| |
| /* Thread package. |
| This is intended to be usable independently from Python. |
| The implementation for system foobar is in a file thread_foobar.h |
| which is included by this file dependent on config settings. |
| Stuff shared by all thread_*.h files is collected here. */ |
| |
| #include "Python.h" |
| |
| |
| #ifndef _POSIX_THREADS |
| /* This means pthreads are not implemented in libc headers, hence the macro |
| not present in unistd.h. But they still can be implemented as an external |
| library (e.g. gnu pth in pthread emulation) */ |
| # ifdef HAVE_PTHREAD_H |
| # include <pthread.h> /* _POSIX_THREADS */ |
| # endif |
| #endif |
| |
| #ifndef DONT_HAVE_STDIO_H |
| #include <stdio.h> |
| #endif |
| |
| #include <stdlib.h> |
| |
| #ifdef __sgi |
| #ifndef HAVE_PTHREAD_H /* XXX Need to check in configure.in */ |
| #undef _POSIX_THREADS |
| #endif |
| #endif |
| |
| #include "pythread.h" |
| |
| #ifndef _POSIX_THREADS |
| |
| #ifdef __sgi |
| #define SGI_THREADS |
| #endif |
| |
| #ifdef HAVE_THREAD_H |
| #define SOLARIS_THREADS |
| #endif |
| |
| #if defined(sun) && !defined(SOLARIS_THREADS) |
| #define SUN_LWP |
| #endif |
| |
| /* Check if we're running on HP-UX and _SC_THREADS is defined. If so, then |
| enough of the Posix threads package is implimented to support python |
| threads. |
| |
| This is valid for HP-UX 11.23 running on an ia64 system. If needed, add |
| a check of __ia64 to verify that we're running on a ia64 system instead |
| of a pa-risc system. |
| */ |
| #ifdef __hpux |
| #ifdef _SC_THREADS |
| #define _POSIX_THREADS |
| #endif |
| #endif |
| |
| #endif /* _POSIX_THREADS */ |
| |
| |
| #ifdef Py_DEBUG |
| static int thread_debug = 0; |
| #define dprintf(args) (void)((thread_debug & 1) && printf args) |
| #define d2printf(args) ((thread_debug & 8) && printf args) |
| #else |
| #define dprintf(args) |
| #define d2printf(args) |
| #endif |
| |
| static int initialized; |
| |
| static void PyThread__init_thread(void); /* Forward */ |
| |
| void |
| PyThread_init_thread(void) |
| { |
| #ifdef Py_DEBUG |
| char *p = Py_GETENV("PYTHONTHREADDEBUG"); |
| |
| if (p) { |
| if (*p) |
| thread_debug = atoi(p); |
| else |
| thread_debug = 1; |
| } |
| #endif /* Py_DEBUG */ |
| if (initialized) |
| return; |
| initialized = 1; |
| dprintf(("PyThread_init_thread called\n")); |
| PyThread__init_thread(); |
| } |
| |
| /* Support for runtime thread stack size tuning. |
| A value of 0 means using the platform's default stack size |
| or the size specified by the THREAD_STACK_SIZE macro. */ |
| static size_t _pythread_stacksize = 0; |
| |
| #ifdef SGI_THREADS |
| #include "thread_sgi.h" |
| #endif |
| |
| #ifdef SOLARIS_THREADS |
| #include "thread_solaris.h" |
| #endif |
| |
| #ifdef SUN_LWP |
| #include "thread_lwp.h" |
| #endif |
| |
| #ifdef HAVE_PTH |
| #include "thread_pth.h" |
| #undef _POSIX_THREADS |
| #endif |
| |
| #ifdef _POSIX_THREADS |
| #include "thread_pthread.h" |
| #endif |
| |
| #ifdef C_THREADS |
| #include "thread_cthread.h" |
| #endif |
| |
| #ifdef NT_THREADS |
| #include "thread_nt.h" |
| #endif |
| |
| #ifdef OS2_THREADS |
| #include "thread_os2.h" |
| #endif |
| |
| #ifdef BEOS_THREADS |
| #include "thread_beos.h" |
| #endif |
| |
| #ifdef WINCE_THREADS |
| #include "thread_wince.h" |
| #endif |
| |
| #ifdef PLAN9_THREADS |
| #include "thread_plan9.h" |
| #endif |
| |
| #ifdef ATHEOS_THREADS |
| #include "thread_atheos.h" |
| #endif |
| |
| /* |
| #ifdef FOOBAR_THREADS |
| #include "thread_foobar.h" |
| #endif |
| */ |
| |
| /* return the current thread stack size */ |
| size_t |
| PyThread_get_stacksize(void) |
| { |
| return _pythread_stacksize; |
| } |
| |
| /* Only platforms defining a THREAD_SET_STACKSIZE() macro |
| in thread_<platform>.h support changing the stack size. |
| Return 0 if stack size is valid, |
| -1 if stack size value is invalid, |
| -2 if setting stack size is not supported. */ |
| int |
