gdb-server/server.c

#include <server.h>
#include <signal.h>
#include <stdio.h>

const char* REGISTERS[] = {
    "name:r0;bitsize:32;offset:0;encoding:uint;format:hex;set:General Purpose Registers;dwarf:0",
    "name:r1;bitsize:32;offset:4;encoding:uint;format:hex;set:General Purpose Registers;dwarf:1",
    "name:fp;alt-name:r2;bitsize:32;offset:8;encoding:uint;format:hex;set:General Purpose Registers;dwarf:2;generic:fp",
    "name:sp;alt-name:r3;bitsize:32;offset:12;encoding:uint;format:hex;set:General Purpose Registers;dwarf:3;generic:sp",
    "name:gp;alt-name:r4;bitsize:32;offset:16;encoding:uint;format:hex;set:General Purpose Registers;dwarf:4",
    "name:tp;alt-name:r5;bitsize:32;offset:20;encoding:uint;format:hex;set:General Purpose Registers;dwarf:5",
    "name:r6;bitsize:32;offset:24;encoding:uint;format:hex;set:General Purpose Registers;dwarf:6;generic:arg1",
    "name:r7;bitsize:32;offset:28;encoding:uint;format:hex;set:General Purpose Registers;dwarf:7;generic:arg2",
    "name:r8;bitsize:32;offset:32;encoding:uint;format:hex;set:General Purpose Registers;dwarf:8;generic:arg3",
    "name:r9;bitsize:32;offset:36;encoding:uint;format:hex;set:General Purpose Registers;dwarf:9;generic:arg4",
    "name:r10;bitsize:32;offset:40;encoding:uint;format:hex;set:General Purpose Registers;dwarf:10",
    "name:r11;bitsize:32;offset:44;encoding:uint;format:hex;set:General Purpose Registers;dwarf:11",
    "name:r12;bitsize:32;offset:48;encoding:uint;format:hex;set:General Purpose Registers;dwarf:12",
    "name:r13;bitsize:32;offset:52;encoding:uint;format:hex;set:General Purpose Registers;dwarf:13",
    "name:r14;bitsize:32;offset:56;encoding:uint;format:hex;set:General Purpose Registers;dwarf:14",
    "name:r15;bitsize:32;offset:60;encoding:uint;format:hex;set:General Purpose Registers;dwarf:15",
    "name:r16;bitsize:32;offset:64;encoding:uint;format:hex;set:General Purpose Registers;dwarf:16",
    "name:r17;bitsize:32;offset:68;encoding:uint;format:hex;set:General Purpose Registers;dwarf:17",
    "name:r18;bitsize:32;offset:72;encoding:uint;format:hex;set:General Purpose Registers;dwarf:18",
    "name:r19;bitsize:32;offset:76;encoding:uint;format:hex;set:General Purpose Registers;dwarf:19",
    "name:r20;bitsize:32;offset:80;encoding:uint;format:hex;set:General Purpose Registers;dwarf:20",
    "name:r21;bitsize:32;offset:84;encoding:uint;format:hex;set:General Purpose Registers;dwarf:21",
    "name:r22;bitsize:32;offset:88;encoding:uint;format:hex;set:General Purpose Registers;dwarf:22",
    "name:r23;bitsize:32;offset:92;encoding:uint;format:hex;set:General Purpose Registers;dwarf:23",
    "name:r24;bitsize:32;offset:96;encoding:uint;format:hex;set:General Purpose Registers;dwarf:24",
    "name:r25;bitsize:32;offset:100;encoding:uint;format:hex;set:General Purpose Registers;dwarf:25",
    "name:r26;bitsize:32;offset:104;encoding:uint;format:hex;set:General Purpose Registers;dwarf:26",
    "name:r27;bitsize:32;offset:108;encoding:uint;format:hex;set:General Purpose Registers;dwarf:27",
    "name:r28;bitsize:32;offset:112;encoding:uint;format:hex;set:General Purpose Registers;dwarf:28",
    "name:r29;bitsize:32;offset:116;encoding:uint;format:hex;set:General Purpose Registers;dwarf:29",
    "name:r30;bitsize:32;offset:120;encoding:uint;format:hex;set:General Purpose Registers;dwarf:30",
    "name:lp;alt-name:r31;bitsize:32;offset:124;encoding:uint;format:hex;set:General Purpose Registers;dwarf:31;generic:ra",
    "name:eipc;alt-name:sr0;bitsize:32;offset:128;encoding:uint;format:hex;set:Special Registers;dwarf:32",
    "name:eipsw;alt-name:sr1;bitsize:32;offset:132;encoding:uint;format:hex;set:Special Registers;dwarf:33",
    "name:fepc;alt-name:sr2;bitsize:32;offset:136;encoding:uint;format:hex;set:Special Registers;dwarf:34",
    "name:fepsw;alt-name:sr3;bitsize:32;offset:140;encoding:uint;format:hex;set:Special Registers;dwarf:35",
    "name:ecr;alt-name:sr4;bitsize:32;offset:144;encoding:uint;format:hex;set:Special Registers;dwarf:36",
    "name:psw;alt-name:sr5;bitsize:32;offset:148;encoding:uint;format:hex;set:Special Registers;dwarf:37;generic:flags",
    "name:pir;alt-name:sr6;bitsize:32;offset:152;encoding:uint;format:hex;set:Special Registers;dwarf:38",
    "name:tkcw;alt-name:sr7;bitsize:32;offset:156;encoding:uint;format:hex;set:Special Registers;dwarf:39",
    "name:chcw;alt-name:sr24;bitsize:32;offset:160;encoding:uint;format:hex;set:Special Registers;dwarf:40",
    "name:adtre;alt-name:sr25;bitsize:32;offset:164;encoding:uint;format:hex;set:Special Registers;dwarf:41",
    "name:sr29;bitsize:32;offset:168;encoding:uint;format:hex;set:Special Registers;dwarf:42",
    "name:sr30;bitsize:32;offset:172;encoding:uint;format:hex;set:Special Registers;dwarf:43",
    "name:sr31;bitsize:32;offset:176;encoding:uint;format:hex;set:Special Registers;dwarf:44",
    "name:pc;bitsize:32;offset:180;encoding:uint;format:hex;set:Special Registers;dwarf:45;generic:pc",
};

