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/sysmacros.h>
  27 #include <sys/types.h>
  28 #include <sys/uio.h>
  29 #include <inttypes.h>
  30 #include <stdbool.h>
  31
  32 #define _printf_(a,b) __attribute__ ((format (printf, a, b)))
  33 #define _alloc_(...) __attribute__ ((alloc_size(__VA_ARGS__)))
  34 #define _sentinel_ __attribute__ ((sentinel))
  35 #define _unused_ __attribute__ ((unused))
  36 #define _destructor_ __attribute__ ((destructor))
  37 #define _pure_ __attribute__ ((pure))
  38 #define _const_ __attribute__ ((const))
  39 #define _deprecated_ __attribute__ ((deprecated))
  40 #define _packed_ __attribute__ ((packed))
  41 #define _malloc_ __attribute__ ((malloc))
  42 #define _weak_ __attribute__ ((weak))
  43 #define _likely_(x) (__builtin_expect(!!(x),1))
  44 #define _unlikely_(x) (__builtin_expect(!!(x),0))
  45 #define _public_ __attribute__ ((visibility("default")))
  46 #define _hidden_ __attribute__ ((visibility("hidden")))
  47 #define _weakref_(x) __attribute__((weakref(#x)))
  48 #define _alignas_(x) __attribute__((aligned(__alignof(x))))
  49 #define _cleanup_(x) __attribute__((cleanup(x)))
  50
  51 /* Temporarily disable some warnings */
  52 #define DISABLE_WARNING_DECLARATION_AFTER_STATEMENT                     \
  53         _Pragma("GCC diagnostic push");                                 \
  54         _Pragma("GCC diagnostic ignored \"-Wdeclaration-after-statement\"")
  55
  56 #define DISABLE_WARNING_FORMAT_NONLITERAL                               \
  57         _Pragma("GCC diagnostic push");                                 \
  58         _Pragma("GCC diagnostic ignored \"-Wformat-nonliteral\"")
  59
  60 #define DISABLE_WARNING_MISSING_PROTOTYPES                              \
  61         _Pragma("GCC diagnostic push");                                 \
  62         _Pragma("GCC diagnostic ignored \"-Wmissing-prototypes\"")
  63
  64 #define DISABLE_WARNING_NONNULL                                         \
  65         _Pragma("GCC diagnostic push");                                 \
  66         _Pragma("GCC diagnostic ignored \"-Wnonnull\"")
  67
  68 #define DISABLE_WARNING_SHADOW                                          \
  69         _Pragma("GCC diagnostic push");                                 \
  70         _Pragma("GCC diagnostic ignored \"-Wshadow\"")
  71
  72 #define DISABLE_WARNING_INCOMPATIBLE_POINTER_TYPES                      \
  73         _Pragma("GCC diagnostic push");                                 \
  74         _Pragma("GCC diagnostic ignored \"-Wincompatible-pointer-types\"")
  75
  76 #define REENABLE_WARNING                                                \
  77         _Pragma("GCC diagnostic pop")
  78
  79 /* automake test harness */
  80 #define EXIT_TEST_SKIP 77
  81
  82 #define XSTRINGIFY(x) #x
  83 #define STRINGIFY(x) XSTRINGIFY(x)
  84
  85 #define XCONCATENATE(x, y) x ## y
  86 #define CONCATENATE(x, y) XCONCATENATE(x, y)
  87
  88 #define UNIQ_T(x, uniq) CONCATENATE(__unique_prefix_, CONCATENATE(x, uniq))
  89 #define UNIQ __COUNTER__
  90
  91 /* Rounds up */
  92
  93 #define ALIGN4(l) (((l) + 3) & ~3)
  94 #define ALIGN8(l) (((l) + 7) & ~7)
  95
  96 #if __SIZEOF_POINTER__ == 8
  97 #define ALIGN(l) ALIGN8(l)
  98 #elif __SIZEOF_POINTER__ == 4
  99 #define ALIGN(l) ALIGN4(l)
 100 #else
 101 #error "Wut? Pointers are neither 4 nor 8 bytes long?"
