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eaafa72cf35c0e4e32a48c2bc57a098a8e166aed
xen/tools/debugger/kdd/kdd.c
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Tim Deegan eaafa72cf3 kdd: stop using [0] arrays to access packet contents 
GCC 10 is unhappy about this, and we already use 64k buffers
in the only places where packets are allocated, so move the
64k size into the packet definition.

Reported-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: Tim Deegan <tim@xen.org>
Acked-by: Wei Liu <wl@xen.org>
Release-acked-by: Paul Durrant <paul@xen.org>
(cherry picked from commit 3471cafbdd)
2020-11-09 17:58:19 +00:00

1047 lines
33 KiB
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/*
* kdd.c -- stub for debugging guest OSes with the windows kernel debugger.
*
* Tim Deegan <Tim.Deegan@citrix.com>
*
* Copyright (c) 2007-2010, Citrix Systems Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <ctype.h>
#include <string.h>
#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <unistd.h>
#include <err.h>
#include <errno.h>
#include <inttypes.h>
#include <netdb.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/select.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include "kdd.h"
/* Windows version details */
typedef struct {
uint32_t build;
int w64;
int mp;
char *name;
uint64_t base; /* KernBase: start looking here */
uint32_t range; /* | and search an area this size */
uint32_t version; /* +-> NtBuildNumber */
uint32_t modules; /* +-> PsLoadedModuleList */
uint32_t prcbs; /* +-> KiProcessorBlock */
} kdd_os;
/* State of the debugger stub */
typedef struct {
union {
uint8_t txb[sizeof (kdd_hdr)]; /* Marshalling area for tx */
kdd_pkt txp; /* Also readable as a packet structure */
};
union {
uint8_t rxb[sizeof (kdd_hdr)]; /* Marshalling area for rx */
kdd_pkt rxp; /* Also readable as a packet structure */
};
unsigned int cur; /* Offset into rx where we'll put the next byte */
uint32_t next_id; /* ID of next packet we will send */
int running; /* Are the guest's processors active? */
int cpuid; /* Current selected CPU */
int fd; /* TCP socket for client comms */
FILE *log; /* For tracing output */
int verbosity; /* How much detail to trace */
kdd_guest *guest; /* Arch-specific state for guest control */
kdd_os os; /* OS-specific magic numbers */
} kdd_state;
/*****************************************************************************
* Utility functions
*/
/* Get the instruction pointer */
static uint64_t kdd_get_ip(kdd_state *s)
{
kdd_regs r;
if (!s->os.w64 && kdd_get_regs(s->guest, s->cpuid, &r, 0) == 0)
return r.r32.eip;
else if (s->os.w64 && kdd_get_regs(s->guest, s->cpuid, &r, 1) == 0)
return r.r64.rip;
else
return -1ULL;
}
/* Turn write(2) into a proper blocking write. */
static size_t blocking_write(int fd, const void *buf, size_t count)
{
size_t left = count;
ssize_t r;
while (left > 0 && ((r = write(fd, buf, left)) >= 0 || errno == EINTR)) {
buf += r;
left -= r;
}
return count - left;
}
/* Dump the contents of a complete serial packet into a log file. */
static void kdd_log_pkt(kdd_state *s, char *name, kdd_pkt *p)
{
uint32_t sum = 0;
unsigned int i, j;
uint8_t ascii[17] = {0};
FILE *f = s->log;
if (s->verbosity < 2)
return;
/* Re-check the checksum */
for (i = 0; i < p->h.len; i++)
sum += p->payload[i];
fprintf(f, "\n"
"%s: %s type 0x%4.4"PRIx16" len 0x%4.4"PRIx16
" id 0x%8.8"PRIx32" sum 0x%"PRIx32" (%s: 0x%"PRIx32")\n",
name,
p->h.dir == KDD_DIR_PKT ? "pkt" :
p->h.dir == KDD_DIR_ACK ? "ack" : "???",
(unsigned) p->h.type, p->h.len, p->h.id, p->h.sum,
sum == p->h.sum ? "OK" : "BAD", sum);
/* Hexdump the payload in "canonical" format*/
for (i = 0; i < p->h.len; i ++) {
if (i % 16 == 0) {
memset(ascii, 0, 17);
fprintf(f, "%8.8x ", i);
} else if (i % 8 == 0)
fprintf(f, " ");
fprintf(f, " %2.2x", p->payload[i]);
ascii[i % 16] = (isprint(((int)p->payload[i])) ? p->payload[i] : 0x2e);
if (i % 16 == 15)
fprintf(f, " |%s|\n", ascii);
}
if (i % 16 != 0) {
for (j = i % 16 ; j < 16; j++) {
fprintf(f, "%s", (j == 8) ? " " : " ");
}
fprintf(f, " |%s|\n%8.8x\n", ascii, i);
}
fprintf(f, "\n");
(void) fflush(f);
}
/*****************************************************************************
* Memory access: virtual addresses and syntactic sugar.
