| 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 <common/compat/string.hpp> |
| 13 | |
| 14 | #include <stddef.h> |
| 15 | #include <stdlib.h> |
| 16 | #include <string.h> |
| 17 | |
| 18 | #include <type_traits> |
| 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 | |
| 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 | |
| 53 | /* |
| 54 | * Memory allocation zeroed |
| 55 | */ |
| 56 | |
| 57 | static inline |
| 58 | void *zmalloc_internal(size_t size) |
| 59 | { |
| 60 | return calloc(1, size); |
| 61 | } |
| 62 | |
| 63 | template <typename T> |
| 64 | struct can_malloc |
| 65 | { |
| 66 | static constexpr bool value = std::is_trivially_constructible<T>::value; |
| 67 | }; |
| 68 | |
| 69 | /* |
| 70 | * Malloc and zero-initialize an object of type T, asserting that T can be |
| 71 | * safely malloc-ed (is trivially constructible). |
| 72 | */ |
| 73 | template<typename T> |
| 74 | T *zmalloc() |
| 75 | { |
| 76 | static_assert (can_malloc<T>::value, "type can be malloc'ed"); |
| 77 | return (T *) zmalloc_internal(sizeof(T)); |
| 78 | } |
| 79 | |
| 80 | /* |
| 81 | * Malloc and zero-initialize a buffer of size `size`, asserting that type T |
| 82 | * can be safely malloc-ed (is trivially constructible). |
| 83 | */ |
| 84 | template<typename T> |
| 85 | T *zmalloc(size_t size) |
| 86 | { |
| 87 | static_assert (can_malloc<T>::value, "type can be malloc'ed"); |
| 88 | LTTNG_ASSERT(size >= sizeof(T)); |
| 89 | return (T *) zmalloc_internal(size); |
| 90 | } |
| 91 | |
| 92 | /* |
| 93 | * Malloc and zero-initialize an array of `nmemb` elements of type T, |
| 94 | * asserting that T can be safely malloc-ed (is trivially constructible). |
| 95 | */ |
| 96 | template<typename T> |
| 97 | T *calloc(size_t nmemb) |
| 98 | { |
| 99 | static_assert (can_malloc<T>::value, "type can be malloc'ed"); |
| 100 | return (T *) zmalloc_internal(nmemb * sizeof(T)); |
| 101 | } |
| 102 | |
| 103 | /* |
| 104 | * Malloc an object of type T, asserting that T can be safely malloc-ed (is |
| 105 | * trivially constructible). |
| 106 | */ |
| 107 | template<typename T> |
| 108 | T *malloc() |
| 109 | { |
| 110 | static_assert (can_malloc<T>::value, "type can be malloc'ed"); |
| 111 | return (T *) malloc(sizeof(T)); |
| 112 | } |
| 113 | |
| 114 | /* |
| 115 | * Malloc a buffer of size `size`, asserting that type T can be safely |
| 116 | * malloc-ed (is trivially constructible). |
| 117 | */ |
| 118 | template<typename T> |
| 119 | T *malloc(size_t size) |
| 120 | { |
| 121 | static_assert (can_malloc<T>::value, "type can be malloc'ed"); |
| 122 | return (T *) malloc(size); |
| 123 | } |
| 124 | |
| 125 | /* |
| 126 | * Prevent using `free` on types that are non-POD. |
| 127 | * |
| 128 | * Declare a delete prototype of free if the parameter type is not safe to free |
| 129 | * (non-POD). |
| 130 | * |
| 131 | * If the parameter is a pointer to void, we can't check if what is pointed |
| 132 | * to is safe to free or not, as we don't know what is pointed to. Ideally, |
| 133 | * all calls to free would be with a typed pointer, but there are too many |
| 134 | * instances of passing a pointer to void to enforce that right now. So allow |
| 135 | * pointers to void, these will not be checked. |
| 136 | */ |
| 137 | |
| 138 | template<typename T> |
| 139 | struct is_pod_or_void |
| 140 | { |
| 141 | static constexpr bool value = std::is_pod<T>::value || std::is_void<T>::value; |
| 142 | }; |
| 143 | |
