1#include <stdlib.h>
 2#include <stdint.h>
 3#include "libc.h"
 4#include "lock.h"
 5#include "fork_impl.h"
 6
 7#define malloc __libc_malloc
 8#define calloc __libc_calloc
 9#define realloc undef
10#define free undef
11
12/* Ensure that at least 32 atexit handlers can be registered without malloc */
13#define COUNT 32
14
15static struct fl
16{
17	struct fl *next;
18	void (*f[COUNT])(void *);
19	void *a[COUNT];
20} builtin, *head;
21
22static int slot;
23static volatile int lock[1];
24volatile int *const __atexit_lockptr = lock;
25
26void __funcs_on_exit()
27{
28	void (*func)(void *), *arg;
29	LOCK(lock);
30	for (; head; head=head->next, slot=COUNT) while(slot-->0) {
31		func = head->f[slot];
32		arg = head->a[slot];
33		UNLOCK(lock);
34		func(arg);
35		LOCK(lock);
36	}
37}
38
39void __cxa_finalize(void *dso)
40{
41}
42
43int __cxa_atexit(void (*func)(void *), void *arg, void *dso)
44{
45	LOCK(lock);
46
47	/* Defer initialization of head so it can be in BSS */
48	if (!head) head = &builtin;
49
50	/* If the current function list is full, add a new one */
51	if (slot==COUNT) {
52		struct fl *new_fl = calloc(sizeof(struct fl), 1);
53		if (!new_fl) {
54			UNLOCK(lock);
55			return -1;
56		}
57		new_fl->next = head;
58		head = new_fl;
59		slot = 0;
60	}
61
62	/* Append function to the list. */
63	head->f[slot] = func;
64	head->a[slot] = arg;
65	slot++;
66
67	UNLOCK(lock);
68	return 0;
69}
70
71static void call(void *p)
72{
73	((void (*)(void))(uintptr_t)p)();
74}
75
76int atexit(void (*func)(void))
77{
78	return __cxa_atexit(call, (void *)(uintptr_t)func, 0);
79}