*/
#define PAGE_SHIFT (12)
#define PAGE_SIZE (1ULL << PAGE_SHIFT)
static uint32_t kdd_read_physical(kdd_state *s, uint64_t addr,
uint32_t len, void *buf)
{
return kdd_access_physical(s->guest, addr, len, buf, 0);
}
static uint32_t kdd_write_physical(kdd_state *s, uint64_t addr,
uint32_t len, void *buf)
{
return kdd_access_physical(s->guest, addr, len, buf, 1);
}
/* VA->PA conversion. Returns -1ULL for failure. */
static uint64_t v2p(kdd_state *s, int cpuid, uint64_t va)
{
int pg, pae, pse, lma;
int levels, width, bits, shift, offset, i;
uint64_t efer, entry = 0, mask, pa;
kdd_ctrl ctrl;
if (kdd_get_ctrl(s->guest, cpuid, &ctrl, s->os.w64) != 0
|| kdd_rdmsr(s->guest, cpuid, 0xc0000080, &efer) != 0)
return -1ULL;
if (s->os.w64) {
pg = !!(ctrl.c64.cr0 & 0x80000000);
lma = !!(efer & 0x00000400);
pae = !!(ctrl.c64.cr4 & 0x00000020);
pse = !!(ctrl.c64.cr4 & 0x00000010) || pae || lma;
pa = ctrl.c64.cr3 & ~0x0fULL;
} else {
pg = !!(ctrl.c32.cr0 & 0x80000000);
pae = !!(ctrl.c32.cr4 & 0x00000020);
lma = 0;
pse = !!(ctrl.c32.cr4 & 0x00000010) || pae;
pa = ctrl.c32.cr3 & ~0x0fULL;
}
KDD_DEBUG(s, "w64 = %u, pg = %u, pae = %u, pse = %u, lma = %u\n",
s->os.w64, pg, pae, pse, lma);
/* Paging disabled? */
if (!pg)
return va;
/* 32/PAE64? */
if (lma) {
va &= (1ULL<<48) - 1;
width = 8; levels = 4; bits = 9;
} else {
va &= (1ULL<<32) - 1;
if (pae) {
width = 8; levels = 3; bits = 9;
} else {
width = 4; levels = 2; bits = 10;
}
}
KDD_DEBUG(s, "%i levels, va 0x%16.16"PRIx64"\n", levels, va);
/* Walk the appropriate number of levels */
for (i = levels; i > 0; i--) {
shift = PAGE_SHIFT + bits * (i-1);
mask = ((1ULL << bits) - 1) << shift;
offset = ((va & mask) >> shift) * width;
KDD_DEBUG(s, "level %i: mask 0x%16.16"PRIx64" pa 0x%16.16"PRIx64
" offset %i\n",i, mask, pa, offset);
if (kdd_read_physical(s, pa + offset, width, &entry) != width)
return -1ULL; // Bad entry PA
KDD_DEBUG(s, "level %i: entry 0x%16.16"PRIx64"\n", i, entry);
if (!(entry & 0x1))
return -1ULL; // Not present
pa = entry & 0x000ffffffffff000ULL;
if (pse && (i == 2) && (entry & 0x80)) { // Superpage
mask = ((1ULL << (PAGE_SHIFT + bits)) - 1);
return (pa & ~mask) + (va & mask);
}
}
return pa + (va & (PAGE_SIZE - 1));
}
static uint32_t kdd_access_virtual(kdd_state *s, int cpuid, uint64_t addr,
uint32_t len, void *buf, int write)
{
uint64_t pa;
uint32_t chunk, rv, done = 0;
/* Process one page at a time */
while (len > 0) {
chunk = PAGE_SIZE - (addr & (PAGE_SIZE - 1));
if (chunk > len)
chunk = len;
pa = v2p(s, cpuid, addr);
KDD_DEBUG(s, "va 0x%"PRIx64" -> pa 0x%"PRIx64"\n", addr, pa);
if (pa == (uint64_t) -1ULL)
return done;
rv = kdd_access_physical(s->guest, pa, chunk, buf, write);
done += rv;
if (rv != chunk)
return done;
addr += chunk;
buf += chunk;
len -= chunk;
}
return done;
}
static uint32_t kdd_read_virtual(kdd_state *s, int cpuid, uint64_t addr,
uint32_t len, void *buf)
{
return kdd_access_virtual(s, cpuid, addr, len, buf, 0);
}
static uint32_t kdd_write_virtual(kdd_state *s, int cpuid, uint64_t addr,
uint32_t len, void *buf)
{
return kdd_access_virtual(s, cpuid, addr, len, buf, 1);
}
/*****************************************************************************
* Version information and related runes for different Windows flavours
*/
static kdd_os os[] = {
/* Build 64 MP Name &Kernel search base Range +Version +Modules +PRCBs (64b) */
{2195, 0, 0, "w2k sp4 x32 UP", 0xffffffff80400000ULL, 0x00000000, 0x0006d57c, 0x0006e1b8, 0x0},
