xref: /xnu-11417.121.6/osfmk/kern/assert.h (revision a1e26a70f38d1d7daa7b49b258e2f8538ad81650)
1 /*
2  * Copyright (c) 2000-2016 Apple Inc. All rights reserved.
3  *
4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5  *
6  * This file contains Original Code and/or Modifications of Original Code
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8  * Version 2.0 (the 'License'). You may not use this file except in
9  * compliance with the License. The rights granted to you under the License
10  * may not be used to create, or enable the creation or redistribution of,
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20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
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28 /*
29  * @OSF_COPYRIGHT@
30  */
31 /*
32  * Mach Operating System
33  * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
34  * All Rights Reserved.
35  *
36  * Permission to use, copy, modify and distribute this software and its
37  * documentation is hereby granted, provided that both the copyright
38  * notice and this permission notice appear in all copies of the
39  * software, derivative works or modified versions, and any portions
40  * thereof, and that both notices appear in supporting documentation.
41  *
42  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
43  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
44  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
45  *
46  * Carnegie Mellon requests users of this software to return to
47  *
48  *  Software Distribution Coordinator  or  [email protected]
49  *  School of Computer Science
50  *  Carnegie Mellon University
51  *  Pittsburgh PA 15213-3890
52  *
53  * any improvements or extensions that they make and grant Carnegie Mellon
54  * the rights to redistribute these changes.
55  */
56 /*
57  */
58 
59 #ifndef _KERN_ASSERT_H_
60 #define _KERN_ASSERT_H_
61 
62 /*	assert.h	4.2	85/01/21	*/
63 
64 #include <kern/macro_help.h>
65 #include <sys/cdefs.h>
66 #include <machine/trap.h>
67 
68 #ifdef  XNU_KERNEL_PRIVATE
69 #include <machine/static_if.h>
70 #endif
71 #ifdef  MACH_KERNEL_PRIVATE
72 #include <mach_assert.h>
73 #endif
74 
75 __BEGIN_DECLS
76 
77 __abortlike
78 extern void     Assert(
79 	const char      *file,
80 	int             line,
81 	const char      *expression) __attribute__((noinline));
82 
83 extern int kext_assertions_enable;
84 
85 #ifndef __FILE_NAME__
86 #define __FILE_NAME__ __FILE__
87 #endif
88 #define __Panic(fmt, args...) (panic)(fmt, ##args)
89 
90 __END_DECLS
91 
92 #ifndef APPLE_KEXT_ASSERTIONS
93 #define APPLE_KEXT_ASSERTIONS   0
94 #endif
95 
96 __enum_decl(mach_assert_type_t, unsigned char, {
97 	MACH_ASSERT_DEFAULT,
98 	MACH_ASSERT_3P,
99 	MACH_ASSERT_3S,
100 	MACH_ASSERT_3U,
101 });
102 
103 struct mach_assert_hdr {
104 	mach_assert_type_t      type;
105 	unsigned                lineno : 24;
106 	const char             *filename;
107 } __attribute__((packed, aligned(4)));
108 
109 struct mach_assert_default {
110 	struct mach_assert_hdr  hdr;
111 	const char             *expr;
112 } __attribute__((packed, aligned(4)));
113 
114 struct mach_assert_3x {
115 	struct mach_assert_hdr  hdr;
116 	const char             *a;
117 	const char             *op;
118 	const char             *b;
119 } __attribute__((packed, aligned(4)));
120 
121 #if MACH_ASSERT
122 # if XNU_KERNEL_PRIVATE
123 STATIC_IF_KEY_DECLARE_TRUE(mach_assert);
124 #   define mach_assert_enabled()    improbable_static_if(mach_assert)
125 # else
126 #   define mach_assert_enabled()    1
127 # endif /* !XNU_KERNEL_PRIVATE */
128 #elif APPLE_KEXT_ASSERTIONS
129 #  define mach_assert_enabled()     __builtin_expect(kext_assertions_enable, 0L)
130 #else /* !MACH_ASSERT && !APPLE_KEXT_ASSERTIONS */
131 #  define mach_assert_enabled()     0
132 #endif /* !MACH_ASSERT && !APPLE_KEXT_ASSERTIONS */
133 
134 #define MACH_ASSERT_TRAP_CODE       0xbffc /*  XNU_HARD_TRAP_ASSERT_FAILURE  */
135 #define MACH_ASSERT_SEGSECT         "__DATA_CONST,__assert"
136 
137 /*!
