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

/*
 * Copyright (C) 2011 EfficiOS Inc.
 * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * SPDX-License-Identifier: GPL-2.0-only
 *
 */

#ifndef _MACROS_H
#define _MACROS_H

#include <common/compat/string.hpp>

#include <stddef.h>
#include <stdlib.h>
#include <string.h>

#include <type_traits>

/*
 * 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))

#ifdef NDEBUG
/*
* Force usage of the assertion condition to prevent unused variable warnings
* when `assert()` are disabled by the `NDEBUG` definition.
*/
# define LTTNG_ASSERT(_cond) ((void) sizeof((void) (_cond), 0))
#else
# include <assert.h>
# define LTTNG_ASSERT(_cond) assert(_cond)
#endif

/*
 * Memory allocation zeroed
 */

static inline
void *zmalloc_internal(size_t size)
{
	return calloc(1, size);
}

template <typename T>
struct can_malloc
{
	/*
	 * gcc versions before 5.0 lack some type traits defined in C++11.
	 * Since in this instance we use the trait to prevent misuses
	 * of malloc (and statically assert) and not to generate different
	 * code based on this property, simply set value to true and allow
	 * the code to compile. Anyone using a contemporary compiler will
	 * catch the error.
	 */
#if __GNUG__ && __GNUC__ < 5
	static constexpr bool value = true;
#else
	static constexpr bool value = std::is_trivially_constructible<T>::value;
#endif
};

/*
 * Malloc and zero-initialize an object of type T, asserting that T can be
 * safely malloc-ed (is trivially constructible).
 */
template<typename T>
T *zmalloc()
{
	static_assert (can_malloc<T>::value, "type can be malloc'ed");
	return (T *) zmalloc_internal(sizeof(T));
}

/*
 * Malloc and zero-initialize a buffer of size `size`, asserting that type T
 * can be safely malloc-ed (is trivially constructible).
 */
template<typename T>
T *zmalloc(size_t size)
{
	static_assert (can_malloc<T>::value, "type can be malloc'ed");
	LTTNG_ASSERT(size >= sizeof(T));
	return (T *) zmalloc_internal(size);
}

/*
 * Malloc and zero-initialize an array of `nmemb` elements of type T,
 * asserting that T can be safely malloc-ed (is trivially constructible).
 */
template<typename T>
T *calloc(size_t nmemb)
{
	static_assert (can_malloc<T>::value, "type can be malloc'ed");
	return (T *) zmalloc_internal(nmemb * sizeof(T));
}

/*
 * Malloc an object of type T, asserting that T can be safely malloc-ed (is
 * trivially constructible).
 */
template<typename T>
T *malloc()
{
	static_assert (can_malloc<T>::value, "type can be malloc'ed");
	return (T *) malloc(sizeof(T));
}

/*
 * Malloc a buffer of size `size`, asserting that type T can be safely
 * malloc-ed (is trivially constructible).
 */
template<typename T>
T *malloc(size_t size)
{
	static_assert (can_malloc<T>::value, "type can be malloc'ed");
	return (T *) malloc(size);
}

/*
 * Prevent using `free` on types that are non-POD.
 *
 * Declare a delete prototype of free if the parameter type is not safe to free
 * (non-POD).
 *
 * If the parameter is a pointer to void, we can't check if what is pointed
 * to is safe to free or not, as we don't know what is pointed to.  Ideally,
 * all calls to free would be with a typed pointer, but there are too many
 * instances of passing a pointer to void to enforce that right now.  So allow
 * pointers to void, these will not be checked.
 */

template<typename T>
struct can_free
{
	/*
	 * gcc versions before 5.0 lack some type traits defined in C++11.
	 * Since in this instance we use the trait to prevent misuses
	 * of free (and statically assert) and not to generate different
	 * code based on this property, simply set value to true and allow
	 * the code to compile. Anyone using a contemporary compiler will
	 * catch the error.
	 */
#if __GNUG__ && __GNUC__ < 5
	static constexpr bool value = true;
#else
	static constexpr bool value = std::is_trivially_destructible<T>::value || std::is_void<T>::value;
#endif
};

template<typename T, typename = typename std::enable_if<!can_free<T>::value>::type>
void free(T *p) = delete;

template<typename T>
struct can_memset
{
	static constexpr bool value = std::is_pod<T>::value || std::is_void<T>::value;
};

template <typename T, typename = typename std::enable_if<!can_memset<T>::value>::type>
void *memset(T *s, int c, size_t n) = delete;

