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  • /***************************************************************************
     *   Copyright (C) 2005 by Dominic Rath                                    *
     *   Dominic.Rath@gmx.de                                                   *
     *                                                                         *
    
     *   Copyright (C) 2007,2008 Øyvind Harboe                                 *
    
     *   Copyright (C) 2008 by Spencer Oliver                                  *
     *   spen@spen-soft.co.uk                                                  *
     *                                                                         *
    
     *   This program is free software; you can redistribute it and/or modify  *
     *   it under the terms of the GNU General Public License as published by  *
     *   the Free Software Foundation; either version 2 of the License, or     *
     *   (at your option) any later version.                                   *
     *                                                                         *
     *   This program 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 General Public License for more details.                          *
     *                                                                         *
     *   You should have received a copy of the GNU General Public License     *
     *   along with this program; if not, write to the                         *
     *   Free Software Foundation, Inc.,                                       *
     *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
     ***************************************************************************/
    #ifdef HAVE_CONFIG_H
    #include "config.h"
    #endif
    
    #include "gdb_server.h"
    
    #include "target_request.h"
    #include "register.h"
    
    #include "server.h"
    #include "flash.h"
    
    #include "image.h"
    #include "jtag.h"
    
    
    
    #if 0
    #define _DEBUG_GDB_IO_
    #endif
    
    
    static int gdb_breakpoint_override;
    static enum breakpoint_type gdb_breakpoint_override_type;
    
    
    extern int gdb_error(connection_t *connection, int retval);
    
    static unsigned short gdb_port = 3333;
    
    static const char *DIGITS = "0123456789abcdef";
    
    
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    static void gdb_log_callback(void *priv, const char *file, int line,
    
    		const char *function, const char *string);
    
    
    enum gdb_detach_mode
    {
    	GDB_DETACH_RESUME,
    	GDB_DETACH_RESET,
    	GDB_DETACH_HALT,
    	GDB_DETACH_NOTHING
    };
    
    /* target behaviour on gdb detach */
    enum gdb_detach_mode detach_mode = GDB_DETACH_RESUME;
    
    
    /* number of gdb connections, mainly to supress gdb related debugging spam
     * in helper/log.c when no gdb connections are actually active */
    int gdb_actual_connections;
    
    
    /* set if we are sending a memory map to gdb
     * via qXfer:memory-map:read packet */
    
    /* enabled by default*/
    int gdb_use_memory_map = 1;
    /* enabled by default*/
    int gdb_flash_program = 1;
    
    
    /* if set, data aborts cause an error to be reported in memory read packets
     * see the code in gdb_read_memory_packet() for further explanations */
    int gdb_report_data_abort = 0;
    
    int gdb_last_signal(target_t *target)
    {
    	switch (target->debug_reason)
    	{
    		case DBG_REASON_DBGRQ:
    			return 0x2; /* SIGINT */
    		case DBG_REASON_BREAKPOINT:
    		case DBG_REASON_WATCHPOINT:
    		case DBG_REASON_WPTANDBKPT:
    			return 0x05; /* SIGTRAP */
    		case DBG_REASON_SINGLESTEP:
    			return 0x05; /* SIGTRAP */
    		case DBG_REASON_NOTHALTED:
    			return 0x0; /* no signal... shouldn't happen */
    		default:
    
    			LOG_USER("undefined debug reason %d - target needs reset", target->debug_reason);
    
    			return 0x0;
    	}
    }
    
    int check_pending(connection_t *connection, int timeout_s, int *got_data)
    {
    	/* a non-blocking socket will block if there is 0 bytes available on the socket,
    	 * but return with as many bytes as are available immediately
    	 */
    	struct timeval tv;
    	fd_set read_fds;
    	gdb_connection_t *gdb_con = connection->priv;
    	int t;
    
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    	if (got_data == NULL)
    
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    	*got_data = 0;
    
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    	if (gdb_con->buf_cnt > 0)
    
