diff --git a/qemu-nbd.c b/qemu-nbd.c index 3c538700ea..1f7b2a03f5 100644 --- a/qemu-nbd.c +++ b/qemu-nbd.c @@ -76,7 +76,8 @@ static void usage(const char *name) { (printf) ( "Usage: %s [OPTIONS] FILE\n" -"QEMU Disk Network Block Device Server\n" +" or: %s -L [OPTIONS]\n" +"QEMU Disk Network Block Device Utility\n" "\n" " -h, --help display this help and exit\n" " -V, --version output version information and exit\n" @@ -98,6 +99,7 @@ static void usage(const char *name) " -B, --bitmap=NAME expose a persistent dirty bitmap\n" "\n" "General purpose options:\n" +" -L, --list list exports available from another NBD server\n" " --object type,id=ID,... define an object such as 'secret' for providing\n" " passwords and/or encryption keys\n" " --tls-creds=ID use id of an earlier --object to provide TLS\n" @@ -131,7 +133,7 @@ static void usage(const char *name) " --image-opts treat FILE as a full set of image options\n" "\n" QEMU_HELP_BOTTOM "\n" - , name, NBD_DEFAULT_PORT, "DEVICE"); + , name, name, NBD_DEFAULT_PORT, "DEVICE"); } static void version(const char *name) @@ -243,6 +245,91 @@ static void termsig_handler(int signum) } +static int qemu_nbd_client_list(SocketAddress *saddr, QCryptoTLSCreds *tls, + const char *hostname) +{ + int ret = EXIT_FAILURE; + int rc; + Error *err = NULL; + QIOChannelSocket *sioc; + NBDExportInfo *list; + int i, j; + + sioc = qio_channel_socket_new(); + if (qio_channel_socket_connect_sync(sioc, saddr, &err) < 0) { + error_report_err(err); + return EXIT_FAILURE; + } + rc = nbd_receive_export_list(QIO_CHANNEL(sioc), tls, hostname, &list, + &err); + if (rc < 0) { + if (err) { + error_report_err(err); + } + goto out; + } + printf("exports available: %d\n", rc); + for (i = 0; i < rc; i++) { + printf(" export: '%s'\n", list[i].name); + if (list[i].description && *list[i].description) { + printf(" description: %s\n", list[i].description); + } + if (list[i].flags & NBD_FLAG_HAS_FLAGS) { + printf(" size: %" PRIu64 "\n", list[i].size); + printf(" flags: 0x%x (", list[i].flags); + if (list[i].flags & NBD_FLAG_READ_ONLY) { + printf(" readonly"); + } + if (list[i].flags & NBD_FLAG_SEND_FLUSH) { + printf(" flush"); + } + if (list[i].flags & NBD_FLAG_SEND_FUA) { + printf(" fua"); + } + if (list[i].flags & NBD_FLAG_ROTATIONAL) { + printf(" rotational"); + } + if (list[i].flags & NBD_FLAG_SEND_TRIM) { + printf(" trim"); + } + if (list[i].flags & NBD_FLAG_SEND_WRITE_ZEROES) { + printf(" zeroes"); + } + if (list[i].flags & NBD_FLAG_SEND_DF) { + printf(" df"); + } + if (list[i].flags & NBD_FLAG_CAN_MULTI_CONN) { + printf(" multi"); + } + if (list[i].flags & NBD_FLAG_SEND_RESIZE) { + printf(" resize"); + } + if (list[i].flags & NBD_FLAG_SEND_CACHE) { + printf(" cache"); + } + printf(" )\n"); + } + if (list[i].min_block) { + printf(" min block: %u\n", list[i].min_block); + printf(" opt block: %u\n", list[i].opt_block); + printf(" max block: %u\n", list[i].max_block); + } + if (list[i].n_contexts) { + printf(" available meta contexts: %d\n", list[i].n_contexts); + for (j = 0; j < list[i].n_contexts; j++) { + printf(" %s\n", list[i].contexts[j]); + } + } + } + nbd_free_export_list(list, rc); + + ret = EXIT_SUCCESS; + out: + object_unref(OBJECT(sioc)); + return ret; +} + + #if HAVE_NBD_DEVICE static void *show_parts(void *arg) { @@ -425,7 +512,8 @@ static QemuOptsList qemu_object_opts = { -static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, Error **errp) +static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, bool list, + Error **errp) { Object *obj; QCryptoTLSCreds *creds; @@ -445,10 +533,18 @@ static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, Error **errp) return NULL; } - if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) { - error_setg(errp, - "Expecting TLS credentials with a server endpoint"); - return NULL; + if (list) { + if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_CLIENT) { + error_setg(errp, + "Expecting TLS credentials with a client endpoint"); + return NULL; + } + } else { + if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) { + error_setg(errp, + "Expecting TLS credentials with a server endpoint"); + return NULL; + } } object_ref(obj); return creds; @@ -471,7 +567,8 @@ static void setup_address_and_port(const char **address, const char **port) static const char *socket_activation_validate_opts(const char *device, const char *sockpath, const char *address, - const char *port) + const char *port, + bool list) { if (device != NULL) { return "NBD device can't be set when using socket activation"; @@ -489,6 +586,10 @@ static const char *socket_activation_validate_opts(const char *device, return "TCP port number can't be set when using socket activation"; } + if (list) { + return "List mode is incompatible with socket activation"; + } + return NULL; } @@ -512,7 +613,7 @@ int main(int argc, char **argv) int64_t fd_size; QemuOpts *sn_opts = NULL; const char *sn_id_or_name = NULL; - const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:x:T:D:B:"; + const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:x:T:D:B:L"; struct option lopt[] = { { "help", no_argument, NULL, 'h' }, { "version", no_argument, NULL, 'V' }, @@ -525,6 +626,7 @@ int main(int argc, char **argv) { "bitmap", required_argument, NULL, 'B' }, { "connect", required_argument, NULL, 'c' }, { "disconnect", no_argument, NULL, 'd' }, + { "list", no_argument, NULL, 'L' }, { "snapshot", no_argument, NULL, 's' }, { "load-snapshot", required_argument, NULL, 'l' }, { "nocache", no_argument, NULL, 'n' }, @@ -559,7 +661,7 @@ int main(int argc, char **argv) Error *local_err = NULL; BlockdevDetectZeroesOptions detect_zeroes = BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF; QDict *options = NULL; - const char *export_name = ""; /* Default export name */ + const char *export_name = NULL; /* defaults to "" later for server mode */ const char *export_description = NULL; const char *bitmap = NULL; const char *tlscredsid = NULL; @@ -567,6 +669,7 @@ int main(int argc, char **argv) bool writethrough = true; char *trace_file = NULL; bool fork_process = false; + bool list = false; int old_stderr = -1; unsigned socket_activation; @@ -760,13 +863,33 @@ int main(int argc, char **argv) case QEMU_NBD_OPT_FORK: fork_process = true; break; + case 'L': + list = true; + break; } } - if ((argc - optind) != 1) { + if (list) { + if (argc != optind) { + error_report("List mode is incompatible with a file name"); + exit(EXIT_FAILURE); + } + if (export_name || export_description || dev_offset || partition || + device || disconnect || fmt || sn_id_or_name || bitmap || + seen_aio || seen_discard || seen_cache) { + error_report("List mode is incompatible with per-device settings"); + exit(EXIT_FAILURE); + } + if (fork_process) { + error_report("List mode is incompatible with forking"); + exit(EXIT_FAILURE); + } + } else if ((argc - optind) != 1) { error_report("Invalid number of arguments"); error_printf("Try `%s --help' for more information.