 102 #endif
 103
 104 #define ALIGN_PTR(p) ((void*) ALIGN((unsigned long) (p)))
 105 #define ALIGN4_PTR(p) ((void*) ALIGN4((unsigned long) (p)))
 106 #define ALIGN8_PTR(p) ((void*) ALIGN8((unsigned long) (p)))
 107
 108 static inline size_t ALIGN_TO(size_t l, size_t ali) {
 109         return ((l + ali - 1) & ~(ali - 1));
 110 }
 111
 112 #define ALIGN_TO_PTR(p, ali) ((void*) ALIGN_TO((unsigned long) (p), (ali)))
 113
 114 /* align to next higher power-of-2 (except for: 0 => 0, overflow => 0) */
 115 static inline unsigned long ALIGN_POWER2(unsigned long u) {
 116         /* clz(0) is undefined */
 117         if (u == 1)
 118                 return 1;
 119
 120         /* left-shift overflow is undefined */
 121         if (__builtin_clzl(u - 1UL) < 1)
 122                 return 0;
 123
 124         return 1UL << (sizeof(u) * 8 - __builtin_clzl(u - 1UL));
 125 }
 126
 127 #define ELEMENTSOF(x) (sizeof(x)/sizeof((x)[0]))
 128
 129 /*
 130  * container_of - cast a member of a structure out to the containing structure
 131  * @ptr: the pointer to the member.
 132  * @type: the type of the container struct this is embedded in.
 133  * @member: the name of the member within the struct.
 134  */
 135 #define container_of(ptr, type, member) __container_of(UNIQ, (ptr), type, member)
 136 #define __container_of(uniq, ptr, type, member)                         \
 137         __extension__ ({                                                \
 138                 const typeof( ((type*)0)->member ) *UNIQ_T(A, uniq) = (ptr); \
 139                 (type*)( (char *)UNIQ_T(A, uniq) - offsetof(type,member) ); \
 140         })
 141
 142 #undef MAX
 143 #define MAX(a, b) __MAX(UNIQ, (a), UNIQ, (b))
 144 #define __MAX(aq, a, bq, b)                             \
 145         __extension__ ({                                \
 146                 const typeof(a) UNIQ_T(A, aq) = (a);    \
 147                 const typeof(b) UNIQ_T(B, bq) = (b);    \
 148                 UNIQ_T(A,aq) > UNIQ_T(B,bq) ? UNIQ_T(A,aq) : UNIQ_T(B,bq); \
 149         })
 150
 151 /* evaluates to (void) if _A or _B are not constant or of different types */
 152 #define CONST_MAX(_A, _B) \
 153         __extension__ (__builtin_choose_expr(                           \
 154                 __builtin_constant_p(_A) &&                             \
 155                 __builtin_constant_p(_B) &&                             \
 156                 __builtin_types_compatible_p(typeof(_A), typeof(_B)),   \
 157                 ((_A) > (_B)) ? (_A) : (_B),                            \
 158                 (void)0))
 159
 160 /* takes two types and returns the size of the larger one */
 161 #define MAXSIZE(A, B) (sizeof(union _packed_ { typeof(A) a; typeof(B) b; }))
 162
 163 #define MAX3(x,y,z)                                     \
 164         __extension__ ({                                \
 165                         const typeof(x) _c = MAX(x,y);  \
 166                         MAX(_c, z);                     \
 167                 })
 168
 169 #undef MIN
 170 #define MIN(a, b) __MIN(UNIQ, (a), UNIQ, (b))
 171 #define __MIN(aq, a, bq, b)                             \
 172         __extension__ ({                                \
 173                 const typeof(a) UNIQ_T(A, aq) = (a);    \
 174                 const typeof(b) UNIQ_T(B, bq) = (b);    \
 175                 UNIQ_T(A,aq) < UNIQ_T(B,bq) ? UNIQ_T(A,aq) : UNIQ_T(B,bq); \
 176         })
 177
 178 #define MIN3(x,y,z)                                     \
 179         __extension__ ({                                \
 180                         const typeof(x) _c = MIN(x,y);  \
 181                         MIN(_c, z);                     \
 182                 })
 183
 184 #define LESS_BY(a, b) __LESS_BY(UNIQ, (a), UNIQ, (b))
 185 #define __LESS_BY(aq, a, bq, b)                         \
