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899c1c0a34eee851435349c4e4412347ca9907b5
systemd/src/basic/macro.h
Lennart Poettering 899c1c0a34 macro: also use trailing __ for alignof use in attributes 
While the underscore is optional, the docs say we should suffix and we
do that everywher else. Do so here too.
2021-10-11 14:09:33 +02:00

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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#pragma once
#include <assert.h>
#include <errno.h>
#include <inttypes.h>
#include <stdbool.h>
#include <sys/param.h>
#include <sys/sysmacros.h>
#include <sys/types.h>
#include "macro-fundamental.h"
#define _printf_(a, b) __attribute__((__format__(printf, a, b)))
#ifdef __clang__
# define _alloc_(...)
#else
# define _alloc_(...) __attribute__((__alloc_size__(__VA_ARGS__)))
#endif
#define _sentinel_ __attribute__((__sentinel__))
#define _destructor_ __attribute__((__destructor__))
#define _deprecated_ __attribute__((__deprecated__))
#define _malloc_ __attribute__((__malloc__))
#define _weak_ __attribute__((__weak__))
#define _public_ __attribute__((__visibility__("default")))
#define _hidden_ __attribute__((__visibility__("hidden")))
#define _weakref_(x) __attribute__((__weakref__(#x)))
#define _alignas_(x) __attribute__((__aligned__(__alignof__(x))))
#define _alignptr_ __attribute__((__aligned__(sizeof(void*))))
#define _warn_unused_result_ __attribute__((__warn_unused_result__))
#if !defined(HAS_FEATURE_MEMORY_SANITIZER)
# if defined(__has_feature)
# if __has_feature(memory_sanitizer)
# define HAS_FEATURE_MEMORY_SANITIZER 1
# endif
# endif
# if !defined(HAS_FEATURE_MEMORY_SANITIZER)
# define HAS_FEATURE_MEMORY_SANITIZER 0
# endif
#endif
#if !defined(HAS_FEATURE_ADDRESS_SANITIZER)
# ifdef __SANITIZE_ADDRESS__
# define HAS_FEATURE_ADDRESS_SANITIZER 1
# elif defined(__has_feature)
# if __has_feature(address_sanitizer)
# define HAS_FEATURE_ADDRESS_SANITIZER 1
# endif
# endif
# if !defined(HAS_FEATURE_ADDRESS_SANITIZER)
# define HAS_FEATURE_ADDRESS_SANITIZER 0
# endif
#endif
/* Note: on GCC "no_sanitize_address" is a function attribute only, on llvm it may also be applied to global
* variables. We define a specific macro which knows this. Note that on GCC we don't need this decorator so much, since
* our primary usecase for this attribute is registration structures placed in named ELF sections which shall not be
* padded, but GCC doesn't pad those anyway if AddressSanitizer is enabled. */
#if HAS_FEATURE_ADDRESS_SANITIZER && defined(__clang__)
#define _variable_no_sanitize_address_ __attribute__((__no_sanitize_address__))
#else
#define _variable_no_sanitize_address_
#endif
/* Apparently there's no has_feature() call defined to check for ubsan, hence let's define this
* unconditionally on llvm */
#if defined(__clang__)
#define _function_no_sanitize_float_cast_overflow_ __attribute__((no_sanitize("float-cast-overflow")))
#else
#define _function_no_sanitize_float_cast_overflow_
#endif
/* Temporarily disable some warnings */
#define DISABLE_WARNING_DEPRECATED_DECLARATIONS \
_Pragma("GCC diagnostic push"); \
_Pragma("GCC diagnostic ignored \"-Wdeprecated-declarations\"")
