/* * QEMU Block driver for NBD * * Copyright (C) 2008 Bull S.A.S. * Author: Laurent Vivier <Laurent.Vivier@bull.net> * * Some parts: * Copyright (C) 2007 Anthony Liguori <anthony@codemonkey.ws> * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ #include "qemu-common.h" #include "nbd.h" #include "block_int.h" #include "module.h" #include "qemu_socket.h" #include <sys/types.h> #include <unistd.h> #define EN_OPTSTR ":exportname=" /* #define DEBUG_NBD */ #if defined(DEBUG_NBD) #define logout(fmt, ...) \ fprintf(stderr, "nbd\t%-24s" fmt, __func__, ##__VA_ARGS__) #else #define logout(fmt, ...) ((void)0) #endif typedef struct BDRVNBDState { int sock; uint32_t nbdflags; off_t size; size_t blocksize; char *export_name; /* An NBD server may export several devices */ /* If it begins with '/', this is a UNIX domain socket. Otherwise, * it's a string of the form <hostname|ip4|\[ip6\]>:port */ char *host_spec; } BDRVNBDState; static int nbd_config(BDRVNBDState *s, const char *filename, int flags) { char *file; char *export_name; const char *host_spec; const char *unixpath; int err = -EINVAL; file = g_strdup(filename); export_name = strstr(file, EN_OPTSTR); if (export_name) { if (export_name[strlen(EN_OPTSTR)] == 0) { goto out; } export_name[0] = 0; /* truncate 'file' */ export_name += strlen(EN_OPTSTR); s->export_name = g_strdup(export_name); } /* extract the host_spec - fail if it's not nbd:... */ if (!strstart(file, "nbd:", &host_spec)) { goto out; } /* are we a UNIX or TCP socket? */ if (strstart(host_spec, "unix:", &unixpath)) { if (unixpath[0] != '/') { /* We demand an absolute path*/ goto out; } s->host_spec = g_strdup(unixpath); } else { s->host_spec = g_strdup(host_spec); } err = 0; out: g_free(file); if (err != 0) { g_free(s->export_name); g_free(s->host_spec); } return err; } static int nbd_establish_connection(BlockDriverState *bs) { BDRVNBDState *s = bs->opaque; int sock; int ret; off_t size; size_t blocksize; if (s->host_spec[0] == '/') { sock = unix_socket_outgoing(s->host_spec); } else { sock = tcp_socket_outgoing_spec(s->host_spec); } /* Failed to establish connection */ if (sock == -1) { logout("Failed to establish connection to NBD server\n"); return -errno; } /* NBD handshake */ ret = nbd_receive_negotiate(sock, s->export_name, &s->nbdflags, &size, &blocksize); if (ret == -1) { logout("Failed to negotiate with the NBD server\n"); closesocket(sock); return -errno; } /* Now that we're connected, set the socket to be non-blocking */ socket_set_nonblock(sock); s->sock = sock; s->size = size; s->blocksize = blocksize; logout("Established connection with NBD server\n"); return 0; } static void nbd_teardown_connection(BlockDriverState *bs) { BDRVNBDState *s = bs->opaque; struct nbd_request request; request.type = NBD_CMD_DISC; request.handle = (uint64_t)(intptr_t)bs; request.from = 0; request.len = 0; nbd_send_request(s->sock, &request); closesocket(s->sock); } static int nbd_open(BlockDriverState *bs, const char* filename, int flags) { BDRVNBDState *s = bs->opaque; int result; /* Pop the config into our state object. Exit if invalid. */ result = nbd_config(s, filename, flags); if (result != 0) { return result; } /* establish TCP connection, return error if it fails * TODO: Configurable retry-until-timeout behaviour. */ result = nbd_establish_connection(bs); return result; } static int nbd_read(BlockDriverState *bs, int64_t sector_num, uint8_t *buf, int nb_sectors) { BDRVNBDState *s = bs->opaque; struct nbd_request request; struct nbd_reply reply; request.type = NBD_CMD_READ; request.handle = (uint64_t)(intptr_t)bs; request.from = sector_num * 512;; request.len = nb_sectors * 512; if (nbd_send_request(s->sock, &request) == -1) return -errno; if (nbd_receive_reply(s->sock, &reply) == -1) return -errno; if (reply.error !=0) return -reply.error; if (reply.handle != request.handle) return -EIO; if (nbd_wr_sync(s->sock, buf, request.len, 1) != request.len) return -EIO; return 0; } static int nbd_write(BlockDriverState *bs, int64_t sector_num, const uint8_t *buf, int nb_sectors) { BDRVNBDState *s = bs->opaque; struct nbd_request request; struct nbd_reply reply; request.type = NBD_CMD_WRITE; request.handle = (uint64_t)(intptr_t)bs; request.from = sector_num * 512;; request.len = nb_sectors * 512; if (nbd_send_request(s->sock, &request) == -1) return -errno; if (nbd_wr_sync(s->sock, (uint8_t*)buf, request.len, 0) != request.len) return -EIO; if (nbd_receive_reply(s->sock, &reply) == -1) return -errno; if (reply.error !=0) return -reply.error; if (reply.handle != request.handle) return -EIO; return 0; } static void nbd_close(BlockDriverState *bs) { BDRVNBDState *s = bs->opaque; g_free(s->export_name); g_free(s->host_spec); nbd_teardown_connection(bs); } static int64_t nbd_getlength(BlockDriverState *bs) { BDRVNBDState *s = bs->opaque; return s->size; } static BlockDriver bdrv_nbd = { .format_name = "nbd", .instance_size = sizeof(BDRVNBDState), .bdrv_file_open = nbd_open, .bdrv_read = nbd_read, .bdrv_write = nbd_write, .bdrv_close = nbd_close, .bdrv_getlength = nbd_getlength, .protocol_name = "nbd", }; static void bdrv_nbd_init(void) { bdrv_register(&bdrv_nbd); } block_init(bdrv_nbd_init);