/* * This file is part of the Distributed Network Block Device 3 * * Copyright(c) 2011-2012 Johann Latocha * * This file may be licensed under the terms of of the * GNU General Public License Version 2 (the ``GPL''). * * Software distributed under the License is distributed * on an ``AS IS'' basis, WITHOUT WARRANTY OF ANY KIND, either * express or implied. See the GPL for the specific language * governing rights and limitations. * * You should have received a copy of the GPL along with this * program. If not, go to http://www.gnu.org/licenses/gpl.html * or write to the Free Software Foundation, Inc., * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. * */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define SOCK_PATH "/var/run/dnbd3.socket" #define SOCK_BUFFER 1000 #define DEV_LEN 15 #define MAX_DEVS 50 static int openDevices[MAX_DEVS]; static const char *optString = "f:h:i:r:d:a:cs:HV?k"; static const struct option longOpts[] = { { "file", required_argument, NULL, 'f' }, { "host", required_argument, NULL, 'h' }, { "image", required_argument, NULL, 'i' }, { "rid", required_argument, NULL, 'r' }, { "device", required_argument, NULL, 'd' }, { "ahead", required_argument, NULL, 'a' }, { "close", no_argument, NULL, 'c' }, { "switch", required_argument, NULL, 's' }, { "add", required_argument, NULL, 'adds' }, { "remove", required_argument, NULL, 'rems' }, { "help", no_argument, NULL, 'H' }, { "version", no_argument, NULL, 'V' }, { "daemon", no_argument, NULL, 'D' }, { "nofork", no_argument, NULL, 'N' }, { "kill", no_argument, NULL, 'k' }, { "user", required_argument, NULL, 'U' }, // Only used in daemon mode { 0, 0, 0, 0 } }; static int dnbd3_ioctl(const char *dev, const int command, dnbd3_ioctl_t * const msg); static void dnbd3_client_daemon(); static void dnbd3_daemon_action(int client, int argc, char **argv); static int dnbd3_daemon_ioctl(int uid, char *device, int action, const char *actionName, char *host); static char* dnbd3_daemon_open(int uid, char *host, char *image, int rid, int readAhead); static int dnbd3_daemon_send(int argc, char **argv); static void dnbd3_print_help(char *argv_0); static void dnbd3_print_version(); /** * Convert a host and port (network byte order) to printable representation. * Worst case required buffer len is 48, eg. [1234:1234:1234:1234:1234:1234:1234:1234]:12345 (+ \0) * Returns true on success, false on error */ static 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 == HOST_IP6 ) { *target++ = '['; inet_ntop( AF_INET6, host->addr, target, targetlen - 10 ); target += strlen( target ); *target++ = ']'; } else if ( host->type == HOST_IP4 ) { inet_ntop( AF_INET, host->addr, target, targetlen - 8 ); target += strlen( target ); } else { snprintf( target, targetlen, "", (int)host->type ); return false; } *target = '\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 ) ); } return true; } /** * 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 HOST_IP4 or HOST_IP6 * @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 * !! Contents of @string might be modified by this function !! */ static char parse_address(char *string, dnbd3_host_t *host) { struct in_addr v4; struct in6_addr v6; // Try IPv4 without port if ( 1 == inet_pton( AF_INET, string, &v4 ) ) { host->type = HOST_IP4; memcpy( host->addr, &v4, 4 ); host->port = htons( PORT ); return 1; } // Try IPv6 without port if ( 1 == inet_pton( AF_INET6, string, &v6 ) ) { host->type = HOST_IP6; memcpy( host->addr, &v6, 16 ); host->port = htons( PORT ); return 1; } // Scan for port char *portpos = NULL, *ptr = string; while ( *ptr ) { if ( *ptr == ':' ) portpos = ptr; ++ptr; } if ( portpos == NULL ) return 0; // No port in string // Consider IP being surrounded by [ ] 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 ); // Try IPv4 with port if ( 1 == inet_pton( AF_INET, string, &v4 ) ) { host->type = HOST_IP4; memcpy( host->addr, &v4, 4 ); return 1; } // Try IPv6 with port if ( 1 == inet_pton( AF_INET6, string, &v6 ) ) { host->type = HOST_IP6; memcpy( host->addr, &v6, 16 ); return 1; } // FAIL return 0; } static int dnbd3_get_ip(char *hostname, dnbd3_host_t *host) { if ( parse_address( hostname, host ) ) return true; // TODO: Parse port too for host names struct hostent *hent; if ( (hent = gethostbyname( hostname )) == NULL ) { printf( "Unknown host '%s'\n", hostname ); return false; } if ( hent->h_addrtype == AF_INET ) { host->type = HOST_IP4; memcpy( host->addr, hent->h_addr, 4); } else if (hent->h_addrtype == AF_INET6) { host->type = HOST_IP6; memcpy(host->addr, hent->h_addr, 16); } else { printf("FATAL: Unknown address type: %d\n", hent->h_addrtype); return false; } host->port = htons( PORT ); return true; } int main(int argc, char *argv[]) { char *dev = NULL; char host[50]; int action = -1; dnbd3_ioctl_t msg; memset( &msg, 0, sizeof(dnbd3_ioctl_t) ); msg.len = (uint16_t)sizeof(dnbd3_ioctl_t); msg.read_ahead_kb = DEFAULT_READ_AHEAD_KB; msg.host.port = htons( PORT ); msg.host.type = 0; msg.imgname = NULL; msg.use_server_provided_alts = true; int opt = 0; int longIndex = 0; opt = getopt_long( argc, argv, optString, longOpts, &longIndex ); while ( opt != -1 ) { switch ( opt ) { case 'f': break; case 'h': if ( !dnbd3_get_ip( optarg, &msg.host ) ) exit( EXIT_FAILURE ); break; case 'i': action = IOCTL_OPEN; msg.imgname = strdup( optarg ); break; case 'r': msg.rid = atoi( optarg ); break; case 'd': dev = strdup( optarg ); printf( "Device is %s\n", dev ); break; case 'a': msg.read_ahead_kb = atoi( optarg ); break; case 'c': action = IOCTL_CLOSE; break; case 's': dnbd3_get_ip( optarg, &msg.host ); action = IOCTL_SWITCH; break; case 'adds': dnbd3_get_ip( optarg, &msg.host ); action = IOCTL_ADD_SRV; break; case 'rems': dnbd3_get_ip( optarg, &msg.host ); action = IOCTL_REM_SRV; break; case 'H': dnbd3_print_help( argv[0] ); break; case 'V': dnbd3_print_version(); break; case '?': dnbd3_print_help( argv[0] ); break; case 'D': dnbd3_client_daemon(); break; } opt = getopt_long( argc, argv, optString, longOpts, &longIndex ); } // See if socket exists, if so, try to send to daemon struct stat st; if ( stat( SOCK_PATH, &st ) == 0 ) { if ( dnbd3_daemon_send( argc, argv ) ) exit( 0 ); printf( "\nFailed.\n" ); exit( 1 ); } // Direct requests // In case the client was invoked as a suid binary, change uid back to original user // when being used for direct ioctl, so that the device's permissions are taken into account if ( geteuid() == 0 ) { setgid( getgid() ); setuid( getuid() ); } host_to_string( &msg.host, host, 50 ); // close device if ( action == IOCTL_CLOSE && msg.host.type == 0 && dev && (msg.imgname == NULL )) { printf( "INFO: Closing device %s\n", dev ); if ( dnbd3_ioctl( dev, IOCTL_CLOSE, &msg ) ) exit( EXIT_SUCCESS ); printf( "Couldn't close device.