#define DISABLE_WARNING_FORMAT_NONLITERAL \
_Pragma("GCC diagnostic push"); \
_Pragma("GCC diagnostic ignored \"-Wformat-nonliteral\"")
#define DISABLE_WARNING_MISSING_PROTOTYPES \
_Pragma("GCC diagnostic push"); \
_Pragma("GCC diagnostic ignored \"-Wmissing-prototypes\"")
#define DISABLE_WARNING_NONNULL \
_Pragma("GCC diagnostic push"); \
_Pragma("GCC diagnostic ignored \"-Wnonnull\"")
#define DISABLE_WARNING_SHADOW \
_Pragma("GCC diagnostic push"); \
_Pragma("GCC diagnostic ignored \"-Wshadow\"")
#define DISABLE_WARNING_INCOMPATIBLE_POINTER_TYPES \
_Pragma("GCC diagnostic push"); \
_Pragma("GCC diagnostic ignored \"-Wincompatible-pointer-types\"")
#if HAVE_WSTRINGOP_TRUNCATION
# define DISABLE_WARNING_STRINGOP_TRUNCATION \
_Pragma("GCC diagnostic push"); \
_Pragma("GCC diagnostic ignored \"-Wstringop-truncation\"")
#else
# define DISABLE_WARNING_STRINGOP_TRUNCATION \
_Pragma("GCC diagnostic push")
#endif
#define DISABLE_WARNING_FLOAT_EQUAL \
_Pragma("GCC diagnostic push"); \
_Pragma("GCC diagnostic ignored \"-Wfloat-equal\"")
#define DISABLE_WARNING_TYPE_LIMITS \
_Pragma("GCC diagnostic push"); \
_Pragma("GCC diagnostic ignored \"-Wtype-limits\"")
#define REENABLE_WARNING \
_Pragma("GCC diagnostic pop")
/* automake test harness */
#define EXIT_TEST_SKIP 77
/* builtins */
#if __SIZEOF_INT__ == 4
#define BUILTIN_FFS_U32(x) __builtin_ffs(x);
#elif __SIZEOF_LONG__ == 4
#define BUILTIN_FFS_U32(x) __builtin_ffsl(x);
#else
#error "neither int nor long are four bytes long?!?"
#endif
/* Rounds up */
#define ALIGN4(l) (((l) + 3) & ~3)
#define ALIGN8(l) (((l) + 7) & ~7)
#if __SIZEOF_POINTER__ == 8
#define ALIGN(l) ALIGN8(l)
#elif __SIZEOF_POINTER__ == 4
#define ALIGN(l) ALIGN4(l)
#else
#error "Wut? Pointers are neither 4 nor 8 bytes long?"
#endif
#define ALIGN_PTR(p) ((void*) ALIGN((unsigned long) (p)))
#define ALIGN4_PTR(p) ((void*) ALIGN4((unsigned long) (p)))
#define ALIGN8_PTR(p) ((void*) ALIGN8((unsigned long) (p)))
static inline size_t ALIGN_TO(size_t l, size_t ali) {
/* Check that alignment is exponent of 2 */
#if SIZE_MAX == UINT_MAX
assert(__builtin_popcount(ali) == 1);
#elif SIZE_MAX == ULONG_MAX
assert(__builtin_popcountl(ali) == 1);
#elif SIZE_MAX == ULLONG_MAX
assert(__builtin_popcountll(ali) == 1);
#else
#error "Unexpected size_t"
#endif
if (l > SIZE_MAX - (ali - 1))
return SIZE_MAX; /* indicate overflow */
return ((l + ali - 1) & ~(ali - 1));
}
#define ALIGN_TO_PTR(p, ali) ((void*) ALIGN_TO((unsigned long) (p), (ali)))
/* align to next higher power-of-2 (except for: 0 => 0, overflow => 0) */
static inline unsigned long ALIGN_POWER2(unsigned long u) {
/* Avoid subtraction overflow */
if (u == 0)
return 0;
/* clz(0) is undefined */
if (u == 1)
return 1;
/* left-shift overflow is undefined */
if (__builtin_clzl(u - 1UL) < 1)
return 0;
return 1UL << (sizeof(u) * 8 - __builtin_clzl(u - 1UL));
}
static inline size_t GREEDY_ALLOC_ROUND_UP(size_t l) {
size_t m;
/* Round up allocation sizes a bit to some reasonable, likely larger value. This is supposed to be
* used for cases which are likely called in an allocation loop of some form, i.e. that repetitively
* grow stuff, for example strv_extend() and suchlike.