const uint32_t SYSTEM_REGISTERS[] = {
    VB_EIPC,
    VB_EIPSW,
    VB_FEPC,
    VB_FEPSW,
    VB_ECR,
    VB_PSW,
    VB_PIR,
    VB_TKCW,
    VB_CHCW,
    VB_ADTRE,
    29,
    30,
    31,
};

const uint32_t PC_INDEX = 32 + 13;

int handle_command(RdbResponse *res, CommandBuf *cmd, VB *sim, bool *running) {
    rdb_response_begin_packet(res);

    if (cmd_match_str(cmd, "QStartNoAckMode")) {
        /* The debugger is asking us to no longer ACK messages. */
        /* Note that we ack THIS response, because we already called rdb_response_begin_packet. */
        res->should_ack = false;
        rdb_response_write_str(res, "OK");
        return rdb_response_send_packet(res);
    }
    if (cmd_match_str(cmd, "qSupported")) {
        /* The debugger is asking for a list of features we support. */
        rdb_response_write_str(res, "no-resumed+;multiprocess;vContSupported;QNonStop+");
        return rdb_response_send_packet(res);
    }
    if (cmd_match_str(cmd, "QThreadSuffixSupported")) {
        /* The debugger is asking us to include the current thread as a suffix to some responses. */
        rdb_response_write_str(res, "OK");
        return rdb_response_send_packet(res);
    }
    if (cmd_match_str(cmd, "QListThreadsInStopReply")) {
        /* The debugger is asking us to list all threads whenever we stop running. */
        rdb_response_write_str(res, "OK");
        return rdb_response_send_packet(res);
    }
    if (cmd_match_str(cmd, "qHostInfo")) {
        /* The debugger is asking us to describe the "host machine" getting debugged. */
        rdb_response_write_str(res, "triple:");
        rdb_response_write_str_hex(res, "v810-unknown-vb");
        rdb_response_write_str(res, ";endian:little;ptrsize:4;");
        return rdb_response_send_packet(res);
    }
    if (cmd_match_str(cmd, "qProcessInfo")) {
        /* The debugger is asking us to describe the "process" getting debugged. */
        /* We make up a process with id 1. */
        rdb_response_write_str(res, "pid:1;triple:");
        rdb_response_write_str_hex(res, "v810-unknown-vb");
        rdb_response_write_str(res, "endian:little;ptrsize:4;");
        return rdb_response_send_packet(res);
    }
    if (cmd_match_str(cmd, "qRegisterInfo")) {
        uint32_t reg_no;

