[SERVER] Add command line options to create empty image of certain size with empty cache map (so it needs an uplink server)

10 files changed, 383 insertions, 191 deletions

diff --git a/src/server/altservers.c b/src/server/altservers.c
index 6301c32..44061a3 100644
--- a/src/server/altservers.c
+++ b/src/server/altservers.c
@@ -4,6 +4,7 @@
 #include "sockhelper.h"
 #include "memlog.h"
 #include "helper.h"
+#include "globals.h"
 #include <stdlib.h>
 #include <unistd.h>
 #include <sys/epoll.h>
@@ -12,6 +13,7 @@
 #include <assert.h>
 #include <inttypes.h>
 #include <time.h>
+#include <stdio.h>
 #include "../serialize.h"
 
 static dnbd3_connection_t *pending[SERVER_MAX_PENDING_ALT_CHECKS];
@@ -36,6 +38,52 @@ void altserver_init()
 	}
 }
 
+int altservers_load()
+{
+	int count = 0;
+	char *name = NULL, *space;
+	char line[1000];
+	dnbd3_host_t host;
+	asprintf( &name, "%s/%s", _configDir, "alt-servers" );
+	if ( name == NULL ) return -1;
+	FILE *fp = fopen( name, "r" );
+	free( name );
+	if ( fp == NULL ) return -1;
+	while ( !feof( fp ) ) {
+		if ( fgets( line, 1000, fp ) == NULL ) break;
+		trim_right( line );
+		space = strchr( line, ' ' );
+		if ( space != NULL ) *space++ = '\0';
+		if ( !parse_address( line, &host ) ) {
+			if ( space != NULL ) *--space = ' ';
+			memlogf( "[WARNING] Invalid entry in alt-servers file ignored: '%s'", line );
+			continue;
+		}
+		if ( altservers_add( &host, space ) ) ++count;
+	}
+	fclose( fp );
+	return count;
+}
+
+int altservers_add(dnbd3_host_t *host, const char *comment)
+{
+	int i, freeSlot = -1;
+	spin_lock( &_alts_lock );
+	for (i = 0; i < _num_alts; ++i) {
+		if ( is_same_server( &_alt_servers[i].host, host ) ) {
+			spin_unlock( &_alts_lock );
+			return FALSE;
+		} else if ( freeSlot == -1 && _alt_servers[i].host.type == 0 ) {
+			freeSlot = i;
+		}
+	}
+	if ( freeSlot == -1 ) freeSlot = _num_alts++;
+	_alt_servers[freeSlot].host = *host;
+	if ( comment != NULL ) snprintf( _alt_servers[freeSlot].comment, COMMENT_LENGTH, "%s", comment );
+	spin_unlock( &_alts_lock );
+	return TRUE;
+}
+
 /**
  * ONLY called from the passed uplink's main thread
  */
diff --git a/src/server/altservers.h b/src/server/altservers.h
index 6aec195..e080d13 100644
--- a/src/server/altservers.h
+++ b/src/server/altservers.h
@@ -5,6 +5,10 @@
 
 void altserver_init();
 
+int altservers_load();
+
+int altservers_add(dnbd3_host_t *host, const char *comment);
+
 void altserver_find_uplink(dnbd3_connection_t *uplink);
 
 int altservers_get_matching(dnbd3_host_t *host, dnbd3_server_entry_t *output, int size);
diff --git a/src/server/globals.c b/src/server/globals.c
index bfc682b..d84e3f7 100644
--- a/src/server/globals.c
+++ b/src/server/globals.c
@@ -1,7 +1,36 @@
 #include "globals.h"
+#include "ini.h"
+#include "memlog.h"
 #include "../types.h"
 #include <stddef.h>
+#include <string.h>
+#include <stdlib.h>
 
+char *_configDir = NULL;
 char *_basePath = NULL;
 int _vmdkLegacyMode = FALSE;
 int _shutdown = 0;
+
+#define SAVE_TO_VAR_STR(ss, kk) do { if (strcmp(section, #ss) == 0 && strcmp(key, #kk) == 0) { if (_ ## kk != NULL) free(_ ## kk); _ ## kk = strdup(value); } } while (0)
+#define SAVE_TO_VAR_BOOL(ss, kk) do { if (strcmp(section, #ss) == 0 && strcmp(key, #kk) == 0) _ ## kk = atoi(value) != 0 || strcmp(value, "true") == 0 || strcmp(value, "True") == 0 || strcmp(value, "TRUE") == 0; } while (0)
+#define SAVE_TO_VAR_INT(ss, kk) do { if (strcmp(section, #ss) == 0 && strcmp(key, #kk) == 0) _ ## kk = atoi(value); } while (0)
+
+static int ini_handler(void *custom, const char* section, const char* key, const char* value)
+{
+	SAVE_TO_VAR_STR( dnbd3, basePath );
+	SAVE_TO_VAR_BOOL( dnbd3, vmdkLegacyMode );
+	return TRUE;
+}
+
+void globals_loadConfig()
+{
+	char *name = NULL;
+	asprintf( &name, "%s/%s", _configDir, CONFIG_FILENAME );
+	if ( name == NULL ) return;
+	ini_parse( name, &ini_handler, NULL );
+	free( name );
+	if ( _basePath != NULL && _basePath[0] != '/' ) {
+		memlogf( "[ERROR] _basePath must be absolute!" );
+		exit( EXIT_FAILURE );
+	}
+}
diff --git a/src/server/globals.h b/src/server/globals.h
index d3424b6..2dd6e13 100644
--- a/src/server/globals.h
+++ b/src/server/globals.h
@@ -116,9 +116,14 @@ struct _dnbd3_client
 };
 