*
* Note the difference to GREEDY_REALLOC() here, as this helper operates on a single size value only,
* and rounds up to next multiple of 2, needing no further counter.
*
* Note the benefits of direct ALIGN_POWER2() usage: type-safety for size_t, sane handling for very
* small (i.e. <= 2) and safe handling for very large (i.e. > SSIZE_MAX) values. */
if (l <= 2)
return 2; /* Never allocate less than 2 of something. */
m = ALIGN_POWER2(l);
if (m == 0) /* overflow? */
return l;
return m;
}
/*
* container_of - cast a member of a structure out to the containing structure
* @ptr: the pointer to the member.
* @type: the type of the container struct this is embedded in.
* @member: the name of the member within the struct.
*/
#define container_of(ptr, type, member) __container_of(UNIQ, (ptr), type, member)
#define __container_of(uniq, ptr, type, member) \
({ \
const typeof( ((type*)0)->member ) *UNIQ_T(A, uniq) = (ptr); \
(type*)( (char *)UNIQ_T(A, uniq) - offsetof(type, member) ); \
})
#ifdef __COVERITY__
/* Use special definitions of assertion macros in order to prevent
* false positives of ASSERT_SIDE_EFFECT on Coverity static analyzer
* for uses of assert_se() and assert_return().
*
* These definitions make expression go through a (trivial) function
* call to ensure they are not discarded. Also use ! or !! to ensure
* the boolean expressions are seen as such.
*
* This technique has been described and recommended in:
* https://community.synopsys.com/s/question/0D534000046Yuzb/suppressing-assertsideeffect-for-functions-that-allow-for-sideeffects
*/
extern void __coverity_panic__(void);
static inline void __coverity_check__(int condition) {
if (!condition)
__coverity_panic__();
}
static inline int __coverity_check_and_return__(int condition) {
return condition;
}
#define assert_message_se(expr, message) __coverity_check__(!!(expr))
#define assert_log(expr, message) __coverity_check_and_return__(!!(expr))
#else /* ! __COVERITY__ */
#define assert_message_se(expr, message) \
do { \
if (_unlikely_(!(expr))) \
log_assert_failed(message, PROJECT_FILE, __LINE__, __PRETTY_FUNCTION__); \
} while (false)
#define assert_log(expr, message) ((_likely_(expr)) \
? (true) \
: (log_assert_failed_return(message, PROJECT_FILE, __LINE__, __PRETTY_FUNCTION__), false))
#endif /* __COVERITY__ */
#define assert_se(expr) assert_message_se(expr, #expr)
/* We override the glibc assert() here. */
#undef assert
#ifdef NDEBUG
#define assert(expr) do {} while (false)
#else
#define assert(expr) assert_message_se(expr, #expr)
#endif
#define assert_not_reached() \
log_assert_failed_unreachable(PROJECT_FILE, __LINE__, __PRETTY_FUNCTION__)
#define assert_return(expr, r) \
do { \
if (!assert_log(expr, #expr)) \
return (r); \
} while (false)
#define assert_return_errno(expr, r, err) \
do { \
if (!assert_log(expr, #expr)) { \
errno = err; \
return (r); \
} \
} while (false)
#define return_with_errno(r, err) \
do { \
errno = abs(err); \
return r; \
} while (false)
#define PTR_TO_INT(p) ((int) ((intptr_t) (p)))
