src/common/macros.hpp

   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 <memory>
  19 #include <pthread.h>
  20 #include <type_traits>
  21
  22 /*
  23  * Takes a pointer x and transform it so we can use it to access members
  24  * without a function call. Here an example:
  25  *
  26  *    #define GET_SIZE(x) LTTNG_REF(x)->size
  27  *
  28  *    struct { int size; } s;
  29  *
  30  *    printf("size : %d\n", GET_SIZE(&s));
  31  *
  32  * For this example we can't use something like this for compatibility purpose
  33  * since this will fail:
  34  *
  35  *    #define GET_SIZE(x) x->size;
  36  *
  37  * This is mostly use for the compatibility layer of lttng-tools. See
  38  * poll/epoll for a good example. Since x can be on the stack or allocated
  39  * memory using malloc(), we must use generic accessors for compat in order to
  40  * *not* use a function to access members and not the variable name.
  41  */
  42 #define LTTNG_REF(x) ((typeof(*(x)) *) (x))
  43
  44 #ifdef NDEBUG
  45 /*
  46 * Force usage of the assertion condition to prevent unused variable warnings
  47 * when `assert()` are disabled by the `NDEBUG` definition.
  48 */
  49 # define LTTNG_ASSERT(_cond) ((void) sizeof((void) (_cond), 0))
  50 #else
  51 # include <assert.h>
  52 # define LTTNG_ASSERT(_cond) assert(_cond)
  53 #endif
  54
  55 /*
  56  * Memory allocation zeroed
  57  */
  58
  59 static inline
  60 void *zmalloc_internal(size_t size)
  61 {
  62         return calloc(1, size);
  63 }
  64
  65 template <typename MallocableType>
  66 struct can_malloc {
  67         /*
  68          * gcc versions before 5.0 lack some type traits defined in C++11.
  69          * Since in this instance we use the trait to prevent misuses
  70          * of malloc (and statically assert) and not to generate different
  71          * code based on this property, simply set value to true and allow
  72          * the code to compile. Anyone using a contemporary compiler will
  73          * catch the error.
  74          */
  75 #if __GNUG__ && __GNUC__ < 5
  76         static constexpr bool value = true;
  77 #else
  78         static constexpr bool value = std::is_trivially_constructible<MallocableType>::value;
  79 #endif
  80 };
  81
  82 /*
  83  * Malloc and zero-initialize an object of type T, asserting that MallocableType can be
  84  * safely malloc-ed (is trivially constructible).
  85  */
  86 template <typename MallocableType>
  87 MallocableType *zmalloc()
  88 {
  89         static_assert(can_malloc<MallocableType>::value, "type can be malloc'ed");
  90         return (MallocableType *) zmalloc_internal(sizeof(MallocableType)); /* NOLINT sizeof
  91                                                                                potentially used on a
  92                                                                                pointer. */
  93 }
  94
  95 /*
  96  * Malloc and zero-initialize a buffer of size `size`, asserting that type AllocatedType
  97  * can be safely malloc-ed (is trivially constructible).
  98  */
  99 template <typename AllocatedType>
 100 AllocatedType *zmalloc(size_t size)
 101 {
 102         static_assert(can_malloc<AllocatedType>::value, "type can be malloc'ed");
 103         LTTNG_ASSERT(size >= sizeof(AllocatedType));
 104         return (AllocatedType *) zmalloc_internal(size);
 105 }
 106
 107 /*
 108  * Malloc and zero-initialize an array of `nmemb` elements of type AllocatedType,
 109  * asserting that AllocatedType can be safely malloc-ed (is trivially constructible).
 110  */
 111 template <typename AllocatedType>
 112 AllocatedType *calloc(size_t nmemb)
 113 {
 114         static_assert(can_malloc<AllocatedType>::value, "type can be malloc'ed");
 115         return (AllocatedType *) zmalloc_internal(nmemb * sizeof(AllocatedType)); /* NOLINT sizeof
 116                                                                                      potentially
 117                                                                                      used on a
 118                                                                                      pointer. */
 119 }
 120
 121 /*
 122  * Malloc an object of type AllocatedType, asserting that AllocatedType can be safely malloc-ed (is
 123  * trivially constructible).
 124  */
 125 template <typename AllocatedType>
 126 AllocatedType *malloc()
 127 {
 128         static_assert(can_malloc<AllocatedType>::value, "type can be malloc'ed");
 129         return (AllocatedType *) malloc(sizeof(AllocatedType));
 130 }
 131
 132 /*
 133  * Malloc a buffer of size `size`, asserting that AllocatedType can be safely
 134  * malloc-ed (is trivially constructible).