 // #######################################################
+#define CONFIG_FILENAME "server.conf"
+/**
+ * Base directory where the configuration files reside. Will never have a trailing slash.
+ */
+extern char *_configDir;
 
 /**
- * Base directory where all images are stored in. Will always have a trailing slash
+ * Base directory where all images are stored in. Will never have a trailing slash.
  */
 extern char *_basePath;
 
@@ -129,4 +134,6 @@ extern int _vmdkLegacyMode;
 
 extern int _shutdown;
 
+void globals_loadConfig();
+
 #endif /* GLOBALS_H_ */
diff --git a/src/server/helper.c b/src/server/helper.c
index dc83fb4..b028ad1 100644
--- a/src/server/helper.c
+++ b/src/server/helper.c
@@ -3,16 +3,19 @@
 #include <string.h>
 #include <stdlib.h>
 #include <fcntl.h>
+#include <assert.h>
+#include <sys/stat.h>
 #include "../types.h"
 #include "../config.h"
 
 /**
  * Parse IPv4 or IPv6 address in string representation to a suitable format usable by the BSD socket library
  * @string eg. "1.2.3.4" or "2a01::10:5", optially with port appended, eg "1.2.3.4:6666" or "[2a01::10:5]:6666"
- * @af will contain either AF_INET or AF_INET6
- * @addr will contain the address in network representation
- * @port will contain the port in network representation, defaulting to #define PORT if none was given
- * returns 1 on success, 0 in failure. contents of af, addr and port are undefined in the latter case
+ * @host pointer to dnbd3_host_t that will be filled with the following data:
+ * type will contain either AF_INET or AF_INET6
+ * addr will contain the address in network representation
+ * port will contain the port in network representation, defaulting to #define PORT if none was given
+ * returns TRUE on success, FALSE in failure. contents of af, addr and port are undefined in the latter case
  * !! Contents of @string might be modified by this function !!
  */
 char parse_address(char *string, dnbd3_host_t *host)
@@ -21,61 +24,52 @@ char parse_address(char *string, dnbd3_host_t *host)
 	struct in6_addr v6;
 
 	// Try IPv4 without port
-	if (1 == inet_pton(AF_INET, string, &v4))
-	{
+	if ( 1 == inet_pton( AF_INET, string, &v4 ) ) {
 		host->type = AF_INET;
-		memcpy(host->addr, &v4, 4);
-		host->port = htons(PORT);
-		return 1;
+		memcpy( host->addr, &v4, 4 );
+		host->port = htons( PORT );
+		return TRUE;
 	}
 	// Try IPv6 without port
-	if (1 == inet_pton(AF_INET6, string, &v6))
-	{
+	if ( 1 == inet_pton( AF_INET6, string, &v6 ) ) {
 		host->type = AF_INET6;
-		memcpy(host->addr, &v6, 16);
-		host->port = htons(PORT);
-		return 1;
+		memcpy( host->addr, &v6, 16 );
+		host->port = htons( PORT );
+		return TRUE;
 	}
 
 	// Scan for port
 	char *portpos = NULL, *ptr = string;
-	while (*ptr)
-	{
-		if (*ptr == ':')
-			portpos = ptr;
+	while ( *ptr ) {
+		if ( *ptr == ':' ) portpos = ptr;
 		++ptr;
 	}
-	if (portpos == NULL)
-		return 0; // No port in string
+	if ( portpos == NULL ) return FALSE; // No port in string
 	// Consider IP being surrounded by [ ]
-	if (*string == '[' && *(portpos - 1) == ']')
-	{
+	if ( *string == '[' && *(portpos - 1) == ']' ) {
 		++string;
 		*(portpos - 1) = '\0';
 	}
 	*portpos++ = '\0';
-	int p = atoi(portpos);
-	if (p < 1 || p > 65535)
-		return 0; // Invalid port
-	host->port = htons((uint16_t)p);
+	int p = atoi( portpos );
+	if ( p < 1 || p > 65535 ) return FALSE; // Invalid port
+	host->port = htons( (uint16_t)p );
 
