Clean up more code

The *NSYNC linked list API is good enough that it deserves to be part of
the C libray, so this change writes an improved version of it which uses
that offsetof() trick from the Linux Kernel. We vendor all of the *NSYNC
tests in third_party which helped confirm the needed refactoring is safe

This change also deletes more old code that didn't pan out. My goal here
is to work towards a vision where the Cosmopolitan core libraries become
less experimental and more focused on curation. This better reflects the
current level of quality we've managed to achieve.

libc/thread/posixthread.internal.h

@@ -2,10 +2,10 @@
 #define COSMOPOLITAN_LIBC_THREAD_POSIXTHREAD_INTERNAL_H_
 #include "libc/calls/struct/sched_param.h"
 #include "libc/calls/struct/sigset.h"
+#include "libc/intrin/dll.h"
 #include "libc/runtime/runtime.h"
 #include "libc/thread/thread.h"
 #include "libc/thread/tls.h"
-#include "third_party/nsync/dll.h"
 
 #define PT_OWNSTACK       1
 #define PT_STATIC         2
@@ -64,26 +64,28 @@ enum PosixThreadStatus {
   kPosixThreadZombie,
 };
 
+#define POSIXTHREAD_CONTAINER(e) DLL_CONTAINER(struct PosixThread, list, e)
+
 struct PosixThread {
   int flags;               // 0x00: see PT_* constants
   _Atomic(int) cancelled;  // 0x04: thread has bad beliefs
   _Atomic(enum PosixThreadStatus) status;
-  _Atomic(int) ptid;        // transitions 0 → tid
-  void *(*start)(void *);   // creation callback
-  void *arg;                // start's parameter
-  void *rc;                 // start's return value
-  char *altstack;           // thread sigaltstack
-  char *tls;                // bottom of tls allocation
-  struct CosmoTib *tib;     // middle of tls allocation
-  nsync_dll_element_ list;  // list of threads
-  jmp_buf exiter;           // for pthread_exit
+  _Atomic(int) ptid;       // transitions 0 → tid
+  void *(*start)(void *);  // creation callback
+  void *arg;               // start's parameter
+  void *rc;                // start's return value
+  char *altstack;          // thread sigaltstack
+  char *tls;               // bottom of tls allocation
+  struct CosmoTib *tib;    // middle of tls allocation
+  struct Dll list;         // list of threads
+  jmp_buf exiter;          // for pthread_exit
   pthread_attr_t attr;
   struct _pthread_cleanup_buffer *cleanup;
 };
 
 typedef void (*atfork_f)(void);
 
-extern nsync_dll_list_ _pthread_list;
+extern struct Dll *_pthread_list;
 extern pthread_spinlock_t _pthread_lock;
 extern _Atomic(pthread_key_dtor) _pthread_key_dtor[PTHREAD_KEYS_MAX] _Hide;
 

libc/thread/pthread_atfork.c

@@ -20,6 +20,7 @@
 #include "libc/calls/state.internal.h"
 #include "libc/errno.h"
 #include "libc/intrin/atomic.h"
+#include "libc/intrin/dll.h"
 #include "libc/intrin/kmalloc.h"
 #include "libc/mem/mem.h"
 #include "libc/runtime/memtrack.internal.h"
@@ -37,10 +38,10 @@ static struct AtForks {
 } _atforks;
 
 static void _pthread_purge(void) {
-  nsync_dll_element_ *e;
-  while ((e = nsync_dll_first_(_pthread_list))) {
-    _pthread_list = nsync_dll_remove_(_pthread_list, e);
-    _pthread_free(e->container);
+  struct Dll *e;
+  while ((e = dll_first(_pthread_list))) {
+    dll_remove(&_pthread_list, e);
+    _pthread_free(POSIXTHREAD_CONTAINER(e));
   }
 }
 
@@ -97,9 +98,9 @@ void _pthread_onfork_child(void) {
 
   // delete other threads that existed before forking
   // this must come after onfork, since it calls free
-  _pthread_list = nsync_dll_remove_(_pthread_list, &pt->list);
+  dll_remove(&_pthread_list, &pt->list);
   _pthread_purge();
-  _pthread_list = nsync_dll_make_first_in_list_(_pthread_list, &pt->list);
+  dll_make_first(&_pthread_list, &pt->list);
 }
 
 int _pthread_atfork(atfork_f prepare, atfork_f parent, atfork_f child) {

libc/thread/pthread_create.c

@@ -26,10 +26,10 @@
 #include "libc/intrin/asan.internal.h"
 #include "libc/intrin/atomic.h"
 #include "libc/intrin/bits.h"
+#include "libc/intrin/dll.h"
 #include "libc/log/internal.h"
 #include "libc/macros.internal.h"
 #include "libc/mem/mem.h"
-#include "libc/runtime/clone.internal.h"
 #include "libc/runtime/runtime.h"
 #include "libc/runtime/stack.h"
 #include "libc/str/str.h"
@@ -43,7 +43,6 @@
 #include "libc/thread/thread.h"
 #include "libc/thread/tls.h"
 #include "libc/thread/wait0.internal.h"
-#include "third_party/nsync/dll.h"
 