| 144 | template<typename T, typename = typename std::enable_if<!is_pod_or_void<T>::value>::type> |
| 145 | void free(T *p) = delete; |
| 146 | |
| 147 | #ifndef ARRAY_SIZE |
| 148 | #define ARRAY_SIZE(array) (sizeof(array) / (sizeof((array)[0]))) |
| 149 | #endif |
| 150 | |
| 151 | #ifndef container_of |
| 152 | #define container_of(ptr, type, member) \ |
| 153 | ({ \ |
| 154 | const typeof(((type *)NULL)->member) * __ptr = (ptr); \ |
| 155 | (type *)((char *)__ptr - offsetof(type, member)); \ |
| 156 | }) |
| 157 | #endif |
| 158 | |
| 159 | #ifndef LTTNG_PACKED |
| 160 | #define LTTNG_PACKED __attribute__((__packed__)) |
| 161 | #endif |
| 162 | |
| 163 | #ifndef LTTNG_NO_SANITIZE_ADDRESS |
| 164 | #if defined(__clang__) || defined (__GNUC__) |
| 165 | #define LTTNG_NO_SANITIZE_ADDRESS __attribute__((no_sanitize_address)) |
| 166 | #else |
| 167 | #define LTTNG_NO_SANITIZE_ADDRESS |
| 168 | #endif |
| 169 | #endif |
| 170 | |
| 171 | #define member_sizeof(type, field) sizeof(((type *) 0)->field) |
| 172 | |
| 173 | #define ASSERT_LOCKED(lock) LTTNG_ASSERT(pthread_mutex_trylock(&lock)) |
| 174 | #define ASSERT_RCU_READ_LOCKED(lock) LTTNG_ASSERT(rcu_read_ongoing()) |
| 175 | |
| 176 | /* Attribute suitable to tag functions as having printf()-like arguments. */ |
| 177 | #define ATTR_FORMAT_PRINTF(_string_index, _first_to_check) \ |
| 178 | __attribute__((format(printf, _string_index, _first_to_check))) |
| 179 | |
| 180 | /* Attribute suitable to tag functions as having strftime()-like arguments. */ |
| 181 | #define ATTR_FORMAT_STRFTIME(_string_index) \ |
| 182 | __attribute__((format(strftime, _string_index, 0))) |
| 183 | |
| 184 | /* Macros used to ignore specific compiler diagnostics. */ |
| 185 | |
| 186 | #define DIAGNOSTIC_PUSH _Pragma("GCC diagnostic push") |
| 187 | #define DIAGNOSTIC_POP _Pragma("GCC diagnostic pop") |
| 188 | |
| 189 | #if defined(__clang__) |
| 190 | /* Clang */ |
| 191 | # define DIAGNOSTIC_IGNORE_SUGGEST_ATTRIBUTE_FORMAT |
| 192 | # define DIAGNOSTIC_IGNORE_FORMAT_NONLITERAL \ |
| 193 | _Pragma("GCC diagnostic ignored \"-Wformat-nonliteral\"") |
| 194 | # define DIAGNOSTIC_IGNORE_LOGICAL_OP |
| 195 | #else |
| 196 | /* GCC */ |
| 197 | # define DIAGNOSTIC_IGNORE_SUGGEST_ATTRIBUTE_FORMAT \ |
| 198 | _Pragma("GCC diagnostic ignored \"-Wsuggest-attribute=format\"") |
| 199 | # define DIAGNOSTIC_IGNORE_FORMAT_NONLITERAL \ |
| 200 | _Pragma("GCC diagnostic ignored \"-Wformat-nonliteral\"") |
| 201 | # define DIAGNOSTIC_IGNORE_LOGICAL_OP \ |
| 202 | _Pragma("GCC diagnostic ignored \"-Wlogical-op\"") |
| 203 | #endif |
| 204 | |
| 205 | /* Used to make specific C++ functions to C code. */ |
| 206 | #ifdef __cplusplus |
| 207 | #define C_LINKAGE extern "C" |
| 208 | #else |
| 209 | #define C_LINKAGE |
| 210 | #endif |
| 211 | |
| 212 | /* |
| 213 | * lttng_strncpy returns 0 on success, or nonzero on failure. |
| 214 | * It checks that the @src string fits into @dst_len before performing |
| 215 | * the copy. On failure, no copy has been performed. |
| 216 | * |
| 217 | * Assumes that 'src' is null-terminated. |
| 218 | * |
| 219 | * dst_len includes the string's trailing NULL. |
| 220 | */ |
| 221 | static inline |
| 222 | int lttng_strncpy(char *dst, const char *src, size_t dst_len) |
| 223 | { |
| 224 | if (strlen(src) >= dst_len) { |
| 225 | /* Fail since copying would result in truncation. */ |
| 226 | return -1; |
| 227 | } |
| 228 | strcpy(dst, src); |
| 229 | return 0; |
| 230 | } |
| 231 | |
| 232 | #endif /* _MACROS_H */ |