Archipelago » qemu

/*

 * gdb server stub

 * 

 * Copyright (c) 2003 Fabrice Bellard

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or (at your option) any later version.

 *

 * This library is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with this library; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#include <unistd.h>

#include <errno.h>

#include <sys/socket.h>

#include <netinet/in.h>

#include <netinet/tcp.h>

#include <signal.h>

#include "config.h"

#ifdef TARGET_I386

#include "cpu-i386.h"

#endif

#ifdef TARGET_ARM

#include "cpu-arm.h"

#endif

#include "thunk.h"

#include "exec.h"

#define DEBUG_GDB

int gdbstub_fd = -1;

/* return 0 if OK */

static int gdbstub_open(int port)

{

    struct sockaddr_in sockaddr;

    socklen_t len;

    int fd, val, ret;

    fd = socket(PF_INET, SOCK_STREAM, 0);

    if (fd < 0) {

        perror("socket");

        return -1;

    }

    /* allow fast reuse */

    val = 1;

    setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));

    sockaddr.sin_family = AF_INET;

    sockaddr.sin_port = htons(port);

    sockaddr.sin_addr.s_addr = 0;

    ret = bind(fd, (struct sockaddr *)&sockaddr, sizeof(sockaddr));

    if (ret < 0) {

        perror("bind");

        return -1;

    }

    ret = listen(fd, 0);

    if (ret < 0) {

        perror("listen");

        return -1;

    }

    /* now wait for one connection */

    for(;;) {

        len = sizeof(sockaddr);

        gdbstub_fd = accept(fd, (struct sockaddr *)&sockaddr, &len);

        if (gdbstub_fd < 0 && errno != EINTR) {

            perror("accept");

            return -1;

        } else if (gdbstub_fd >= 0) {

            break;

        }

    }

    /* set short latency */

    val = 1;

    setsockopt(gdbstub_fd, SOL_TCP, TCP_NODELAY, &val, sizeof(val));

    return 0;

}

static int get_char(void)

{

    uint8_t ch;

    int ret;

    for(;;) {

        ret = read(gdbstub_fd, &ch, 1);

        if (ret < 0) {

            if (errno != EINTR && errno != EAGAIN)

                return -1;

        } else if (ret == 0) {

            return -1;

        } else {

            break;

        }

    }

    return ch;

}

static void put_buffer(const uint8_t *buf, int len)

{

    int ret;

    while (len > 0) {

        ret = write(gdbstub_fd, buf, len);

        if (ret < 0) {

            if (errno != EINTR && errno != EAGAIN)

                return;

        } else {

            buf += ret;

            len -= ret;

        }

    }

}

static inline int fromhex(int v)

{

    if (v >= '0' && v <= '9')

        return v - '0';

    else if (v >= 'A' && v <= 'F')

        return v - 'A' + 10;

    else if (v >= 'a' && v <= 'f')

        return v - 'a' + 10;

    else

        return 0;

}

static inline int tohex(int v)

{

    if (v < 10)

        return v + '0';

    else

        return v - 10 + 'a';

}

static void memtohex(char *buf, const uint8_t *mem, int len)

{

    int i, c;

    char *q;

    q = buf;

    for(i = 0; i < len; i++) {

        c = mem[i];

        *q++ = tohex(c >> 4);

        *q++ = tohex(c & 0xf);

    }

    *q = '\0';

}

static void hextomem(uint8_t *mem, const char *buf, int len)

{

    int i;

    for(i = 0; i < len; i++) {

        mem[i] = (fromhex(buf[0]) << 4) | fromhex(buf[1]);

        buf += 2;

    }

}

/* return -1 if error or EOF */

static int get_packet(char *buf, int buf_size)

{

    int ch, len, csum, csum1;

    char reply[1];

    for(;;) {

        for(;;) {

            ch = get_char();

            if (ch < 0)

                return -1;

            if (ch == '$')

                break;

        }

        len = 0;

        csum = 0;

        for(;;) {

            ch = get_char();

            if (ch < 0)

                return -1;

            if (ch == '#')

                break;

            if (len > buf_size - 1)

                return -1;

            buf[len++] = ch;

            csum += ch;

        }

        buf[len] = '\0';

        ch = get_char();

        if (ch < 0)

            return -1;

        csum1 = fromhex(ch) << 4;

        ch = get_char();

        if (ch < 0)

            return -1;

        csum1 |= fromhex(ch);

        if ((csum & 0xff) != csum1) {

            reply[0] = '-';

            put_buffer(reply, 1);

        } else {

            reply[0] = '+';

            put_buffer(reply, 1);

            break;

        }

    }

#ifdef DEBUG_GDB

    printf("command='%s'\n", buf);

#endif

    return len;

}

/* return -1 if error, 0 if OK */

static int put_packet(char *buf)

{

    char buf1[3];

    int len, csum, ch, i;

#ifdef DEBUG_GDB

    printf("reply='%s'\n", buf);

#endif

    for(;;) {

        buf1[0] = '$';

        put_buffer(buf1, 1);

        len = strlen(buf);

        put_buffer(buf, len);

        csum = 0;

        for(i = 0; i < len; i++) {

            csum += buf[i];

        }

        buf1[0] = '#';

        buf1[1] = tohex((csum >> 4) & 0xf);

        buf1[2] = tohex((csum) & 0xf);

        put_buffer(buf1, 3);

        ch = get_char();

        if (ch < 0)

            return -1;

        if (ch == '+')

            break;

    }

    return 0;

}

static int memory_rw(uint8_t *buf, uint32_t addr, int len, int is_write)

