1 /* $NetBSD: cdefs.h,v 1.58 2004/12/11 05:59:00 christos Exp $ */ 2 3 /* 4 * Copyright (c) 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Berkeley Software Design, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * @(#)cdefs.h 8.8 (Berkeley) 1/9/95 35 */ 36 37 #ifndef _SYS_CDEFS_H_ 38 #define _SYS_CDEFS_H_ 39 40 #include <android/api-level.h> 41 #include <android/versioning.h> 42 43 #define __BIONIC__ 1 44 45 /* 46 * Testing against Clang-specific extensions. 47 */ 48 #ifndef __has_extension 49 #define __has_extension __has_feature 50 #endif 51 #ifndef __has_feature 52 #define __has_feature(x) 0 53 #endif 54 #ifndef __has_include 55 #define __has_include(x) 0 56 #endif 57 #ifndef __has_builtin 58 #define __has_builtin(x) 0 59 #endif 60 #ifndef __has_attribute 61 #define __has_attribute(x) 0 62 #endif 63 64 #define __strong_alias(alias, sym) \ 65 __asm__(".global " #alias "\n" \ 66 #alias " = " #sym); 67 68 #if defined(__cplusplus) 69 #define __BEGIN_DECLS extern "C" { 70 #define __END_DECLS } 71 #else 72 #define __BEGIN_DECLS 73 #define __END_DECLS 74 #endif 75 76 #if defined(__cplusplus) 77 #define __BIONIC_CAST(_k,_t,_v) (_k<_t>(_v)) 78 #else 79 #define __BIONIC_CAST(_k,_t,_v) ((_t) (_v)) 80 #endif 81 82 #define __BIONIC_ALIGN(__value, __alignment) (((__value) + (__alignment)-1) & ~((__alignment)-1)) 83 84 /* 85 * The __CONCAT macro is used to concatenate parts of symbol names, e.g. 86 * with "#define OLD(foo) __CONCAT(old,foo)", OLD(foo) produces oldfoo. 87 * The __CONCAT macro is a bit tricky -- make sure you don't put spaces 88 * in between its arguments. __CONCAT can also concatenate double-quoted 89 * strings produced by the __STRING macro, but this only works with ANSI C. 90 */ 91 92 #define ___STRING(x) __STRING(x) 93 #define ___CONCAT(x,y) __CONCAT(x,y) 94 95 #if defined(__STDC__) || defined(__cplusplus) 96 #define __P(protos) protos /* full-blown ANSI C */ 97 #define __CONCAT(x,y) x ## y 98 #define __STRING(x) #x 99 100 #if defined(__cplusplus) 101 #define __inline inline /* convert to C++ keyword */ 102 #endif /* !__cplusplus */ 103 104 #else /* !(__STDC__ || __cplusplus) */ 105 #define __P(protos) () /* traditional C preprocessor */ 106 #define __CONCAT(x,y) x/**/y 107 #define __STRING(x) "x" 108 109 #endif /* !(__STDC__ || __cplusplus) */ 110 111 #define __always_inline __attribute__((__always_inline__)) 112 #define __attribute_const__ __attribute__((__const__)) 113 #define __attribute_pure__ __attribute__((__pure__)) 114 #define __dead __attribute__((__noreturn__)) 115 #define __noreturn __attribute__((__noreturn__)) 116 #define __mallocfunc __attribute__((__malloc__)) 117 #define __packed __attribute__((__packed__)) 118 #define __unused __attribute__((__unused__)) 119 #define __used __attribute__((__used__)) 120 121 #define __printflike(x, y) __attribute__((__format__(printf, x, y))) 122 #define __scanflike(x, y) __attribute__((__format__(scanf, x, y))) 123 #define __strftimelike(x) __attribute__((__format__(strftime, x, 0))) 124 125 /* 126 * GNU C version 2.96 added explicit branch prediction so that 127 * the CPU back-end can hint the processor and also so that 128 * code blocks can be reordered such that the predicted path 129 * sees a more linear flow, thus improving cache behavior, etc. 130 * 131 * The following two macros provide us with a way to use this 132 * compiler feature. Use __predict_true() if you expect the expression 133 * to evaluate to true, and __predict_false() if you expect the 134 * expression to evaluate to false. 