1 /* lookup_table.c --
2 * Copyright 2009 Red Hat Inc., Durham, North Carolina.
3 * All Rights Reserved.
4 *
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2.1 of the License, or (at your option) any later version.
9 *
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Lesser General Public License for more details.
14 *
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with this library; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 *
19 * Authors:
20 * Steve Grubb <sgrubb@redhat.com>
21 */
22
23 #include "config.h"
24 #include <stddef.h>
25 #include <linux/capability.h>
26 #include <strings.h>
27
28
29 #ifndef CAP_LAST_CAP
30 #define CAP_LAST_CAP CAP_AUDIT_CONTROL
31 #endif
32 #undef cap_valid
33 #define cap_valid(x) ((x) <= CAP_LAST_CAP)
34
35
36 struct transtab {
37 int value;
38 int offset;
39 };
40
41 #define MSGSTRFIELD(line) MSGSTRFIELD1(line)
42 #define MSGSTRFIELD1(line) str##line
43
44
45 /* To create the following tables in a DSO-friendly way we split them in
46 two separate variables: a long string which is created by concatenating
47 all strings referenced in the table and the table itself, which uses
48 offsets instead of string pointers. To do this without increasing
49 the maintenance burden we use a lot of preprocessor magic. All the
50 maintainer has to do is to add a new entry to the included file and
51 recompile. */
52
53 static const union captab_msgstr_t {
54 struct {
55 #define _S(n, s) char MSGSTRFIELD(__LINE__)[sizeof (s)];
56 #include "captab.h"
57 #undef _S
58 };
59 char str[0];
60 } captab_msgstr = { {
61 #define _S(n, s) s,
62 #include "captab.h"
63 #undef _S
64 } };
65 static const struct transtab captab[] = {
66 #define _S(n, s) { n, offsetof(union captab_msgstr_t, \
67 MSGSTRFIELD(__LINE__)) },
68 #include "captab.h"
69 #undef _S
70 };
71 #define CAP_NG_CAPABILITY_NAMES (sizeof(captab)/sizeof(captab[0]))
72
73
74
75
capng_lookup_name(const struct transtab * table,const char * tabstr,size_t length,const char * name)76 static int capng_lookup_name(const struct transtab *table,
77 const char *tabstr, size_t length, const char *name)
78 {
79 size_t i;
80
81 for (i = 0; i < length; i++) {
82 if (!strcasecmp(tabstr + table[i].offset, name))
83 return table[i].value;
84 }
85 return -1;
86 }
87
capng_lookup_number(const struct transtab * table,const char * tabstr,size_t length,int number)88 static const char *capng_lookup_number(const struct transtab *table,
89 const char *tabstr, size_t length,
90 int number)
91 {
92 size_t i;
93
94 for (i = 0; i < length; i++) {
95 if (table[i].value == number)
96 return tabstr + table[i].offset;
97 }
98 return NULL;
99 }
100
capng_name_to_capability(const char * name)101 int capng_name_to_capability(const char *name)
102 {
103 return capng_lookup_name(captab, captab_msgstr.str,
104 CAP_NG_CAPABILITY_NAMES, name);
105 }
106
capng_capability_to_name(unsigned int capability)107 const char *capng_capability_to_name(unsigned int capability)
108 {
109 if (!cap_valid(capability))
110 return NULL;
111
112 return capng_lookup_number(captab, captab_msgstr.str,
113 CAP_NG_CAPABILITY_NAMES, capability);
114 }
115
116