 	// Try IPv4 with port
-	if (1 == inet_pton(AF_INET, string, &v4))
-	{
+	if ( 1 == inet_pton( AF_INET, string, &v4 ) ) {
 		host->type = AF_INET;
-		memcpy(host->addr, &v4, 4);
-		return 1;
+		memcpy( host->addr, &v4, 4 );
+		return TRUE;
 	}
 	// Try IPv6 with port
-	if (1 == inet_pton(AF_INET6, string, &v6))
-	{
+	if ( 1 == inet_pton( AF_INET6, string, &v6 ) ) {
 		host->type = AF_INET6;
-		memcpy(host->addr, &v6, 16);
-		return 1;
+		memcpy( host->addr, &v6, 16 );
+		return TRUE;
 	}
 
 	// FAIL
-	return 0;
+	return FALSE;
 }
 
 /**
@@ -86,110 +80,85 @@ char parse_address(char *string, dnbd3_host_t *host)
 char host_to_string(const dnbd3_host_t *host, char *target, size_t targetlen)
 {
 	// Worst case: Port 5 chars, ':' to separate ip and port 1 char, terminating null 1 char = 7, [] for IPv6
-	if (targetlen < 10)
-		return FALSE;
-	if (host->type == AF_INET6)
-	{
+	if ( targetlen < 10 ) return FALSE;
+	if ( host->type == AF_INET6 ) {
 		*target++ = '[';
-		inet_ntop(AF_INET6, host->addr, target, targetlen - 9);
-		target += strlen(target);
+		inet_ntop( AF_INET6, host->addr, target, targetlen - 9 );
+		target += strlen( target );
 		*target++ = ']';
-	}
-	else if (host->type == AF_INET)
-	{
-		inet_ntop(AF_INET, host->addr, target, targetlen - 7);
-		target += strlen(target);
-	}
-	else
-	{
-		snprintf(target, targetlen, "<?addrtype=%d>", (int)host->type);
+	} else if ( host->type == AF_INET ) {
+		inet_ntop( AF_INET, host->addr, target, targetlen - 7 );
+		target += strlen( target );
+	} else {
+		snprintf( target, targetlen, "<?addrtype=%d>", (int)host->type );
 		return FALSE;
 	}
 	*target = '\0';
-	if (host->port != 0)
-	{
+	if ( host->port != 0 ) {
 		// There are still at least 7 bytes left in the buffer, port is at most 5 bytes + ':' + '\0' = 7
-		snprintf(target, 7, ":%d", (int)ntohs(host->port));
+		snprintf( target, 7, ":%d", (int)ntohs( host->port ) );
 	}
 	return TRUE;
 }
 
-char is_valid_namespace(char *namespace)
-{
-	if (namespace == NULL || *namespace == '\0' || *namespace == '/')
-		return 0; // Invalid: Length = 0 or starting with a slash
-	while (*namespace)
-	{
-		if (*namespace != '/' && *namespace != '-' && (*namespace < 'a' || *namespace > 'z')
-		        && (*namespace < 'A' || *namespace > 'Z')
-		        && (*namespace < '0' || *namespace > '9'))
-			return 0;
-		++namespace;
-	}
-	if (strstr(namespace, "//") != NULL)
-		return 0; // Invalid: Double slash
-	if (*(namespace - 1) == '/')
-		return 0; // Invalid: Ends in a slash
-	return 1;
-}
-
-char is_valid_imagename(char *namespace)
-{
-	if (*namespace == '\0' || *namespace == ' ')
-		return 0; // Invalid: Length = 0 or starting with a space
-	while (*namespace)
-	{
-		// Check for invalid chars
-		if (*namespace != '.' && *namespace != '-' && *namespace != ' '
-		        && *namespace != '(' && *namespace != ')'
-		        && (*namespace < 'a' || *namespace > 'z') && (*namespace < 'A' || *namespace > 'Z')
-		        && (*namespace < '0' || *namespace > '9'))
-			return 0;
-		++namespace;
-	}
-	if (*(namespace - 1) == ' ')
-		return 0; // Invalid: Ends in a space
-	return 1;
-}
-
 void strtolower(char *string)
 {
-	while (*string)
-	{
-		if (*string >= 'A' && *string <= 'Z')
-			*string += 32;
+	while ( *string ) {
+		if ( *string >= 'A' && *string <= 'Z' ) *string += 32;
 		++string;
 	}
 }
 
 void remove_trailing_slash(char *string)
 {
-	char *ptr = string + strlen(string) - 1;
-	while (ptr >= string && *ptr == '/')
+	char *ptr = string + strlen( string ) - 1;
+	while ( ptr >= string && *ptr == '/' )
 		*ptr-- = '\0';
 }
 