{2195, 0, 1, "w2k sp4 x32 SMP", 0xffffffff80400000ULL, 0x00000000, 0x0006fa1c, 0x00084520, 0x0},
// PAE/UP, PAE/SMP
{2600, 0, 0, "xp sp2 x32 UP", 0xffffffff804d7000ULL, 0x00000000, 0x00075568, 0x00083b20, 0x0},
{2600, 0, 1, "xp sp2 x32 SMP", 0xffffffff804d7000ULL, 0x00000000, 0x0007d0e8, 0x0008d4a0, 0x0},
// PAE/UP, PAE/SMP
{2600, 0, 0, "xp sp3 x32 UP", 0xffffffff804d7000ULL, 0x00000000, 0x00075be8, 0x000841c0, 0x0},
{2600, 0, 1, "xp sp3 x32 SMP", 0xffffffff804d7000ULL, 0x00000000, 0x0007c0e8, 0x0008c4c0, 0x0},
{2600, 0, 0, "xp sp3 x32p UP", 0xffffffff804d7000ULL, 0x00000000, 0x0006e8e8, 0x0007cfc0, 0x0},
{2600, 0, 1, "xp sp3 x32p SMP", 0xffffffff804d7000ULL, 0x00000000, 0x000760e8, 0x00086720, 0x0},
{3790, 0, 0, "w2k3 sp2 x32 UP", 0xffffffff80800000ULL, 0x00000000, 0x00097128, 0x000a8e48, 0x0},
{3790, 0, 1, "w2k3 sp2 x32 SMP", 0xffffffff80800000ULL, 0x00000000, 0x0009d128, 0x000af9c8, 0x0},
{3790, 0, 0, "w2k3 sp2 x32p UP", 0xffffffff80800000ULL, 0x00000000, 0x0008e128, 0x0009ffa8, 0x0},
{3790, 0, 1, "w2k3 sp2 x32p SMP", 0xffffffff80800000ULL, 0x00000000, 0x00094128, 0x000a6ea8, 0x0},
{3790, 1, 0, "w2k3 sp2 x64 UP", 0xfffff80001000000ULL, 0x00000000, 0x001765d0, 0x0019aae0, 0x0017b100},
{3790, 1, 1, "w2k3 sp2 x64 SMP", 0xfffff80001000000ULL, 0x00000000, 0x001b05e0, 0x001d5100, 0x001b5300},
{6000, 0, 1, "vista sp0 x32p", 0xffffffff81800000ULL, 0x00000000, 0x000a4de4, 0x00111db0, 0x0},
{6001, 0, 1, "vista sp1 x32p", 0xffffffff81000000ULL, 0x0f000000, 0x000af0c4, 0x00117c70, 0x0},
{6001, 1, 1, "w2k8 sp0 x64", 0xfffff80001000000ULL, 0x0f000000, 0x00140bf0, 0x001c5db0, 0x00229640},
{7600, 1, 1, "win7 sp0 x64", 0xfffff80001000000ULL, 0x0f000000, 0x001af770, 0x0023de50, 0x002a8900},
{7601, 0, 1, "win7 sp1 x32p", 0xffffffff81800000ULL, 0x0f000000, 0x000524c4, 0x00149850, 0x0},
{7601, 1, 1, "win7 sp1 x64", 0xfffff80001000000ULL, 0x0f000000, 0x001b2770, 0x00240e90, 0x002ab900},
};
// 1381, 0, 0, "NT4 sp?", 0xffffffff80100000, ?, ?
static kdd_os unknown_os = {0, 0, 0, "unknown OS", 0, 0, 0, 0, 0};
static int check_os(kdd_state *s)
{
kdd_os *v = &s->os;
uint64_t addr, val;
uint32_t width;
int i;
/* Kernel address must be a DOS executable */
val = 0;
if (kdd_read_virtual(s, 0, v->base, 2, &val) != 2 || val != 0x5a4d) {
KDD_DEBUG(s, "not %s: krnl 0x%"PRIx64"\n", v->name, val);
return 0;
}
/* OS version must match. */
val = 0;
if (kdd_read_virtual(s, 0, v->base + v->version, 4, &val) != 4
|| val != (v->build | 0xf0000000) ) {
KDD_DEBUG(s, "not %s: version 0x%"PRIx64"\n", v->name, val);
return 0;
}
/* Module list address must be a circular linked list */
addr = v->base + v->modules;
val = 0;
width = v->w64 ? 8 : 4;
for (i = 0; val != v->base + v->modules && i < 250; i++) {
val = 0;
if (kdd_read_virtual(s, 0, addr, width, &val) != width) {
KDD_DEBUG(s, "not %s: bad module list\n", v->name);
return 0;
}
addr = val;
}
return 1;
}
/* Figure out what OS we're dealing with */
static void find_os(kdd_state *s)
{
int i;
uint64_t limit;
/* We may already have the right one */
if (check_os(s))
return;
/* Try each OS we know about */
for (i = 0; i < (sizeof os / sizeof os[0]); i++) {
s->os = os[i];
/* Try each page in the potential range of kernel load addresses */
for (limit = s->os.base + s->os.range;
s->os.base <= limit;
s->os.base += PAGE_SIZE)
if (check_os(s))
return;
}
s->os = unknown_os;
}
/*****************************************************************************
* How to send packets and acks.
