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| 1 | |||
| 2 | /* Thread package. | ||
| 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. */ | ||
| 7 | |||
| 8 | #include "Python.h" | ||
| 9 | |||
| 10 | |||
| 11 | #ifndef _POSIX_THREADS | ||
| 12 | /* This means pthreads are not implemented in libc headers, hence the macro | ||
| 13 | not present in unistd.h. But they still can be implemented as an external | ||
| 14 | library (e.g. gnu pth in pthread emulation) */ | ||
| 15 | # ifdef HAVE_PTHREAD_H | ||
| 16 | # include <pthread.h> /* _POSIX_THREADS */ | ||
| 17 | # endif | ||
| 18 | #endif | ||
| 19 | |||
| 20 | #ifndef DONT_HAVE_STDIO_H | ||
| 21 | #include <stdio.h> | ||
| 22 | #endif | ||
| 23 | |||
| 24 | #include <stdlib.h> | ||
| 25 | |||
| 26 | #ifdef __sgi | ||
| 27 | #ifndef HAVE_PTHREAD_H /* XXX Need to check in configure.in */ | ||
| 28 | #undef _POSIX_THREADS | ||
| 29 | #endif | ||
| 30 | #endif | ||
| 31 | |||
| 32 | #include "pythread.h" | ||
| 33 | |||
| 34 | #ifndef _POSIX_THREADS | ||
| 35 | |||
| 36 | #ifdef __sgi | ||
| 37 | #define SGI_THREADS | ||
| 38 | #endif | ||
| 39 | |||
| 40 | #ifdef HAVE_THREAD_H | ||
| 41 | #define SOLARIS_THREADS | ||
| 42 | #endif | ||
| 43 | |||
| 44 | #if defined(sun) && !defined(SOLARIS_THREADS) | ||
| 45 | #define SUN_LWP | ||
| 46 | #endif | ||
| 47 | |||
| 48 | /* Check if we're running on HP-UX and _SC_THREADS is defined. If so, then | ||
| 49 | enough of the Posix threads package is implimented to support python | ||
| 50 | threads. | ||
| 51 | |||
| 52 | This is valid for HP-UX 11.23 running on an ia64 system. If needed, add | ||
| 53 | a check of __ia64 to verify that we're running on a ia64 system instead | ||
| 54 | of a pa-risc system. | ||
| 55 | */ | ||
| 56 | #ifdef __hpux | ||
| 57 | #ifdef _SC_THREADS | ||
| 58 | #define _POSIX_THREADS | ||
| 59 | #endif | ||
| 60 | #endif | ||
| 61 | |||
| 62 | #endif /* _POSIX_THREADS */ | ||
| 63 | |||
| 64 | |||
| 65 | #ifdef Py_DEBUG | ||
| 66 | static int thread_debug = 0; | ||
| 67 | #define dprintf(args) (void)((thread_debug & 1) && printf args) | ||
| 68 | #define d2printf(args) ((thread_debug & 8) && printf args) | ||
| 69 | #else | ||
| 70 | #define dprintf(args) | ||
| 71 | #define d2printf(args) | ||
| 72 | #endif | ||
| 73 | |||
| 74 | static int initialized; | ||
| 75 | |||
| 76 | static void PyThread__init_thread(void); /* Forward */ | ||
| 77 | |||
| 78 | void | ||
| 79 | PyThread_init_thread(void) | ||
| 80 | { | ||
| 81 | #ifdef Py_DEBUG | ||
| 82 | char *p = getenv("THREADDEBUG"); | ||
| 83 | |||
| 84 | if (p) { | ||
| 85 | if (*p) | ||
| 86 | thread_debug = atoi(p); | ||
| 87 | else | ||
| 88 | thread_debug = 1; | ||
| 89 | } | ||
| 90 | #endif /* Py_DEBUG */ | ||
| 91 | if (initialized) | ||
| 92 | return; | ||
| 93 | initialized = 1; | ||
| 94 | dprintf(("PyThread_init_thread called\n")); | ||
| 95 | PyThread__init_thread(); | ||
| 96 | } | ||
| 97 | |||
| 98 | /* Support for runtime thread stack size tuning. | ||
| 99 | A value of 0 means using the platform's default stack size | ||
| 100 | or the size specified by the THREAD_STACK_SIZE macro. */ | ||
| 101 | static size_t _pythread_stacksize = 0; | ||
| 102 | |||
| 103 | #ifdef SGI_THREADS | ||
| 104 | #include "thread_sgi.h" | ||
| 105 | #endif | ||
| 106 | |||
| 107 | #ifdef SOLARIS_THREADS | ||
| 108 | #include "thread_solaris.h" | ||
| 109 | #endif | ||
| 110 | |||
| 111 | #ifdef SUN_LWP | ||
| 112 | #include "thread_lwp.h" | ||
| 113 | #endif | ||