\n" ); exit( EXIT_FAILURE ); } // switch host if ( (action == IOCTL_SWITCH || action == IOCTL_ADD_SRV || action == IOCTL_REM_SRV) && msg.host.type != 0 && dev && (msg.imgname == NULL )) { if ( action == IOCTL_SWITCH ) printf( "INFO: Switching device %s to %s\n", dev, host ); if ( action == IOCTL_ADD_SRV ) printf( "INFO: %s: adding %s\n", dev, host ); if ( action == IOCTL_REM_SRV ) printf( "INFO: %s: removing %s\n", dev, host ); if ( dnbd3_ioctl( dev, action, &msg ) ) exit( EXIT_SUCCESS ); printf( "Failed! Maybe the device is not connected?\n" ); exit( EXIT_FAILURE ); } // connect if ( action == IOCTL_OPEN && msg.host.type != 0 && dev && (msg.imgname != NULL )) { printf( "INFO: Connecting device %s to %s for image %s\n", dev, host, msg.imgname ); if ( dnbd3_ioctl( dev, IOCTL_OPEN, &msg ) ) exit( EXIT_SUCCESS ); printf( "ERROR: connecting device failed. Maybe it's already connected?\n" ); exit( EXIT_FAILURE ); } dnbd3_print_help( argv[0] ); exit( EXIT_FAILURE ); } static int dnbd3_ioctl(const char *dev, const int command, dnbd3_ioctl_t * const msg) { const int fd = open( dev, O_WRONLY ); if ( fd < 0 ) { printf( "open() for %s failed.\n", dev ); return false; } if ( msg != NULL && msg->imgname != NULL ) msg->imgnamelen = (uint16_t)strlen( msg->imgname ); const int ret = ioctl( fd, command, msg ); if ( ret < 0 ) { printf( "ioctl() failed.\n" ); } close( fd ); return ret >= 0; } static void dnbd3_client_daemon() { int listener, client; struct sockaddr_un addrLocal, addrRemote; char buffer[SOCK_BUFFER]; struct timeval tv; int done, ret, len; socklen_t socklen; if ( geteuid() != 0 ) { printf( "Only root can run the dnbd3-client in daemon mode!\n" ); exit( 1 ); } if ( (listener = socket( AF_UNIX, SOCK_STREAM, 0 )) == -1 ) { perror( "socket" ); exit( 1 ); } addrLocal.sun_family = AF_UNIX; snprintf( addrLocal.sun_path, sizeof(addrLocal.sun_path), "%s", SOCK_PATH ); unlink( addrLocal.sun_path ); if ( bind( listener, (struct sockaddr *)&addrLocal, sizeof(addrLocal) ) < 0 ) { perror( "bind" ); exit( 1 ); } chmod( addrLocal.sun_path, 0600 ); if ( listen( listener, 5 ) == -1 ) { perror( "listen" ); exit( 1 ); } memset( openDevices, -1, sizeof(openDevices) ); for (;;) { socklen = sizeof(addrRemote); if ( (client = accept( listener, (struct sockaddr *)&addrRemote, &socklen )) == -1 ) { printf( "accept error %d\n", (int)errno); sleep( 1 ); continue; } tv.tv_sec = 1; tv.tv_usec = 0; setsockopt( client, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv) ); setsockopt( client, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv) ); ret = recv( client, &len, sizeof(len), MSG_WAITALL ); if ( ret != sizeof(len) || len <= 0 || len + 4 > SOCK_BUFFER ) { // Leave a little room (at least one byte for the appended nullchar) printf( "Error reading length field (ret: %d, len: %d)\n", ret, len ); close( client ); continue; } done = recv( client, buffer, len, MSG_WAITALL ); if ( done != len ) { printf( "receiving payload from client failed (%d/%d)\n", done, len ); } else { buffer[len] = '\0'; char *pos = buffer, *end = buffer + len; int argc = 1; char *argv[20] = { "dnbd3-client" }; while ( pos < end && argc < 20 ) { while ( *pos == '\0' ) { if ( ++pos >= end ) break; } if ( pos >= end ) break; argv[argc++] = pos; printf("Arg %d: '%s'\n", argc, pos); while ( *pos != '\0' ) { // This will always be in bounds because of -4 above if ( ++pos >= end ) break; } } dnbd3_daemon_action( client, argc, argv ); } close( client ); } } static void dnbd3_daemon_action(int client, int argc, char **argv) { int opt = 0; int