src/common: use single Makefile for parallel builds
[lttng-tools.git] / src / common / macros.h
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CommitLineData
1/*
2 * Copyright (C) 2011 EfficiOS Inc.
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 */
42static inline
43void *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 LTTNG_PACKED
61#define LTTNG_PACKED __attribute__((__packed__))
62#endif
63
64#ifndef LTTNG_NO_SANITIZE_ADDRESS
65#if defined(__clang__) || defined (__GNUC__)
66#define LTTNG_NO_SANITIZE_ADDRESS __attribute__((no_sanitize_address))
67#else
68#define LTTNG_NO_SANITIZE_ADDRESS
69#endif
70#endif
71
72#define is_signed(type) (((type) -1) < (type) 1)
73
74#define member_sizeof(type, field) sizeof(((type *) 0)->field)
75
76#define ASSERT_LOCKED(lock) LTTNG_ASSERT(pthread_mutex_trylock(&lock))
77#define ASSERT_RCU_READ_LOCKED(lock) LTTNG_ASSERT(rcu_read_ongoing())
78
79/* Attribute suitable to tag functions as having printf()-like arguments. */
80#define ATTR_FORMAT_PRINTF(_string_index, _first_to_check) \
81 __attribute__((format(printf, _string_index, _first_to_check)))
82
83/* Attribute suitable to tag functions as having strftime()-like arguments. */
84#define ATTR_FORMAT_STRFTIME(_string_index) \
85 __attribute__((format(strftime, _string_index, 0)))
86
87/* Macros used to ignore specific compiler diagnostics. */
88
89#define DIAGNOSTIC_PUSH _Pragma("GCC diagnostic push")
90#define DIAGNOSTIC_POP _Pragma("GCC diagnostic pop")
91
92#if defined(__clang__)
93 /* Clang */
94# define DIAGNOSTIC_IGNORE_SUGGEST_ATTRIBUTE_FORMAT
95# define DIAGNOSTIC_IGNORE_FORMAT_NONLITERAL \
96 _Pragma("GCC diagnostic ignored \"-Wformat-nonliteral\"")
97#else
98 /* GCC */
99# define DIAGNOSTIC_IGNORE_SUGGEST_ATTRIBUTE_FORMAT \
100 _Pragma("GCC diagnostic ignored \"-Wsuggest-attribute=format\"")
101# define DIAGNOSTIC_IGNORE_FORMAT_NONLITERAL \
102 _Pragma("GCC diagnostic ignored \"-Wformat-nonliteral\"")
103#endif
104
105/* Used to make specific C++ functions to C code. */
106#ifdef __cplusplus
107#define C_LINKAGE extern "C"
108#else
109#define C_LINKAGE
110#endif
111
112/*
113 * lttng_strncpy returns 0 on success, or nonzero on failure.
114 * It checks that the @src string fits into @dst_len before performing
115 * the copy. On failure, no copy has been performed.
116 *
117 * dst_len includes the string's trailing NULL.
118 */
119static inline
120int lttng_strncpy(char *dst, const char *src, size_t dst_len)
121{
122 if (lttng_strnlen(src, dst_len) >= dst_len) {
123 /* Fail since copying would result in truncation. */
124 return -1;
125 }
126 strcpy(dst, src);
127 return 0;
128}
129
130#ifdef NDEBUG
131/*
132* Force usage of the assertion condition to prevent unused variable warnings
133* when `assert()` are disabled by the `NDEBUG` definition.
134*/
135# define LTTNG_ASSERT(_cond) ((void) sizeof((void) (_cond), 0))
136#else
137# include <assert.h>
138# define LTTNG_ASSERT(_cond) assert(_cond)
139#endif
140
141#endif /* _MACROS_H */
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