 STATIC_YOINK("nsync_mu_lock");
 STATIC_YOINK("nsync_mu_unlock");
@@ -246,9 +245,9 @@ static errno_t pthread_create_impl(pthread_t *thread,
 
   // add thread to global list
   // we add it to the end since zombies go at the beginning
-  nsync_dll_init_(&pt->list, pt);
+  dll_init(&pt->list);
   pthread_spin_lock(&_pthread_lock);
-  _pthread_list = nsync_dll_make_last_in_list_(_pthread_list, &pt->list);
+  dll_make_last(&_pthread_list, &pt->list);
   pthread_spin_unlock(&_pthread_lock);
 
   // launch PosixThread(pt) in new thread
@@ -260,7 +259,7 @@ static errno_t pthread_create_impl(pthread_t *thread,
                       CLONE_CHILD_CLEARTID,
                   pt, &pt->ptid, __adj_tls(pt->tib), &pt->tib->tib_tid))) {
     pthread_spin_lock(&_pthread_lock);
-    _pthread_list = nsync_dll_remove_(_pthread_list, &pt->list);
+    dll_remove(&_pthread_list, &pt->list);
     pthread_spin_unlock(&_pthread_lock);
     _pthread_free(pt);
     return rc;

libc/thread/pthread_decimate_np.c

@@ -17,29 +17,28 @@
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/intrin/atomic.h"
+#include "libc/intrin/dll.h"
 #include "libc/runtime/runtime.h"
 #include "libc/thread/posixthread.internal.h"
 #include "libc/thread/thread.h"
 #include "libc/thread/tls.h"
-#include "third_party/nsync/dll.h"
 
 /**
  * Releases memory of detached threads that have terminated.
  */
 void pthread_decimate_np(void) {
-  nsync_dll_element_ *e;
+  struct Dll *e;
   struct PosixThread *pt;
   enum PosixThreadStatus status;
 StartOver:
   pthread_spin_lock(&_pthread_lock);
-  for (e = nsync_dll_first_(_pthread_list); e;
-       e = nsync_dll_next_(_pthread_list, e)) {
-    pt = (struct PosixThread *)e->container;
+  for (e = dll_first(_pthread_list); e; e = dll_next(_pthread_list, e)) {
+    pt = POSIXTHREAD_CONTAINER(e);
     if (pt->tib == __get_tls()) continue;
     status = atomic_load_explicit(&pt->status, memory_order_acquire);
     if (status != kPosixThreadZombie) break;
     if (!atomic_load_explicit(&pt->tib->tib_tid, memory_order_acquire)) {
-      _pthread_list = nsync_dll_remove_(_pthread_list, e);
+      dll_remove(&_pthread_list, e);
       pthread_spin_unlock(&_pthread_lock);
       _pthread_free(pt);
       goto StartOver;

libc/thread/pthread_detach.c

@@ -25,7 +25,6 @@
 #include "libc/thread/posixthread.internal.h"
 #include "libc/thread/spawn.h"
 #include "libc/thread/thread.h"
-#include "third_party/nsync/dll.h"
 
 /**
  * Asks POSIX thread to free itself automatically upon termination.

libc/thread/pthread_exit.c

@@ -29,7 +29,6 @@
 #include "libc/thread/posixthread.internal.h"
 #include "libc/thread/thread.h"
 #include "libc/thread/tls.h"
-#include "third_party/nsync/dll.h"
 #include "third_party/nsync/futex.internal.h"
 
