Difference between revisions of "NRO"

From Nintendo Switch Brew
Jump to navigation Jump to search
 
(One intermediate revision by the same user not shown)
Line 1: Line 1:
[[Category:File formats]]
 
 
NRO is the executable format for non-[[ExeFS]] binaries.
 
NRO is the executable format for non-[[ExeFS]] binaries.
  
 
It starts with the NRO-start structure then the "NRO" header and mainly describes .text, .rodata, and .data segments (like a short-form of ELF program headers):
 
It starts with the NRO-start structure then the "NRO" header and mainly describes .text, .rodata, and .data segments (like a short-form of ELF program headers):
  
= NRO Start =
+
= Start =
 
{| class="wikitable" border="1"
 
{| class="wikitable" border="1"
 
|-
 
|-
Line 24: Line 23:
 
|}
 
|}
  
= NRO Header =
+
= Header =
 
{| class="wikitable" border="1"
 
{| class="wikitable" border="1"
 
|-
 
|-
Line 37: Line 36:
 
| 0x4
 
| 0x4
 
| 0x4
 
| 0x4
| NRO Format Version (Always 0)
+
| Version (always 0)
 
|-
 
|-
 
| 0x8
 
| 0x8
 
| 4
 
| 4
| size (Total NRO filesize)
+
| Size (total NRO file size)
 
|-
 
|-
 
| 0xC
 
| 0xC
 
| 0x4
 
| 0x4
| Flags (Unused)
+
| Flags (unused)
 
|-
 
|-
 
| 0x10
 
| 0x10
 
| 0x8 * 3
 
| 0x8 * 3
| SegmentHeader[3] {.text, .ro, .data}
+
| [[#SegmentHeader|SegmentHeader]][3] {.text, .ro, .data}
 
|-
 
|-
 
| 0x28
 
| 0x28
 
| 0x4
 
| 0x4
| bssSize
+
| BssSize
 
|-
 
|-
 
| 0x2C
 
| 0x2C
 
| 0x4
 
| 0x4
| Reserved (Unused)
+
| Reserved
 
|-
 
|-
 
| 0x30
 
| 0x30
 
| 0x20
 
| 0x20
| Value of "build id" from ELF's GNU .note section. Contains variable sized digest, up to 32bytes.
+
| [[#ModuleId|ModuleId]]
 
|-
 
|-
 
| 0x50
 
| 0x50
| 0x08
+
| 0x04
| Reserved (Unused)
+
| DsoHandleOffset (unused)
 +
|-
 +
| 0x54
 +
| 0x04
 +
| Reserved (unused)
 
|-
 
|-
 
| 0x58
 
| 0x58
 
| 0x8 * 3
 
| 0x8 * 3
| SegmentHeader[3] {.apiInfo, .dynstr, .dynsym}
+
| [[#SegmentHeader|SegmentHeader]][3] {.apiInfo, .dynstr, .dynsym}
|-
 
 
|}
 
|}
  
Line 82: Line 84:
 
| 0x0
 
| 0x0
 
| 0x4
 
| 0x4
| FileOffset
+
| MemoryOffset
 
|-
 
|-
 
| 0x4
 
| 0x4
Line 89: Line 91:
 
|}
 
|}
  
=Assets=
+
== ModuleId ==
 +
Value of "build id" from ELF's GNU .note section. Contains variable sized digest, up to 32bytes.
 +
 
 +
= Assets =
 
This is an optional custom assets section for homebrew, this is located at file offset {NroHeader.size}. See also [https://github.com/switchbrew/switch-tools switch-tools] for implementation.
 
This is an optional custom assets section for homebrew, this is located at file offset {NroHeader.size}. See also [https://github.com/switchbrew/switch-tools switch-tools] for implementation.
  
Line 120: Line 125:
 
| 0x10
 
| 0x10
 
| AssetSection romfs. Can be used by the application.
 
| AssetSection romfs. Can be used by the application.
|-
 
 
|}
 
|}
  

Latest revision as of 17:37, 22 February 2020

NRO is the executable format for non-ExeFS binaries.

It starts with the NRO-start structure then the "NRO" header and mainly describes .text, .rodata, and .data segments (like a short-form of ELF program headers):

Start

Offset Size Description
0x0 0x4 Unused
0x4 0x4 MOD0 offset
0x8 0x8 Padding

Header

Offset Size Description
0x0 0x4 Magic "NRO0"
0x4 0x4 Version (always 0)
0x8 4 Size (total NRO file size)
0xC 0x4 Flags (unused)
0x10 0x8 * 3 SegmentHeader[3] {.text, .ro, .data}
0x28 0x4 BssSize
0x2C 0x4 Reserved
0x30 0x20 ModuleId
0x50 0x04 DsoHandleOffset (unused)
0x54 0x04 Reserved (unused)
0x58 0x8 * 3 SegmentHeader[3] {.apiInfo, .dynstr, .dynsym}

SegmentHeader

Offset Size Description
0x0 0x4 MemoryOffset
0x4 0x4 Size

ModuleId

Value of "build id" from ELF's GNU .note section. Contains variable sized digest, up to 32bytes.

Assets

This is an optional custom assets section for homebrew, this is located at file offset {NroHeader.size}. See also switch-tools for implementation.

The below offsets are relative to the beginning of the assets section (AssetHeader).

AssetHeader

Offset Size Description
0x0 0x4 Magic "ASET"
0x4 0x4 Format version, currently 0.
0x8 0x10 AssetSection icon. Used by the Homebrew Launcher. Like official icons, this is a 256x256 JPEG.
0x18 0x10 AssetSection NACP. Used by the Homebrew Launcher.
0x28 0x10 AssetSection romfs. Can be used by the application.

AssetSection

Offset Size Description
0x0 0x8 Offset
0x8 0x8 Size, 0 indicates this section is empty.