+void trim_right(char * const string)
+{
+	char *end = string + strlen( string ) - 1;
+	while ( end >= string && (*end == '\r' || *end == '\n' || *end == ' ' || *end == '\t') )
+		*end-- = '\0';
+}
+
 int file_exists(char *file)
 {
-	int fd = open(file, O_RDONLY);
-	if (fd < 0)
-		return FALSE;
-	close(fd);
+	int fd = open( file, O_RDONLY );
+	if ( fd < 0 ) return FALSE;
+	close( fd );
 	return TRUE;
 }
 
 int file_writable(char *file)
 {
-	int fd = open(file, O_WRONLY);
-	if (fd >= 0)
-	{
-		close(fd);
+	int fd = open( file, O_WRONLY );
+	if ( fd >= 0 ) {
+		close( fd );
 		return TRUE;
 	}
-	fd = open(file, O_WRONLY | O_CREAT, 0600);
-	if (fd < 0)
-		return FALSE;
-	close(fd);
-	unlink(file);
+	fd = open( file, O_WRONLY | O_CREAT, 0600 );
+	if ( fd < 0 ) return FALSE;
+	close( fd );
+	unlink( file );
+	return TRUE;
+}
+
+int mkdir_p(const char* path)
+{
+	assert( path != NULL );
+	if ( *path == '\0' ) return TRUE;
+	char buffer[strlen( path ) + 1];
+	strcpy( buffer, path );
+	char *current = buffer;
+	char *slash;
+	while ( (slash = strchr( current, '/' )) != NULL ) {
+		*slash = '\0';
+		if ( *buffer != '\0' && mkdir( buffer, 0750 ) != 0 && errno != EEXIST ) return FALSE;
+		*slash = '/';
+		current = slash + 1;
+	}
+	if ( mkdir( buffer, 0750 ) != 0 && errno != EEXIST ) return FALSE;
 	return TRUE;
 }
diff --git a/src/server/helper.h b/src/server/helper.h
index e068abd..c212720 100644
--- a/src/server/helper.h
+++ b/src/server/helper.h
@@ -13,12 +13,12 @@
 
 char parse_address(char *string, dnbd3_host_t *host);
 char host_to_string(const dnbd3_host_t *host, char *target, size_t targetlen);
-char is_valid_namespace(char *namespace);
-char is_valid_imagename(char *namespace);
 void strtolower(char *string);
 void remove_trailing_slash(char *string);
+void trim_right(char * const string);
 int file_exists(char *file);
 int file_writable(char *file);
+int mkdir_p(const char* path);
 
 static inline int is_same_server(const dnbd3_host_t * const a, const dnbd3_host_t * const b)
 {
diff --git a/src/server/image.c b/src/server/image.c
index 2a24092..556e83b 100644
--- a/src/server/image.c
+++ b/src/server/image.c
@@ -13,6 +13,8 @@
 #include <sys/types.h>
 #include <dirent.h>
 #include <zlib.h>
+#include <inttypes.h>
+#include <fcntl.h>
 
 // ##########################################
 
@@ -25,6 +27,7 @@ pthread_spinlock_t _images_lock;
 static int image_load_all_internal(char *base, char *path);
 static int image_try_load(char *base, char *path);
 static int image_check_blocks_crc32(int fd, uint32_t *crc32list, int *blocks);
+static int64_t image_pad(const char *path, const int64_t currentSize);
 
 // ##########################################
 
@@ -388,27 +391,7 @@ static int image_try_load(char *base, char *path)
 	}
 	if ( fileSize % DNBD3_BLOCK_SIZE != 0 ) {
 		memlogf( "[INFO] Image size of '%s' is not a multiple of %d, fixing...", path, (int)DNBD3_BLOCK_SIZE );
-		const int missing = DNBD3_BLOCK_SIZE - (fileSize % DNBD3_BLOCK_SIZE);
-		char buffer[missing];
-		memset( buffer, 0, missing );
-		int tmpFd = open( path, O_WRONLY | O_APPEND );
-		int success = FALSE;
-		if ( tmpFd < 0 ) {
-			memlogf( "[WARNING] Can't open image for writing, can't fix." );
-		} else if ( lseek( tmpFd, fileSize, SEEK_SET ) != fileSize ) {
-			memlogf( "[WARNING] lseek failed, can't fix." );
-		} else if ( write( tmpFd, buffer, missing ) != missing ) {
-			memlogf( "[WARNING] write failed, can't fix." );
-		} else {
-			success = TRUE;
-		}
-		if ( tmpFd >= 0 ) close( tmpFd );
-		if ( success ) {
-			fileSize += missing;
-		} else {
-			fileSize -= (DNBD3_BLOCK_SIZE - missing);
-		}
-
+		fileSize = image_pad( path, fileSize );
 	}
 	// 1. Allocate memory for the cache map if the image is incomplete
 	sprintf( mapFile, "%s.map", path );
@@ -564,6 +547,73 @@ static int image_try_load(char *base, char *path)
 }
 
