From a1dd0acdbdd6a9b70f9d7aa447e323f2072c650a Mon Sep 17 00:00:00 2001
From: Simon Rettberg
Date: Mon, 12 Aug 2013 18:04:39 +0200
Subject: [SERVER] Improve proxy mode, implement integrity check in proxy mode

---
 src/server/integrity.c | 151 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 151 insertions(+)
 create mode 100644 src/server/integrity.c

(limited to 'src/server/integrity.c')

diff --git a/src/server/integrity.c b/src/server/integrity.c
new file mode 100644
index 0000000..875b62d
--- /dev/null
+++ b/src/server/integrity.c
@@ -0,0 +1,151 @@
+#include "integrity.h"
+
+#include "locks.h"
+#include "image.h"
+#include "globals.h"
+#include "memlog.h"
+
+#include <pthread.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+#include <assert.h>
+
+#define CHECK_QUEUE_SIZE 100
+
+typedef struct
+{
+	dnbd3_image_t * volatile image;
+	int volatile block;
+} queue_entry;
+
+static pthread_t thread;
+static queue_entry checkQueue[CHECK_QUEUE_SIZE];
+static pthread_mutex_t integrityQueueLock;
+static pthread_cond_t queueSignal;
+static int queueLen = -1;
+static int bRunning = FALSE;
+
+static void* integrity_main(void *data);
+
+/**
+ * Initialize the integrity check thread
+ */
+void integrity_init()
+{
+	assert( queueLen == -1 );
+	pthread_mutex_init( &integrityQueueLock, NULL );
+	pthread_cond_init( &queueSignal, NULL );
+	if ( 0 != pthread_create( &thread, NULL, &integrity_main, (void *)NULL ) ) {
+		memlogf( "[WARNING] Could not start integrity check thread. Corrupted images will not be detected." );
+		return;
+	}
+	queueLen = 0;
+}
+
+void integrity_shutdown()
+{
+	assert( queueLen != -1 );
+	printf( "[DEBUG] Shutting down integrity checker...\n" );
+	pthread_mutex_lock( &integrityQueueLock );
+	pthread_cond_signal( &queueSignal );
+	pthread_mutex_unlock( &integrityQueueLock );
+	pthread_join( thread, NULL );
+	while ( bRunning )
+		usleep( 10000 );
+	pthread_mutex_destroy( &integrityQueueLock );
+	pthread_cond_destroy( &queueSignal );
+	printf( "[DEBUG] Integrity checker exited normally.\n" );
+}
+
+/**
+ * Schedule an integrity check on the given image for the given hash block.
+ * It is not checked whether the block is completely cached locally, so
+ * make sure it is before calling, otherwise it will result in falsely
+ * detected corruption.
+ */
+void integrity_check(dnbd3_image_t *image, int block)
+{
+	printf( "Queueing %d of %s\n", block, image->lower_name );
+	int i, freeSlot = -1;
+	pthread_mutex_lock( &integrityQueueLock );
+	for (i = 0; i < queueLen; ++i) {
+		if ( freeSlot == -1 && checkQueue[i].image == NULL ) {
+			freeSlot = i;
+		} else if ( checkQueue[i].image == image && checkQueue[i].block == block ) {
+			pthread_mutex_unlock( &integrityQueueLock );
+			return;
+		}
+	}
+	if ( freeSlot == -1 ) {
+		if ( queueLen >= CHECK_QUEUE_SIZE ) {
+			pthread_mutex_unlock( &integrityQueueLock );
+			printf( "[DEBUG] Check queue full, discarding check request...\n" );
+			return;
+		}
+		freeSlot = queueLen++;
+	}
+	printf( "In slot %d\n", freeSlot );
+	checkQueue[freeSlot].image = image;
+	checkQueue[freeSlot].block = block;
+	pthread_cond_signal( &queueSignal );
+	pthread_mutex_unlock( &integrityQueueLock );
+}
+
+static void* integrity_main(void *data)
+{
+	bRunning = TRUE;
+	int i;
+	uint8_t *buffer = NULL;
+	size_t bufferSize = 0;
+	pthread_mutex_lock( &integrityQueueLock );
+	while ( !_shutdown ) {
+		for (i = queueLen - 1; i >= 0; --i) {
+			if ( checkQueue[i].image == NULL ) continue;
+			dnbd3_image_t * const image = image_lock( checkQueue[i].image );
+			checkQueue[i].image = NULL;
+			if ( image == NULL ) continue;
+			// We have the image. Call image_release() some time
+			if ( i + 1 == queueLen ) queueLen--;
+			spin_lock( &image->lock );
+			if ( image->crc32 != NULL && image->filesize != 0 ) {
+				int const blocks[2] = { checkQueue[i].block, -1 };
+				pthread_mutex_unlock( &integrityQueueLock );
+				const uint64_t fileSize = image->filesize;
+				const size_t required = IMGSIZE_TO_HASHBLOCKS(image->filesize) * sizeof(uint32_t);
+				if ( required > bufferSize ) {
+					bufferSize = required;
+					if ( buffer != NULL ) free( buffer );
+					buffer = malloc( bufferSize );
+				}
+				memcpy( buffer, image->crc32, required );
+				spin_unlock( &image->lock );
+				int fd = open( image->path, O_RDONLY );
+				if ( fd >= 0 ) {
+					if ( image_checkBlocksCrc32( fd, (uint32_t*)buffer, blocks, fileSize ) ) {
+						printf( "[DEBUG] CRC check of block %d for %s succeeded :-)\n", blocks[0], image->lower_name );
+					} else {
+						memlogf( "[WARNING] Hash check for block %d of %s failed!", blocks[0], image->lower_name );
+						image_updateCachemap( image, blocks[0] * HASH_BLOCK_SIZE, (blocks[0] + 1) * HASH_BLOCK_SIZE, FALSE );
+					}
+					close( fd );
+				}
+				pthread_mutex_lock( &integrityQueueLock );
+			} else {
+				spin_unlock( &image->lock );
+			}
+			// Release :-)
+			image_release( image );
+		}
+		if ( queueLen == 0 ) {
+			pthread_cond_wait( &queueSignal, &integrityQueueLock );
+			printf( "Queue woke up. %d jobs pending...\n", queueLen );
+		}
+	}
+	pthread_mutex_unlock( &integrityQueueLock );
+	if ( buffer != NULL ) free( buffer );
+	bRunning = FALSE;
+	return NULL ;
+}
-- 
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