LibC: Make {,__cxa_}atexit thread safe

This commit is contained in:
Bananymous 2025-08-03 21:47:35 +03:00
parent 284c9e5f61
commit 0e0f5295cf
1 changed files with 39 additions and 4 deletions

View File

@ -1,5 +1,7 @@
#include <stddef.h>
#include <limits.h> #include <limits.h>
#include <pthread.h>
#include <stdlib.h>
#include <string.h>
struct atexit_func_entry_t struct atexit_func_entry_t
{ {
@ -8,19 +10,52 @@ struct atexit_func_entry_t
void* dso_handle; void* dso_handle;
}; };
static atexit_func_entry_t s_atexit_funcs[ATEXIT_MAX]; static atexit_func_entry_t s_atexit_funcs_storage[ATEXIT_MAX];
static atexit_func_entry_t* s_atexit_funcs = s_atexit_funcs_storage;
static size_t s_atexit_funcs_capacity = ATEXIT_MAX;
static size_t s_atexit_func_count = 0; static size_t s_atexit_func_count = 0;
static pthread_mutex_t s_atexit_mutex = PTHREAD_MUTEX_INITIALIZER;
extern "C" int __cxa_atexit(void(*func)(void*), void* arg, void* dso_handle) extern "C" int __cxa_atexit(void(*func)(void*), void* arg, void* dso_handle)
{ {
if (s_atexit_func_count >= ATEXIT_MAX) pthread_mutex_lock(&s_atexit_mutex);
return -1;
if (s_atexit_func_count >= s_atexit_funcs_capacity)
{
const size_t new_capacity = s_atexit_funcs_capacity * 2;
void* new_funcs = nullptr;
if (s_atexit_funcs == s_atexit_funcs_storage)
{
new_funcs = malloc(new_capacity * sizeof(atexit_func_entry_t));
if (new_funcs == nullptr)
goto __cxa_atexit_error;
memcpy(new_funcs, s_atexit_funcs, s_atexit_func_count * sizeof(atexit_func_entry_t));
}
else
{
new_funcs = realloc(s_atexit_funcs, new_capacity * sizeof(atexit_func_entry_t));
if (new_funcs == nullptr)
goto __cxa_atexit_error;
}
s_atexit_funcs = reinterpret_cast<atexit_func_entry_t*>(new_funcs);
s_atexit_funcs_capacity = new_capacity;
}
s_atexit_funcs[s_atexit_func_count++] = { s_atexit_funcs[s_atexit_func_count++] = {
.func = func, .func = func,
.arg = arg, .arg = arg,
.dso_handle = dso_handle, .dso_handle = dso_handle,
}; };
pthread_mutex_unlock(&s_atexit_mutex);
return 0; return 0;
__cxa_atexit_error:
pthread_mutex_unlock(&s_atexit_mutex);
return -1;
}; };
extern "C" void __cxa_finalize(void* dso_handle) extern "C" void __cxa_finalize(void* dso_handle)