template<typename T>
struct can_memcpy
{
	/*
	 * gcc versions before 5.0 lack some type traits defined in C++11.
	 * Since in this instance we use the trait to prevent misuses
	 * of memcpy (and statically assert) and not to generate different
	 * code based on this property, simply set value to true and allow
	 * the code to compile. Anyone using a contemporary compiler will
	 * catch the error.
	 */
#if __GNUG__ && __GNUC__ < 5
	static constexpr bool value = true;
#else
	static constexpr bool value = std::is_trivially_copyable<T>::value;
#endif
};

template <typename T, typename U,
		typename = typename std::enable_if<!can_memcpy<T>::value>::type,
		typename = typename std::enable_if<!can_memcpy<U>::value>::type>
void *memcpy(T *d, const U *s, size_t n) = delete;

template<typename T>
struct can_memmove
{
	/*
	 * gcc versions before 5.0 lack some type traits defined in C++11.
	 * Since in this instance we use the trait to prevent misuses
	 * of memmove (and statically assert) and not to generate different
	 * code based on this property, simply set value to true and allow
	 * the code to compile. Anyone using a contemporary compiler will
	 * catch the error.
	 */
#if __GNUG__ && __GNUC__ < 5
	static constexpr bool value = true;
#else
	static constexpr bool value = std::is_trivially_copyable<T>::value;
#endif
};

template <typename T, typename U,
		typename = typename std::enable_if<!can_memmove<T>::value>::type,
		typename = typename std::enable_if<!can_memmove<U>::value>::type>
void *memmove(T *d, const U *s, size_t n) = delete;

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

#define ASSERT_LOCKED(lock) LTTNG_ASSERT(pthread_mutex_trylock(&lock))
#define ASSERT_RCU_READ_LOCKED(lock) LTTNG_ASSERT(rcu_read_ongoing())

/* Attribute suitable to tag functions as having printf()-like arguments. */
#define ATTR_FORMAT_PRINTF(_string_index, _first_to_check) \
	__attribute__((format(printf, _string_index, _first_to_check)))

/* Attribute suitable to tag functions as having strftime()-like arguments. */
#define ATTR_FORMAT_STRFTIME(_string_index) \
	__attribute__((format(strftime, _string_index, 0)))

/* Macros used to ignore specific compiler diagnostics. */

#define DIAGNOSTIC_PUSH _Pragma("GCC diagnostic push")
#define DIAGNOSTIC_POP _Pragma("GCC diagnostic pop")

#if defined(__clang__)
  /* Clang */
# define DIAGNOSTIC_IGNORE_SUGGEST_ATTRIBUTE_FORMAT
# define DIAGNOSTIC_IGNORE_FORMAT_NONLITERAL \
	_Pragma("GCC diagnostic ignored \"-Wformat-nonliteral\"")
# define DIAGNOSTIC_IGNORE_LOGICAL_OP
# define DIAGNOSTIC_IGNORE_DUPLICATED_BRANCHES
#else
  /* GCC */
# define DIAGNOSTIC_IGNORE_SUGGEST_ATTRIBUTE_FORMAT \
	_Pragma("GCC diagnostic ignored \"-Wsuggest-attribute=format\"")
# define DIAGNOSTIC_IGNORE_FORMAT_NONLITERAL \
	_Pragma("GCC diagnostic ignored \"-Wformat-nonliteral\"")
# define DIAGNOSTIC_IGNORE_LOGICAL_OP \
	_Pragma("GCC diagnostic ignored \"-Wlogical-op\"")
# define DIAGNOSTIC_IGNORE_DUPLICATED_BRANCHES \
	_Pragma("GCC diagnostic ignored \"-Wduplicated-branches\"")
#endif

/* Used to make specific C++ functions to C code. */
#ifdef __cplusplus
#define C_LINKAGE extern "C"
#else
#define C_LINKAGE
#endif

/*
 * 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.
 *
 * Assumes that 'src' is null-terminated.
 *
 * dst_len includes the string's trailing NULL.
 */
static inline
int lttng_strncpy(char *dst, const char *src, size_t dst_len)
{
	if (strlen(src) >= dst_len) {
		/* Fail since copying would result in truncation. */
		return -1;
	}
	strcpy(dst, src);
	return 0;
}