 186         __extension__ ({                                \
 187                 const typeof(a) UNIQ_T(A, aq) = (a);    \
 188                 const typeof(b) UNIQ_T(B, bq) = (b);    \
 189                 UNIQ_T(A,aq) > UNIQ_T(B,bq) ? UNIQ_T(A,aq) - UNIQ_T(B,bq) : 0; \
 190         })
 191
 192 #undef CLAMP
 193 #define CLAMP(x, low, high) __CLAMP(UNIQ, (x), UNIQ, (low), UNIQ, (high))
 194 #define __CLAMP(xq, x, lowq, low, highq, high)                          \
 195         __extension__ ({                                                \
 196                 const typeof(x) UNIQ_T(X,xq) = (x);                     \
 197                 const typeof(low) UNIQ_T(LOW,lowq) = (low);             \
 198                 const typeof(high) UNIQ_T(HIGH,highq) = (high);         \
 199                         UNIQ_T(X,xq) > UNIQ_T(HIGH,highq) ?             \
 200                                 UNIQ_T(HIGH,highq) :                    \
 201                                 UNIQ_T(X,xq) < UNIQ_T(LOW,lowq) ?       \
 202                                         UNIQ_T(LOW,lowq) :              \
 203                                         UNIQ_T(X,xq);                   \
 204         })
 205
 206 /* [(x + y - 1) / y] suffers from an integer overflow, even though the
 207  * computation should be possible in the given type. Therefore, we use
 208  * [x / y + !!(x % y)]. Note that on "Real CPUs" a division returns both the
 209  * quotient and the remainder, so both should be equally fast. */
 210 #define DIV_ROUND_UP(_x, _y)                                            \
 211         __extension__ ({                                                \
 212                 const typeof(_x) __x = (_x);                            \
 213                 const typeof(_y) __y = (_y);                            \
 214                 (__x / __y + !!(__x % __y));                            \
 215         })
 216
 217 #define assert_message_se(expr, message)                                \
 218         do {                                                            \
 219                 if (_unlikely_(!(expr)))                                \
 220                         log_assert_failed(message, __FILE__, __LINE__, __PRETTY_FUNCTION__); \
 221         } while (false)
 222
 223 #define assert_se(expr) assert_message_se(expr, #expr)
 224
 225 /* We override the glibc assert() here. */
 226 #undef assert
 227 #ifdef NDEBUG
 228 #define assert(expr) do {} while(false)
 229 #else
 230 #define assert(expr) assert_message_se(expr, #expr)
 231 #endif
 232
 233 #define assert_not_reached(t)                                           \
 234         do {                                                            \
 235                 log_assert_failed_unreachable(t, __FILE__, __LINE__, __PRETTY_FUNCTION__); \
 236         } while (false)
 237
 238 #if defined(static_assert)
 239 /* static_assert() is sometimes defined in a way that trips up
 240  * -Wdeclaration-after-statement, hence let's temporarily turn off
 241  * this warning around it. */
 242 #define assert_cc(expr)                                                 \
 243         DISABLE_WARNING_DECLARATION_AFTER_STATEMENT;                    \
 244         static_assert(expr, #expr);                                     \
 245         REENABLE_WARNING
 246 #else
 247 #define assert_cc(expr)                                                 \
 248         DISABLE_WARNING_DECLARATION_AFTER_STATEMENT;                    \
 249         struct CONCATENATE(_assert_struct_, __COUNTER__) {              \
 250                 char x[(expr) ? 0 : -1];                                \
 251         };                                                              \
 252         REENABLE_WARNING
 253 #endif
 254
