man3/getusershell.3

   1 .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
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  25 .\" References consulted:
  26 .\"     Linux libc source code
  27 .\"     Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
  28 .\"     386BSD man pages
  29 .\" Modified Sat Jul 24 19:17:53 1993 by Rik Faith (faith@cs.unc.edu)
  30 .TH GETUSERSHELL 3  2016-03-15 "GNU" "Linux Programmer's Manual"
  31 .SH NAME
  32 getusershell, setusershell, endusershell \- get permitted user shells
  33 .SH SYNOPSIS
  34 .nf
  35 .B #include <unistd.h>
  36 .PP
  37 .B char *getusershell(void);
  38 .PP
  39 .B void setusershell(void);
  40 .PP
  41 .B void endusershell(void);
  42 .fi
  43 .PP
  44 .in -4n
  45 Feature Test Macro Requirements for glibc (see
  46 .BR feature_test_macros (7)):
  47 .in
  48 .PP
  49 .ad l
  50 .BR getusershell (),
  51 .BR setusershell (),
  52 .BR endusershell ():
  53 .nf
  54     Since glibc 2.21:
  55 .\"             commit 266865c0e7b79d4196e2cc393693463f03c90bd8
  56         _DEFAULT_SOURCE
  57     In glibc 2.19 and 2.20:
  58         _DEFAULT_SOURCE || (_XOPEN_SOURCE && _XOPEN_SOURCE\ <\ 500)
  59     Up to and including glibc 2.19:
  60         _BSD_SOURCE || (_XOPEN_SOURCE && _XOPEN_SOURCE\ <\ 500)
  61 .fi
  62 .ad b
  63 .SH DESCRIPTION
  64 The
  65 .BR getusershell ()
  66 function returns the next line from the file
  67 .IR /etc/shells ,
  68 opening the file if necessary.
  69 The line should contain
  70 the pathname of a valid user shell.
  71 If
  72 .I /etc/shells
  73 does not exist or
  74 is unreadable,
  75 .BR getusershell ()
  76 behaves as if
  77 .I /bin/sh
  78 and
  79 .I /bin/csh
  80 were listed in the file.
  81 .PP
  82 The
  83 .BR setusershell ()
  84 function rewinds
  85 .IR /etc/shells .
  86 .PP
  87 The
  88 .BR endusershell ()
  89 function closes
  90 .IR /etc/shells .
  91 .SH RETURN VALUE
  92 The
  93 .BR getusershell ()
  94 function returns NULL on end-of-file.
  95 .SH FILES
  96 .nf
  97 /etc/shells
  98 .fi
  99 .SH ATTRIBUTES
 100 For an explanation of the terms used in this section, see
 101 .BR attributes (7).
 102 .TS
 103 allbox;
 104 lbw31 lb lb
 105 l l l.
 106 Interface       Attribute       Value
 107 T{
 108 .BR getusershell (),
 109 .BR setusershell (),
 110 .br
 111 .BR endusershell ()
 112 T}      Thread safety   MT-Unsafe
 113 .TE
 114 .SH CONFORMING TO
 115 4.3BSD.
 116 .SH SEE ALSO
 117 .BR shells (5)