#endif /* _MACROS_H */
Commit	Line	Data
990570ed	1	/*
21cf9b6b	2	* Copyright (C) 2011 EfficiOS Inc.
ab5be9fa	3	* Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
990570ed	4	*
ab5be9fa	5	* SPDX-License-Identifier: GPL-2.0-only
990570ed	6	*
990570ed DG	7	*/
	8
	9	#ifndef _MACROS_H
	10	#define _MACROS_H
	11
64803277 SM	12	#include <common/compat/string.hpp>
64803277 SM	13
93375aa6	14	#include <stddef.h>
64803277	15	#include <stdlib.h>
f6835b82	16	#include <string.h>
64803277 SM	17
64803277 SM	18	#include <type_traits>
990570ed DG	19
	20	/*
	21	* Takes a pointer x and transform it so we can use it to access members
	22	* without a function call. Here an example:
	23	*
	24	* #define GET_SIZE(x) LTTNG_REF(x)->size
	25	*
	26	* struct { int size; } s;
	27	*
	28	* printf("size : %d\n", GET_SIZE(&s));
	29	*
	30	* For this example we can't use something like this for compatibility purpose
	31	* since this will fail:
	32	*
	33	* #define GET_SIZE(x) x->size;
	34	*
	35	* This is mostly use for the compatibility layer of lttng-tools. See
	36	* poll/epoll for a good example. Since x can be on the stack or allocated
	37	* memory using malloc(), we must use generic accessors for compat in order to
	38	* not use a function to access members and not the variable name.
	39	*/
	40	#define LTTNG_REF(x) ((typeof(x) )(x))
	41
64803277 SM	42	#ifdef NDEBUG
	43	/*
	44	* Force usage of the assertion condition to prevent unused variable warnings
	45	* when `assert()` are disabled by the `NDEBUG` definition.
	46	*/
	47	# define LTTNG_ASSERT(_cond) ((void) sizeof((void) (_cond), 0))
	48	#else
	49	# include <assert.h>
	50	# define LTTNG_ASSERT(_cond) assert(_cond)
	51	#endif
	52
990570ed DG	53	/*
	54	* Memory allocation zeroed
	55	*/
64803277	56
4616a46c	57	static inline
64803277 SM	58	void *zmalloc_internal(size_t size)
	59	{
	60	return calloc(1, size);
	61	}
	62
	63	template <typename T>
	64	struct can_malloc
	65	{
f12e33ba JG	66	/*
	67	* gcc versions before 5.0 lack some type traits defined in C++11.
	68	* Since in this instance we use the trait to prevent misuses
	69	* of malloc (and statically assert) and not to generate different
	70	* code based on this property, simply set value to true and allow
	71	* the code to compile. Anyone using a contemporary compiler will
	72	* catch the error.
	73	*/
	74	#if __GNUG__ && __GNUC__ < 5
	75	static constexpr bool value = true;
	76	#else
64803277	77	static constexpr bool value = std::is_trivially_constructible<T>::value;
f12e33ba	78	#endif
64803277 SM	79	};
	80
	81	/*
	82	* Malloc and zero-initialize an object of type T, asserting that T can be
	83	* safely malloc-ed (is trivially constructible).
	84	*/
	85	template<typename T>
	86	T *zmalloc()
	87	{
	88	static_assert (can_malloc<T>::value, "type can be malloc'ed");
	89	return (T *) zmalloc_internal(sizeof(T));
	90	}
	91
	92	/*
	93	* Malloc and zero-initialize a buffer of size `size`, asserting that type T
	94	* can be safely malloc-ed (is trivially constructible).
	95	*/
	96	template<typename T>
	97	T *zmalloc(size_t size)
	98	{
	99	static_assert (can_malloc<T>::value, "type can be malloc'ed");
	100	LTTNG_ASSERT(size >= sizeof(T));
	101	return (T *) zmalloc_internal(size);
	102	}
	103
	104	/*
	105	* Malloc and zero-initialize an array of `nmemb` elements of type T,
	106	* asserting that T can be safely malloc-ed (is trivially constructible).
	107	*/
	108	template<typename T>
	109	T *calloc(size_t nmemb)
	110	{
	111	static_assert (can_malloc<T>::value, "type can be malloc'ed");
	112	return (T ) zmalloc_internal(nmemb sizeof(T));
	113	}
	114
	115	/*
	116	* Malloc an object of type T, asserting that T can be safely malloc-ed (is
	117	* trivially constructible).
	118	*/
	119	template<typename T>
	120	T *malloc()
4616a46c	121	{
