src/lxc/caps.h

   1 /*
   2  * lxc: linux Container library
   3  *
   4  * (C) Copyright IBM Corp. 2007, 2008
   5  *
   6  * Authors:
   7  * Daniel Lezcano <daniel.lezcano at free.fr>
   8  *
   9  * This library is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public
  11  * License as published by the Free Software Foundation; either
  12  * version 2.1 of the License, or (at your option) any later version.
  13  *
  14  * This library is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with this library; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  22  */
  23
  24 #ifndef __LXC_CAPS_H
  25 #define __LXC_CAPS_H
  26
  27 #include <stdbool.h>
  28
  29 #include "config.h"
  30
  31 #if HAVE_LIBCAP
  32 #include <linux/types.h> /* workaround for libcap < 2.17 bug */
  33 #include <sys/capability.h>
  34
  35 extern int lxc_caps_down(void);
  36 extern int lxc_caps_up(void);
  37 extern int lxc_ambient_caps_up(void);
  38 extern int lxc_ambient_caps_down(void);
  39 extern int lxc_caps_init(void);
  40 extern int lxc_caps_last_cap(void);
  41 extern bool lxc_proc_cap_is_set(cap_value_t cap, cap_flag_t flag);
  42 extern bool lxc_file_cap_is_set(const char *path, cap_value_t cap,
  43                                 cap_flag_t flag);
  44 #else
  45 static inline int lxc_caps_down(void)
  46 {
  47         return 0;
  48 }
  49
  50 static inline int lxc_caps_up(void)
  51 {
  52         return 0;
  53 }
  54
  55 static inline int lxc_ambient_caps_up(void)
  56 {
  57         return 0;
  58 }
  59
  60 static inline int lxc_ambient_caps_down(void)
  61 {
  62         return 0;
  63 }
  64
  65 static inline int lxc_caps_init(void)
  66 {
  67         return 0;
  68 }
  69
  70 static inline int lxc_caps_last_cap(void)
  71 {
  72         return 0;
  73 }
  74
  75 typedef int cap_value_t;
  76 typedef int cap_flag_t;
  77 static inline bool lxc_proc_cap_is_set(cap_value_t cap, cap_flag_t flag)
  78 {
  79         return false;
  80 }
  81
  82 static inline bool lxc_file_cap_is_set(const char *path, cap_value_t cap,
  83                                        cap_flag_t flag)
  84 {
  85         return false;
  86 }
  87 #endif
  88
  89 #define lxc_priv(__lxc_function)                          \
  90         ({                                                \
  91                 __label__ out;                            \
  92                 int __ret, __ret2, ___errno = 0;          \
  93                 __ret = lxc_caps_up();                    \
  94                 if (__ret)                                \
  95                         goto out;                         \
  96                 __ret = __lxc_function;                   \
  97                 if (__ret)                                \
  98                         ___errno = errno;                 \
  99                 __ret2 = lxc_caps_down();                 \
 100         out:                                              \
 101                 __ret ? errno = ___errno, __ret : __ret2; \
 102         })
 103
 104 #define lxc_unpriv(__lxc_function)                        \
 105         ({                                                \
 106                 __label__ out;                            \
 107                 int __ret, __ret2, ___errno = 0;          \
 108                 __ret = lxc_caps_down();                  \
 109                 if (__ret)                                \
 110                         goto out;                         \
 111                 __ret = __lxc_function;                   \
 112                 if (__ret)                                \
 113                         ___errno = errno;                 \
 114                 __ret2 = lxc_caps_up();                   \
 115         out:                                              \
 116                 __ret ? errno = ___errno, __ret : __ret2; \
 117         })
 118 #endif