*/
#include "qemu-common.h"
-#include "block_int.h"
-#include "nbd.h"
+#include "block/block.h"
+#include "block/nbd.h"
+#include "qemu/main-loop.h"
+#include "block/snapshot.h"
#include <stdarg.h>
#include <stdio.h>
#include <arpa/inet.h>
#include <signal.h>
#include <libgen.h>
+#include <pthread.h>
-#define SOCKET_PATH "/var/lock/qemu-nbd-%s"
-
-#define NBD_BUFFER_SIZE (1024*1024)
+#define SOCKET_PATH "/var/lock/qemu-nbd-%s"
+#define QEMU_NBD_OPT_CACHE 1
+#define QEMU_NBD_OPT_AIO 2
+#define QEMU_NBD_OPT_DISCARD 3
+static NBDExport *exp;
static int verbose;
+static char *srcpath;
+static char *sockpath;
+static int persistent = 0;
+static enum { RUNNING, TERMINATE, TERMINATING, TERMINATED } state;
+static int shared = 1;
+static int nb_fds;
static void usage(const char *name)
{
- printf(
+ (printf) (
"Usage: %s [OPTIONS] FILE\n"
"QEMU Disk Network Block Device Server\n"
"\n"
+" -h, --help display this help and exit\n"
+" -V, --version output version information and exit\n"
+"\n"
+"Connection properties:\n"
" -p, --port=PORT port to listen on (default `%d')\n"
-" -o, --offset=OFFSET offset into the image\n"
" -b, --bind=IFACE interface to bind to (default `0.0.0.0')\n"
" -k, --socket=PATH path to the unix socket\n"
" (default '"SOCKET_PATH"')\n"
-" -r, --read-only export read-only\n"
-" -P, --partition=NUM only expose partition NUM\n"
-" -s, --snapshot use snapshot file\n"
-" -n, --nocache disable host cache\n"
-" -c, --connect=DEV connect FILE to the local NBD device DEV\n"
-" -d, --disconnect disconnect the specified device\n"
" -e, --shared=NUM device can be shared by NUM clients (default '1')\n"
" -t, --persistent don't exit on the last connection\n"
" -v, --verbose display extra debugging information\n"
-" -h, --help display this help and exit\n"
-" -V, --version output version information and exit\n"
"\n"
+"Exposing part of the image:\n"
+" -o, --offset=OFFSET offset into the image\n"
+" -P, --partition=NUM only expose partition NUM\n"
+"\n"
+#ifdef __linux__
+"Kernel NBD client support:\n"
+" -c, --connect=DEV connect FILE to the local NBD device DEV\n"
+" -d, --disconnect disconnect the specified device\n"
+"\n"
+#endif
+"\n"
+"Block device options:\n"
+" -f, --format=FORMAT set image format (raw, qcow2, ...)\n"
+" -r, --read-only export read-only\n"
+" -s, --snapshot use FILE as an external snapshot, create a temporary\n"
+" file with backing_file=FILE, redirect the write to\n"
+" the temporary one\n"
+" -l, --load-snapshot=SNAPSHOT_PARAM\n"
+" load an internal snapshot inside FILE and export it\n"
+" as an read-only device, SNAPSHOT_PARAM format is\n"
+" 'snapshot.id=[ID],snapshot.name=[NAME]', or\n"
+" '[ID_OR_NAME]'\n"
+" -n, --nocache disable host cache\n"
+" --cache=MODE set cache mode (none, writeback, ...)\n"
+#ifdef CONFIG_LINUX_AIO
+" --aio=MODE set AIO mode (native or threads)\n"
+#endif
+"\n"
, name, NBD_DEFAULT_PORT, "DEVICE");
}
}
if (data[510] != 0x55 || data[511] != 0xaa) {
- errno = -EINVAL;
- return -1;
+ return -EINVAL;
}
for (i = 0; i < 4; i++) {
}
}
- errno = -ENOENT;
- return -1;
+ return -ENOENT;
}
-static void show_parts(const char *device)
+static void termsig_handler(int signum)
{
- if (fork() == 0) {
- int nbd;
+ state = TERMINATE;
+ qemu_notify_event();
+}
- /* linux just needs an open() to trigger
- * the partition table update
- * but remember to load the module with max_part != 0 :
- * modprobe nbd max_part=63
- */
- nbd = open(device, O_RDWR);
- if (nbd != -1)
- close(nbd);
- exit(0);
