mirror of
https://github.com/RGBCube/serenity
synced 2025-07-25 14:17:36 +00:00
LibC+LibPthread: Implement function forwarding for libpthread
GCC will insert various calls to pthread functions when compiling C++ code with static initializers, even when the user doesn't link their program against libpthread explicitly. This is used to make static initializers thread-safe, e.g. when building a library that does not itself use thread functionality and thus does not link against libpthread - but is intended to be used with other code that does use libpthread explicitly. This makes these symbols available in libc.
This commit is contained in:
parent
db3fd11646
commit
88cebb05ad
14 changed files with 381 additions and 100 deletions
|
@ -55,8 +55,6 @@ constexpr size_t highest_reasonable_stack_size = 8 * MiB; // That's the default
|
|||
#define __RETURN_PTHREAD_ERROR(rc) \
|
||||
return ((rc) < 0 ? -(rc) : 0)
|
||||
|
||||
extern void (*__libc_pthread_key_destroy_for_current_thread)();
|
||||
|
||||
extern "C" {
|
||||
|
||||
static void* pthread_create_helper(void* (*routine)(void*), void* argument)
|
||||
|
@ -531,99 +529,31 @@ int pthread_cond_broadcast(pthread_cond_t* cond)
|
|||
return 0;
|
||||
}
|
||||
|
||||
static constexpr int max_keys = PTHREAD_KEYS_MAX;
|
||||
|
||||
typedef void (*KeyDestructor)(void*);
|
||||
|
||||
struct KeyTable {
|
||||
KeyDestructor destructors[max_keys] { nullptr };
|
||||
int next { 0 };
|
||||
pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
|
||||
};
|
||||
|
||||
struct SpecificTable {
|
||||
void* values[max_keys] { nullptr };
|
||||
};
|
||||
|
||||
static KeyTable s_keys;
|
||||
|
||||
__thread SpecificTable t_specifics;
|
||||
// libgcc expects this function to exist in libpthread, even
|
||||
// if it is not implemented.
|
||||
int pthread_cancel(pthread_t)
|
||||
{
|
||||
TODO();
|
||||
}
|
||||
|
||||
int pthread_key_create(pthread_key_t* key, KeyDestructor destructor)
|
||||
{
|
||||
int ret = 0;
|
||||
pthread_mutex_lock(&s_keys.mutex);
|
||||
if (s_keys.next >= max_keys) {
|
||||
ret = EAGAIN;
|
||||
} else {
|
||||
*key = s_keys.next++;
|
||||
s_keys.destructors[*key] = destructor;
|
||||
ret = 0;
|
||||
}
|
||||
pthread_mutex_unlock(&s_keys.mutex);
|
||||
return ret;
|
||||
return __pthread_key_create(key, destructor);
|
||||
}
|
||||
|
||||
int pthread_key_delete(pthread_key_t key)
|
||||
{
|
||||
if (key < 0 || key >= max_keys)
|
||||
return EINVAL;
|
||||
pthread_mutex_lock(&s_keys.mutex);
|
||||
s_keys.destructors[key] = nullptr;
|
||||
pthread_mutex_unlock(&s_keys.mutex);
|
||||
return 0;
|
||||
return __pthread_key_delete(key);
|
||||
}
|
||||
|
||||
void* pthread_getspecific(pthread_key_t key)
|
||||
{
|
||||
if (key < 0)
|
||||
return nullptr;
|
||||
if (key >= max_keys)
|
||||
return nullptr;
|
||||
return t_specifics.values[key];
|
||||
return __pthread_getspecific(key);
|
||||
}
|
||||
|
||||
int pthread_setspecific(pthread_key_t key, const void* value)
|
||||
{
|
||||
if (key < 0)
|
||||
return EINVAL;
|
||||
if (key >= max_keys)
|
||||
return EINVAL;
|
||||
|
||||
t_specifics.values[key] = const_cast<void*>(value);
|
||||
return 0;
|
||||
}
|
||||
|
||||
[[gnu::constructor]] static void set_libc_key_destructor()
|
||||
{
|
||||
__libc_pthread_key_destroy_for_current_thread = __pthread_key_destroy_for_current_thread;
|
||||
}
|
||||
|
||||
void __pthread_key_destroy_for_current_thread()
|
||||
{
|
||||
// This function will either be called during exit_thread, for a pthread, or
|
||||
// during global program shutdown for the main thread.
|
||||
|
||||
pthread_mutex_lock(&s_keys.mutex);
|
||||
size_t num_used_keys = s_keys.next;
|
||||
|
||||
// Dr. POSIX accounts for weird key destructors setting their own key again.
|
||||
// Or even, setting other unrelated keys? Odd, but whatever the Doc says goes.
|
||||
|
||||
for (size_t destruct_iteration = 0; destruct_iteration < PTHREAD_DESTRUCTOR_ITERATIONS; ++destruct_iteration) {
|
||||
bool any_nonnull_destructors = false;
|
||||
for (size_t key_index = 0; key_index < num_used_keys; ++key_index) {
|
||||
void* value = exchange(t_specifics.values[key_index], nullptr);
|
||||
|
||||
if (value && s_keys.destructors[key_index]) {
|
||||
any_nonnull_destructors = true;
|
||||
(*s_keys.destructors[key_index])(value);
|
||||
}
|
||||
}
|
||||
if (!any_nonnull_destructors)
|
||||
break;
|
||||
}
|
||||
pthread_mutex_unlock(&s_keys.mutex);
|
||||
return __pthread_setspecific(key, value);
|
||||
}
|
||||
|
||||
int pthread_setname_np(pthread_t thread, const char* name)
|
||||
|
|
Loading…
Add table
Add a link
Reference in a new issue