mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-01-31 19:43:32 +00:00
0d748ad58e
This change fixes Cosmopolitan so it has fewer opinions about compiler warnings. The whole repository had to be cleaned up to be buildable in -Werror -Wall mode. This lets us benefit from things like strict const checking. Some actual bugs might have been caught too.
120 lines
4.4 KiB
C
120 lines
4.4 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/state.internal.h"
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#include "libc/errno.h"
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#include "libc/intrin/atomic.h"
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#include "libc/intrin/dll.h"
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#include "libc/intrin/kmalloc.h"
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#include "libc/mem/mem.h"
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#include "libc/runtime/memtrack.internal.h"
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#include "libc/str/str.h"
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#include "libc/thread/posixthread.internal.h"
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#include "libc/thread/thread.h"
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#include "libc/thread/tls.h"
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static struct AtForks {
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pthread_spinlock_t lock;
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struct AtFork {
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struct AtFork *p[2];
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atfork_f f[3];
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} * list;
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} _atforks;
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static void _pthread_purge(void) {
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struct Dll *e;
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while ((e = dll_first(_pthread_list))) {
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dll_remove(&_pthread_list, e);
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_pthread_free(POSIXTHREAD_CONTAINER(e));
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}
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}
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static void _pthread_onfork(int i) {
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struct AtFork *a;
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unassert(0 <= i && i <= 2);
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if (!i) pthread_spin_lock(&_atforks.lock);
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for (a = _atforks.list; a; a = a->p[!i]) {
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if (a->f[i]) a->f[i]();
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_atforks.list = a;
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}
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if (i) pthread_spin_unlock(&_atforks.lock);
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}
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void _pthread_onfork_prepare(void) {
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_pthread_onfork(0);
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pthread_spin_lock(&_pthread_lock);
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__fds_lock();
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__mmi_lock();
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__kmalloc_lock();
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}
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void _pthread_onfork_parent(void) {
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__kmalloc_unlock();
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__mmi_unlock();
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__fds_unlock();
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pthread_spin_unlock(&_pthread_lock);
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_pthread_onfork(1);
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}
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void _pthread_onfork_child(void) {
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struct CosmoTib *tib;
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struct PosixThread *pt;
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pthread_mutexattr_t attr;
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extern pthread_mutex_t __mmi_lock_obj;
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tib = __get_tls();
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pt = (struct PosixThread *)tib->tib_pthread;
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// let's choose to let the new process live.
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// even though it's unclear what to do with this kind of race.
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atomic_store_explicit(&pt->cancelled, false, memory_order_relaxed);
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// wipe core runtime locks
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__kmalloc_unlock();
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pthread_mutexattr_init(&attr);
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pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
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pthread_mutex_init(&__mmi_lock_obj, &attr);
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pthread_mutex_init(&__fds_lock_obj, &attr);
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(void)pthread_spin_init(&_pthread_lock, 0);
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// call user-supplied forked child callbacks
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_pthread_onfork(2);
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// delete other threads that existed before forking
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// this must come after onfork, since it calls free
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dll_remove(&_pthread_list, &pt->list);
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_pthread_purge();
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dll_make_first(&_pthread_list, &pt->list);
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}
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int _pthread_atfork(atfork_f prepare, atfork_f parent, atfork_f child) {
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int rc;
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struct AtFork *a;
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if (!(a = kmalloc(sizeof(struct AtFork)))) return ENOMEM;
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a->f[0] = prepare;
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a->f[1] = parent;
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a->f[2] = child;
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pthread_spin_lock(&_atforks.lock);
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a->p[0] = 0;
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a->p[1] = _atforks.list;
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if (_atforks.list) _atforks.list->p[0] = a;
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_atforks.list = a;
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pthread_spin_unlock(&_atforks.lock);
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rc = 0;
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return rc;
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}
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