 255 #define assert_log(expr, message) ((_likely_(expr))                     \
 256         ? (true)                                                        \
 257         : (log_assert_failed_return(message, __FILE__, __LINE__, __PRETTY_FUNCTION__), false))
 258
 259 #define assert_return(expr, r)                                          \
 260         do {                                                            \
 261                 if (!assert_log(expr, #expr))                           \
 262                         return (r);                                     \
 263         } while (false)
 264
 265 #define assert_return_errno(expr, r, err)                               \
 266         do {                                                            \
 267                 if (!assert_log(expr, #expr)) {                         \
 268                         errno = err;                                    \
 269                         return (r);                                     \
 270                 }                                                       \
 271         } while (false)
 272
 273 #define PTR_TO_INT(p) ((int) ((intptr_t) (p)))
 274 #define INT_TO_PTR(u) ((void *) ((intptr_t) (u)))
 275 #define PTR_TO_UINT(p) ((unsigned int) ((uintptr_t) (p)))
 276 #define UINT_TO_PTR(u) ((void *) ((uintptr_t) (u)))
 277
 278 #define PTR_TO_LONG(p) ((long) ((intptr_t) (p)))
 279 #define LONG_TO_PTR(u) ((void *) ((intptr_t) (u)))
 280 #define PTR_TO_ULONG(p) ((unsigned long) ((uintptr_t) (p)))
 281 #define ULONG_TO_PTR(u) ((void *) ((uintptr_t) (u)))
 282
 283 #define PTR_TO_INT32(p) ((int32_t) ((intptr_t) (p)))
 284 #define INT32_TO_PTR(u) ((void *) ((intptr_t) (u)))
 285 #define PTR_TO_UINT32(p) ((uint32_t) ((uintptr_t) (p)))
 286 #define UINT32_TO_PTR(u) ((void *) ((uintptr_t) (u)))
 287
 288 #define PTR_TO_INT64(p) ((int64_t) ((intptr_t) (p)))
 289 #define INT64_TO_PTR(u) ((void *) ((intptr_t) (u)))
 290 #define PTR_TO_UINT64(p) ((uint64_t) ((uintptr_t) (p)))
 291 #define UINT64_TO_PTR(u) ((void *) ((uintptr_t) (u)))
 292
 293 #define PTR_TO_SIZE(p) ((size_t) ((uintptr_t) (p)))
 294 #define SIZE_TO_PTR(u) ((void *) ((uintptr_t) (u)))
 295
 296 /* The following macros add 1 when converting things, since UID 0 is a
 297  * valid UID, while the pointer NULL is special */
 298 #define PTR_TO_UID(p) ((uid_t) (((uintptr_t) (p))-1))
 299 #define UID_TO_PTR(u) ((void*) (((uintptr_t) (u))+1))
 300
 301 #define PTR_TO_GID(p) ((gid_t) (((uintptr_t) (p))-1))
 302 #define GID_TO_PTR(u) ((void*) (((uintptr_t) (u))+1))
 303
 304 #define PTR_TO_PID(p) ((pid_t) ((uintptr_t) p))
 305 #define PID_TO_PTR(p) ((void*) ((uintptr_t) p))
 306
 307 #define memzero(x,l) (memset((x), 0, (l)))
 308 #define zero(x) (memzero(&(x), sizeof(x)))
 309
 310 #define CHAR_TO_STR(x) ((char[2]) { x, 0 })
 311
 312 #define char_array_0(x) x[sizeof(x)-1] = 0;
 313
 314 #define IOVEC_SET_STRING(i, s)                  \
 315         do {                                    \
 316                 struct iovec *_i = &(i);        \
 317                 char *_s = (char *)(s);         \
 318                 _i->iov_base = _s;              \
 319                 _i->iov_len = strlen(_s);       \
 320         } while(false)
 321
 322 static inline size_t IOVEC_TOTAL_SIZE(const struct iovec *i, unsigned n) {
 323         unsigned j;
 324         size_t r = 0;
 325
 326         for (j = 0; j < n; j++)
 327                 r += i[j].iov_len;
 328
 329         return r;
 330 }
 331
 332 static inline size_t IOVEC_INCREMENT(struct iovec *i, unsigned n, size_t k) {
 333         unsigned j;
 334
 335         for (j = 0; j < n; j++) {
 336                 size_t sub;
 337
 338                 if (_unlikely_(k <= 0))
 339                         break;
 340
 341                 sub = MIN(i[j].iov_len, k);
 342                 i[j].iov_len -= sub;
