
2007-12-03 19:53:53 +00:00
|
|
|
.IR .rhosts
|
2004-11-03 13:51:07 +00:00
|
|
|
in the local user's home directory is checked to see if the request for
|
|
|
|
|
service is allowed.
|
2007-12-28 05:38:10 +00:00
|
|
|
.PP
|
2004-11-03 13:51:07 +00:00
|
|
|
If this file does not exist, is not a regular file, is owned by anyone
|
2006-05-29 01:20:08 +00:00
|
|
|
other than the user or the superuser, or is writable by anyone other
|
2004-11-03 13:51:07 +00:00
|
|
|
than the owner, the check automatically fails.
|
|
|
|
|
Zero is returned if the machine name is listed in the
|
2007-12-03 19:53:53 +00:00
|
|
|
.IR hosts.equiv
|
2008-06-30 14:36:59 +00:00
|
|
|
file, or the host and remote username are found in the
|
2007-12-03 19:53:53 +00:00
|
|
|
.IR .rhosts
|
2004-11-03 13:51:07 +00:00
|
|
|
file; otherwise
|
2007-12-03 19:53:53 +00:00
|
|
|
.BR iruserok ()
|
2004-11-03 13:51:07 +00:00
|
|
|
and
|
2007-12-03 19:53:53 +00:00
|
|
|
.BR ruserok ()
|
2004-11-03 13:51:07 +00:00
|
|
|
return \-1.
|
|
|
|
|
If the local domain (as obtained from
|
2008-09-18 12:30:39 +00:00
|
|
|
.BR gethostname (2))
|
2004-11-03 13:51:07 +00:00
|
|
|
is the same as the remote domain, only the machine name need be specified.
|
2007-12-28 05:38:10 +00:00
|
|
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.PP
|
2004-11-03 13:51:07 +00:00
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If the IP address of the remote host is known,
|
2007-12-03 19:53:53 +00:00
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.BR iruserok ()
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2004-11-03 13:51:07 +00:00
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should be used in preference to
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2007-12-03 19:53:53 +00:00
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.BR ruserok (),
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2004-11-03 13:51:07 +00:00
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as it does not require trusting the DNS server for the remote host's domain.
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2007-12-03 19:53:53 +00:00
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.SH RETURN VALUE
|
2004-11-03 13:51:07 +00:00
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The
|
2007-12-03 19:53:53 +00:00
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|
.BR rcmd ()
|
2004-11-03 13:51:07 +00:00
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function
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|
returns a valid socket descriptor on success.
|
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It returns \-1 on error and prints a diagnostic message on the standard error.
|
2007-12-28 05:38:10 +00:00
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.PP
|
2004-11-03 13:51:07 +00:00
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|
The
|
2007-12-03 19:53:53 +00:00
|
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|
.BR rresvport ()
|
2004-11-03 13:51:07 +00:00
|
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|
function
|
|
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|
returns a valid, bound socket descriptor on success.
|
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|
It returns \-1 on error with the global value
|
2007-12-03 19:53:53 +00:00
|
|
|
.I errno
|
2004-11-03 13:51:07 +00:00
|
|
|
set according to the reason for failure.
|
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|
The error code
|
2007-12-03 19:53:53 +00:00
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|
.BR EAGAIN
|
|
|
|
|
is overloaded to mean "All network ports in use."
|
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|
.SH "CONFORMING TO"
|
2006-08-04 12:39:17 +00:00
|
|
|
Not in POSIX.1-2001.
|
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|
|
Present on the BSDs, Solaris, and many other systems.
|
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|
|
These
|
2007-04-12 22:42:49 +00:00
|
|
|
functions appeared in
|
2007-12-03 19:53:53 +00:00
|
|
|
4.2BSD.
|
2007-12-14 07:21:33 +00:00
|
|
|
.SH BUGS
|
|
|
|
|
.BR iruserok ()
|
2012-03-28 23:44:52 +00:00
|
|
|
is declared in glibc headers only since version 2.12.
|
2007-12-14 07:21:33 +00:00
|
|
|
.\" Bug filed 25 Nov 2007:
|
|
|
|
|
.\" http://sources.redhat.com/bugzilla/show_bug.cgi?id=5399
|
2007-12-03 19:53:53 +00:00
|
|
|
.SH SEE ALSO
|
|
|
|
|
.BR rlogin (1),
|
|
|
|
|
.BR rsh (1),
|
|
|
|
|
.BR intro (2),
|
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|
|
|
.BR rexec (3),
|
|
|
|
|
.BR rexecd (8),
|
|
|
|
|
.BR rlogind (8),
|
|
|
|
|
.BR rshd (8)
|