src/basic/alloc-util.h

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 #pragma once
   3
   4 /***
   5   Copyright 2010 Lennart Poettering
   6 ***/
   7
   8 #include <alloca.h>
   9 #include <stddef.h>
  10 #include <stdlib.h>
  11 #include <string.h>
  12
  13 #include "macro.h"
  14
  15 #define new(t, n) ((t*) malloc_multiply(sizeof(t), (n)))
  16
  17 #define new0(t, n) ((t*) calloc((n), sizeof(t)))
  18
  19 #define newa(t, n)                                              \
  20         ({                                                      \
  21                 assert(!size_multiply_overflow(sizeof(t), n));  \
  22                 (t*) alloca(sizeof(t)*(n));                     \
  23         })
  24
  25 #define newa0(t, n)                                             \
  26         ({                                                      \
  27                 assert(!size_multiply_overflow(sizeof(t), n));  \
  28                 (t*) alloca0(sizeof(t)*(n));                    \
  29         })
  30
  31 #define newdup(t, p, n) ((t*) memdup_multiply(p, sizeof(t), (n)))
  32
  33 #define newdup_suffix0(t, p, n) ((t*) memdup_suffix0_multiply(p, sizeof(t), (n)))
  34
  35 #define malloc0(n) (calloc(1, (n)))
  36
  37 static inline void *mfree(void *memory) {
  38         free(memory);
  39         return NULL;
  40 }
  41
  42 #define free_and_replace(a, b)                  \
  43         ({                                      \
  44                 free(a);                        \
  45                 (a) = (b);                      \
  46                 (b) = NULL;                     \
  47                 0;                              \
  48         })
  49
  50 void* memdup(const void *p, size_t l) _alloc_(2);
  51 void* memdup_suffix0(const void *p, size_t l) _alloc_(2);
  52
  53 static inline void freep(void *p) {
  54         free(*(void**) p);
  55 }
  56
  57 #define _cleanup_free_ _cleanup_(freep)
  58
  59 static inline bool size_multiply_overflow(size_t size, size_t need) {
  60         return _unlikely_(need != 0 && size > (SIZE_MAX / need));
  61 }
  62
  63 _malloc_  _alloc_(1, 2) static inline void *malloc_multiply(size_t size, size_t need) {
  64         if (size_multiply_overflow(size, need))
  65                 return NULL;
  66
  67         return malloc(size * need);
  68 }
  69
  70 #if !HAVE_REALLOCARRAY
  71 _alloc_(2, 3) static inline void *reallocarray(void *p, size_t need, size_t size) {
  72         if (size_multiply_overflow(size, need))
  73                 return NULL;
  74
  75         return realloc(p, size * need);
  76 }
  77 #endif
  78
  79 _alloc_(2, 3) static inline void *memdup_multiply(const void *p, size_t size, size_t need) {
  80         if (size_multiply_overflow(size, need))
  81                 return NULL;
  82
  83         return memdup(p, size * need);
  84 }
  85
  86 _alloc_(2, 3) static inline void *memdup_suffix0_multiply(const void *p, size_t size, size_t need) {
  87         if (size_multiply_overflow(size, need))
  88                 return NULL;
  89
  90         return memdup_suffix0(p, size * need);
  91 }
  92
  93 void* greedy_realloc(void **p, size_t *allocated, size_t need, size_t size);
  94 void* greedy_realloc0(void **p, size_t *allocated, size_t need, size_t size);
  95
  96 #define GREEDY_REALLOC(array, allocated, need)                          \
  97         greedy_realloc((void**) &(array), &(allocated), (need), sizeof((array)[0]))
  98
  99 #define GREEDY_REALLOC0(array, allocated, need)                         \
 100         greedy_realloc0((void**) &(array), &(allocated), (need), sizeof((array)[0]))
 101
 102 #define alloca0(n)                                      \
 103         ({                                              \
 104                 char *_new_;                            \
 105                 size_t _len_ = n;                       \
 106                 _new_ = alloca(_len_);                  \
 107                 (void *) memset(_new_, 0, _len_);       \
 108         })
 109
 110 /* It's not clear what alignment glibc/gcc alloca() guarantee, hence provide a guaranteed safe version */
 111 #define alloca_align(size, align)                                       \
 112         ({                                                              \
 113                 void *_ptr_;                                            \
 114                 size_t _mask_ = (align) - 1;                            \
 115                 _ptr_ = alloca((size) + _mask_);                        \
 116                 (void*)(((uintptr_t)_ptr_ + _mask_) & ~_mask_);         \
 117         })
 118
 119 #define alloca0_align(size, align)                                      \
 120         ({                                                              \
 121                 void *_new_;                                            \
 122                 size_t _size_ = (size);                                 \
 123                 _new_ = alloca_align(_size_, (align));                  \
 124                 (void*)memset(_new_, 0, _size_);                        \
 125         })
 126
 127 /* Takes inspiration from Rusts's Option::take() method: reads and returns a pointer, but at the same time resets it to
 128  * NULL. See: https://doc.rust-lang.org/std/option/enum.Option.html#method.take */
 129 #define TAKE_PTR(ptr)                           \
 130         ({                                      \
 131                 typeof(ptr) _ptr_ = (ptr);      \
 132                 (ptr) = NULL;                   \
 133                 _ptr_;                          \
 134         })