code review 7543043: runtime: faster & safer hash function

src/pkg/runtime/thread_windows.c

 // Copyright 2009 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
 #include "runtime.h"
 #include "type.h"
 #include "defs_GOOS_GOARCH.h"
 #include "os_GOOS.h"
 
 #pragma dynimport runtime·CloseHandle CloseHandle "kernel32.dll"
 #pragma dynimport runtime·CreateEvent CreateEventA "kernel32.dll"
 #pragma dynimport runtime·CreateThread CreateThread "kernel32.dll"
 #pragma dynimport runtime·CreateWaitableTimer CreateWaitableTimerA "kernel32.dll"
+#pragma dynimport runtime·CryptAcquireContextW CryptAcquireContextW "advapi32.dll"
+#pragma dynimport runtime·CryptGenRandom CryptGenRandom "advapi32.dll"
+#pragma dynimport runtime·CryptReleaseContext CryptReleaseContext "advapi32.dll"
 #pragma dynimport runtime·DuplicateHandle DuplicateHandle "kernel32.dll"
 #pragma dynimport runtime·ExitProcess ExitProcess "kernel32.dll"
 #pragma dynimport runtime·FreeEnvironmentStringsW FreeEnvironmentStringsW "kernel32.dll"
 #pragma dynimport runtime·GetEnvironmentStringsW GetEnvironmentStringsW "kernel32.dll"
 #pragma dynimport runtime·GetProcAddress GetProcAddress "kernel32.dll"
 #pragma dynimport runtime·GetStdHandle GetStdHandle "kernel32.dll"
 #pragma dynimport runtime·GetSystemInfo GetSystemInfo "kernel32.dll"
 #pragma dynimport runtime·GetSystemTimeAsFileTime GetSystemTimeAsFileTime "kernel32.dll"
 #pragma dynimport runtime·GetThreadContext GetThreadContext "kernel32.dll"
 #pragma dynimport runtime·LoadLibrary LoadLibraryW "kernel32.dll"
 #pragma dynimport runtime·ResumeThread ResumeThread "kernel32.dll"
 #pragma dynimport runtime·SetConsoleCtrlHandler SetConsoleCtrlHandler "kernel32.dll"
 #pragma dynimport runtime·SetEvent SetEvent "kernel32.dll"
 #pragma dynimport runtime·SetThreadPriority SetThreadPriority "kernel32.dll"
 #pragma dynimport runtime·SetWaitableTimer SetWaitableTimer "kernel32.dll"
 #pragma dynimport runtime·Sleep Sleep "kernel32.dll"
 #pragma dynimport runtime·SuspendThread SuspendThread "kernel32.dll"
 #pragma dynimport runtime·timeBeginPeriod timeBeginPeriod "winmm.dll"
 #pragma dynimport runtime·WaitForSingleObject WaitForSingleObject "kernel32.dll"
 #pragma dynimport runtime·WriteFile WriteFile "kernel32.dll"
-#pragma dynimport runtime·CryptAcquireContextW CryptAcquireContextW "advapi32.dll"
-#pragma dynimport runtime·CryptGenRandom CryptGenRandom "advapi32.dll"
-#pragma dynimport runtime·CryptReleaseContext CryptReleaseContext "advapi32.dll"
+#pragma dynimport runtime·NtWaitForSingleObject NtWaitForSingleObject "ntdll.dll"
+
+extern void *runtime·NtWaitForSingleObject;
 
 extern void *runtime·CloseHandle;
 extern void *runtime·CreateEvent;
 extern void *runtime·CreateThread;
 extern void *runtime·CreateWaitableTimer;
+extern void *runtime·CryptAcquireContextW;
+extern void *runtime·CryptGenRandom;
+extern void *runtime·CryptReleaseContext;
 extern void *runtime·DuplicateHandle;
 extern void *runtime·ExitProcess;
 extern void *runtime·FreeEnvironmentStringsW;
 extern void *runtime·GetEnvironmentStringsW;
 extern void *runtime·GetProcAddress;
 extern void *runtime·GetStdHandle;
 extern void *runtime·GetSystemInfo;
 extern void *runtime·GetSystemTimeAsFileTime;
 extern void *runtime·GetThreadContext;
 extern void *runtime·LoadLibrary;
 extern void *runtime·ResumeThread;
 extern void *runtime·SetConsoleCtrlHandler;
 extern void *runtime·SetEvent;
 extern void *runtime·SetThreadPriority;
 extern void *runtime·SetWaitableTimer;
 extern void *runtime·Sleep;
 extern void *runtime·SuspendThread;
 extern void *runtime·timeBeginPeriod;
 extern void *runtime·WaitForSingleObject;
 extern void *runtime·WriteFile;
-extern void *runtime·CryptAcquireContextW;
-extern void *runtime·CryptGenRandom;
-extern void *runtime·CryptReleaseContext;
 