+static void *show_parts(void *arg)
+{
+ char *device = arg;
+ int nbd;
+
+ /* linux just needs an open() to trigger
+ * the partition table update
+ * but remember to load the module with max_part != 0 :
+ * modprobe nbd max_part=63
+ */
+ nbd = open(device, O_RDWR);
+ if (nbd >= 0) {
+ close(nbd);
+ }
+ return NULL;
+}
+
+static void *nbd_client_thread(void *arg)
+{
+ char *device = arg;
+ off_t size;
+ size_t blocksize;
+ uint32_t nbdflags;
+ int fd, sock;
+ int ret;
+ pthread_t show_parts_thread;
+
+ sock = unix_socket_outgoing(sockpath);
+ if (sock < 0) {
+ goto out;
+ }
+
+ ret = nbd_receive_negotiate(sock, NULL, &nbdflags,
+ &size, &blocksize);
+ if (ret < 0) {
+ goto out;
+ }
+
+ fd = open(device, O_RDWR);
+ if (fd < 0) {
+ /* Linux-only, we can use %m in printf. */
+ fprintf(stderr, "Failed to open %s: %m", device);
+ goto out;
+ }
+
+ ret = nbd_init(fd, sock, nbdflags, size, blocksize);
+ if (ret < 0) {
+ goto out;
+ }
+
+ /* update partition table */
+ pthread_create(&show_parts_thread, NULL, show_parts, device);
+
+ if (verbose) {
+ fprintf(stderr, "NBD device %s is now connected to %s\n",
+ device, srcpath);
+ } else {
+ /* Close stderr so that the qemu-nbd process exits. */
+ dup2(STDOUT_FILENO, STDERR_FILENO);
+ }
+
+ ret = nbd_client(fd);
+ if (ret) {
+ goto out;
+ }
+ close(fd);
+ kill(getpid(), SIGTERM);
+ return (void *) EXIT_SUCCESS;
+
+out:
+ kill(getpid(), SIGTERM);
+ return (void *) EXIT_FAILURE;
+}
+
+static int nbd_can_accept(void *opaque)
+{
+ return nb_fds < shared;
+}
+
+static void nbd_export_closed(NBDExport *exp)
+{
+ assert(state == TERMINATING);
+ state = TERMINATED;
+}
+
+static void nbd_client_closed(NBDClient *client)
+{
+ nb_fds--;
+ if (nb_fds == 0 && !persistent && state == RUNNING) {
+ state = TERMINATE;
+ }
+ qemu_notify_event();
+ nbd_client_put(client);
+}
+
+static void nbd_accept(void *opaque)
+{
+ int server_fd = (uintptr_t) opaque;
+ struct sockaddr_in addr;
+ socklen_t addr_len = sizeof(addr);
+
+ int fd = accept(server_fd, (struct sockaddr *)&addr, &addr_len);
+ if (state >= TERMINATE) {
+ close(fd);
+ return;
+ }
+
+ if (fd >= 0 && nbd_client_new(exp, fd, nbd_client_closed)) {
+ nb_fds++;
}
}
int main(int argc, char **argv)
{
BlockDriverState *bs;
+ BlockDriver *drv;
off_t dev_offset = 0;
- off_t offset = 0;
uint32_t nbdflags = 0;
bool disconnect = false;
const char *bindto = "0.0.0.0";
+ char *device = NULL;
int port = NBD_DEFAULT_PORT;
- struct sockaddr_in addr;
- socklen_t addr_len = sizeof(addr);
off_t fd_size;
- char *device = NULL;
- char *socket = NULL;
- char sockpath[128];
- const char *sopt = "hVb:o:p:rsnP:c:dvk:e:t";
+ QemuOpts *sn_opts = NULL;
+ const char *sn_id_or_name = NULL;
+ const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:";
struct option lopt[] = {
{ "help", 0, NULL, 'h' },
{ "version", 0, NULL, 'V' },
{ "connect", 1, NULL, 'c' },
{ "disconnect", 0, NULL, 'd' },
{ "snapshot", 0, NULL, 's' },
+ { "load-snapshot", 1, NULL, 'l' },
{ "nocache", 0, NULL, 'n' },
+ { "cache", 1, NULL, QEMU_NBD_OPT_CACHE },
+#ifdef CONFIG_LINUX_AIO
+ { "aio", 1, NULL, QEMU_NBD_OPT_AIO },
+#endif
+ { "discard", 1, NULL, QEMU_NBD_OPT_DISCARD },
{ "shared", 1, NULL, 'e' },
+ { "format", 1, NULL, 'f' },
{ "persistent", 0, NULL, 't' },
{ "verbose", 0, NULL, 'v' },
{ NULL, 0, NULL, 0 }
int flags = BDRV_O_RDWR;
int partition = -1;
int ret;
- int shared = 1;
- uint8_t *data;
- fd_set fds;
- int *sharing_fds;
int fd;
- int i;
- int nb_fds = 0;
- int max_fd;
- int persistent = 0;
+ bool seen_cache = false;