longIndex = 0; char *host = NULL, *image = NULL, *device = NULL; int rid = 0, uid = 0, killMe = false, ahead = 512; int len; int action = -1; const char *actionName = NULL; optind = 1; opt = getopt_long( argc, argv, optString, longOpts, &longIndex ); while ( opt != -1 ) { switch ( opt ) { case 'd': device = optarg; break; case 'h': host = optarg; break; case 'i': image = optarg; action = IOCTL_OPEN; actionName = "Open"; break; case 'r': rid = atoi( optarg ); break; case 'U': uid = atoi( optarg ); break; case 'c': action = IOCTL_CLOSE; actionName = "Close"; break; case 'adds': action = IOCTL_ADD_SRV; actionName = "Add Server"; break; case 'rems': action = IOCTL_REM_SRV; actionName = "Remove Server"; break; case 'a': ahead = atoi( optarg ); break; case 'k': killMe = true; break; } opt = getopt_long( argc, argv, optString, longOpts, &longIndex ); } if ( killMe ) { if ( uid != 0 ) { printf( "Ignoring kill request by user %d\n", uid ); close( client ); return; } printf( "Received kill request; exiting.\n" ); close( client ); unlink( SOCK_PATH ); exit( 0 ); } if ( (action == IOCTL_CLOSE || ((action == IOCTL_ADD_SRV || action == IOCTL_REM_SRV) && host != NULL)) && device != NULL ) { if ( dnbd3_daemon_ioctl( uid, device, action, actionName, host ) ) { len = 0; } else { len = -1; } send( client, &len, sizeof(len), 0 ); return; } if ( action == IOCTL_OPEN && host != NULL && image != NULL && rid >= 0 ) { device = dnbd3_daemon_open( uid, host, image, rid, ahead ); if ( device != NULL ) { len = strlen( device ); send( client, &len, sizeof(len), 0 ); send( client, device, len, 0 ); } else { len = -1; send( client, &len, sizeof(len), 0 ); } return; } printf( "Received a client request I cannot understand.\n" ); } static int dnbd3_daemon_ioctl(int uid, char *device, int action, const char *actionName, char *host) { int index = -1; char dev[DEV_LEN]; if ( strncmp( device, "/dev/dnbd", 9 ) == 0 ) { index = atoi( device + 9 ); } else { index = atoi( device ); } dnbd3_ioctl_t msg; memset( &msg, 0, sizeof(msg) ); msg.len = (uint16_t)sizeof(msg); if ( host != NULL ) { dnbd3_get_ip( host, &msg.host ); } if ( index < 0 || index >= MAX_DEVS ) { printf( "%s request with invalid device id %d\n", actionName, index ); return false; } snprintf( dev, DEV_LEN, "/dev/dnbd%d", index ); if ( openDevices[index] == -1 ) { printf( "%s request by %d for closed device %s\n", actionName, uid, dev ); return true; } if ( openDevices[index] != uid ) { printf( "%s: User %d cannot access %s owned by %d\n", actionName, uid, dev, openDevices[index] ); return false; } if ( dnbd3_ioctl( dev, action, &msg ) ) { printf( "%s request for device %s of user %d successful\n", actionName, dev, uid ); openDevices[index] = -1; return true; } printf( "%s: Error on device %s, requested by %d\n", actionName, dev, uid ); return false; } static char* dnbd3_daemon_open(int uid, char *host, char *image, int rid, int readAhead) { int i, sameUser = 0; struct stat st; static char dev[DEV_LEN]; printf( "Opening a device for %s on %s\n", image, host ); // Check number of open devices for (i = 0; i < MAX_DEVS; ++i) { if ( openDevices[i] == uid ) sameUser++; } if ( sameUser > 1 ) { printf( "Ignoring request by %d as there are already %d open devices for that user.