| /* Copyright (C) 1991-2018 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 of the License, or (at your option) any later version. |
| |
| The GNU C Library is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library; if not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include <errno.h> |
| #include <unistd.h> |
| #include <string.h> |
| #include <stdio.h> |
| #include <limits.h> |
| #include <fcntl.h> |
| |
| #include <utmp.h> |
| |
| static char name[UT_NAMESIZE + 1]; |
| |
| /* Return the login name of the user, or NULL if it can't be determined. |
| The returned pointer, if not NULL, is good only until the next call. */ |
| |
| #ifdef STATIC |
| STATIC |
| #endif |
| char * |
| getlogin (void) |
| { |
| char tty_pathname[2 + 2 * NAME_MAX]; |
| char *real_tty_path = tty_pathname; |
| int err; |
| char *result = NULL; |
| struct utmp *ut, line, buffer; |
| |
| /* Get name of tty connected to fd 0. Return NULL if not a tty or |
| if fd 0 isn't open. Note that a lot of documentation says that |
| getlogin() is based on the controlling terminal---what they |
| really mean is "the terminal connected to standard input". The |
| getlogin() implementation of DEC Unix, SunOS, Solaris, HP-UX all |
| return NULL if fd 0 has been closed, so this is the compatible |
| thing to do. Note that ttyname(open("/dev/tty")) on those |
| systems returns /dev/tty, so that is not a possible solution for |
| getlogin(). */ |
| err = __ttyname_r (0, real_tty_path, sizeof (tty_pathname)); |
| if (err != 0) |
| { |
| __set_errno (err); |
| return NULL; |
| } |
| |
| real_tty_path += 5; /* Remove "/dev/". */ |
| |
| __setutent (); |
| strncpy (line.ut_line, real_tty_path, sizeof line.ut_line); |
| if (__getutline_r (&line, &buffer, &ut) < 0) |
| { |
| if (errno == ESRCH) |
| /* The caller expects ENOENT if nothing is found. */ |
| __set_errno (ENOENT); |
| result = NULL; |
| } |
| else |
| { |
| strncpy (name, ut->ut_user, UT_NAMESIZE); |
| name[UT_NAMESIZE] = '\0'; |
| result = name; |
| } |
| |
| __endutent (); |
| |
| return result; |
| } |