src/basic/macro.h

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 #pragma once
   4
   5 /***
   6   This file is part of systemd.
   7
   8   Copyright 2010 Lennart Poettering
   9
  10   systemd is free software; you can redistribute it and/or modify it
  11   under the terms of the GNU Lesser General Public License as published by
  12   the Free Software Foundation; either version 2.1 of the License, or
  13   (at your option) any later version.
  14
  15   systemd is distributed in the hope that it will be useful, but
  16   WITHOUT ANY WARRANTY; without even the implied warranty of
  17   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  18   Lesser General Public License for more details.
  19
  20   You should have received a copy of the GNU Lesser General Public License
  21   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  22 ***/
  23
  24 #include <assert.h>
  25 #include <sys/param.h>
  26 #include <sys/types.h>
  27 #include <sys/uio.h>
  28 #include <inttypes.h>
  29 #include <stdbool.h>
  30
  31 #define _printf_(a,b) __attribute__ ((format (printf, a, b)))
  32 #define _alloc_(...) __attribute__ ((alloc_size(__VA_ARGS__)))
  33 #define _sentinel_ __attribute__ ((sentinel))
  34 #define _unused_ __attribute__ ((unused))
  35 #define _destructor_ __attribute__ ((destructor))
  36 #define _pure_ __attribute__ ((pure))
  37 #define _const_ __attribute__ ((const))
  38 #define _deprecated_ __attribute__ ((deprecated))
  39 #define _packed_ __attribute__ ((packed))
  40 #define _malloc_ __attribute__ ((malloc))
  41 #define _weak_ __attribute__ ((weak))
  42 #define _likely_(x) (__builtin_expect(!!(x),1))
  43 #define _unlikely_(x) (__builtin_expect(!!(x),0))
  44 #define _public_ __attribute__ ((visibility("default")))
  45 #define _hidden_ __attribute__ ((visibility("hidden")))
  46 #define _weakref_(x) __attribute__((weakref(#x)))
  47 #define _alignas_(x) __attribute__((aligned(__alignof(x))))
  48 #define _cleanup_(x) __attribute__((cleanup(x)))
  49
  50 /* Temporarily disable some warnings */
  51 #define DISABLE_WARNING_DECLARATION_AFTER_STATEMENT                     \
  52         _Pragma("GCC diagnostic push");                                 \
  53         _Pragma("GCC diagnostic ignored \"-Wdeclaration-after-statement\"")
  54
  55 #define DISABLE_WARNING_FORMAT_NONLITERAL                               \
  56         _Pragma("GCC diagnostic push");                                 \
  57         _Pragma("GCC diagnostic ignored \"-Wformat-nonliteral\"")
  58
  59 #define DISABLE_WARNING_MISSING_PROTOTYPES                              \
  60         _Pragma("GCC diagnostic push");                                 \
  61         _Pragma("GCC diagnostic ignored \"-Wmissing-prototypes\"")
  62
  63 #define DISABLE_WARNING_NONNULL                                         \
  64         _Pragma("GCC diagnostic push");                                 \
  65         _Pragma("GCC diagnostic ignored \"-Wnonnull\"")
  66
  67 #define DISABLE_WARNING_SHADOW                                          \
  68         _Pragma("GCC diagnostic push");                                 \
  69         _Pragma("GCC diagnostic ignored \"-Wshadow\"")
  70
  71 #define DISABLE_WARNING_INCOMPATIBLE_POINTER_TYPES                      \
  72         _Pragma("GCC diagnostic push");                                 \
  73         _Pragma("GCC diagnostic ignored \"-Wincompatible-pointer-types\"")
  74
  75 #define REENABLE_WARNING                                                \
  76         _Pragma("GCC diagnostic pop")
  77
  78 /* automake test harness */
  79 #define EXIT_TEST_SKIP 77
  80
  81 #define XSTRINGIFY(x) #x
  82 #define STRINGIFY(x) XSTRINGIFY(x)
  83
  84 #define XCONCATENATE(x, y) x ## y
  85 #define CONCATENATE(x, y) XCONCATENATE(x, y)
  86
  87 #define UNIQ_T(x, uniq) CONCATENATE(__unique_prefix_, CONCATENATE(x, uniq))
  88 #define UNIQ __COUNTER__
  89
  90 /* Rounds up */
  91
  92 #define ALIGN4(l) (((l) + 3) & ~3)
  93 #define ALIGN8(l) (((l) + 7) & ~7)
  94
  95 #if __SIZEOF_POINTER__ == 8
  96 #define ALIGN(l) ALIGN8(l)
  97 #elif __SIZEOF_POINTER__ == 4
  98 #define ALIGN(l) ALIGN4(l)
  99 #else
 100 #error "Wut? Pointers are neither 4 nor 8 bytes long?"