138  * @abstract
139  * Wrap any arbitrary expression/code behind a conditional
140  * on whether assertions are enabled.
141  */
142 #define MACH_ASSERT_DO(...)  ({ \
143 	if (mach_assert_enabled()) { \
144 	        __VA_ARGS__; \
145 	} \
146 })
147 
148 #define mach_assert_abort(reason)  ({ \
149 	__attribute__((used, section(MACH_ASSERT_SEGSECT)))                     \
150 	static const struct mach_assert_default __desc = {                      \
151 	        { MACH_ASSERT_DEFAULT, __LINE__, __FILE_NAME__, },              \
152 	        reason,                                                         \
153 	};                                                                      \
154                                                                                 \
155 	ml_fatal_trap_with_value(MACH_ASSERT_TRAP_CODE, &__desc);               \
156 })
157 
158 /*!
159  * @abstract
160  * assert() that is never elided or removed even in release builds.
161  */
162 #define release_assert(ex) ({ \
163 	if (__builtin_expect(!(ex), 0L)) {                                      \
164 	        mach_assert_abort(#ex);                                         \
165 	}                                                                       \
166 })
167 
168 #if MACH_ASSERT || APPLE_KEXT_ASSERTIONS
169 
170 #define __assert_only
171 
172 #define mach_assert_enabled_expr(ex) \
173 	(mach_assert_enabled() || __builtin_constant_p(!(ex)))
174 
175 #define assert(ex) \
176 	(mach_assert_enabled_expr(ex) && !(ex) \
177 	? (void)mach_assert_abort(#ex) : (void)0)
178 
179 #define assertf(ex, fmt, args...)  ({ \
180 	if (mach_assert_enabled_expr(ex) && __builtin_expect(!(ex), 0L)) {      \
181 	        __Panic("%s:%d Assertion failed: %s : " fmt,                    \
182 	            __FILE_NAME__, __LINE__, # ex, ##args);                     \
183 	}                                                                       \
184 })
185 
186 /*
187  * Each of the following three macros takes three arguments instead of one for
188  * the assertion. The suffixes, 's', u' and 'p' indicate the type of arguments
189  * expected: 'signed', 'unsigned' or 'pointer' respectively.
190  *
191  * assert(a > b)     -> file.c:123 Assertion failed: a > b
192  * assert3u(a, >, b) -> file.c:124 Assertion failed: a > b (1 >= 10)
193  *
194  */
195 #define assert3u(a, op, b)  ({                                                  \
196 	if (mach_assert_enabled_expr((unsigned long long)(a) op                 \
197 	    (unsigned long long)(b))) {                                         \
198 	        const unsigned long long a_ = (a);                              \
199 	        const unsigned long long b_ = (b);                              \
200                                                                                 \
201 	        if (__builtin_expect(!(a_ op b_), 0L)) {                        \
202 	                __attribute__((used, section(MACH_ASSERT_SEGSECT)))     \
203 	                static const struct mach_assert_3x __desc3u = {         \
204 	                        { MACH_ASSERT_3U, __LINE__, __FILE_NAME__, },   \
205 	                        #a, #op, #b,                                    \
206 	                };                                                      \
207                                                                                 \
208 	                ml_fatal_trap_with_value3(MACH_ASSERT_TRAP_CODE,        \
209 	                    &__desc3u, a_, b_);                                 \
210 	        }                                                               \
211 	}                                                                       \
212 })
213 
214 #define assert3s(a, op, b)  ({                                                  \
215 	if (mach_assert_enabled_expr((long long)(a) op ((long long)b))) {       \
216 	        const signed long long a_ = (a);                                \
217 	        const signed long long b_ = (b);                                \
218                                                                                 \
