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gdbstub: Protocol fixes and improvements, IDA now works properly

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This commit is contained in:
richardg867
2022-06-19 01:08:34 -03:00
committed by GitHub
parent 75676a3f2a
commit 51f8cb3634
1 changed files with 97 additions and 22 deletions
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119
src/gdbstub.c
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@@ -43,7 +43,7 @@
#define FAST_RESPONSE(s) \
strcpy(client->response, s); \
client->response_pos = sizeof(s);
client->response_pos = sizeof(s) - 1;
#define FAST_RESPONSE_HEX(s) gdbstub_client_respond_hex(client, (uint8_t *) s, sizeof(s));
enum {
@@ -118,7 +118,7 @@ typedef struct _gdbstub_client_ {
event_t *processed_event, *response_event;
uint16_t last_io_base, last_io_len;
uint16_t last_io_base, last_io_len, last_io_value;
struct _gdbstub_client_ *next;
} gdbstub_client_t;
@@ -155,20 +155,23 @@ gdbstub_log(const char *fmt, ...)
static x86seg *segment_regs[] = { &cpu_state.seg_cs, &cpu_state.seg_ss, &cpu_state.seg_ds, &cpu_state.seg_es, &cpu_state.seg_fs, &cpu_state.seg_gs };
static uint32_t *cr_regs[] = { &cpu_state.CR0.l, &cr2, &cr3, &cr4 };
static void *fpu_regs[] = { &cpu_state.npxc, &cpu_state.npxs, NULL, &x87_pc_seg, &x87_pc_off, &x87_op_seg, &x87_op_off };
static const char target_xml[] = /* based on qemu's i386-32bit.xml */
static const char target_xml[] = /* QEMU gdb-xml/i386-32bit.xml with modifications (described in comments) */
// clang-format off
"<?xml version=\"1.0\"?>"
"<!DOCTYPE target SYSTEM \"gdb-target.dtd\">"
"<target>"
"<architecture>i8086</architecture>"
"<architecture>i8086</architecture>" /* start in 16-bit mode to work around known GDB bug preventing 32->16 switching */
""
"<feature name=\"org.gnu.gdb.i386.core\">"
"<flags id=\"i386_eflags\" size=\"4\">"
"<field name=\"\" start=\"22\" end=\"31\"/>"
"<field name=\"ID\" start=\"21\" end=\"21\"/>"
"<field name=\"VIP\" start=\"20\" end=\"20\"/>"
"<field name=\"VIF\" start=\"19\" end=\"19\"/>"
"<field name=\"AC\" start=\"18\" end=\"18\"/>"
"<field name=\"VM\" start=\"17\" end=\"17\"/>"
"<field name=\"RF\" start=\"16\" end=\"16\"/>"
"<field name=\"\" start=\"15\" end=\"15\"/>"
"<field name=\"NT\" start=\"14\" end=\"14\"/>"
"<field name=\"IOPL\" start=\"12\" end=\"13\"/>"
"<field name=\"OF\" start=\"11\" end=\"11\"/>"
@@ -177,12 +180,14 @@ static const char target_xml[] = /* based on qemu's i386-32bit.xml */
"<field name=\"TF\" start=\"8\" end=\"8\"/>"
"<field name=\"SF\" start=\"7\" end=\"7\"/>"
"<field name=\"ZF\" start=\"6\" end=\"6\"/>"
"<field name=\"\" start=\"5\" end=\"5\"/>"
"<field name=\"AF\" start=\"4\" end=\"4\"/>"
"<field name=\"PF\" start=\"2\" end=\"2\"/>"
"<field name=\"\" start=\"1\" end=\"1\"/>"
"<field name=\"CF\" start=\"0\" end=\"0\"/>"
"</flags>"
""
"<reg name=\"eax\" bitsize=\"32\" type=\"int32\"/>"
"<reg name=\"eax\" bitsize=\"32\" type=\"int32\" regnum=\"0\"/>"
"<reg name=\"ecx\" bitsize=\"32\" type=\"int32\"/>"
"<reg name=\"edx\" bitsize=\"32\" type=\"int32\"/>"
"<reg name=\"ebx\" bitsize=\"32\" type=\"int32\"/>"