    	{
    		*got_data = 1;
    		return ERROR_OK;
    	}
    
    	FD_ZERO(&read_fds);
    	FD_SET(connection->fd, &read_fds);
    
    	tv.tv_sec = timeout_s;
    	tv.tv_usec = 0;
    
    	if (socket_select(connection->fd + 1, &read_fds, NULL, NULL, &tv) == 0)
    
    	{
    		/* This can typically be because a "monitor" command took too long
    		 * before printing any progress messages
    		 */
    
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    		if (timeout_s > 0)
    
    		{
    			return ERROR_GDB_TIMEOUT;
    		} else
    		{
    			return ERROR_OK;
    		}
    
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    	*got_data = FD_ISSET(connection->fd, &read_fds) != 0;
    
    	return ERROR_OK;
    
    }
    
    int gdb_get_char(connection_t *connection, int* next_char)
    {
    	gdb_connection_t *gdb_con = connection->priv;
    
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    	int retval = ERROR_OK;
    
    
    #ifdef _DEBUG_GDB_IO_
    	char *debug_buffer;
    #endif
    
    	if (gdb_con->buf_cnt-- > 0)
    	{
    		*next_char = *(gdb_con->buf_p++);
    		if (gdb_con->buf_cnt > 0)
    			connection->input_pending = 1;
    		else
    			connection->input_pending = 0;
    
    #ifdef _DEBUG_GDB_IO_
    
    		LOG_DEBUG("returned char '%c' (0x%2.2x)", *next_char, *next_char);
    
    #endif
    
    		return ERROR_OK;
    	}
    
    	for (;;)
    	{
    
    		if (connection->service->type == CONNECTION_PIPE)
    		{
    			gdb_con->buf_cnt = read(connection->fd, gdb_con->buffer, GDB_BUFFER_SIZE);
    		}
    		else
    		{
    			retval = check_pending(connection, 1, NULL);
    			if (retval != ERROR_OK)
    				return retval;
    			gdb_con->buf_cnt = read_socket(connection->fd, gdb_con->buffer, GDB_BUFFER_SIZE);
    		}
    
    		if (gdb_con->buf_cnt > 0)
    		{
    			break;
    		}
    		if (gdb_con->buf_cnt == 0)
    		{
    			gdb_con->closed = 1;
    			return ERROR_SERVER_REMOTE_CLOSED;
    		}
    
    #ifdef _WIN32
    		errno = WSAGetLastError();
    
    
    		switch (errno)
    
    		{
    			case WSAEWOULDBLOCK:
    				usleep(1000);
    				break;
    			case WSAECONNABORTED:
    
    				gdb_con->closed = 1;
    
    				return ERROR_SERVER_REMOTE_CLOSED;
    			case WSAECONNRESET:
    
    				gdb_con->closed = 1;
    
    				return ERROR_SERVER_REMOTE_CLOSED;
    			default:
    
    				LOG_ERROR("read: %d", errno);
    
    				exit(-1);
    		}
    #else
    
    		switch (errno)
    
    		{
    			case EAGAIN:
    				usleep(1000);
    				break;
    			case ECONNABORTED:
    
    				gdb_con->closed = 1;
    
    				return ERROR_SERVER_REMOTE_CLOSED;
    			case ECONNRESET:
    
    				gdb_con->closed = 1;
    
    				return ERROR_SERVER_REMOTE_CLOSED;
    			default:
    
    				LOG_ERROR("read: %s", strerror(errno));
    
    				gdb_con->closed = 1;
    
    				return ERROR_SERVER_REMOTE_CLOSED;
    		}
    #endif
    	}
    
    #ifdef _DEBUG_GDB_IO_
    	debug_buffer = malloc(gdb_con->buf_cnt + 1);
    	memcpy(debug_buffer, gdb_con->buffer, gdb_con->buf_cnt);
    	debug_buffer[gdb_con->buf_cnt] = 0;
    
    	LOG_DEBUG("received '%s'", debug_buffer);
    
    	free(debug_buffer);
    #endif
    
    	gdb_con->buf_p = gdb_con->buffer;
    	gdb_con->buf_cnt--;
    	*next_char = *(gdb_con->buf_p++);
    	if (gdb_con->buf_cnt > 0)
    		connection->input_pending = 1;
    	else
    
