Nick Kralevich | 1d1011a | 2012-09-06 10:14:03 -0700 | [diff] [blame] | 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 | |
| 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 | |
| 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 | |
| 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 | |
| 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 | |