From 3d8238e1d572b3a66452f01b79981fcf19b0bdae Mon Sep 17 00:00:00 2001
From: yellows8 <yellows8@users.noreply.github.com>
Date: Sat, 30 Dec 2017 22:13:59 -0500
Subject: [PATCH] Append custom data to the end of NRO for storing assets.

---
 src/elf2nro.c | 100 +++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 98 insertions(+), 2 deletions(-)

diff --git a/src/elf2nro.c b/src/elf2nro.c
index 175697c..e637264 100644
--- a/src/elf2nro.c
+++ b/src/elf2nro.c
@@ -34,6 +34,19 @@ typedef struct {
     u8  Padding[0x20];
 } NroHeader;
 
+typedef struct {
+    u64 offset;
+    u64 size;
+} AssetSection;
+
+typedef struct {
+    u8  magic[4];
+    u32 version;
+    AssetSection icon;
+    AssetSection nacp;
+    AssetSection romfs;
+} AssetHeader;
+
 uint8_t* ReadEntireFile(const char* fn, size_t* len_out) {
     FILE* fd = fopen(fn, "rb");
     if (fd == NULL)
@@ -61,8 +74,12 @@ uint8_t* ReadEntireFile(const char* fn, size_t* len_out) {
 }
 
 int main(int argc, char* argv[]) {
-    if (argc != 3) {
-        fprintf(stderr, "%s <elf-file> <nro-file>\n", argv[0]);
+    if (argc < 3) {
+        fprintf(stderr, "%s <elf-file> <nro-file> [options]\n\n", argv[0]);
+        fprintf(stderr, "Options:\n");
+        fprintf(stderr, "--icon=<iconpath> Embeds icon into the output file.\n");
+        fprintf(stderr, "--nacp=<control.nacp> Embeds control.nacp into the output file.\n");
+        fprintf(stderr, "--romfs=<image> Embeds RomFS into the output file.\n");//TODO: Use directory for input instead.
         return EXIT_FAILURE;
     }
     
@@ -85,6 +102,14 @@ int main(int argc, char* argv[]) {
         return EXIT_FAILURE;
     }
 
+    int argi;
+    char* icon_path = NULL, *nacp_path = NULL, *romfs_path = NULL;
+    for (argi=3; argi<argc; argi++) {
+        if (strncmp(argv[argi], "--icon=", 7)==0) icon_path = &argv[argi][7];
+        if (strncmp(argv[argi], "--nacp=", 7)==0) nacp_path = &argv[argi][7];
+        if (strncmp(argv[argi], "--romfs=", 8)==0) romfs_path = &argv[argi][8];
+    }
+
     if (elf_len < sizeof(Elf64_Ehdr)) {
         fprintf(stderr, "Input file doesn't fit ELF header!\n");
         return EXIT_FAILURE;
@@ -167,5 +192,76 @@ int main(int argc, char* argv[]) {
     fseek(out, sizeof(nro_start), SEEK_SET);
     fwrite(&nro_hdr, sizeof(nro_hdr), 1, out);
 
+    if (icon_path==NULL && nacp_path==NULL && romfs_path==NULL) {
+        fclose(out);
+        return EXIT_SUCCESS;
+    }
+
+    AssetHeader asset_hdr;
+    memset(&asset_hdr, 0, sizeof(asset_hdr));
+    memcpy(asset_hdr.magic, "ASET", 4);
+    asset_hdr.version = 0;
+
+    fseek(out, file_off, SEEK_SET);
+
+    uint8_t* icon = NULL, *nacp = NULL, *romfs = NULL;
+    size_t icon_len = 0, nacp_len = 0, romfs_len = 0;
+    size_t tmp_off = sizeof(asset_hdr);
+
+    if (icon_path) {
+        icon = ReadEntireFile(icon_path, &icon_len);
+        if (icon == NULL) {
+            fprintf(stderr, "Failed to open input icon!\n");
+            return EXIT_FAILURE;
+        }
+
+        asset_hdr.icon.offset = tmp_off;
+        asset_hdr.icon.size = icon_len;
+        tmp_off+= icon_len;
+    }
+
+    if (nacp_path) {
+        nacp = ReadEntireFile(nacp_path, &nacp_len);
+        if (nacp == NULL) {
+            fprintf(stderr, "Failed to open input nacp!\n");
+            return EXIT_FAILURE;
+        }
+
+        asset_hdr.nacp.offset = tmp_off;
+        asset_hdr.nacp.size = nacp_len;
+        tmp_off+= nacp_len;
+    }
+
+    if (romfs_path) {
+        romfs = ReadEntireFile(romfs_path, &romfs_len);
+        if (romfs == NULL) {
+            fprintf(stderr, "Failed to open input romfs!\n");
+            return EXIT_FAILURE;
+        }
+
+        asset_hdr.romfs.offset = tmp_off;
+        asset_hdr.romfs.size = romfs_len;
+        tmp_off+= romfs_len;
+    }
+
+    fwrite(&asset_hdr, sizeof(asset_hdr), 1, out);
+
+    if (icon_path) {
+        fseek(out, file_off + asset_hdr.icon.offset, SEEK_SET);
+        fwrite(icon, icon_len, 1, out);
+    }
+
+    if (nacp_path) {
+        fseek(out, file_off + asset_hdr.nacp.offset, SEEK_SET);
+        fwrite(nacp, nacp_len, 1, out);
+    }
+
+    if (romfs_path) {
+        fseek(out, file_off + asset_hdr.romfs.offset, SEEK_SET);
+        fwrite(romfs, romfs_len, 1, out);
+    }
+
+    fclose(out);
+
     return EXIT_SUCCESS;
 }