\n", uid, sameUser ); return NULL ; } // Find free device for (i = 0; i < MAX_DEVS; ++i) { if ( openDevices[i] != -1 ) continue; snprintf( dev, DEV_LEN, "/dev/dnbd%d", i ); if ( stat( dev, &st ) == -1 ) { break; } // Open dnbd3_ioctl_t msg; msg.len = (uint16_t)sizeof(msg); if ( !dnbd3_get_ip( host, &msg.host ) ) { printf( "Cannot parse host address %s\n", host ); return NULL ; } msg.imgname = image; msg.imgnamelen = strlen( image ); msg.rid = rid; msg.use_server_provided_alts = true; msg.read_ahead_kb = readAhead; if ( dnbd3_ioctl( dev, IOCTL_OPEN, &msg ) ) { openDevices[i] = uid; printf( "Device %s now occupied by %d\n", dev, uid ); return dev; } printf( "ioctl to open device %s failed, trying next...\n", dev ); } // All devices in use printf( "No more free devices. All %d are in use :-(\n", i ); return NULL ; } static int dnbd3_daemon_send(int argc, char **argv) { const int uid = getuid(); int s, i, len; struct sockaddr_un remote; char buffer[SOCK_BUFFER]; if ( (s = socket( AF_UNIX, SOCK_STREAM, 0 )) == -1 ) { perror( "socket" ); return false; } remote.sun_family = AF_UNIX; snprintf( remote.sun_path, sizeof(remote.sun_path), "%s", SOCK_PATH ); if ( connect( s, (struct sockaddr *)&remote, sizeof(remote) ) == -1 ) { perror( "connect" ); close( s ); return false; } // (Re)build argument string into a single one, arguments separated by null chars char *pos = buffer; char *end = buffer + SOCK_BUFFER; pos += snprintf( pos, end - pos, "--user%c%d", (int)'\0', uid ) + 1; for (i = 1; i < argc && pos < end; ++i) { pos += snprintf( pos, end - pos, "%s", argv[i] ) + 1; } // Send len = (int)(pos - buffer); if ( send( s, &len, sizeof(len), 0 ) != sizeof(len) || send( s, buffer, len, 0 ) != len ) { perror( "Sending request to daemon failed" ); close( s ); return false; } // Read reply if ( recv( s, &len, sizeof(len), MSG_WAITALL ) != sizeof(len) ) { perror( "Reading length-field from daemon failed" ); close( s ); return false; } if ( len <= 0 ) { printf( "Daemon returned exit code %d\n", -len ); close( s ); exit( -len ); } if ( len + 4 > SOCK_BUFFER ) { printf( "Reply too long (is %d bytes)\n", len ); close( s ); return false; } if ( recv( s, buffer, len, MSG_WAITALL ) != len ) { perror( "Reading reply payload from daemon failed" ); close( s ); return false; } buffer[len] = '\0'; printf( "%s", buffer ); return true; } static void dnbd3_print_help(char *argv_0) { printf( "Version: %s\n", DNBD3_VERSION ); printf( "\nUsage: %s\n" "\t-h -i [-r ] -d [-a ] || -c -d \n\n", argv_0 ); printf( "Start the DNBD3 client.\n" ); //printf("-f or --file \t\t Configuration file (default /etc/dnbd3-client.conf)\n"); printf( "-h or --host \t\t Host running dnbd3-server.\n" ); printf( "-i or --image \t\t Image name of exported image.\n" ); printf( "-r or --rid \t\t Release-ID of exported image (default 0, latest).\n" ); printf( "-d or --device \t\t DNBD3 device name.\n" ); printf( "-a or --ahead \t\t Read ahead in KByte (default %i).\n", DEFAULT_READ_AHEAD_KB ); printf( "-c or --close \t\t Disconnect and close device.\n" ); printf( "-s or --switch \t\t Switch dnbd3-server on device (DEBUG).\n" ); printf( "-H or --help \t\t Show this help text and quit.\n" ); printf( "-V or --version \t Show version and quit.\n\n" ); printf( "\t--daemon \t Run as helper daemon\n" ); printf( "\t--kill \t Kill running helper daemon\n" ); printf( "The helper daemon makes it possible for normal users to connect dnbd3 devices.\n" ); printf( "The client binary needs to be a setuid program for this to work!\n\n" ); } void dnbd3_print_version() { printf( "dnbd3-client version: %s\n", DNBD3_VERSION ); exit( EXIT_SUCCESS ); }