1 /* Reentrant function to return the current login name. Unix version.
2 Copyright (C) 1991, 1992, 1996, 1997, 1998 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, write to the Free
17 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
29 /* Return at most NAME_LEN characters of the login name of the user in NAME.
30 If it cannot be determined or some other error occurred, return the error
31 code. Otherwise return 0. */
34 getlogin_r (name
, name_len
)
38 char tty_pathname
[2 + 2 * NAME_MAX
];
39 char *real_tty_path
= tty_pathname
;
41 struct utmp
*ut
, line
, buffer
;
43 /* Get name of tty connected to fd 0. Return if not a tty or
44 if fd 0 isn't open. Note that a lot of documentation says that
45 getlogin() is based on the controlling terminal---what they
46 really mean is "the terminal connected to standard input". The
47 getlogin() implementation of DEC Unix, SunOS, Solaris, HP-UX all
48 return NULL if fd 0 has been closed, so this is the compatible
49 thing to do. Note that ttyname(open("/dev/tty")) on those
50 systems returns /dev/tty, so that is not a possible solution for
53 result
= __ttyname_r (0, real_tty_path
, sizeof (tty_pathname
));
58 real_tty_path
+= 5; /* Remove "/dev/". */
61 strncpy (line
.ut_line
, real_tty_path
, sizeof line
.ut_line
);
62 if (__getutline_r (&line
, &buffer
, &ut
) < 0)
65 /* The caller expects ENOENT if nothing is found. */
72 size_t needed
= strlen (ut
->ut_user
) + 1;
74 if (needed
> name_len
)
81 memcpy (name
, ut
->ut_user
, needed
);