219 	        if (__builtin_expect(!(a_ op b_), 0L)) {                        \
220 	                __attribute__((used, section(MACH_ASSERT_SEGSECT)))     \
221 	                static const struct mach_assert_3x __desc3s = {         \
222 	                        { MACH_ASSERT_3S, __LINE__, __FILE_NAME__, },   \
223 	                        #a, #op, #b,                                    \
224 	                };                                                      \
225                                                                                 \
226 	                ml_fatal_trap_with_value3(MACH_ASSERT_TRAP_CODE,        \
227 	                    &__desc3s, a_, b_);                                 \
228 	        }                                                               \
229 	}                                                                       \
230 })
231 
232 #define assert3p(a, op, b)  ({                                                  \
233 	if (mach_assert_enabled_expr((const void *)(a) op (const void *)(b))) { \
234 	        const void *a_ = (a);                                           \
235 	        const void *b_ = (b);                                           \
236                                                                                 \
237 	        if (__builtin_expect(!(a_ op b_), 0L)) {                        \
238 	                __attribute__((used, section(MACH_ASSERT_SEGSECT)))     \
239 	                static const struct mach_assert_3x __desc3p = {         \
240 	                        { MACH_ASSERT_3P, __LINE__, __FILE_NAME__, },   \
241 	                        #a, #op, #b,                                    \
242 	                };                                                      \
243                                                                                 \
244 	                ml_fatal_trap_with_value3(MACH_ASSERT_TRAP_CODE,        \
245 	                    &__desc3p, a_, b_);                                 \
246 	        }                                                               \
247 	}                                                                       \
248 })
249 
250 #else /* !MACH_ASSERT && !XNU_KERNEL_PRIVATE */
251 
252 #define __assert_only                   __unused
253 #define mach_assert_enabled_expr(ex)    0
254 
255 #define assert(ex)                      ((void)0)
256 #define assertf(ex, fmt, args...)       ((void)0)
257 
258 #define assert3s(a, op, b)              ((void)0)
259 #define assert3u(a, op, b)              ((void)0)
260 #define assert3p(a, op, b)              ((void)0)
261 
262 #endif /* !MACH_ASSERT && !XNU_KERNEL_PRIVATE */
263 
264 /*
265  * static_assert is a C11 / C++0x / C++1z feature.
266  *
267  * Beginning with C++0x, it is a keyword and should not be #defined
268  *
269  * static_assert is not disabled by MACH_ASSERT or NDEBUG
270  */
271 
272 #ifndef __cplusplus
273 	#if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L
274 		#define _STATIC_ASSERT_OVERLOADED_MACRO(_1, _2, NAME, ...) NAME
275 		#define static_assert(...) _STATIC_ASSERT_OVERLOADED_MACRO(__VA_ARGS__, _static_assert_2_args, _static_assert_1_arg)(__VA_ARGS__)
276 
277 		#define _static_assert_2_args(ex, str) _Static_assert((ex), str)
278 		#define _static_assert_1_arg(ex) _Static_assert((ex), #ex)
279 	#endif
280 #else
281 	#if !defined(__cpp_static_assert)
282 /* pre C++11 support */
283 		#define _STATIC_ASSERT_OVERLOADED_MACRO(_1, _2, NAME, ...) NAME
284 		#define static_assert(...) _STATIC_ASSERT_OVERLOADED_MACRO(__VA_ARGS__, _static_assert_2_args, _static_assert_1_arg)(__VA_ARGS__)
285 
286 		#define _static_assert_2_args(ex, str) _Static_assert((ex), str)
287 		#define _static_assert_1_arg(ex) _Static_assert((ex), #ex)
288 	#else
289 /*
290  * C++11 only supports the 2 argument version of static_assert.
291  * C++1z has added support for the 1 argument version.
292  */
293 		#define _static_assert_1_arg(ex) static_assert((ex), #ex)
294 	#endif
295 #endif
296 
297 #endif  /* _KERN_ASSERT_H_ */
298