IPC
Every RPC command sent to services starts with a u32 header code:
Bits | Description |
---|---|
0-5 | Number of translate parameters (=x) |
6-15 | Number of normal parameters (=y) |
16-31 | Command ID |
The entire command has the following structure:
Word | Size | Description |
---|---|---|
0 | 1 | Header code |
1 | x | Normal parameters |
x | y | Translate parameters |
Translate parameters are modified/translated transparently by the kernel. They are used to transfer handles/buffers between the different processes.
The type of parameter is described by the bits 1-3 in the translation descriptor. Parameter types accepted for sending by the kernel are: 0, 1, 2, 5, 6, 7. Type 0 is used to send handles across processes:
if desc & 0x30 == 0x20: write process id to value else: translate handle if desc & 0x30 == 0x10: close handle for caller
For replies, only 0, 1, 5, 6, 7 are allowed. In other words any type 2 fields must be zeroed before calling svcReplyAndReceive on the server-side. For replies type 0, 1, 2 are ignored. Types 5, 6, 7 do something with the mem pointer upon reply. The type 0 descriptor can be used to ignore parameters. The number of parameters covered by a type-0 descriptor is (desc >> 26) + 1.
Descriptor | Description |
---|---|
0x00000000 | The corresponding value is a KHandle, that should be closed in calling process. |
0x00000010 | The corresponding value is a KHandle, that will be shared/duplicated? |
0x00000020 | Let kernel set value to calling process ProcessID |
0x0000???2 | (size<<14) | The corresponding value contains a ptr to a buffer of said size. |
0x0000000A | (size<<4) | The corresponding value contains a ptr to a buffer of said size. |
0x0000000C | (size<<4) | The corresponding value contains a ptr to a buffer of said size. |