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| | #include <stdlib.h>
#include <stdint.h>
#include "libc.h"
/* Ensure that at least 32 atexit handlers can be registered without malloc */
#define COUNT 32
static struct fl
{
struct fl *next;
void (*f[COUNT])(void *);
void *a[COUNT];
} builtin, *head;
static volatile int lock[2];
static int next()
{
int i;
for (; head; head=head->next)
for (i=COUNT-1; i>=0; i--)
if (head->f[i])
return i;
return -1;
}
void __funcs_on_exit()
{
int i;
void (*func)(void *), *arg;
LOCK(lock);
for (;;) {
i = next();
if (i<0) break;
func = head->f[i];
arg = head->a[i];
head->f[i] = 0;
UNLOCK(lock);
func(arg);
LOCK(lock);
}
}
void __cxa_finalize(void *dso)
{
}
int __cxa_atexit(void (*func)(void *), void *arg, void *dso)
{
int i;
LOCK(lock);
/* Defer initialization of head so it can be in BSS */
if (!head) head = &builtin;
/* If the current function list is full, add a new one */
if (head->f[COUNT-1]) {
struct fl *new_fl = calloc(sizeof(struct fl), 1);
if (!new_fl) {
UNLOCK(lock);
return -1;
}
new_fl->next = head;
head = new_fl;
}
/* Append function to the list. */
for (i=0; i<COUNT && head->f[i]; i++);
head->f[i] = func;
head->a[i] = arg;
UNLOCK(lock);
return 0;
}
static void call(void *p)
{
((void (*)(void))(uintptr_t)p)();
}
int atexit(void (*func)(void))
{
return __cxa_atexit(call, (void *)(uintptr_t)func, 0);
}
|