64803277 SM	122	static_assert (can_malloc<T>::value, "type can be malloc'ed");
64803277 SM	123	return (T *) malloc(sizeof(T));
4616a46c	124	}
990570ed	125
64803277 SM	126	/*
	127	* Malloc a buffer of size `size`, asserting that type T can be safely
	128	* malloc-ed (is trivially constructible).
	129	*/
	130	template<typename T>
	131	T *malloc(size_t size)
	132	{
	133	static_assert (can_malloc<T>::value, "type can be malloc'ed");
	134	return (T *) malloc(size);
	135	}
	136
	137	/*
	138	* Prevent using `free` on types that are non-POD.
	139	*
	140	* Declare a delete prototype of free if the parameter type is not safe to free
	141	* (non-POD).
	142	*
	143	* If the parameter is a pointer to void, we can't check if what is pointed
	144	* to is safe to free or not, as we don't know what is pointed to. Ideally,
	145	* all calls to free would be with a typed pointer, but there are too many
	146	* instances of passing a pointer to void to enforce that right now. So allow
	147	* pointers to void, these will not be checked.
	148	*/
	149
	150	template<typename T>
a8e336c2	151	struct can_free
64803277	152	{
f12e33ba JG	153	/*
	154	* gcc versions before 5.0 lack some type traits defined in C++11.
	155	* Since in this instance we use the trait to prevent misuses
	156	* of free (and statically assert) and not to generate different
	157	* code based on this property, simply set value to true and allow
	158	* the code to compile. Anyone using a contemporary compiler will
	159	* catch the error.
	160	*/
	161	#if __GNUG__ && __GNUC__ < 5
	162	static constexpr bool value = true;
	163	#else
a8e336c2	164	static constexpr bool value = std::is_trivially_destructible<T>::value \|\| std::is_void<T>::value;
f12e33ba	165	#endif
64803277 SM	166	};
64803277 SM	167
a8e336c2	168	template<typename T, typename = typename std::enable_if<!can_free<T>::value>::type>
64803277 SM	169	void free(T *p) = delete;
64803277 SM	170
a8e336c2 SM	171	template<typename T>
	172	struct can_memset
	173	{
	174	static constexpr bool value = std::is_pod<T>::value \|\| std::is_void<T>::value;
	175	};
	176
	177	template <typename T, typename = typename std::enable_if<!can_memset<T>::value>::type>
	178	void memset(T s, int c, size_t n) = delete;
	179
	180	template<typename T>
	181	struct can_memcpy
	182	{
f12e33ba JG	183	/*
	184	* gcc versions before 5.0 lack some type traits defined in C++11.
	185	* Since in this instance we use the trait to prevent misuses
	186	* of memcpy (and statically assert) and not to generate different
	187	* code based on this property, simply set value to true and allow
	188	* the code to compile. Anyone using a contemporary compiler will
	189	* catch the error.
	190	*/
	191	#if __GNUG__ && __GNUC__ < 5
	192	static constexpr bool value = true;
	193	#else
a8e336c2	194	static constexpr bool value = std::is_trivially_copyable<T>::value;
f12e33ba	195	#endif
a8e336c2 SM	196	};
	197
	198	template <typename T, typename U,
	199	typename = typename std::enable_if<!can_memcpy<T>::value>::type,
	200	typename = typename std::enable_if<!can_memcpy<U>::value>::type>
	201	void memcpy(T d, const U *s, size_t n) = delete;
	202
	203	template<typename T>
	204	struct can_memmove
	205	{
f12e33ba JG	206	/*
	207	* gcc versions before 5.0 lack some type traits defined in C++11.
	208	* Since in this instance we use the trait to prevent misuses
	209	* of memmove (and statically assert) and not to generate different
	210	* code based on this property, simply set value to true and allow
	211	* the code to compile. Anyone using a contemporary compiler will
	212	* catch the error.
	213	*/
	214	#if __GNUG__ && __GNUC__ < 5
	215	static constexpr bool value = true;
	216	#else
a8e336c2	217	static constexpr bool value = std::is_trivially_copyable<T>::value;
