/**
* Read a single character from any console.
*
* @v None -
* @ret character Character read from a console.
* @err None -
*
* A character will be read from the first enabled console device that
* has input available using that console's console_driver::getchar()
* method. If no console has input available to be read, this method
* will block. To perform a non-blocking read, use something like
*
* @code
*
* int key = iskey() ? getchar() : -1;
*
* @endcode
*
* The character read will not be echoed back to any console.
*
*/
int getchar ( void ) {
struct console_driver *console;
int character;
while ( 1 ) {
console = has_input();
if ( console && console->getchar ) {
character = console->getchar ();
break;
}
/* Doze for a while (until the next interrupt). This works
* fine, because the keyboard is interrupt-driven, and the
* timer interrupt (approx. every 50msec) takes care of the
* serial port, which is read by polling. This reduces the
* power dissipation of a modern CPU considerably, and also
* makes Etherboot waiting for user interaction waste a lot
* less CPU time in a VMware session.
*/
cpu_nap();
/* Keep processing background tasks while we wait for
* input.
*/
step();
}
/* CR -> LF translation */
if ( character == '\r' )
character = '\n';
return character;
}
/**
* Receive XenStore response raw data
*
* @v xen Xen hypervisor
* @v data Data buffer, or NULL to discard data
* @v len Length of data
*/
static void xenstore_recv ( struct xen_hypervisor *xen, void *data,
size_t len ) {
struct xenstore_domain_interface *intf = xen->store.intf;
XENSTORE_RING_IDX cons = readl ( &intf->rsp_cons );
XENSTORE_RING_IDX prod;
XENSTORE_RING_IDX idx;
char *bytes = data;
size_t offset = 0;
size_t fill;
DBGCP ( intf, "XENSTORE raw response:\n" );
/* Read one byte at a time */
while ( offset < len ) {
/* Wait for data to be ready */
while ( 1 ) {
prod = readl ( &intf->rsp_prod );
fill = ( prod - cons );
if ( fill > 0 )
break;
DBGC2 ( xen, "." );
cpu_nap();
rmb();
}
/* Read byte */
idx = MASK_XENSTORE_IDX ( cons++ );
if ( data )
bytes[offset++] = readb ( &intf->rsp[idx] );
}
if ( data )
DBGCP_HDA ( intf, MASK_XENSTORE_IDX ( cons - len ), data, len );
/* Update consumer counter */
writel ( cons, &intf->rsp_cons );
wmb();
}
/**
* Send XenStore request raw data
*
* @v xen Xen hypervisor
* @v data Data buffer
* @v len Length of data
*/
static void xenstore_send ( struct xen_hypervisor *xen, const void *data,
size_t len ) {
struct xenstore_domain_interface *intf = xen->store.intf;
XENSTORE_RING_IDX prod = readl ( &intf->req_prod );
XENSTORE_RING_IDX cons;
XENSTORE_RING_IDX idx;
const char *bytes = data;
size_t offset = 0;
size_t fill;
DBGCP ( intf, "XENSTORE raw request:\n" );
DBGCP_HDA ( intf, MASK_XENSTORE_IDX ( prod ), data, len );
/* Write one byte at a time */
while ( offset < len ) {
/* Wait for space to become available */
while ( 1 ) {
cons = readl ( &intf->req_cons );
fill = ( prod - cons );
if ( fill < XENSTORE_RING_SIZE )
break;
DBGC2 ( xen, "." );
cpu_nap();
rmb();
}
/* Write byte */
idx = MASK_XENSTORE_IDX ( prod++ );
writeb ( bytes[offset++], &intf->req[idx] );
}
/* Update producer counter */
wmb();
writel ( prod, &intf->req_prod );
wmb();
}
static size_t gdbudp_recv ( char *buf, size_t len ) {
struct io_buffer *iob;
struct ethhdr *ethhdr;
struct arphdr *arphdr;
struct iphdr *iphdr;
struct udp_header *udphdr;
size_t payload_len;
gdbudp_ensure_netdev_open ( netdev );
for ( ; ; ) {
netdev_poll ( netdev );
while ( ( iob = netdev_rx_dequeue ( netdev ) ) != NULL ) {
/* Ethernet header */
if ( iob_len ( iob ) < sizeof ( *ethhdr ) ) {
goto bad_packet;
}
ethhdr = iob->data;
iob_pull ( iob, sizeof ( *ethhdr ) );
/* Handle ARP requests so the client can find our MAC */
if ( ethhdr->h_protocol == htons ( ETH_P_ARP ) ) {
arphdr = iob->data;
if ( iob_len ( iob ) < sizeof ( *arphdr ) + 2 * ( ETH_ALEN + sizeof ( struct in_addr ) ) ||
arphdr->ar_hrd != htons ( ARPHRD_ETHER ) ||
arphdr->ar_pro != htons ( ETH_P_IP ) ||
arphdr->ar_hln != ETH_ALEN ||
arphdr->ar_pln != sizeof ( struct in_addr ) ||
arphdr->ar_op != htons ( ARPOP_REQUEST ) ||
* ( uint32_t * ) arp_target_pa ( arphdr ) != source_addr.sin_addr.s_addr ) {
goto bad_packet;
}
/* Generate an ARP reply */
arphdr->ar_op = htons ( ARPOP_REPLY );
memswap ( arp_sender_pa ( arphdr ), arp_target_pa ( arphdr ), sizeof ( struct in_addr ) );
memcpy ( arp_target_ha ( arphdr ), arp_sender_ha ( arphdr ), ETH_ALEN );
memcpy ( arp_sender_ha ( arphdr ), netdev->ll_addr, ETH_ALEN );
/* Fix up ethernet header */
ethhdr = iob_push ( iob, sizeof ( *ethhdr ) );
memcpy ( ethhdr->h_dest, ethhdr->h_source, ETH_ALEN );
memcpy ( ethhdr->h_source, netdev->ll_addr, ETH_ALEN );
netdev_tx ( netdev, iob );
continue; /* no need to free iob */
}
if ( ethhdr->h_protocol != htons ( ETH_P_IP ) ) {
goto bad_packet;
}
/* IP header */
if ( iob_len ( iob ) < sizeof ( *iphdr ) ) {
goto bad_packet;
}
iphdr = iob->data;
iob_pull ( iob, sizeof ( *iphdr ) );
if ( iphdr->protocol != IP_UDP || iphdr->dest.s_addr != source_addr.sin_addr.s_addr ) {
goto bad_packet;
}
/* UDP header */
if ( iob_len ( iob ) < sizeof ( *udphdr ) ) {
goto bad_packet;
}
udphdr = iob->data;
if ( udphdr->dest != source_addr.sin_port ) {
goto bad_packet;
}
/* Learn the remote connection details */
memcpy ( dest_eth, ethhdr->h_source, ETH_ALEN );
dest_addr.sin_addr.s_addr = iphdr->src.s_addr;
dest_addr.sin_port = udphdr->src;
/* Payload */
payload_len = ntohs ( udphdr->len );
if ( payload_len < sizeof ( *udphdr ) || payload_len > iob_len ( iob ) ) {
goto bad_packet;
}
payload_len -= sizeof ( *udphdr );
iob_pull ( iob, sizeof ( *udphdr ) );
if ( payload_len > len ) {
goto bad_packet;
}
memcpy ( buf, iob->data, payload_len );
free_iob ( iob );
return payload_len;
bad_packet:
free_iob ( iob );
}
cpu_nap();
}
}
