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                 const char *disconnected);
  32
  33#define MAX_PATH_BUFFERS 2
  34
  35/* Per cpu buffers used during mediation */
  36/* preallocated buffers to use during path lookups */
  37struct aa_buffers {
  38        char *buf[MAX_PATH_BUFFERS];
  39};
  40
  41#include <linux/percpu.h>
  42#include <linux/preempt.h>
  43
  44DECLARE_PER_CPU(struct aa_buffers, aa_buffers);
  45
  46#define ASSIGN(FN, A, X, N) ((X) = FN(A, N))
  47#define EVAL1(FN, A, X) ASSIGN(FN, A, X, 0) /*X = FN(0)*/
  48#define EVAL2(FN, A, X, Y...)   \
  49        do { ASSIGN(FN, A, X, 1);  EVAL1(FN, A, Y); } while (0)
  50#define EVAL(FN, A, X...) CONCATENATE(EVAL, COUNT_ARGS(X))(FN, A, X)
  51
  52#define for_each_cpu_buffer(I) for ((I) = 0; (I) < MAX_PATH_BUFFERS; (I)++)
  53
  54#ifdef CONFIG_DEBUG_PREEMPT
  55#define AA_BUG_PREEMPT_ENABLED(X) AA_BUG(preempt_count() <= 0, X)
  56#else
  57#define AA_BUG_PREEMPT_ENABLED(X) /* nop */
  58#endif
  59
  60#define __get_buffer(C, N) ({                                           \
  61        AA_BUG_PREEMPT_ENABLED("__get_buffer without preempt disabled");  \
  62        (C)->buf[(N)]; })
  63
  64#define __get_buffers(C, X...)    EVAL(__get_buffer, C, X)
  65
  66#define __put_buffers(X, Y...) ((void)&(X))
  67
  68#define get_buffers(X...)                                               \
  69do {                                                                    \
  70        struct aa_buffers *__cpu_var = get_cpu_ptr(&aa_buffers);        \
  71        __get_buffers(__cpu_var, X);                                    \
  72} while (0)
  73
  74#define put_buffers(X, Y...)            \
  75do {                                    \
  76        __put_buffers(X, Y);            \
  77        put_cpu_ptr(&aa_buffers);       \
  78} while (0)
  79
  80#endif /* __AA_PATH_H */
  81