 101 #endif
 102
 103 #define ALIGN_PTR(p) ((void*) ALIGN((unsigned long) (p)))
 104 #define ALIGN4_PTR(p) ((void*) ALIGN4((unsigned long) (p)))
 105 #define ALIGN8_PTR(p) ((void*) ALIGN8((unsigned long) (p)))
 106
 107 static inline size_t ALIGN_TO(size_t l, size_t ali) {
 108         return ((l + ali - 1) & ~(ali - 1));
 109 }
 110
 111 #define ALIGN_TO_PTR(p, ali) ((void*) ALIGN_TO((unsigned long) (p), (ali)))
 112
 113 /* align to next higher power-of-2 (except for: 0 => 0, overflow => 0) */
 114 static inline unsigned long ALIGN_POWER2(unsigned long u) {
 115         /* clz(0) is undefined */
 116         if (u == 1)
 117                 return 1;
 118
 119         /* left-shift overflow is undefined */
 120         if (__builtin_clzl(u - 1UL) < 1)
 121                 return 0;
 122
 123         return 1UL << (sizeof(u) * 8 - __builtin_clzl(u - 1UL));
 124 }
 125
 126 #define ELEMENTSOF(x) (sizeof(x)/sizeof((x)[0]))
 127
 128 /*
 129  * container_of - cast a member of a structure out to the containing structure
 130  * @ptr: the pointer to the member.
 131  * @type: the type of the container struct this is embedded in.
 132  * @member: the name of the member within the struct.
 133  */
 134 #define container_of(ptr, type, member) __container_of(UNIQ, (ptr), type, member)
 135 #define __container_of(uniq, ptr, type, member)                         \
 136         __extension__ ({                                                \
 137                 const typeof( ((type*)0)->member ) *UNIQ_T(A, uniq) = (ptr); \
 138                 (type*)( (char *)UNIQ_T(A, uniq) - offsetof(type,member) ); \
 139         })
 140
 141 #undef MAX
 142 #define MAX(a, b) __MAX(UNIQ, (a), UNIQ, (b))
 143 #define __MAX(aq, a, bq, b)                             \
 144         __extension__ ({                                \
 145                 const typeof(a) UNIQ_T(A, aq) = (a);    \
 146                 const typeof(b) UNIQ_T(B, bq) = (b);    \
 147                 UNIQ_T(A,aq) > UNIQ_T(B,bq) ? UNIQ_T(A,aq) : UNIQ_T(B,bq); \
 148         })
 149
 150 /* evaluates to (void) if _A or _B are not constant or of different types */
 151 #define CONST_MAX(_A, _B) \
 152         __extension__ (__builtin_choose_expr(                           \
 153                 __builtin_constant_p(_A) &&                             \
 154                 __builtin_constant_p(_B) &&                             \
 155                 __builtin_types_compatible_p(typeof(_A), typeof(_B)),   \
 156                 ((_A) > (_B)) ? (_A) : (_B),                            \
 157                 (void)0))
 158
 159 /* takes two types and returns the size of the larger one */
 160 #define MAXSIZE(A, B) (sizeof(union _packed_ { typeof(A) a; typeof(B) b; }))
 161
 162 #define MAX3(x,y,z)                                     \
 163         __extension__ ({                                \
 164                         const typeof(x) _c = MAX(x,y);  \
 165                         MAX(_c, z);                     \
 166                 })
 167
 168 #undef MIN
 169 #define MIN(a, b) __MIN(UNIQ, (a), UNIQ, (b))
 170 #define __MIN(aq, a, bq, b)                             \
 171         __extension__ ({                                \
 172                 const typeof(a) UNIQ_T(A, aq) = (a);    \
 173                 const typeof(b) UNIQ_T(B, bq) = (b);    \
 174                 UNIQ_T(A,aq) < UNIQ_T(B,bq) ? UNIQ_T(A,aq) : UNIQ_T(B,bq); \
 175         })
 176
 177 #define MIN3(x,y,z)                                     \
 178         __extension__ ({                                \
 179                         const typeof(x) _c = MIN(x,y);  \
 180                         MIN(_c, z);                     \
 181                 })
 182
 183 #define LESS_BY(a, b) __LESS_BY(UNIQ, (a), UNIQ, (b))