 /**
+ * Create a new image with the given image name and revision id in _basePath
+ * Returns TRUE on success, FALSE otherwise
+ */
+int image_create(char *image, int revision, uint64_t size)
+{
+	assert( image != NULL );
+	assert( size >= DNBD3_BLOCK_SIZE );
+	if ( revision <= 0 ) {
+		printf( "[ERROR] revision id invalid: %d\n", revision );
+		return FALSE;
+	}
+	const int PATHLEN = 2000;
+	char path[PATHLEN], cache[PATHLEN];
+	char *lastSlash = strrchr( image, '/' );
+	if ( lastSlash == NULL ) {
+		snprintf( path, PATHLEN, "%s/%s.r%d", _basePath, image, revision );
+	} else {
+		*lastSlash = '\0';
+		snprintf( path, PATHLEN, "%s/%s", _basePath, image );
+		mkdir_p( path );
+		*lastSlash = '/';
+		snprintf( path, PATHLEN, "%s/%s.r%d", _basePath, image, revision );
+	}
+	if ( file_exists( path ) ) {
+		printf( "[ERROR] Image %s with rid %d already exists!\n", image, revision );
+		return FALSE;
+	}
+	snprintf( cache, PATHLEN, "%s.map", path );
+	size = (size + DNBD3_BLOCK_SIZE - 1) & ~(uint64_t)(DNBD3_BLOCK_SIZE - 1);
+	const int mapsize = IMGSIZE_TO_MAPBYTES(size);
+	// Write files
+	int fdImage = -1, fdCache = -1;
+	fdImage = open( path, O_WRONLY | O_TRUNC, 0640 );
+	fdCache = open( cache, O_WRONLY | O_TRUNC, 0640 );
+	if ( fdImage < 0 ) {
+		printf( "[ERROR] Could not open %s for writing.\n", path );
+		goto failure_cleanup;
+	}
+	if ( fdCache < 0 ) {
+		printf( "[ERROR] Could not open %s for writing.\n", cache );
+		goto failure_cleanup;
+	}
+	// Try cache map first
+	if ( fallocate( fdCache, 0, 0, mapsize ) != 0 ) {
+		const int err = errno;
+		printf( "[ERROR] Could not allocate %d bytes for %s (errno=%d)", mapsize, cache, err );
+		goto failure_cleanup;
+	}
+	// Now write image
+	if ( fallocate( fdImage, 0, 0, size ) != 0 ) {
+		const int err = errno;
+		printf( "[ERROR] Could not allocate %" PRIu64 " bytes for %s (errno=%d)", size, path, err );
+		goto failure_cleanup;
+	}
+	close( fdImage );
+	close( fdCache );
+	return TRUE;
+	//
+	failure_cleanup: ;
+	if ( fdImage >= 0 ) close( fdImage );
+	if ( fdCache >= 0 ) close( fdCache );
+	remove( path );
+	remove( cache );
+	return FALSE;
+}
+
+/**
  * Generate the crc32 block list file for the given file.
  * This function wants a plain file name instead of a dnbd3_image_t,
  * as it can be used directly from the command line.
@@ -575,11 +625,35 @@ int image_generate_crc_file(char *image)
 		printf( "Could not open %s.\n", image );
 		return FALSE;
 	}
+	// force size to be multiple of DNBD3_BLOCK_SIZE
+	int64_t fileLen = lseek( fdImage, 0, SEEK_END );
+	if ( fileLen <= 0 ) {
+		printf( "Error seeking to end, or file is empty.\n" );
+		close( fdImage );
+		return FALSE;
+	}
+	if ( fileLen % DNBD3_BLOCK_SIZE != 0 ) {
+		printf( "File length is not a multiple of DNBD3_BLOCK_SIZE\n" );
+		const int64_t ret = image_pad( image, fileLen );
+		if ( ret < fileLen ) {
+			printf( "Error appending to file in order to make it block aligned.\n" );
+			close( fdImage );
+			return FALSE;
+		}
+		printf( "...fixed!\n" );
+		fileLen = ret;
+	}
+	if ( lseek( fdImage, 0, SEEK_SET ) != 0 ) {
+		printf( "Seeking back to start failed.\n" );
+		close( fdImage );
+		return FALSE;
+	}
 	char crcFile[strlen( image ) + 4 + 1];
 	sprintf( crcFile, "%s.crc", image );
 	struct stat sst;
 	if ( stat( crcFile, &sst ) == 0 ) {
 		printf( "CRC File for %s already exists! Delete it first if you want to regen.\n", image );
+		close( fdImage );
 		return FALSE;
 	}
 	int fdCrc = open( crcFile, O_RDWR | O_CREAT, 0640 );
@@ -704,6 +778,33 @@ static int image_check_blocks_crc32(int fd, uint32_t *crc32list, int *blocks)
 	return TRUE;
 }
 