*/
/* Send a serial packet */
static void kdd_tx(kdd_state *s)
{
uint32_t sum = 0;
size_t len;
int i;
/* Fix up the checksum before we send */
for (i = 0; i < s->txp.h.len; i++)
sum += s->txp.payload[i];
s->txp.h.sum = sum;
kdd_log_pkt(s, "TX", &s->txp);
len = s->txp.h.len + sizeof (kdd_hdr);
if (s->txp.h.dir == KDD_DIR_PKT)
/* Append the mysterious 0xaa byte to each packet */
s->txb[len++] = 0xaa;
(void) blocking_write(s->fd, s->txb, len);
}
/* Send an acknowledgement to the client */
static void kdd_send_ack(kdd_state *s, uint32_t id, uint16_t type)
{
s->txp.h.dir = KDD_DIR_ACK;
s->txp.h.type = type;
s->txp.h.len = 0;
s->txp.h.id = id;
s->txp.h.sum = 0;
kdd_tx(s);
}
/* Send a command_packet to the client */
static void kdd_send_cmd(kdd_state *s, uint32_t subtype, size_t extra)
{
s->txp.h.dir = KDD_DIR_PKT;
s->txp.h.type = KDD_PKT_CMD;
s->txp.h.len = sizeof (kdd_cmd) + extra;
s->txp.h.id = (s->next_id ^= 1);
s->txp.h.sum = 0;
s->txp.cmd.subtype = subtype;
kdd_tx(s);
}
/* Cause the client to print a string */
static void kdd_send_string(kdd_state *s, char *fmt, ...)
{
uint32_t len = 0xffff - sizeof (kdd_msg);
char *buf = (char *) s->txb + sizeof (kdd_hdr) + sizeof (kdd_msg);
va_list ap;
va_start(ap, fmt);
len = vsnprintf(buf, len, fmt, ap);
va_end(ap);
s->txp.h.dir = KDD_DIR_PKT;
s->txp.h.type = KDD_PKT_MSG;
s->txp.h.len = sizeof (kdd_msg) + len;
s->txp.h.id = (s->next_id ^= 1);
s->txp.h.sum = 0;
s->txp.msg.subtype = KDD_MSG_PRINT;
s->txp.msg.length = len;
kdd_tx(s);
}
/* Stop the guest and prepare for debugging */
static void kdd_break(kdd_state *s)
{
uint16_t ilen;
KDD_LOG(s, "Break\n");
if (s->running)
kdd_halt(s->guest);
s->running = 0;
{
unsigned int i;
/* XXX debug pattern */
for (i = 0; i < 0x100 ; i++)
s->txb[sizeof (kdd_hdr) + i] = i;
}
/* Send a state-change message to the client so it knows we've stopped */
s->txp.h.dir = KDD_DIR_PKT;
s->txp.h.type = KDD_PKT_STC;
s->txp.h.len = sizeof (kdd_stc);
s->txp.h.id = (s->next_id ^= 1);
s->txp.stc.subtype = KDD_STC_STOP;
s->txp.stc.stop.cpu = s->cpuid;
s->txp.stc.stop.ncpus = kdd_count_cpus(s->guest);
s->txp.stc.stop.kthread = 0; /* Let the debugger figure it out */
s->txp.stc.stop.status = KDD_STC_STATUS_BREAKPOINT;
s->txp.stc.stop.rip1 = s->txp.stc.stop.rip2 = kdd_get_ip(s);
s->txp.stc.stop.nparams = 0;
s->txp.stc.stop.first_chance = 1;
ilen = kdd_read_virtual(s, s->cpuid, s->txp.stc.stop.rip1,
sizeof s->txp.stc.stop.inst, s->txp.stc.stop.inst);
s->txp.stc.stop.ilen = ilen;
/* XXX other fields */
kdd_tx(s);
}
/* Handle an acknowledgement received from the client */
static void kdd_handle_ack(kdd_state *s, uint32_t id, uint16_t type)
{
switch (type) {
case KDD_ACK_OK:
case KDD_ACK_BAD:
break;
case KDD_ACK_RST:
if (id == 0) {
KDD_LOG(s, "Client requests a reset\n");
kdd_send_ack(s, 0xdeadbeef, KDD_ACK_RST);
kdd_send_string(s, "[kdd: connected to %s]\r\n",
kdd_guest_identify(s->guest));
kdd_break(s);
}
break;
default:
KDD_LOG(s, "Unhandled ACK type 0x%4.4x\n", type);
break;
}
}
/*****************************************************************************
* Handlers for each kind of client packet
*/
/* Handle the initial handshake */
static void kdd_handle_handshake(kdd_state *s)
