From 98f68dd9bb0318acfaaf7f2e7ad571a19729a8bb Mon Sep 17 00:00:00 2001
From: Adrian Kummerlaender
Date: Tue, 16 Feb 2016 23:55:40 +0100
Subject: Move actual function pointers to function local static variables

The previous approach of storing them in static variables of the `actual` namespace and initializing them statically did not work out as it is not guaranteed that they are initialized before any interposed function is called.
---
 src/actual.h | 46 +++++++++-------------------------------------
 1 file changed, 9 insertions(+), 37 deletions(-)

(limited to 'src/actual.h')

diff --git a/src/actual.h b/src/actual.h
index af64ec3..cb08d42 100644
--- a/src/actual.h
+++ b/src/actual.h
@@ -12,49 +12,21 @@
 #include <memory>
 #include <cstring>
 
-namespace {
-	template <class Result, typename... Arguments>
-	using function_ptr = Result(*)(Arguments...);
-
-	template <typename FunctionPtr>
-	FunctionPtr get_actual_function(const std::string& symbol_name) {
-		const void* symbol_address{ dlsym(RTLD_NEXT, symbol_name.c_str()) };
-
-		FunctionPtr actual_function{};
-		std::memcpy(&actual_function, &symbol_address, sizeof(symbol_address));
-
-		return actual_function;
-	}
-}
-
 namespace actual {
-	static auto write = get_actual_function<
-		function_ptr<ssize_t, int, const void*, size_t>
-	>("write");
-
-	static auto writev = get_actual_function<
-		function_ptr<ssize_t, int, const iovec*, int>
-	>("writev");
 
-	static auto rename = get_actual_function<
-		function_ptr<int, const char*, const char*>
-	>("rename");
+template <class Result, typename... Arguments>
+using ptr = Result(*)(Arguments...);
 
-	static auto rmdir = get_actual_function<
-		function_ptr<int, const char*>
-	>("rmdir");
+template <typename FunctionPtr>
+FunctionPtr get_ptr(const std::string& symbol_name) {
+	const void* symbol_address{ dlsym(RTLD_NEXT, symbol_name.c_str()) };
 
-	static auto unlink = get_actual_function<
-		function_ptr<int, const char*>
-	>("unlink");
+	FunctionPtr actual_function{};
+	std::memcpy(&actual_function, &symbol_address, sizeof(symbol_address));
 
-	static auto unlinkat = get_actual_function<
-		function_ptr<int, int, const char*, int>
-	>("unlinkat");
+	return actual_function;
+}
 
-	static auto mmap = get_actual_function<
-		function_ptr<void*, void*, size_t, int, int, int, off_t>
-	>("mmap");
 }
 
 #endif  // CHANGE_SRC_ACTUAL_FUNCTION_H_
-- 
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