mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-02-07 23:13:34 +00:00
244 lines
9 KiB
C
244 lines
9 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2022 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/assert.h"
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#include "libc/calls/calls.h"
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#include "libc/errno.h"
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#include "libc/intrin/asan.internal.h"
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#include "libc/intrin/atomic.h"
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#include "libc/intrin/pthread.h"
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#include "libc/intrin/wait0.internal.h"
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#include "libc/intrin/weaken.h"
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#include "libc/mem/mem.h"
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#include "libc/nexgen32e/gc.internal.h"
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#include "libc/nexgen32e/gettls.h"
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#include "libc/nexgen32e/threaded.h"
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#include "libc/runtime/runtime.h"
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#include "libc/sysv/consts/clone.h"
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#include "libc/sysv/consts/map.h"
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#include "libc/sysv/consts/prot.h"
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#include "libc/thread/internal.h"
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#include "libc/thread/posixthread.internal.h"
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#include "libc/thread/spawn.h"
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#include "libc/thread/thread.h"
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void _pthread_wait(struct PosixThread *pt) {
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_wait0(pt->spawn.ctid);
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}
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void _pthread_free(struct PosixThread *pt) {
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free(pt->spawn.tls);
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if (pt->stacksize) {
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munmap(&pt->spawn.stk, pt->stacksize);
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}
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free(pt);
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}
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static int PosixThread(void *arg, int tid) {
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struct PosixThread *pt = arg;
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enum PosixThreadStatus status;
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if (!setjmp(pt->exiter)) {
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((cthread_t)__get_tls())->pthread = (pthread_t)pt;
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pt->rc = pt->start_routine(pt->arg);
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}
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if (weaken(_pthread_key_destruct)) {
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weaken(_pthread_key_destruct)(0);
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}
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cthread_ungarbage();
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if (atomic_load_explicit(&pt->status, memory_order_acquire) ==
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kPosixThreadDetached) {
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atomic_store_explicit(&pt->status, kPosixThreadZombie,
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memory_order_release);
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} else {
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atomic_store_explicit(&pt->status, kPosixThreadTerminated,
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memory_order_release);
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}
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return 0;
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}
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/**
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* Creates thread, e.g.
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*
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* void *worker(void *arg) {
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* fputs(arg, stdout);
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* return "there\n";
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* }
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*
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* int main() {
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* void *result;
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* pthread_t id;
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* pthread_create(&id, 0, worker, "hi ");
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* pthread_join(id, &result);
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* fputs(result, stdout);
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* }
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*
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* Here's the OSI model of threads in Cosmopolitan:
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*
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* ┌──────────────────┐
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* │ pthread_create() │ - Standard
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* └─────────┬────────┘ Abstraction
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* ┌─────────┴────────┐
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* │ clone() │ - Polyfill
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* └─────────┬────────┘
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* ┌────────┬──┴┬─┬─┬─────────┐ - Kernel
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* ┌─────┴─────┐ │ │ │┌┴──────┐ │ Interfaces
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* │ sys_clone │ │ │ ││ tfork │ ┌┴─────────────┐
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* └───────────┘ │ │ │└───────┘ │ CreateThread │
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* ┌───────────────┴──┐│┌┴────────┐ └──────────────┘
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* │ bsdthread_create │││ thr_new │
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* └──────────────────┘│└─────────┘
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* ┌───────┴──────┐
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* │ _lwp_create │
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* └──────────────┘
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*
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* @param thread if non-null is used to output the thread id
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* upon successful completion
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* @param attr points to launch configuration, or may be null
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* to use sensible defaults; it must be initialized using
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* pthread_attr_init()
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* @param start_routine is your thread's callback function
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* @param arg is an arbitrary value passed to `start_routine`
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* @return 0 on success, or errno on error
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* @raise EAGAIN if resources to create thread weren't available
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* @raise EINVAL if `attr` was supplied and had unnaceptable data
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* @raise EPERM if scheduling policy was requested and user account
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* isn't authorized to use it
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* @threadsafe
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*/
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int pthread_create(pthread_t *thread, const pthread_attr_t *attr,
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void *(*start_routine)(void *), void *arg) {
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int rc, e = errno;
