Clean up some of the threading code

libc/calls/atfork.c

@@ -1,62 +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 2020 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/intrin/cmpxchg.h"
-#include "libc/macros.internal.h"
-#include "libc/runtime/runtime.h"
-#include "libc/sysv/errfuns.h"
-
-static struct AtFork {
-  volatile size_t i;
-  struct AtForkCallback {
-    void (*fn)(void *);
-    void *arg;
-  } p[ATEXIT_MAX];
-} g_atfork;
-
-/**
- * Registers function to be called by fork() in child.
- *
- * @return 0 on success, or -1 w/ errno
- * @note vfork() won't invoke callbacks
- * @asyncsignalsafe
- */
-int atfork(void *fn, void *arg) {
-  size_t i;
-  for (;;) {
-    i = g_atfork.i;
-    if (i == ARRAYLEN(g_atfork.p)) return enomem();
-    if (_cmpxchg(&g_atfork.i, i, i + 1)) {
-      g_atfork.p[i] = (struct AtForkCallback){.fn = fn, .arg = arg};
-      return 0;
-    }
-  }
-}
-
-/**
- * Triggers callbacks registered by atfork().
- *
- * @note only fork() should call this
- * @asyncsignalsafe
- */
-void __onfork(void) {
-  size_t i;
-  for (i = 0; i < g_atfork.i; ++i) {
-    g_atfork.p[i].fn(g_atfork.p[i].arg);
-  }
-}

libc/calls/state.internal.h

@@ -1,6 +1,7 @@
 #ifndef COSMOPOLITAN_LIBC_CALLS_STATE_INTERNAL_H_
 #define COSMOPOLITAN_LIBC_CALLS_STATE_INTERNAL_H_
 #include "libc/intrin/nopl.h"
+#include "libc/intrin/pthread.h"
 #include "libc/nexgen32e/threaded.h"
 #if !(__ASSEMBLER__ + __LINKER__ + 0)
 COSMOPOLITAN_C_START_
@@ -9,6 +10,7 @@ hidden extern int __vforked;
 hidden extern bool __time_critical;
 hidden extern unsigned __sighandrvas[NSIG];
 hidden extern unsigned __sighandflags[NSIG];
+hidden extern pthread_mutex_t __fds_lock_obj;
 hidden extern const struct NtSecurityAttributes kNtIsInheritable;
 
 void __fds_lock(void);

libc/calls/symlinkat-nt.c

@@ -19,7 +19,7 @@
 #include "libc/calls/calls.h"
 #include "libc/calls/syscall_support-nt.internal.h"
 #include "libc/errno.h"
-#include "libc/intrin/once.h"
+#include "libc/intrin/pthread.h"
 #include "libc/nt/enum/accessmask.h"
 #include "libc/nt/enum/fileflagandattributes.h"
 #include "libc/nt/enum/symboliclink.h"
@@ -35,17 +35,20 @@
 
 __msabi extern typeof(GetFileAttributes) *const __imp_GetFileAttributesW;
 
-static bool AllowedToCreateSymlinks(void) {
+static _Bool g_winlink_allowed;
+static pthread_once_t g_winlink_once;
+
+static textwindows void InitializeWinlink(void) {
   int64_t tok;
   struct NtLuid id;
   struct NtTokenPrivileges tp;
-  if (!OpenProcessToken(GetCurrentProcess(), kNtTokenAllAccess, &tok)) return 0;
-  if (!LookupPrivilegeValue(0, u"SeCreateSymbolicLinkPrivilege", &id)) return 0;
+  if (!OpenProcessToken(GetCurrentProcess(), kNtTokenAllAccess, &tok)) return;
+  if (!LookupPrivilegeValue(0, u"SeCreateSymbolicLinkPrivilege", &id)) return;
   tp.PrivilegeCount = 1;
   tp.Privileges[0].Luid = id;
   tp.Privileges[0].Attributes = kNtSePrivilegeEnabled;
-  if (!AdjustTokenPrivileges(tok, 0, &tp, sizeof(tp), 0, 0)) return 0;
-  return GetLastError() != kNtErrorNotAllAssigned;
+  if (!AdjustTokenPrivileges(tok, 0, &tp, sizeof(tp), 0, 0)) return;
+  g_winlink_allowed = GetLastError() != kNtErrorNotAllAssigned;
 }
 
 textwindows int sys_symlinkat_nt(const char *target, int newdirfd,
@@ -79,7 +82,8 @@ textwindows int sys_symlinkat_nt(const char *target, int newdirfd,
 
   // windows only lets administrators do this
   // even then we're required to ask for permission
-  if (!_once(AllowedToCreateSymlinks())) {
+  pthread_once(&g_winlink_once, InitializeWinlink);
+  if (!g_winlink_allowed) {
     return eperm();
   }