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#include "connection.h"
#include "helper.h"
#include "../config.h"
#include "../shared/protocol.h"
#include "../shared/signal.h"
#include <pthread.h>
#include <string.h>
#include <stdio.h>
#include <unistd.h>
/* Constants */
static const size_t SHORTBUF = 100;
#define MAX_ALTS (8)
/* Module variables */
// Init guard
static bool initDone = false;
static pthread_mutex_t mutexInit = PTHREAD_MUTEX_INITIALIZER;
// List of pending requests
static struct {
dnbd3_async_t *head;
dnbd3_async_t *tail;
pthread_spinlock_t lock;
} requests;
// Connection for the image
static struct {
char *name;
uint16_t rid;
uint64_t size;
int sockFd;
pthread_mutex_t sendMutex;
pthread_t receiveThread;
} image;
// Known alt servers
static struct _alt_server {
} altservers[MAX_ALTS];
typedef struct _alt_server alt_server_t;
/* Static methods */
static void* connection_receiveThreadMain(void *sock);
static bool throwDataAway(int sockFd, uint32_t amount);
static void enqueueRequest(dnbd3_async_t *request);
static dnbd3_async_t* removeRequest(dnbd3_async_t *request);
bool connection_init(const char *hosts, const char *lowerImage, const uint16_t rid)
{
int sock = -1;
char host[SHORTBUF];
const char *current, *end;
serialized_buffer_t buffer;
uint16_t remoteVersion, remoteRid;
char *remoteName;
uint64_t remoteSize;
pthread_mutex_lock( &mutexInit );
if ( !initDone ) {
current = hosts;
do {
// Get next host from string
while ( *current == ' ' ) current++;
end = strchr( current, ' ' );
size_t len = (end == NULL ? SHORTBUF : (size_t)( end - current ) + 1);
if ( len > SHORTBUF ) len = SHORTBUF;
snprintf( host, len, "%s", current );
current = end + 1;
// Try to connect
sock = connect_to_server( host, PORT ); // TODO: Parse port from host
if ( sock != -1 && dnbd3_select_image( sock, lowerImage, rid, 0 )
&& dnbd3_select_image_reply( &buffer, sock, &remoteVersion, &remoteName, &remoteRid, &remoteSize )
&& ( rid == 0 || rid == remoteRid ) ) {
image.name = strdup(remoteName);
image.rid = remoteRid;
image.size = remoteSize;
break;
}
// Failed
if ( sock != -1 ) {
close( sock );
sock = -1;
}
// TODO: Add to alt list
} while ( end != NULL );
if ( sock != -1 ) {
if ( pthread_mutex_init( &image.sendMutex, NULL ) != 0
|| pthread_spin_init( &requests.lock, PTHREAD_PROCESS_PRIVATE ) != 0
|| pthread_create( &image.receiveThread, NULL, &connection_receiveThreadMain, (void*)(size_t)sock ) != 0 ) {
close( sock );
sock = -1;
} else {
image.sockFd = sock;
requests.head = NULL;
requests.tail = NULL;
}
initDone = true;
}
}
pthread_mutex_unlock( &mutexInit );
return sock != -1;
}
bool connection_read(dnbd3_async_t *request)
{
if (!initDone) return false;
enqueueRequest( request );
pthread_mutex_lock( &image.sendMutex );
if ( image.sockFd != -1 ) {
while ( !dnbd3_get_block( image.sockFd, request->offset, request->length, (uint64_t)request ) ) {
shutdown( image.sockFd, SHUT_RDWR );
image.sockFd = -1;
// TODO reconnect!
pthread_mutex_unlock( &image.sendMutex );
return false;
}
}
pthread_mutex_unlock( &image.sendMutex );
return true;
}
void connection_close()
{
//
}
static void* connection_receiveThreadMain(void *sockPtr)
{
int sockFd = (int)(size_t)sockPtr;
dnbd3_reply_t reply;
for ( ;; ) {
if ( !dnbd3_get_reply( image.sockFd, &reply ) )
goto fail;
// TODO: Ignoring anything but block replies for now; handle the others
if ( reply.cmd != CMD_GET_BLOCK ) {
if ( reply.size != 0 && !throwDataAway( sockFd, reply.size ) )
goto fail;
} else {
// get block reply. find matching request
dnbd3_async_t *request = removeRequest( (dnbd3_async_t*)reply.handle );
if ( request == NULL ) {
printf("WARNING BUG ALERT SOMETHING: Got block reply with no matching request\n");
if ( reply.size != 0 && !throwDataAway( sockFd, reply.size ) )
goto fail;
} else {
// Found a match
request->finished = true;
uint32_t done = 0;
while ( done < request->length ) {
if ( recv( sockFd, request->buffer + done, request->length - done, 0 ) <= 0 ) {
request->success = false;
signal_call( request->signalFd );
goto fail;
}
}
// Success, wake up caller
request->success = true;
signal_call( request->signalFd );
}
}
}
fail:;
// Make sure noone is trying to use the socket for sending by locking,
pthread_mutex_lock( &image.sendMutex );
// then just set the fd to -1, but only if it's the same fd as ours,
// as someone could have established a new connection already
if ( image.sockFd == sockFd ) {
image.sockFd = -1;
}
pthread_mutex_unlock( &image.sendMutex );
// As we're the only reader, it's safe to close the socket now
close( sockFd );
return NULL;
}
// Private quick helpers
static bool throwDataAway(int sockFd, uint32_t amount)
{
uint32_t done = 0;
char tempBuffer[SHORTBUF];
while ( done < amount ) {
if ( recv( sockFd, tempBuffer, MIN( amount - done, SHORTBUF ), 0 ) <= 0 )
return false;
}
return true;
}
static void enqueueRequest(dnbd3_async_t *request)
{
request->next = NULL;
request->finished = false;
request->success = false;
pthread_spin_lock( &requests.lock );
if ( requests.head == NULL ) {
requests.head = requests.tail = request;
} else {
requests.tail->next = request;
requests.tail = request;
}
pthread_spin_unlock( &requests.lock );
}
static dnbd3_async_t* removeRequest(dnbd3_async_t *request)
{
pthread_spin_lock( &requests.lock );
dnbd3_async_t *iterator, *prev = NULL;
for ( iterator = requests.head; iterator != NULL; iterator = iterator->next ) {
if ( iterator == request ) {
// Found it, break!
if ( prev != NULL ) {
prev->next = iterator->next;
}
if ( requests.tail == iterator ) {
requests.tail = prev;
}
break;
}
prev = iterator;
}
pthread_spin_unlock( &requests.lock );
return iterator;
}
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