summaryrefslogtreecommitdiff
path: root/src/basic/alloc-util.h
blob: bae6a284513d98ac806b38cf7f3170d1e354e447 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
/* SPDX-License-Identifier: LGPL-2.1+ */
#pragma once

/***
  This file is part of systemd.

  Copyright 2010 Lennart Poettering
***/

#include <alloca.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>

#include "macro.h"

#define new(t, n) ((t*) malloc_multiply(sizeof(t), (n)))

#define new0(t, n) ((t*) calloc((n), sizeof(t)))

#define newa(t, n)                                              \
        ({                                                      \
                assert(!size_multiply_overflow(sizeof(t), n));  \
                (t*) alloca(sizeof(t)*(n));                     \
        })

#define newa0(t, n)                                             \
        ({                                                      \
                assert(!size_multiply_overflow(sizeof(t), n));  \
                (t*) alloca0(sizeof(t)*(n));                    \
        })

#define newdup(t, p, n) ((t*) memdup_multiply(p, sizeof(t), (n)))

#define newdup_suffix0(t, p, n) ((t*) memdup_suffix0_multiply(p, sizeof(t), (n)))

#define malloc0(n) (calloc(1, (n)))

static inline void *mfree(void *memory) {
        free(memory);
        return NULL;
}

#define free_and_replace(a, b)                  \
        ({                                      \
                free(a);                        \
                (a) = (b);                      \
                (b) = NULL;                     \
                0;                              \
        })

void* memdup(const void *p, size_t l) _alloc_(2);
void* memdup_suffix0(const void *p, size_t l) _alloc_(2);

static inline void freep(void *p) {
        free(*(void**) p);
}

#define _cleanup_free_ _cleanup_(freep)

static inline bool size_multiply_overflow(size_t size, size_t need) {
        return _unlikely_(need != 0 && size > (SIZE_MAX / need));
}

_malloc_  _alloc_(1, 2) static inline void *malloc_multiply(size_t size, size_t need) {
        if (size_multiply_overflow(size, need))
                return NULL;

        return malloc(size * need);
}

#if !HAVE_REALLOCARRAY
_alloc_(2, 3) static inline void *reallocarray(void *p, size_t need, size_t size) {
        if (size_multiply_overflow(size, need))
                return NULL;

        return realloc(p, size * need);
}
#endif

_alloc_(2, 3) static inline void *memdup_multiply(const void *p, size_t size, size_t need) {
        if (size_multiply_overflow(size, need))
                return NULL;

        return memdup(p, size * need);
}

_alloc_(2, 3) static inline void *memdup_suffix0_multiply(const void *p, size_t size, size_t need) {
        if (size_multiply_overflow(size, need))
                return NULL;

        return memdup_suffix0(p, size * need);
}

void* greedy_realloc(void **p, size_t *allocated, size_t need, size_t size);
void* greedy_realloc0(void **p, size_t *allocated, size_t need, size_t size);

#define GREEDY_REALLOC(array, allocated, need)                          \
        greedy_realloc((void**) &(array), &(allocated), (need), sizeof((array)[0]))

#define GREEDY_REALLOC0(array, allocated, need)                         \
        greedy_realloc0((void**) &(array), &(allocated), (need), sizeof((array)[0]))

#define alloca0(n)                                      \
        ({                                              \
                char *_new_;                            \
                size_t _len_ = n;                       \
                _new_ = alloca(_len_);                  \
                (void *) memset(_new_, 0, _len_);       \
        })

/* It's not clear what alignment glibc/gcc alloca() guarantee, hence provide a guaranteed safe version */
#define alloca_align(size, align)                                       \
        ({                                                              \
                void *_ptr_;                                            \
                size_t _mask_ = (align) - 1;                            \
                _ptr_ = alloca((size) + _mask_);                        \
                (void*)(((uintptr_t)_ptr_ + _mask_) & ~_mask_);         \
        })

#define alloca0_align(size, align)                                      \
        ({                                                              \
                void *_new_;                                            \
                size_t _size_ = (size);                                 \
                _new_ = alloca_align(_size_, (align));                  \
                (void*)memset(_new_, 0, _size_);                        \
        })

/* Takes inspiration from Rusts's Option::take() method: reads and returns a pointer, but at the same time resets it to
 * NULL. See: https://doc.rust-lang.org/std/option/enum.Option.html#method.take */
#define TAKE_PTR(ptr)                           \
        ({                                      \
                typeof(ptr) _ptr_ = (ptr);      \
                (ptr) = NULL;                   \
                _ptr_;                          \
        })