 184 #define __LESS_BY(aq, a, bq, b)                         \
 185         __extension__ ({                                \
 186                 const typeof(a) UNIQ_T(A, aq) = (a);    \
 187                 const typeof(b) UNIQ_T(B, bq) = (b);    \
 188                 UNIQ_T(A,aq) > UNIQ_T(B,bq) ? UNIQ_T(A,aq) - UNIQ_T(B,bq) : 0; \
 189         })
 190
 191 #undef CLAMP
 192 #define CLAMP(x, low, high) __CLAMP(UNIQ, (x), UNIQ, (low), UNIQ, (high))
 193 #define __CLAMP(xq, x, lowq, low, highq, high)                          \
 194         __extension__ ({                                                \
 195                 const typeof(x) UNIQ_T(X,xq) = (x);                     \
 196                 const typeof(low) UNIQ_T(LOW,lowq) = (low);             \
 197                 const typeof(high) UNIQ_T(HIGH,highq) = (high);         \
 198                         UNIQ_T(X,xq) > UNIQ_T(HIGH,highq) ?             \
 199                                 UNIQ_T(HIGH,highq) :                    \
 200                                 UNIQ_T(X,xq) < UNIQ_T(LOW,lowq) ?       \
 201                                         UNIQ_T(LOW,lowq) :              \
 202                                         UNIQ_T(X,xq);                   \
 203         })
 204
 205 /* [(x + y - 1) / y] suffers from an integer overflow, even though the
 206  * computation should be possible in the given type. Therefore, we use
 207  * [x / y + !!(x % y)]. Note that on "Real CPUs" a division returns both the
 208  * quotient and the remainder, so both should be equally fast. */
 209 #define DIV_ROUND_UP(_x, _y)                                            \
 210         __extension__ ({                                                \
 211                 const typeof(_x) __x = (_x);                            \
 212                 const typeof(_y) __y = (_y);                            \
 213                 (__x / __y + !!(__x % __y));                            \
 214         })
 215
 216 #define assert_se(expr)                                                 \
 217         do {                                                            \
 218                 if (_unlikely_(!(expr)))                                \
 219                         log_assert_failed(#expr, __FILE__, __LINE__, __PRETTY_FUNCTION__); \
 220         } while (false)                                                 \
 221
 222 /* We override the glibc assert() here. */
 223 #undef assert
 224 #ifdef NDEBUG
 225 #define assert(expr) do {} while(false)
 226 #else
 227 #define assert(expr) assert_se(expr)
 228 #endif
 229
 230 #define assert_not_reached(t)                                           \
 231         do {                                                            \
 232                 log_assert_failed_unreachable(t, __FILE__, __LINE__, __PRETTY_FUNCTION__); \
 233         } while (false)
 234
 235 #if defined(static_assert)
 236 /* static_assert() is sometimes defined in a way that trips up
 237  * -Wdeclaration-after-statement, hence let's temporarily turn off
 238  * this warning around it. */
 239 #define assert_cc(expr)                                                 \
 240         DISABLE_WARNING_DECLARATION_AFTER_STATEMENT;                    \
 241         static_assert(expr, #expr);                                     \
 242         REENABLE_WARNING
 243 #else
 244 #define assert_cc(expr)                                                 \
 245         DISABLE_WARNING_DECLARATION_AFTER_STATEMENT;                    \
 246         struct CONCATENATE(_assert_struct_, __COUNTER__) {              \
 247                 char x[(expr) ? 0 : -1];                                \
 248         };                                                              \
 249         REENABLE_WARNING
 250 #endif
 251