{

    int l, flags;

    uint32_t page;

    while (len > 0) {

        page = addr & TARGET_PAGE_MASK;

        l = (page + TARGET_PAGE_SIZE) - addr;

        if (l > len)

            l = len;

        flags = page_get_flags(page);

        if (!(flags & PAGE_VALID))

            return -1;

        if (is_write) {

            if (!(flags & PAGE_WRITE))

                return -1;

            memcpy((uint8_t *)addr, buf, l);

        } else {

            if (!(flags & PAGE_READ))

                return -1;

            memcpy(buf, (uint8_t *)addr, l);

        }

        len -= l;

        buf += l;

        addr += l;

    }

    return 0;

}

/* port = 0 means default port */

int cpu_gdbstub(void *opaque, int (*main_loop)(void *opaque), int port)

{

    CPUState *env;

    const char *p;

    int ret, ch, nb_regs, i, type;

    char buf[4096];

    uint8_t mem_buf[2000];

    uint32_t *registers;

    uint32_t addr, len;

    printf("Waiting gdb connection on port %d\n", port);

    if (gdbstub_open(port) < 0)

        return -1;

    printf("Connected\n");

    for(;;) {

        ret = get_packet(buf, sizeof(buf));

        if (ret < 0)

            break;

        p = buf;

        ch = *p++;

        switch(ch) {

        case '?':

            snprintf(buf, sizeof(buf), "S%02x", SIGTRAP);

            put_packet(buf);

            break;

        case 'c':

            if (*p != '\0') {

                addr = strtoul(p, (char **)&p, 16);

                env = cpu_gdbstub_get_env(opaque);

#if defined(TARGET_I386)

                env->eip = addr;

#endif

            }

            ret = main_loop(opaque);

            if (ret == EXCP_DEBUG)

                ret = SIGTRAP;

            else

                ret = 0;

            snprintf(buf, sizeof(buf), "S%02x", ret);

            put_packet(buf);

            break;

        case 'g':

            env = cpu_gdbstub_get_env(opaque);

            registers = (void *)mem_buf;

#if defined(TARGET_I386)

            for(i = 0; i < 8; i++) {

                registers[i] = tswapl(env->regs[i]);

            }

            registers[8] = env->eip;

            registers[9] = env->eflags;

            registers[10] = env->segs[R_CS].selector;

            registers[11] = env->segs[R_SS].selector;

            registers[12] = env->segs[R_DS].selector;

            registers[13] = env->segs[R_ES].selector;

            registers[14] = env->segs[R_FS].selector;

            registers[15] = env->segs[R_GS].selector;

            nb_regs = 16;

#endif

            memtohex(buf, (const uint8_t *)registers, 

                     sizeof(registers[0]) * nb_regs);

            put_packet(buf);

            break;

        case 'G':

            env = cpu_gdbstub_get_env(opaque);

            registers = (void *)mem_buf;

#if defined(TARGET_I386)

            hextomem((uint8_t *)registers, p, 16 * 4);

            for(i = 0; i < 8; i++) {

                env->regs[i] = tswapl(registers[i]);

            }

            env->eip = registers[8];

            env->eflags = registers[9];

#define LOAD_SEG(index, sreg)\

            if (tswapl(registers[index]) != env->segs[sreg].selector)\

                cpu_x86_load_seg(env, sreg, tswapl(registers[index]));

            LOAD_SEG(10, R_CS);

            LOAD_SEG(11, R_SS);

            LOAD_SEG(12, R_DS);

            LOAD_SEG(13, R_ES);

            LOAD_SEG(14, R_FS);

            LOAD_SEG(15, R_GS);

#endif

            put_packet("OK");

            break;

        case 'm':

            addr = strtoul(p, (char **)&p, 16);

            if (*p == ',')

                p++;

            len = strtoul(p, NULL, 16);

            if (memory_rw(mem_buf, addr, len, 0) != 0)

                memset(mem_buf, 0, len);

            memtohex(buf, mem_buf, len);

            put_packet(buf);

            break;

        case 'M':

            addr = strtoul(p, (char **)&p, 16);

            if (*p == ',')

                p++;

            len = strtoul(p, (char **)&p, 16);

            if (*p == ',')

                p++;

            hextomem(mem_buf, p, len);

            if (memory_rw(mem_buf, addr, len, 1) != 0)

                put_packet("ENN");

            else

                put_packet("OK");

            break;

        case 'Z':

            type = strtoul(p, (char **)&p, 16);

            if (*p == ',')

                p++;

            addr = strtoul(p, (char **)&p, 16);

            if (*p == ',')

                p++;

            len = strtoul(p, (char **)&p, 16);

            if (type == 0 || type == 1) {

                env = cpu_gdbstub_get_env(opaque);

                if (cpu_breakpoint_insert(env, addr) < 0)

                    goto breakpoint_error;

                put_packet("OK");

            } else {

            breakpoint_error:

                put_packet("ENN");

            }

            break;

        case 'z':

            type = strtoul(p, (char **)&p, 16);

            if (*p == ',')

                p++;

            addr = strtoul(p, (char **)&p, 16);

            if (*p == ',')

                p++;

            len = strtoul(p, (char **)&p, 16);

            if (type == 0 || type == 1) {

                env = cpu_gdbstub_get_env(opaque);

                cpu_breakpoint_remove(env, addr);

                put_packet("OK");

            } else {

                goto breakpoint_error;

            }

            break;

        default:

            /* put empty packet */

            buf[0] = '\0';

            put_packet(buf);

            break;

        }

    }

    return 0;

}