1 /*
2 * Copyright (c) 2012, 2013 ARM Ltd
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. The name of the company may not be used to endorse or promote
14 * products derived from this software without specific prior written
15 * permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY ARM LTD ``AS IS'' AND ANY EXPRESS OR IMPLIED
18 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
19 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL ARM LTD BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
22 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
23 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
24 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
25 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
26 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 #include "nano-malloc.h"
30
31 /*
32 * Algorithm:
33 * Maintain a global free chunk_t single link list, headed by global
34 * variable __malloc_free_list.
35 * When free, insert the to-be-freed chunk_t into free list. The place to
36 * insert should make sure all chunks are sorted by address from low to
37 * high. Then merge with neighbor chunks if adjacent.
38 */
39
40 void
free(void * free_p)41 free (void * free_p)
42 {
43 chunk_t *p_to_free;
44 chunk_t **p, *r;
45
46 if (free_p == NULL) return;
47
48 p_to_free = ptr_to_chunk(free_p);
49 p_to_free->next = NULL;
50
51 #if MALLOC_DEBUG
52 __malloc_validate_block(p_to_free);
53 #endif
54
55 MALLOC_LOCK;
56
57 for (p = &__malloc_free_list; (r = *p) != NULL; p = &r->next)
58 {
59 /* Insert in address order */
60 if (p_to_free <= r) {
61
62 /* Check for double free */
63 if (p_to_free == r)
64 {
65 errno = ENOMEM;
66 goto unlock;
67 }
68
69 break;
70 }
71
72 /* Merge blocks together */
73 if (chunk_after(r) == p_to_free)
74 {
75 *_size_ref(r) += _size(p_to_free);
76 p_to_free = r;
77 r = r->next;
78 goto no_insert;
79 }
80
81 }
82
83 p_to_free->next = r;
84 *p = p_to_free;
85
86 no_insert:
87
88 /* Merge blocks together */
89 if (chunk_after(p_to_free) == r)
90 {
91 #ifdef __GNUC__
92 #pragma GCC diagnostic push
93 #pragma GCC diagnostic ignored "-Wpragmas"
94 #pragma GCC diagnostic ignored "-Wunknown-warning-option"
95 #pragma GCC diagnostic ignored "-Wanalyzer-null-dereference"
96 #endif
97 *_size_ref(p_to_free) += _size(r);
98 #ifdef __GNUC__
99 #pragma GCC diagnostic pop
100 #endif
101 p_to_free->next = r->next;
102 }
103
104 unlock:
105 MALLOC_UNLOCK;
106 }
107
108 #ifdef _HAVE_ALIAS_ATTRIBUTE
109 #ifndef __clang__
110 #pragma GCC diagnostic ignored "-Wmissing-attributes"
111 #endif
112 __strong_reference(free, __malloc_free);
113 __strong_reference(free, cfree);
114 #else
cfree(void * ptr)115 void cfree(void * ptr)
116 {
117 free(ptr);
118 }
119 #endif
120
