lldb stub

lldb.c

//
//  LLDB Stub.
//
enum lldb_input_state {
    LLDB_INPUT_BEGIN,
    LLDB_INPUT_DATA,
    LLDB_INPUT_CHECKSUM1,
    LLDB_INPUT_CHECKSUM2,
};

static void lldb_process(const char *cmd) {
    DBG("lldb: < %s", cmd);
}

static bool lldb_input(char ch) {
    static char cmd[128];
    static char checksum[2];
    static int i = 0;
    static bool escaped = false;
    static char repeat = 0;
    static enum lldb_input_state state = LLDB_INPUT_BEGIN;

    // FIXME: overflow checks for `i`
    switch (state) {
        case LLDB_INPUT_BEGIN:
            i = 0;
            state = LLDB_INPUT_DATA;
            /* fallthrough */
        case LLDB_INPUT_DATA:
            if (escaped) {
                cmd[i] = ch ^ 0x20;
                i++;
                escaped = false;
            } else if (repeat) {
                for (int j = ch - 29; j > 0; j--) {
                    cmd[i] = repeat;
                    i++;
                }
                repeat = 0;
            }  else {
                switch (ch) {
                    // Repetition of the previous character.
                    case '*':
                        if (i > 0) {
                            repeat = cmd[i - 1];
                        }
                        break;
                    // Escaping character.
                    case '}':
                        escaped = true;
                        break;
                    default:
                        if (ch == '#') {
                            state = LLDB_INPUT_CHECKSUM1;
                        } else {
                            cmd[i] = ch;
                            i++;
                        }
                }
            }
            return true;
        case LLDB_INPUT_CHECKSUM1:
            checksum[0] = ch;
            state = LLDB_INPUT_CHECKSUM2;
            return true;
        case LLDB_INPUT_CHECKSUM2:
            checksum[1] = ch;
            state = LLDB_INPUT_BEGIN;
            break;
    }

    lldb_process(cmd);
    return false;
}

void kdebug_handle_interrupt(void) {
    static bool gdb_pkt = false;
    int ch;
    while ((ch = kdebug_readchar()) > 0) {
        if (gdb_pkt) {
            gdb_pkt = lldb_input(ch);
        } else if (ch == '$') {
            gdb_pkt = true;
        } else {
            input(ch);
        }
    }
}