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    		connection->input_pending = 0;
    
    #ifdef _DEBUG_GDB_IO_
    
    	LOG_DEBUG("returned char '%c' (0x%2.2x)", *next_char, *next_char);
    
    }
    
    int gdb_putback_char(connection_t *connection, int last_char)
    {
    	gdb_connection_t *gdb_con = connection->priv;
    
    	if (gdb_con->buf_p > gdb_con->buffer)
    	{
    		*(--gdb_con->buf_p) = last_char;
    		gdb_con->buf_cnt++;
    	}
    	else
    	{
    
    		LOG_ERROR("BUG: couldn't put character back");
    
    	}
    
    	return ERROR_OK;
    }
    
    /* The only way we can detect that the socket is closed is the first time
     * we write to it, we will fail. Subsequent write operations will
     * succeed. Shudder! */
    int gdb_write(connection_t *connection, void *data, int len)
    {
    	gdb_connection_t *gdb_con = connection->priv;
    	if (gdb_con->closed)
    		return ERROR_SERVER_REMOTE_CLOSED;
    
    	if (connection->service->type == CONNECTION_PIPE)
    
    		/* write to stdout */
    		if (write(STDOUT_FILENO, data, len) == len)
    		{
    			return ERROR_OK;
    		}
    	}
    	else
    	{
    		if (write_socket(connection->fd, data, len) == len)
    		{
    			return ERROR_OK;
    		}
    
    	}
    	gdb_con->closed = 1;
    	return ERROR_SERVER_REMOTE_CLOSED;
    }
    
    int gdb_put_packet_inner(connection_t *connection, char *buffer, int len)
    {
    	int i;
    	unsigned char my_checksum = 0;
    #ifdef _DEBUG_GDB_IO_
    	char *debug_buffer;
    #endif
    	int reply;
    	int retval;
    	gdb_connection_t *gdb_con = connection->priv;
    
    	for (i = 0; i < len; i++)
    		my_checksum += buffer[i];
    
    
    #ifdef _DEBUG_GDB_IO_
    
    	 * At this point we should have nothing in the input queue from GDB,
    	 * however sometimes '-' is sent even though we've already received
    	 * an ACK (+) for everything we've sent off.
    	 */
    	int gotdata;
    	for (;;)
    	{
    
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    		if ((retval = check_pending(connection, 0, &gotdata)) != ERROR_OK)
    
    			return retval;
    		if (!gotdata)
    			break;
    		if ((retval = gdb_get_char(connection, &reply)) != ERROR_OK)
    			return retval;
    
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    		if (reply == '$') {
    
    			/* fix a problem with some IAR tools */
    
    			gdb_putback_char(connection, reply);
    
    			LOG_DEBUG("Unexpected start of new packet");
    			break;
    		}
    
    
    		LOG_WARNING("Discard unexpected char %c", reply);
    
    	while (1)
    	{
    #ifdef _DEBUG_GDB_IO_
    		debug_buffer = malloc(len + 1);
    		memcpy(debug_buffer, buffer, len);
    		debug_buffer[len] = 0;
    
    		LOG_DEBUG("sending packet '$%s#%2.2x'", debug_buffer, my_checksum);
    
    		free(debug_buffer);
    #endif
    
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    		char local_buffer[1024];
    		local_buffer[0] = '$';
    
    		if ((size_t)len + 4 <= sizeof(local_buffer))
    
    			/* performance gain on smaller packets by only a single call to gdb_write() */
    
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    			memcpy(local_buffer + 1, buffer, len++);
    
    			local_buffer[len++] = '#';
    			local_buffer[len++] = DIGITS[(my_checksum >> 4) & 0xf];
    			local_buffer[len++] = DIGITS[my_checksum & 0xf];
    
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    			if ((retval = gdb_write(connection, local_buffer, len)) != ERROR_OK)
    