@@ -190,6 +195,7 @@ static const char target_xml[] = /* based on qemu's i386-32bit.xml */
"<reg name=\"ebp\" bitsize=\"32\" type=\"data_ptr\"/>"
"<reg name=\"esi\" bitsize=\"32\" type=\"int32\"/>"
"<reg name=\"edi\" bitsize=\"32\" type=\"int32\"/>"
""
"<reg name=\"eip\" bitsize=\"32\" type=\"code_ptr\"/>"
"<reg name=\"eflags\" bitsize=\"32\" type=\"i386_eflags\"/>"
""
@@ -200,9 +206,6 @@ static const char target_xml[] = /* based on qemu's i386-32bit.xml */
"<reg name=\"fs\" bitsize=\"16\" type=\"int32\"/>"
"<reg name=\"gs\" bitsize=\"16\" type=\"int32\"/>"
""
"<reg name=\"fs_base\" bitsize=\"32\" type=\"int32\"/>"
"<reg name=\"gs_base\" bitsize=\"32\" type=\"int32\"/>"
""
"<flags id=\"i386_cr0\" size=\"4\">"
"<field name=\"PG\" start=\"31\" end=\"31\"/>"
"<field name=\"CD\" start=\"30\" end=\"30\"/>"
@@ -363,7 +366,7 @@ gdbstub_hex_encode(int c)
if (c < 10)
return c + '0';
else
return c - 10 + 'A';
return c - 10 + 'a';
}
static int
@@ -564,13 +567,21 @@ gdbstub_client_write_reg(int index, uint8_t *buf)
case GDB_REG_MM0 ... GDB_REG_MM7:
width = 8;
cpu_state.MM[index - GDB_REG_MM0].q = *((uint64_t *) &buf);
cpu_state.MM[index - GDB_REG_MM0].q = *((uint64_t *) buf);
break;
default:
width = 0;
}
#ifdef ENABLE_GDBSTUB_LOG
char logbuf[256], *p = logbuf + sprintf(logbuf, "GDB Stub: Setting register %d to ", index);
for (int i = width - 1; i >= 0; i--)
p += sprintf(p, "%02X", buf[i]);
sprintf(p, "\n");
gdbstub_log(logbuf);
#endif
return width;
}
@@ -681,8 +692,8 @@ gdbstub_client_read_reg(int index, uint8_t *buf)
break;
case GDB_REG_MM0 ... GDB_REG_MM7:
width = 8;
cpu_state.MM[index - GDB_REG_MM0].q = *((uint64_t *) &buf);
width = 8;
*((uint64_t *) buf) = cpu_state.MM[index - GDB_REG_MM0].q;
break;
default:
@@ -735,7 +746,7 @@ gdbstub_client_packet(gdbstub_client_t *client)
send(client->socket, "+", 1, 0);
/* Block other responses from being written while this one (if any is produced) isn't acknowledged. */
if ((client->packet[0] != 'c') && (client->packet[0] != 's')) {
if ((client->packet[0] != 'c') && (client->packet[0] != 's') && (client->packet[0] != 'v')) {
thread_wait_event(client->response_event, -1);
thread_reset_event(client->response_event);
}
@@ -783,11 +794,15 @@ ok:
case 'G': /* write all registers */
/* Write the values of all registers. */
for (i = 0; i < GDB_REG_MAX; i++) {
if (i == GDB_REG_MAX)
goto e22;
if (!gdbstub_client_read_hex(client, buf, sizeof(buf)))
break;
client->packet_pos += gdbstub_client_write_reg(i, buf);
client->packet_pos += gdbstub_client_write_reg(i, buf) << 1;
}
break;
/* Respond positively. */
goto ok;
case 'H': /* set thread */
/* Read operation type and thread ID. */
@@ -1016,6 +1031,10 @@ e00:
break;
}
}
} else if (!strncmp(client->response, "Attached", 8)) {
FAST_RESPONSE("1");
} else if (!strcmp(client->response, "C")) {
FAST_RESPONSE("QC1");
} else if (!strcmp(client->response, "Rcmd")) {
/* Read and decode command in-place. */
i = gdbstub_client_read_hex(client, (uint8_t *) client->packet, strlen(client->packet) - client->packet_pos);
@@ -1027,19 +1046,24 @@ e00:
p = strtok_r(client->packet, " ", &strtok_save);
if (!p)
goto ok;
i = strlen(p) - 1; /* get last character offset */
