Allow to share a disk image via nbd, by Laurent Vivier.
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@4837 c046a42c-6fe2-441c-8c8c-71466251a162
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parent
2f7264888a
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98
qemu-nbd.c
98
qemu-nbd.c
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@ -55,6 +55,7 @@ static void usage(const char *name)
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" -n, --nocache disable host cache\n"
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" -c, --connect=DEV connect FILE to the local NBD device DEV\n"
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" -d, --disconnect disconnect the specified device\n"
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" -e, --shared=NUM device can be shared by NUM clients (default '1')\n"
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" -v, --verbose display extra debugging information\n"
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" -h, --help display this help and exit\n"
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" -V, --version output version information and exit\n"
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@ -182,14 +183,13 @@ int main(int argc, char **argv)
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bool disconnect = false;
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const char *bindto = "0.0.0.0";
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int port = 1024;
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int sock, csock;
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struct sockaddr_in addr;
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socklen_t addr_len = sizeof(addr);
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off_t fd_size;
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char *device = NULL;
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char *socket = NULL;
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char sockpath[128];
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const char *sopt = "hVbo:p:rsnP:c:dvk:";
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const char *sopt = "hVbo:p:rsnP:c:dvk:e:";
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struct option lopt[] = {
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{ "help", 0, 0, 'h' },
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{ "version", 0, 0, 'V' },
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@ -203,6 +203,7 @@ int main(int argc, char **argv)
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{ "disconnect", 0, 0, 'd' },
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{ "snapshot", 0, 0, 's' },
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{ "nocache", 0, 0, 'n' },
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{ "shared", 1, 0, 'e' },
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{ "verbose", 0, 0, 'v' },
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{ NULL, 0, 0, 0 }
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};
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@ -212,9 +213,15 @@ int main(int argc, char **argv)
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char *end;
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int flags = 0;
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int partition = -1;
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int fd;
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int ret;
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int shared = 1;
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uint8_t *data;
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fd_set fds;
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int *sharing_fds;
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int fd;
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int i;
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int nb_fds = 0;
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int max_fd;
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while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
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switch (ch) {
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@ -267,6 +274,15 @@ int main(int argc, char **argv)
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case 'c':
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device = optarg;
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break;
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case 'e':
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shared = strtol(optarg, &end, 0);
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if (*end) {
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errx(EINVAL, "Invalid shared device number '%s'", optarg);
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}
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if (shared < 1) {
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errx(EINVAL, "Shared device number must be greater than 0\n");
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}
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break;
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case 'v':
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verbose = 1;
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break;
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@ -320,8 +336,10 @@ int main(int argc, char **argv)
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errx(errno, "Could not find partition %d", partition);
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if (device) {
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pid_t pid;
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if (!verbose)
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pid_t pid;
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int sock;
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if (!verbose)
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daemon(0, 0); /* detach client and server */
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if (socket == NULL) {
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@ -384,33 +402,69 @@ int main(int argc, char **argv)
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/* children */
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}
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sharing_fds = qemu_malloc((shared + 1) * sizeof(int));
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if (sharing_fds == NULL)
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errx(ENOMEM, "Cannot allocate sharing fds");
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if (socket) {
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sock = unix_socket_incoming(socket);
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sharing_fds[0] = unix_socket_incoming(socket);
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} else {
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sock = tcp_socket_incoming(bindto, port);
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sharing_fds[0] = tcp_socket_incoming(bindto, port);
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}
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if (sock == -1)
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return 1;
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csock = accept(sock,
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(struct sockaddr *)&addr,
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&addr_len);
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if (csock == -1)
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return 1;
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/* new fd_size is calculated by find_partition */
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if (nbd_negotiate(bs, csock, fd_size) == -1)
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if (sharing_fds[0] == -1)
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return 1;
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max_fd = sharing_fds[0];
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nb_fds++;
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data = qemu_memalign(512, NBD_BUFFER_SIZE);
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while (nbd_trip(bs, csock, fd_size, dev_offset, &offset, readonly,
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data, NBD_BUFFER_SIZE) == 0);
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if (data == NULL)
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errx(ENOMEM, "Cannot allocate data buffer");
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do {
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FD_ZERO(&fds);
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for (i = 0; i < nb_fds; i++)
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FD_SET(sharing_fds[i], &fds);
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ret = select(max_fd + 1, &fds, NULL, NULL, NULL);
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if (ret == -1)
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break;
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if (FD_ISSET(sharing_fds[0], &fds))
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ret--;
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for (i = 1; i < nb_fds && ret; i++) {
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if (FD_ISSET(sharing_fds[i], &fds)) {
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if (nbd_trip(bs, sharing_fds[i], fd_size, dev_offset,
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&offset, readonly, data, NBD_BUFFER_SIZE) != 0) {
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close(sharing_fds[i]);
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nb_fds--;
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sharing_fds[i] = sharing_fds[nb_fds];
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i--;
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}
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ret--;
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}
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}
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/* new connection ? */
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if (FD_ISSET(sharing_fds[0], &fds)) {
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if (nb_fds < shared + 1) {
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sharing_fds[nb_fds] = accept(sharing_fds[0],
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(struct sockaddr *)&addr,
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&addr_len);
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if (sharing_fds[nb_fds] != -1 &&
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nbd_negotiate(bs, sharing_fds[nb_fds], fd_size) != -1) {
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if (sharing_fds[nb_fds] > max_fd)
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max_fd = sharing_fds[nb_fds];
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nb_fds++;
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}
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}
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}
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} while (nb_fds > 1);
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qemu_free(data);
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close(csock);
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close(sock);
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close(sharing_fds[0]);
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bdrv_close(bs);
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qemu_free(sharing_fds);
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if (socket)
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unlink(socket);
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@ -34,6 +34,8 @@ Export Qemu disk image using NBD protocol.
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connect FILE to NBD device DEV
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@item -d, --disconnect
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disconnect the specified device
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@item -e, --shared=NUM
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device can be shared by NUM clients (default '1')
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@item -v, --verbose
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display extra debugging information
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@item -h, --help
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