fix: removed limitation of read requests to 4KByte (violates libfuse API)

lib/webfuse/impl/operation/read.c

@@ -10,7 +10,8 @@
 #include "webfuse/impl/util/base64.h"
 #include "webfuse/impl/util/json_util.h"
 
-#define WF_MAX_READ_LENGTH 4096
+// do not read chunks larger than 1 MByte
+#define WF_MAX_READ_LENGTH (1024 * 1024)
 
 char * wf_impl_fill_buffer(
 	char const * data,
@@ -114,12 +115,16 @@ void wf_impl_operation_read(
     struct wf_impl_operation_context * user_data = fuse_req_userdata(request);
     struct wf_jsonrpc_proxy * rpc = wf_impl_operation_context_get_proxy(user_data);
 
-	if (NULL != rpc)
+	if ((NULL != rpc) && (size <= WF_MAX_READ_LENGTH))
 	{
-		int const length = (size <= WF_MAX_READ_LENGTH) ? (int) size : WF_MAX_READ_LENGTH;
+		int const length = (int) size;
 		int handle = (file_info->fh & INT_MAX);
 		wf_impl_jsonrpc_proxy_invoke(rpc, &wf_impl_operation_read_finished, request, "read", "siiii", user_data->name, (int) inode, handle, (int) offset, length);
 	}
+	else if (size > WF_MAX_READ_LENGTH)
+	{
+		fuse_reply_err(request, ENOMEM);
+	}
 	else
 	{
 		fuse_reply_err(request, ENOENT);

test/webfuse/operation/test_read.cc

@@ -39,7 +39,7 @@ TEST(wf_impl_operation_read, invoke_proxy)
 TEST(wf_impl_operation_read, invoke_proxy_limit_size)
 {
     MockJsonRpcProxy proxy;
-    EXPECT_CALL(proxy, wf_impl_jsonrpc_proxy_vinvoke(_,_,_,StrEq("read"),StrEq("siiii"))).Times(1);
+    EXPECT_CALL(proxy, wf_impl_jsonrpc_proxy_vinvoke(_,_,_,StrEq("read"),StrEq("siiii"))).Times(0);
 
     MockOperationContext context;
     EXPECT_CALL(context, wf_impl_operation_context_get_proxy(_)).Times(1)
@@ -49,6 +49,7 @@ TEST(wf_impl_operation_read, invoke_proxy_limit_size)
     op_context.name = nullptr;
     FuseMock fuse;
     EXPECT_CALL(fuse, fuse_req_userdata(_)).Times(1).WillOnce(Return(&op_context));
+    EXPECT_CALL(fuse, fuse_reply_err(_,_)).Times(1);
 
     fuse_req_t request = nullptr;
     fuse_ino_t inode = 1;

test/webfuse/test_server.cc

@@ -382,11 +382,11 @@ TEST(server, read_large_file)
     MockInvokationHander handler;
     EXPECT_CALL(handler, Invoke(StrEq("lookup"), _)).Times(AnyNumber());
     EXPECT_CALL(handler, Invoke(StrEq("lookup"), Lookup(1, "a.file"))).Times(1)
-        .WillOnce(Return("{\"inode\": 2, \"mode\": 420, \"type\": \"file\", \"size\": 1024000}"));
+        .WillOnce(Return("{\"inode\": 2, \"mode\": 420, \"type\": \"file\", \"size\": 102400}"));
     EXPECT_CALL(handler, Invoke(StrEq("getattr"), GetAttr(1))).Times(AnyNumber())
         .WillRepeatedly(Return("{\"mode\": 420, \"type\": \"dir\"}"));
     EXPECT_CALL(handler, Invoke(StrEq("getattr"), GetAttr(2))).Times(AnyNumber())
-        .WillRepeatedly(Return("{\"mode\": 420, \"type\": \"file\", \"size\": 1024000}"));
+        .WillRepeatedly(Return("{\"mode\": 420, \"type\": \"file\", \"size\": 102400}"));
     EXPECT_CALL(handler, Invoke(StrEq("open"), Open(2))).Times(1)
         .WillOnce(Return("{\"handle\": 42}"));
     EXPECT_CALL(handler, Invoke(StrEq("read"), _)).Times(AnyNumber())
@@ -394,7 +394,7 @@ TEST(server, read_large_file)
             int offset = json_integer_value(json_array_get(params, 3));
             int length = json_integer_value(json_array_get(params, 4));
 
-            int remaining = (offset < 1024000) ? 1024000 - offset : 0;
+            int remaining = (offset < 102400) ? 102400 - offset : 0;
             int count = (length < remaining) ? length : remaining;
 
             std::string data = std::string(count, '*');