 343                 i[j].iov_base = (uint8_t*) i[j].iov_base + sub;
 344                 k -= sub;
 345         }
 346
 347         return k;
 348 }
 349
 350 #define VA_FORMAT_ADVANCE(format, ap)                                   \
 351 do {                                                                    \
 352         int _argtypes[128];                                             \
 353         size_t _i, _k;                                                  \
 354         _k = parse_printf_format((format), ELEMENTSOF(_argtypes), _argtypes); \
 355         assert(_k < ELEMENTSOF(_argtypes));                             \
 356         for (_i = 0; _i < _k; _i++) {                                   \
 357                 if (_argtypes[_i] & PA_FLAG_PTR)  {                     \
 358                         (void) va_arg(ap, void*);                       \
 359                         continue;                                       \
 360                 }                                                       \
 361                                                                         \
 362                 switch (_argtypes[_i]) {                                \
 363                 case PA_INT:                                            \
 364                 case PA_INT|PA_FLAG_SHORT:                              \
 365                 case PA_CHAR:                                           \
 366                         (void) va_arg(ap, int);                         \
 367                         break;                                          \
 368                 case PA_INT|PA_FLAG_LONG:                               \
 369                         (void) va_arg(ap, long int);                    \
 370                         break;                                          \
 371                 case PA_INT|PA_FLAG_LONG_LONG:                          \
 372                         (void) va_arg(ap, long long int);               \
 373                         break;                                          \
 374                 case PA_WCHAR:                                          \
 375                         (void) va_arg(ap, wchar_t);                     \
 376                         break;                                          \
 377                 case PA_WSTRING:                                        \
 378                 case PA_STRING:                                         \
 379                 case PA_POINTER:                                        \
 380                         (void) va_arg(ap, void*);                       \
 381                         break;                                          \
 382                 case PA_FLOAT:                                          \
 383                 case PA_DOUBLE:                                         \
 384                         (void) va_arg(ap, double);                      \
 385                         break;                                          \
 386                 case PA_DOUBLE|PA_FLAG_LONG_DOUBLE:                     \
 387                         (void) va_arg(ap, long double);                 \
 388                         break;                                          \
 389                 default:                                                \
 390                         assert_not_reached("Unknown format string argument."); \
 391                 }                                                       \
 392         }                                                               \
 393 } while(false)
 394
 395  /* Because statfs.t_type can be int on some architectures, we have to cast
 396   * the const magic to the type, otherwise the compiler warns about
 397   * signed/unsigned comparison, because the magic can be 32 bit unsigned.