{
/* Figure out what we're looking at */
find_os(s);
kdd_send_string(s, "[kdd: %s @0x%"PRIx64"]\r\n", s->os.name, s->os.base);
/* Respond with some details about the debugger stub we simulate */
s->txp.cmd.shake.u1 = 0x01010101;
s->txp.cmd.shake.status = KDD_STATUS_SUCCESS;
s->txp.cmd.shake.u2 = 0x02020202;
s->txp.cmd.shake.v_major = 0xf;
s->txp.cmd.shake.v_minor = s->os.build;
s->txp.cmd.shake.proto = 6;
s->txp.cmd.shake.flags = (0x02 /* ??? */
| (s->os.mp ? KDD_FLAGS_MP : 0)
| (s->os.w64 ? KDD_FLAGS_64 : 0));
s->txp.cmd.shake.machine = s->os.w64 ? KDD_MACH_x64 : KDD_MACH_x32;
s->txp.cmd.shake.pkts = KDD_PKT_MAX;
s->txp.cmd.shake.states = 0xc; /* ??? */
s->txp.cmd.shake.manips = 0x2e; /* ??? */
s->txp.cmd.shake.u3[0] = 0x33;
s->txp.cmd.shake.u3[1] = 0x44;
s->txp.cmd.shake.u3[2] = 0x55;
s->txp.cmd.shake.kern_addr = s->os.base;
s->txp.cmd.shake.mods_addr = s->os.base + s->os.modules;
s->txp.cmd.shake.data_addr = 0; /* Debugger data probably doesn't exist */
KDD_LOG(s, "Client initial handshake: %s\n", s->os.name);
kdd_send_cmd(s, KDD_CMD_SHAKE, 0);
}
/* Handle set-cpu command */
static void kdd_handle_setcpu(kdd_state *s)
{
KDD_LOG(s, "Switch to CPU %u\n", s->rxp.cmd.setcpu.cpu);
/* This command doesn't get a direct response; instead we send a STOP. */
s->cpuid = s->rxp.cmd.setcpu.cpu;
kdd_break(s);
/* XXX find out whether kd will be happier if we respond to this command after the break. */
}
/* Handle breakpoint commands */
static void kdd_handle_soft_breakpoint(kdd_state *s)
{
KDD_LOG(s, "Soft breakpoint %#"PRIx32" op %#"PRIx32"/%#"PRIx32"\n",
s->rxp.cmd.sbp.bp, s->rxp.cmd.sbp.u1, s->rxp.cmd.sbp.u2);
/* Pretend we did something */
s->txp.cmd.sbp.u1 = s->rxp.cmd.sbp.u1;
s->txp.cmd.sbp.status = KDD_STATUS_SUCCESS;
s->txp.cmd.sbp.u2 = s->rxp.cmd.sbp.u2;
s->txp.cmd.sbp.bp = s->rxp.cmd.sbp.bp;
kdd_send_cmd(s, KDD_CMD_SOFT_BP, 0);
}
static void kdd_handle_hard_breakpoint(kdd_state *s)
{
KDD_LOG(s, "Hard breakpoint @%#"PRIx64"\n", s->rxp.cmd.hbp.address);
kdd_send_string(s, "[kdd: breakpoints aren't implemented yet]\r\n");
s->txp.cmd.hbp.status = KDD_STATUS_FAILURE;
s->txp.cmd.hbp.address = s->rxp.cmd.hbp.address;
kdd_send_cmd(s, KDD_CMD_HARD_BP, 0);
}
/* Register access */
static void kdd_handle_read_regs(kdd_state *s)
{
kdd_regs regs;
uint32_t len = s->os.w64 ? sizeof regs.r64 : sizeof regs.r32;
int cpuid = s->rxp.cmd.regs.cpu;
KDD_LOG(s, "Read CPU %i register state\n", cpuid);
if (kdd_get_regs(s->guest, cpuid, &regs, s->os.w64) == 0) {
memcpy(s->txb + sizeof (kdd_hdr) + sizeof (kdd_cmd), &regs, len);
s->txp.cmd.regs.status = KDD_STATUS_SUCCESS;
} else {
len = 0;
s->txp.cmd.regs.status = KDD_STATUS_FAILURE;
}
s->txp.cmd.regs.cpu = cpuid;
kdd_send_cmd(s, KDD_CMD_READ_REGS, len);
}
static void kdd_handle_write_regs(kdd_state *s)
{
kdd_regs regs;
uint32_t len = s->rxp.h.len - sizeof (kdd_cmd);
uint32_t regsz = s->os.w64 ? sizeof regs.r64 : sizeof regs.r32;
int cpuid = s->rxp.cmd.regs.cpu;
KDD_LOG(s, "Write CPU %i register state\n", cpuid);
s->txp.cmd.regs.status = KDD_STATUS_FAILURE;
if (len >= regsz) {
memcpy(&regs, s->rxb + sizeof (kdd_hdr) + sizeof (kdd_cmd), regsz);
if (kdd_set_regs(s->guest, cpuid, &regs, s->os.w64) == 0)
