man2/getdomainname.2

   1 .\" Copyright 1993 Rickard E. Faith (faith@cs.unc.edu)
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  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 2012-10-25 "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 .sp
  35 .BI "int getdomainname(char *" name ", size_t " len );
  36 .br
  37 .BI "int setdomainname(const char *" name ", size_t " len );
  38 .sp
  39 .in -4n
  40 Feature Test Macro Requirements for glibc (see
  41 .BR feature_test_macros (7)):
  42 .in
  43 .sp
  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 is unprivileged (Linux: does not have the
 100 .B CAP_SYS_ADMIN
 101 capability).
 102 .PP
 103 .BR getdomainname ()
 104 can fail with the following errors:
 105 .TP
 106 .B EINVAL
 107 For
 108 .BR getdomainname ()
 109 under libc:
 110 .I name
 111 is NULL or
 112 .I name
 113 is longer than
 114 .I len
 115 bytes.
 116 .SH CONFORMING TO
 117 POSIX does not specify these calls.
 118 .\" But they appear on most systems...
 119 .SH NOTES
 120 Since Linux 1.0, the limit on the length of a domain name,
 121 including the terminating null byte, is 64 bytes.
 122 In older kernels, it was 8 bytes.
 123
 124 On most Linux architectures (including x86),
 125 there is no
 126 .BR getdomainname ()
 127 system call; instead, glibc implements
 128 .BR getdomainname ()
 129 as a library function that returns a copy of the
 130 .I domainname
 131 field returned from a call to
 132 .BR uname (2).
 133 .SH SEE ALSO
 134 .BR gethostname (2),
 135 .BR sethostname (2),
 136 .BR uname (2)