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authorNick Thomas <nick@bytemark.co.uk>2011-02-22 15:44:54 +0000
committerKevin Wolf <kwolf@redhat.com>2011-04-07 13:51:48 +0200
commit33897dc7d62970acb731aab2ef2a65c225a8d64c (patch)
tree3ea7eb339238ac7964eef31041b5bd03c3567360 /block/nbd.c
parentc12504ceef999c80b82c69c0154205ca23247fd5 (diff)
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NBD device: Separate out parsing configuration and opening sockets.
We also change the way the file parameter is parsed so IPv6 IP addresses can be used, e.g.: "drive=nbd:[::1]:5000" Signed-off-by: Nick Thomas <nick@bytemark.co.uk> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'block/nbd.c')
-rw-r--r--block/nbd.c157
1 files changed, 102 insertions, 55 deletions
diff --git a/block/nbd.c b/block/nbd.c
index c8dc763..1d6b225 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)