Aliceserver

Debugger server supporting the DAP protocol using Alicedbg.

Major work in progress! Don't expect it to replace GDB or LLDB.

Implementation Details

DAP

The Debugger Adapter Protocol leaves a lot of nuance regarding implementation details, which can be a little infuriating to work with.

This chapter reuses terminology from DAP, such as Integer meaning, strictly speaking, a 32-bit integer number (int), and Number meaning a 64-bit double-precision floating-point number (double, IEEE 754).

Connection

By default, single-session mode is used, where standard streams are used to communicate with the client (tool).

In single-session mode, the server starts by reading a line from the program's standard input stream ("stdin") by reading characters until a newline is seen, then reads an empty line.

This is used to get the (currently only) HTTP-like header field, Content-Length, describing the size of the HTTP body. Then, the server reads N amount of bytes described by the Content-Length field as an Integer.

A typical message may look like this:

Content-Length: 82\r\n
\r\n
{"seq":1,"type":"request","command":"initialize","arguments":{"adapterId":22"test"}}

Both client and server maintain their own sequence number, starting at 1.

NOTE: lldb-vscode starts their seq number at 0.

Multi-session mode is not currently supported.

Requests

Implementation-specific details:

• launch request:
  • arguments:path: (Required) [String] File path.
• attach request:
  • arguments:pid: (Required) [Integer] Process ID.

Command support:

Events

MI

The Machine Interface protocol is currently not supported, but could be in some future.

Licensing

This project is licensed under the BSD-3-Clause-Clear license.