Systemd/src/shared/macro.h

/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/

#pragma once

/***
  This file is part of systemd.

  Copyright 2010 Lennart Poettering

  systemd is free software; you can redistribute it and/or modify it
  under the terms of the GNU Lesser General Public License as published by
  the Free Software Foundation; either version 2.1 of the License, or
  (at your option) any later version.

  systemd is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public License
  along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/

#include <assert.h>
#include <sys/param.h>
#include <sys/types.h>
#include <sys/uio.h>
#include <inttypes.h>

#define _printf_(a,b) __attribute__ ((format (printf, a, b)))
#define _alloc_(...) __attribute__ ((alloc_size(__VA_ARGS__)))
#define _sentinel_ __attribute__ ((sentinel))
#define _unused_ __attribute__ ((unused))
#define _destructor_ __attribute__ ((destructor))
#define _pure_ __attribute__ ((pure))
#define _const_ __attribute__ ((const))
#define _deprecated_ __attribute__ ((deprecated))
#define _packed_ __attribute__ ((packed))
#define _malloc_ __attribute__ ((malloc))
#define _weak_ __attribute__ ((weak))
#define _likely_(x) (__builtin_expect(!!(x),1))
#define _unlikely_(x) (__builtin_expect(!!(x),0))
#define _public_ __attribute__ ((visibility("default")))
#define _hidden_ __attribute__ ((visibility("hidden")))
#define _weakref_(x) __attribute__((weakref(#x)))
#define _alignas_(x) __attribute__((aligned(__alignof(x))))
#define _cleanup_(x) __attribute__((cleanup(x)))

/* Temporarily disable some warnings */
#define DISABLE_WARNING_DECLARATION_AFTER_STATEMENT                     \
        _Pragma("GCC diagnostic push");                                 \
        _Pragma("GCC diagnostic ignored \"-Wdeclaration-after-statement\"")

#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 REENABLE_WARNING                                                \
        _Pragma("GCC diagnostic pop")

/* automake test harness */
#define EXIT_TEST_SKIP 77

#define XSTRINGIFY(x) #x
#define STRINGIFY(x) XSTRINGIFY(x)

#define XCONCATENATE(x, y) x ## y
#define CONCATENATE(x, y) XCONCATENATE(x, y)

#define UNIQ_T(x, uniq) CONCATENATE(__unique_prefix_, CONCATENATE(x, uniq))
#define UNIQ __COUNTER__

/* 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) {
        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) {
        /* 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));
}

#define ELEMENTSOF(x) (sizeof(x)/sizeof((x)[0]))

/*
 * 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)                         \
        __extension__ ({                                                \
                const typeof( ((type*)0)->member ) *UNIQ_T(A, uniq) = (ptr); \
                (type*)( (char *)UNIQ_T(A, uniq) - offsetof(type,member) ); \
        })

#undef MAX
#define MAX(a, b) __MAX(UNIQ, (a), UNIQ, (b))
#define __MAX(aq, a, bq, b)                             \
        __extension__ ({                                \
                const typeof(a) UNIQ_T(A, aq) = (a);    \
                const typeof(b) UNIQ_T(B, bq) = (b);    \
                UNIQ_T(A,aq) > UNIQ_T(B,bq) ? UNIQ_T(A,aq) : UNIQ_T(B,bq); \
        })

/* evaluates to (void) if _A or _B are not constant or of different types */
#define CONST_MAX(_A, _B) \
        __extension__ (__builtin_choose_expr(                           \
                __builtin_constant_p(_A) &&                             \
                __builtin_constant_p(_B) &&                             \
                __builtin_types_compatible_p(typeof(_A), typeof(_B)),   \
                ((_A) > (_B)) ? (_A) : (_B),                            \
                (void)0))

/* takes two types and returns the size of the larger one */
#define MAXSIZE(A, B) (sizeof(union _packed_ { typeof(A) a; typeof(B) b; }))

#define MAX3(x,y,z)                                     \
        __extension__ ({                                \
                        const typeof(x) _c = MAX(x,y);  \
                        MAX(_c, z);                     \
                })

#undef MIN
#define MIN(a, b) __MIN(UNIQ, (a), UNIQ, (b))
#define __MIN(aq, a, bq, b)                             \
        __extension__ ({                                \
                const typeof(a) UNIQ_T(A, aq) = (a);    \
                const typeof(b) UNIQ_T(B, bq) = (b);    \
                UNIQ_T(A,aq) < UNIQ_T(B,bq) ? UNIQ_T(A,aq) : UNIQ_T(B,bq); \
        })

#define MIN3(x,y,z)                                     \
        __extension__ ({                                \
                        const typeof(x) _c = MIN(x,y);  \
                        MIN(_c, z);                     \
                })

