| /* Creating and controlling threads (native Windows implementation). |
| Copyright (C) 2005-2020 Free Software Foundation, Inc. |
| |
| This program is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program; if not, see <https://www.gnu.org/licenses/>. */ |
| |
| /* Written by Bruno Haible <bruno@clisp.org>, 2005. |
| Based on GCC's gthr-win32.h. */ |
| |
| #include <config.h> |
| |
| /* Specification. */ |
| #include "windows-thread.h" |
| |
| #include <errno.h> |
| #include <process.h> |
| #include <stdlib.h> |
| |
| #include "windows-once.h" |
| #include "windows-tls.h" |
| |
| /* The Thread-Local Storage (TLS) key that allows to access each thread's |
| 'struct glwthread_thread_struct *' pointer. */ |
| static DWORD self_key = (DWORD)-1; |
| |
| /* Initializes self_key. This function must only be called once. */ |
| static void |
| do_init_self_key (void) |
| { |
| self_key = TlsAlloc (); |
| /* If this fails, we're hosed. */ |
| if (self_key == (DWORD)-1) |
| abort (); |
| } |
| |
| /* Initializes self_key. */ |
| static void |
| init_self_key (void) |
| { |
| static glwthread_once_t once = GLWTHREAD_ONCE_INIT; |
| glwthread_once (&once, do_init_self_key); |
| } |
| |
| /* This structure contains information about a thread. |
| It is stored in TLS under key self_key. */ |
| struct glwthread_thread_struct |
| { |
| /* Fields for managing the handle. */ |
| HANDLE volatile handle; |
| CRITICAL_SECTION handle_lock; |
| /* Fields for managing the exit value. */ |
| BOOL volatile detached; |
| void * volatile result; |
| /* Fields for managing the thread start. */ |
| void * (*func) (void *); |
| void *arg; |
| }; |
| |
| /* Return a real HANDLE object for the current thread. */ |
| static HANDLE |
| get_current_thread_handle (void) |
| { |
| HANDLE this_handle; |
| |
| /* GetCurrentThread() returns a pseudo-handle, i.e. only a symbolic |
| identifier, not a real handle. */ |
| if (!DuplicateHandle (GetCurrentProcess (), GetCurrentThread (), |
| GetCurrentProcess (), &this_handle, |
| 0, FALSE, DUPLICATE_SAME_ACCESS)) |
| abort (); |
| return this_handle; |
| } |
| |
| glwthread_thread_t |
| glwthread_thread_self (void) |
| { |
| glwthread_thread_t thread; |
| |
| if (self_key == (DWORD)-1) |
| init_self_key (); |
| thread = TlsGetValue (self_key); |
| if (thread == NULL) |
| { |
| /* This happens only in threads that have not been created through |
| glthread_create(), such as the main thread. */ |
| for (;;) |
| { |
| thread = |
| (struct glwthread_thread_struct *) |
| malloc (sizeof (struct glwthread_thread_struct)); |
| if (thread != NULL) |
| break; |
| /* Memory allocation failed. There is not much we can do. Have to |
| busy-loop, waiting for the availability of memory. */ |
| Sleep (1); |
| } |
| |
| thread->handle = get_current_thread_handle (); |
| InitializeCriticalSection (&thread->handle_lock); |
| thread->detached = FALSE; /* This can lead to a memory leak. */ |
| thread->result = NULL; /* just to be deterministic */ |
| TlsSetValue (self_key, thread); |
| } |
| return thread; |
| } |
| |
| /* The main function of a freshly creating thread. It's a wrapper around |
| the FUNC and ARG arguments passed to glthread_create_func. */ |
| static unsigned int WINAPI |
| wrapper_func (void *varg) |
| { |
| struct glwthread_thread_struct *thread = |
| (struct glwthread_thread_struct *) varg; |
| |
| EnterCriticalSection (&thread->handle_lock); |
| /* Create a new handle for the thread only if the parent thread did not yet |
| fill in the handle. */ |
| if (thread->handle == NULL) |
| thread->handle = get_current_thread_handle (); |
| LeaveCriticalSection (&thread->handle_lock); |
| |
| if (self_key == (DWORD)-1) |
| init_self_key (); |
| TlsSetValue (self_key, thread); |
| |
| /* Run the thread. Store the exit value if the thread was not terminated |
| otherwise. */ |
| thread->result = thread->func (thread->arg); |
| |
| /* Process the TLS destructors. */ |
| glwthread_tls_process_destructors (); |
| |
| if (thread->detached) |
| { |
| /* Clean up the thread, like thrd_join would do. */ |
| DeleteCriticalSection (&thread->handle_lock); |
| CloseHandle (thread->handle); |
| free (thread); |
| } |
| |
| return 0; |
| } |
| |
| int |
| glwthread_thread_create (glwthread_thread_t *threadp, unsigned int attr, |
| void * (*func) (void *), void *arg) |
| { |
| struct glwthread_thread_struct *thread = |
| (struct glwthread_thread_struct *) |
| malloc (sizeof (struct glwthread_thread_struct)); |
| if (thread == NULL) |
| return ENOMEM; |
| thread->handle = NULL; |
| InitializeCriticalSection (&thread->handle_lock); |
| thread->detached = (attr & GLWTHREAD_ATTR_DETACHED ? TRUE : FALSE); |
| thread->result = NULL; /* just to be deterministic */ |
| thread->func = func; |
| thread->arg = arg; |
| |
| { |
| unsigned int thread_id; |
| HANDLE thread_handle; |
| |
| thread_handle = (HANDLE) |
| _beginthreadex (NULL, 100000, wrapper_func, thread, 0, &thread_id); |
| /* calls CreateThread with the same arguments */ |
| if (thread_handle == NULL) |
| { |
| DeleteCriticalSection (&thread->handle_lock); |
| free (thread); |
| return EAGAIN; |
| } |
| |
| EnterCriticalSection (&thread->handle_lock); |
| if (thread->handle == NULL) |
| thread->handle = thread_handle; |
| else |
| /* thread->handle was already set by the thread itself. */ |
| CloseHandle (thread_handle); |
| LeaveCriticalSection (&thread->handle_lock); |
| |
| *threadp = thread; |
| return 0; |
| } |
| } |
| |
| int |
| glwthread_thread_join (glwthread_thread_t thread, void **retvalp) |
| { |
| if (thread == NULL) |
| return EINVAL; |
| |
| if (thread == glwthread_thread_self ()) |
| return EDEADLK; |
| |
| if (thread->detached) |
| return EINVAL; |
| |
| if (WaitForSingleObject (thread->handle, INFINITE) == WAIT_FAILED) |
| return EINVAL; |
| |
| if (retvalp != NULL) |
| *retvalp = thread->result; |
| |
| DeleteCriticalSection (&thread->handle_lock); |
| CloseHandle (thread->handle); |
| free (thread); |
| |
| return 0; |
| } |
| |
| int |
| glwthread_thread_detach (glwthread_thread_t thread) |
| { |
| if (thread == NULL) |
| return EINVAL; |
| |
| if (thread->detached) |
| return EINVAL; |
| |
| thread->detached = TRUE; |
| return 0; |
| } |
| |
| int |
| glwthread_thread_exit (void *retval) |
| { |
| glwthread_thread_t thread = glwthread_thread_self (); |
| thread->result = retval; |
| glwthread_tls_process_destructors (); |
| _endthreadex (0); /* calls ExitThread (0) */ |
| abort (); |
| } |