man2/getdomainname.2

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   3 .\" 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 2009-09-27 "Linux" "Linux Programmer's Manual"
  30 .SH NAME
  31 getdomainname, setdomainname \- get/set 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 _BSD_SOURCE || (_XOPEN_SOURCE && _XOPEN_SOURCE\ <\ 500)
  48 .ad b
  49 .SH DESCRIPTION
  50 These functions are used to access or to change the domain name of the
  51 host system.
  52
  53 .BR setdomainname ()
  54 sets the domain name to the value given in the character array
  55 .IR name .
  56 The
  57 .I len
  58 argument specifies the number of bytes in
  59 .IR name .
  60 (Thus,
  61 .I name
  62 does not require a terminating null byte.)
  63
  64 .BR getdomainname ()
  65 returns the null-terminated domain name in the character array
  66 .IR name ,
  67 which has a length of
  68 .I len
  69 bytes.
  70 If the null-terminated domain name requires more than \fIlen\fP bytes,
  71 .BR getdomainname ()
  72 returns the first \fIlen\fP bytes (glibc) or gives an error (libc).
  73 .SH "RETURN VALUE"
  74 On success, zero is returned.
  75 On error, \-1 is returned, and
  76 .I errno
  77 is set appropriately.
  78 .SH ERRORS
  79 .BR setdomainname ()
  80 can fail with the following errors:
  81 .TP
  82 .B EFAULT
  83 .I name
  84 pointed outside of user address space.
  85 .TP
  86 .B EINVAL
  87 .I len
  88 was negative or too large.
  89 .TP
  90 .B EPERM
  91 the caller is unprivileged (Linux: does not have the
  92 .B CAP_SYS_ADMIN
  93 capability).
  94 .PP
  95 .BR getdomainname ()
  96 can fail with the following errors:
  97 .TP
  98 .B EINVAL
  99 For
 100 .BR getdomainname ()
 101 under libc:
 102 .I name
 103 is NULL or
 104 .I name
 105 is longer than
 106 .I len
 107 bytes.
 108 .SH "CONFORMING TO"
 109 POSIX does not specify these calls.
 110 .\" But they appear on most systems...
 111 .SH NOTES
 112 Since Linux 1.0, the limit on the length of a domain name,
 113 including the terminating null byte, is 64 bytes.
 114 In older kernels, it was 8 bytes.
 115
 116 On most Linux architectures (including x86),
 117 there is no
 118 .BR getdomainname ()
 119 system call; instead, glibc implements
 120 .BR getdomainname ()
 121 as a library function that returns a copy of the
 122 .I domainname
 123 field returned from a call to
 124 .BR uname (2).
 125 .SH "SEE ALSO"
 126 .BR gethostname (2),
 127 .BR sethostname (2),
 128 .BR uname (2)