+static int64_t image_pad(const char *path, const int64_t currentSize)
+{
+	const int missing = DNBD3_BLOCK_SIZE - (currentSize % DNBD3_BLOCK_SIZE );
+	char buffer[missing];
+	memset( buffer, 0, missing );
+	int tmpFd = open( path, O_WRONLY | O_APPEND );
+	int success = FALSE;
+	if ( tmpFd < 0 ) {
+		memlogf( "[WARNING] Can't open image for writing, can't fix %s", path );
+	} else if ( lseek( tmpFd, 0, SEEK_CUR ) != currentSize ) {
+		const int64_t cur = lseek( tmpFd, 0, SEEK_CUR );
+		memlogf( "[WARNING] File size of %s changed when told to extend. (is: %" PRIi64 ", should: %" PRIi64 ")", path, cur, currentSize );
+	} else if ( lseek( tmpFd, currentSize, SEEK_SET ) != currentSize ) {
+		memlogf( "[WARNING] lseek() failed, can't fix %s", path );
+	} else if ( write( tmpFd, buffer, missing ) != missing ) {
+		memlogf( "[WARNING] write() failed, can't fix %s", path );
+	} else {
+		success = TRUE;
+	}
+	if ( tmpFd >= 0 ) close( tmpFd );
+	if ( success ) {
+		return currentSize + missing;
+	} else {
+		return currentSize - (DNBD3_BLOCK_SIZE - missing);
+	}
+}
+
 /*
  void image_find_latest()
  {
diff --git a/src/server/image.h b/src/server/image.h
index 6910395..9e70e6f 100644
--- a/src/server/image.h
+++ b/src/server/image.h
@@ -10,7 +10,7 @@ extern pthread_spinlock_t _images_lock;
 
 int image_is_complete(dnbd3_image_t *image);
 
-void image_update_cachemap( dnbd3_image_t *image, uint64_t start, uint64_t end, const int set );
+void image_update_cachemap(dnbd3_image_t *image, uint64_t start, uint64_t end, const int set);
 
 int image_save_cache_map(dnbd3_image_t *image);
 
@@ -22,6 +22,7 @@ dnbd3_image_t* image_free(dnbd3_image_t *image);
 
 int image_load_all(char *path);
 
+int image_create(char *image, int revision, uint64_t size);
 
 int image_generate_crc_file(char *image);
 
diff --git a/src/server/memlog.c b/src/server/memlog.c
index f159d96..447d232 100644
--- a/src/server/memlog.c
+++ b/src/server/memlog.c
@@ -48,72 +48,75 @@ static volatile int bufferPos = 0;
 void initmemlog()
 {
 	// Use main spinlock to make sure we really init only once
-	if (logBuffer) return;
-	spin_init(&logLock, PTHREAD_PROCESS_PRIVATE);
-	logBuffer = (LogLine *)calloc(LINE_COUNT, sizeof(LogLine));
+	if ( logBuffer ) return;
+	spin_init( &logLock, PTHREAD_PROCESS_PRIVATE );
+	logBuffer = (LogLine *)calloc( LINE_COUNT, sizeof(LogLine) );
 }
 
 void memlogf(const char *fmt, ...)
 {
-	if (!logBuffer) return; // Not initialized yet
+	if ( logBuffer == NULL ) {
+		va_list ap;
+		va_start( ap, fmt );
+		vprintf( fmt, ap );
+		va_end( ap );
+		return; // Not initialized yet
+	}
 	va_list ap;
 	int ret;
 	time_t rawtime;
 	struct tm *timeinfo;
-	time(&rawtime);
-	timeinfo = localtime(&rawtime);
-	spin_lock(&logLock);
-	LogLine *const line = (LogLine *)&(logBuffer[bufferPos % LINE_COUNT]);
-	const size_t offset = strftime(line->text, LINE_LEN, "[%d.%m. %H:%M:%S] ", timeinfo);
-	if (offset == 0) *line->text = '\0';
-	va_start(ap, fmt);
-	ret = vsnprintf(line->text + offset, LINE_LEN - offset, fmt, ap);
-	va_end(ap);
-	char *end = line->text + strlen(line->text);
-	while (end > line->text && *--end == '\n') *end = '\0'; // remove trailing \n
+	time( &rawtime );
+	timeinfo = localtime( &rawtime );
+	spin_lock( &logLock );
+	LogLine * const line = (LogLine *)&(logBuffer[bufferPos % LINE_COUNT]);
+	const size_t offset = strftime( line->text, LINE_LEN, "[%d.%m. %H:%M:%S] ", timeinfo );
+	if ( offset == 0 ) *line->text = '\0';
+	va_start( ap, fmt );
+	ret = vsnprintf( line->text + offset, LINE_LEN - offset, fmt, ap );
+	va_end( ap );
+	char *end = line->text + strlen( line->text );
+	while ( end > line->text && *--end == '\n' )
+		*end = '\0'; // remove trailing \n
 	// glibc 2.0 would return -1 if the buffer was too small
 	// glibc 2.1 would return the number of bytes required if the buffer was too small
 	// so to be safe either way, let strlen do the job
-	line->len = strlen(line->text);
-	if (ret > 0 || line->len > 0) ++bufferPos;
-	spin_unlock(&logLock);
-	puts(line->text);
+	line->len = strlen( line->text );
+	if ( ret > 0 || line->len > 0 ) ++bufferPos;
+	spin_unlock( &logLock );
+	puts( line->text );
 }
 
