man2/getdomainname.2

   1 .\" Copyright 1993 Rickard E. Faith (faith@cs.unc.edu)
   2 .\"
   3 .\" %%%LICENSE_START(VERBATIM)
   4 .\" Permission is granted to make and distribute verbatim copies of this
   5 .\" manual provided the copyright notice and this permission notice are
   6 .\" preserved on all copies.
   7 .\"
   8 .\" Permission is granted to copy and distribute modified versions of this
   9 .\" manual under the conditions for verbatim copying, provided that the
  10 .\" entire resulting derived work is distributed under the terms of a
  11 .\" permission notice identical to this one.
  12 .\"
  13 .\" Since the Linux kernel and libraries are constantly changing, this
  14 .\" manual page may be incorrect or out-of-date.  The author(s) assume no
  15 .\" responsibility for errors or omissions, or for damages resulting from
  16 .\" the use of the information contained herein.  The author(s) may not
  17 .\" have taken the same level of care in the production of this manual,
  18 .\" which is licensed free of charge, as they might when working
  19 .\" professionally.
  20 .\"
  21 .\" Formatted or processed versions of this manual, if unaccompanied by
  22 .\" the source, must acknowledge the copyright and authors of this work.
  23 .\" %%%LICENSE_END
  24 .\"
  25 .\" Modified 1997-08-25 by Nicolás Lichtmaier <nick@debian.org>
  26 .\" Modified 2004-06-17 by Michael Kerrisk <mtk.manpages@gmail.com>
  27 .\" Modified 2008-11-27 by mtk
  28 .\"
  29 .TH GETDOMAINNAME 2 2016-10-08 "Linux" "Linux Programmer's Manual"
  30 .SH NAME
  31 getdomainname, setdomainname \- get/set NIS domain name
  32 .SH SYNOPSIS
  33 .B #include <unistd.h>
  34 .PP
  35 .BI "int getdomainname(char *" name ", size_t " len );
  36 .br
  37 .BI "int setdomainname(const char *" name ", size_t " len );
  38 .PP
  39 .in -4n
  40 Feature Test Macro Requirements for glibc (see
  41 .BR feature_test_macros (7)):
  42 .in
  43 .PP
  44 .ad l
  45 .BR getdomainname (),
  46 .BR setdomainname ():
  47 .nf
  48     Since glibc 2.21:
  49 .\"             commit 266865c0e7b79d4196e2cc393693463f03c90bd8
  50         _DEFAULT_SOURCE
  51     In glibc 2.19 and 2.20:
  52         _DEFAULT_SOURCE || (_XOPEN_SOURCE && _XOPEN_SOURCE\ <\ 500)
  53     Up to and including glibc 2.19:
  54         _BSD_SOURCE || (_XOPEN_SOURCE && _XOPEN_SOURCE\ <\ 500)
  55 .fi
  56 .ad
  57 .SH DESCRIPTION
  58 These functions are used to access or to change the NIS domain name of the
  59 host system.
  60
  61 .BR setdomainname ()
  62 sets the domain name to the value given in the character array
  63 .IR name .
  64 The
  65 .I len
  66 argument specifies the number of bytes in
  67 .IR name .
  68 (Thus,
  69 .I name
  70 does not require a terminating null byte.)
  71
  72 .BR getdomainname ()
  73 returns the null-terminated domain name in the character array
  74 .IR name ,
  75 which has a length of
  76 .I len
  77 bytes.
  78 If the null-terminated domain name requires more than \fIlen\fP bytes,
  79 .BR getdomainname ()
  80 returns the first \fIlen\fP bytes (glibc) or gives an error (libc).
  81 .SH RETURN VALUE
  82 On success, zero is returned.
  83 On error, \-1 is returned, and
  84 .I errno
  85 is set appropriately.
  86 .SH ERRORS
  87 .BR setdomainname ()
  88 can fail with the following errors:
  89 .TP
  90 .B EFAULT
  91 .I name
  92 pointed outside of user address space.
  93 .TP
  94 .B EINVAL
  95 .I len
  96 was negative or too large.
  97 .TP
  98 .B EPERM
  99 The caller did not have the
 100 .B CAP_SYS_ADMIN
 101 capability in the user namespace associated with its UTS namespace (see
 102 .BR namespaces (7)).
 103 .PP
 104 .BR getdomainname ()
 105 can fail with the following errors:
 106 .TP
 107 .B EINVAL
 108 For
 109 .BR getdomainname ()
 110 under libc:
 111 .I name
 112 is NULL or
 113 .I name
 114 is longer than
 115 .I len
 116 bytes.
 117 .SH CONFORMING TO
 118 POSIX does not specify these calls.
 119 .\" But they appear on most systems...
 120 .SH NOTES
 121 Since Linux 1.0, the limit on the length of a domain name,
 122 including the terminating null byte, is 64 bytes.
 123 In older kernels, it was 8 bytes.
 124
 125 On most Linux architectures (including x86),
 126 there is no
 127 .BR getdomainname ()
 128 system call; instead, glibc implements
 129 .BR getdomainname ()
 130 as a library function that returns a copy of the
 131 .I domainname
 132 field returned from a call to
 133 .BR uname (2).
 134 .SH SEE ALSO
 135 .BR gethostname (2),
 136 .BR sethostname (2),
 137 .BR uname (2)