Add SystemNative_LowLevelMonitor_TimedWait to System.Native (dotnet#4…

…7325)

* Add SystemNative_LowLevelMonitor_TimedWait to System.Native

* Undefine _XOPEN_SOURCE before pthread.h to fix CoreCLR MacOS build

* Rework pthread_condattr_setclock/CLOCK_MONOTONIC logic to support iOS

* Try redefining _XOPEN_SOURCE

* Fix header for pthread_condattr_setclock check

* Copy check from CoreCLR GC

src/libraries/Common/src/Interop/Unix/System.Native/Interop.LowLevelMonitor.cs

@@ -23,6 +23,9 @@ internal static partial class Sys
         [DllImport(Libraries.SystemNative, EntryPoint = "SystemNative_LowLevelMonitor_Wait")]
         internal static extern void LowLevelMonitor_Wait(IntPtr monitor);
 
+        [DllImport(Libraries.SystemNative, EntryPoint = "SystemNative_LowLevelMonitor_TimedWait")]
+        internal static extern bool LowLevelMonitor_TimedWait(IntPtr monitor, int timeoutMilliseconds);
+
         [DllImport(Libraries.SystemNative, EntryPoint = "SystemNative_LowLevelMonitor_Signal_Release")]
         internal static extern void LowLevelMonitor_Signal_Release(IntPtr monitor);
     }

src/libraries/Native/Unix/Common/pal_config.h.in

@@ -88,6 +88,7 @@
 #cmakedefine01 HAVE_CLOCK_MONOTONIC
 #cmakedefine01 HAVE_CLOCK_REALTIME
 #cmakedefine01 HAVE_CLOCK_GETTIME_NSEC_NP
+#cmakedefine01 HAVE_PTHREAD_CONDATTR_SETCLOCK
 #cmakedefine01 HAVE_TCP_H_TCPSTATE_ENUM
 #cmakedefine01 HAVE_TCP_FSM_H
 #cmakedefine01 HAVE_GSSFW_HEADERS

src/libraries/Native/Unix/System.Native/entrypoints.c

@@ -223,6 +223,7 @@ static const Entry s_sysNative[] =
     DllImportEntry(SystemNative_LowLevelMonitor_Acquire)
     DllImportEntry(SystemNative_LowLevelMonitor_Release)
     DllImportEntry(SystemNative_LowLevelMonitor_Wait)
+    DllImportEntry(SystemNative_LowLevelMonitor_TimedWait)
     DllImportEntry(SystemNative_LowLevelMonitor_Signal_Release)
     DllImportEntry(SystemNative_UTimensat)
     DllImportEntry(SystemNative_GetTimestamp)

src/libraries/Native/Unix/System.Native/pal_threading.c

@@ -1,15 +1,25 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+#include "pal_config.h"
 #include "pal_threading.h"
 
 #include <limits.h>
 #include <sched.h>
 #include <assert.h>
 #include <stdbool.h>
 #include <stdlib.h>
+#include <errno.h>
+#include <time.h>
 
+#if defined(TARGET_OSX)
+// So we can use the declaration of pthread_cond_timedwait_relative_np
+#undef _XOPEN_SOURCE
+#endif
 #include <pthread.h>
+#if defined(TARGET_OSX)
+#define _XOPEN_SOURCE
+#endif
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 // LowLevelMonitor - Represents a non-recursive mutex and condition
@@ -51,20 +61,46 @@ LowLevelMonitor* SystemNative_LowLevelMonitor_Create()
         return NULL;
     }
 
-    error = pthread_cond_init(&monitor->Condition, NULL);
+#if HAVE_PTHREAD_CONDATTR_SETCLOCK && HAVE_CLOCK_MONOTONIC
+    pthread_condattr_t conditionAttributes;
+    error = pthread_condattr_init(&conditionAttributes);
     if (error != 0)
     {
-        error = pthread_mutex_destroy(&monitor->Mutex);
+        goto mutex_destroy;
+    }
+
+    error = pthread_condattr_setclock(&conditionAttributes, CLOCK_MONOTONIC);
+    if (error != 0)
+    {
+        error = pthread_condattr_destroy(&conditionAttributes);
         assert(error == 0);
-        free(monitor);
-        return NULL;
+        goto mutex_destroy;
+    }
+
+    error = pthread_cond_init(&monitor->Condition, &conditionAttributes);
+
+    int condAttrDestroyError = pthread_condattr_destroy(&conditionAttributes);
+    assert(condAttrDestroyError == 0);
+    (void)condAttrDestroyError; // unused in release build
+#else
+    error = pthread_cond_init(&monitor->Condition, NULL);
+#endif
+    if (error != 0)
+    {
+        goto mutex_destroy;
     }
 