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struct PosixThread *pt;
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pthread_attr_t default_attr;
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TlsIsRequired();
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_pthread_zombies_decimate();
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// default attributes
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if (!attr) {
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pthread_attr_init(&default_attr);
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attr = &default_attr;
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}
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// create posix thread object
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if (!(pt = calloc(1, sizeof(struct PosixThread)))) {
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errno = e;
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return EAGAIN;
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}
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pt->start_routine = start_routine;
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pt->arg = arg;
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// create thread local storage memory
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if (!(pt->spawn.tls = _mktls(&pt->spawn.tib))) {
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free(pt);
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errno = e;
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return EAGAIN;
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}
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// child thread id is also a condition variable
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pt->spawn.ctid = (int *)(pt->spawn.tib + 0x38);
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// create stack
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if (attr && attr->stackaddr) {
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// caller is responsible for creating stacks
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pt->spawn.stk = attr->stackaddr;
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} else {
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// cosmo posix threads is managing the stack
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pt->spawn.stk = mmap(0, attr->stacksize, PROT_READ | PROT_WRITE,
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MAP_STACK | MAP_ANONYMOUS, -1, 0);
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if (pt->spawn.stk != MAP_FAILED) {
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pt->stacksize = attr->stacksize;
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} else {
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rc = errno;
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_pthread_free(pt);
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errno = e;
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if (rc == EINVAL || rc == EOVERFLOW) {
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return EINVAL;
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} else {
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return EAGAIN;
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}
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}
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// mmap(MAP_STACK) creates a 4096 guard by default
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if (attr->guardsize != PAGESIZE) {
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// user requested special guard size
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if (attr->guardsize) {
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rc = mprotect(pt->spawn.stk, attr->guardsize, PROT_NONE);
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} else {
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rc = mprotect(pt->spawn.stk, PAGESIZE, PROT_READ | PROT_WRITE);
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}
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if (rc) {
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notpossible;
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}
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}
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if (IsAsan()) {
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if (attr->guardsize) {
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__asan_poison(pt->spawn.stk, attr->guardsize, kAsanStackOverflow);
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}
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__asan_poison(
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pt->spawn.stk + attr->stacksize - 16 /* openbsd:stackbound */, 16,
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kAsanStackOverflow);
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}
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}
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// we only need to save this to support pthread_getattr_np()
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pt->attr = *attr;
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// if attr->stackaddr == 0,
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// the stack is managed by cosmo,
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// pt->spawn.stk is from a successful mmap,
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// and so pt->attr.stackaddr = pt->spawn.stk
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pt->attr.stackaddr = pt->spawn.stk;
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// if attr->stackaddr != 0,
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// then stack is not managed by cosmo
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// pt->attr.stackaddr = pt->spawn.stk = attr->stackaddr
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// so the above line is a no-op.
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// set initial status
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switch (attr->detachstate) {
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case PTHREAD_CREATE_JOINABLE:
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pt->status = kPosixThreadJoinable;
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break;
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case PTHREAD_CREATE_DETACHED:
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pt->status = kPosixThreadDetached;
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_pthread_zombies_add(pt);
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break;
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default:
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_pthread_free(pt);
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return EINVAL;
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}
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// launch PosixThread(pt) in new thread
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if (clone(PosixThread, pt->spawn.stk,
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attr->stacksize - 16 /* openbsd:stackbound */,
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CLONE_VM | CLONE_THREAD | CLONE_FS | CLONE_FILES | CLONE_SIGHAND |
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CLONE_SETTLS | CLONE_PARENT_SETTID | CLONE_CHILD_SETTID |
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CLONE_CHILD_CLEARTID,
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pt, &pt->spawn.ptid, pt->spawn.tib, pt->spawn.ctid) == -1) {
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rc = errno;
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_pthread_free(pt);
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errno = e;
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if (rc == EINVAL) {
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return EINVAL;
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} else {
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return EAGAIN;
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}
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}
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if (thread) {
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*thread = (pthread_t)pt;
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}
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return 0;
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}
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