[lttng-tools.git] / src / common / macros.h

/*
 * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
 * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * SPDX-License-Identifier: GPL-2.0-only
 *
 */

#ifndef _MACROS_H
#define _MACROS_H

#include <stdlib.h>
#include <stddef.h>
#include <string.h>
#include <common/compat/string.h>

/*
 * Takes a pointer x and transform it so we can use it to access members
 * without a function call. Here an example:
 *
 *    #define GET_SIZE(x) LTTNG_REF(x)->size
 *
 *    struct { int size; } s;
 *
 *    printf("size : %d\n", GET_SIZE(&s));
 *
 * For this example we can't use something like this for compatibility purpose
 * since this will fail:
 *
 *    #define GET_SIZE(x) x->size;
 *
 * This is mostly use for the compatibility layer of lttng-tools. See
 * poll/epoll for a good example. Since x can be on the stack or allocated
 * memory using malloc(), we must use generic accessors for compat in order to
 * *not* use a function to access members and not the variable name.
 */
#define LTTNG_REF(x) ((typeof(*x) *)(x))

/*
 * Memory allocation zeroed
 */
static inline
void *zmalloc(size_t len)
{
	return calloc(1, len);
}

#ifndef ARRAY_SIZE
#define ARRAY_SIZE(array)   (sizeof(array) / (sizeof((array)[0])))
#endif

#ifndef container_of
#define container_of(ptr, type, member)					\
	({								\
		const typeof(((type *)NULL)->member) * __ptr = (ptr);	\
		(type *)((char *)__ptr - offsetof(type, member));	\
	})
#endif

#ifndef max
#define max(a, b) ((a) > (b) ? (a) : (b))
#endif

#ifndef max_t
#define max_t(type, a, b)	max((type) a, (type) b)
#endif

#ifndef min
#define min(a, b) ((a) < (b) ? (a) : (b))
#endif

#ifndef min_t
#define min_t(type, a, b)	min((type) a, (type) b)
#endif

#ifndef LTTNG_PACKED
#define LTTNG_PACKED __attribute__((__packed__))
#endif

#ifndef LTTNG_NO_SANITIZE_ADDRESS
#if defined(__clang__) || defined (__GNUC__)
#define LTTNG_NO_SANITIZE_ADDRESS __attribute__((no_sanitize_address))
#else
#define LTTNG_NO_SANITIZE_ADDRESS
#endif
#endif

#define is_signed(type) (((type) -1) < (type) 1)

/*
 * Align value to the next multiple of align. Returns val if it already is a
 * multiple of align. Align must be a power of two.
 */
#define ALIGN_TO(value, align) ((value + (align - 1)) & ~(align - 1))

/*
 * LTTNG_HIDDEN: set the hidden attribute for internal functions
 * On Windows, symbols are local unless explicitly exported,
 * see https://gcc.gnu.org/wiki/Visibility
 */
#if defined(_WIN32) || defined(__CYGWIN__)
#define LTTNG_HIDDEN
#else
#define LTTNG_HIDDEN __attribute__((visibility("hidden")))
#endif

#define member_sizeof(type, field)	sizeof(((type *) 0)->field)

#define ASSERT_LOCKED(lock) assert(pthread_mutex_trylock(&lock))

/*
 * Get an aligned pointer to a value. This is meant
 * as a helper to pass an aligned pointer to a member in a packed structure
 * to a function.
 */
#define ALIGNED_CONST_PTR(value) (((const typeof(value) []) { value }))

/*
 * lttng_strncpy returns 0 on success, or nonzero on failure.
 * It checks that the @src string fits into @dst_len before performing
 * the copy. On failure, no copy has been performed.
 *
 * dst_len includes the string's trailing NULL.
 */
static inline
int lttng_strncpy(char *dst, const char *src, size_t dst_len)
{
	if (lttng_strnlen(src, dst_len) >= dst_len) {
		/* Fail since copying would result in truncation. */
		return -1;
	}
	strcpy(dst, src);
	return 0;
}