| 114 | |||
| 115 | #ifdef HAVE_PTH | ||
| 116 | #include "thread_pth.h" | ||
| 117 | #undef _POSIX_THREADS | ||
| 118 | #endif | ||
| 119 | |||
| 120 | #ifdef _POSIX_THREADS | ||
| 121 | #include "thread_pthread.h" | ||
| 122 | #endif | ||
| 123 | |||
| 124 | #ifdef C_THREADS | ||
| 125 | #include "thread_cthread.h" | ||
| 126 | #endif | ||
| 127 | |||
| 128 | #ifdef NT_THREADS | ||
| 129 | #include "thread_nt.h" | ||
| 130 | #endif | ||
| 131 | |||
| 132 | #ifdef OS2_THREADS | ||
| 133 | #include "thread_os2.h" | ||
| 134 | #endif | ||
| 135 | |||
| 136 | #ifdef BEOS_THREADS | ||
| 137 | #include "thread_beos.h" | ||
| 138 | #endif | ||
| 139 | |||
| 140 | #ifdef WINCE_THREADS | ||
| 141 | #include "thread_wince.h" | ||
| 142 | #endif | ||
| 143 | |||
| 144 | #ifdef PLAN9_THREADS | ||
| 145 | #include "thread_plan9.h" | ||
| 146 | #endif | ||
| 147 | |||
| 148 | #ifdef ATHEOS_THREADS | ||
| 149 | #include "thread_atheos.h" | ||
| 150 | #endif | ||
| 151 | |||
| 152 | /* | ||
| 153 | #ifdef FOOBAR_THREADS | ||
| 154 | #include "thread_foobar.h" | ||
| 155 | #endif | ||
| 156 | */ | ||
| 157 | |||
| 158 | /* return the current thread stack size */ | ||
| 159 | size_t | ||
| 160 | PyThread_get_stacksize(void) | ||
| 161 | { | ||
| 162 | return _pythread_stacksize; | ||
| 163 | } | ||
| 164 | |||
| 165 | /* Only platforms defining a THREAD_SET_STACKSIZE() macro | ||
| 166 | in thread_<platform>.h support changing the stack size. | ||
| 167 | Return 0 if stack size is valid, | ||
| 168 | -1 if stack size value is invalid, | ||
| 169 | -2 if setting stack size is not supported. */ | ||
| 170 | int | ||
| 171 | PyThread_set_stacksize(size_t size) | ||
| 172 | { | ||
| 173 | #if defined(THREAD_SET_STACKSIZE) | ||
| 174 | return THREAD_SET_STACKSIZE(size); | ||
| 175 | #else | ||
| 176 | return -2; | ||
| 177 | #endif | ||
| 178 | } | ||
| 179 | |||
| 180 | #ifndef Py_HAVE_NATIVE_TLS | ||
| 181 | /* If the platform has not supplied a platform specific | ||
| 182 | TLS implementation, provide our own. | ||
| 183 | |||
| 184 | This code stolen from "thread_sgi.h", where it was the only | ||
| 185 | implementation of an existing Python TLS API. | ||
| 186 | */ | ||
| 187 | /* ------------------------------------------------------------------------ | ||
| 188 | Per-thread data ("key") support. | ||
| 189 | |||
| 190 | Use PyThread_create_key() to create a new key. This is typically shared | ||
| 191 | across threads. | ||
| 192 | |||
| 193 | Use PyThread_set_key_value(thekey, value) to associate void* value with | ||
| 194 | thekey in the current thread. Each thread has a distinct mapping of thekey | ||
| 195 | to a void* value. Caution: if the current thread already has a mapping | ||
| 196 | for thekey, value is ignored. | ||
| 197 | |||
| 198 | Use PyThread_get_key_value(thekey) to retrieve the void* value associated | ||
| 199 | with thekey in the current thread. This returns NULL if no value is | ||
| 200 | associated with thekey in the current thread. | ||
| 201 | |||
| 202 | Use PyThread_delete_key_value(thekey) to forget the current thread's associated | ||
| 203 | value for thekey. PyThread_delete_key(thekey) forgets the values associated | ||
| 204 | with thekey across *all* threads. | ||
| 205 | |||
| 206 | While some of these functions have error-return values, none set any | ||
| 207 | Python exception. | ||
| 208 | |||
| 209 | None of the functions does memory management on behalf of the void* values. | ||
