/* * The constructors. */ struct tls_tcb * _tcb_ctor(struct pthread *thread, int initial) { struct tls_tcb *tcb; if (initial) tcb = tls_get_tcb(); else tcb = _libc_allocate_tls(); if (tcb == NULL) return (NULL); tcb->tcb_pthread = thread; return (tcb); }
int _pthread_create(pthread_t *thread, const pthread_attr_t *attr, void *(*start_routine) (void *), void *arg) { struct pthread *curthread = _get_curthread(); struct itimerval itimer; int f_gc = 0; int ret = 0; pthread_t gc_thread; pthread_t new_thread; pthread_attr_t pattr; void *stack; if (thread == NULL) return (EINVAL); /* * Locking functions in libc are required when there are * threads other than the initial thread. */ __isthreaded = 1; /* Allocate memory for the thread structure: */ if ((new_thread = (pthread_t) malloc(sizeof(struct pthread))) == NULL) { /* Insufficient memory to create a thread: */ ret = EAGAIN; } else { /* Check if default thread attributes are required: */ if (attr == NULL || *attr == NULL) { /* Use the default thread attributes: */ pattr = &pthread_attr_default; } else { pattr = *attr; } /* Check if a stack was specified in the thread attributes: */ if ((stack = pattr->stackaddr_attr) != NULL) { } /* Allocate memory for a default-size stack: */ else if (pattr->stacksize_attr == PTHREAD_STACK_DEFAULT) { struct stack *spare_stack; /* Allocate or re-use a default-size stack. */ /* * Use the garbage collector mutex for synchronization * of the spare stack list. */ if (pthread_mutex_lock(&_gc_mutex) != 0) PANIC("Cannot lock gc mutex"); if ((spare_stack = SLIST_FIRST(&_stackq)) != NULL) { /* Use the spare stack. */ SLIST_REMOVE_HEAD(&_stackq, qe); /* Unlock the garbage collector mutex. */ if (pthread_mutex_unlock(&_gc_mutex) != 0) PANIC("Cannot unlock gc mutex"); stack = sizeof(struct stack) + (void *) spare_stack - PTHREAD_STACK_DEFAULT; } else { /* Allocate a new stack. */ stack = _next_stack + PTHREAD_STACK_GUARD; /* * Even if stack allocation fails, we don't want * to try to use this location again, so * unconditionally decrement _next_stack. Under * normal operating conditions, the most likely * reason for an mmap() error is a stack * overflow of the adjacent thread stack. */ _next_stack -= (PTHREAD_STACK_DEFAULT + PTHREAD_STACK_GUARD); /* Unlock the garbage collector mutex. */ if (pthread_mutex_unlock(&_gc_mutex) != 0) PANIC("Cannot unlock gc mutex"); /* Stack: */ if (mmap(stack, PTHREAD_STACK_DEFAULT, PROT_READ | PROT_WRITE, MAP_STACK, -1, 0) == MAP_FAILED) { ret = EAGAIN; free(new_thread); } } } /* * The user wants a stack of a particular size. Lets hope they * really know what they want, and simply malloc the stack. */ else if ((stack = (void *) malloc(pattr->stacksize_attr)) == NULL) { /* Insufficient memory to create a thread: */ ret = EAGAIN; free(new_thread); } /* Check for errors: */ if (ret != 0) { } else { /* Initialise the thread structure: */ memset(new_thread, 0, sizeof(struct pthread)); new_thread->tcb = _libc_allocate_tls(); if (new_thread->tcb == NULL) PANIC("Cannot allocate TLS and TCB"); new_thread->slice_usec = -1; new_thread->stack = stack; new_thread->start_routine = start_routine; new_thread->arg = arg; new_thread->cancelflags = PTHREAD_CANCEL_ENABLE | PTHREAD_CANCEL_DEFERRED; /* * Write a magic value to the thread structure * to help identify valid ones: */ new_thread->magic = PTHREAD_MAGIC; /* Initialise the thread for signals: */ new_thread->sigmask = curthread->sigmask; new_thread->sigmask_seqno = 0; /* Initialize the signal frame: */ new_thread->curframe = NULL; /* Initialise the jump buffer: */ _setjmp(new_thread->ctx.jb); /* * Set up new stack frame so that it looks like it * returned from a longjmp() to the beginning of * _thread_start(). */ SET_RETURN_ADDR_JB(new_thread->ctx.jb, _thread_start); /* The stack starts high and builds down: */ SET_STACK_JB(new_thread->ctx.jb, (long)new_thread->stack + pattr->stacksize_attr - sizeof(double)); /* Copy the thread attributes: */ memcpy(&new_thread->attr, pattr, sizeof(struct pthread_attr)); /* * Check if this thread is to inherit the scheduling * attributes from its parent: */ if (new_thread->attr.flags & PTHREAD_INHERIT_SCHED) { /* Copy the scheduling attributes: */ new_thread->base_priority = curthread->base_priority & ~PTHREAD_SIGNAL_PRIORITY; new_thread->attr.prio = curthread->base_priority & ~PTHREAD_SIGNAL_PRIORITY; new_thread->attr.sched_policy = curthread->attr.sched_policy; } else { /* * Use just the thread priority, leaving the * other scheduling attributes as their * default values: */ new_thread->base_priority = new_thread->attr.prio; } new_thread->active_priority = new_thread->base_priority; new_thread->inherited_priority = 0; /* Initialize joiner to NULL (no joiner): */ new_thread->joiner = NULL; /* Initialize the mutex queue: */ TAILQ_INIT(&new_thread->mutexq); /* Initialise hooks in the thread structure: */ new_thread->specific_data = NULL; new_thread->cleanup = NULL; new_thread->flags = 0; new_thread->poll_data.nfds = 0; new_thread->poll_data.fds = NULL; new_thread->continuation = NULL; /* * Defer signals to protect the scheduling queues * from access by the signal handler: */ _thread_kern_sig_defer(); /* * Initialise the unique id which GDB uses to * track threads. */ new_thread->uniqueid = next_uniqueid++; /* * Check if the garbage collector thread * needs to be started. */ f_gc = (TAILQ_FIRST(&_thread_list) == _thread_initial); /* Add the thread to the linked list of all threads: */ TAILQ_INSERT_HEAD(&_thread_list, new_thread, tle); if (pattr->suspend == PTHREAD_CREATE_SUSPENDED) { new_thread->flags |= PTHREAD_FLAGS_SUSPENDED; new_thread->state = PS_SUSPENDED; } else { new_thread->state = PS_RUNNING; PTHREAD_PRIOQ_INSERT_TAIL(new_thread); } /* * Undefer and handle pending signals, yielding * if necessary. */ _thread_kern_sig_undefer(); /* Return a pointer to the thread structure: */ (*thread) = new_thread; if (f_gc != 0) { /* Install the scheduling timer: */ itimer.it_interval.tv_sec = 0; itimer.it_interval.tv_usec = _clock_res_usec; itimer.it_value = itimer.it_interval; if (setitimer(_ITIMER_SCHED_TIMER, &itimer, NULL) != 0) PANIC("Cannot set interval timer"); } /* Schedule the new user thread: */ _thread_kern_sched(NULL); /* * Start a garbage collector thread * if necessary. */ if (f_gc && pthread_create(&gc_thread,NULL, _thread_gc,NULL) != 0) PANIC("Can't create gc thread"); } } /* Return the status: */ return (ret); }