| PyThread_set_stacksize(size_t size) |
| { |
| #if defined(THREAD_SET_STACKSIZE) |
| return THREAD_SET_STACKSIZE(size); |
| #else |
| return -2; |
| #endif |
| } |
| |
| #ifndef Py_HAVE_NATIVE_TLS |
| /* If the platform has not supplied a platform specific |
| TLS implementation, provide our own. |
| |
| This code stolen from "thread_sgi.h", where it was the only |
| implementation of an existing Python TLS API. |
| */ |
| /* ------------------------------------------------------------------------ |
| Per-thread data ("key") support. |
| |
| Use PyThread_create_key() to create a new key. This is typically shared |
| across threads. |
| |
| Use PyThread_set_key_value(thekey, value) to associate void* value with |
| thekey in the current thread. Each thread has a distinct mapping of thekey |
| to a void* value. Caution: if the current thread already has a mapping |
| for thekey, value is ignored. |
| |
| Use PyThread_get_key_value(thekey) to retrieve the void* value associated |
| with thekey in the current thread. This returns NULL if no value is |
| associated with thekey in the current thread. |
| |
| Use PyThread_delete_key_value(thekey) to forget the current thread's associated |
| value for thekey. PyThread_delete_key(thekey) forgets the values associated |
| with thekey across *all* threads. |
| |
| While some of these functions have error-return values, none set any |
| Python exception. |
| |
| None of the functions does memory management on behalf of the void* values. |
| You need to allocate and deallocate them yourself. If the void* values |
| happen to be PyObject*, these functions don't do refcount operations on |
| them either. |
| |
| The GIL does not need to be held when calling these functions; they supply |
| their own locking. This isn't true of PyThread_create_key(), though (see |
| next paragraph). |
| |
| There's a hidden assumption that PyThread_create_key() will be called before |
| any of the other functions are called. There's also a hidden assumption |
| that calls to PyThread_create_key() are serialized externally. |
| ------------------------------------------------------------------------ */ |
| |
| /* A singly-linked list of struct key objects remembers all the key->value |
| * associations. File static keyhead heads the list. keymutex is used |
| * to enforce exclusion internally. |
| */ |
| struct key { |
| /* Next record in the list, or NULL if this is the last record. */ |
| struct key *next; |
| |
| /* The thread id, according to PyThread_get_thread_ident(). */ |
| long id; |
| |
| /* The key and its associated value. */ |
| int key; |
| void *value; |
| }; |
| |
| static struct key *keyhead = NULL; |
| static PyThread_type_lock keymutex = NULL; |
| static int nkeys = 0; /* PyThread_create_key() hands out nkeys+1 next */ |
| |
| /* Internal helper. |
| * If the current thread has a mapping for key, the appropriate struct key* |
| * is returned. NB: value is ignored in this case! |
| * If there is no mapping for key in the current thread, then: |
| * If value is NULL, NULL is returned. |
| * Else a mapping of key to value is created for the current thread, |
| * and a pointer to a new struct key* is returned; except that if |
| * malloc() can't find room for a new struct key*, NULL is returned. |
| * So when value==NULL, this acts like a pure lookup routine, and when |
| * value!=NULL, this acts like dict.setdefault(), returning an existing |
| * mapping if one exists, else creating a new mapping. |
| * |
| * Caution: this used to be too clever, trying to hold keymutex only |
| * around the "p->next = keyhead; keyhead = p" pair. That allowed |
| * another thread to mutate the list, via key deletion, concurrent with |
| * find_key() crawling over the list. Hilarity ensued. For example, when |
| * the for-loop here does "p = p->next", p could end up pointing at a |
| * record that PyThread_delete_key_value() was concurrently free()'ing. |
