diff options
Diffstat (limited to 'qemu-nbd.c')
-rw-r--r-- | qemu-nbd.c | 270 |
1 files changed, 223 insertions, 47 deletions
diff --git a/qemu-nbd.c b/qemu-nbd.c index ff11cdc4b..45464a0c8 100644 --- a/qemu-nbd.c +++ b/qemu-nbd.c @@ -1,4 +1,4 @@ -/*\ +/* * Copyright (C) 2005 Anthony Liguori <anthony@codemonkey.ws> * * Network Block Device @@ -21,44 +21,22 @@ #include "block_int.h" #include "nbd.h" -#include <malloc.h> #include <stdarg.h> #include <stdio.h> #include <getopt.h> #include <err.h> +#include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <netinet/tcp.h> #include <arpa/inet.h> +#include <signal.h> -int verbose; - -#ifdef _WIN32 - -void *qemu_memalign(size_t alignment, size_t size) -{ - return VirtualAlloc(NULL, size, MEM_COMMIT, PAGE_READWRITE); -} - -#else +#define SOCKET_PATH "/var/lock/qemu-nbd-%s" -void *qemu_memalign(size_t alignment, size_t size) -{ -#if defined(_POSIX_C_SOURCE) - int ret; - void *ptr; - ret = posix_memalign(&ptr, alignment, size); - if (ret != 0) - return NULL; - return ptr; -#elif defined(_BSD) - return valloc(size); -#else - return memalign(alignment, size); -#endif -} +#define NBD_BUFFER_SIZE (1024*1024) -#endif +int verbose; static void usage(const char *name) { @@ -69,14 +47,22 @@ static void usage(const char *name) " -p, --port=PORT port to listen on (default `1024')\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" "Report bugs to <anthony@codemonkey.ws>\n" - , name); + , name, "DEVICE"); } static void version(const char *name) @@ -172,41 +158,81 @@ static int find_partition(BlockDriverState *bs, int partition, return -1; } +static void show_parts(const char *device) +{ + if (fork() == 0) { + 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 != -1) + close(nbd); + exit(0); + } +} + int main(int argc, char **argv) { BlockDriverState *bs; off_t dev_offset = 0; off_t offset = 0; bool readonly = false; + bool disconnect = false; const char *bindto = "0.0.0.0"; int port = 1024; - int sock, csock; struct sockaddr_in addr; socklen_t addr_len = sizeof(addr); off_t fd_size; - const char *sopt = "hVbo:p:rsP:v"; + char *device = NULL; + char *socket = NULL; + char sockpath[128]; + const char *sopt = "hVbo:p:rsnP:c:dvk:e:t"; struct option lopt[] = { { "help", 0, 0, 'h' }, { "version", 0, 0, 'V' }, { "bind", 1, 0, 'b' }, { "port", 1, 0, 'p' }, + { "socket", 1, 0, 'k' }, { "offset", 1, 0, 'o' }, { "read-only", 0, 0, 'r' }, { "partition", 1, 0, 'P' }, + { "connect", 1, 0, 'c' }, + { "disconnect", 0, 0, 'd' }, { "snapshot", 0, 0, 's' }, + { "nocache", 0, 0, 'n' }, + { "shared", 1, 0, 'e' }, + { "persistent", 0, 0, 't' }, { "verbose", 0, 0, 'v' }, + { NULL, 0, 0, 0 } }; int ch; int opt_ind = 0; int li; char *end; - bool snapshot = false; + int flags = 0; 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; while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) { switch (ch) { case 's': - snapshot = true; + flags |= BDRV_O_SNAPSHOT; + break; + case 'n': + flags |= BDRV_O_DIRECT; break; case 'b': bindto = optarg; @@ -240,6 +266,29 @@ int main(int argc, char **argv) if (partition < 1 || partition > 8) errx(EINVAL, "Invalid partition %d", partition); break; + case 'k': + socket = optarg; + if (socket[0] != '/') + errx(EINVAL, "socket path must be absolute\n"); + break; + case 