| 210 | You need to allocate and deallocate them yourself. If the void* values | ||
| 211 | happen to be PyObject*, these functions don't do refcount operations on | ||
| 212 | them either. | ||
| 213 | |||
| 214 | The GIL does not need to be held when calling these functions; they supply | ||
| 215 | their own locking. This isn't true of PyThread_create_key(), though (see | ||
| 216 | next paragraph). | ||
| 217 | |||
| 218 | There's a hidden assumption that PyThread_create_key() will be called before | ||
| 219 | any of the other functions are called. There's also a hidden assumption | ||
| 220 | that calls to PyThread_create_key() are serialized externally. | ||
| 221 | ------------------------------------------------------------------------ */ | ||
| 222 | |||
| 223 | /* A singly-linked list of struct key objects remembers all the key->value | ||
| 224 | * associations. File static keyhead heads the list. keymutex is used | ||
| 225 | * to enforce exclusion internally. | ||
| 226 | */ | ||
| 227 | struct key { | ||
| 228 | /* Next record in the list, or NULL if this is the last record. */ | ||
| 229 | struct key *next; | ||
| 230 | |||
| 231 | /* The thread id, according to PyThread_get_thread_ident(). */ | ||
| 232 | long id; | ||
| 233 | |||
| 234 | /* The key and its associated value. */ | ||
| 235 | int key; | ||
| 236 | void *value; | ||
| 237 | }; | ||
| 238 | |||
| 239 | static struct key *keyhead = NULL; | ||
| 240 | static PyThread_type_lock keymutex = NULL; | ||
| 241 | static int nkeys = 0; /* PyThread_create_key() hands out nkeys+1 next */ | ||
| 242 | |||
| 243 | /* Internal helper. | ||
| 244 | * If the current thread has a mapping for key, the appropriate struct key* | ||
| 245 | * is returned. NB: value is ignored in this case! | ||
| 246 | * If there is no mapping for key in the current thread, then: | ||
| 247 | * If value is NULL, NULL is returned. | ||
| 248 | * Else a mapping of key to value is created for the current thread, | ||
| 249 | * and a pointer to a new struct key* is returned; except that if | ||
| 250 | * malloc() can't find room for a new struct key*, NULL is returned. | ||
| 251 | * So when value==NULL, this acts like a pure lookup routine, and when | ||
| 252 | * value!=NULL, this acts like dict.setdefault(), returning an existing | ||
| 253 | * mapping if one exists, else creating a new mapping. | ||
| 254 | * | ||
| 255 | * Caution: this used to be too clever, trying to hold keymutex only | ||
| 256 | * around the "p->next = keyhead; keyhead = p" pair. That allowed | ||
| 257 | * another thread to mutate the list, via key deletion, concurrent with | ||
| 258 | * find_key() crawling over the list. Hilarity ensued. For example, when | ||
| 259 | * the for-loop here does "p = p->next", p could end up pointing at a | ||
| 260 | * record that PyThread_delete_key_value() was concurrently free()'ing. | ||
| 261 | * That could lead to anything, from failing to find a key that exists, to | ||
| 262 | * segfaults. Now we lock the whole routine. | ||
| 263 | */ | ||
| 264 | static struct key * | ||
| 265 | find_key(int key, void *value) | ||
| 266 | { | ||
| 267 | struct key *p; | ||
| 268 | long id = PyThread_get_thread_ident(); | ||
| 269 | |||
| 270 | if (!keymutex) | ||
| 271 | return NULL; | ||
| 272 | PyThread_acquire_lock(keymutex, 1); | ||
| 273 | for (p = keyhead; p != NULL; p = p->next) { | ||
| 274 | if (p->id == id && p->key == key) | ||
| 275 | goto Done; | ||
| 276 | } | ||
| 277 | if (value == NULL) { | ||
| 278 | assert(p == NULL); | ||
