Mac PrjFSLib: Use IOSharedDataQueue workaround library if available

This allows PrjFSLib and the prjfs-log tool to use alternate versions of the IODataQueueDequeue() and IODataQueuePeek() functions from a dylib on OS versions where the built-in functions are buggy. On affected versions, a library "libSharedDataQueue.dylib" is loaded if available, and its implementations of the aforementioned functions are used for the message and kext logging queues instead of the ones supplied by the OS's IOKit.framework.
microsoft · Oct 27, 2018 · c7e221b · c7e221b
1 parent b471dd4
commit c7e221b
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Showing 4 changed files with 117 additions and 5 deletions.
diff --git a/ProjFS.Mac/PrjFSLib/PrjFSLib.cpp b/ProjFS.Mac/PrjFSLib/PrjFSLib.cpp
@@ -215,7 +215,7 @@ PrjFS_Result PrjFS_StartVirtualizationInstance(
 
         while (1)
         {
-            IODataQueueEntry* entry = IODataQueuePeek(dataQueue.queueMemory);
+            IODataQueueEntry* entry = DataQueue_Peek(dataQueue.queueMemory);
             if (nullptr == entry)
             {
                 // No more items in queue
@@ -226,13 +226,13 @@ PrjFS_Result PrjFS_StartVirtualizationInstance(
             if (messageSize < sizeof(Message))
             {
                 cerr << "Bad message size: got " << messageSize << " bytes, expected minimum of " << sizeof(Message) << ", skipping. Kernel/user version mismatch?\n";
-                IODataQueueDequeue(dataQueue.queueMemory, nullptr, nullptr);
+                DataQueue_Dequeue(dataQueue.queueMemory, nullptr, nullptr);
                 continue;
             }
 
             void* messageMemory = malloc(messageSize);
             uint32_t dequeuedSize = messageSize;
-            IOReturn result = IODataQueueDequeue(dataQueue.queueMemory, messageMemory, &dequeuedSize);
+            IOReturn result = DataQueue_Dequeue(dataQueue.queueMemory, messageMemory, &dequeuedSize);
             if (kIOReturnSuccess != result || dequeuedSize != messageSize)
             {
                 cerr << "Unexpected result dequeueing message - result 0x" << hex << result << " dequeued " << dequeuedSize << "/" << messageSize << " bytes\n";

diff --git a/ProjFS.Mac/PrjFSLib/PrjFSUser.cpp b/ProjFS.Mac/PrjFSLib/PrjFSUser.cpp
@@ -3,6 +3,20 @@
 #include <IOKit/IOKitLib.h>
 #include <iostream>
 #include <mach/mach_port.h>
+#include <sys/utsname.h>
+#include <dlfcn.h>
+
+struct DarwinVersion
+{
+    unsigned long major, minor, revision;
+};
+
+typedef decltype(IODataQueueDequeue)* ioDataQueueDequeueFunctionPtr;
+static ioDataQueueDequeueFunctionPtr ioDataQueueDequeueFunction = nullptr;
+typedef decltype(IODataQueuePeek)* ioDataQueuePeekFunctionPtr;
+static ioDataQueuePeekFunctionPtr ioDataQueuePeekFunction = nullptr;
+
+static void InitDataQueueFunctions();
 
 
 io_connect_t PrjFSService_ConnectToDriver(enum PrjFSServiceUserClientType clientType)
@@ -122,3 +136,98 @@ bool PrjFSService_DataQueueInit(
     return false;
 }
 
