char* lab_ymodem_receive(int* length, int ymodemg)
{
int stop;
int firstblk;
unsigned char gotch;
int pktsize;
int size = 0;
char* rxbuf = NULL;
int rbytes;
int waitpkts;
stop = 0;
firstblk = 1;
lab_delay(6);
rbytes = 0;
waitpkts = 16;
while (!stop)
{
if (firstblk)
{
if (ymodemg)
lab_putc(GRC);
else
lab_putc(CRC);
}
gotch = getchar();
if (gotch == 0) // timeout
{
waitpkts--;
if (!waitpkts)
{
printk("WARNING: YMODEM receive timed out!\n");
if (rxbuf)
vfree(rxbuf);
return NULL;
}
continue;
}
switch (gotch)
{
case SOH:
pktsize = 128;
goto havesize;
case STX:
pktsize = 1024;
havesize:
{
unsigned char blk;
unsigned char blk255;
unsigned char dbytes[1028];
int i;
blk = getchar();
blk255 = getchar();
for (i=0; i<pktsize+2; i++)
dbytes[i] = getchar();
if (crc16_buf(dbytes, pktsize+2))
{
/* CRC failed, try again */
lab_putc(NAK);
break;
}
if (blk255 != (255-blk))
{
lab_putc(NAK);
break;
}
if (firstblk)
{
int i;
char* buf;
buf = dbytes + strlen(dbytes) + 1;
i = 0;
size = 0;
while (*buf >= '0' && *buf <= '9')
{
size *= 10;
size += *buf - '0';
buf++;
}
*length = size;
size += 1024;
rxbuf = vmalloc(size+1024); // a little more safety...
// printk(">>> YMODEM: getting file of size %d (buf addr: %08X)\n", size-1024, rxbuf);
lab_putc(ACK);
if (ymodemg)
lab_putc(GRC);
else
lab_putc(CRC);
firstblk = 0;
break;
}
if ((rbytes + pktsize) > size)
{
lab_putc(CAN);
lab_putc(CAN);
/* BUFFER OVERRUN!!! */
stop = 1;
break;
}
memcpy(rxbuf+rbytes, dbytes, pktsize);
rbytes += pktsize;
if (!ymodemg)
lab_putc(ACK);
break;
}
case EOT:
lab_putc(ACK);
lab_delay(1);
lab_putc(CRC);
lab_delay(1);
lab_putc(ACK);
lab_delay(1);
lab_putc(CAN);
lab_putc(CAN);
lab_putc(CAN);
lab_putc(CAN);
lab_puts("\x08\x08\x08\x08 \x08\x08\x08\x08");
eatbytes();
stop = 1;
break;
case CAN:
lab_putc(CAN);
lab_putc(CAN);
lab_putc(CAN);
lab_putc(CAN);
lab_puts("\x08\x08\x08\x08 \x08\x08\x08\x08");
stop = 1;
lab_delay(1);
lab_puts("YMODEM transfer aborted\r\n");
if (rxbuf)
vfree(rxbuf);
rxbuf = NULL;
eatbytes();
break;
case 0x03:
case 0xFF:
/* Control-C. We should NAK it if it was line noise,
* but it's more likely to be the user banging on the
* keyboard trying to abort a screwup.
*/
lab_putc(CAN);
lab_putc(CAN);
lab_putc(CAN);
lab_putc(CAN);
lab_puts("\x08\x08\x08\x08 \x08\x08\x08\x08");
eatbytes();
if (rxbuf)
vfree(rxbuf);
rxbuf = NULL;
stop=1;
break;
default:
lab_putc(NAK);
}
}
return rxbuf;
}
/* Returns 0 on success, 1 on corrupt packet, -1 on error (timeout): */
static int receive_packet(char *data, int *length, int use_crc, int timeout){
int i;
unsigned int packet_size, sum;
char c;
*length = 0;
if(receive_byte(&c, timeout) < 0)
return -1;
switch(c){
case SOH:
packet_size = PACKET_SIZE;
break;
case STX:
packet_size = PACKET_1K_SIZE;
break;
case EOT:
return 0;
case CAN:
if(receive_byte(&c, timeout) == 0 && c == CAN){
*length = -1;
return 0;
}
default:
/* This case could be the result of corruption on the first octet
* of the packet, but it's more likely that it's the user banging
* on the terminal trying to abort a transfer. Technically, the
* former case deserves a NAK, but for now we'll just treat this
* as an abort case.
*/
*length = -1;
return 0;
}
*data = c;
for(i = 1; i < (packet_size +
(use_crc ? PACKET_OVERHEAD_CRC : PACKET_OVERHEAD)); ++i)
if(receive_byte(data + i, timeout) < 0)
return -1;
/* Just a sanity check on the sequence number/complement value.
* Caller should check for in-order arrival.
*/
if(data[PACKET_SEQNO_INDEX] !=
(data[PACKET_SEQNO_COMP_INDEX] ^ 0xff) & 0xff)
return 1;
if(use_crc){
/* It seems odd that the CRC doesn't cover the three preamble bytes. */
if(crc16_buf(data + PACKET_HEADER, packet_size + PACKET_TRAILER_CRC) != 0)
return 1;
} else {
for(i = PACKET_HEADER, sum = 0; i < packet_size + PACKET_HEADER; ++i)
sum += data[i];
if((sum & 0xff) != (data[i] & 0xff))
return 1;
}
*length = packet_size;
return 0;
}