135 * 136 * A few notes about usage: 137 * 138 * * Generally, __predict_false() error condition checks (unless 139 * you have some _strong_ reason to do otherwise, in which case 140 * document it), and/or __predict_true() `no-error' condition 141 * checks, assuming you want to optimize for the no-error case. 142 * 143 * * Other than that, if you don't know the likelihood of a test 144 * succeeding from empirical or other `hard' evidence, don't 145 * make predictions. 146 * 147 * * These are meant to be used in places that are run `a lot'. 148 * It is wasteful to make predictions in code that is run 149 * seldomly (e.g. at subsystem initialization time) as the 150 * basic block reordering that this affects can often generate 151 * larger code. 152 */ 153 #define __predict_true(exp) __builtin_expect((exp) != 0, 1) 154 #define __predict_false(exp) __builtin_expect((exp) != 0, 0) 155 156 #define __wur __attribute__((__warn_unused_result__)) 157 158 #ifdef __clang__ 159 # define __errorattr(msg) __attribute__((unavailable(msg))) 160 # define __warnattr(msg) __attribute__((deprecated(msg))) 161 # define __warnattr_real(msg) __attribute__((deprecated(msg))) 162 # define __enable_if(cond, msg) __attribute__((enable_if(cond, msg))) 163 # define __clang_error_if(cond, msg) __attribute__((diagnose_if(cond, msg, "error"))) 164 # define __clang_warning_if(cond, msg) __attribute__((diagnose_if(cond, msg, "warning"))) 165 #else 166 # define __errorattr(msg) __attribute__((__error__(msg))) 167 # define __warnattr(msg) __attribute__((__warning__(msg))) 168 # define __warnattr_real __warnattr 169 /* enable_if doesn't exist on other compilers; give an error if it's used. */ 170 /* diagnose_if doesn't exist either, but it's often tagged on non-clang-specific functions */ 171 # define __clang_error_if(cond, msg) 172 # define __clang_warning_if(cond, msg) 173 174 /* errordecls really don't work as well in clang as they do in GCC. */ 175 # define __errordecl(name, msg) extern void name(void) __errorattr(msg) 176 #endif 177 178 #if defined(ANDROID_STRICT) 179 /* 180 * For things that are sketchy, but not necessarily an error. FIXME: Enable 181 * this. 182 */ 183 # define __warnattr_strict(msg) /* __warnattr(msg) */ 184 #else 185 # define __warnattr_strict(msg) 186 #endif 187 188 /* 189 * Some BSD source needs these macros. 190 * Originally they embedded the rcs versions of each source file 191 * in the generated binary. We strip strings during build anyway,. 192 */ 193 #define __IDSTRING(_prefix,_s) /* nothing */ 194 #define __COPYRIGHT(_s) /* nothing */ 195 #define __FBSDID(_s) /* nothing */ 196 #define __RCSID(_s) /* nothing */ 197 #define __SCCSID(_s) /* nothing */ 198 199 /* 200 * With bionic, you always get all C and POSIX API. 201 * 202 * If you want BSD and/or GNU extensions, _BSD_SOURCE and/or _GNU_SOURCE are 203 * expected to be defined by callers before *any* standard header file is 204 * included. 205 * 206 * In our header files we test against __USE_BSD and __USE_GNU. 207 */ 208 #if defined(_GNU_SOURCE) 209 # define __USE_BSD 1 210 # define __USE_GNU 1 211 #endif 212 213 #if defined(_BSD_SOURCE) 214 # define __USE_BSD 1 215 #endif 216 217 /* 218 * _FILE_OFFSET_BITS 64 support. 219 * See https://android.googlesource.com/platform/bionic/+/master/docs/32-bit-abi.md 220 */ 221 #if !defined(__LP64__) && defined(_FILE_OFFSET_BITS) && _FILE_OFFSET_BITS == 64 222 # define __USE_FILE_OFFSET64 1 223 /* 224 * Note that __RENAME_IF_FILE_OFFSET64 is only valid if the off_t and off64_t 225 * functions were both added at the same API level because if you use this, 226 * you only have one declaration to attach __INTRODUCED_IN to. 227 */ 228 # define __RENAME_IF_FILE_OFFSET64(func) __RENAME(func) 229 #else 230 # define __RENAME_IF_FILE_OFFSET64(func) 231 #endif 232 233 /* 234 * For LP32, `long double` == `double`. Historically many `long double` functions were incorrect 235 * on x86, missing on most architectures, and even if they are present and correct, linking to 236 * them just bloats your ELF file by adding extra relocations. The __BIONIC_LP32_USE_LONG_DOUBLE 237 * macro lets us test the headers both ways (and adds an escape valve). 