    			/* larger packets are transmitted directly from caller supplied buffer
    			   by several calls to gdb_write() to avoid dynamic allocation */
    			local_buffer[1] = '#';
    			local_buffer[2] = DIGITS[(my_checksum >> 4) & 0xf];
    			local_buffer[3] = DIGITS[my_checksum & 0xf];
    
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    			if ((retval = gdb_write(connection, local_buffer, 1)) != ERROR_OK)
    
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    			if ((retval = gdb_write(connection, buffer, len)) != ERROR_OK)
    
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    			if ((retval = gdb_write(connection, local_buffer + 1, 3)) != ERROR_OK)
    
    		if ((retval = gdb_get_char(connection, &reply)) != ERROR_OK)
    			return retval;
    
    		if (reply == '+')
    			break;
    		else if (reply == '-')
    		{
    			/* Stop sending output packets for now */
    			log_remove_callback(gdb_log_callback, connection);
    
    			LOG_WARNING("negative reply, retrying");
    
    		}
    		else if (reply == 0x3)
    		{
    			gdb_con->ctrl_c = 1;
    			if ((retval = gdb_get_char(connection, &reply)) != ERROR_OK)
    				return retval;
    			if (reply == '+')
    				break;
    			else if (reply == '-')
    			{
    				/* Stop sending output packets for now */
    				log_remove_callback(gdb_log_callback, connection);
    
    				LOG_WARNING("negative reply, retrying");
    
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    			else if (reply == '$') {
    
    				LOG_ERROR("GDB missing ack(1) - assumed good");
    
    				gdb_putback_char(connection, reply);
    
    				return ERROR_OK;
    			} else {
    
    				LOG_ERROR("unknown character(1) 0x%2.2x in reply, dropping connection", reply);
    
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    				gdb_con->closed = 1;
    
    				return ERROR_SERVER_REMOTE_CLOSED;
    			}
    
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    		else if (reply == '$') {
    
    			LOG_ERROR("GDB missing ack(2) - assumed good");
    
    			gdb_putback_char(connection, reply);
    
    			return ERROR_OK;
    
    			LOG_ERROR("unknown character(2) 0x%2.2x in reply, dropping connection", reply);
    
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    			gdb_con->closed = 1;
    
    			return ERROR_SERVER_REMOTE_CLOSED;
    		}
    	}
    	if (gdb_con->closed)
    		return ERROR_SERVER_REMOTE_CLOSED;
    
    	return ERROR_OK;
    }
    
    int gdb_put_packet(connection_t *connection, char *buffer, int len)
    {
    	gdb_connection_t *gdb_con = connection->priv;
    	gdb_con->busy = 1;
    	int retval = gdb_put_packet_inner(connection, buffer, len);
    	gdb_con->busy = 0;
    
    
    	/* we sent some data, reset timer for keep alive messages */
    	kept_alive();
    
    
    	return retval;
    }
    
    
    static __inline__ int fetch_packet(connection_t *connection, int *checksum_ok, int noack, int *len, char *buffer)
    
    	unsigned char my_checksum = 0;
    	char checksum[3];
    
    	int character;
    
    	int retval;
    
    	gdb_connection_t *gdb_con = connection->priv;
    	my_checksum = 0;
    
    	int count = 0;
    
    	count = 0;
    	for (;;)
    	{
    		/* The common case is that we have an entire packet with no escape chars.
    		 * We need to leave at least 2 bytes in the buffer to have
    		 * gdb_get_char() update various bits and bobs correctly.
    		 */
    
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    		if ((gdb_con->buf_cnt > 2) && ((gdb_con->buf_cnt + count) < *len))
    