#define LESS_BY(a, b) __LESS_BY(UNIQ, (a), UNIQ, (b))
#define __LESS_BY(aq, a, bq, b)                         \
        __extension__ ({                                \
                const typeof(a) UNIQ_T(A, aq) = (a);    \
                const typeof(b) UNIQ_T(B, bq) = (b);    \
                UNIQ_T(A,aq) > UNIQ_T(B,bq) ? UNIQ_T(A,aq) - UNIQ_T(B,bq) : 0; \
        })

#undef CLAMP
#define CLAMP(x, low, high) __CLAMP(UNIQ, (x), UNIQ, (low), UNIQ, (high))
#define __CLAMP(xq, x, lowq, low, highq, high)                          \
        __extension__ ({                                                \
                const typeof(x) UNIQ_T(X,xq) = (x);                     \
                const typeof(low) UNIQ_T(LOW,lowq) = (low);             \
                const typeof(high) UNIQ_T(HIGH,highq) = (high);         \
                        UNIQ_T(X,xq) > UNIQ_T(HIGH,highq) ?             \
                                UNIQ_T(HIGH,highq) :                    \
                                UNIQ_T(X,xq) < UNIQ_T(LOW,lowq) ?       \
                                        UNIQ_T(LOW,lowq) :              \
                                        UNIQ_T(X,xq);                   \
        })

/* [(x + y - 1) / y] suffers from an integer overflow, even though the
 * computation should be possible in the given type. Therefore, we use
 * [x / y + !!(x % y)]. Note that on "Real CPUs" a division returns both the
 * quotient and the remainder, so both should be equally fast. */
#define DIV_ROUND_UP(_x, _y)                                            \
        __extension__ ({                                                \
                const typeof(_x) __x = (_x);                            \
                const typeof(_y) __y = (_y);                            \
                (__x / __y + !!(__x % __y));                            \
        })

#define assert_se(expr)                                                 \
        do {                                                            \
                if (_unlikely_(!(expr)))                                \
                        log_assert_failed(#expr, __FILE__, __LINE__, __PRETTY_FUNCTION__); \
        } while (false)                                                 \

/* We override the glibc assert() here. */
#undef assert
#ifdef NDEBUG
#define assert(expr) do {} while(false)
#else
#define assert(expr) assert_se(expr)
#endif

#define assert_not_reached(t)                                           \
        do {                                                            \
                log_assert_failed_unreachable(t, __FILE__, __LINE__, __PRETTY_FUNCTION__); \
        } while (false)

#if defined(static_assert)
/* static_assert() is sometimes defined in a way that trips up
 * -Wdeclaration-after-statement, hence let's temporarily turn off
 * this warning around it. */
#define assert_cc(expr)                                                 \
        DISABLE_WARNING_DECLARATION_AFTER_STATEMENT;                    \
        static_assert(expr, #expr);                                     \
        REENABLE_WARNING
#else
#define assert_cc(expr)                                                 \
        DISABLE_WARNING_DECLARATION_AFTER_STATEMENT;                    \
        struct CONCATENATE(_assert_struct_, __COUNTER__) {              \
                char x[(expr) ? 0 : -1];                                \
        };                                                              \
        REENABLE_WARNING
#endif

#define assert_return(expr, r)                                          \
        do {                                                            \
                if (_unlikely_(!(expr))) {                              \
                        log_assert_failed_return(#expr, __FILE__, __LINE__, __PRETTY_FUNCTION__); \
                        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 int) ((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_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)))

/* The following macros add 1 when converting things, since UID 0 is a
 * valid UID, while the pointer NULL is special */
#define PTR_TO_UID(p) ((uid_t) (((uintptr_t) (p))-1))
#define UID_TO_PTR(u) ((void*) (((uintptr_t) (u))+1))

#define PTR_TO_GID(p) ((gid_t) (((uintptr_t) (p))-1))
#define GID_TO_PTR(u) ((void*) (((uintptr_t) (u))+1))

#define memzero(x,l) (memset((x), 0, (l)))
#define zero(x) (memzero(&(x), sizeof(x)))

#define CHAR_TO_STR(x) ((char[2]) { x, 0 })

#define char_array_0(x) x[sizeof(x)-1] = 0;

#define IOVEC_SET_STRING(i, s)                  \
        do {                                    \
                struct iovec *_i = &(i);        \
                char *_s = (char *)(s);         \
                _i->iov_base = _s;              \
                _i->iov_len = strlen(_s);       \
        } while(false)

static inline size_t IOVEC_TOTAL_SIZE(const struct iovec *i, unsigned n) {
        unsigned j;
        size_t r = 0;

        for (j = 0; j < n; j++)
                r += i[j].iov_len;

        return r;
}

static inline size_t IOVEC_INCREMENT(struct iovec *i, unsigned n, size_t k) {
        unsigned j;

        for (j = 0; j < n; j++) {
                size_t sub;

                if (_unlikely_(k <= 0))
                        break;

