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x50ng/gdbstub.c

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C

/*
* gdb server stub
*
* Copyright (c) 2003-2005 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 <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/poll.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <x49gp.h>
#include "gdbstub.h"
#ifdef _WIN32
/* XXX: these constants may be independent of the host ones even for Unix */
#ifndef SIGTRAP
#define SIGTRAP 5
#endif
#ifndef SIGINT
#define SIGINT 2
#endif
#else
#include <signal.h>
#endif
#define DEBUG_GDB
enum RSState {
RS_IDLE,
RS_GETLINE,
RS_CHKSUM1,
RS_CHKSUM2,
RS_SYSCALL,
};
typedef struct GDBState {
CPUState *env; /* current CPU */
enum RSState state; /* parsing state */
char line_buf[4096];
int line_buf_index;
int line_csum;
char last_packet[4100];
int last_packet_len;
int fd;
int running_state;
} GDBState;
/* XXX: This is not thread safe. Do we care? */
static int gdbserver_fd = -1;
/* XXX: remove this hack. */
static GDBState gdbserver_state;
static int get_char(GDBState *s)
{
uint8_t ch;
int ret;
for(;;) {
ret = recv(s->fd, &ch, 1, 0);
if (ret < 0) {
if (errno != EINTR && errno != EAGAIN)
return -1;
} else if (ret == 0) {
return -1;
} else {
break;
}
}
return ch;
}
/* GDB stub state for use by semihosting syscalls. */
static GDBState *gdb_syscall_state;
static gdb_syscall_complete_cb gdb_current_syscall_cb;
enum {
GDB_SYS_UNKNOWN,
GDB_SYS_ENABLED,
GDB_SYS_DISABLED,
} gdb_syscall_mode;
/* If gdb is connected when the first semihosting syscall occurs then use
remote gdb syscalls. Otherwise use native file IO. */
int use_gdb_syscalls(void)
{
if (gdb_syscall_mode == GDB_SYS_UNKNOWN) {
gdb_syscall_mode = (gdb_syscall_state ? GDB_SYS_ENABLED
: GDB_SYS_DISABLED);
}
return gdb_syscall_mode == GDB_SYS_ENABLED;
}
static void put_buffer(GDBState *s, const uint8_t *buf, int len)
{
int ret;
while (len > 0) {
ret = send(s->fd, buf, len, 0);
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, 0 if OK */
static int put_packet(GDBState *s, char *buf)
{
int len, csum, i;
char *p;
#ifdef DEBUG_GDB
printf("reply='%s'\n", buf);
#endif
for(;;) {
p = s->last_packet;
*(p++) = '$';
len = strlen(buf);
memcpy(p, buf, len);
p += len;
csum = 0;
for(i = 0; i < len; i++) {
csum += buf[i];
}
*(p++) = '#';
*(p++) = tohex((csum >> 4) & 0xf);
*(p++) = tohex((csum) & 0xf);
s->last_packet_len = p - s->last_packet;
put_buffer(s, (uint8_t *) s->last_packet, s->last_packet_len);
i = get_char(s);
if (i < 0)
return -1;
if (i == '+')
break;
}
return 0;
}
static int cpu_gdb_read_registers(CPUState *env, uint8_t *mem_buf)
{
int i;
uint8_t *ptr;
ptr = mem_buf;
/* 16 core integer registers (4 bytes each). */
for (i = 0; i < 16; i++)
{
*(uint32_t *)ptr = tswapl(env->regs[i]);
ptr += 4;
}
/* 8 FPA registers (12 bytes each), FPS (4 bytes).
