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 19 enum 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 29 int 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 */ 36 struct aa_buffers { 37 char *buf[MAX_PATH_BUFFERS]; 38 }; 39 40 #include <linux/percpu.h> 41 #include <linux/preempt.h> 42 43 DECLARE_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...) \ 74 do { \ 75 preempt_disable(); \ 76 __get_buffers(X); \ 77 } while (0) 78 79 #define put_buffers(X, Y...) \ 80 do { \ 81 __put_buffers(X, Y); \ 82 preempt_enable(); \ 83 } while (0) 84 85 #endif /* __AA_PATH_H */ 86