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libc/libgloss/debug.c

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/*
* Copyright (c) 1995, 1996 Cygnus Support
*
* The authors hereby grant permission to use, copy, modify, distribute,
* and license this software and its documentation for any purpose, provided
* that existing copyright notices are retained in all copies and that this
* notice is included verbatim in any distributions. No written agreement,
* license, or royalty fee is required for any of the authorized uses.
* Modifications to this software may be copyrighted by their authors
* and need not follow the licensing terms described here, provided that
* the new terms are clearly indicated on the first page of each file where
* they apply.
*/
/*
* A debug packet whose contents are <data> looks like:
*
* $ <data> # CSUM1 CSUM2
*
* <data> must be ASCII alphanumeric and cannot include characters
* '$' or '#'. If <data> starts with two characters followed by
* ':', then the existing stubs interpret this as a sequence number.
*
* CSUM1 and CSUM2 are ascii hex representation of an 8-bit
* checksum of <data>, the most significant nibble is sent first.
* the hex digits 0-9,a-f are used.
*
* We respond with:
*
* + - if CSUM is correct and ready for next packet
* - - if CSUM is incorrect
*
* <data> is as follows:
* Most values are encoded in ascii hex digits.
*/
#include "debug.h"
#include <signal.h>
/*
* buffers that hold the packets while they're being constructed.
*/
char packet_in_buf[BUFMAX];
char packet_out_buf[BUFMAX];
int packet_index;
/*
* indicate to caller of mem2hex or hex2mem that there has been an error.
* 0 means ok, 1 means error
*/
volatile int mem_err = 0;
/*
* 1 means print debugging messages from the target, 0 means be quiet. This is
* changed by gdb_debug().
*/
int remote_debug = 0;
/*
* indicate whether the debug vectors ahave been initialized
* 0 means not yet, 1 means yep, it's ready.
*/
int initialized = 0;
/*
* These variables are instantialted in the GDB stub code.
*/
/* this is a list of signal to exception mappings. */
extern struct trap_info hard_trap_info[];
/* this is a memory fault exception handler, used by mem2hex & hex2mem */
extern void set_mem_fault_trap();
/*
* print debugging messages. This uses print, rather than one of the
* stdio routines, cause if there are stack or memory problems, the
* stdio routines don't work.
* params are the debug level, and the string to print
* it doesn't return anything.
*/
void
debuglog(int level, char *msg)
{
char *p;
unsigned char buf[BUFMAX];
char newmsg[BUFMAX];
int i;
if (level > remote_debug)
return;
if ((level <0) || (level > 100)) {
print ("ERROR: debug print level out of range");
return;
}
/* convert some characters so it'll look right in the log */
p = newmsg;
for (i = 0 ; msg[i] != '\0'; i++) {
if (i > BUFMAX)
print ("\r\nERROR: Debug message too long\r\n");
switch (msg[i]) {
case '\n': /* newlines */
*p++ = '\\';
*p++ = 'n';
continue;
case '\r': /* carriage returns */
*p++ = '\\';
*p++ = 'r';
continue;
case '\033': /* escape */
*p++ = '\\';
*p++ = 'e';
continue;
case '\t': /* tab */
*p++ = '\\';
*p++ = 't';
continue;
case '\b': /* backspace */
*p++ = '\\';
*p++ = 'b';
continue;
default: /* no change */
*p++ = msg[i];
}
if (msg[i] < 26) { /* modify control characters */
*p++ = '^';
*p++ = msg[i] + 'A';
continue;
}
if (msg[i] >= 127) { /* modify control characters */
*p++ = '!';
*p++ = msg[i] + 'A';
continue;
}
}
*p = '\0'; /* terminate the string */
print (newmsg);
print ("\r\n");
}
/*
* convert an ascii hex digit to a number.
* param is hex digit.
* returns a decimal digit.
*/
int
hex2digit (int digit)
{
if (digit == 0)
return 0;
if (digit >= '0' && digit <= '9')
return digit - '0';
if (digit >= 'a' && digit <= 'f')
return digit - 'a' + 10;
if (digit >= 'A' && digit <= 'F')
return digit - 'A' + 10;
/* shouldn't ever get this far */
return ERROR;
}
/*
* convert number NIB to a hex digit.
* param is a decimal digit.
* returns a hex digit.
*/
char
digit2hex(int digit)
{
if (digit < 10)
return '0' + digit;
else
return 'a' + digit - 10;
}
/*
* Convert the memory pointed to by mem into hex, placing result in buf.
* Return a pointer to the last char put in buf (null), in case of mem fault,
* return 0.
* If MAY_FAULT is non-zero, then we will handle memory faults by returning
* a 0, else treat a fault like any other fault in the stub.
