musl-tcc/src/exit/atexit.c
2022-03-20 16:48:53 +08:00

80 lines
1.4 KiB
C

#include <stdlib.h>
#include <stdint.h>
#include "libc.h"
#include "lock.h"
#include "fork_impl.h"
#define malloc __libc_malloc
#define calloc __libc_calloc
#define realloc undef
#define free undef
/* 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 int slot;
static volatile int lock[1];
volatile int *const __atexit_lockptr = lock;
void __funcs_on_exit()
{
void (*func)(void *), *arg;
LOCK(lock);
for (; head; head=head->next, slot=COUNT) while(slot-->0) {
func = head->f[slot];
arg = head->a[slot];
UNLOCK(lock);
func(arg);
LOCK(lock);
}
}
void __cxa_finalize(void *dso)
{
}
int __cxa_atexit(void (*func)(void *), void *arg, void *dso)
{
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 (slot==COUNT) {
struct fl *new_fl = calloc(sizeof(struct fl), 1);
if (!new_fl) {
UNLOCK(lock);
return -1;
}
new_fl->next = head;
head = new_fl;
slot = 0;
}
/* Append function to the list. */
head->f[slot] = func;
head->a[slot] = arg;
slot++;
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);
}