#include "integrity.h"
#include "helper.h"
#include "locks.h"
#include "image.h"
#include "uplink.h"
#include <assert.h>
#include <sys/syscall.h>
#include <sys/resource.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#define CHECK_QUEUE_SIZE 500
typedef struct
{
dnbd3_image_t *image; // Image to check
int block; // Block to check
bool full; // Check all blocks in image; .block will be increased
} 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 volatile bool 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 );
pthread_mutex_lock( &integrityQueueLock );
queueLen = 0;
pthread_mutex_unlock( &integrityQueueLock );
bRunning = true;
if ( 0 != thread_create( &thread, NULL, &integrity_main, (void *)NULL ) ) {
bRunning = false;
logadd( LOG_WARNING, "Could not start integrity check thread. Corrupted images will not be detected." );
return;
}
}
void integrity_shutdown()
{
assert( queueLen != -1 );
logadd( LOG_DEBUG1, "Shutting down integrity checker...\n" );
pthread_mutex_lock( &integrityQueueLock );
pthread_cond_signal( &queueSignal );
pthread_mutex_unlock( &integrityQueueLock );
thread_join( thread, NULL );
while ( bRunning )
usleep( 10000 );
pthread_mutex_destroy( &integrityQueueLock );
pthread_cond_destroy( &queueSignal );
logadd( LOG_DEBUG1, "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)
{
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 || checkQueue[i].full ) ) {
pthread_mutex_unlock( &integrityQueueLock );
return;
}
}
if ( freeSlot == -1 ) {
if ( queueLen >= CHECK_QUEUE_SIZE ) {
pthread_mutex_unlock( &integrityQueueLock );
logadd( LOG_DEBUG1, "Check queue full, discarding check request...\n" );
return;
}
freeSlot = queueLen++;
}
checkQueue[freeSlot].image = image;
if ( block == -1 ) {
checkQueue[freeSlot].block = 0;
checkQueue[freeSlot].full = true;
} else {
checkQueue[freeSlot].block = block;
checkQueue[freeSlot].full = false;
}
pthread_cond_signal( &queueSignal );
pthread_mutex_unlock( &integrityQueueLock );
}
static void* integrity_main(void * data UNUSED)
{
int i;
uint8_t *buffer = NULL;
size_t bufferSize = 0;
setThreadName( "image-check" );
blockNoncriticalSignals();
#if defined(linux) || defined(__linux)
// Setting nice of this thread - this is not POSIX conforming, so check if other platforms support this.
// POSIX says that setpriority() should set the nice value of all threads belonging to the current process,
// but on linux you can do this per thread.
pid_t tid = (pid_t)syscall( SYS_gettid );
setpriority( PRIO_PROCESS, tid, 10 );
#endif
pthread_mutex_lock( &integrityQueueLock );
while ( !_shutdown ) {
if ( queueLen == 0 ) {
pthread_cond_wait( &queueSignal, &integrityQueueLock );
}
for (i = queueLen - 1; i >= 0; --i) {
if ( _shutdown ) break;
dnbd3_image_t * const image = image_lock( checkQueue[i].image );
if ( !checkQueue[i].full || image == NULL ) {
checkQueue[i].image = NULL;
if ( i + 1 == queueLen ) queueLen--;
}
if ( image == NULL ) continue;
// We have the image. Call image_release() some time
bool full = checkQueue[i].full;
bool foundCorrupted = false;
spin_lock( &image->lock );
if ( image->crc32 != NULL && image->realFilesize != 0 ) {
int blocks[2] = { checkQueue[i].block, -1 };
pthread_mutex_unlock( &integrityQueueLock );
// Make copy of crc32 list as it might go away
const uint64_t fileSize = image->realFilesize;
const int numHashBlocks = IMGSIZE_TO_HASHBLOCKS(fileSize);
const size_t required = numHashBlocks * sizeof(uint32_t);
if ( buffer == NULL || required > bufferSize ) {
bufferSize = required;
if ( buffer != NULL ) free( buffer );
buffer = malloc( bufferSize );
}
memcpy( buffer, image->crc32, required );
spin_unlock( &image->lock );
// Open for direct I/O if possible; this prevents polluting the fs cache
int fd = open( image->path, O_RDONLY | O_DIRECT );
bool direct = fd != -1;
if ( unlikely( !direct ) ) {
// Try unbuffered; flush to disk for that
logadd( LOG_DEBUG1, "O_DIRECT failed for %s", image->path );
image_ensureOpen( image );
fd = image->readFd;
}
int checkCount = full ? 5 : 1;
if ( fd != -1 ) {
while ( blocks[0] < numHashBlocks && !_shutdown ) {
const uint64_t start = blocks[0] * HASH_BLOCK_SIZE;
const uint64_t end = MIN( (uint64_t)(blocks[0] + 1) * HASH_BLOCK_SIZE, image->virtualFilesize );
bool complete = true;
if ( full ) {
// When checking full image, skip incomplete blocks, otherwise assume block is complete
spin_lock( &image->lock );
complete = image_isHashBlockComplete( image->cache_map, blocks[0], fileSize );
spin_unlock( &image->lock );
}
if ( fsync( fd ) == -1 ) {
logadd( LOG_ERROR, "Cannot flush %s for integrity check", image->path );
exit( 1 );
}
// Use direct I/O only if read length is multiple of 4096 to be on the safe side
int tfd;
if ( direct && ( end % DNBD3_BLOCK_SIZE ) == 0 ) {
// Suitable for direct io
tfd = fd;
} else if ( !image_ensureOpen( image ) ) {
logadd( LOG_WARNING, "Cannot open %s for reading", image->path );
break;
} else {
tfd = image->readFd;
// Evict from cache so we have to re-read, making sure data was properly stored
posix_fadvise( fd, start, end - start, POSIX_FADV_DONTNEED );
}
if ( complete && !image_checkBlocksCrc32( tfd, (uint32_t*)buffer, blocks, fileSize ) ) {
logadd( LOG_WARNING, "Hash check for block %d of %s failed!", blocks[0], image->name );
image_updateCachemap( image, start, end, false );
// If this is not a full check, queue one
if ( !full ) {
logadd( LOG_INFO, "Queueing full check for %s", image->name );
integrity_check( image, -1 );
}
foundCorrupted = true;
}
if ( complete && --checkCount == 0 ) break;
blocks[0]++;
}
if ( direct ) {
close( fd );
}
}
pthread_mutex_lock( &integrityQueueLock );
if ( full ) {
assert( checkQueue[i].image == image );
assert( checkQueue[i].full );
if ( checkCount == 0 ) {
// Not done yet, keep going
checkQueue[i].block = blocks[0] + 1;
} else {
// Didn't check as many blocks as requested, so we must be done
checkQueue[i].image = NULL;
if ( i + 1 == queueLen ) queueLen--;
spin_lock( &image->lock );
if ( image->uplink != NULL ) { // TODO: image_determineWorkingState() helper?
image->working = image->uplink->fd != -1 && image->readFd != -1;
}
spin_unlock( &image->lock );
}
}
} else {
spin_unlock( &image->lock );
}
if ( foundCorrupted ) {
// Something was fishy, make sure uplink exists
spin_lock( &image->lock );
image->working = false;
bool restart = image->uplink == NULL || image->uplink->shutdown;
spin_unlock( &image->lock );
if ( restart ) {
uplink_shutdown( image );
uplink_init( image, -1, NULL, -1 );
}
}
// Release :-)
image_release( image );
}
}
pthread_mutex_unlock( &integrityQueueLock );
if ( buffer != NULL ) free( buffer );
bRunning = false;
return NULL ;
}