+IOReturn DataQueue_Dequeue(IODataQueueMemory* dataQueue, void* data, uint32_t* dataSize)
+{
+    if (nullptr == ioDataQueueDequeueFunction)
+    {
+        InitDataQueueFunctions();
+    }
+    return ioDataQueueDequeueFunction(dataQueue, data, dataSize);
+}
+
+IODataQueueEntry* DataQueue_Peek(IODataQueueMemory* dataQueue)
+{
+    if (nullptr == ioDataQueuePeekFunction)
+    {
+        InitDataQueueFunctions();
+    }
+    return ioDataQueuePeekFunction(dataQueue);
+}
+
+
+static bool GetDarwinVersion(DarwinVersion& outVersion)
+{
+    utsname unameInfo = {};
+    if (0 != uname(&unameInfo))
+    {
+        return false;
+    }
+
+    char* fieldEnd = nullptr;
+    unsigned long majorVersion = strtoul(unameInfo.release, &fieldEnd, 10);
+    if (nullptr == fieldEnd || *fieldEnd != '.')
+    {
+        return false;
+    }
+
+    unsigned long minorVersion = strtoul(fieldEnd + 1, &fieldEnd, 10);
+    if (nullptr == fieldEnd || (*fieldEnd != '.' && *fieldEnd != '\0'))
+    {
+        return false;
+    }
+
+    outVersion.major = majorVersion;
+    outVersion.minor = minorVersion;
+    outVersion.revision = 0;
+
+    if (*fieldEnd != '\0')
+    {
+        unsigned long revision = strtoul(fieldEnd + 1, &fieldEnd, 10);
+        if (nullptr == fieldEnd || (*fieldEnd != '.' && *fieldEnd != '\0'))
+        {
+            return false;
+        }
+        outVersion.revision = revision;
+    }
+
+    return true;
+}
+
+static void InitDataQueueFunctions()
+{
+    ioDataQueueDequeueFunction = &IODataQueueDequeue;
+    ioDataQueuePeekFunction = &IODataQueuePeek;
+
+    DarwinVersion osVersion = {};
+    if (!GetDarwinVersion(osVersion))
+    {
+        return;
+    }
+
+    if ((osVersion.major == 17 && osVersion.minor >= 7) // macOS 10.13.6+
+        || (osVersion.major == 18 && osVersion.minor == 0)) // macOS 10.14(.0) exactly
+    {
+        void* dataQueueLibrary = dlopen("libSharedDataQueue.dylib", RTLD_LAZY);
+        if (nullptr == dataQueueLibrary)
+        {
+            fprintf(stderr, "Error opening data queue client library: %s\n", dlerror());
+        }
+        else
+        {
+            void* sym = dlsym(dataQueueLibrary, "IODataQueueDequeue");
+            if (nullptr != sym)
+            {
+                ioDataQueueDequeueFunction = reinterpret_cast<ioDataQueueDequeueFunctionPtr>(sym);
+            }
+
+            sym = dlsym(dataQueueLibrary, "IODataQueuePeek");
+            if (nullptr != sym)
+            {
+                ioDataQueuePeekFunction = reinterpret_cast<ioDataQueuePeekFunctionPtr>(sym);
+            }
+
+            // Allow the dataQueueLibrary handle to leak; if we called dlclose(),
+            // the library would be unloaded, breaking our function pointers.
+        }
+    }
+}
diff --git a/ProjFS.Mac/PrjFSLib/PrjFSUser.hpp b/ProjFS.Mac/PrjFSLib/PrjFSUser.hpp
@@ -23,3 +23,6 @@ bool PrjFSService_DataQueueInit(
     uint32_t clientPortType,
     uint32_t clientMemoryType,
     dispatch_queue_t eventHandlingQueue);
+
+IODataQueueEntry* DataQueue_Peek(IODataQueueMemory* dataQueue);
+IOReturn DataQueue_Dequeue(IODataQueueMemory* dataQueue, void* data, uint32_t* dataSize);
diff --git a/ProjFS.Mac/PrjFSLib/prjfs-log/prjfs-log.cpp b/ProjFS.Mac/PrjFSLib/prjfs-log/prjfs-log.cpp
@@ -44,7 +44,7 @@ int main(int argc, const char * argv[])
 
         while(true)
         {
-            IODataQueueEntry* entry = IODataQueuePeek(dataQueue.queueMemory);
+            IODataQueueEntry* entry = DataQueue_Peek(dataQueue.queueMemory);
             if(entry == nullptr)
             {
                 break;
@@ -65,7 +65,7 @@ int main(int argc, const char * argv[])
                 lineCount++;
             }
 
-            IODataQueueDequeue(dataQueue.queueMemory, nullptr, nullptr);
+            DataQueue_Dequeue(dataQueue.queueMemory, nullptr, nullptr);
         }
     });
     dispatch_resume(dataQueue.dispatchSource);