1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
|
/* Copyright (C) 1991, 1992 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 Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA. */
#include <ansidecl.h>
#include <stddef.h>
#include <errno.h>
#include <unistd.h>
#include <string.h>
#include <stdio.h>
#include <limits.h>
#include <fcntl.h>
#include <utmp.h>
/* Defined in ttyname.c. */
extern char *__ttyname;
/* 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. */
char *
DEFUN_VOID(getlogin)
{
char save_tty_pathname[2 + 2 * NAME_MAX];
char *save_ttyname;
char *real_tty_path;
char *result = NULL;
FILE *f;
static struct utmp ut;
if (__ttyname == NULL)
save_ttyname = NULL;
else
save_ttyname = strcpy (save_tty_pathname, __ttyname);
{
int err;
int d = __open ("/dev/tty", 0);
if (d < 0)
return NULL;
real_tty_path = ttyname (d);
err = errno;
(void) close (d);
if (real_tty_path == NULL)
{
errno = err;
return NULL;
}
}
real_tty_path += 5; /* Remove "/dev/". */
f = fopen ("/etc/utmp", "r");
if (f != NULL)
{
while (fread ((PTR) &ut, sizeof(ut), 1, f) == 1)
if (!strncmp (ut.ut_line, real_tty_path, sizeof (ut.ut_line)))
{
result = ut.ut_name;
/* The name is not null-terminated if
it is as long as sizeof (ut.ut_name). */
result[sizeof (ut.ut_name)] = '\0';
break;
}
(void) fclose (f);
}
if (save_ttyname != NULL)
strcpy (__ttyname, save_ttyname);
if (result == NULL)
errno = ENOENT;
return result;
}
|
