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#include <stddef.h> #include <stdlib.h> #include <stdint.h> #include <limits.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 int lock[2]; void __funcs_on_exit() { int i; void (*func)(void *), *arg; LOCK(lock); for (; head; head=head->next) for (i=COUNT-1; i>=0; i--) { if (!head->f[i]) continue; 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); } |