diff options
| -rw-r--r-- | block/nbd.c | 157 |
1 files changed, 102 insertions, 55 deletions
diff --git a/block/nbd.c b/block/nbd.c index c8dc763c6b..1d6b22561b 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -29,96 +29,152 @@ #include "qemu-common.h" #include "nbd.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; 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_open(BlockDriverState *bs, const char* filename, int flags) +static int nbd_config(BDRVNBDState *s, const char *filename, int flags) { - BDRVNBDState *s = bs->opaque; - uint32_t nbdflags; - char *file; - char *name; - const char *host; + char *export_name; + const char *host_spec; const char *unixpath; - int sock; - off_t size; - size_t blocksize; - int ret; int err = -EINVAL; file = qemu_strdup(filename); - name = strstr(file, EN_OPTSTR); - if (name) { - if (name[strlen(EN_OPTSTR)] == 0) { + export_name = strstr(file, EN_OPTSTR); + if (export_name) { + if (export_name[strlen(EN_OPTSTR)] == 0) { goto out; } - name[0] = 0; - name += strlen(EN_OPTSTR); + export_name[0] = 0; /* truncate 'file' */ + export_name += strlen(EN_OPTSTR); + s->export_name = qemu_strdup(export_name); } - if (!strstart(file, "nbd:", &host)) { + /* extract the host_spec - fail if it's not nbd:... */ + if (!strstart(file, "nbd:", &host_spec)) { goto out; } - if (strstart(host, "unix:", &unixpath)) { - - if (unixpath[0] != '/') { + /* are we a UNIX or TCP socket? */ + if (strstart(host_spec, "unix:", &unixpath)) { + if (unixpath[0] != '/') { /* We demand an absolute path*/ goto out; } - - sock = unix_socket_outgoing(unixpath); - + s->host_spec = qemu_strdup(unixpath); } else { - uint16_t port = NBD_DEFAULT_PORT; - char *p, *r; - char hostname[128]; + s->host_spec = qemu_strdup(host_spec); + } - pstrcpy(hostname, 128, host); + err = 0; - p = strchr(hostname, ':'); - if (p != NULL) { - *p = '\0'; - p++; +out: + qemu_free(file); + if (err != 0) { + qemu_free(s->export_name); + qemu_free(s->host_spec); + } + return err; +} - port = strtol(p, &r, 0); - if (r == p) { - goto out; - } - } +static int nbd_establish_connection(BlockDriverState *bs) +{ + BDRVNBDState *s = bs->opaque; + int sock; + int ret; + off_t size; + size_t blocksize; + uint32_t nbdflags; - sock = tcp_socket_outgoing(hostname, port); + 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) { - err = -errno; - goto out; + logout("Failed to establish connection to NBD server\n"); + return -errno; } - ret = nbd_receive_negotiate(sock, name, &nbdflags, &size, &blocksize); + /* NBD handshake */ + ret = nbd_receive_negotiate(sock, s->export_name, &nbdflags, &size, + &blocksize); if (ret == -1) { - err = -errno; - goto out; + 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; - err = 0; -out: - qemu_free(file); - return err; + 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, @@ -183,16 +239,7 @@ static int nbd_write(BlockDriverState *bs, int64_t sector_num, static void nbd_close(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); - - close(s->sock); + nbd_teardown_connection(bs); } static int64_t nbd_getlength(BlockDriverState *bs) |