3
This is intended to be usable independently from Python.
4
The implementation for system foobar is in a file thread_foobar.h
5
which is included by this file dependent on config settings.
6
Stuff shared by all thread_*.h files is collected here. */
10
#ifndef _POSIX_THREADS
11
/* This means pthreads are not implemented in libc headers, hence the macro
12
not present in unistd.h. But they still can be implemented as an external
13
library (e.g. gnu pth in pthread emulation) */
14
# ifdef HAVE_PTHREAD_H
15
# include <pthread.h> /* _POSIX_THREADS */
19
#ifndef DONT_HAVE_STDIO_H
27
#ifndef _POSIX_THREADS
29
/* Check if we're running on HP-UX and _SC_THREADS is defined. If so, then
30
enough of the Posix threads package is implemented to support python
33
This is valid for HP-UX 11.23 running on an ia64 system. If needed, add
34
a check of __ia64 to verify that we're running on a ia64 system instead
39
#define _POSIX_THREADS
43
#endif /* _POSIX_THREADS */
47
static int thread_debug = 0;
48
#define dprintf(args) (void)((thread_debug & 1) && printf args)
49
#define d2printf(args) ((thread_debug & 8) && printf args)
52
#define d2printf(args)
55
static int initialized;
57
static void PyThread__init_thread(void); /* Forward */
60
PyThread_init_thread(void)
63
char *p = Py_GETENV("PYTHONTHREADDEBUG");
67
thread_debug = atoi(p);
75
dprintf(("PyThread_init_thread called\n"));
76
PyThread__init_thread();
79
/* Support for runtime thread stack size tuning.
80
A value of 0 means using the platform's default stack size
81
or the size specified by the THREAD_STACK_SIZE macro. */
82
static size_t _pythread_stacksize = 0;
85
#define PYTHREAD_NAME "pthread"
86
#include "thread_pthread.h"
90
#define PYTHREAD_NAME "nt"
91
#include "thread_nt.h"
97
#include "thread_foobar.h"
101
/* return the current thread stack size */
103
PyThread_get_stacksize(void)
105
return _pythread_stacksize;
108
/* Only platforms defining a THREAD_SET_STACKSIZE() macro
109
in thread_<platform>.h support changing the stack size.
110
Return 0 if stack size is valid,
111
-1 if stack size value is invalid,
112
-2 if setting stack size is not supported. */
114
PyThread_set_stacksize(size_t size)
116
#if defined(THREAD_SET_STACKSIZE)
117
return THREAD_SET_STACKSIZE(size);
123
#ifndef Py_HAVE_NATIVE_TLS
124
/* If the platform has not supplied a platform specific
125
TLS implementation, provide our own.
127
This code stolen from "thread_sgi.h", where it was the only
128
implementation of an existing Python TLS API.
130
/* ------------------------------------------------------------------------
131
Per-thread data ("key") support.
133
Use PyThread_create_key() to create a new key. This is typically shared
136
Use PyThread_set_key_value(thekey, value) to associate void* value with
137
thekey in the current thread. Each thread has a distinct mapping of thekey
138
to a void* value. Caution: if the current thread already has a mapping
139
for thekey, value is ignored.
141
Use PyThread_get_key_value(thekey) to retrieve the void* value associated
142
with thekey in the current thread. This returns NULL if no value is
143
associated with thekey in the current thread.
145
Use PyThread_delete_key_value(thekey) to forget the current thread's associated
146
value for thekey. PyThread_delete_key(thekey) forgets the values associated
147
with thekey across *all* threads.
149
While some of these functions have error-return values, none set any
152
None of the functions does memory management on behalf of the void* values.
153
You need to allocate and deallocate them yourself. If the void* values
154
happen to be PyObject*, these functions don't do refcount operations on
157
The GIL does not need to be held when calling these functions; they supply
158
their own locking. This isn't true of PyThread_create_key(), though (see
161
There's a hidden assumption that PyThread_create_key() will be called before
162
any of the other functions are called. There's also a hidden assumption
163
that calls to PyThread_create_key() are serialized externally.
164
------------------------------------------------------------------------ */
166
/* A singly-linked list of struct key objects remembers all the key->value
167
* associations. File static keyhead heads the list. keymutex is used
168
* to enforce exclusion internally.
171
/* Next record in the list, or NULL if this is the last record. */
174
/* The thread id, according to PyThread_get_thread_ident(). */
177
/* The key and its associated value. */
182
static struct key *keyhead = NULL;
183
static PyThread_type_lock keymutex = NULL;
184
static int nkeys = 0; /* PyThread_create_key() hands out nkeys+1 next */
187
* If the current thread has a mapping for key, the appropriate struct key*
188
* is returned. NB: value is ignored in this case!
189
* If there is no mapping for key in the current thread, then:
190
* If value is NULL, NULL is returned.
191
* Else a mapping of key to value is created for the current thread,
192
* and a pointer to a new struct key* is returned; except that if
193
* malloc() can't find room for a new struct key*, NULL is returned.
194
* So when value==NULL, this acts like a pure lookup routine, and when
195
* value!=NULL, this acts like dict.setdefault(), returning an existing
196
* mapping if one exists, else creating a new mapping.
198
* Caution: this used to be too clever, trying to hold keymutex only
199
* around the "p->next = keyhead; keyhead = p" pair. That allowed
200
* another thread to mutate the list, via key deletion, concurrent with
201
* find_key() crawling over the list. Hilarity ensued. For example, when
202
* the for-loop here does "p = p->next", p could end up pointing at a
203
* record that PyThread_delete_key_value() was concurrently free()'ing.
