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