238 * 239 * Note that some functions have their __RENAME_LDBL commented out as a sign that although we could 240 * use __RENAME_LDBL it would actually cause the function to be introduced later because the 241 * `long double` variant appeared before the `double` variant. 242 */ 243 #if defined(__LP64__) || defined(__BIONIC_LP32_USE_LONG_DOUBLE) 244 #define __RENAME_LDBL(rewrite,rewrite_api_level,regular_api_level) __INTRODUCED_IN(regular_api_level) 245 #else 246 #define __RENAME_LDBL(rewrite,rewrite_api_level,regular_api_level) __RENAME(rewrite) __INTRODUCED_IN(rewrite_api_level) 247 #endif 248 249 /* 250 * On all architectures, `struct stat` == `struct stat64`, but LP32 didn't gain the *64 functions 251 * until API level 21. 252 */ 253 #if defined(__LP64__) || defined(__BIONIC_LP32_USE_STAT64) 254 #define __RENAME_STAT64(rewrite,rewrite_api_level,regular_api_level) __INTRODUCED_IN(regular_api_level) 255 #else 256 #define __RENAME_STAT64(rewrite,rewrite_api_level,regular_api_level) __RENAME(rewrite) __INTRODUCED_IN(rewrite_api_level) 257 #endif 258 259 /* glibc compatibility. */ 260 #if defined(__LP64__) 261 #define __WORDSIZE 64 262 #else 263 #define __WORDSIZE 32 264 #endif 265 266 /* 267 * When _FORTIFY_SOURCE is defined, automatic bounds checking is 268 * added to commonly used libc functions. If a buffer overrun is 269 * detected, the program is safely aborted. 270 * 271 * https://android-developers.googleblog.com/2017/04/fortify-in-android.html 272 */ 273 274 #define __BIONIC_FORTIFY_UNKNOWN_SIZE ((size_t) -1) 275 276 #if defined(_FORTIFY_SOURCE) && _FORTIFY_SOURCE > 0 277 # if defined(__clang__) 278 /* 279 * FORTIFY's _chk functions effectively disable ASAN's stdlib interceptors. 280 * Additionally, the static analyzer/clang-tidy try to pattern match some 281 * standard library functions, and FORTIFY sometimes interferes with this. So, 282 * we turn FORTIFY off in both cases. 283 */ 284 # if !__has_feature(address_sanitizer) && !defined(__clang_analyzer__) 285 # define __BIONIC_FORTIFY 1 286 # endif 287 # elif defined(__OPTIMIZE__) && __OPTIMIZE__ > 0 288 # define __BIONIC_FORTIFY 1 289 # endif 290 #endif 291 292 // As we move some FORTIFY checks to be always on, __bos needs to be 293 // always available. 294 #if defined(__BIONIC_FORTIFY) 295 # if _FORTIFY_SOURCE == 2 296 # define __bos_level 1 297 # else 298 # define __bos_level 0 299 # endif 300 #else 301 # define __bos_level 0 302 #endif 303 304 #define __bosn(s, n) __builtin_object_size((s), (n)) 305 #define __bos(s) __bosn((s), __bos_level) 306 307 #if defined(__BIONIC_FORTIFY) 308 # define __bos0(s) __bosn((s), 0) 309 # if defined(__clang__) 310 # define __pass_object_size_n(n) __attribute__((pass_object_size(n))) 311 /* 312 * FORTIFY'ed functions all have either enable_if or pass_object_size, which 313 * makes taking their address impossible. Saying (&read)(foo, bar, baz); will 314 * therefore call the unFORTIFYed version of read. 315 */ 316 # define __call_bypassing_fortify(fn) (&fn) 317 /* 318 * Because clang-FORTIFY uses overloads, we can't mark functions as `extern 319 * inline` without making them available externally. 320 */ 321 # define __BIONIC_FORTIFY_INLINE static __inline__ __always_inline 322 /* 323 * We should use __BIONIC_FORTIFY_VARIADIC instead of __BIONIC_FORTIFY_INLINE 324 * for variadic functions because compilers cannot inline them. 325 * The __always_inline attribute is useless, misleading, and could trigger 326 * clang compiler bug to incorrectly inline variadic functions. 