 398  */
 399 #define F_TYPE_EQUAL(a, b) (a == (typeof(a)) b)
 400
 401 /* Returns the number of chars needed to format variables of the
 402  * specified type as a decimal string. Adds in extra space for a
 403  * negative '-' prefix (hence works correctly on signed
 404  * types). Includes space for the trailing NUL. */
 405 #define DECIMAL_STR_MAX(type)                                           \
 406         (2+(sizeof(type) <= 1 ? 3 :                                     \
 407             sizeof(type) <= 2 ? 5 :                                     \
 408             sizeof(type) <= 4 ? 10 :                                    \
 409             sizeof(type) <= 8 ? 20 : sizeof(int[-2*(sizeof(type) > 8)])))
 410
 411 #define SET_FLAG(v, flag, b) \
 412         (v) = (b) ? ((v) | (flag)) : ((v) & ~(flag))
 413
 414 #define IN_SET(x, y, ...)                                               \
 415         ({                                                              \
 416                 static const typeof(y) _array[] = { (y), __VA_ARGS__ }; \
 417                 const typeof(y) _x = (x);                               \
 418                 unsigned _i;                                            \
 419                 bool _found = false;                                    \
 420                 for (_i = 0; _i < ELEMENTSOF(_array); _i++)             \
 421                         if (_array[_i] == _x) {                         \
 422                                 _found = true;                          \
 423                                 break;                                  \
 424                         }                                               \
 425                 _found;                                                 \
 426         })
 427
 428 /* Return a nulstr for a standard cascade of configuration directories,
 429  * suitable to pass to conf_files_list_nulstr or config_parse_many. */
 430 #define CONF_DIRS_NULSTR(n) \
 431         "/etc/" n ".d\0" \
 432         "/run/" n ".d\0" \
 433         "/usr/local/lib/" n ".d\0" \
 434         "/usr/lib/" n ".d\0" \
 435         CONF_DIR_SPLIT_USR(n)
 436
 437 #ifdef HAVE_SPLIT_USR
 438 #define CONF_DIR_SPLIT_USR(n) "/lib/" n ".d\0"
 439 #else
 440 #define CONF_DIR_SPLIT_USR(n)
 441 #endif
 442
 443 /* Define C11 thread_local attribute even on older gcc compiler
 444  * version */
 445 #ifndef thread_local
 446 /*
 447  * Don't break on glibc < 2.16 that doesn't define __STDC_NO_THREADS__
 448  * see http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53769
 449  */
 450 #if __STDC_VERSION__ >= 201112L && !(defined(__STDC_NO_THREADS__) || (defined(__GNU_LIBRARY__) && __GLIBC__ == 2 && __GLIBC_MINOR__ < 16))
 451 #define thread_local _Thread_local
 452 #else
 453 #define thread_local __thread
 454 #endif
 455 #endif
 456
 457 /* Define C11 noreturn without <stdnoreturn.h> and even on older gcc
 458  * compiler versions */
 459 #ifndef noreturn
 460 #if __STDC_VERSION__ >= 201112L
 461 #define noreturn _Noreturn
 462 #else
 463 #define noreturn __attribute__((noreturn))
 464 #endif
 465 #endif
 466
 467 #define UID_INVALID ((uid_t) -1)
 468 #define GID_INVALID ((gid_t) -1)
 469 #define MODE_INVALID ((mode_t) -1)
 470
 471 static inline bool UID_IS_INVALID(uid_t uid) {
 472         /* We consider both the old 16bit -1 user and the newer 32bit
 473          * -1 user invalid, since they are or used to be incompatible
 474          * with syscalls such as setresuid() or chown(). */
 475
 476         return uid == (uid_t) ((uint32_t) -1) || uid == (uid_t) ((uint16_t) -1);
 477 }
 478
 479 static inline bool GID_IS_INVALID(gid_t gid) {
 480         return gid == (gid_t) ((uint32_t) -1) || gid == (gid_t) ((uint16_t) -1);
 481 }
 482
 483 #define DEFINE_TRIVIAL_CLEANUP_FUNC(type, func)                 \
 484         static inline void func##p(type *p) {                   \
 485                 if (*p)                                         \
 486                         func(*p);                               \
 487         }                                                       \
 488         struct __useless_struct_to_allow_trailing_semicolon__
 489
 490 #define CMSG_FOREACH(cmsg, mh)                                          \
 491         for ((cmsg) = CMSG_FIRSTHDR(mh); (cmsg); (cmsg) = CMSG_NXTHDR((mh), (cmsg)))
 492
 493 #include "log.h"