        /* The debugger is asking for information about a specific register. */
        if (!cmd_match_hex_number(cmd, &reg_no)) return 1;
        if (reg_no <= PC_INDEX) {
            rdb_response_write_str(res, REGISTERS[reg_no]);
        }
        return rdb_response_send_packet(res);
    }
    if (cmd_match_str(cmd, "qfThreadInfo")) {
        /* The debugger is asking us to list all threads. Return a list with "thread 1". */
        rdb_response_write_str(res, "mp1.t1");
        return rdb_response_send_packet(res);
    }
    if (cmd_match_str(cmd, "qsThreadInfo")) {
        /* The debugger is asking us to list all threads. */
        rdb_response_write_str(res, "l");
        return rdb_response_send_packet(res);
    }
    if (cmd_match_str(cmd, "vCont?")) {
        /* The debugger is asking which vCont commands we support. */
        rdb_response_write_str(res, "c;C;s;S");
        return rdb_response_send_packet(res);
    }
    if (cmd_match_str(cmd, "qC")) {
        /* The debugger is asking for the current thread id. Return "thread 1". */
        rdb_response_write_str(res, "QCp1.t1");
        return rdb_response_send_packet(res);
    }
    if (cmd_match_str(cmd, "p")) {
        uint32_t reg_no, reg_value;

        /* read a register. */
        if (!cmd_match_hex_number(cmd, &reg_no)) return 1;
        if (reg_no > PC_INDEX) {
            return rdb_response_send_packet(res);
        }

        if (reg_no == PC_INDEX) {
            reg_value = vbGetProgramCounter(sim);
        } else if (reg_no > 31) {
            reg_value = vbGetSystemRegister(sim, SYSTEM_REGISTERS[reg_no - 32]);
        } else {
            reg_value = vbGetProgramRegister(sim, reg_no);
        }
        rdb_response_write_i32_hex(res, reg_value);
        return rdb_response_send_packet(res);
    }
    if (cmd_match_str(cmd, "P")) {
        uint32_t reg_no, reg_value;
        uint8_t reg_bytes[4];

        /* write a register. */
        if (!cmd_match_hex_number(cmd, &reg_no)) return -1;
        if (!cmd_match_str(cmd, "=")) return -1;
        if (!cmd_match_hex_bytes(cmd, 4, reg_bytes)) return -1;

        reg_value = ((uint32_t) (reg_bytes[3]) << 24) |
                            ((uint32_t) (reg_bytes[2]) << 16) |
                            ((uint32_t) (reg_bytes[1]) << 8) |
                            ((uint32_t) reg_bytes[0]);

        if (reg_no > PC_INDEX) {
            return rdb_response_send_packet(res);
        }
        if (reg_no == PC_INDEX) {
            vbSetProgramCounter(sim, reg_value);
        } else if (reg_no > 31) {
            vbSetSystemRegister(sim, SYSTEM_REGISTERS[reg_no - 32], reg_value);
        } else {
            vbSetProgramRegister(sim, reg_no, reg_value);
        }
        rdb_response_write_str(res, "OK");
        return rdb_response_send_packet(res);
    }
    if (cmd_match_str(cmd, "Hc-1")) {
        /* Set the "current thread" for future commands to all threads (thread -1). */
        rdb_response_write_str(res, "OK");
        return rdb_response_send_packet(res);
    }
    if (cmd_match_str(cmd, "c")) {
        /* The debugger has told us to run until we are stopped. */
        /* Don't send a response to this until we receive an ETX (when the debugger pauses us). */
        *running = true;
        return 0;
    }
    if (cmd_match_str(cmd, "\x03")) {
        /* Received an ETX, indicating that the server wants to cancel the "c" command from before. */
        *running = false;
        /* Send the response to the "c" command from before. */
        rdb_response_write_str(res, "T05thread:p1.t1;threads:p1.t1");
        return rdb_response_send_packet(res);
    }
    if (cmd_match_str(cmd, "?")) {
        /* The debugger has asked us why we stopped */
        rdb_response_write_str(res, "T");
        rdb_response_write_str(res, *running ? "00" : "05");
        rdb_response_write_str(res, "thread:p1.t1;threads:p1.t1;");
        return rdb_response_send_packet(res);
    }
    if (cmd_match_str(cmd, "m")) {
        /* read memory */
        uint32_t i, address, len;
        if (!cmd_match_hex_number(cmd, &address)) return -1;
        if (!cmd_match_str(cmd, ",")) return -1;
        if (!cmd_match_hex_number(cmd, &len)) return -1;

        for (i = 0; i < len; ++i) {
            uint8_t byte = vbRead(sim, address + i, VB_U8);
            rdb_response_write_i8_hex(res, byte);
        }
        return rdb_response_send_packet(res);
    }
    fprintf(stderr, "Unrecognized command.\n");
    return rdb_response_send_packet(res);
}