src/basic/alloc-util.h

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 #pragma once
   3
   4 #include <alloca.h>
   5 #include <stddef.h>
   6 #include <stdlib.h>
   7 #include <string.h>
   8
   9 #include "macro.h"
  10
  11 #define new(t, n) ((t*) malloc_multiply(sizeof(t), (n)))
  12
  13 #define new0(t, n) ((t*) calloc((n), sizeof(t)))
  14
  15 #define newa(t, n)                                              \
  16         ({                                                      \
  17                 assert(!size_multiply_overflow(sizeof(t), n));  \
  18                 (t*) alloca(sizeof(t)*(n));                     \
  19         })
  20
  21 #define newa0(t, n)                                             \
  22         ({                                                      \
  23                 assert(!size_multiply_overflow(sizeof(t), n));  \
  24                 (t*) alloca0(sizeof(t)*(n));                    \
  25         })
  26
  27 #define newdup(t, p, n) ((t*) memdup_multiply(p, sizeof(t), (n)))
  28
  29 #define newdup_suffix0(t, p, n) ((t*) memdup_suffix0_multiply(p, sizeof(t), (n)))
  30
  31 #define malloc0(n) (calloc(1, (n)))
  32
  33 static inline void *mfree(void *memory) {
  34         free(memory);
  35         return NULL;
  36 }
  37
  38 #define free_and_replace(a, b)                  \
  39         ({                                      \
  40                 free(a);                        \
  41                 (a) = (b);                      \
  42                 (b) = NULL;                     \
  43                 0;                              \
  44         })
  45
  46 void* memdup(const void *p, size_t l) _alloc_(2);
  47 void* memdup_suffix0(const void *p, size_t l) _alloc_(2);
  48
  49 static inline void freep(void *p) {
  50         free(*(void**) p);
  51 }
  52
  53 #define _cleanup_free_ _cleanup_(freep)
  54
  55 static inline bool size_multiply_overflow(size_t size, size_t need) {
  56         return _unlikely_(need != 0 && size > (SIZE_MAX / need));
  57 }
  58
  59 _malloc_  _alloc_(1, 2) static inline void *malloc_multiply(size_t size, size_t need) {
  60         if (size_multiply_overflow(size, need))
  61                 return NULL;
  62
  63         return malloc(size * need);
  64 }
  65
  66 #if !HAVE_REALLOCARRAY
  67 _alloc_(2, 3) static inline void *reallocarray(void *p, size_t need, size_t size) {
  68         if (size_multiply_overflow(size, need))
  69                 return NULL;
  70
  71         return realloc(p, size * need);
  72 }
  73 #endif
  74
  75 _alloc_(2, 3) static inline void *memdup_multiply(const void *p, size_t size, size_t need) {
  76         if (size_multiply_overflow(size, need))
  77                 return NULL;
  78
  79         return memdup(p, size * need);
  80 }
  81
  82 _alloc_(2, 3) static inline void *memdup_suffix0_multiply(const void *p, size_t size, size_t need) {
  83         if (size_multiply_overflow(size, need))
  84                 return NULL;
  85
  86         return memdup_suffix0(p, size * need);
  87 }
  88
  89 void* greedy_realloc(void **p, size_t *allocated, size_t need, size_t size);
  90 void* greedy_realloc0(void **p, size_t *allocated, size_t need, size_t size);
  91
  92 #define GREEDY_REALLOC(array, allocated, need)                          \
  93         greedy_realloc((void**) &(array), &(allocated), (need), sizeof((array)[0]))
  94
  95 #define GREEDY_REALLOC0(array, allocated, need)                         \
  96         greedy_realloc0((void**) &(array), &(allocated), (need), sizeof((array)[0]))
  97
  98 #define alloca0(n)                                      \
  99         ({                                              \
 100                 char *_new_;                            \
 101                 size_t _len_ = n;                       \
 102                 _new_ = alloca(_len_);                  \
 103                 (void *) memset(_new_, 0, _len_);       \
 104         })
 105
 106 /* It's not clear what alignment glibc/gcc alloca() guarantee, hence provide a guaranteed safe version */
 107 #define alloca_align(size, align)                                       \
 108         ({                                                              \
 109                 void *_ptr_;                                            \
 110                 size_t _mask_ = (align) - 1;                            \
 111                 _ptr_ = alloca((size) + _mask_);                        \
 112                 (void*)(((uintptr_t)_ptr_ + _mask_) & ~_mask_);         \
 113         })
 114
 115 #define alloca0_align(size, align)                                      \
 116         ({                                                              \
 117                 void *_new_;                                            \
 118                 size_t _size_ = (size);                                 \
 119                 _new_ = alloca_align(_size_, (align));                  \
 120                 (void*)memset(_new_, 0, _size_);                        \
 121         })
 122
 123 /* Takes inspiration from Rusts's Option::take() method: reads and returns a pointer, but at the same time resets it to
 124  * NULL. See: https://doc.rust-lang.org/std/option/enum.Option.html#method.take */
 125 #define TAKE_PTR(ptr)                           \
 126         ({                                      \
 127                 typeof(ptr) _ptr_ = (ptr);      \
 128                 (ptr) = NULL;                   \
 129                 _ptr_;                          \
 130         })