Version 1.08 with public source code release.

src/main/util/patch.c

@@ -0,0 +1,59 @@
+#define LOG_MODULE "util-patch"
+
+#include <sys/mman.h>
+
+#include "util/log.h"
+#include "util/patch.h"
+
+/* addr needs to be a multiple of page size */
+#define UNPROTECT(addr,len) mprotect((void*)(addr-(addr%4096)),(addr%4096) + \
+    len,PROT_READ|PROT_WRITE|PROT_EXEC)
+
+void util_patch_write_memory(uintptr_t mem, const void* data, size_t len)
+{
+	if (UNPROTECT(mem, len) != 0) {
+		log_die("Unprotecting memory %p, len %d failed", mem, len);
+    }
+
+	memcpy((void*) mem, data, len);
+}
+
+void util_patch_write_memory_byte(uintptr_t mem, uint8_t data)
+{
+    util_patch_write_memory(mem, (const void*) &data, sizeof(uint8_t));
+}
+
+void util_patch_function(uintptr_t func_addr, void* detour_func)
+{
+	/* uintptr_t is said to be portable (32/64-bit) */
+	uint8_t offset = 5;
+
+    /* 64-bit binary */
+	if (sizeof(uintptr_t) == 8) {
+		offset += 4;
+    }
+
+	uintptr_t call = 
+        (uintptr_t) (((uintptr_t) detour_func) - func_addr - offset);
+	
+    if (UNPROTECT(func_addr, 4096) != 0) {
+		log_die("Unprotecting memory %p, len %d failed", func_addr);
+    }
+
+	*((uint8_t*) (func_addr)) = 0xE9;
+	*((uintptr_t*) (func_addr + 1)) = call;
+}
+
+void* util_patch_find_signiture(const uint8_t* sig, uint32_t sig_len, 
+    	int32_t sig_offset, void* start_addr, void* end_addr, int32_t alignment)
+{
+	size_t pos;
+	
+	for (pos = (size_t) start_addr; pos < (size_t) end_addr; pos += alignment) {
+		if (!memcmp((void*) pos, sig, sig_len)) {
+			return (void*) (pos + sig_offset);
+		}
+	}
+	
+	return NULL;	
+}