X-Git-Url: https://git.saurik.com/apple/security.git/blobdiff_plain/72a12576750f52947eb043106ba5c12c0d07decf..b1ab9ed8d0e0f1c3b66d7daa8fd5564444c56195:/libsecurity_transform/lib/SecTransformReadTransform.cpp

diff --git a/libsecurity_transform/lib/SecTransformReadTransform.cpp b/libsecurity_transform/lib/SecTransformReadTransform.cpp
new file mode 100644
index 00000000..902bfb1d
--- /dev/null
+++ b/libsecurity_transform/lib/SecTransformReadTransform.cpp
@@ -0,0 +1,124 @@
+#include "SecTransformReadTransform.h"
+#include "SecCustomTransform.h"
+#include "Utilities.h"
+
+static CFStringRef kStreamTransformName = CFSTR("SecReadStreamTransform");
+static CFStringRef kStreamMaxSize = CFSTR("MAX_READSIZE");
+
+static SecTransformInstanceBlock StreamTransformImplementation(CFStringRef name,
+															   SecTransformRef newTransform,
+															   SecTransformImplementationRef ref)
+{
+	SecTransformInstanceBlock instanceBlock =
+	^{
+		CFErrorRef result = NULL;
+		
+		if (NULL == name || NULL == newTransform)
+		{
+		}
+		
+		// define the storage for our block
+		__block CFIndex blockSize = 4096;  // make a default block size
+		
+		// it's not necessary to set the input stream size
+		SecTransformCustomSetAttribute(ref, kStreamMaxSize, kSecTransformMetaAttributeRequired, kCFBooleanFalse);
+		
+		// define the action if we change the max read size
+		SecTransformSetAttributeAction(ref, kSecTransformActionAttributeNotification, kStreamMaxSize,
+		^(SecTransformAttributeRef attribute, CFTypeRef value)
+		{
+			CFNumberGetValue((CFNumberRef) value, kCFNumberCFIndexType, &blockSize);
+			return value;
+		});
+		
+		// define for our input action
+		SecTransformSetAttributeAction(ref, kSecTransformActionAttributeNotification, kSecTransformInputAttributeName,
+		^(SecTransformAttributeRef attribute, CFTypeRef value)
+		{
+			if (value == NULL)
+			{
+				return (CFTypeRef) NULL;
+			}
+			
+			CFArrayRef array = (CFArrayRef) value;
+			CFReadStreamRef input = (CFReadStreamRef) CFArrayGetValueAtIndex(array, 0);
+			
+			// open the stream
+			if (!CFReadStreamOpen(input))
+			{
+				// We didn't open properly.  Error out
+				return (CFTypeRef) CreateSecTransformErrorRef(kSecTransformErrorInvalidInput, "An error occurred while opening the stream.");
+			}
+			
+			// allocate the read buffer on the heap
+			u_int8_t* buffer = (u_int8_t*) malloc(blockSize);
+			
+			CFIndex bytesRead;
+			
+			bytesRead = CFReadStreamRead(input, buffer, blockSize);
+			while (bytesRead > 0)
+			{
+				// make data from what was read
+				CFDataRef value = CFDataCreate(NULL, buffer, bytesRead);
+				
+				// send it down the chain
+				SecTransformCustomSetAttribute(ref, kSecTransformOutputAttributeName, kSecTransformMetaAttributeValue, value);
+				
+				// cleanup
+				CFRelease(value);
+				
+				bytesRead = CFReadStreamRead(input, buffer, blockSize);
+			}
+			
+			free(buffer);
+			
+			SecTransformCustomSetAttribute(ref, kSecTransformOutputAttributeName, kSecTransformMetaAttributeValue, (CFTypeRef) NULL);
+			
+			return (CFTypeRef) NULL;
+		});
+		
+		return result;
+	};
+	
+	return Block_copy(instanceBlock);
+}
+
+
+
+SecTransformRef SecTransformCreateReadTransformWithReadStream(CFReadStreamRef inputStream)
+{
+	static dispatch_once_t once = 0;
+	
+	__block bool ok = true;
+	__block CFErrorRef result = NULL;
+	
+	dispatch_once(&once,
+	^{
+		ok = SecTransformRegister(kStreamTransformName, &StreamTransformImplementation, &result);
+	});
+	
+	if (!ok)
+	{
+		return result;
+	}
+	else
+	{
+	
+		SecTransformRef transform = SecTransformCreate(kStreamTransformName, &result);
+		if (NULL != transform)
+		{
+			// if we add the read stream directly to the transform the internal source stream
+			// will take over. This is bad.  Instead, we wrap this in a CFArray so that we can
+			// pass through undetected
+			CFTypeRef arrayData[] = {inputStream};
+			CFArrayRef arrayRef = CFArrayCreate(NULL, arrayData, 1, &kCFTypeArrayCallBacks);
+
+			// add the input to the transform
+			SecTransformSetAttribute(transform, kSecTransformInputAttributeName, arrayRef, &result);
+			
+			CFRelease(arrayRef);
+		}
+		
+		return transform;
+	}
+}