s->txp.cmd.regs.status = KDD_STATUS_SUCCESS;
}
s->txp.cmd.regs.cpu = cpuid;
kdd_send_cmd(s, KDD_CMD_WRITE_REGS, 0);
}
/* Report control state to the guest */
static void kdd_handle_read_ctrl(kdd_state *s)
{
int i;
kdd_ctrl ctrl;
uint8_t *buf = s->txb + sizeof (kdd_hdr) + sizeof (kdd_cmd);
uint32_t len = s->rxp.cmd.mem.length_req;
uint64_t val, addr = s->rxp.cmd.mem.addr;
KDD_LOG(s, "Read control state: %"PRIu32" bytes @ 0x%"PRIx64"\n",
len, addr);
if (len > (65536 - sizeof(kdd_cmd)))
len = 65536 - sizeof(kdd_cmd);
/* Default contents: a debug-friendly pattern */
for (i = 0; i < len; i++)
((uint8_t*)buf)[i] = (uint8_t) (addr + i);
if (kdd_get_ctrl(s->guest, s->cpuid, &ctrl, s->os.w64)) {
len = 0;
} else if (s->os.w64) {
/* Annoyingly, 64-bit kd relies on the kernel to point it at
* datastructures it could easily find itself with VA reads. */
switch (addr) {
case 0x0: /* KPCR */
case 0x1: /* KPRCB */
case 0x3: /* KTHREAD */
/* First find the PCRB's address */
len = kdd_read_virtual(s, s->cpuid,
s->os.base + s->os.prcbs + 8 * s->cpuid,
8, &val);
if (len != 8)
break;
/* The PCR lives 0x180 bytes before the PRCB */
if (addr == 0)
val -= 0x180;
/* The current thread's address is at offset 0x8 into the PRCB. */
else if (addr == 3)
len = kdd_read_virtual(s, s->cpuid, val + 8, 8, &val);
*(uint64_t *)buf = val;
break;
case 0x2: /* Control registers */
if (len > sizeof ctrl.c64)
len = sizeof ctrl.c64;
memcpy(buf, (uint8_t *)&ctrl, len);
break;
default:
KDD_LOG(s, "Unknown control space 0x%"PRIx64"\n", addr);
len = 0;
}
} else {
/* 32-bit control-register space starts at 0x[2]cc, for 84 bytes */
uint32_t offset = addr - 0xcc;
if (offset > sizeof ctrl.c32)
offset -= 0x2cc;
if (offset > sizeof ctrl.c32 || len > sizeof ctrl.c32 - offset) {
KDD_LOG(s, "Request outside of known control space\n");
len = 0;
} else {
memcpy(buf, ((uint8_t *)&ctrl.c32) + offset, len);
}
}
s->txp.cmd.mem.addr = addr;
s->txp.cmd.mem.length_req = s->rxp.cmd.mem.length_req;
s->txp.cmd.mem.length_rsp = len;
s->txp.cmd.mem.status = ((len) ? KDD_STATUS_SUCCESS : KDD_STATUS_FAILURE);
kdd_send_cmd(s, KDD_CMD_READ_CTRL, len);
}
/* MSR access */
static void kdd_handle_read_msr(kdd_state *s)
{
uint32_t msr = s->rxp.cmd.msr.msr;
uint64_t val;
int ok;
KDD_LOG(s, "Read MSR 0x%"PRIx32"\n", msr);
ok = (kdd_rdmsr(s->guest, s->cpuid, msr, &val) == 0);
s->txp.cmd.msr.msr = msr;
s->txp.cmd.msr.val = val;
s->txp.cmd.msr.status = (ok ? KDD_STATUS_SUCCESS : KDD_STATUS_FAILURE);
kdd_send_cmd(s, KDD_CMD_READ_MSR, 0);
}
static void kdd_handle_write_msr(kdd_state *s)
{
uint32_t msr = s->rxp.cmd.msr.msr;
uint64_t val = s->rxp.cmd.msr.val;
int ok;
KDD_LOG(s, "Write MSR 0x%"PRIx32" = 0x%"PRIx64"\n", msr, val);
ok = (kdd_wrmsr(s->guest, s->cpuid, msr, val) == 0);
s->txp.cmd.msr.msr = msr;
s->txp.cmd.msr.status = (ok ? KDD_STATUS_SUCCESS : KDD_STATUS_FAILURE);
kdd_send_cmd(s, KDD_CMD_WRITE_MSR, 0);
}
/* Read and write guest memory */
static void kdd_handle_memory_access(kdd_state *s)
{
uint32_t len = s->rxp.cmd.mem.length_req;
uint64_t addr = s->rxp.cmd.mem.addr;
uint8_t *buf;
KDD_LOG(s, "Memory access \"%c%c\" (%s): %"PRIu32" bytes"
" @ 0x%"PRIx64"\n",
s->rxp.cmd.subtype & 0xff, (s->rxp.cmd.subtype >>8) & 0xff,