Not yet implemented. */
memset (ptr, 0, 8 * 12 + 4);
ptr += 8 * 12 + 4;
/* CPSR (4 bytes). */
*(uint32_t *)ptr = tswapl (cpsr_read(env));
ptr += 4;
return ptr - mem_buf;
}
static void cpu_gdb_write_registers(CPUState *env, uint8_t *mem_buf, int size)
{
int i;
uint8_t *ptr;
ptr = mem_buf;
/* Core integer registers. */
for (i = 0; i < 16; i++)
{
env->regs[i] = tswapl(*(uint32_t *)ptr);
ptr += 4;
}
/* Ignore FPA regs and scr. */
ptr += 8 * 12 + 4;
cpsr_write (env, tswapl(*(uint32_t *)ptr), 0xffffffff);
}
static int gdb_handle_packet(GDBState *s, CPUState *env, const char *line_buf)
{
const char *p;
int ch, reg_size, type;
char buf[4096];
uint8_t mem_buf[2000];
uint32_t *registers;
target_ulong addr, len;
#ifdef DEBUG_GDB
printf("command='%s'\n", line_buf);
#endif
p = line_buf;
ch = *p++;
switch(ch) {
case '?':
/* TODO: Make this return the correct value for user-mode. */
snprintf(buf, sizeof(buf), "S%02x", SIGTRAP);
put_packet(s, buf);
break;
case 'c':
if (*p != '\0') {
addr = strtoull(p, (char **)&p, 16);
env->regs[15] = addr;
}
s->running_state = 1;
return RS_IDLE;
case 's':
if (*p != '\0') {
addr = strtoul(p, (char **)&p, 16);
env->regs[15] = addr;
}
cpu_single_step(env, 1);
s->running_state = 1;
return RS_IDLE;
case 'F':
{
target_ulong ret;
target_ulong err;
ret = strtoull(p, (char **)&p, 16);
if (*p == ',') {
p++;
err = strtoull(p, (char **)&p, 16);
} else {
err = 0;
}
if (*p == ',')
p++;
type = *p;
if (gdb_current_syscall_cb)
gdb_current_syscall_cb(s->env, ret, err);
if (type == 'C') {
put_packet(s, "T02");
} else {
s->running_state = 1;
}
}
break;
case 'g':
reg_size = cpu_gdb_read_registers(env, mem_buf);
memtohex(buf, mem_buf, reg_size);
put_packet(s, buf);
break;
case 'G':
registers = (void *)mem_buf;
len = strlen(p) / 2;
hextomem((uint8_t *)registers, p, len);
cpu_gdb_write_registers(env, mem_buf, len);
put_packet(s, "OK");
break;
case 'm':
addr = strtoull(p, (char **)&p, 16);
if (*p == ',')
p++;
len = strtoull(p, NULL, 16);
if (cpu_memory_rw_debug(env, addr, mem_buf, len, 0) != 0) {
put_packet (s, "E14");
} else {
memtohex(buf, mem_buf, len);
put_packet(s, buf);
}
break;
case 'M':
addr = strtoull(p, (char **)&p, 16);
if (*p == ',')
p++;
len = strtoull(p, (char **)&p, 16);
if (*p == ':')
p++;
hextomem(mem_buf, p, len);
if (cpu_memory_rw_debug(env, addr, mem_buf, len, 1) != 0)
put_packet(s, "E14");
else
put_packet(s, "OK");
break;
case 'Z':
type = strtoul(p, (char **)&p, 16);
if (*p == ',')
p++;
addr = strtoull(p, (char **)&p, 16);
if (*p == ',')
p++;
len = strtoull(p, (char **)&p, 16);
if (type == 0 || type == 1) {
if (
#ifdef QEMU_OLD
cpu_breakpoint_insert(env, addr) < 0
#else
cpu_breakpoint_insert(env, addr, BP_GDB, NULL) < 0
#endif
)
goto breakpoint_error;
put_packet(s, "OK");
} else {
breakpoint_error:
put_packet(s, "E22");
}
break;
case 'z':
type = strtoul(p, (char **)&p, 16);
if (*p == ',')
p++;
addr = strtoull(p, (char **)&p, 16);
if (*p == ',')
p++;
len = strtoull(p, (char **)&p, 16);
if (type == 0 || type == 1) {
#ifdef QEMU_OLD
cpu_breakpoint_remove(env, addr);
#else
cpu_breakpoint_remove(env, addr, BP_GDB);
#endif
put_packet(s, "OK");
} else {
goto breakpoint_error;
}
break;
default:
// unknown_command:
/* put empty packet */
buf[0] = '\0';
put_packet(s, buf);
break;
}
return RS_IDLE;
}
extern void tb_flush(CPUState *env);
/* Send a gdb syscall request.
This accepts limited printf-style format specifiers, specifically:
%x - target_ulong argument printed in hex.
%s - string pointer (target_ulong) and length (int) pair. */
void gdb_do_syscall(gdb_syscall_complete_cb cb, char *fmt, ...)