204
* That could lead to anything, from failing to find a key that exists, to
205
* segfaults. Now we lock the whole routine.
208
find_key(int key, void *value)
210
struct key *p, *prev_p;
211
long id = PyThread_get_thread_ident();
215
PyThread_acquire_lock(keymutex, 1);
217
for (p = keyhead; p != NULL; p = p->next) {
218
if (p->id == id && p->key == key)
220
/* Sanity check. These states should never happen but if
221
* they do we must abort. Otherwise we'll end up spinning in
222
* in a tight loop with the lock held. A similar check is done
223
* in pystate.c tstate_delete_common(). */
225
Py_FatalError("tls find_key: small circular list(!)");
227
if (p->next == keyhead)
228
Py_FatalError("tls find_key: circular list(!)");
234
p = (struct key *)PyMem_RawMalloc(sizeof(struct key));
243
PyThread_release_lock(keymutex);
247
/* Return a new key. This must be called before any other functions in
248
* this family, and callers must arrange to serialize calls to this
249
* function. No violations are detected.
252
PyThread_create_key(void)
254
/* All parts of this function are wrong if it's called by multiple
255
* threads simultaneously.
257
if (keymutex == NULL)
258
keymutex = PyThread_allocate_lock();
262
/* Forget the associations for key across *all* threads. */
264
PyThread_delete_key(int key)
268
PyThread_acquire_lock(keymutex, 1);
270
while ((p = *q) != NULL) {
273
PyMem_RawFree((void *)p);
274
/* NB This does *not* free p->value! */
279
PyThread_release_lock(keymutex);
282
/* Confusing: If the current thread has an association for key,
283
* value is ignored, and 0 is returned. Else an attempt is made to create
284
* an association of key to value for the current thread. 0 is returned
285
* if that succeeds, but -1 is returned if there's not enough memory
286
* to create the association. value must not be NULL.
289
PyThread_set_key_value(int key, void *value)
293
assert(value != NULL);
294
p = find_key(key, value);
301
/* Retrieve the value associated with key in the current thread, or NULL
302
* if the current thread doesn't have an association for key.
305
PyThread_get_key_value(int key)
307
struct key *p = find_key(key, NULL);
315
/* Forget the current thread's association for key, if any. */
317
PyThread_delete_key_value(int key)
319
long id = PyThread_get_thread_ident();
322
PyThread_acquire_lock(keymutex, 1);
324
while ((p = *q) != NULL) {
325
if (p->key == key && p->id == id) {
327
PyMem_RawFree((void *)p);
328
/* NB This does *not* free p->value! */
334
PyThread_release_lock(keymutex);
337
/* Forget everything not associated with the current thread id.
338
* This function is called from PyOS_AfterFork(). It is necessary
339
* because other thread ids which were in use at the time of the fork
340
* may be reused for new threads created in the forked process.
343
PyThread_ReInitTLS(void)
345
long id = PyThread_get_thread_ident();
351
/* As with interpreter_lock in PyEval_ReInitThreads()
352
we just create a new lock without freeing the old one */
353
keymutex = PyThread_allocate_lock();
355
/* Delete all keys which do not match the current thread id */
357
while ((p = *q) != NULL) {
360
PyMem_RawFree((void *)p);
361
/* NB This does *not* free p->value! */
368
#endif /* Py_HAVE_NATIVE_TLS */
370
PyDoc_STRVAR(threadinfo__doc__,
373
A struct sequence holding information about the thread implementation.");
375
static PyStructSequence_Field threadinfo_fields[] = {
376
{"name", "name of the thread implementation"},
377
{"lock", "name of the lock implementation"},
378
{"version", "name and version of the thread library"},
382
static PyStructSequence_Desc threadinfo_desc = {
383
"sys.thread_info", /* name */
384
threadinfo__doc__, /* doc */
385
threadinfo_fields, /* fields */
389
static PyTypeObject ThreadInfoType;
392
PyThread_GetInfo(void)
394
PyObject *threadinfo, *value;
396
#if (defined(_POSIX_THREADS) && defined(HAVE_CONFSTR) \
397
&& defined(_CS_GNU_LIBPTHREAD_VERSION))
402
if (ThreadInfoType.tp_name == 0) {
403
if (PyStructSequence_InitType2(&ThreadInfoType, &threadinfo_desc) < 0)
407
threadinfo = PyStructSequence_New(&ThreadInfoType);
408
if (threadinfo == NULL)
411
value = PyUnicode_FromString(PYTHREAD_NAME);
413
Py_DECREF(threadinfo);
416
PyStructSequence_SET_ITEM(threadinfo, pos++, value);
418
#ifdef _POSIX_THREADS
419
#ifdef USE_SEMAPHORES
420
value = PyUnicode_FromString("semaphore");
422
value = PyUnicode_FromString("mutex+cond");
425
Py_DECREF(threadinfo);
432
PyStructSequence_SET_ITEM(threadinfo, pos++, value);
434
#if (defined(_POSIX_THREADS) && defined(HAVE_CONFSTR) \
435
&& defined(_CS_GNU_LIBPTHREAD_VERSION))
437
len = confstr(_CS_GNU_LIBPTHREAD_VERSION, buffer, sizeof(buffer));
438
if (1 < len && len < sizeof(buffer)) {
439
value = PyUnicode_DecodeFSDefaultAndSize(buffer, len-1);
449
PyStructSequence_SET_ITEM(threadinfo, pos++, value);