#endif /* _MACROS_H */
Commit	Line	Data
	1	/*
	2	* Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
	3	* Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	4	*
	5	* SPDX-License-Identifier: GPL-2.0-only
	6	*
	7	*/
	8
	9	#ifndef _MACROS_H
	10	#define _MACROS_H
	11
	12	#include <stdlib.h>
	13	#include <stddef.h>
	14	#include <string.h>
	15	#include <common/compat/string.h>
	16
	17	/*
	18	* Takes a pointer x and transform it so we can use it to access members
	19	* without a function call. Here an example:
	20	*
	21	* #define GET_SIZE(x) LTTNG_REF(x)->size
	22	*
	23	* struct { int size; } s;
	24	*
	25	* printf("size : %d\n", GET_SIZE(&s));
	26	*
	27	* For this example we can't use something like this for compatibility purpose
	28	* since this will fail:
	29	*
	30	* #define GET_SIZE(x) x->size;
	31	*
	32	* This is mostly use for the compatibility layer of lttng-tools. See
	33	* poll/epoll for a good example. Since x can be on the stack or allocated
	34	* memory using malloc(), we must use generic accessors for compat in order to
	35	* not use a function to access members and not the variable name.
	36	*/
	37	#define LTTNG_REF(x) ((typeof(x) )(x))
	38
	39	/*
	40	* Memory allocation zeroed
	41	*/
	42	static inline
	43	void *zmalloc(size_t len)
	44	{
	45	return calloc(1, len);
	46	}
	47
	48	#ifndef ARRAY_SIZE
	49	#define ARRAY_SIZE(array) (sizeof(array) / (sizeof((array)[0])))
	50	#endif
	51
	52	#ifndef container_of
	53	#define container_of(ptr, type, member) \
	54	({ \
	55	const typeof(((type )NULL)->member) __ptr = (ptr); \
	56	(type )((char )__ptr - offsetof(type, member)); \
	57	})
	58	#endif
	59
	60	#ifndef max
	61	#define max(a, b) ((a) > (b) ? (a) : (b))
	62	#endif
	63
	64	#ifndef max_t
	65	#define max_t(type, a, b) max((type) a, (type) b)
	66	#endif
	67
	68	#ifndef min
	69	#define min(a, b) ((a) < (b) ? (a) : (b))
	70	#endif
	71
	72	#ifndef min_t
	73	#define min_t(type, a, b) min((type) a, (type) b)
	74	#endif
	75
	76	#ifndef LTTNG_PACKED
	77	#define LTTNG_PACKED __attribute__((__packed__))
	78	#endif
	79
	80	#ifndef LTTNG_NO_SANITIZE_ADDRESS
	81	#if defined(__clang__) \|\| defined (__GNUC__)
	82	#define LTTNG_NO_SANITIZE_ADDRESS __attribute__((no_sanitize_address))
	83	#else
	84	#define LTTNG_NO_SANITIZE_ADDRESS
	85	#endif
	86	#endif
	87
	88	#define is_signed(type) (((type) -1) < (type) 1)
	89
	90	/*
	91	* Align value to the next multiple of align. Returns val if it already is a
	92	* multiple of align. Align must be a power of two.
	93	*/
	94	#define ALIGN_TO(value, align) ((value + (align - 1)) & ~(align - 1))
	95
	96	/*
	97	* LTTNG_HIDDEN: set the hidden attribute for internal functions
	98	* On Windows, symbols are local unless explicitly exported,
	99	* see https://gcc.gnu.org/wiki/Visibility
	100	*/
	101	#if defined(_WIN32) \|\| defined(__CYGWIN__)
	102	#define LTTNG_HIDDEN
	103	#else
	104	#define LTTNG_HIDDEN __attribute__((visibility("hidden")))
	105	#endif
	106
	107	#define member_sizeof(type, field) sizeof(((type *) 0)->field)
	108
	109	#define ASSERT_LOCKED(lock) assert(pthread_mutex_trylock(&lock))
	110
	111	/*
	112	* Get an aligned pointer to a value. This is meant
	113	* as a helper to pass an aligned pointer to a member in a packed structure
	114	* to a function.
	115	*/
	116	#define ALIGNED_CONST_PTR(value) (((const typeof(value) []) { value }))
	117
	118	/*
	119	* lttng_strncpy returns 0 on success, or nonzero on failure.
	120	* It checks that the @src string fits into @dst_len before performing
	121	* the copy. On failure, no copy has been performed.
	122	*
	123	* dst_len includes the string's trailing NULL.
	124	*/
	125	static inline
	126	int lttng_strncpy(char dst, const char src, size_t dst_len)
	127	{
	128	if (lttng_strnlen(src, dst_len) >= dst_len) {
	129	/* Fail since copying would result in truncation. */
	130	return -1;
	131	}
	132	strcpy(dst, src);
	133	return 0;
	134	}
	135
	136	#endif /* _MACROS_H */