NSO: Difference between revisions
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NSO is the main executable format. | NSO is the main executable format. | ||
It starts with a | It starts with the "NSO" header and mainly describes .text, .rodata, and .data segments (like a short-form of ELF program headers): | ||
=== SegmentHeader === | |||
{| class="wikitable" border="1" | {| class="wikitable" border="1" | ||
|- | |- | ||
| Line 10: | Line 12: | ||
| 0x0 | | 0x0 | ||
| 4 | | 4 | ||
| | | file offset of data | ||
|- | |- | ||
| 0x4 | | 0x4 | ||
| 4 | | 4 | ||
| | | memory offset loaded to | ||
|- | |- | ||
| 0x8 | | 0x8 | ||
| 4 | | 4 | ||
| | | size of data copied to memory offset (i.e. size after decompression) | ||
|- | |- | ||
| 0xC | | 0xC | ||
| 4 | | 4 | ||
| | | alignment used on memory size / size of .bss in the case of .data segment | ||
|} | |||
=== .rodata-relative extent === | |||
{| class="wikitable" border="1" | |||
|- | |- | ||
! Offset | |||
! Size | |||
! Description | |||
|- | |- | ||
| | | 0x0 | ||
| 4 | | 4 | ||
| | | offset (relative to .rodata) | ||
|- | |- | ||
| | | 0x4 | ||
| 4 | | 4 | ||
| | | size of region | ||
|} | |||
=== NSO Header === | |||
{| class="wikitable" border="1" | |||
|- | |- | ||
! Offset | |||
! Size | |||
! Description | |||
|- | |- | ||
| | | 0x0 | ||
| 4 | | 4 | ||
| | | Magic "NSO0" | ||
|- | |- | ||
| | | 0x4 | ||
| 4 | | 4 | ||
| | | | ||
|- | |- | ||
| | | 0x8 | ||
| 4 | | 4 | ||
| | | | ||
|- | |- | ||
| | | 0xC | ||
| 4 | | 4 | ||
| | | | ||
|- | |- | ||
| | | 0x10 | ||
| | | 0x10 * 3 | ||
| | | SegmentHeader for each segment | ||
|- | |- | ||
| 0x40 | | 0x40 | ||
| 0x14 | | 0x14 | ||
| | | Value of "build id" from ELF's GNU .note section | ||
|- | |- | ||
| 0x54 | | 0x54 | ||
| Line 81: | Line 79: | ||
|- | |- | ||
| 0x60 | | 0x60 | ||
| | | 0x4 * 3 | ||
| . | | file size of each segment (i.e. LZ4-compressed size) | ||
|- | |||
| 0x6c | |||
| 0x24 | |||
| Padding | |||
|- | |||
| 0x90 | |||
| 8 | |||
| .rodata-relative extents of .dynstr | |||
|- | |||
| 0x98 | |||
| 8 | |||
| .rodata-relative extents of .dynsym | |||
|- | |- | ||
| 0xA0 | | 0xA0 | ||
| | | 0x20 * 3 | ||
| SHA256 hashes over the decompressed sections using the above byte-sizes: .text, .rodata, and .data. | | SHA256 hashes over the decompressed sections using the above byte-sizes: .text, .rodata, and .data. | ||
|- | |- | ||