f12e33ba	218	#endif
a8e336c2 SM	219	};
	220
	221	template <typename T, typename U,
	222	typename = typename std::enable_if<!can_memmove<T>::value>::type,
	223	typename = typename std::enable_if<!can_memmove<U>::value>::type>
	224	void memmove(T d, const U *s, size_t n) = delete;
	225
990570ed DG	226	#ifndef ARRAY_SIZE
	227	#define ARRAY_SIZE(array) (sizeof(array) / (sizeof((array)[0])))
	228	#endif
	229
93375aa6 JG	230	#ifndef container_of
	231	#define container_of(ptr, type, member) \
	232	({ \
	233	const typeof(((type )NULL)->member) __ptr = (ptr); \
	234	(type )((char )__ptr - offsetof(type, member)); \
	235	})
	236	#endif
	237
54c90d10 DG	238	#ifndef LTTNG_PACKED
	239	#define LTTNG_PACKED __attribute__((__packed__))
	240	#endif
	241
1405051a FD	242	#ifndef LTTNG_NO_SANITIZE_ADDRESS
	243	#if defined(__clang__) \|\| defined (__GNUC__)
	244	#define LTTNG_NO_SANITIZE_ADDRESS __attribute__((no_sanitize_address))
	245	#else
	246	#define LTTNG_NO_SANITIZE_ADDRESS
	247	#endif
	248	#endif
	249
f8f3885c MD	250	#define member_sizeof(type, field) sizeof(((type *) 0)->field)
f8f3885c MD	251
a0377dfe	252	#define ASSERT_LOCKED(lock) LTTNG_ASSERT(pthread_mutex_trylock(&lock))
48b7cdc2	253	#define ASSERT_RCU_READ_LOCKED(lock) LTTNG_ASSERT(rcu_read_ongoing())
5e5c14ce	254
d22ad5f8 SM	255	/* Attribute suitable to tag functions as having printf()-like arguments. */
	256	#define ATTR_FORMAT_PRINTF(_string_index, _first_to_check) \
	257	__attribute__((format(printf, _string_index, _first_to_check)))
	258
411b3154 SM	259	/* Attribute suitable to tag functions as having strftime()-like arguments. */
	260	#define ATTR_FORMAT_STRFTIME(_string_index) \
	261	__attribute__((format(strftime, _string_index, 0)))
	262
d22ad5f8 SM	263	/* Macros used to ignore specific compiler diagnostics. */
	264
	265	#define DIAGNOSTIC_PUSH _Pragma("GCC diagnostic push")
	266	#define DIAGNOSTIC_POP _Pragma("GCC diagnostic pop")
	267
	268	#if defined(__clang__)
	269	/* Clang */
	270	# define DIAGNOSTIC_IGNORE_SUGGEST_ATTRIBUTE_FORMAT
411b3154 SM	271	# define DIAGNOSTIC_IGNORE_FORMAT_NONLITERAL \
411b3154 SM	272	_Pragma("GCC diagnostic ignored \"-Wformat-nonliteral\"")
942003e5	273	# define DIAGNOSTIC_IGNORE_LOGICAL_OP
05aa7e19	274	# define DIAGNOSTIC_IGNORE_DUPLICATED_BRANCHES
d22ad5f8 SM	275	#else
	276	/* GCC */
	277	# define DIAGNOSTIC_IGNORE_SUGGEST_ATTRIBUTE_FORMAT \
	278	_Pragma("GCC diagnostic ignored \"-Wsuggest-attribute=format\"")
411b3154 SM	279	# define DIAGNOSTIC_IGNORE_FORMAT_NONLITERAL \
411b3154 SM	280	_Pragma("GCC diagnostic ignored \"-Wformat-nonliteral\"")
942003e5 MJ	281	# define DIAGNOSTIC_IGNORE_LOGICAL_OP \
942003e5 MJ	282	_Pragma("GCC diagnostic ignored \"-Wlogical-op\"")
05aa7e19 JG	283	# define DIAGNOSTIC_IGNORE_DUPLICATED_BRANCHES \
05aa7e19 JG	284	_Pragma("GCC diagnostic ignored \"-Wduplicated-branches\"")
d22ad5f8 SM	285	#endif
d22ad5f8 SM	286
d50d200a SM	287	/* Used to make specific C++ functions to C code. */
	288	#ifdef __cplusplus
	289	#define C_LINKAGE extern "C"
	290	#else
	291	#define C_LINKAGE
	292	#endif
	293
f6835b82 MD	294	/*
	295	* lttng_strncpy returns 0 on success, or nonzero on failure.
	296	* It checks that the @src string fits into @dst_len before performing
	297	* the copy. On failure, no copy has been performed.
	298	*
b25a5991 JG	299	* Assumes that 'src' is null-terminated.
b25a5991 JG	300	*
f6835b82 MD	301	* dst_len includes the string's trailing NULL.
	302	*/
	303	static inline
	304	int lttng_strncpy(char dst, const char src, size_t dst_len)
	305	{
b25a5991	306	if (strlen(src) >= dst_len) {
f6835b82 MD	307	/* Fail since copying would result in truncation. */
	308	return -1;
	309	}
c3ef76cd	310	strcpy(dst, src);
f6835b82 MD	311	return 0;
	312	}
	313
990570ed	314	#endif /* _MACROS_H */