    		{
    			/* The compiler will struggle a bit with constant propagation and
    			 * aliasing, so we help it by showing that these values do not
    			 * change inside the loop
    			 */
    			int i;
    			char *buf = gdb_con->buf_p;
    			int run = gdb_con->buf_cnt - 2;
    			i = 0;
    			int done = 0;
    			while (i < run)
    			{
    				character = *buf++;
    				i++;
    				if (character == '#')
    				{
    					/* Danger! character can be '#' when esc is
    					 * used so we need an explicit boolean for done here.
    					 */
    					done = 1;
    					break;
    				}
    
    				if (character == '}')
    				{
    					/* data transmitted in binary mode (X packet)
    					 * uses 0x7d as escape character */
    					my_checksum += character & 0xff;
    					character = *buf++;
    					i++;
    					my_checksum += character & 0xff;
    					buffer[count++] = (character ^ 0x20) & 0xff;
    				}
    				else
    				{
    					my_checksum += character & 0xff;
    					buffer[count++] = character & 0xff;
    				}
    			}
    			gdb_con->buf_p += i;
    			gdb_con->buf_cnt -= i;
    			if (done)
    				break;
    		}
    		if (count > *len)
    		{
    			LOG_ERROR("packet buffer too small");
    			return ERROR_GDB_BUFFER_TOO_SMALL;
    		}
    
    		if ((retval = gdb_get_char(connection, &character)) != ERROR_OK)
    			return retval;
    
    		if (character == '#')
    			break;
    
    		if (character == '}')
    		{
    			/* data transmitted in binary mode (X packet)
    			 * uses 0x7d as escape character */
    			my_checksum += character & 0xff;
    			if ((retval = gdb_get_char(connection, &character)) != ERROR_OK)
    				return retval;
    			my_checksum += character & 0xff;
    			buffer[count++] = (character ^ 0x20) & 0xff;
    		}
    		else
    		{
    			my_checksum += character & 0xff;
    			buffer[count++] = character & 0xff;
    		}
    	}
    
    	*len = count;
    
    	if ((retval = gdb_get_char(connection, &character)) != ERROR_OK)
    		return retval;
    	checksum[0] = character;
    	if ((retval = gdb_get_char(connection, &character)) != ERROR_OK)
    		return retval;
    	checksum[1] = character;
    	checksum[2] = 0;
    
    	if (!noack)
    	{
    
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    		*checksum_ok = (my_checksum == strtoul(checksum, NULL, 16));
    
    	return ERROR_OK;
    }
    
    int gdb_get_packet_inner(connection_t *connection, char *buffer, int *len)
    {
    	int character;
    
    	int retval;
    	gdb_connection_t *gdb_con = connection->priv;
    
    	while (1)
    	{
    		do
    		{
    			if ((retval = gdb_get_char(connection, &character)) != ERROR_OK)
    				return retval;
    
    #ifdef _DEBUG_GDB_IO_
    
    			LOG_DEBUG("character: '%c'", character);
    
    #endif
    
    			switch (character)
    			{
    				case '$':
    					break;
    				case '+':
    
    					/* gdb sends a dummy ack '+' at every remote connect - see remote_start_remote (remote.c)
    					 * incase anyone tries to debug why they receive this warning every time */
    
    					LOG_WARNING("acknowledgment received, but no packet pending");
    
    					break;
    				case '-':
    
    					LOG_WARNING("negative acknowledgment, but no packet pending");
    
    					break;
    				case 0x3:
    					gdb_con->ctrl_c = 1;
    					*len = 0;
    					return ERROR_OK;
    				default:
    
    					LOG_WARNING("ignoring character 0x%x", character);
    
    					break;
    			}
    		} while (character != '$');
    
    
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    		/* explicit code expansion here to get faster inlined code in -O3 by not
    		 * calculating checksum
    		 */
    		if (gdb_con->noack_mode)
    		{
    
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    			if ((retval = fetch_packet(connection, &checksum_ok, 1, len, buffer)) != ERROR_OK)
    
    				return retval;
    
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    			if ((retval = fetch_packet(connection, &checksum_ok, 0, len, buffer)) != ERROR_OK)
    
    				return retval;
    
    		if (gdb_con->noack_mode)
    
    			/* checksum is not checked in noack mode */
    			break;
    
    		if (checksum_ok)
    
    			if ((retval = gdb_write(connection, "+", 1)) != ERROR_OK)
    			{
    				return retval;
    			}
    