+ bool seen_discard = false;
+#ifdef CONFIG_LINUX_AIO
+ bool seen_aio = false;
+#endif
+ pthread_t client_thread;
+ const char *fmt = NULL;
+ Error *local_err = NULL;
+
+ /* The client thread uses SIGTERM to interrupt the server. A signal
+ * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
+ */
+ struct sigaction sa_sigterm;
+ memset(&sa_sigterm, 0, sizeof(sa_sigterm));
+ sa_sigterm.sa_handler = termsig_handler;
+ sigaction(SIGTERM, &sa_sigterm, NULL);
while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
switch (ch) {
flags |= BDRV_O_SNAPSHOT;
break;
case 'n':
- flags |= BDRV_O_NOCACHE | BDRV_O_CACHE_WB;
+ optarg = (char *) "none";
+ /* fallthrough */
+ case QEMU_NBD_OPT_CACHE:
+ if (seen_cache) {
+ errx(EXIT_FAILURE, "-n and --cache can only be specified once");
+ }
+ seen_cache = true;
+ if (bdrv_parse_cache_flags(optarg, &flags) == -1) {
+ errx(EXIT_FAILURE, "Invalid cache mode `%s'", optarg);
+ }
+ break;
+#ifdef CONFIG_LINUX_AIO
+ case QEMU_NBD_OPT_AIO:
+ if (seen_aio) {
+ errx(EXIT_FAILURE, "--aio can only be specified once");
+ }
+ seen_aio = true;
+ if (!strcmp(optarg, "native")) {
+ flags |= BDRV_O_NATIVE_AIO;
+ } else if (!strcmp(optarg, "threads")) {
+ /* this is the default */
+ } else {
+ errx(EXIT_FAILURE, "invalid aio mode `%s'", optarg);
+ }
+ break;
+#endif
+ case QEMU_NBD_OPT_DISCARD:
+ if (seen_discard) {
+ errx(EXIT_FAILURE, "--discard can only be specified once");
+ }
+ seen_discard = true;
+ if (bdrv_parse_discard_flags(optarg, &flags) == -1) {
+ errx(EXIT_FAILURE, "Invalid discard mode `%s'", optarg);
+ }
break;
case 'b':
bindto = optarg;
errx(EXIT_FAILURE, "Offset must be positive `%s'", optarg);
}
break;
+ case 'l':
+ if (strstart(optarg, SNAPSHOT_OPT_BASE, NULL)) {
+ sn_opts = qemu_opts_parse(&internal_snapshot_opts, optarg, 0);
+ if (!sn_opts) {
+ errx(EXIT_FAILURE, "Failed in parsing snapshot param `%s'",
+ optarg);
+ }
+ } else {
+ sn_id_or_name = optarg;
+ }
+ /* fall through */
case 'r':
nbdflags |= NBD_FLAG_READ_ONLY;
flags &= ~BDRV_O_RDWR;
errx(EXIT_FAILURE, "Invalid partition %d", partition);
break;
case 'k':
- socket = optarg;
- if (socket[0] != '/')
+ sockpath = optarg;
+ if (sockpath[0] != '/')
errx(EXIT_FAILURE, "socket path must be absolute\n");
break;
case 'd':
errx(EXIT_FAILURE, "Shared device number must be greater than 0\n");
}
break;
+ case 'f':
+ fmt = optarg;
+ break;
case 't':
persistent = 1;
break;
if (disconnect) {
fd = open(argv[optind], O_RDWR);
- if (fd == -1)
+ if (fd < 0) {
err(EXIT_FAILURE, "Cannot open %s", argv[optind]);
-
+ }
nbd_disconnect(fd);
close(fd);
return 0;
}
- bdrv_init();
-
- bs = bdrv_new("hda");
-
- if ((ret = bdrv_open(bs, argv[optind], flags, NULL)) < 0) {
- errno = -ret;
- err(EXIT_FAILURE, "Failed to bdrv_open '%s'", argv[optind]);
- }
-
- fd_size = bs->total_sectors * 512;
-
- if (partition != -1 &&
- find_partition(bs, partition, &dev_offset, &fd_size))
- err(EXIT_FAILURE, "Could not find partition %d", partition);
-
- if (device) {
+ if (device && !verbose) {
+ int stderr_fd[2];
pid_t pid;
- int sock;
+ int ret;
- /* want to fail before daemonizing */
- if (access(device, R_OK|W_OK) == -1) {
- err(EXIT_FAILURE, "Could not access '%s'", device);
+ if (qemu_pipe(stderr_fd) < 0) {
+ err(EXIT_FAILURE, "Error setting up communication pipe");
}
- if (!verbose) {
- /* detach client and server */
- if (qemu_daemon(0, 0) == -1) {
+ /* Now daemonize, but keep a communication channel open to
+ * print errors and exit with the proper status code.
