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
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
|
/* Provide a working getlogin_r for systems which lack it.
Copyright (C) 2005-2007, 2010-2025 Free Software Foundation, Inc.
This file 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.
This file 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 this program. If not, see <https://www.gnu.org/licenses/>. */
/* Written by Paul Eggert, Derek Price, and Bruno Haible. */
#include <config.h>
/* Specification. */
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include "malloca.h"
#if defined _WIN32 && ! defined __CYGWIN__
# define WIN32_LEAN_AND_MEAN
# include <windows.h>
/* Don't assume that UNICODE is not defined. */
# undef GetUserName
# define GetUserName GetUserNameA
#else
# if !HAVE_DECL_GETLOGIN
extern char *getlogin (void);
# endif
#endif
#if defined __linux__ || defined __ANDROID__
# include <fcntl.h>
# include <pwd.h>
# include <stdlib.h>
# include <string.h>
# include <sys/stat.h>
#endif
/* See unistd.in.h for documentation. */
int
getlogin_r (char *name, size_t size)
{
#undef getlogin_r
#if defined _WIN32 && ! defined __CYGWIN__
/* Native Windows platform. */
DWORD sz;
/* When size > 0x7fff, the doc says that GetUserName will fail.
Actually, on Windows XP SP3, it succeeds. But let's be safe,
for the sake of older Windows versions. */
if (size > 0x7fff)
size = 0x7fff;
sz = size;
if (!GetUserName (name, &sz))
{
if (GetLastError () == ERROR_INSUFFICIENT_BUFFER)
/* In this case, the doc says that sz contains the required size, but
actually, on Windows XP SP3, it contains 2 * the required size. */
return ERANGE;
else
return ENOENT;
}
return 0;
#elif defined __linux__ || defined __ANDROID__
/* Linux. */
{
/* Read the login uid from the /proc file system. */
int fd = open ("/proc/self/loginuid", O_RDONLY);
if (fd >= 0)
{
char buf[20 + 1];
int n = read (fd, buf, sizeof (buf) - 1);
if (n > 0)
{
buf[n] = '\0';
char *endptr;
unsigned long uid = strtoul (buf, &endptr, 10);
if (endptr == buf + n && uid != (uid_t) -1)
{
/* Convert the uid to a user name. */
struct passwd pbuf1;
char pbuf2[1024];
struct passwd *p;
if (getpwuid_r (uid, &pbuf1, pbuf2, sizeof (pbuf2), &p) == 0)
{
if (strlen (p->pw_name) < size)
{
strcpy (name, p->pw_name);
close (fd);
return 0;
}
return ERANGE;
}
}
}
close (fd);
}
}
{
/* Find the tty connected to the current process. */
char tty[1024];
if (ttyname_r (STDIN_FILENO, tty, sizeof (tty)) == 0)
{
/* We cannot use read_utmp here, since it is not multithread-safe. */
/* Fallback for systems which don't maintain an utmp database
or for ttys that are not recorded in that the utmp database:
Look at the owner of that tty. */
struct stat statbuf;
if (stat (tty, &statbuf) >= 0)
{
uid_t uid = statbuf.st_uid;
/* Convert the uid to a user name. */
struct passwd pbuf1;
char pbuf2[1024];
struct passwd *p;
if (getpwuid_r (uid, &pbuf1, pbuf2, sizeof (pbuf2), &p) == 0)
{
if (strlen (p->pw_name) < size)
{
strcpy (name, p->pw_name);
return 0;
}
return ERANGE;
}
}
}
}
/* ENOENT is a reasonable errno value if getlogin returns NULL. */
return ENOENT;
#elif HAVE_GETLOGIN_R
/* Platform with a getlogin_r() function. */
int ret = getlogin_r (name, size);
if (ret == 0)
{
const char *nul = memchr (name, '\0', size);
if (nul == NULL)
/* name contains a truncated result. */
return ERANGE;
if (size > 0 && nul == name + size - 1)
{
/* strlen(name) == size-1. Determine whether the untruncated result
would have had length size-1 or size. */
char *room = (char *) malloca (size + 1);
if (room == NULL)
return ENOMEM;
ret = getlogin_r (room, size + 1);
/* The untruncated result should be the same as in the first call. */
if (ret == 0 && !memeq (name, room, size))
/* The untruncated result would have been different. */
ret = ERANGE;
freea (room);
}
}
return ret;
#else
/* Platform with a getlogin() function. */
char *n;
size_t nlen;
errno = 0;
n = getlogin ();
if (!n)
/* ENOENT is a reasonable errno value if getlogin returns NULL. */
return (errno != 0 ? errno : ENOENT);
nlen = strlen (n);
if (size <= nlen)
return ERANGE;
memcpy (name, n, nlen + 1);
return 0;
#endif
}
|