#define INT_TO_PTR(u) ((void *) ((intptr_t) (u)))
#define PTR_TO_UINT(p) ((unsigned) ((uintptr_t) (p)))
#define UINT_TO_PTR(u) ((void *) ((uintptr_t) (u)))
#define PTR_TO_LONG(p) ((long) ((intptr_t) (p)))
#define LONG_TO_PTR(u) ((void *) ((intptr_t) (u)))
#define PTR_TO_ULONG(p) ((unsigned long) ((uintptr_t) (p)))
#define ULONG_TO_PTR(u) ((void *) ((uintptr_t) (u)))
#define PTR_TO_UINT8(p) ((uint8_t) ((uintptr_t) (p)))
#define UINT8_TO_PTR(u) ((void *) ((uintptr_t) (u)))
#define PTR_TO_INT32(p) ((int32_t) ((intptr_t) (p)))
#define INT32_TO_PTR(u) ((void *) ((intptr_t) (u)))
#define PTR_TO_UINT32(p) ((uint32_t) ((uintptr_t) (p)))
#define UINT32_TO_PTR(u) ((void *) ((uintptr_t) (u)))
#define PTR_TO_INT64(p) ((int64_t) ((intptr_t) (p)))
#define INT64_TO_PTR(u) ((void *) ((intptr_t) (u)))
#define PTR_TO_UINT64(p) ((uint64_t) ((uintptr_t) (p)))
#define UINT64_TO_PTR(u) ((void *) ((uintptr_t) (u)))
#define PTR_TO_SIZE(p) ((size_t) ((uintptr_t) (p)))
#define SIZE_TO_PTR(u) ((void *) ((uintptr_t) (u)))
#define CHAR_TO_STR(x) ((char[2]) { x, 0 })
#define char_array_0(x) x[sizeof(x)-1] = 0;
#define sizeof_field(struct_type, member) sizeof(((struct_type *) 0)->member)
/* Returns the number of chars needed to format variables of the
* specified type as a decimal string. Adds in extra space for a
* negative '-' prefix (hence works correctly on signed
* types). Includes space for the trailing NUL. */
#define DECIMAL_STR_MAX(type) \
(2U+(sizeof(type) <= 1 ? 3U : \
sizeof(type) <= 2 ? 5U : \
sizeof(type) <= 4 ? 10U : \
sizeof(type) <= 8 ? 20U : sizeof(int[-2*(sizeof(type) > 8)])))
#define DECIMAL_STR_WIDTH(x) \
({ \
typeof(x) _x_ = (x); \
size_t ans = 1; \
while ((_x_ /= 10) != 0) \
ans++; \
ans; \
})
#define UPDATE_FLAG(orig, flag, b) \
((b) ? ((orig) | (flag)) : ((orig) & ~(flag)))
#define SET_FLAG(v, flag, b) \
(v) = UPDATE_FLAG(v, flag, b)
#define FLAGS_SET(v, flags) \
((~(v) & (flags)) == 0)
#define SWAP_TWO(x, y) do { \
typeof(x) _t = (x); \
(x) = (y); \
(y) = (_t); \
} while (false)
#define STRV_MAKE(...) ((char**) ((const char*[]) { __VA_ARGS__, NULL }))
#define STRV_MAKE_EMPTY ((char*[1]) { NULL })
#define STRV_MAKE_CONST(...) ((const char* const*) ((const char*[]) { __VA_ARGS__, NULL }))
/* Pointers range from NULL to POINTER_MAX */
#define POINTER_MAX ((void*) UINTPTR_MAX)
/* Iterates through a specified list of pointers. Accepts NULL pointers, but uses POINTER_MAX as internal marker for EOL. */
#define FOREACH_POINTER(p, x, ...) \
for (typeof(p) *_l = (typeof(p)[]) { ({ p = x; }), ##__VA_ARGS__, POINTER_MAX }; \
p != (typeof(p)) POINTER_MAX; \
p = *(++_l))
/* Define C11 thread_local attribute even on older gcc compiler
* version */
#ifndef thread_local
/*
* Don't break on glibc < 2.16 that doesn't define __STDC_NO_THREADS__
* see http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53769
*/
#if __STDC_VERSION__ >= 201112L && !(defined(__STDC_NO_THREADS__) || (defined(__GNU_LIBRARY__) && __GLIBC__ == 2 && __GLIBC_MINOR__ < 16))
#define thread_local _Thread_local
