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 #include "config.h"
  24
  25 #ifndef __LXC_CAPS_H
  26 #define __LXC_CAPS_H
  27
  28 #if HAVE_SYS_CAPABILITY_H
  29 extern int lxc_caps_down(void);
  30 extern int lxc_caps_up(void);
  31 extern int lxc_caps_init(void);
  32
  33 extern int lxc_caps_last_cap(void);
  34 #else
  35 static inline int lxc_caps_down(void) {
  36         return 0;
  37 }
  38 static inline int lxc_caps_up(void) {
  39         return 0;
  40 }
  41 static inline int lxc_caps_init(void) {
  42         return 0;
  43 }
  44
  45 static inline int lxc_caps_last_cap(void) {
  46         return 0;
  47 }
  48 #endif
  49
  50 #define lxc_priv(__lxc_function)                        \
  51         ({                                              \
  52                 __label__ out;                          \
  53                 int __ret, __ret2, ___errno = 0;                \
  54                 __ret = lxc_caps_up();                  \
  55                 if (__ret)                              \
  56                         goto out;                       \
  57                 __ret = __lxc_function;                 \
  58                 if (__ret)                              \
  59                         ___errno = errno;               \
  60                 __ret2 = lxc_caps_down();               \
  61         out:    __ret ? errno = ___errno,__ret : __ret2;        \
  62         })
  63
  64 #define lxc_unpriv(__lxc_function)                      \
  65         ({                                              \
  66                 __label__ out;                          \
  67                 int __ret, __ret2, ___errno = 0;                \
  68                 __ret = lxc_caps_down();                \
  69                 if (__ret)                              \
  70                         goto out;                       \
  71                 __ret = __lxc_function;                 \
  72                 if (__ret)                              \
  73                         ___errno = errno;               \
  74                 __ret2 = lxc_caps_up();                 \
  75         out:    __ret ? errno = ___errno,__ret : __ret2;        \
  76         })
  77 #endif