{
va_list va;
char buf[256];
char *p;
target_ulong addr;
GDBState *s;
s = gdb_syscall_state;
if (!s)
return;
gdb_current_syscall_cb = cb;
s->state = RS_IDLE;
va_start(va, fmt);
p = buf;
*(p++) = 'F';
while (*fmt) {
if (*fmt == '%') {
fmt++;
switch (*fmt++) {
case 'x':
addr = va_arg(va, target_ulong);
p += sprintf(p, TARGET_FMT_lx, addr);
break;
case 's':
addr = va_arg(va, target_ulong);
p += sprintf(p, TARGET_FMT_lx "/%x", addr, va_arg(va, int));
break;
default:
fprintf(stderr, "gdbstub: Bad syscall format string '%s'\n",
fmt - 1);
break;
}
} else {
*(p++) = *(fmt++);
}
}
va_end(va);
put_packet(s, buf);
#ifdef QEMU_OLD
cpu_interrupt(s->env, CPU_INTERRUPT_EXIT);
#else
cpu_exit(s->env);
#endif
}
static void gdb_read_byte(GDBState *s, int ch)
{
CPUState *env = s->env;
char buf[256];
int i, csum;
char reply[1];
printf("%s: state %u, byte %02x (%c)\n", __FUNCTION__, s->state, ch, ch);
fflush(stdout);
switch(s->state) {
case RS_IDLE:
if (ch == '$') {
s->line_buf_index = 0;
s->state = RS_GETLINE;
} else if (ch == 0x03) {
snprintf(buf, sizeof(buf), "S%02x", SIGINT);
put_packet(s, buf);
}
break;
case RS_GETLINE:
if (ch == '#') {
s->state = RS_CHKSUM1;
} else if (s->line_buf_index >= sizeof(s->line_buf) - 1) {
s->state = RS_IDLE;
} else {
s->line_buf[s->line_buf_index++] = ch;
}
break;
case RS_CHKSUM1:
s->line_buf[s->line_buf_index] = '\0';
s->line_csum = fromhex(ch) << 4;
s->state = RS_CHKSUM2;
break;
case RS_CHKSUM2:
s->line_csum |= fromhex(ch);
csum = 0;
for(i = 0; i < s->line_buf_index; i++) {
csum += s->line_buf[i];
}
if (s->line_csum != (csum & 0xff)) {
reply[0] = '-';
put_buffer(s, (uint8_t *) reply, 1);
s->state = RS_IDLE;
} else {
reply[0] = '+';
put_buffer(s, (uint8_t *) reply, 1);
s->state = gdb_handle_packet(s, env, s->line_buf);
}
break;
default:
abort();
}
}
int
gdb_handlesig (CPUState *env, int sig)
{
GDBState *s;
char buf[256];
int n;
if (gdbserver_fd < 0)
return sig;
s = &gdbserver_state;
printf("%s: sig: %u\n", __FUNCTION__, sig);
fflush(stdout);
/* disable single step if it was enabled */
cpu_single_step(env, 0);
tb_flush(env);
if (sig != 0)
{
snprintf(buf, sizeof(buf), "S%02x", sig);
put_packet(s, buf);
}
sig = 0;
s->state = RS_IDLE;
s->running_state = 0;
while (s->running_state == 0) {
n = read (s->fd, buf, 256);
if (n > 0)
{
int i;
printf("%s: read: %d\n", __FUNCTION__, n);
fflush(stdout);
for (i = 0; i < n; i++)
gdb_read_byte (s, buf[i]);
}
else if (n == 0 || errno != EAGAIN)
{
/* XXX: Connection closed. Should probably wait for annother
connection before continuing. */
return sig;
}
}
return sig;
}
int
gdb_poll (CPUState *env)
{
GDBState *s;
struct pollfd pfd;
if (gdbserver_fd < 0)
return 0;
s = &gdbserver_state;
pfd.fd = s->fd;
pfd.events = POLLIN | POLLHUP;
if (poll(&pfd, 1, 0) <= 0) {
if (errno != EAGAIN)
return 0;
return 0;
}
printf("%s: revents: %08x\n", __FUNCTION__, pfd.revents);
fflush(stdout);
if (pfd.revents & (POLLIN | POLLHUP))
return 1;
return 0;
}
/* Tell the remote gdb that the process has exited. */
void gdb_exit(CPUState *env, int code)
{
GDBState *s;
char buf[4];
if (gdbserver_fd < 0)
return;
s = &gdbserver_state;
snprintf(buf, sizeof(buf), "W%02x", code);
put_packet(s, buf);
}
static void gdb_accept(void *opaque)
{
GDBState *s;
struct sockaddr_in sockaddr;
socklen_t len;
int val, fd;
for(;;) {
len = sizeof(sockaddr);
fd = accept(gdbserver_fd, (struct sockaddr *)&sockaddr, &len);
if (fd < 0 && errno != EINTR) {
perror("accept");
return;
} else if (fd >= 0) {
break;
}
}
/* set short latency */
val = 1;
setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, (char *)&val, sizeof(val));
s = &gdbserver_state;
memset (s, 0, sizeof (GDBState));
s->env = first_cpu; /* XXX: allow to change CPU */
s->fd = fd;
gdb_syscall_state = s;
fcntl(fd, F_SETFL, O_NONBLOCK);
}
static int gdbserver_open(int port)
{
struct sockaddr_in sockaddr;
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, (char *)&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;
}
return fd;
}
int gdbserver_start(int port)
{
gdbserver_fd = gdbserver_open(port);
if (gdbserver_fd < 0)
return -1;
/* accept connections */
gdb_accept (NULL);
return 0;
}