+ */
+ pid = fork();
+ if (pid == 0) {
+ close(stderr_fd[0]);
+ ret = qemu_daemon(1, 0);
+
+ /* Temporarily redirect stderr to the parent's pipe... */
+ dup2(stderr_fd[1], STDERR_FILENO);
+ if (ret < 0) {
err(EXIT_FAILURE, "Failed to daemonize");
}
- }
- if (socket == NULL) {
- snprintf(sockpath, sizeof(sockpath), SOCKET_PATH,
- basename(device));
- socket = sockpath;
- }
-
- pid = fork();
- if (pid < 0)
- return 1;
- if (pid != 0) {
- off_t size;
- size_t blocksize;
-
- ret = 0;
- bdrv_close(bs);
-
- do {
- sock = unix_socket_outgoing(socket);
- if (sock == -1) {
- if (errno != ENOENT && errno != ECONNREFUSED) {
- ret = 1;
- goto out;
- }
- sleep(1); /* wait children */
+ /* ... close the descriptor we inherited and go on. */
+ close(stderr_fd[1]);
+ } else {
+ bool errors = false;
+ char *buf;
+
+ /* In the parent. Print error messages from the child until
+ * it closes the pipe.
+ */
+ close(stderr_fd[1]);
+ buf = g_malloc(1024);
+ while ((ret = read(stderr_fd[0], buf, 1024)) > 0) {
+ errors = true;
+ ret = qemu_write_full(STDERR_FILENO, buf, ret);
+ if (ret < 0) {
+ exit(EXIT_FAILURE);
}
- } while (sock == -1);
-
- fd = open(device, O_RDWR);
- if (fd == -1) {
- ret = 1;
- goto out;
}
-
- ret = nbd_receive_negotiate(sock, NULL, &nbdflags,
- &size, &blocksize);
- if (ret == -1) {
- ret = 1;
- goto out;
+ if (ret < 0) {
+ err(EXIT_FAILURE, "Cannot read from daemon");
}
- ret = nbd_init(fd, sock, nbdflags, size, blocksize);
- if (ret == -1) {
- ret = 1;
- goto out;
- }
+ /* Usually the daemon should not print any message.
+ * Exit with zero status in that case.
+ */
+ exit(errors);
+ }
+ }
- printf("NBD device %s is now connected to file %s\n",
- device, argv[optind]);
+ if (device != NULL && sockpath == NULL) {
+ sockpath = g_malloc(128);
+ snprintf(sockpath, 128, SOCKET_PATH, basename(device));
+ }
- /* update partition table */
+ qemu_init_main_loop();
+ bdrv_init();
+ atexit(bdrv_close_all);
- show_parts(device);
+ if (fmt) {
+ drv = bdrv_find_format(fmt);
+ if (!drv) {
+ errx(EXIT_FAILURE, "Unknown file format '%s'", fmt);
+ }
+ } else {
+ drv = NULL;
+ }
- ret = nbd_client(fd);
- if (ret) {
- ret = 1;
- }
- close(fd);
- out:
- kill(pid, SIGTERM);
- unlink(socket);
+ bs = bdrv_new("hda");
+ srcpath = argv[optind];
+ ret = bdrv_open(&bs, srcpath, NULL, NULL, flags, drv, &local_err);
+ if (ret < 0) {
+ errno = -ret;
+ err(EXIT_FAILURE, "Failed to bdrv_open '%s': %s", argv[optind],
+ error_get_pretty(local_err));
+ }
- return ret;
+ if (sn_opts) {
+ ret = bdrv_snapshot_load_tmp(bs,
+ qemu_opt_get(sn_opts, SNAPSHOT_OPT_ID),
+ qemu_opt_get(sn_opts, SNAPSHOT_OPT_NAME),
+ &local_err);
+ } else if (sn_id_or_name) {
+ ret = bdrv_snapshot_load_tmp_by_id_or_name(bs, sn_id_or_name,
+ &local_err);
+ }
+ if (ret < 0) {
+ errno = -ret;
+ err(EXIT_FAILURE,
+ "Failed to load snapshot: %s",
+ error_get_pretty(local_err));
+ }
+