/* Interpret the command. */
if (p[0] == 'i') {
/* Read I/O operation width. */
l = (p[1] == 'n') ? p[2] : p[1];
l = (i < 1) ? '\0' : p[i];
/* Read optional I/O port. */
if (!(p = strtok_r(NULL, " ", &strtok_save)) || !gdbstub_num_decode(p, &j, GDB_MODE_HEX) || (j < 0) || (j >= 65536))
j = client->last_io_base;
else
client->last_io_base = j;
/* Read optional length. */
if (!(p = strtok_r(NULL, " ", &strtok_save)) || !gdbstub_num_decode(p, &k, GDB_MODE_BASE10))
k = client->last_io_len;
else
client->last_io_len = k;
/* Clamp length. */
if (k < 1)
@@ -1091,6 +1115,57 @@ e00:
client->response_pos = 0;
gdbstub_client_respond_hex(client, (uint8_t *) &client->packet, client->packet_pos);
break;
} else if (p[0] == 'o') {
/* Read I/O operation width. */
l = (i < 1) ? '\0' : p[i];
/* Read optional I/O port. */
if (!(p = strtok_r(NULL, " ", &strtok_save)) || !gdbstub_num_decode(p, &j, GDB_MODE_HEX) || (j < 0) || (j >= 65536))
j = -1;
/* Read optional value. */
if (!(p = strtok_r(NULL, " ", &strtok_save)) || !gdbstub_num_decode(p, &k, GDB_MODE_HEX)) {
if (j == -1)
k = client->last_io_value;
else
k = j; /* only one specified = treat as value on last port */
j = -1;
}
if (j == -1)
j = client->last_io_base;
else
client->last_io_base = j;
client->last_io_value = k;
/* Write port. */
switch (l) {
case 'd':
case 'l':
outl(j, k);
break;
case 'w':
outw(j, k);
break;
case 'b':
case 't':
case '\0':
outb(j, k);
break;
default:
goto unknown;
}
} else if (p[0] == 'r') {
pc_reset_hard();
} else if ((p[0] == '?') || !strcmp(p, "help")) {
FAST_RESPONSE_HEX(
"Commands:\n"
"- ib/iw/il [port [length]] - Read {length} (default 1) I/O ports starting from {port} (default last)\n"
"- ob/ow/ol [[port] value] - Write {value} to I/O {port} (both default last)\n"
"- r - Hard reset the emulated machine\n");
break;
} else {
unknown:
FAST_RESPONSE_HEX("Unknown command\n");
@@ -1103,7 +1178,6 @@ unknown:
case 'z': /* remove break/watchpoint */
case 'Z': /* insert break/watchpoint */
{
gdbstub_breakpoint_t *breakpoint, *prev_breakpoint = NULL, **first_breakpoint;
/* Parse breakpoint type. */
@@ -1225,7 +1299,6 @@ unknown:
/* Respond positively. */
goto ok;
}
}
end:
/* Send response. */
@@ -1268,7 +1341,7 @@ gdbstub_cpu_exec(int cycs)
/* Populate stop reason if we have stopped. */
stop_reason_len = 0;
if (gdbstub_step > GDBSTUB_EXEC) {
/* Assemble stop reason manually (avoiding sprintf and friends) for performance. */
/* Assemble stop reason manually, avoiding sprintf and friends for performance. */
stop_reason[stop_reason_len++] = 'T';
stop_reason[stop_reason_len++] = '0';
stop_reason[stop_reason_len++] = '0' + ((gdbstub_step == GDBSTUB_BREAK) ? GDB_SIGINT : GDB_SIGTRAP);
@@ -1659,11 +1732,13 @@ gdbstub_init()
.sin_port = htons(port)
};
if (bind(gdbstub_socket, (struct sockaddr *) &bind_addr, sizeof(bind_addr)) == -1) {
pclog("GDB Stub: Failed to bind on port %d (%d)\n", port,
#ifdef _WIN32
pclog("GDB Stub: Failed to bind on port %d (%d)\n", port, WSAGetLastError());
#else
pclog("GDB Stup: Failed to bind on port %d (%d)\n", port, errno);
WSAGetLastError()
#else
errno
#endif
);
gdbstub_socket = -1;
return;
}