s->rxp.cmd.subtype == KDD_CMD_READ_VA ? "read virt" :
s->rxp.cmd.subtype == KDD_CMD_WRITE_VA ? "write virt" :
s->rxp.cmd.subtype == KDD_CMD_READ_PA ? "read phys" :
s->rxp.cmd.subtype == KDD_CMD_WRITE_PA ? "write phys" : "unknown",
len, addr);
if (len > (65536 - sizeof(kdd_cmd)))
len = 65536 - sizeof(kdd_cmd);
switch(s->rxp.cmd.subtype) {
case KDD_CMD_READ_VA:
buf = s->txb + sizeof (kdd_hdr) + sizeof (kdd_cmd);
len = kdd_read_virtual(s, s->cpuid, addr, len, buf);
break;
case KDD_CMD_WRITE_VA:
buf = s->rxb + sizeof (kdd_hdr) + sizeof (kdd_cmd);
len = kdd_write_virtual(s, s->cpuid, addr, len, buf);
break;
case KDD_CMD_READ_PA:
buf = s->txb + sizeof (kdd_hdr) + sizeof (kdd_cmd);
len = kdd_read_physical(s, addr, len, buf);
break;
case KDD_CMD_WRITE_PA:
buf = s->rxb + sizeof (kdd_hdr) + sizeof (kdd_cmd);
len = kdd_write_physical(s, addr, len, buf);
break;
}
KDD_DEBUG(s, "access returned %"PRIu32"\n", len);
s->txp.cmd.mem.addr = addr;
s->txp.cmd.mem.length_req = s->rxp.cmd.mem.length_req;
s->txp.cmd.mem.length_rsp = len;
s->txp.cmd.mem.status = (len) ? KDD_STATUS_SUCCESS : KDD_STATUS_FAILURE;
kdd_send_cmd(s, s->rxp.cmd.subtype, len);
}
/* Handle a packet received from the client */
static void kdd_handle_pkt(kdd_state *s, kdd_pkt *p)
{
uint32_t sum = 0;
int i;
/* Simple checksum: add all the bytes */
for (i = 0; i < p->h.len; i++)
sum += p->payload[i];
if (p->h.sum != sum) {
kdd_send_ack(s, p->h.id, KDD_ACK_BAD);
return;
}
/* We only understand one kind of packet from the client */
if (p->h.type != KDD_PKT_CMD) {
KDD_LOG(s, "Unhandled PKT type 0x%4.4x\n", p->h.type);
kdd_send_ack(s, p->h.id, KDD_ACK_BAD);
return;
}
/* Ack the packet */
kdd_send_ack(s, p->h.id, KDD_ACK_OK);
/* Clear the TX buffer just for sanity */
memset(s->txb, 0, sizeof(s->txb));
switch (p->cmd.subtype) {
case KDD_CMD_CONT1:
case KDD_CMD_CONT2:
KDD_LOG(s, "Continue: 0x%8.8"PRIx32"\n", p->cmd.cont.reason1);
if (!s->running)
kdd_run(s->guest);
s->running = 1;
/* No reply, just carry on running */
break;
case KDD_CMD_SHAKE:
kdd_handle_handshake(s);
break;
case KDD_CMD_SOFT_BP:
kdd_handle_soft_breakpoint(s);
break;
case KDD_CMD_HARD_BP:
kdd_handle_hard_breakpoint(s);
break;
case KDD_CMD_READ_REGS:
kdd_handle_read_regs(s);
break;
case KDD_CMD_WRITE_REGS:
kdd_handle_write_regs(s);
break;
case KDD_CMD_READ_CTRL:
kdd_handle_read_ctrl(s);
break;
case KDD_CMD_READ_MSR:
kdd_handle_read_msr(s);
break;
case KDD_CMD_WRITE_MSR:
kdd_handle_write_msr(s);
break;
case KDD_CMD_READ_VA:
case KDD_CMD_WRITE_VA:
case KDD_CMD_READ_PA:
case KDD_CMD_WRITE_PA:
kdd_handle_memory_access(s);
break;
case KDD_CMD_WRITE_Z:
/* No response */
break;
case KDD_CMD_SETCPU:
kdd_handle_setcpu(s);
break;
case KDD_CMD_WRITE_CTRL:
default:
KDD_LOG(s, "Unhandled CMD subtype 0x%8.8x\n", p->cmd.subtype);
/* Send back a mirror of the request saying we failed to do
* whatever it was. */
memcpy(s->txb, p, sizeof (kdd_hdr) + sizeof (kdd_cmd));
s->txp.h.len = sizeof (kdd_cmd);
s->txp.cmd.mem.status = KDD_STATUS_FAILURE;
s->txp.h.id = (s->next_id ^= 1);
kdd_tx(s);
break;
}
}
/*****************************************************************************
* Scaffolding to get packets from the client.