 static int32
 getproccount(void)
 {
         SystemInfo info;
 
         runtime·stdcall(runtime·GetSystemInfo, 1, &info);
         return info.dwNumberOfProcessors;
 }
 
 void
 runtime·osinit(void)
 {
-        uint8 randomdata[HashRandomBytes];
-        uintptr handle;
-
         // -1 = current process, -2 = current thread
         runtime·stdcall(runtime·DuplicateHandle, 7,
                 (uintptr)-1, (uintptr)-2, (uintptr)-1, &m->thread,
                 (uintptr)0, (uintptr)0, (uintptr)DUPLICATE_SAME_ACCESS);
         runtime·stdcall(runtime·SetConsoleCtrlHandler, 2, runtime·ctrlhandler, (uintptr)1);
         runtime·stdcall(runtime·timeBeginPeriod, 1, (uintptr)1);
         runtime·ncpu = getproccount();
-
-        runtime·memclr(randomdata, HashRandomBytes);
-        if (runtime·stdcall(runtime·CryptAcquireContextW, 5, &handle, nil, nil,
-                            (uintptr)1 /* PROV_RSA_FULL */,
-                            (uintptr)0xf0000000U /* CRYPT_VERIFYCONTEXT */) != 0) {
-                runtime·stdcall(runtime·CryptGenRandom, 3, handle, (uintptr)HashRandomBytes, randomdata);
+}
+
+void
+runtime·get_random_data(byte **rnd, int32 *rnd_len)
+{
+        uintptr handle;
+        *rnd = nil;
+        *rnd_len = 0;
+        if(runtime·stdcall(runtime·CryptAcquireContextW, 5, &handle, nil, nil,
+                           (uintptr)1 /* PROV_RSA_FULL */,
+                           (uintptr)0xf0000000U /* CRYPT_VERIFYCONTEXT */) != 0) {
+                static byte random_data[HashRandomBytes];
+                if(runtime·stdcall(runtime·CryptGenRandom, 3, handle, (uintptr)HashRandomBytes, random_data)) {
+                        *rnd = random_data;
+                        *rnd_len = HashRandomBytes;
+                }
                 runtime·stdcall(runtime·CryptReleaseContext, 2, handle, (uintptr)0);
         }
-        runtime·hashinit(randomdata);
 }
 
 void
 runtime·goenvs(void)
 {
         extern Slice syscall·envs;
 
         uint16 *env;
         String *s;
         int32 i, n;
@@ skipping 37 matching lines @@
                 handle = runtime·stdcall(runtime·GetStdHandle, 1, (uintptr)-11);
                 break;
         case 2:
                 handle = runtime·stdcall(runtime·GetStdHandle, 1, (uintptr)-12);
                 break;
         default:
                 return -1;
         }
         runtime·stdcall(runtime·WriteFile, 5, handle, buf, (uintptr)n, &written, (uintptr)0);
         return written;
-}
-
-#pragma textflag 7
-void
-runtime·osyield(void)
-{
-        runtime·stdcall(runtime·Sleep, 1, (uintptr)0);
-}
-
-void
-runtime·usleep(uint32 us)
-{
-        us /= 1000;
-        if(us == 0)
-                us = 1;
-        runtime·stdcall(runtime·Sleep, 1, (uintptr)us);
 }
 
 #define INFINITE ((uintptr)0xFFFFFFFF)
 
 int32
 runtime·semasleep(int64 ns)
 {
         uintptr ms;
 
         if(ns < 0)
@@ skipping 275 matching lines @@
 runtime·setprof(bool on)
 {
         USED(on);
 }
 
 int8 runtime·badcallbackmsg[] = "runtime: cgo callback on thread not created by Go.\n";
 int32 runtime·badcallbacklen = sizeof runtime·badcallbackmsg - 1;
 
 int8 runtime·badsignalmsg[] = "runtime: signal received on thread not created by Go.\n";
 int32 runtime·badsignallen = sizeof runtime·badsignalmsg - 1;