    	}
    	if (gdb_con->closed)
    		return ERROR_SERVER_REMOTE_CLOSED;
    
    	return ERROR_OK;
    }
    
    int gdb_get_packet(connection_t *connection, char *buffer, int *len)
    {
    	gdb_connection_t *gdb_con = connection->priv;
    	gdb_con->busy = 1;
    	int retval = gdb_get_packet_inner(connection, buffer, len);
    	gdb_con->busy = 0;
    	return retval;
    }
    
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    int gdb_output_con(connection_t *connection, const char* line)
    
    {
    	char *hex_buffer;
    	int i, bin_size;
    
    	bin_size = strlen(line);
    
    
    	hex_buffer = malloc(bin_size*2 + 2);
    
    	if (hex_buffer == NULL)
    		return ERROR_GDB_BUFFER_TOO_SMALL;
    
    
    	hex_buffer[0] = 'O';
    
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    	for (i = 0; i < bin_size; i++)
    
    		snprintf(hex_buffer + 1 + i*2, 3, "%2.2x", line[i]);
    
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    	hex_buffer[bin_size*2 + 1] = 0;
    
    	int retval = gdb_put_packet(connection, hex_buffer, bin_size*2 + 1);
    
    
    	free(hex_buffer);
    
    	return retval;
    
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    int gdb_output(struct command_context_s *context, const char* line)
    
    {
    	/* this will be dumped to the log and also sent as an O packet if possible */
    
    	LOG_USER_N("%s", line);
    
    static void gdb_frontend_halted(struct target_s *target, connection_t *connection)
    {
    	gdb_connection_t *gdb_connection = connection->priv;
    
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    	/* In the GDB protocol when we are stepping or continuing execution,
    
    	 * we have a lingering reply. Upon receiving a halted event
    	 * when we have that lingering packet, we reply to the original
    	 * step or continue packet.
    	 *
    	 * Executing monitor commands can bring the target in and
    	 * out of the running state so we'll see lots of TARGET_EVENT_XXX
    	 * that are to be ignored.
    	 */
    	if (gdb_connection->frontend_state == TARGET_RUNNING)
    	{
    		char sig_reply[4];
    		int signal;
    
    		/* stop forwarding log packets! */
    		log_remove_callback(gdb_log_callback, connection);
    
    		if (gdb_connection->ctrl_c)
    		{
    			signal = 0x2;
    			gdb_connection->ctrl_c = 0;
    		}
    		else
    		{
    			signal = gdb_last_signal(target);
    		}
    
    		snprintf(sig_reply, 4, "T%2.2x", signal);
    		gdb_put_packet(connection, sig_reply, 3);
    		gdb_connection->frontend_state = TARGET_HALTED;
    	}
    }
    
    
    int gdb_target_callback_event_handler(struct target_s *target, enum target_event event, void *priv)
    {
    
    	connection_t *connection = priv;
    
    
    	target_handle_event(target, event);
    
    	switch (event)
    	{
    
    			gdb_frontend_halted(target, connection);
    
    		case TARGET_EVENT_HALTED:
    			target_call_event_callbacks(target, TARGET_EVENT_GDB_END);
    			break;
    
    		case TARGET_EVENT_GDB_FLASH_ERASE_START:
    
    			target_handle_event(target, TARGET_EVENT_OLD_gdb_program_config);
    
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    			if ((retval = jtag_execute_queue()) != ERROR_OK)
    
    			break;
    		default:
    			break;
    	}
    
    	return ERROR_OK;
    }
    
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    int gdb_new_connection(connection_t *connection)
    {
    	gdb_connection_t *gdb_connection = malloc(sizeof(gdb_connection_t));
    	gdb_service_t *gdb_service = connection->service->priv;
    	int retval;
    	int initial_ack;
    
    	connection->priv = gdb_connection;
    
    	/* initialize gdb connection information */
    	gdb_connection->buf_p = gdb_connection->buffer;
    	gdb_connection->buf_cnt = 0;
    	gdb_connection->ctrl_c = 0;
    	gdb_connection->frontend_state = TARGET_HALTED;
    	gdb_connection->vflash_image = NULL;
    	gdb_connection->closed = 0;
    	gdb_connection->busy = 0;
    
