mirror of
https://github.com/python/cpython
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214 lines
5.2 KiB
C
214 lines
5.2 KiB
C
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/* GNU pth threads interface
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http://www.gnu.org/software/pth
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2000-05-03 Andy Dustman <andy@dustman.net>
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Adapted from Posix threads interface
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12 May 1997 -- david arnold <davida@pobox.com>
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*/
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#include <stdlib.h>
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#include <string.h>
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#include <pth.h>
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/* A pth mutex isn't sufficient to model the Python lock type
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* because pth mutexes can be acquired multiple times by the
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* same thread.
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*
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* The pth_lock struct implements a Python lock as a "locked?" bit
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* and a <condition, mutex> pair. In general, if the bit can be acquired
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* instantly, it is, else the pair is used to block the thread until the
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* bit is cleared.
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*/
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typedef struct {
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char locked; /* 0=unlocked, 1=locked */
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/* a <cond, mutex> pair to handle an acquire of a locked lock */
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pth_cond_t lock_released;
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pth_mutex_t mut;
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} pth_lock;
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#define CHECK_STATUS(name) if (status == -1) { printf("%d ", status); perror(name); error = 1; }
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pth_attr_t PyThread_attr;
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/*
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* Initialization.
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*/
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static void PyThread__init_thread(void)
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{
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pth_init();
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PyThread_attr = pth_attr_new();
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pth_attr_set(PyThread_attr, PTH_ATTR_STACK_SIZE, 1<<18);
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pth_attr_set(PyThread_attr, PTH_ATTR_JOINABLE, FALSE);
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}
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/*
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* Thread support.
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*/
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long PyThread_start_new_thread(void (*func)(void *), void *arg)
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{
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pth_t th;
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dprintf(("PyThread_start_new_thread called\n"));
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if (!initialized)
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PyThread_init_thread();
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th = pth_spawn(PyThread_attr,
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(void* (*)(void *))func,
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(void *)arg
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);
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return th;
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}
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long PyThread_get_thread_ident(void)
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{
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volatile pth_t threadid;
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if (!initialized)
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PyThread_init_thread();
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/* Jump through some hoops for Alpha OSF/1 */
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threadid = pth_self();
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return (long) *(long *) &threadid;
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}
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static void do_PyThread_exit_thread(int no_cleanup)
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{
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dprintf(("PyThread_exit_thread called\n"));
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if (!initialized) {
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if (no_cleanup)
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_exit(0);
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else
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exit(0);
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}
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}
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void PyThread_exit_thread(void)
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{
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do_PyThread_exit_thread(0);
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}
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void PyThread__exit_thread(void)
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{
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do_PyThread_exit_thread(1);
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}
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#ifndef NO_EXIT_PROG
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static void do_PyThread_exit_prog(int status, int no_cleanup)
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{
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dprintf(("PyThread_exit_prog(%d) called\n", status));
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if (!initialized)
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if (no_cleanup)
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_exit(status);
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else
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exit(status);
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}
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void PyThread_exit_prog(int status)
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{
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do_PyThread_exit_prog(status, 0);
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}
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void PyThread__exit_prog(int status)
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{
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do_PyThread_exit_prog(status, 1);
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}
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#endif /* NO_EXIT_PROG */
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/*
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* Lock support.
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*/
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PyThread_type_lock PyThread_allocate_lock(void)
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{
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pth_lock *lock;
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int status, error = 0;
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dprintf(("PyThread_allocate_lock called\n"));
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if (!initialized)
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PyThread_init_thread();
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lock = (pth_lock *) malloc(sizeof(pth_lock));
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memset((void *)lock, '\0', sizeof(pth_lock));
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if (lock) {
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lock->locked = 0;
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status = pth_mutex_init(&lock->mut);
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CHECK_STATUS("pth_mutex_init");
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status = pth_cond_init(&lock->lock_released);
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CHECK_STATUS("pth_cond_init");
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if (error) {
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free((void *)lock);
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lock = NULL;
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}
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}
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dprintf(("PyThread_allocate_lock() -> %p\n", lock));
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return (PyThread_type_lock) lock;
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}
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void PyThread_free_lock(PyThread_type_lock lock)
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{
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pth_lock *thelock = (pth_lock *)lock;
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dprintf(("PyThread_free_lock(%p) called\n", lock));
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free((void *)thelock);
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}
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int PyThread_acquire_lock(PyThread_type_lock lock, int waitflag)
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{
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int success;
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pth_lock *thelock = (pth_lock *)lock;
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int status, error = 0;
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dprintf(("PyThread_acquire_lock(%p, %d) called\n", lock, waitflag));
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status = pth_mutex_acquire(&thelock->mut, !waitflag, NULL);
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CHECK_STATUS("pth_mutex_acquire[1]");
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success = thelock->locked == 0;
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if (success) thelock->locked = 1;
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status = pth_mutex_release( &thelock->mut );
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CHECK_STATUS("pth_mutex_release[1]");
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if ( !success && waitflag ) {
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/* continue trying until we get the lock */
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/* mut must be locked by me -- part of the condition
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* protocol */
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status = pth_mutex_acquire( &thelock->mut, !waitflag, NULL );
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CHECK_STATUS("pth_mutex_acquire[2]");
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while ( thelock->locked ) {
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status = pth_cond_await(&thelock->lock_released,
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&thelock->mut, NULL);
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CHECK_STATUS("pth_cond_await");
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}
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thelock->locked = 1;
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status = pth_mutex_release( &thelock->mut );
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CHECK_STATUS("pth_mutex_release[2]");
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success = 1;
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}
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if (error) success = 0;
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dprintf(("PyThread_acquire_lock(%p, %d) -> %d\n", lock, waitflag, success));
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return success;
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}
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void PyThread_release_lock(PyThread_type_lock lock)
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{
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pth_lock *thelock = (pth_lock *)lock;
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int status, error = 0;
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dprintf(("PyThread_release_lock(%p) called\n", lock));
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status = pth_mutex_acquire( &thelock->mut, 0, NULL );
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CHECK_STATUS("pth_mutex_acquire[3]");
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thelock->locked = 0;
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status = pth_mutex_release( &thelock->mut );
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CHECK_STATUS("pth_mutex_release[3]");
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/* wake up someone (anyone, if any) waiting on the lock */
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status = pth_cond_notify( &thelock->lock_released, 0 );
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CHECK_STATUS("pth_cond_notify");
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}
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