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
|
/* Initgroups handling in nss_files module.
Copyright (C) 2011-2016 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 <alloca.h>
#include <errno.h>
#include <grp.h>
#include <nss.h>
#include <stdio_ext.h>
#include <string.h>
#include <sys/param.h>
#include <stdbool.h>
#include <stdlib.h>
enum nss_status
_nss_files_initgroups_dyn (const char *user, gid_t group, long int *start,
long int *size, gid_t **groupsp, long int limit,
int *errnop)
{
FILE *stream = fopen ("/etc/group", "rce");
if (stream == NULL)
{
*errnop = errno;
return *errnop == ENOMEM ? NSS_STATUS_TRYAGAIN : NSS_STATUS_UNAVAIL;
}
/* No other thread using this stream. */
__fsetlocking (stream, FSETLOCKING_BYCALLER);
char *line = NULL;
size_t linelen = 0;
enum nss_status status = NSS_STATUS_SUCCESS;
bool any = false;
size_t buflen = 1024;
void *buffer = alloca (buflen);
bool buffer_use_malloc = false;
gid_t *groups = *groupsp;
/* We have to iterate over the entire file. */
while (1)
{
fpos_t pos;
fgetpos (stream, &pos);
ssize_t n = getline (&line, &linelen, stream);
if (n < 0)
{
if (! feof_unlocked (stream))
status = ((*errnop = errno) == ENOMEM
? NSS_STATUS_TRYAGAIN : NSS_STATUS_UNAVAIL);
break;
}
struct group grp;
int res = _nss_files_parse_grent (line, &grp, buffer, buflen, errnop);
if (res == -1)
{
size_t newbuflen = 2 * buflen;
if (buffer_use_malloc || ! __libc_use_alloca (buflen + newbuflen))
{
void *newbuf = realloc (buffer_use_malloc ? buffer : NULL,
newbuflen);
if (newbuf == NULL)
{
*errnop = ENOMEM;
status = NSS_STATUS_TRYAGAIN;
goto out;
}
buffer = newbuf;
buflen = newbuflen;
buffer_use_malloc = true;
}
else
buffer = extend_alloca (buffer, buflen, newbuflen);
/* Reread current line, the parser has clobbered it. */
fsetpos (stream, &pos);
continue;
}
if (res > 0 && grp.gr_gid != group)
for (char **m = grp.gr_mem; *m != NULL; ++m)
if (strcmp (*m, user) == 0)
{
/* Matches user. Insert this group. */
if (*start == *size)
{
/* Need a bigger buffer. */
if (limit > 0 && *size == limit)
/* We reached the maximum. */
goto out;
long int newsize;
if (limit <= 0)
newsize = 2 * *size;
else
newsize = MIN (limit, 2 * *size);
gid_t *newgroups = realloc (groups,
newsize * sizeof (*groups));
if (newgroups == NULL)
{
*errnop = ENOMEM;
status = NSS_STATUS_TRYAGAIN;
goto out;
}
*groupsp = groups = newgroups;
*size = newsize;
}
groups[*start] = grp.gr_gid;
*start += 1;
any = true;
break;
}
}
out:
/* Free memory. */
if (buffer_use_malloc)
free (buffer);
free (line);
fclose (stream);
return status == NSS_STATUS_SUCCESS && !any ? NSS_STATUS_NOTFOUND : status;
}
|