+ fd_size = bdrv_getlength(bs);
+
+ if (partition != -1) {
+ ret = find_partition(bs, partition, &dev_offset, &fd_size);
+ if (ret < 0) {
+ errno = -ret;
+ err(EXIT_FAILURE, "Could not find partition %d", partition);
}
- /* children */
}
- sharing_fds = g_malloc((shared + 1) * sizeof(int));
+ exp = nbd_export_new(bs, dev_offset, fd_size, nbdflags, nbd_export_closed);
- if (socket) {
- sharing_fds[0] = unix_socket_incoming(socket);
+ if (sockpath) {
+ fd = unix_socket_incoming(sockpath);
} else {
- sharing_fds[0] = tcp_socket_incoming(bindto, port);
+ fd = tcp_socket_incoming(bindto, port);
}
- if (sharing_fds[0] == -1)
+ if (fd < 0) {
return 1;
- max_fd = sharing_fds[0];
- nb_fds++;
+ }
- data = qemu_blockalign(bs, NBD_BUFFER_SIZE);
- if (data == NULL)
- errx(EXIT_FAILURE, "Cannot allocate data buffer");
+ if (device) {
+ int ret;
- do {
+ ret = pthread_create(&client_thread, NULL, nbd_client_thread, device);
+ if (ret != 0) {
+ errx(EXIT_FAILURE, "Failed to create client thread: %s",
+ strerror(ret));
+ }
+ } else {
+ /* Shut up GCC warnings. */
+ memset(&client_thread, 0, sizeof(client_thread));
+ }
- FD_ZERO(&fds);
- for (i = 0; i < nb_fds; i++)
- FD_SET(sharing_fds[i], &fds);
+ qemu_set_fd_handler2(fd, nbd_can_accept, nbd_accept, NULL,
+ (void *)(uintptr_t)fd);
- ret = select(max_fd + 1, &fds, NULL, NULL, NULL);
- if (ret == -1)
- break;
+ /* now when the initialization is (almost) complete, chdir("/")
+ * to free any busy filesystems */
+ if (chdir("/") < 0) {
+ err(EXIT_FAILURE, "Could not chdir to root directory");
+ }
- if (FD_ISSET(sharing_fds[0], &fds))
- ret--;
- for (i = 1; i < nb_fds && ret; i++) {
- if (FD_ISSET(sharing_fds[i], &fds)) {
- if (nbd_trip(bs, sharing_fds[i], fd_size, dev_offset,
- &offset, nbdflags, data, NBD_BUFFER_SIZE) != 0) {
- close(sharing_fds[i]);
- nb_fds--;
- sharing_fds[i] = sharing_fds[nb_fds];
- i--;
- }
- ret--;
- }
- }
- /* new connection ? */
- if (FD_ISSET(sharing_fds[0], &fds)) {
- if (nb_fds < shared + 1) {
- sharing_fds[nb_fds] = accept(sharing_fds[0],
- (struct sockaddr *)&addr,
- &addr_len);
- if (sharing_fds[nb_fds] != -1 &&
- nbd_negotiate(sharing_fds[nb_fds], fd_size, nbdflags) != -1) {
- if (sharing_fds[nb_fds] > max_fd)
- max_fd = sharing_fds[nb_fds];
- nb_fds++;
- }
- }
+ state = RUNNING;
+ do {
+ main_loop_wait(false);
+ if (state == TERMINATE) {
+ state = TERMINATING;
+ nbd_export_close(exp);
+ nbd_export_put(exp);
+ exp = NULL;
}
- } while (persistent || nb_fds > 1);
- qemu_vfree(data);
+ } while (state != TERMINATED);
- close(sharing_fds[0]);
bdrv_close(bs);
- g_free(sharing_fds);
- if (socket)
- unlink(socket);
+ if (sockpath) {
+ unlink(sockpath);
+ }
+
+ if (sn_opts) {
+ qemu_opts_del(sn_opts);
+ }
- return 0;
+ if (device) {
+ void *ret;
+ pthread_join(client_thread, &ret);
+ exit(ret != NULL);
+ } else {
+ exit(EXIT_SUCCESS);
+ }
}
projects / qemu.git / blobdiff