Difference between revisions of "NPDM"

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(Access descriptors...this is basically 3ds, but with type at bottom instead of top)
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The service string can contain a wildcard <code>*</code> character.
 
The service string can contain a wildcard <code>*</code> character.
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=Access Descriptors=
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Like the 3DS, the switch has a number of kernel capability descriptors. Unlike 3ds, where descriptors were identified by pattern 11..10 in high bits, on switch descriptors are identified by pattern 01..11 in low bits.
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{| class="wikitable" border="1"
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|-
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! Pattern of bits 20-31
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! Type
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! Fields
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|-
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| <code>0bxxxxxxxx0111?</code>
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| Interrupt info?
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| ?
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|-
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| <code>0bxxxxxxx01111</code>
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| System call mask
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| Bits 29-31: System call mask table index; Bits 5-28: mask
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|-
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| <code>0bxxxxx0111111?</code>
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| Kernel release version?
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| ?
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|-
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| <code>0bxxxx01111111?</code>
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| Handle table size?
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| ?
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|-
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| <code>0bxxx011111111?</code>
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| Kernel flags?
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| ?
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|-
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| <code>0bx0111111111?</code>
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| Map address range?
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| ?
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|-
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| <code>0b011111111111?</code>
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| Map memory page?
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| ?
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|}
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=FS Permissions=
 
=FS Permissions=

Revision as of 08:59, 28 June 2017

This is the Switch equivalent of 3DS exheader. This is the file with extension ".npdm" in {Switch ExeFS}. The size of this file varies.

Offset Size Description
0x0 0x80 META
0x80 0x200 RSA-2048 signature, followed a RSA-2048 modulus for NCA header (like 3DS)
0x280 <Varies> ACID
<See META> <See META> ACI0

META

Offset Size Description
0x0 0x4 Magicnum "META".
0x20 ? Name string
0x70 0x4 Absolute offset for ACI0.
0x74 0x4 Size of ACI0.
0x78 0x4 Absolute offset of the RSA signature.
0x7C 0x4 Size used with the above offset. Offset+size is normally ACI0_start-8.

Switch version of 3DS "System Control Info"?

ACID

Offset Size Description
0x0 0x4 Magicnum "ACID".
0x4 0x28 ?
0x2C 0x4 Size of the Service Access Control.
0x30 0x14 ?
0x44 ? FS Permissions
0xF0 <See above> Service Access Control

Switch version of AccessDesc?

ACI0

Offset Size Description
0x0 0x4 Magicnum "ACI0".
0x4 0x28 ?
0x2C 0x4 Size of the Service Access Control.
0x30 0x14 ?
0x44 ? FS Permissions
0x60 <See above> Service Access Control


Switch version of 3DS ACI(Access Control Info)?

Service Access Control

This is a list of service-name strings which the title has access to, with the following structure: 

 +0: control_byte
 +1: {service-name without nul-terminator}

Bitmask 0x0F in control_byte is the {length of the service-name without nul-terminator} - 1.

Bitmask 0x80 in control_byte means service is allowed to be registered.

The service string can contain a wildcard * character.

Access Descriptors

Like the 3DS, the switch has a number of kernel capability descriptors. Unlike 3ds, where descriptors were identified by pattern 11..10 in high bits, on switch descriptors are identified by pattern 01..11 in low bits.

Pattern of bits 20-31 Type Fields
0bxxxxxxxx0111? Interrupt info? ?
0bxxxxxxx01111 System call mask Bits 29-31: System call mask table index; Bits 5-28: mask
0bxxxxx0111111? Kernel release version? ?
0bxxxx01111111? Handle table size? ?
0bxxx011111111? Kernel flags? ?
0bx0111111111? Map address range? ?
0b011111111111? Map memory page? ?


FS Permissions

Bit Description
0 MountContent* is accessible when set.
3 This is only bit set for ShopN in the permissions-u32.
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