*/
unsigned char *
mem2hex(unsigned char *mem, unsigned char *buf, int count, int may_fault)
{
unsigned char ch;
DEBUG (1, "In mem2hex");
set_mem_fault_trap(MAY_FAULT);
while (count-- > 0) {
ch = *mem++;
if (mem_err) {
DEBUG (1, "memory fault in mem2hex");
return 0;
}
*buf++ = digit2hex(ch >> 4);
*buf++ = digit2hex(ch & 0xf);
}
*buf = 0;
set_mem_fault_trap(OK);
return buf;
}
/*
* Convert the hex array pointed to by buf into binary to be placed in mem
* return a pointer to the character AFTER the last byte written
*/
unsigned char *
hex2mem(unsigned char *buf, unsigned char *mem, int count, int may_fault)
{
int i;
unsigned char ch;
DEBUG (1, "In hex2mem");
set_mem_fault_trap(may_fault);
for (i=0; i<count; i++) {
ch = hex2digit(*buf++) << 4;
ch |= hex2digit(*buf++);
*mem++ = ch;
if (mem_err)
return 0;
}
set_mem_fault_trap(0);
return mem;
}
/*
* while we find nice hex chars, build an int.
* param is a pointer to the string.
* returns the int in the param field, and the number of chars processed.
*/
int
hex2int (char **ptr, int *intValue)
{
int numChars = 0;
int hexValue;
*intValue = 0;
while (**ptr)
{
hexValue = hex2digit(**ptr);
if (hexValue < 0)
break;
*intValue = (*intValue << 4) | hexValue;
numChars ++;
(*ptr)++;
}
return (numChars);
}
/*
* Scan for the sequence $<data>#<checksum>
*/
void
getpacket(unsigned char *buffer)
{
unsigned char checksum;
unsigned char xmitcsum;
int i;
int count;
unsigned char ch;
do {
/* wait around for the start character, ignore all other characters */
while ((ch = (inbyte() & 0x7f)) != '$') ;
checksum = 0;
xmitcsum = -1;
count = 0;
/* now, read until a # or end of buffer is found */
while (count < BUFMAX) {
ch = inbyte() & 0x7f;
if (ch == '#')
break;
checksum = checksum + ch;
buffer[count] = ch;
count = count + 1;
}
if (count >= BUFMAX)
continue;
buffer[count] = 0;
if (ch == '#') {
xmitcsum = hex2digit(inbyte() & 0x7f) << 4;
xmitcsum |= hex2digit(inbyte() & 0x7f);
#if 1
/* Humans shouldn't have to figure out checksums to type to it. */
outbyte ('+');
return;
#endif
if (checksum != xmitcsum)
outbyte('-'); /* failed checksum */
else {
outbyte('+'); /* successful transfer */
/* if a sequence char is present, reply the sequence ID */
if (buffer[2] == ':') {
outbyte(buffer[0]);
outbyte(buffer[1]);
/* remove sequence chars from buffer */
count = strlen(buffer);
for (i=3; i <= count; i++)
buffer[i-3] = buffer[i];
}
}
}
}
while (checksum != xmitcsum);
}
/*
* Send the packet in buffer.
*/
void
putpacket(unsigned char *buffer)
{
unsigned char checksum;
int count;
unsigned char ch;
/* $<packet info>#<checksum>. */
do {
outbyte('$');
checksum = 0;
count = 0;
while (ch = buffer[count]) {
if (! outbyte(ch))
return;
checksum += ch;
count += 1;
}
outbyte('#');
outbyte(digit2hex(checksum >> 4));
outbyte(digit2hex(checksum & 0xf));
}
while ((inbyte() & 0x7f) != '+');
}
/*
*
*/
void
gdb_event_loop(int sigval, unsigned long *registers)
{
int addr;
int length;
unsigned char *ptr;
ptr = packet_out_buf;
DEBUG (1, "In gdb_event_loop");
while (1) {
packet_out_buf[0] = 0;
getpacket(packet_in_buf);
ptr = &packet_in_buf[1];
switch (packet_in_buf[0]) {
case '?': /* get the last known signal */
gdb_last_signal(sigval);
break;
case 'd': /* toggle debug messages from the stub */
gdb_toggle();
break;
case 'g': /* return the value of the CPU registers */
target_read_registers(registers);
break;
case 'G': /* set the value of the CPU registers - return OK */
target_write_registers(registers);
break;
case 'm': /* mAA..AA,LLLL Read LLLL bytes at address AA..AA */
/* Try to read %x,%x. */
if (hex2int((char **)&ptr, &addr)
&& *ptr++ == ','
&& hex2int((char **)&ptr, &length)) {
gdb_read_memory(addr, length);
} else {
make_return_packet(1);
}
break;
case 'M': /* MAA..AA,LLLL: Write LLLL bytes at address AA.AA return OK */
/* Try to read '%x,%x:'. */
if (hex2int((char **)&ptr, &addr)
&& *ptr++ == ','
&& hex2int((char **)&ptr, &length)
&& *ptr++ == ':') {
gdb_write_memory (addr, length, ptr);
} else {
make_return_packet(2);
}
break;
case 'c': /* cAA..AA Continue at address AA..AA(optional) */
/* try to read optional parameter, pc unchanged if no parm */
if (hex2int((char **)&ptr, &addr)) {
write_pc(registers, addr);
}
/*
* we need to flush the instruction cache here, as we may have
* deposited a breakpoint, and the icache probably has no way of
* knowing that a data ref to some location may have changed
* something that is in the instruction cache.
