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 "config.h"
  28 #include <stdbool.h>
  29
  30 #if HAVE_LIBCAP
  31 #include <linux/types.h> /* workaround for libcap < 2.17 bug */
  32 #include <sys/capability.h>
  33
  34 extern int lxc_caps_down(void);
  35 extern int lxc_caps_up(void);
  36 extern int lxc_ambient_caps_up(void);
  37 extern int lxc_ambient_caps_down(void);
  38 extern int lxc_caps_init(void);
  39 extern int lxc_caps_last_cap(void);
  40 extern bool lxc_proc_cap_is_set(cap_value_t cap, cap_flag_t flag);
  41 extern bool lxc_file_cap_is_set(const char *path, cap_value_t cap,
  42                                 cap_flag_t flag);
  43 #else
  44 static inline int lxc_caps_down(void)
  45 {
  46         return 0;
  47 }
  48
  49 static inline int lxc_caps_up(void)
  50 {
  51         return 0;
  52 }
  53
  54 static inline int lxc_ambient_caps_up(void)
  55 {
  56         return 0;
  57 }
  58
  59 static inline int lxc_ambient_caps_down(void)
  60 {
  61         return 0;
  62 }
  63
  64 static inline int lxc_caps_init(void)
  65 {
  66         return 0;
  67 }
  68
  69 static inline int lxc_caps_last_cap(void)
  70 {
  71         return 0;
  72 }
  73
  74 typedef int cap_value_t;
  75 typedef int cap_flag_t;
  76 static inline bool lxc_proc_cap_is_set(cap_value_t cap, cap_flag_t flag)
  77 {
  78         return false;
  79 }
  80
  81 static inline bool lxc_file_cap_is_set(const char *path, cap_value_t cap,
  82                                        cap_flag_t flag)
  83 {
  84         return false;
  85 }
  86 #endif
  87
  88 #define lxc_priv(__lxc_function)                          \
  89         ({                                                \
  90                 __label__ out;                            \
  91                 int __ret, __ret2, ___errno = 0;          \
  92                 __ret = lxc_caps_up();                    \
  93                 if (__ret)                                \
  94                         goto out;                         \
  95                 __ret = __lxc_function;                   \
  96                 if (__ret)                                \
  97                         ___errno = errno;                 \
  98                 __ret2 = lxc_caps_down();                 \
  99         out:                                              \
 100                 __ret ? errno = ___errno, __ret : __ret2; \
 101         })
 102
 103 #define lxc_unpriv(__lxc_function)                        \
 104         ({                                                \
 105                 __label__ out;                            \
 106                 int __ret, __ret2, ___errno = 0;          \
 107                 __ret = lxc_caps_down();                  \
 108                 if (__ret)                                \
 109                         goto out;                         \
 110                 __ret = __lxc_function;                   \
 111                 if (__ret)                                \
 112                         ___errno = errno;                 \
 113                 __ret2 = lxc_caps_up();                   \
 114         out:                                              \
 115                 __ret ? errno = ___errno, __ret : __ret2; \
 116         })
 117 #endif