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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-10 20:49:52 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-10 20:49:52 +0000
commit55944e5e40b1be2afc4855d8d2baf4b73d1876b5 (patch)
tree33f869f55a1b149e9b7c2b7e201867ca5dd52992 /src/basic/macro.h
parentInitial commit. (diff)
downloadsystemd-55944e5e40b1be2afc4855d8d2baf4b73d1876b5.tar.xz
systemd-55944e5e40b1be2afc4855d8d2baf4b73d1876b5.zip
Adding upstream version 255.4.upstream/255.4
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/basic/macro.h')
-rw-r--r--src/basic/macro.h392
1 files changed, 392 insertions, 0 deletions
diff --git a/src/basic/macro.h b/src/basic/macro.h
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--- /dev/null
+++ b/src/basic/macro.h
@@ -0,0 +1,392 @@
+/* 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 "constants.h"
+#include "macro-fundamental.h"
+
+/* 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 use case 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
+
+#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
+
+/* 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
+
+static inline uint64_t u64_multiply_safe(uint64_t a, uint64_t b) {
+ if (_unlikely_(a != 0 && b > (UINT64_MAX / a)))
+ return 0; /* overflow */
+
+ return a * b;
+}
+
+/* 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__, __func__); \
+ } while (false)
+
+#define assert_log(expr, message) ((_likely_(expr)) \
+ ? (true) \
+ : (log_assert_failed_return(message, PROJECT_FILE, __LINE__, __func__), 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) ({ if (!(expr)) __builtin_unreachable(); })
+#else
+#define assert(expr) assert_message_se(expr, #expr)
+#endif
+
+#define assert_not_reached() \
+ log_assert_failed_unreachable(PROJECT_FILE, __LINE__, __func__)
+
+#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)
+#define endoffsetof_field(struct_type, member) (offsetof(struct_type, member) + sizeof_field(struct_type, member))
+
+/* Maximum buffer size needed for formatting an unsigned integer type as hex, including space for '0x'
+ * prefix and trailing NUL suffix. */
+#define HEXADECIMAL_STR_MAX(type) (2 + sizeof(type) * 2 + 1)
+
+/* 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 for signed types. Includes space for the trailing NUL. */
+#define DECIMAL_STR_MAX(type) \
+ ((size_t) IS_SIGNED_INTEGER_TYPE(type) + 1U + \
+ (sizeof(type) <= 1 ? 3U : \
+ sizeof(type) <= 2 ? 5U : \
+ sizeof(type) <= 4 ? 10U : \
+ sizeof(type) <= 8 ? (IS_SIGNED_INTEGER_TYPE(type) ? 19U : 20U) : sizeof(int[-2*(sizeof(type) > 8)])))
+
+/* Returns the number of chars needed to format the specified integer value. It's hence more specific than
+ * DECIMAL_STR_MAX() which answers the same question for all possible values of the specified type. Does
+ * *not* include space for a trailing NUL. (If you wonder why we special case _x_ == 0 here: it's to trick
+ * out gcc's -Wtype-limits, which would complain on comparing an unsigned type with < 0, otherwise. By
+ * special-casing == 0 here first, we can use <= 0 instead of < 0 to trick out gcc.) */
+#define DECIMAL_STR_WIDTH(x) \
+ ({ \
+ typeof(x) _x_ = (x); \
+ size_t ans; \
+ if (_x_ == 0) \
+ ans = 1; \
+ else { \
+ ans = _x_ <= 0 ? 2 : 1; \
+ while ((_x_ /= 10) != 0) \
+ ans++; \
+ } \
+ ans; \
+ })
+
+#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 _FOREACH_ARRAY(i, array, num, m, end) \
+ for (typeof(array[0]) *i = (array), *end = ({ \
+ typeof(num) m = (num); \
+ (i && m > 0) ? i + m : NULL; \
+ }); end && i < end; i++)
+
+#define FOREACH_ARRAY(i, array, num) \
+ _FOREACH_ARRAY(i, array, num, UNIQ_T(m, UNIQ), UNIQ_T(end, UNIQ))
+
+#define _DEFINE_TRIVIAL_REF_FUNC(type, name, scope) \
+ scope type *name##_ref(type *p) { \
+ if (!p) \
+ return NULL; \
+ \
+ /* For type check. */ \
+ unsigned *q = &p->n_ref; \
+ assert(*q > 0); \
+ assert_se(*q < UINT_MAX); \
+ \
+ (*q)++; \
+ 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; \
+ })
+
+#define saturate_add(x, y, limit) \
+ ({ \
+ typeof(limit) _x = (x); \
+ typeof(limit) _y = (y); \
+ _x > (limit) || _y >= (limit) - _x ? (limit) : _x + _y; \
+ })
+
+static inline size_t size_add(size_t x, size_t y) {
+ return saturate_add(x, y, SIZE_MAX);
+}
+
+typedef struct {
+ int _empty[0];
+} dummy_t;
+
+assert_cc(sizeof(dummy_t) == 0);
+
+/* A little helper for subtracting 1 off a pointer in a safe UB-free way. This is intended to be used for
+ * loops that count down from a high pointer until some base. A naive loop would implement this like this:
+ *
+ * for (p = end-1; p >= base; p--) …
+ *
+ * But this is not safe because p before the base is UB in C. With this macro the loop becomes this instead:
+ *
+ * for (p = PTR_SUB1(end, base); p; p = PTR_SUB1(p, base)) …
+ *
+ * And is free from UB! */
+#define PTR_SUB1(p, base) \
+ ({ \
+ typeof(p) _q = (p); \
+ _q && _q > (base) ? &_q[-1] : NULL; \
+ })
+
+/* Iterate through each variadic arg. All must be the same type as 'entry' or must be implicitly
+ * convertible. The iteration variable 'entry' must already be defined. */
+#define VA_ARGS_FOREACH(entry, ...) \
+ _VA_ARGS_FOREACH(entry, UNIQ_T(_entries_, UNIQ), UNIQ_T(_current_, UNIQ), UNIQ_T(_va_sentinel_, UNIQ), ##__VA_ARGS__)
+#define _VA_ARGS_FOREACH(entry, _entries_, _current_, _va_sentinel_, ...) \
+ for (typeof(entry) _va_sentinel_[1] = {}, _entries_[] = { __VA_ARGS__ __VA_OPT__(,) _va_sentinel_[0] }, *_current_ = _entries_; \
+ ((long)(_current_ - _entries_) < (long)(ELEMENTSOF(_entries_) - 1)) && ({ entry = *_current_; true; }); \
+ _current_++)
+
+#include "log.h"