*/
/* Set up the debugger state ready for use. Returns a file descriptor and
* a state pointer for use in select() loops. */
static int kdd_init(kdd_state **sp, struct addrinfo *addr,
kdd_guest *guest, FILE *log, int verbosity)
{
kdd_state *s = NULL;
int opt, fd = -1;
s = malloc(sizeof *s);
if (s == NULL) {
fprintf(stderr, "Could not allocate state for kdd: %s\n",
strerror(errno));
goto fail;
}
memset(s, 0, sizeof *s);
s->log = log;
s->verbosity = verbosity;
fd = socket(PF_INET, SOCK_STREAM, 0);
if (fd < 0) {
KDD_LOG(s, "Could not open a socket for kdd: %s\n",
strerror(errno));
goto fail;
}
/* Try to connect to the tcp/serial gateway. */
again:
if (connect(fd, addr->ai_addr, sizeof *addr) != 0) {
if (errno == EINTR)
goto again;
if (addr->ai_next) {
addr = addr->ai_next;
goto again;
}
KDD_LOG(s, "Could not connect TCP stream for kdd: %s\n",
strerror(errno));
goto fail;
}
opt = 1;
setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &opt, sizeof(opt));
s->next_id = 0x80800001;
s->fd = fd;
s->running = 1;
s->cpuid = 0;
s->guest = guest;
s->os = unknown_os;
*sp = s;
KDD_LOG(s, "KDD starts\n");
kdd_break(s);
return fd;
fail:
if (fd >= 0)
close(fd);
free(s);
return -1;
}
/* Callback when the fd is readable, to parse packet data from the byte
* stream. When a complete packet is seen, handle it. The packet can
* then be read in the marshalling buffer, but only until the next call
* to kdd_parse_byte(). */
void kdd_select_callback(kdd_state *s)
{
kdd_pkt *p = &s->rxp;
unsigned int pkt_len = (unsigned) -1;
ssize_t rc, to_read;
/* For easy parsing, read single bytes until we can check the packet
* length, then read in one go to the end. */
if (s->cur < 8
|| (p->h.dir != KDD_DIR_PKT && p->h.dir != KDD_DIR_ACK))
to_read = 1;
else {
/* Extract payload length from the header */
pkt_len = p->h.len + sizeof (kdd_hdr);
/* For some reason, packets always have a trailing 0xAA byte */
if (p->h.dir == KDD_DIR_PKT)
pkt_len++;
to_read = pkt_len - s->cur;
}
rc = read(s->fd, s->rxb + s->cur, to_read);
KDD_DEBUG(s, "read(%i) returns %i\n", (int) to_read, (int) rc);
if (rc <= 0)
/* XXX ignoring failures for now */
return;
/* Break command comes as a single byte */
if (s->cur == 0 && s->rxb[0] == 'b') {
kdd_break(s);
return;
}
/* Remember the bytes we just read */
s->cur += rc;
/* Sync to packet start, which will be "0000" or "iiii" */
if (s->cur < 4)
return;
if (p->h.dir != KDD_DIR_PKT && p->h.dir != KDD_DIR_ACK) {
KDD_LOG(s, "Bad hdr 0x%8.8x: resyncing\n", p->h.dir);
memmove(s->rxb, s->rxb + 1, --s->cur);
return;
}
/* Process complete packets/acks */
if (s->cur >= pkt_len) {
kdd_log_pkt(s, "RX", p);
if (p->h.dir == KDD_DIR_PKT)
kdd_handle_pkt(s, p);
else
kdd_handle_ack(s, p->h.id, p->h.type);
s->cur = 0;
}
}
static void __attribute__((noreturn)) usage(void)
{
fprintf(stderr,
" usage: kdd [-v] <domid> <address> <port>\n"
" \n"
" Makes a TCP connection to <address>:<port> and speaks the kd serial\n"
" protocol over it, to debug Xen domain <domid>.\n"
" To connect a debugger, set up a Windows VM with it serial port confgured\n"
" as \"serial='tcp:<address>:<port>,server,nodelay,nowait'\". Run\n"
" windbg or kd in that VM, connecting to COM1; then run kdd.\n\n");
exit(1);
}
int main(int argc, char **argv)
{
int fd;
int verbosity = 0;
kdd_state *s;
kdd_guest *g;
struct addrinfo *addr;
fd_set fds;
while (argc > 4)
if (!strcmp(argv[1], "-v")) {
verbosity++;
argc--;
argv++;
}
if (argc != 4
|| !(g = kdd_guest_init(argv[1], stdout, verbosity))
|| getaddrinfo(argv[2], argv[3], NULL, &addr) != 0
|| (fd = kdd_init(&s, addr, g, stdout, verbosity)) < 0)
usage();
while (1) {
FD_ZERO(&fds);
FD_SET(fd, &fds);
if (select(fd + 1, &fds, NULL, NULL, NULL) > 0)
kdd_select_callback(s);
}
return 0;
}
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