*/
flush_i_cache();
/* by returning, we pick up execution where we left off */
return;
/* kill the program */
case 'k' :
gdb_kill();
break;
case 'r': /* Reset */
target_reset();
break;
} /* switch */
/* reply to the request */
putpacket(packet_out_buf);
}
DEBUG (1, "Leaving handle_exception()");
}
/* Convert the hardware trap type code to a unix signal number. */
int
computeSignal(int tt)
{
struct trap_info *ht;
for (ht = hard_trap_info; ht->tt && ht->signo; ht++)
if (ht->tt == tt)
return ht->signo;
return SIGHUP; /* default for things we don't know about */
}
/*
* Set up exception handlers for tracing and breakpoints
*/
void
set_debug_traps()
{
struct trap_info *ht;
DEBUG (1, "Entering set_debug_traps()");
if (hard_trap_info->tt == 0) {
print ("ERROR: ARG#$@%^&*!! no hard trap info!!\r\n");
}
for (ht = hard_trap_info; ht->tt && ht->signo; ht++) {
exception_handler(ht->tt, (unsigned long)default_trap_hook);
}
/* In case GDB is started before us, ack any packets (presumably
"$?#xx") sitting there. */
outbyte ('+');
initialized = 1;
DEBUG (1, "Leaving set_debug_traps()");
}
/*
* make a return packet.
* param is the value to return.
* 0 = OK, any other value is converted to a two digit hex number.
* returns a string or "OK" or "ENN", where NN is the error number. Each N
* is an ASCII encoded hex digit.
*/
char *
make_return_packet(int val)
{
if (val == 0) {
packet_out_buf[0] = 'O';
packet_out_buf[1] = 'K';
packet_out_buf[2] = 0;
} else {
packet_out_buf[0] = 'E';
packet_out_buf[1] = digit2hex((val >> 4) & 0xf);
packet_out_buf[2] = digit2hex(val & 0xf);
packet_out_buf[3] = 0;
}
return(packet_out_buf);
}
/*
* g - read registers.
* no params.
* returns a vector of words, size is NUM_REGS.
*/
char *
gdb_read_registers()
{
}
/*
* G - write registers.
* param is a vector of words, size is NUM_REGS.
* returns an OK or an error number.
*/
char *
gdb_write_registers(char *regs)
{
}
/*
* m - read memory.
* params are the address to start the read at and the number of
* bytes to read.
* returns a vector of nbytes or an error number.
* Can be fewer bytes than requested if able to read only part of the
* data.
*/
char *
gdb_read_memory(long addr, int nbytes)
{
if (mem2hex((char *)addr, packet_out_buf, nbytes, MAY_FAULT))
return(packet_out_buf);
else {
return(make_return_packet(3));
}
}
/*
* M write memory
* params are the address to start writing to, the number of
* bytes to write, and the new values of the bytes.
* returns an OK or an error number.
*/
char *
gdb_write_memory(long addr, int nbytes, char *mem)
{
if (hex2mem(mem, (char *)addr, nbytes, MAY_FAULT))
return(make_return_packet(OK));
else {
return(make_return_packet(3));
}
}
/*
* c - continue at address.
* param is the address to start at, and an optional signal. If
* sig is zero, then ignore it.
* returns an OK or an error number.
*/
char *
gdb_continue(int sig, long addr)
{
}
/*
* s - step instruction(s)
* param is the address to start at, and an optional signal. If
* sig is zero, then ignore it.
* returns an OK or an error number.
*/
char *
gdb_step(int sig, long addr)
{
}
/*
* k - kill program.
* no params.
* returns an OK or an error number.
*/
char *
gdb_kill()
{
/* generically, we can't do anything for this command */
return(make_return_packet(OK));
}
/*
* ? - last signal.
* no params.
