Implement NRO loader

app/CMakeLists.txt

@@ -6,5 +6,10 @@ set(source_DIR ${CMAKE_SOURCE_DIR}/src/main/cpp)
 
 include_directories(${source_DIR}/include)
 
-add_library(lightswitch SHARED ${source_DIR}/lightswitch.cpp ${source_DIR}/core/arm/cpu.cpp)
+add_library(lightswitch SHARED
+        ${source_DIR}/lightswitch.cpp
+        ${source_DIR}/core/arm/cpu.cpp
+
+        ${source_DIR}/core/hos/loaders/nro.cpp
+)
 target_link_libraries(lightswitch ${source_DIR}/lib/${ANDROID_ABI}/libunicorn.a)

app/src/main/cpp/core/hos/loaders/nro.cpp

@@ -0,0 +1,64 @@
+#include <fstream>
+#include <string>
+#include <syslog.h>
+#include <sys/mman.h>
+#include <vector>
+#include "nro.h"
+
+// TODO: Move memory to it's own file
+#define MEM_BASE 0x80000000
+
+void ReadDataFromFile(std::string file, char* output, uint32_t offset, size_t size)
+{
+    std::ifstream f(file, std::ios::binary | std::ios::beg);
+
+    f.seekg(offset);
+    f.read(output, size);
+
+    f.close();
+}
+
+namespace loader {
+    bool LoadNro(std::string file) {
+        syslog(LOG_INFO, "Loading NRO file %s\n", file.c_str());
+
+        NroHeader h;
+        ReadDataFromFile(file, reinterpret_cast<char *>(&h), 0x0, sizeof(NroHeader));
+        if (h.magic != 0x304F524E) {
+            syslog(LOG_ERR, "Invalid NRO magic 0x%x\n", h.magic);
+            return false;
+        }
+
+        std::vector<uint32_t> text, ro, data;
+        text.resize(h.segments[0].size);
+        ro.resize(h.segments[1].size);
+        data.resize(h.segments[2].size);
+
+        ReadDataFromFile(file, reinterpret_cast<char *>(text.data()),
+                                     h.segments[0].fileOffset, h.segments[0].size);
+        ReadDataFromFile(file, reinterpret_cast<char *>(ro.data()),
+                                     h.segments[1].fileOffset, h.segments[1].size);
+        ReadDataFromFile(file, reinterpret_cast<char *>(data.data()),
+                                     h.segments[2].fileOffset, h.segments[2].size);
+
+
+        if(!mmap((void*)(MEM_BASE),
+                 h.segments[0].size, PROT_EXEC | PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, 0, 0) ||
+           !mmap((void*)(MEM_BASE + h.segments[0].size),
+                 h.segments[1].size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, 0, 0) ||
+           !mmap((void*)(MEM_BASE + h.segments[0].size + h.segments[1].size),
+                 h.segments[2].size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, 0, 0) ||
+           !mmap((void*)(MEM_BASE + h.segments[0].size + h.segments[1].size + h.segments[2].size),
+                 h.bssSize, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, 0, 0)) {
+
+           syslog(LOG_ERR, "Failed mapping regions for executable");
+           return false;
+        }
+
+        std::memcpy((void*)(MEM_BASE), text.data(), text.size());
+        std::memcpy((void*)(MEM_BASE + h.segments[0].size), ro.data(), ro.size());
+        std::memcpy((void*)(MEM_BASE + h.segments[0].size + h.segments[1].size), data.data(), data.size());
+
+        return true;
+    }
+}

app/src/main/cpp/core/hos/loaders/nro.h

@@ -0,0 +1,31 @@
+#pragma once
+#include <cstdint>
+
+namespace loader {
+    struct NroSegmentHeader {
+        uint32_t fileOffset;
+        uint32_t size;
+    };
+
+    struct NroHeader {
+        uint32_t unused;
+        uint32_t modOffset;
+        uint64_t padding;
+
+        uint32_t magic;
+        uint32_t version;
+        uint32_t size;
+        uint32_t flags;
+
+        NroSegmentHeader segments[3];
+
+        uint32_t bssSize;
+        uint32_t reserved0;
+        uint64_t buildId[4];
+        uint64_t reserved1;
+
+        NroSegmentHeader extraSegments[3];
+    };
+
+    bool LoadNro(std::string file);
+}