 252 #define assert_log(expr) ((_likely_(expr))      \
 253         ? (true)                                \
 254         : (log_assert_failed_return(#expr, __FILE__, __LINE__, __PRETTY_FUNCTION__), false))
 255
 256 #define assert_return(expr, r)                                          \
 257         do {                                                            \
 258                 if (!assert_log(expr))                                  \
 259                         return (r);                                     \
 260         } while (false)
 261
 262 #define assert_return_errno(expr, r, err)                               \
 263         do {                                                            \
 264                 if (!assert_log(expr)) {                                \
 265                         errno = err;                                    \
 266                         return (r);                                     \
 267                 }                                                       \
 268         } while (false)
 269
 270 #define PTR_TO_INT(p) ((int) ((intptr_t) (p)))
 271 #define INT_TO_PTR(u) ((void *) ((intptr_t) (u)))
 272 #define PTR_TO_UINT(p) ((unsigned int) ((uintptr_t) (p)))
 273 #define UINT_TO_PTR(u) ((void *) ((uintptr_t) (u)))
 274
 275 #define PTR_TO_LONG(p) ((long) ((intptr_t) (p)))
 276 #define LONG_TO_PTR(u) ((void *) ((intptr_t) (u)))
 277 #define PTR_TO_ULONG(p) ((unsigned long) ((uintptr_t) (p)))
 278 #define ULONG_TO_PTR(u) ((void *) ((uintptr_t) (u)))
 279
 280 #define PTR_TO_INT32(p) ((int32_t) ((intptr_t) (p)))
 281 #define INT32_TO_PTR(u) ((void *) ((intptr_t) (u)))
 282 #define PTR_TO_UINT32(p) ((uint32_t) ((uintptr_t) (p)))
 283 #define UINT32_TO_PTR(u) ((void *) ((uintptr_t) (u)))
 284
 285 #define PTR_TO_INT64(p) ((int64_t) ((intptr_t) (p)))
 286 #define INT64_TO_PTR(u) ((void *) ((intptr_t) (u)))
 287 #define PTR_TO_UINT64(p) ((uint64_t) ((uintptr_t) (p)))
 288 #define UINT64_TO_PTR(u) ((void *) ((uintptr_t) (u)))
 289
 290 #define PTR_TO_SIZE(p) ((size_t) ((uintptr_t) (p)))
 291 #define SIZE_TO_PTR(u) ((void *) ((uintptr_t) (u)))
 292
 293 /* The following macros add 1 when converting things, since UID 0 is a
 294  * valid UID, while the pointer NULL is special */
 295 #define PTR_TO_UID(p) ((uid_t) (((uintptr_t) (p))-1))
 296 #define UID_TO_PTR(u) ((void*) (((uintptr_t) (u))+1))
 297
 298 #define PTR_TO_GID(p) ((gid_t) (((uintptr_t) (p))-1))
 299 #define GID_TO_PTR(u) ((void*) (((uintptr_t) (u))+1))
 300
 301 #define PTR_TO_PID(p) ((pid_t) ((uintptr_t) p))
 302 #define PID_TO_PTR(p) ((void*) ((uintptr_t) p))
 303
 304 #define memzero(x,l) (memset((x), 0, (l)))
 305 #define zero(x) (memzero(&(x), sizeof(x)))
 306
 307 #define CHAR_TO_STR(x) ((char[2]) { x, 0 })
 308
 309 #define char_array_0(x) x[sizeof(x)-1] = 0;
 310
 311 #define IOVEC_SET_STRING(i, s)                  \
 312         do {                                    \
 313                 struct iovec *_i = &(i);        \
 314                 char *_s = (char *)(s);         \
 315                 _i->iov_base = _s;              \
 316                 _i->iov_len = strlen(_s);       \
 317         } while(false)
 318
 319 static inline size_t IOVEC_TOTAL_SIZE(const struct iovec *i, unsigned n) {
 320         unsigned j;
 321         size_t r = 0;
 322
 323         for (j = 0; j < n; j++)
 324                 r += i[j].iov_len;
 325
 326         return r;
 327 }
 328
 329 static inline size_t IOVEC_INCREMENT(struct iovec *i, unsigned n, size_t k) {
 330         unsigned j;
 331
 332         for (j = 0; j < n; j++) {
 333                 size_t sub;
 334
 335                 if (_unlikely_(k <= 0))
 336                         break;
 337
 338                 sub = MIN(i[j].iov_len, k);
 339                 i[j].iov_len -= sub;