    	/* send ACK to GDB for debug request */
    	gdb_write(connection, "+", 1);
    
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    	/* output goes through gdb connection */
    	command_set_output_handler(connection->cmd_ctx, gdb_output, connection);
    
    
    	/* we must remove all breakpoints registered to the target as a previous
    
    	 * GDB session could leave dangling breakpoints if e.g. communication
    
    	 * timed out.
    	 */
    	breakpoint_clear_target(gdb_service->target);
    	watchpoint_clear_target(gdb_service->target);
    
    	/* register callback to be informed about target events */
    
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    	target_register_event_callback(gdb_target_callback_event_handler, connection);
    
    	/* a gdb session just attached, try to put the target in halt mode.
    
    	 * If the halt fails(e.g. target needs a reset, JTAG communication not
    	 * working, etc.), then the GDB connect will succeed as
    	 * the get_gdb_reg_list() will lie and return a register list with
    	 * dummy values.
    
    	 * This allows GDB monitor commands to be run from a GDB init script to
    	 * initialize the target
    
    	 * Also, since the halt() is asynchronous target connect will be
    	 * instantaneous and thus avoiding annoying timeout problems during
    
    	/* FIX!!!! could extended-remote work better here?
    
    	 *  wait a tiny bit for halted state or we just continue. The
    
    	 * GDB register packet will then contain garbage
    
    	 */
    	target_wait_state(gdb_service->target, TARGET_HALTED, 500);
    
    	/* remove the initial ACK from the incoming buffer */
    	if ((retval = gdb_get_char(connection, &initial_ack)) != ERROR_OK)
    		return retval;
    
    
    	/* FIX!!!??? would we actually ever receive a + here???
    
    	if (initial_ack != '+')
    		gdb_putback_char(connection, initial_ack);
    
    	target_call_event_callbacks(gdb_service->target, TARGET_EVENT_GDB_ATTACH);
    
    
    	gdb_actual_connections++;
    
    	LOG_DEBUG("New GDB Connection: %d, Target %s, state: %s",
    		  gdb_actual_connections,
    		  gdb_service->target->cmd_name,
    		  target_state_name(gdb_service->target));
    
    	return ERROR_OK;
    }
    
    
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    int gdb_connection_closed(connection_t *connection)
    
    {
    	gdb_service_t *gdb_service = connection->service->priv;
    	gdb_connection_t *gdb_connection = connection->priv;
    
    
    	/* we're done forwarding messages. Tear down callback before
    	 * cleaning up connection.
    	 */
    	log_remove_callback(gdb_log_callback, connection);
    
    
    	gdb_actual_connections--;
    
    	LOG_DEBUG("GDB Close, Target: %s, state: %s, gdb_actual_connections=%d",
    
    		  gdb_service->target->cmd_name,
    		  target_state_name(gdb_service->target),
    		  gdb_actual_connections);
    
    	/* see if an image built with vFlash commands is left */
    	if (gdb_connection->vflash_image)
    	{
    		image_close(gdb_connection->vflash_image);
    		free(gdb_connection->vflash_image);
    		gdb_connection->vflash_image = NULL;
    	}
    
    	/* if this connection registered a debug-message receiver delete it */
    	delete_debug_msg_receiver(connection->cmd_ctx, gdb_service->target);
    
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    	if (connection->priv)
    	{
    		free(connection->priv);
    		connection->priv = NULL;
    	}
    	else
    	{
    
    		LOG_ERROR("BUG: connection->priv == NULL");
    
    	target_unregister_event_callback(gdb_target_callback_event_handler, connection);
    
    	target_call_event_callbacks(gdb_service->target, TARGET_EVENT_GDB_END);
    
    	target_call_event_callbacks(gdb_service->target, TARGET_EVENT_GDB_DETACH);
    
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    	return ERROR_OK;
    
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    void gdb_send_error(connection_t *connection, uint8_t the_error)
    