 char *fetchlog(int maxlines)
 {
-	if (!logBuffer) return NULL;
-	if (maxlines <= 0 || maxlines > LINE_COUNT) maxlines = LINE_COUNT;
+	if ( !logBuffer ) return NULL ;
+	if ( maxlines <= 0 || maxlines > LINE_COUNT ) maxlines = LINE_COUNT;
 	const int start = MAX(0, bufferPos - maxlines);
 	int len = 1, i;
 	//printf("Outputting log from %d to %d\n", start, bufferPos);
-	spin_lock(&logLock);
+	spin_lock( &logLock );
 	// Determine required buffer space for all log lines
-	for (i = start; i < bufferPos; ++i)
-	{
-		if (logBuffer[i % LINE_COUNT].len > 0)
-		{
+	for (i = start; i < bufferPos; ++i) {
+		if ( logBuffer[i % LINE_COUNT].len > 0 ) {
 			len += logBuffer[i % LINE_COUNT].len + 1;
 		}
 	}
 	//printf("Have to allocate %d bytes\n", len);
 	// Allocate buffer. If this is a bottleneck because of malloc, consider passing a buffer to the function that the caller allocates on the stack
-	char *retval = (char *)calloc(len, sizeof(char));
-	if (retval == NULL) goto endFunction;
+	char *retval = (char *)calloc( len, sizeof(char) );
+	if ( retval == NULL ) goto endFunction;
 	// Concatenate all log lines, delimit using '\n'
 	char *pos = retval;
-	for (i = start; i < bufferPos; ++i)
-	{
-		LogLine *const line = (LogLine *)&(logBuffer[i % LINE_COUNT]);
-		if (line->len > 0)
-		{
-			memcpy(pos, (char *)line->text, line->len);
+	for (i = start; i < bufferPos; ++i) {
+		LogLine * const line = (LogLine *)&(logBuffer[i % LINE_COUNT]);
+		if ( line->len > 0 ) {
+			memcpy( pos, (char *)line->text, line->len );
 			pos += line->len;
 			*pos++ = '\n';
 		}
 	}
 	*pos = '\0';
-endFunction:
-	spin_unlock(&logLock);
+	endFunction:
+	spin_unlock( &logLock );
 	return retval;
 }
diff --git a/src/server/server.c b/src/server/server.c
index dc374a0..9b6ff30 100644
--- a/src/server/server.c
+++ b/src/server/server.c
@@ -41,6 +41,7 @@
 #include "net.h"
 #include "altservers.h"
 #include "memlog.h"
+#include "globals.h"
 
 #define MAX_SERVER_SOCKETS 50 // Assume there will be no more than 50 sockets the server will listen on
 static int sockets[MAX_SERVER_SOCKETS], socket_count = 0;
@@ -68,18 +69,20 @@ void dnbd3_print_help(char *argv_0)
 {
 	printf( "Usage: %s [OPTIONS]...\n", argv_0 );
 	printf( "Start the DNBD3 server\n" );
-	//printf( "-f or --file        Configuration file (default /etc/dnbd3-server.conf)\n" );
+	printf( "-c or --config      Configuration file (default /etc/dnbd3-server.conf)\n" );
 #ifdef _DEBUG
 	printf( "-d or --delay       Add a fake network delay of X µs\n" );
 #endif
 	printf( "-n or --nodaemon    Start server in foreground\n" );
-	printf( "-r or --reload      Reload configuration file\n" );
-	printf( "-s or --stop        Stop running dnbd3-server\n" );
-	printf( "-i or --info        Print connected clients and used images\n" );
-	printf( "-H or --help        Show this help text and quit\n" );
+	//printf( "-r or --reload      Reload configuration file\n" );
+	//printf( "-s or --stop        Stop running dnbd3-server\n" );
+	//printf( "-i or --info        Print connected clients and used images\n" );
+	printf( "-h or --help        Show this help text and quit\n" );
 	printf( "-v or --version     Show version and quit\n" );
 	printf( "Management functions:\n" );
-	printf( "--crc [image]       Generate crc block list for given image\n" );
+	printf( "--crc [image-file]  Generate crc block list for given image\n" );
+	printf( "--create [image-name] --revision [rid] --size [filesize]\n"
+			"\tCreate a local empty image file with a zeroed cache-map for the specified image" );
 	exit( 0 );
 }
 