\n", argv[0]); exit(EXIT_FAILURE); + } else if (!export_name) { + export_name = ""; } qemu_opts_foreach(&qemu_object_opts, @@ -785,7 +908,8 @@ int main(int argc, char **argv) } else { /* Using socket activation - check user didn't use -p etc. */ const char *err_msg = socket_activation_validate_opts(device, sockpath, - bindto, port); + bindto, port, + list); if (err_msg != NULL) { error_report("%s", err_msg); exit(EXIT_FAILURE); @@ -808,7 +932,7 @@ int main(int argc, char **argv) error_report("TLS is not supported with a host device"); exit(EXIT_FAILURE); } - tlscreds = nbd_get_tls_creds(tlscredsid, &local_err); + tlscreds = nbd_get_tls_creds(tlscredsid, list, &local_err); if (local_err) { error_report("Failed to get TLS creds %s", error_get_pretty(local_err)); @@ -816,6 +940,11 @@ int main(int argc, char **argv) } } + if (list) { + saddr = nbd_build_socket_address(sockpath, bindto, port); + return qemu_nbd_client_list(saddr, tlscreds, bindto); + } + #if !HAVE_NBD_DEVICE if (disconnect || device) { error_report("Kernel /dev/nbdN support not available"); diff --git a/qemu-nbd.texi b/qemu-nbd.texi index f218291bf3..386bece468 100644 --- a/qemu-nbd.texi +++ b/qemu-nbd.texi @@ -2,6 +2,8 @@ @c man begin SYNOPSIS @command{qemu-nbd} [OPTION]... @var{filename} +@command{qemu-nbd} @option{-L} [OPTION]... + @command{qemu-nbd} @option{-d} @var{dev} @c man end @end example @@ -14,6 +16,8 @@ Other uses: @itemize @item Bind a /dev/nbdX block device to a QEMU server (on Linux). +@item +As a client to query exports of a remote NBD server. @end itemize @c man end @@ -31,13 +35,15 @@ See the @code{qemu(1)} manual page for full details of the properties supported. The common object types that it makes sense to define are the @code{secret} object, which is used to supply passwords and/or encryption keys, and the @code{tls-creds} object, which is used to supply TLS -credentials for the qemu-nbd server. +credentials for the qemu-nbd server or client. @item -p, --port=@var{port} -The TCP port to listen on (default @samp{10809}). +The TCP port to listen on as a server, or connect to as a client +(default @samp{10809}). @item -o, --offset=@var{offset} The offset into the image. @item -b, --bind=@var{iface} -The interface to bind to (default @samp{0.0.0.0}). +The interface to bind to as a server, or connect to as a client +(default @samp{0.0.0.0}). @item -k, --socket=@var{path} Use a unix socket with path @var{path}. @item --image-opts @@ -97,10 +103,16 @@ Set the NBD volume export name (default of a zero-length string). @item -D, --description=@var{description} Set the NBD volume export description, as a human-readable string. +@item -L, --list +Connect as a client and list all details about the exports exposed by +a remote NBD server. This enables list mode, and is incompatible +with options that change behavior related to a specific export (such as +@option{--export-name}, @option{--offset}, ...). @item --tls-creds=ID Enable mandatory TLS encryption for the server by setting the ID of the TLS credentials object previously created with the --object -option. +option; or provide the credentials needed for connecting as a client +in list mode. @item --fork Fork off the server process and exit the parent once the server is running. @item -v, --verbose @@ -162,6 +174,15 @@ qemu-nbd -c /dev/nbd0 -f qcow2 file.qcow2 qemu-nbd -d /dev/nbd0 @end example +Query a remote server to see details about what export(s) it is +serving on port 10809, and authenticating via PSK: + +@example +qemu-nbd \ + --object tls-creds-psk,id=tls0,dir=/tmp/keys,username=eblake,endpoint=client \ + --tls-creds tls0 -L -b remote.example.com +@end example + @c man end @ignore