 340                 i[j].iov_base = (uint8_t*) i[j].iov_base + sub;
 341                 k -= sub;
 342         }
 343
 344         return k;
 345 }
 346
 347 #define VA_FORMAT_ADVANCE(format, ap)                                   \
 348 do {                                                                    \
 349         int _argtypes[128];                                             \
 350         size_t _i, _k;                                                  \
 351         _k = parse_printf_format((format), ELEMENTSOF(_argtypes), _argtypes); \
 352         assert(_k < ELEMENTSOF(_argtypes));                             \
 353         for (_i = 0; _i < _k; _i++) {                                   \
 354                 if (_argtypes[_i] & PA_FLAG_PTR)  {                     \
 355                         (void) va_arg(ap, void*);                       \
 356                         continue;                                       \
 357                 }                                                       \
 358                                                                         \
 359                 switch (_argtypes[_i]) {                                \
 360                 case PA_INT:                                            \
 361                 case PA_INT|PA_FLAG_SHORT:                              \
 362                 case PA_CHAR:                                           \
 363                         (void) va_arg(ap, int);                         \
 364                         break;                                          \
 365                 case PA_INT|PA_FLAG_LONG:                               \
 366                         (void) va_arg(ap, long int);                    \
 367                         break;                                          \
 368                 case PA_INT|PA_FLAG_LONG_LONG:                          \
 369                         (void) va_arg(ap, long long int);               \
 370                         break;                                          \
 371                 case PA_WCHAR:                                          \
 372                         (void) va_arg(ap, wchar_t);                     \
 373                         break;                                          \
 374                 case PA_WSTRING:                                        \
 375                 case PA_STRING:                                         \
 376                 case PA_POINTER:                                        \
 377                         (void) va_arg(ap, void*);                       \
 378                         break;                                          \
 379                 case PA_FLOAT:                                          \
 380                 case PA_DOUBLE:                                         \
 381                         (void) va_arg(ap, double);                      \
 382                         break;                                          \
 383                 case PA_DOUBLE|PA_FLAG_LONG_DOUBLE:                     \
 384                         (void) va_arg(ap, long double);                 \
 385                         break;                                          \
 386                 default:                                                \
 387                         assert_not_reached("Unknown format string argument."); \
 388                 }                                                       \
 389         }                                                               \
 390 } while(false)
 391
 392  /* Because statfs.t_type can be int on some architectures, we have to cast
 393   * the const magic to the type, otherwise the compiler warns about
 394   * signed/unsigned comparison, because the magic can be 32 bit unsigned.