327 */ 328 # define __BIONIC_FORTIFY_VARIADIC static __inline__ 329 /* Error functions don't have bodies, so they can just be static. */ 330 # define __BIONIC_ERROR_FUNCTION_VISIBILITY static 331 # else 332 /* 333 * Where they can, GCC and clang-style FORTIFY share implementations. 334 * So, make these nops in GCC. 335 */ 336 # define __pass_object_size_n(n) 337 # define __call_bypassing_fortify(fn) (fn) 338 /* __BIONIC_FORTIFY_NONSTATIC_INLINE is pointless in GCC's FORTIFY */ 339 # define __BIONIC_FORTIFY_INLINE extern __inline__ __always_inline __attribute__((gnu_inline)) __attribute__((__artificial__)) 340 /* __always_inline is probably okay and ignored by gcc in __BIONIC_FORTIFY_VARIADIC */ 341 # define __BIONIC_FORTIFY_VARIADIC __BIONIC_FORTIFY_INLINE 342 # endif 343 #else 344 /* Further increase sharing for some inline functions */ 345 # define __pass_object_size_n(n) 346 #endif 347 #define __pass_object_size __pass_object_size_n(__bos_level) 348 #define __pass_object_size0 __pass_object_size_n(0) 349 350 #if defined(__BIONIC_FORTIFY) || defined(__BIONIC_DECLARE_FORTIFY_HELPERS) 351 # define __BIONIC_INCLUDE_FORTIFY_HEADERS 1 352 #endif 353 354 /* 355 * Used to support clangisms with FORTIFY. Because these change how symbols are 356 * emitted, we need to ensure that bionic itself is built fortified. But lots 357 * of external code (especially stuff using configure) likes to declare 358 * functions directly, and they can't know that the overloadable attribute 359 * exists. This leads to errors like: 360 * 361 * dcigettext.c:151:7: error: redeclaration of 'getcwd' must have the 'overloadable' attribute 362 * char *getcwd (); 363 * ^ 364 * 365 * To avoid this and keep such software building, don't use overloadable if 366 * we're not using fortify. 367 */ 368 #if defined(__clang__) && defined(__BIONIC_FORTIFY) 369 # define __overloadable __attribute__((overloadable)) 370 #else 371 # define __overloadable 372 #endif 373 374 /* Used to tag non-static symbols that are private and never exposed by the shared library. */ 375 #define __LIBC_HIDDEN__ __attribute__((visibility("hidden"))) 376 377 /* 378 * Used to tag symbols that should be hidden for 64-bit, 379 * but visible to preserve binary compatibility for LP32. 380 */ 381 #ifdef __LP64__ 382 #define __LIBC32_LEGACY_PUBLIC__ __attribute__((visibility("hidden"))) 383 #else 384 #define __LIBC32_LEGACY_PUBLIC__ __attribute__((visibility("default"))) 385 #endif 386 387 /* Used to rename functions so that the compiler emits a call to 'x' rather than the function this was applied to. */ 388 #define __RENAME(x) __asm__(#x) 389 390 #if __has_builtin(__builtin_umul_overflow) || __GNUC__ >= 5 391 #if defined(__LP64__) 392 #define __size_mul_overflow(a, b, result) __builtin_umull_overflow(a, b, result) 393 #else 394 #define __size_mul_overflow(a, b, result) __builtin_umul_overflow(a, b, result) 395 #endif 396 #else 397 extern __inline__ __always_inline __attribute__((gnu_inline)) 398 int __size_mul_overflow(__SIZE_TYPE__ a, __SIZE_TYPE__ b, __SIZE_TYPE__ *result) { 399 *result = a * b; 400 static const __SIZE_TYPE__ mul_no_overflow = 1UL << (sizeof(__SIZE_TYPE__) * 4); 401 return (a >= mul_no_overflow || b >= mul_no_overflow) && a > 0 && (__SIZE_TYPE__)-1 / a < b; 402 } 403 #endif 404 405 #if defined(__clang__) 406 /* 407 * Used when we need to check for overflow when multiplying x and y. This 408 * should only be used where __size_mul_overflow can not work, because it makes 409 * assumptions that __size_mul_overflow doesn't (x and y are positive, ...), 410 * *and* doesn't make use of compiler intrinsics, so it's probably slower than 411 * __size_mul_overflow. 412 */ 413 #define __unsafe_check_mul_overflow(x, y) ((__SIZE_TYPE__)-1 / (x) < (y)) 414 #endif 415 416 #endif /* !_SYS_CDEFS_H_ */ 417