| 279 | goto Done; | ||
| 280 | } | ||
| 281 | p = (struct key *)malloc(sizeof(struct key)); | ||
| 282 | if (p != NULL) { | ||
| 283 | p->id = id; | ||
| 284 | p->key = key; | ||
| 285 | p->value = value; | ||
| 286 | p->next = keyhead; | ||
| 287 | keyhead = p; | ||
| 288 | } | ||
| 289 | Done: | ||
| 290 | PyThread_release_lock(keymutex); | ||
| 291 | return p; | ||
| 292 | } | ||
| 293 | |||
| 294 | /* Return a new key. This must be called before any other functions in | ||
| 295 | * this family, and callers must arrange to serialize calls to this | ||
| 296 | * function. No violations are detected. | ||
| 297 | */ | ||
| 298 | int | ||
| 299 | PyThread_create_key(void) | ||
| 300 | { | ||
| 301 | /* All parts of this function are wrong if it's called by multiple | ||
| 302 | * threads simultaneously. | ||
| 303 | */ | ||
| 304 | if (keymutex == NULL) | ||
| 305 | keymutex = PyThread_allocate_lock(); | ||
| 306 | return ++nkeys; | ||
| 307 | } | ||
| 308 | |||
| 309 | /* Forget the associations for key across *all* threads. */ | ||
| 310 | void | ||
| 311 | PyThread_delete_key(int key) | ||
| 312 | { | ||
| 313 | struct key *p, **q; | ||
| 314 | |||
| 315 | PyThread_acquire_lock(keymutex, 1); | ||
| 316 | q = &keyhead; | ||
| 317 | while ((p = *q) != NULL) { | ||
| 318 | if (p->key == key) { | ||
| 319 | *q = p->next; | ||
| 320 | free((void *)p); | ||
| 321 | /* NB This does *not* free p->value! */ | ||
| 322 | } | ||
| 323 | else | ||
| 324 | q = &p->next; | ||
| 325 | } | ||
| 326 | PyThread_release_lock(keymutex); | ||
| 327 | } | ||
| 328 | |||
| 329 | /* Confusing: If the current thread has an association for key, | ||
| 330 | * value is ignored, and 0 is returned. Else an attempt is made to create | ||
| 331 | * an association of key to value for the current thread. 0 is returned | ||
| 332 | * if that succeeds, but -1 is returned if there's not enough memory | ||
| 333 | * to create the association. value must not be NULL. | ||
| 334 | */ | ||
| 335 | int | ||
| 336 | PyThread_set_key_value(int key, void *value) | ||
| 337 | { | ||
| 338 | struct key *p; | ||
| 339 | |||
| 340 | assert(value != NULL); | ||
| 341 | p = find_key(key, value); | ||
| 342 | if (p == NULL) | ||
| 343 | return -1; | ||
| 344 | else | ||
| 345 | return 0; | ||
| 346 | } | ||
| 347 | |||
| 348 | /* Retrieve the value associated with key in the current thread, or NULL | ||
| 349 | * if the current thread doesn't have an association for key. | ||
| 350 | */ | ||
| 351 | void * | ||
| 352 | PyThread_get_key_value(int key) | ||
| 353 | { | ||
| 354 | struct key *p = find_key(key, NULL); | ||
| 355 | |||
| 356 | if (p == NULL) | ||
| 357 | return NULL; | ||
| 358 | else | ||
| 359 | return p->value; | ||
| 360 | } | ||
| 361 | |||
| 362 | /* Forget the current thread's association for key, if any. */ | ||
| 363 | void | ||
| 364 | PyThread_delete_key_value(int key) | ||
| 365 | { | ||
| 366 | long id = PyThread_get_thread_ident(); | ||
| 367 | struct key *p, **q; | ||
| 368 | |||
| 369 | PyThread_acquire_lock(keymutex, 1); | ||
| 370 | q = &keyhead; | ||
| 371 | while ((p = *q) != NULL) { | ||
| 372 | if (p->key == key && p->id == id) { | ||
| 373 | *q = p->next; | ||
| 374 | free((void *)p); | ||
| 375 | /* NB This does *not* free p->value! */ | ||
| 376 | break; | ||
| 377 | } | ||
| 378 | else | ||
| 379 | q = &p->next; | ||
| 380 | } | ||
| 381 | PyThread_release_lock(keymutex); | ||
| 382 | } | ||
| 383 | |||
| 384 | #endif /* Py_HAVE_NATIVE_TLS */ | ||