 395  */
 396 #define F_TYPE_EQUAL(a, b) (a == (typeof(a)) b)
 397
 398 /* Returns the number of chars needed to format variables of the
 399  * specified type as a decimal string. Adds in extra space for a
 400  * negative '-' prefix (hence works correctly on signed
 401  * types). Includes space for the trailing NUL. */
 402 #define DECIMAL_STR_MAX(type)                                           \
 403         (2+(sizeof(type) <= 1 ? 3 :                                     \
 404             sizeof(type) <= 2 ? 5 :                                     \
 405             sizeof(type) <= 4 ? 10 :                                    \
 406             sizeof(type) <= 8 ? 20 : sizeof(int[-2*(sizeof(type) > 8)])))
 407
 408 #define SET_FLAG(v, flag, b) \
 409         (v) = (b) ? ((v) | (flag)) : ((v) & ~(flag))
 410
 411 #define IN_SET(x, y, ...)                                               \
 412         ({                                                              \
 413                 static const typeof(y) _array[] = { (y), __VA_ARGS__ }; \
 414                 const typeof(y) _x = (x);                               \
 415                 unsigned _i;                                            \
 416                 bool _found = false;                                    \
 417                 for (_i = 0; _i < ELEMENTSOF(_array); _i++)             \
 418                         if (_array[_i] == _x) {                         \
 419                                 _found = true;                          \
 420                                 break;                                  \
 421                         }                                               \
 422                 _found;                                                 \
 423         })
 424
 425 /* Return a nulstr for a standard cascade of configuration directories,
 426  * suitable to pass to conf_files_list_nulstr or config_parse_many. */
 427 #define CONF_DIRS_NULSTR(n) \
 428         "/etc/" n ".d\0" \
 429         "/run/" n ".d\0" \
 430         "/usr/local/lib/" n ".d\0" \
 431         "/usr/lib/" n ".d\0" \
 432         CONF_DIR_SPLIT_USR(n)
 433
 434 #ifdef HAVE_SPLIT_USR
 435 #define CONF_DIR_SPLIT_USR(n) "/lib/" n ".d\0"
 436 #else
 437 #define CONF_DIR_SPLIT_USR(n)
 438 #endif
 439
 440 /* Define C11 thread_local attribute even on older gcc compiler
 441  * version */
 442 #ifndef thread_local
 443 /*
 444  * Don't break on glibc < 2.16 that doesn't define __STDC_NO_THREADS__
 445  * see http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53769
 446  */
 447 #if __STDC_VERSION__ >= 201112L && !(defined(__STDC_NO_THREADS__) || (defined(__GNU_LIBRARY__) && __GLIBC__ == 2 && __GLIBC_MINOR__ < 16))
 448 #define thread_local _Thread_local
 449 #else
 450 #define thread_local __thread
 451 #endif
 452 #endif
 453
 454 /* Define C11 noreturn without <stdnoreturn.h> and even on older gcc
 455  * compiler versions */
 456 #ifndef noreturn
 457 #if __STDC_VERSION__ >= 201112L
 458 #define noreturn _Noreturn
 459 #else
 460 #define noreturn __attribute__((noreturn))
 461 #endif
 462 #endif
 463
 464 #define UID_INVALID ((uid_t) -1)
 465 #define GID_INVALID ((gid_t) -1)
 466 #define MODE_INVALID ((mode_t) -1)
 467
 468 static inline bool UID_IS_INVALID(uid_t uid) {
 469         /* We consider both the old 16bit -1 user and the newer 32bit
 470          * -1 user invalid, since they are or used to be incompatible
 471          * with syscalls such as setresuid() or chown(). */
 472
 473         return uid == (uid_t) ((uint32_t) -1) || uid == (uid_t) ((uint16_t) -1);
 474 }
 475
 476 static inline bool GID_IS_INVALID(gid_t gid) {
 477         return gid == (gid_t) ((uint32_t) -1) || gid == (gid_t) ((uint16_t) -1);
 478 }
 479
 480 #define DEFINE_TRIVIAL_CLEANUP_FUNC(type, func)                 \
 481         static inline void func##p(type *p) {                   \
 482                 if (*p)                                         \
 483                         func(*p);                               \
 484         }                                                       \
 485         struct __useless_struct_to_allow_trailing_semicolon__
 486
 487 #define CMSG_FOREACH(cmsg, mh)                                          \
 488         for ((cmsg) = CMSG_FIRSTHDR(mh); (cmsg); (cmsg) = CMSG_NXTHDR((mh), (cmsg)))
 489
 490 #include "log.h"