LXR linux/security/apparmor/include/path.h

   1/*
   2 * AppArmor security module
   3 *
   4 * This file contains AppArmor basic path manipulation function definitions.
   5 *
   6 * Copyright (C) 1998-2008 Novell/SUSE
   7 * Copyright 2009-2010 Canonical Ltd.
   8 *
   9 * This program is free software; you can redistribute it and/or
  10 * modify it under the terms of the GNU General Public License as
  11 * published by the Free Software Foundation, version 2 of the
  12 * License.
  13 */
  14
  15#ifndef __AA_PATH_H
  16#define __AA_PATH_H
  17
  18
  19enum path_flags {
  20        PATH_IS_DIR = 0x1,              /* path is a directory */
  21        PATH_CONNECT_PATH = 0x4,        /* connect disconnected paths to / */
  22        PATH_CHROOT_REL = 0x8,          /* do path lookup relative to chroot */
  23        PATH_CHROOT_NSCONNECT = 0x10,   /* connect paths that are at ns root */
  24
  25        PATH_DELEGATE_DELETED = 0x08000, /* delegate deleted files */
  26        PATH_MEDIATE_DELETED = 0x10000, /* mediate deleted paths */
  27};
  28
  29int aa_path_name(const struct path *path, int flags, char **buffer,
  30                 const char **name, const char **info);
  31
  32#define MAX_PATH_BUFFERS 2
  33
  34/* Per cpu buffers used during mediation */
  35/* preallocated buffers to use during path lookups */
  36struct aa_buffers {
  37        char *buf[MAX_PATH_BUFFERS];
  38};
  39
  40#include <linux/percpu.h>
  41#include <linux/preempt.h>
  42
  43DECLARE_PER_CPU(struct aa_buffers, aa_buffers);
  44
  45#define COUNT_ARGS(X...) COUNT_ARGS_HELPER(, ##X, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
  46#define COUNT_ARGS_HELPER(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, n, X...) n
  47#define CONCAT(X, Y) X ## Y
  48#define CONCAT_AFTER(X, Y) CONCAT(X, Y)
  49
  50#define ASSIGN(FN, X, N) ((X) = FN(N))
  51#define EVAL1(FN, X) ASSIGN(FN, X, 0) /*X = FN(0)*/
  52#define EVAL2(FN, X, Y...) do { ASSIGN(FN, X, 1);  EVAL1(FN, Y); } while (0)
  53#define EVAL(FN, X...) CONCAT_AFTER(EVAL, COUNT_ARGS(X))(FN, X)
  54
  55#define for_each_cpu_buffer(I) for ((I) = 0; (I) < MAX_PATH_BUFFERS; (I)++)
  56
  57#ifdef CONFIG_DEBUG_PREEMPT
  58#define AA_BUG_PREEMPT_ENABLED(X) AA_BUG(preempt_count() <= 0, X)
  59#else
  60#define AA_BUG_PREEMPT_ENABLED(X) /* nop */
  61#endif
  62
  63#define __get_buffer(N) ({                                      \
  64        struct aa_buffers *__cpu_var; \
  65        AA_BUG_PREEMPT_ENABLED("__get_buffer without preempt disabled");  \
  66        __cpu_var = this_cpu_ptr(&aa_buffers);                  \
  67        __cpu_var->buf[(N)]; })
  68
  69#define __get_buffers(X...)    EVAL(__get_buffer, X)
  70
  71#define __put_buffers(X, Y...) ((void)&(X))
  72
  73#define get_buffers(X...)       \
  74do {                            \
  75        preempt_disable();      \
  76        __get_buffers(X);       \
  77} while (0)
  78
  79#define put_buffers(X, Y...)    \
  80do {                            \
  81        __put_buffers(X, Y);    \
  82        preempt_enable();       \
  83} while (0)
  84
  85#endif /* __AA_PATH_H */
  86