getusershell(3)

NAME

   getusershell, setusershell, endusershell - get permitted user shells

SYNOPSIS

   #include <unistd.h>

   char *getusershell(void);

   void setusershell(void);

   void endusershell(void);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

   getusershell(), setusershell(), endusershell():
       Since glibc 2.21:
           _DEFAULT_SOURCE
       In glibc 2.19 and 2.20:
           _DEFAULT_SOURCE || (_XOPEN_SOURCE && _XOPEN_SOURCE < 500)
       Up to and including glibc 2.19:
           _BSD_SOURCE || (_XOPEN_SOURCE && _XOPEN_SOURCE < 500)

DESCRIPTION

   The  getusershell()  function  returns  the  next  line  from  the file
   /etc/shells, opening the file if necessary.  The  line  should  contain
   the  pathname  of a valid user shell.  If /etc/shells does not exist or
   is unreadable, getusershell() behaves as if /bin/sh and  /bin/csh  were
   listed in the file.

   The setusershell() function rewinds /etc/shells.

   The endusershell() function closes /etc/shells.

RETURN VALUE

   The getusershell() function returns NULL on end-of-file.

FILES

   /etc/shells

ATTRIBUTES

   For   an   explanation   of   the  terms  used  in  this  section,  see
   attributes(7).

   ┌────────────────────────────────┬───────────────┬───────────┐
   │Interface                       │ Attribute     │ Value     │
   ├────────────────────────────────┼───────────────┼───────────┤
   │getusershell(), setusershell(), │ Thread safety │ MT-Unsafe │
   │endusershell()                  │               │           │
   └────────────────────────────────┴───────────────┴───────────┘

CONFORMING TO

   4.3BSD.

SEE ALSO

   shells(5)

COLOPHON

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   description  of  the project, information about reporting bugs, and the
   latest    version    of    this    page,    can     be     found     at
   https://www.kernel.org/doc/man-pages/.

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