 135  */
 136 template<typename AllocatedType>
 137 AllocatedType *malloc(size_t size)
 138 {
 139         static_assert (can_malloc<AllocatedType>::value, "type can be malloc'ed");
 140         return (AllocatedType *) malloc(size);
 141 }
 142
 143 /*
 144  * Prevent using `free` on types that are non-POD.
 145  *
 146  * Declare a delete prototype of free if the parameter type is not safe to free
 147  * (non-POD).
 148  *
 149  * If the parameter is a pointer to void, we can't check if what is pointed
 150  * to is safe to free or not, as we don't know what is pointed to.  Ideally,
 151  * all calls to free would be with a typed pointer, but there are too many
 152  * instances of passing a pointer to void to enforce that right now.  So allow
 153  * pointers to void, these will not be checked.
 154  */
 155
 156 template<typename FreedType>
 157 struct can_free
 158 {
 159         /*
 160          * gcc versions before 5.0 lack some type traits defined in C++11.
 161          * Since in this instance we use the trait to prevent misuses
 162          * of free (and statically assert) and not to generate different
 163          * code based on this property, simply set value to true and allow
 164          * the code to compile. Anyone using a contemporary compiler will
 165          * catch the error.
 166          */
 167 #if __GNUG__ && __GNUC__ < 5
 168         static constexpr bool value = true;
 169 #else
 170         static constexpr bool value = std::is_trivially_destructible<FreedType>::value ||
 171                 std::is_void<FreedType>::value;
 172 #endif
 173 };
 174
 175 template <typename FreedType, typename = typename std::enable_if<!can_free<FreedType>::value>::type>
 176 void free(FreedType *p) = delete;
 177
 178 template <typename InitializedType>
 179 struct can_memset {
 180         static constexpr bool value = std::is_pod<InitializedType>::value ||
 181                 std::is_void<InitializedType>::value;
 182 };
 183
 184 template <typename InitializedType,
 185           typename = typename std::enable_if<!can_memset<InitializedType>::value>::type>
 186 void *memset(InitializedType *s, int c, size_t n) = delete;
 187
 188 template<typename T>
 189 struct can_memcpy
 190 {
 191         /*
 192          * gcc versions before 5.0 lack some type traits defined in C++11.
 193          * Since in this instance we use the trait to prevent misuses
 194          * of memcpy (and statically assert) and not to generate different
 195          * code based on this property, simply set value to true and allow
 196          * the code to compile. Anyone using a contemporary compiler will
 197          * catch the error.
 198          */
 199 #if __GNUG__ && __GNUC__ < 5
 200         static constexpr bool value = true;
 201 #else
 202         static constexpr bool value = std::is_trivially_copyable<T>::value;
 203 #endif
 204 };
 205
 206 template <typename DestinationType,
 207           typename SourceType,
 208           typename = typename std::enable_if<!can_memcpy<DestinationType>::value>::type,
 209           typename = typename std::enable_if<!can_memcpy<SourceType>::value>::type>
 210 void *memcpy(DestinationType *d, const SourceType *s, size_t n) = delete;
 211
 212 template <typename MovedType>
 213 struct can_memmove {
 214         /*
 215          * gcc versions before 5.0 lack some type traits defined in C++11.
 216          * Since in this instance we use the trait to prevent misuses
 217          * of memmove (and statically assert) and not to generate different
 218          * code based on this property, simply set value to true and allow
 219          * the code to compile. Anyone using a contemporary compiler will
 220          * catch the error.