@@ -145,17 +148,22 @@ int main(int argc, char *argv[])
 	int demonize = 1;
 	int opt = 0;
 	int longIndex = 0;
-	static const char *optString = "f:d:nrsiHV?";
-	static const struct option longOpts[] = { { "file", required_argument, NULL, 'f' }, { "delay", required_argument, NULL, 'd' }, {
+	char *paramCreate = NULL;
+	int64_t paramSize = -1;
+	int paramRevision = -1;
+	static const char *optString = "c:d:nrsihv?";
+	static const struct option longOpts[] = { { "config", required_argument, NULL, 'c' }, { "delay", required_argument, NULL, 'd' }, {
 	        "nodaemon", no_argument, NULL, 'n' }, { "reload", no_argument, NULL, 'r' }, { "stop", no_argument, NULL, 's' }, { "info",
-	        no_argument, NULL, 'i' }, { "help", no_argument, NULL, 'H' }, { "version", no_argument, NULL, 'v' }, { "crc", required_argument,
-	        NULL, 'crc4' }, { "assert", no_argument, NULL, 'asrt' }, { 0, 0, 0, 0 } };
+	        no_argument, NULL, 'i' }, { "help", no_argument, NULL, 'h' }, { "version", no_argument, NULL, 'v' }, { "crc", required_argument,
+	        NULL, 'crc4' }, { "assert", no_argument, NULL, 'asrt' }, { "create", required_argument, NULL, 'crat' }, { "revision",
+	        required_argument, NULL, 'rvid' }, { "size", required_argument, NULL, 'size' }, { 0, 0, 0, 0 } };
 
 	opt = getopt_long( argc, argv, optString, longOpts, &longIndex );
 
 	while ( opt != -1 ) {
 		switch ( opt ) {
-		case 'f':
+		case 'c':
+			_configDir = strdup( optarg );
 			break;
 		case 'd':
 #ifdef _DEBUG
@@ -180,7 +188,7 @@ int main(int argc, char *argv[])
 			printf( "INFO: Requesting information...\n\n" );
 			//dnbd3_rpc_send(RPC_IMG_LIST);
 			return EXIT_SUCCESS;
-		case 'H':
+		case 'h':
 		case '?':
 			dnbd3_print_help( argv[0] );
 			break;
@@ -194,26 +202,49 @@ int main(int argc, char *argv[])
 			assert( 4 == 5 );
 			printf( "Assertion 4 == 5 seems to hold. ;-)\n" );
 			return EXIT_SUCCESS;
+		case 'crat':
+			paramCreate = strdup( optarg );
+			break;
+		case 'rvid':
+			paramRevision = atoi( optarg );
+			break;
+		case 'size':
+			paramSize = strtoll( optarg, NULL, 10 );
+			break;
 		}
 		opt = getopt_long( argc, argv, optString, longOpts, &longIndex );
 	}
 
-	if ( demonize ) daemon( 1, 0 );
+	// One-shots first:
 
-	_basePath = strdup( "/home/sr/vmware/" );
-	_vmdkLegacyMode = TRUE;
+	if ( paramCreate != NULL ) {
+		return image_create( paramCreate, paramRevision, paramSize ) ? 0 : EXIT_FAILURE;
+	}
+
+	// No one-shot detected, normal server operation
+
+	if ( _configDir == NULL ) _configDir = strdup( "/etc/dnbd3-server" );
+	globals_loadConfig();
+	if ( _basePath == NULL ) {
+		printf( "ERROR: basePath not set in %s/%s\n", _configDir, CONFIG_FILENAME );
+		exit( EXIT_FAILURE );
+	}
 
+	if ( demonize ) daemon( 1, 0 );
+	initmemlog();
 	spin_init( &_clients_lock, PTHREAD_PROCESS_PRIVATE );
 	spin_init( &_images_lock, PTHREAD_PROCESS_PRIVATE );
 	altserver_init();
+	memlogf( "DNBD3 server starting.... Machine type: " ENDIAN_MODE );
+
+	if ( altservers_load() < 0 ) {
+		memlogf( "[WARNING] Could not load alt-servers. Does the file exist in %s?", _configDir );
+	}
 
 #ifdef _DEBUG
 	debug_locks_start_watchdog();
 #endif
 
-	initmemlog();
-	memlogf( "DNBD3 server starting.... Machine type: " ENDIAN_MODE );
-
 	// load config file
 	dnbd3_load_config();
 
@@ -235,8 +266,7 @@ int main(int argc, char *argv[])
 	if ( sockets[socket_count] != -1 ) ++socket_count;
 #ifdef WITH_IPV6
 	sockets[socket_count] = sock_listen_any(PF_INET6, PORT);
-	if (sockets[socket_count] != -1)
-	++socket_count;
+	if (sockets[socket_count] != -1) ++socket_count;
 #endif
 	if ( socket_count == 0 ) exit( EXIT_FAILURE );
 	struct sockaddr_storage client;