 static void CleanupThread(struct PosixThread *pt) {

libc/thread/pthread_print_np.c

@@ -1,91 +0,0 @@
-/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
-│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
-╞══════════════════════════════════════════════════════════════════════════════╡
-│ Copyright 2022 Justine Alexandra Roberts Tunney                              │
-│                                                                              │
-│ Permission to use, copy, modify, and/or distribute this software for         │
-│ any purpose with or without fee is hereby granted, provided that the         │
-│ above copyright notice and this permission notice appear in all copies.      │
-│                                                                              │
-│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
-│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
-│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
-│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
-│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
-│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
-│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
-│ PERFORMANCE OF THIS SOFTWARE.                                                │
-╚─────────────────────────────────────────────────────────────────────────────*/
-#include "libc/calls/blockcancel.internal.h"
-#include "libc/calls/calls.h"
-#include "libc/intrin/kprintf.h"
-#include "libc/runtime/runtime.h"
-#include "libc/str/str.h"
-#include "libc/thread/posixthread.internal.h"
-#include "libc/thread/thread.h"
-#include "third_party/nsync/dll.h"
-
-#define N 2048
-#define M 15
-
-#define append(f, ...) o += f(buf + o, N - o, __VA_ARGS__)
-
-static const char *DescribeStatus(enum PosixThreadStatus status) {
-  switch (status) {
-    case kPosixThreadJoinable:
-      return "JOINAB";
-    case kPosixThreadDetached:
-      return "DETACH";
-    case kPosixThreadTerminated:
-      return "TERMIN";
-    case kPosixThreadZombie:
-      return "ZOMBIE";
-    default:
-      __builtin_unreachable();
-  }
-}
-
-static const char *DescribeFlags(char buf[M], struct PosixThread *pt) {
-  char *p = buf;
-  if (pt->cancelled) *p++ = '*';
-  if (pt->flags & PT_EXITING) *p++ = 'X';
-  if (pt->flags & PT_STATIC) *p++ = 'S';
-  if (pt->flags & PT_OWNSTACK) *p++ = 'O';
-  if (pt->flags & PT_ASYNC) *p++ = 'A';
-  if (pt->flags & PT_MASKED) *p++ = 'M';
-  if (pt->flags & PT_OPENBSD_KLUDGE) *p++ = 'K';
-  if (pt->flags & PT_INCANCEL) *p++ = '?';
-  if (pt->flags & PT_NOCANCEL) *p++ = '!';
-  *p = 0;
-  return buf;
-}
-
-int pthread_print_np(int fd, const char *fmt, ...) {
-  va_list va;
-  int rc, o = 0;
-  nsync_dll_element_ *e;
-  struct PosixThread *pt;
-  char buf[N], flagbuf[M];
-  pthread_spin_lock(&_pthread_lock);
-  if (fmt) {
-    va_start(va, fmt);
-    append(kvsnprintf, fmt, va);
-    va_end(va);
-    append(ksnprintf, "\n");
-  }
-  append(ksnprintf, "%6s %6s %6s %6s %s\n", "ptid", "tid", "status", "flags",
-         "start");
-  for (e = nsync_dll_first_(_pthread_list); e;
-       e = nsync_dll_next_(_pthread_list, e)) {
-    pt = (struct PosixThread *)e->container;
-    append(ksnprintf, "%-6d %-6d %6s %6s %t\n", pt->ptid, pt->tib->tib_tid,
-           DescribeStatus(pt->status), DescribeFlags(flagbuf, pt), pt->start);
-  }
-  pthread_spin_unlock(&_pthread_lock);
-  BLOCK_CANCELLATIONS;
-  strace_enabled(-1);
-  rc = write(fd, buf, strlen(buf));
-  strace_enabled(+1);
-  ALLOW_CANCELLATIONS;
-  return rc;
-}

libc/thread/pthread_timedjoin_np.c

@@ -20,6 +20,7 @@
 #include "libc/calls/struct/timespec.h"
 #include "libc/errno.h"
 #include "libc/intrin/atomic.h"
+#include "libc/intrin/dll.h"
 #include "libc/thread/posixthread.internal.h"
 #include "libc/thread/thread2.h"
 #include "libc/thread/tls.h"
@@ -60,7 +61,7 @@ errno_t pthread_timedjoin_np(pthread_t thread, void **value_ptr,
   _unassert(status == kPosixThreadJoinable || status == kPosixThreadTerminated);
   if (!(rc = _wait0(&pt->tib->tib_tid, abstime))) {
     pthread_spin_lock(&_pthread_lock);
-    _pthread_list = nsync_dll_remove_(_pthread_list, &pt->list);
+    dll_remove(&_pthread_list, &pt->list);
     pthread_spin_unlock(&_pthread_lock);
     if (value_ptr) {
       *value_ptr = pt->rc;

libc/thread/pthread_zombify.c

@@ -16,13 +16,13 @@
 │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/intrin/dll.h"
 #include "libc/thread/posixthread.internal.h"
 #include "libc/thread/thread.h"
-#include "third_party/nsync/dll.h"
 
 void _pthread_zombify(struct PosixThread *pt) {
   pthread_spin_lock(&_pthread_lock);
-  _pthread_list = nsync_dll_remove_(_pthread_list, &pt->list);
-  _pthread_list = nsync_dll_make_first_in_list_(_pthread_list, &pt->list);
+  dll_remove(&_pthread_list, &pt->list);
+  dll_make_first(&_pthread_list, &pt->list);
   pthread_spin_unlock(&_pthread_lock);
 }

libc/thread/spawn.c

@@ -22,7 +22,6 @@
 #include "libc/errno.h"
 #include "libc/macros.internal.h"
 #include "libc/mem/mem.h"
-#include "libc/runtime/clone.internal.h"
 #include "libc/runtime/internal.h"
 #include "libc/runtime/runtime.h"
 #include "libc/runtime/stack.h"

libc/thread/thread.h

@@ -170,7 +170,6 @@ int pthread_mutexattr_setpshared(pthread_mutexattr_t *, int) paramsnonnull();
 int pthread_mutexattr_settype(pthread_mutexattr_t *, int) paramsnonnull();
 int pthread_once(pthread_once_t *, void (*)(void)) paramsnonnull();
 int pthread_orphan_np(void);
-int pthread_print_np(int, const char *, ...);
 int pthread_rwlock_destroy(pthread_rwlock_t *) paramsnonnull();
 int pthread_rwlock_init(pthread_rwlock_t *, const pthread_rwlockattr_t *) paramsnonnull((1));
 int pthread_rwlock_rdlock(pthread_rwlock_t *) paramsnonnull();