* returns the last signal number.
*/
char *
gdb_last_signal(int val)
{
DEBUG (1, "Entering gdb_last_signal()");
packet_out_buf[0] = 'S';
packet_out_buf[1] = digit2hex(val >> 4);
packet_out_buf[2] = digit2hex(val & 0xf);
packet_out_buf[3] = 0;
DEBUG (1, "Leaving gdb_last_signal()");
return (packet_out_buf);
}
/*
* b - change baud rate.
* param is the new baudrate
* returns the baud rate.
*/
char *
gdb_baudrate(int baud)
{
/* generically, we can't do anything for this command */
return(make_return_packet(OK));
}
/*
* T - dump state.
* no params.
* returns the signal number, the registers, the thread ID, and
* possible extensions in a vector that looks like:
* TAAn...:r...;n...:r...;n...:r...; where:
* AA = signal number
* n... = register number (hex)
* r... = register contents
* n... = `thread'
* r... = thread process ID. This is a hex integer.
* n... = other string not starting with valid hex digit.
* gdb should ignore this n,r pair and go on to
* the next. This way we can extend the protocol.
*/
char *
gdb_dump_state()
{
}
/*
* D - host requests a detach
* no params.
* returns either a S, T, W, or X command.
* returns an OK or an error number.
*/
char *
gdb_detach()
{
}
/*
* H - set thread.
* params are the command to execute and the thread ID.
* cmd = 'c' for thread used in step and continue;
* cmd = 'g' for thread used in other operations.
* tid = -1 for all threads.
* tid = zero, pick a thread,any thread.
* returns an OK or an error number.
*/
char *
gdb_set_thread(int cmd, int tid)
{
/* generically, we can't do anything for this command */
return(make_return_packet(OK));
}
/*
* p - read one register.
* param is the register number.
* returns the register value or ENN.
*/
char *
gdb_read_reg(int reg)
{
/* generically, we can't do anything for this command */
return(make_return_packet(OK));
}
/*
* P - write one register.
* params are the register number, and it's new value.
* returns the register value or ENN.
*/
char *
gdb_write_reg(int reg, long val)
{
/* generically, we can't do anything for this command */
return(make_return_packet(OK));
}
/*
* W - process exited.
* no params.
* returns the exit status.
*/
char *
gdb_exited()
{
/* generically, we can't do anything for this command */
return(make_return_packet(OK));
}
/*
* X - process terminated.
* no params.
* returns the last signal.
*/
char *
gdb_terminated()
{
}
/*
* O - hex encoding.
* params are a vector of bytes, and the number of bytes to encode.
* returns a vector of ASCII encoded hex numbers.
*/
char *
gdb_hex(char *str, int nbytes)
{
}
/*
* A - tread alive request.
* param is the thread ID.
* returns an OK or an error number.
*/
char *
gdb_thread_alive(int tid)
{
/* generically, we can't do anything for this command */
return(make_return_packet(OK));
}
/*
* ! - extended protocol.
* no params.
* returns an OK or an error number.
*/
char *
gdb_extended()
{
/* generically, we can't do anything for this command */
return(make_return_packet(OK));
}
/*
* d - toggle gdb stub diagnostics.
* no params.
* returns an OK or an error number.
*/
char *
gdb_debug()
{
if (remote_debug > 0)
remote_debug = 0;
else
remote_debug = 1;
return(make_return_packet(OK));
}
/*
* d - toggle gdb stub.
* no params.
* returns an OK or an error number.
*/
char *
gdb_toggle()
{
static int level = 0;
if (remote_debug) {
level = remote_debug;
remote_debug = 0;
} else {
remote_debug = level;
}
return(make_return_packet(OK));
}
/*
* r - reset target
* no params.
* returns an OK or an error number.
*/
char *
gdb_reset()
{
/* generically, we can't do anything for this command */
return(make_return_packet(OK));
}
/*
* t - search backwards.
* params are the address to start searching from, a pattern to match, and
* the mask to use.
* FIXME: not entirely sure what this is supposed to return.
*/
char *
gdb_search(long addr, long pat, long mask)
{
/* generically, we can't do anything for this command */
return(make_return_packet(OK));
}
/*
* q - general get query.
* param is a string, that's the query to be executed.
* FIXME: not entirely sure what this is supposed to return.
*/
char *
gdb_get_query(char *query)
{
/* generically, we can't do anything for this command */
return(make_return_packet(OK));
}
/*
* Q - general set query
* param is a string, that's the query to be executed.
* FIXME: not entirely sure what this means.
* returns an OK or an error number.
*/
char *
gdb_set(char *query)
{
/* generically, we can't do anything for this command */
return(make_return_packet(OK));
}
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