| * That could lead to anything, from failing to find a key that exists, to |
| * segfaults. Now we lock the whole routine. |
| */ |
| static struct key * |
| find_key(int key, void *value) |
| { |
| struct key *p; |
| long id = PyThread_get_thread_ident(); |
| |
| if (!keymutex) |
| return NULL; |
| PyThread_acquire_lock(keymutex, 1); |
| for (p = keyhead; p != NULL; p = p->next) { |
| if (p->id == id && p->key == key) |
| goto Done; |
| } |
| if (value == NULL) { |
| assert(p == NULL); |
| goto Done; |
| } |
| p = (struct key *)malloc(sizeof(struct key)); |
| if (p != NULL) { |
| p->id = id; |
| p->key = key; |
| p->value = value; |
| p->next = keyhead; |
| keyhead = p; |
| } |
| Done: |
| PyThread_release_lock(keymutex); |
| return p; |
| } |
| |
| /* Return a new key. This must be called before any other functions in |
| * this family, and callers must arrange to serialize calls to this |
| * function. No violations are detected. |
| */ |
| int |
| PyThread_create_key(void) |
| { |
| /* All parts of this function are wrong if it's called by multiple |
| * threads simultaneously. |
| */ |
| if (keymutex == NULL) |
| keymutex = PyThread_allocate_lock(); |
| return ++nkeys; |
| } |
| |
| /* Forget the associations for key across *all* threads. */ |
| void |
| PyThread_delete_key(int key) |
| { |
| struct key *p, **q; |
| |
| PyThread_acquire_lock(keymutex, 1); |
| q = &keyhead; |
| while ((p = *q) != NULL) { |
| if (p->key == key) { |
| *q = p->next; |
| free((void *)p); |
| /* NB This does *not* free p->value! */ |
| } |
| else |
| q = &p->next; |
| } |
| PyThread_release_lock(keymutex); |
| } |
| |
| /* Confusing: If the current thread has an association for key, |
| * value is ignored, and 0 is returned. Else an attempt is made to create |
| * an association of key to value for the current thread. 0 is returned |
| * if that succeeds, but -1 is returned if there's not enough memory |
| * to create the association. value must not be NULL. |
| */ |
| int |
| PyThread_set_key_value(int key, void *value) |
| { |
| struct key *p; |
| |
| assert(value != NULL); |
| p = find_key(key, value); |
| if (p == NULL) |
| return -1; |
| else |
| return 0; |
| } |
| |
| /* Retrieve the value associated with key in the current thread, or NULL |
| * if the current thread doesn't have an association for key. |
| */ |
| void * |
| PyThread_get_key_value(int key) |
| { |
| struct key *p = find_key(key, NULL); |
| |
| if (p == NULL) |
| return NULL; |
| else |
| return p->value; |
| } |
| |
| /* Forget the current thread's association for key, if any. */ |
| void |
| PyThread_delete_key_value(int key) |
| { |
| long id = PyThread_get_thread_ident(); |
| struct key *p, **q; |
| |
| PyThread_acquire_lock(keymutex, 1); |
| q = &keyhead; |
| while ((p = *q) != NULL) { |
| if (p->key == key && p->id == id) { |
| *q = p->next; |
| free((void *)p); |
| /* NB This does *not* free p->value! */ |
| break; |
| } |
| else |
| q = &p->next; |
| } |
| PyThread_release_lock(keymutex); |
| } |
| |
| /* Forget everything not associated with the current thread id. |
| * This function is called from PyOS_AfterFork(). It is necessary |
| * because other thread ids which were in use at the time of the fork |
| * may be reused for new threads created in the forked process. |
| */ |
| void |
| PyThread_ReInitTLS(void) |
| { |
| long id = PyThread_get_thread_ident(); |
| struct key *p, **q; |
| |
| if (!keymutex) |
| return; |
| |
| /* As with interpreter_lock in PyEval_ReInitThreads() |
| we just create a new lock without freeing the old one */ |
| keymutex = PyThread_allocate_lock(); |
| |
| /* Delete all keys which do not match the current thread id */ |
| q = &keyhead; |
| while ((p = *q) != NULL) { |
| if (p->id != id) { |
| *q = p->next; |
| free((void *)p); |
| /* NB This does *not* free p->value! */ |
| } |
| else |
| q = &p->next; |
| } |
| } |
| |
| #endif /* Py_HAVE_NATIVE_TLS */ |