#else
#define thread_local __thread
#endif
#endif
#define DEFINE_TRIVIAL_DESTRUCTOR(name, type, func) \
static inline void name(type *p) { \
func(p); \
}
/* When func() returns the void value (NULL, -1, …) of the appropriate type */
#define DEFINE_TRIVIAL_CLEANUP_FUNC(type, func) \
static inline void func##p(type *p) { \
if (*p) \
*p = func(*p); \
}
/* When func() doesn't return the appropriate type, set variable to empty afterwards */
#define DEFINE_TRIVIAL_CLEANUP_FUNC_FULL(type, func, empty) \
static inline void func##p(type *p) { \
if (*p != (empty)) { \
func(*p); \
*p = (empty); \
} \
}
#define _DEFINE_TRIVIAL_REF_FUNC(type, name, scope) \
scope type *name##_ref(type *p) { \
if (!p) \
return NULL; \
\
assert(p->n_ref > 0); \
p->n_ref++; \
return p; \
}
#define _DEFINE_TRIVIAL_UNREF_FUNC(type, name, free_func, scope) \
scope type *name##_unref(type *p) { \
if (!p) \
return NULL; \
\
assert(p->n_ref > 0); \
p->n_ref--; \
if (p->n_ref > 0) \
return NULL; \
\
return free_func(p); \
}
#define DEFINE_TRIVIAL_REF_FUNC(type, name) \
_DEFINE_TRIVIAL_REF_FUNC(type, name,)
#define DEFINE_PRIVATE_TRIVIAL_REF_FUNC(type, name) \
_DEFINE_TRIVIAL_REF_FUNC(type, name, static)
#define DEFINE_PUBLIC_TRIVIAL_REF_FUNC(type, name) \
_DEFINE_TRIVIAL_REF_FUNC(type, name, _public_)
#define DEFINE_TRIVIAL_UNREF_FUNC(type, name, free_func) \
_DEFINE_TRIVIAL_UNREF_FUNC(type, name, free_func,)
#define DEFINE_PRIVATE_TRIVIAL_UNREF_FUNC(type, name, free_func) \
_DEFINE_TRIVIAL_UNREF_FUNC(type, name, free_func, static)
#define DEFINE_PUBLIC_TRIVIAL_UNREF_FUNC(type, name, free_func) \
_DEFINE_TRIVIAL_UNREF_FUNC(type, name, free_func, _public_)
#define DEFINE_TRIVIAL_REF_UNREF_FUNC(type, name, free_func) \
DEFINE_TRIVIAL_REF_FUNC(type, name); \
DEFINE_TRIVIAL_UNREF_FUNC(type, name, free_func);
#define DEFINE_PRIVATE_TRIVIAL_REF_UNREF_FUNC(type, name, free_func) \
DEFINE_PRIVATE_TRIVIAL_REF_FUNC(type, name); \
DEFINE_PRIVATE_TRIVIAL_UNREF_FUNC(type, name, free_func);
#define DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(type, name, free_func) \
DEFINE_PUBLIC_TRIVIAL_REF_FUNC(type, name); \
DEFINE_PUBLIC_TRIVIAL_UNREF_FUNC(type, name, free_func);
/* A macro to force copying of a variable from memory. This is useful whenever we want to read something from
* memory and want to make sure the compiler won't optimize away the destination variable for us. It's not
* supposed to be a full CPU memory barrier, i.e. CPU is still allowed to reorder the reads, but it is not
* allowed to remove our local copies of the variables. We want this to work for unaligned memory, hence
* memcpy() is great for our purposes. */
#define READ_NOW(x) \
({ \
typeof(x) _copy; \
memcpy(&_copy, &(x), sizeof(_copy)); \
asm volatile ("" : : : "memory"); \
_copy; \
})
static inline size_t size_add(size_t x, size_t y) {
return y >= SIZE_MAX - x ? SIZE_MAX : x + y;
}
typedef struct {
int _empty[0];
} dummy_t;
assert_cc(sizeof(dummy_t) == 0);
#include "log.h"
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