 221          */
 222 #if __GNUG__ && __GNUC__ < 5
 223         static constexpr bool value = true;
 224 #else
 225         static constexpr bool value = std::is_trivially_copyable<MovedType>::value;
 226 #endif
 227 };
 228
 229 template <typename DestinationType,
 230           typename SourceType,
 231           typename = typename std::enable_if<!can_memmove<DestinationType>::value>::type,
 232           typename = typename std::enable_if<!can_memmove<SourceType>::value>::type>
 233 void *memmove(DestinationType *d, const SourceType *s, size_t n) = delete;
 234
 235 #ifndef ARRAY_SIZE
 236 #define ARRAY_SIZE(array)   (sizeof(array) / (sizeof((array)[0])))
 237 #endif
 238
 239 #ifndef LTTNG_PACKED
 240 #define LTTNG_PACKED __attribute__((__packed__))
 241 #endif
 242
 243 #ifndef LTTNG_NO_SANITIZE_ADDRESS
 244 #if defined(__clang__) || defined (__GNUC__)
 245 #define LTTNG_NO_SANITIZE_ADDRESS __attribute__((no_sanitize_address))
 246 #else
 247 #define LTTNG_NO_SANITIZE_ADDRESS
 248 #endif
 249 #endif
 250
 251 #define member_sizeof(type, field)      sizeof(((type *) 0)->field)
 252
 253 #define ASSERT_LOCKED(lock)          LTTNG_ASSERT(pthread_mutex_trylock(&(lock)))
 254 #define ASSERT_RCU_READ_LOCKED() LTTNG_ASSERT(rcu_read_ongoing())
 255 #define ASSERT_RCU_READ_UNLOCKED() LTTNG_ASSERT(!rcu_read_ongoing())
 256
 257 /* Attribute suitable to tag functions as having printf()-like arguments. */
 258 #define ATTR_FORMAT_PRINTF(_string_index, _first_to_check) \
 259         __attribute__((format(printf, _string_index, _first_to_check)))
 260
 261 /* Attribute suitable to tag functions as having strftime()-like arguments. */
 262 #define ATTR_FORMAT_STRFTIME(_string_index) \
 263         __attribute__((format(strftime, _string_index, 0)))
 264
 265 /* Macros used to ignore specific compiler diagnostics. */
 266
 267 #define DIAGNOSTIC_PUSH _Pragma("GCC diagnostic push")
 268 #define DIAGNOSTIC_POP _Pragma("GCC diagnostic pop")
 269
 270 #if defined(__clang__)
 271   /* Clang */
 272 # define DIAGNOSTIC_IGNORE_SUGGEST_ATTRIBUTE_FORMAT
 273 # define DIAGNOSTIC_IGNORE_FORMAT_NONLITERAL \
 274         _Pragma("GCC diagnostic ignored \"-Wformat-nonliteral\"")
 275 # define DIAGNOSTIC_IGNORE_LOGICAL_OP
 276 # define DIAGNOSTIC_IGNORE_DUPLICATED_BRANCHES
 277 # define DIAGNOSTIC_IGNORE_INVALID_OFFSETOF
 278         _Pragma("GCC diagnostic ignored \"-Winvalid-offsetof\"")
 279 #else
 280   /* GCC */
 281 # define DIAGNOSTIC_IGNORE_SUGGEST_ATTRIBUTE_FORMAT \
 282         _Pragma("GCC diagnostic ignored \"-Wsuggest-attribute=format\"")
 283 # define DIAGNOSTIC_IGNORE_FORMAT_NONLITERAL \
 284         _Pragma("GCC diagnostic ignored \"-Wformat-nonliteral\"")
 285 # define DIAGNOSTIC_IGNORE_LOGICAL_OP \
 286         _Pragma("GCC diagnostic ignored \"-Wlogical-op\"")
 287 #if __GNUG__ && __GNUC__ >= 7
 288 # define DIAGNOSTIC_IGNORE_DUPLICATED_BRANCHES                          \
 289         _Pragma("GCC diagnostic ignored \"-Wduplicated-branches\"")
 290 #else
 291 # define DIAGNOSTIC_IGNORE_DUPLICATED_BRANCHES
 292 #endif /* __GNUG__ && __GNUC__ >= 7 */
 293 # define DIAGNOSTIC_IGNORE_INVALID_OFFSETOF                             \
 294         _Pragma("GCC diagnostic ignored \"-Winvalid-offsetof\"")
 295 #endif
 296
 297 /* Used to make specific C++ functions to C code. */
 298 #ifdef __cplusplus
 299 #define C_LINKAGE extern "C"
 300 #else
 301 #define C_LINKAGE
 302 #endif
 303
 304 /*
 305  * lttng_strncpy returns 0 on success, or nonzero on failure.
 306  * It checks that the @src string fits into @dst_len before performing
 307  * the copy. On failure, no copy has been performed.
 308  *
 309  * Assumes that 'src' is null-terminated.
 310  *
 311  * dst_len includes the string's trailing NULL.
 312  */
 313 static inline
 314 int lttng_strncpy(char *dst, const char *src, size_t dst_len)
 315 {
 316         if (strlen(src) >= dst_len) {
 317                 /* Fail since copying would result in truncation. */
 318                 return -1;
 319         }
 320         strcpy(dst, src);
 321         return 0;
 322 }
 323
 324 namespace lttng {
 325 namespace utils {
 326 template <class ParentType, class MemberType>
 327 ParentType *container_of(const MemberType *member, const MemberType ParentType::*ptr_to_member)
 328 {
 329         const ParentType *dummy_parent = nullptr;
 330         auto *offset_of_member = reinterpret_cast<const char *>(&(dummy_parent->*ptr_to_member));
 331         auto address_of_parent = reinterpret_cast<const char *>(member) - offset_of_member;
 332
 333         return reinterpret_cast<ParentType *>(address_of_parent);
 334 }
 335 } /* namespace utils */
 336 } /* namespace lttng */
 337
 338 #endif /* _MACROS_H */