 #ifdef DEBUG
     monitor->IsLocked = false;
 #endif
 
     return monitor;
+
+mutex_destroy:
+    error = pthread_mutex_destroy(&monitor->Mutex);
+    assert(error == 0);
+    free(monitor);
+    return NULL;
 }
 
 void SystemNative_LowLevelMonitor_Destroy(LowLevelMonitor* monitor)
@@ -119,6 +155,36 @@ void SystemNative_LowLevelMonitor_Wait(LowLevelMonitor* monitor)
     SetIsLocked(monitor, true);
 }
 
+int32_t SystemNative_LowLevelMonitor_TimedWait(LowLevelMonitor *monitor, int32_t timeoutMilliseconds)
+{
+    assert(timeoutMilliseconds >= 0);
+
+    SetIsLocked(monitor, false);
+
+    int error;
+
+    // Calculate the time at which a timeout should occur, and wait. Older versions of OSX don't support clock_gettime with
+    // CLOCK_MONOTONIC, so we instead compute the relative timeout duration, and use a relative variant of the timed wait.
+    struct timespec timeoutTimeSpec;
+#if HAVE_CLOCK_GETTIME_NSEC_NP
+    timeoutTimeSpec.tv_sec = timeoutMilliseconds / 1000;
+    timeoutTimeSpec.tv_nsec = (timeoutMilliseconds % 1000) * 1000 * 1000;
+    error = pthread_cond_timedwait_relative_np(&monitor->Condition, &monitor->Mutex, &timeoutTimeSpec);
+#else
+    error = clock_gettime(CLOCK_MONOTONIC, &timeoutTimeSpec);
+    assert(error == 0);
+    uint64_t nanoseconds = (uint64_t)timeoutMilliseconds * 1000 * 1000 + (uint64_t)timeoutTimeSpec.tv_nsec;
+    timeoutTimeSpec.tv_sec += nanoseconds / (1000 * 1000 * 1000);
+    timeoutTimeSpec.tv_nsec = nanoseconds % (1000 * 1000 * 1000);
+    error = pthread_cond_timedwait(&monitor->Condition, &monitor->Mutex, &timeoutTimeSpec);
+#endif
+    assert(error == 0 || error == ETIMEDOUT);
+
+    SetIsLocked(monitor, true);
+
+    return error == 0;
+}
+
 void SystemNative_LowLevelMonitor_Signal_Release(LowLevelMonitor* monitor)
 {
     assert(monitor != NULL);

src/libraries/Native/Unix/System.Native/pal_threading.h

@@ -18,4 +18,6 @@ PALEXPORT void SystemNative_LowLevelMonitor_Release(LowLevelMonitor* monitor);
 
 PALEXPORT void SystemNative_LowLevelMonitor_Wait(LowLevelMonitor* monitor);
 
+PALEXPORT int32_t SystemNative_LowLevelMonitor_TimedWait(LowLevelMonitor *monitor, int32_t timeoutMilliseconds);
+
 PALEXPORT void SystemNative_LowLevelMonitor_Signal_Release(LowLevelMonitor* monitor);

src/libraries/Native/Unix/configure.cmake

@@ -7,6 +7,7 @@ include(CheckStructHasMember)
 include(CheckSymbolExists)
 include(CheckTypeSize)
 include(CMakePushCheckState)
+include(CheckLibraryExists)
 
 # CMP0075 Include file check macros honor CMAKE_REQUIRED_LIBRARIES.
 if(POLICY CMP0075)
@@ -587,6 +588,8 @@ check_symbol_exists(
     time.h
     HAVE_CLOCK_GETTIME_NSEC_NP)
 
+check_library_exists(pthread pthread_condattr_setclock "" HAVE_PTHREAD_CONDATTR_SETCLOCK)
+
 check_symbol_exists(
     futimes
     sys/time.h