                sub = MIN(i[j].iov_len, k);
                i[j].iov_len -= sub;
                i[j].iov_base = (uint8_t*) i[j].iov_base + sub;
                k -= sub;
        }

        return k;
}

#define VA_FORMAT_ADVANCE(format, ap)                                   \
do {                                                                    \
        int _argtypes[128];                                             \
        size_t _i, _k;                                                  \
        _k = parse_printf_format((format), ELEMENTSOF(_argtypes), _argtypes); \
        assert(_k < ELEMENTSOF(_argtypes));                             \
        for (_i = 0; _i < _k; _i++) {                                   \
                if (_argtypes[_i] & PA_FLAG_PTR)  {                     \
                        (void) va_arg(ap, void*);                       \
                        continue;                                       \
                }                                                       \
                                                                        \
                switch (_argtypes[_i]) {                                \
                case PA_INT:                                            \
                case PA_INT|PA_FLAG_SHORT:                              \
                case PA_CHAR:                                           \
                        (void) va_arg(ap, int);                         \
                        break;                                          \
                case PA_INT|PA_FLAG_LONG:                               \
                        (void) va_arg(ap, long int);                    \
                        break;                                          \
                case PA_INT|PA_FLAG_LONG_LONG:                          \
                        (void) va_arg(ap, long long int);               \
                        break;                                          \
                case PA_WCHAR:                                          \
                        (void) va_arg(ap, wchar_t);                     \
                        break;                                          \
                case PA_WSTRING:                                        \
                case PA_STRING:                                         \
                case PA_POINTER:                                        \
                        (void) va_arg(ap, void*);                       \
                        break;                                          \
                case PA_FLOAT:                                          \
                case PA_DOUBLE:                                         \
                        (void) va_arg(ap, double);                      \
                        break;                                          \
                case PA_DOUBLE|PA_FLAG_LONG_DOUBLE:                     \
                        (void) va_arg(ap, long double);                 \
                        break;                                          \
                default:                                                \
                        assert_not_reached("Unknown format string argument."); \
                }                                                       \
        }                                                               \
} while(false)

 /* Because statfs.t_type can be int on some architectures, we have to cast
  * the const magic to the type, otherwise the compiler warns about
  * signed/unsigned comparison, because the magic can be 32 bit unsigned.
 */
#define F_TYPE_EQUAL(a, b) (a == (typeof(a)) b)

/* 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. */
#define DECIMAL_STR_MAX(type)                                           \
        (2+(sizeof(type) <= 1 ? 3 :                                     \
            sizeof(type) <= 2 ? 5 :                                     \
            sizeof(type) <= 4 ? 10 :                                    \
            sizeof(type) <= 8 ? 20 : sizeof(int[-2*(sizeof(type) > 8)])))

#define SET_FLAG(v, flag, b) \
        (v) = (b) ? ((v) | (flag)) : ((v) & ~(flag))

#define IN_SET(x, y, ...)                                               \
        ({                                                              \
                const typeof(y) _y = (y);                               \
                const typeof(_y) _x = (x);                              \
                unsigned _i;                                            \
                bool _found = false;                                    \
                for (_i = 0; _i < 1 + sizeof((const typeof(_x)[]) { __VA_ARGS__ })/sizeof(const typeof(_x)); _i++) \
                        if (((const typeof(_x)[]) { _y, __VA_ARGS__ })[_i] == _x) { \
                                _found = true;                          \
                                break;                                  \
                        }                                               \
                _found;                                                 \
        })

/* Return a nulstr for a standard cascade of configuration directories,
 * suitable to pass to conf_files_list_nulstr or config_parse_many. */
#define CONF_DIRS_NULSTR(n) \
        "/etc/" n ".d\0" \
        "/run/" n ".d\0" \
        "/usr/local/lib/" n ".d\0" \
        "/usr/lib/" n ".d\0" \
        CONF_DIR_SPLIT_USR(n)

#ifdef HAVE_SPLIT_USR
#define CONF_DIR_SPLIT_USR(n) "/lib/" n ".d\0"
#else
#define CONF_DIR_SPLIT_USR(n)
#endif

/* 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 C11 noreturn without <stdnoreturn.h> and even on older gcc
 * compiler versions */
#ifndef noreturn
#if __STDC_VERSION__ >= 201112L
#define noreturn _Noreturn
#else
#define noreturn __attribute__((noreturn))
#endif
#endif

#define UID_INVALID ((uid_t) -1)
#define GID_INVALID ((gid_t) -1)
#define MODE_INVALID ((mode_t) -1)

#define DEFINE_TRIVIAL_CLEANUP_FUNC(type, func)                 \
        static inline void func##p(type *p) {                   \
                if (*p)                                         \
                        func(*p);                               \
        }                                                       \
        struct __useless_struct_to_allow_trailing_semicolon__

#include "log.h"