    {
    	char err[4];
    
    	snprintf(err, 4, "E%2.2X", the_error);
    
    	gdb_put_packet(connection, err, 3);
    }
    
    int gdb_last_signal_packet(connection_t *connection, target_t *target, char* packet, int packet_size)
    {
    	char sig_reply[4];
    	int signal;
    
    	signal = gdb_last_signal(target);
    
    	snprintf(sig_reply, 4, "S%2.2x", signal);
    	gdb_put_packet(connection, sig_reply, 3);
    
    	return ERROR_OK;
    }
    
    
    static int gdb_reg_pos(target_t *target, int pos, int len)
    {
    	if (target->endianness == TARGET_LITTLE_ENDIAN)
    		return pos;
    	else
    		return len - 1 - pos;
    }
    
    /* Convert register to string of bytes. NB! The # of bits in the
    
     * register might be non-divisible by 8(a byte), in which
    
     * case an entire byte is shown.
     *
     * NB! the format on the wire is the target endianess
     *
     * The format of reg->value is little endian
     *
     */
    
    void gdb_str_to_target(target_t *target, char *tstr, reg_t *reg)
    {
    	int i;
    
    
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    	uint8_t *buf;
    
    	int buf_len;
    	buf = reg->value;
    
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    	buf_len = CEIL(reg->size, 8);
    
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    	for (i = 0; i < buf_len; i++)
    
    		int j = gdb_reg_pos(target, i, buf_len);
    		tstr[i*2]   = DIGITS[(buf[j]>>4) & 0xf];
    
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    		tstr[i*2 + 1] = DIGITS[buf[j]&0xf];
    
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    	}
    
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    	c = toupper(c);
    
    	if (c>='A'&&c<='F')
    	{
    		return c-'A'+10;
    	}
    	LOG_ERROR("BUG: invalid register value %08x", c);
    	return 0;
    }
    
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    void gdb_target_to_reg(target_t *target, char *tstr, int str_len, uint8_t *bin)
    
    	if (str_len % 2)
    	{
    
    		LOG_ERROR("BUG: gdb value with uneven number of characters encountered");
    
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    	for (i = 0; i < str_len; i += 2)
    
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    		uint8_t t = hextoint(tstr[i]) << 4;
    
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    		t |= hextoint(tstr[i + 1]);
    
    
    		int j = gdb_reg_pos(target, i/2, str_len/2);
    		bin[j] = t;
    
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    	}
    
    }
    
    int gdb_get_registers_packet(connection_t *connection, target_t *target, char* packet, int packet_size)
    {
    	reg_t **reg_list;
    	int reg_list_size;
    	int retval;
    	int reg_packet_size = 0;
    	char *reg_packet;
    	char *reg_packet_p;
    	int i;
    
    #ifdef _DEBUG_GDB_IO_
    
    	if ((retval = target_get_gdb_reg_list(target, &reg_list, &reg_list_size)) != ERROR_OK)
    
    		return gdb_error(connection, retval);
    
    	}
    
    	for (i = 0; i < reg_list_size; i++)
    	{
    		reg_packet_size += reg_list[i]->size;
    	}
    
    	reg_packet = malloc(CEIL(reg_packet_size, 8) * 2);
    	reg_packet_p = reg_packet;
    
    	for (i = 0; i < reg_list_size; i++)
    	{
    		gdb_str_to_target(target, reg_packet_p, reg_list[i]);
    		reg_packet_p += CEIL(reg_list[i]->size, 8) * 2;
    	}
    
    #ifdef _DEBUG_GDB_IO_
    	{
    		char *reg_packet_p;
    		reg_packet_p = strndup(reg_packet, CEIL(reg_packet_size, 8) * 2);
    
    		LOG_DEBUG("reg_packet: %s", reg_packet_p);
    
    		free(reg_packet_p);
    	}
    #endif
    
    	gdb_put_packet(connection, reg_packet, CEIL(reg_packet_size, 8) * 2);
    	free(reg_packet);
    
    	free(reg_list);
    
    	return ERROR_OK;
    }
    
    int gdb_set_registers_packet(connection_t *connection, target_t *target, char *packet, int packet_size)