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
|
/*
* islocal.c - returns true if user is registered in the local
* /etc/passwd file. Written by Álvaro Martínez Echevarria,
* alvaro@enano.etsit.upm.es, to allow peaceful coexistence with yp. Nov 94.
*
* Hacked a bit by poe@daimi.aau.dk
* See also ftp://ftp.daimi.aau.dk/pub/linux/poe/admutil*
*
* Hacked by Peter Breitenlohner, peb@mppmu.mpg.de,
* to distinguish user names where one is a prefix of the other,
* and to use "pathnames.h". Oct 5, 96.
*
* 1999-02-22 Arkadiusz Miśkiewicz <misiek@pld.ORG.PL>
* - added Native Language Support
*
* 2008-04-06 James Youngman, jay@gnu.org
* - Completely rewritten to remove assumption that /etc/passwd
* lines are < 1024 characters long. Also added unit tests.
*/
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include "closestream.h"
#include "islocal.h"
#include "nls.h"
#include "pathnames.h"
static int is_local_in_file(const char *user, const char *filename)
{
int local = 0;
size_t match;
int chin, skip;
FILE *f;
if (NULL == (f = fopen(filename, "r")))
return -1;
match = 0u;
skip = 0;
while ((chin = getc(f)) != EOF) {
if (skip) {
/* Looking for the start of the next line. */
if ('\n' == chin) {
/* Start matching username at the next char. */
skip = 0;
match = 0u;
}
} else {
if (':' == chin) {
if (0 == user[match]) {
/* Success. */
local = 1;
/* next line has no test coverage,
* but it is just an optimisation
* anyway. */
break;
} else {
/* we read a whole username, but it
* is the wrong user. Skip to the
* next line. */
skip = 1;
}
} else if ('\n' == chin) {
/* This line contains no colon; it's
* malformed. No skip since we are already
* at the start of the next line. */
match = 0u;
} else if (chin != user[match]) {
/* username does not match. */
skip = 1;
} else {
++match;
}
}
}
fclose(f);
return local;
}
int is_local(const char *user)
{
int rv;
if ((rv = is_local_in_file(user, _PATH_PASSWD)) < 0)
err(EXIT_FAILURE, _("cannot open %s"), _PATH_PASSWD);
return rv;
}
#ifdef TEST_PROGRAM
int main(int argc, char *argv[])
{
atexit(close_stdout);
if (argc <= 2) {
fprintf(stderr, _("Usage: %s <passwordfile> <username>...\n"),
argv[0]);
return 1;
} else {
int i;
for (i = 2; i < argc; i++) {
const int rv = is_local_in_file(argv[i], argv[1]);
if (rv < 0) {
perror(argv[1]);
return 2;
}
printf("%d:%s\n", rv, argv[i]);
}
return 0;
}
}
#endif
|