'd': + disconnect = true; + break; + case 'c': + device = optarg; + break; + case 'e': + shared = strtol(optarg, &end, 0); + if (*end) { + errx(EINVAL, "Invalid shared device number '%s'", optarg); + } + if (shared < 1) { + errx(EINVAL, "Shared device number must be greater than 0\n"); + } + break; + case 't': + persistent = 1; + break; case 'v': verbose = 1; break; @@ -263,13 +312,27 @@ int main(int argc, char **argv) argv[0]); } + if (disconnect) { + fd = open(argv[optind], O_RDWR); + if (fd == -1) + errx(errno, "Cannot open %s", argv[optind]); + + nbd_disconnect(fd); + + close(fd); + + printf("%s disconnected\n", argv[optind]); + + return 0; + } + bdrv_init(); bs = bdrv_new("hda"); if (bs == NULL) return 1; - if (bdrv_open(bs, argv[optind], snapshot) == -1) + if (bdrv_open(bs, argv[optind], flags) == -1) return 1; fd_size = bs->total_sectors * 512; @@ -278,25 +341,138 @@ int main(int argc, char **argv) find_partition(bs, partition, &dev_offset, &fd_size)) errx(errno, "Could not find partition %d", partition); - sock = tcp_socket_incoming(bindto, port); - if (sock == -1) - return 1; + if (device) { + pid_t pid; + int sock; - csock = accept(sock, - (struct sockaddr *)&addr, - &addr_len); - if (csock == -1) - return 1; + if (!verbose) + daemon(0, 0); /* detach client and server */ - /* new fd_size is calculated by find_partition */ - if (nbd_negotiate(bs, csock, fd_size) == -1) + if (socket == NULL) { + sprintf(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) + goto out; + sleep(1); /* wait children */ + } + } while (sock == -1); + + fd = open(device, O_RDWR); + if (fd == -1) { + ret = 1; + goto out; + } + + ret = nbd_receive_negotiate(sock, &size, &blocksize); + if (ret == -1) { + ret = 1; + goto out; + } + + ret = nbd_init(fd, sock, size, blocksize); + if (ret == -1) { + ret = 1; + goto out; + } + + printf("NBD device %s is now connected to file %s\n", + device, argv[optind]); + + /* update partition table */ + + show_parts(device); + + nbd_client(fd, sock); + close(fd); + out: + kill(pid, SIGTERM); + unlink(socket); + + return ret; + } + /* children */ + } + + sharing_fds = qemu_malloc((shared + 1) * sizeof(int)); + if (sharing_fds == NULL) + errx(ENOMEM, "Cannot allocate sharing fds"); + + if (socket) { + sharing_fds[0] = unix_socket_incoming(socket); + } else { + sharing_fds[0] = tcp_socket_incoming(bindto, port); + } + + if (sharing_fds[0] == -1) return 1; + max_fd = sharing_fds[0]; + nb_fds++; - while (nbd_trip(bs, csock, fd_size, dev_offset, &offset, readonly) == 0); + data = qemu_memalign(512, NBD_BUFFER_SIZE); + if (data == NULL) + errx(ENOMEM, "Cannot allocate data buffer"); + + do { + + FD_ZERO(&fds); + for (i = 0; i < nb_fds; i++) + FD_SET(sharing_fds[i], &fds); + + ret = select(max_fd + 1, &fds, NULL, NULL, NULL); + if (ret == -1) + break; + + 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, readonly, 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(bs, sharing_fds[nb_fds], fd_size) != -1) { + if (sharing_fds[nb_fds] > max_fd) + max_fd = sharing_fds[nb_fds]; + nb_fds++; + } + } + } + } while (persistent || nb_fds > 1); + qemu_free(data); - close(csock); - close(sock); + close(sharing_fds[0]); bdrv_close(bs); + qemu_free(sharing_fds); + if (socket) + unlink(socket); return 0; } |