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/*
* Copyright (c) 2011 Peter Zotov <whitequark@whitequark.org>
* Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
*/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <stdint.h>
#if defined(_WIN32)
#include <win32_socket.h>
#else
#include <unistd.h>
#include <sys/poll.h>
#endif
#include "gdb-remote.h"
static const char hex[] = "0123456789abcdef";
int gdb_send_packet(int fd, char* data) {
unsigned int data_length = (unsigned int)strlen(data);
int length = data_length + 4;
char* packet = malloc(length); // '$' data (hex) '#' cksum (hex)
memset(packet, 0, length);
packet[0] = '$';
uint8_t cksum = 0;
for (unsigned int i = 0; i < data_length; i++) {
packet[i + 1] = data[i];
cksum += data[i];
}
packet[length - 3] = '#';
packet[length - 2] = hex[cksum >> 4];
packet[length - 1] = hex[cksum & 0xf];
while (1) {
if (write(fd, packet, length) != length) {
free(packet);
return(-2);
}
char ack;
if (read(fd, &ack, 1) != 1) {
free(packet);
return(-2);
}
if (ack == '+') {
free(packet);
return(0);
}
}
}
#define ALLOC_STEP 1024
int gdb_recv_packet(int fd, char** buffer) {
unsigned packet_size = ALLOC_STEP + 1, packet_idx = 0;
uint8_t cksum = 0;
char recv_cksum[3] = {0};
char* packet_buffer = malloc(packet_size);
unsigned state;
if (packet_buffer == NULL) {
return(-2);
}
start:
state = 0;
packet_idx = 0;
/*
* 0: waiting $
* 1: data, waiting #
* 2: cksum 1
* 3: cksum 2
* 4: fin
*/
char c;
while (state != 4) {
if (read(fd, &c, 1) != 1) {
free(packet_buffer);
return(-2);
}
switch (state) {
case 0:
if (c != '$') { /* ignore */
} else {
state = 1;
}
break;
case 1:
if (c == '#') {
state = 2;
} else {
packet_buffer[packet_idx++] = c;
cksum += c;
if (packet_idx == packet_size) {
packet_size += ALLOC_STEP;
void* p = realloc(packet_buffer, packet_size);
if (p != NULL) {
packet_buffer = p;
} else {
free(packet_buffer);
return(-2);
}
}
}
break;
case 2:
recv_cksum[0] = c;
state = 3;
break;
case 3:
recv_cksum[1] = c;
state = 4;
break;
}
}
uint8_t recv_cksum_int = strtoul(recv_cksum, NULL, 16);
if (recv_cksum_int != cksum) {
char nack = '-';
if (write(fd, &nack, 1) != 1) {
free(packet_buffer);
return(-2);
}
goto start;
} else {
char ack = '+';
if (write(fd, &ack, 1) != 1) {
free(packet_buffer);
return(-2);
}
}
packet_buffer[packet_idx] = 0;
*buffer = packet_buffer;
return(packet_idx);
}
/*
* Here we skip any characters which are not \x03, GDB interrupt.
* As we use the mode with ACK, in a (very unlikely) situation of a packet lost
* because of this skipping, it will be resent anyway.
*/
int gdb_check_for_interrupt(int fd) {
struct pollfd pfd;
pfd.fd = fd;
pfd.events = POLLIN;
if (poll(&pfd, 1, 0) != 0) {
char c;
if (read(fd, &c, 1) != 1) {
return(-2);
}
if (c == '\x03') {
return(1); // ^C
}
}
return(0);
}
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