static int nbd_errno_to_system_errno(int err)
{
+ int ret;
switch (err) {
case NBD_SUCCESS:
- return 0;
+ ret = 0;
+ break;
case NBD_EPERM:
- return EPERM;
+ ret = EPERM;
+ break;
case NBD_EIO:
- return EIO;
+ ret = EIO;
+ break;
case NBD_ENOMEM:
- return ENOMEM;
+ ret = ENOMEM;
+ break;
case NBD_ENOSPC:
- return ENOSPC;
+ ret = ENOSPC;
+ break;
+ case NBD_ESHUTDOWN:
+ ret = ESHUTDOWN;
+ break;
default:
TRACE("Squashing unexpected error %d to EINVAL", err);
/* fallthrough */
case NBD_EINVAL:
- return EINVAL;
+ ret = EINVAL;
+ break;
}
+ return ret;
}
/* Definitions for opaque data types */
*/
+/* Discard length bytes from channel. Return -errno on failure, or
+ * the amount of bytes consumed. */
+static ssize_t drop_sync(QIOChannel *ioc, size_t size)
+{
+ ssize_t ret = 0;
+ char small[1024];
+ char *buffer;
+
+ buffer = sizeof(small) < size ? small : g_malloc(MIN(65536, size));
+ while (size > 0) {
+ ssize_t count = read_sync(ioc, buffer, MIN(65536, size));
+
+ if (count <= 0) {
+ goto cleanup;
+ }
+ assert(count <= size);
+ size -= count;
+ ret += count;
+ }
+
+ cleanup:
+ if (buffer != small) {
+ g_free(buffer);
+ }
+ return ret;
+}
+
/* Send an option request.
*
* The request is for option @opt, with @data containing @len bytes of
return 0;
}
+/* Send NBD_OPT_ABORT as a courtesy to let the server know that we are
+ * not going to attempt further negotiation. */
+static void nbd_send_opt_abort(QIOChannel *ioc)
+{
+ /* Technically, a compliant server is supposed to reply to us; but
+ * older servers disconnected instead. At any rate, we're allowed
+ * to disconnect without waiting for the server reply, so we don't
+ * even care if the request makes it to the server, let alone
+ * waiting around for whether the server replies. */
+ nbd_send_option_request(ioc, NBD_OPT_ABORT, 0, NULL, NULL);
+}
+
+
/* Receive the header of an option reply, which should match the given
* opt. Read through the length field, but NOT the length bytes of
* payload. Return 0 if successful, -1 with errp set if it is
QEMU_BUILD_BUG_ON(sizeof(*reply) != 20);
if (read_sync(ioc, reply, sizeof(*reply)) != sizeof(*reply)) {
error_setg(errp, "failed to read option reply");
+ nbd_send_opt_abort(ioc);
return -1;
}
be64_to_cpus(&reply->magic);
if (reply->magic != NBD_REP_MAGIC) {
error_setg(errp, "Unexpected option reply magic");
+ nbd_send_opt_abort(ioc);
return -1;
}
if (reply->option != opt) {
error_setg(errp, "Unexpected option type %x expected %x",
reply->option, opt);
+ nbd_send_opt_abort(ioc);
return -1;
}
return 0;
reply->option);
break;
+ case NBD_REP_ERR_PLATFORM:
+ error_setg(errp, "Server lacks support for option %" PRIx32,
+ reply->option);
+ break;
+
case NBD_REP_ERR_TLS_REQD:
error_setg(errp, "TLS negotiation required before option %" PRIx32,
reply->option);
break;
+ case NBD_REP_ERR_SHUTDOWN:
+ error_setg(errp, "Server shutting down before option %" PRIx32,
+ reply->option);
+ break;
+
default:
error_setg(errp, "Unknown error code when asking for option %" PRIx32,
reply->option);
cleanup:
g_free(msg);
+ if (result < 0) {
+ nbd_send_opt_abort(ioc);
+ }
return result;
}
-static int nbd_receive_list(QIOChannel *ioc, char **name, Error **errp)
+/* Process another portion of the NBD_OPT_LIST reply. Set *@match if
+ * the current reply matches @want or if the server does not support
+ * NBD_OPT_LIST, otherwise leave @match alone. Return 0 if iteration
+ * is complete, positive if more replies are expected, or negative
+ * with @errp set if an unrecoverable error occurred. */
+static int nbd_receive_list(QIOChannel *ioc, const char *want, bool *match,
+ Error **errp)
{
nbd_opt_reply reply;
uint32_t len;
uint32_t namelen;
+ char name[NBD_MAX_NAME_SIZE + 1];
int error;
- *name = NULL;
if (nbd_receive_option_reply(ioc, NBD_OPT_LIST, &reply, errp) < 0) {
return -1;
}
error = nbd_handle_reply_err(ioc, &reply, errp);
if (error <= 0) {
+ /* The server did not support NBD_OPT_LIST, so set *match on
+ * the assumption that any name will be accepted. */
+ *match = true;
return error;
}
len = reply.length;
if (reply.type == NBD_REP_ACK) {
if (len != 0) {
error_setg(errp, "length too long for option end");
+ nbd_send_opt_abort(ioc);
return -1;
}
- } else if (reply.type == NBD_REP_SERVER) {
- if (len < sizeof(namelen) || len > NBD_MAX_BUFFER_SIZE) {
- error_setg(errp, "incorrect option length %" PRIu32, len);
- return -1;
- }
- if (read_sync(ioc, &namelen, sizeof(namelen)) != sizeof(namelen)) {
- error_setg(errp, "failed to read option name length");
- return -1;
- }
- namelen = be32_to_cpu(namelen);
- len -= sizeof(namelen);
- if (len < namelen) {
- error_setg(errp, "incorrect option name length");
- return -1;
- }
- if (namelen > NBD_MAX_NAME_SIZE) {
- error_setg(errp, "export name length too long %" PRIu32, namelen);
- return -1;
- }
+ return 0;
+ } else if (reply.type != NBD_REP_SERVER) {
+ error_setg(errp, "Unexpected reply type %" PRIx32 " expected %x",
+ reply.type, NBD_REP_SERVER);
+ nbd_send_opt_abort(ioc);
+ return -1;
+ }
- *name = g_new0(char, namelen + 1);
- if (read_sync(ioc, *name, namelen) != namelen) {
- error_setg(errp, "failed to read export name");
- g_free(*name);
- *name = NULL;
+ if (len < sizeof(namelen) || len > NBD_MAX_BUFFER_SIZE) {
+ error_setg(errp, "incorrect option length %" PRIu32, len);
+ nbd_send_opt_abort(ioc);
+ return -1;
+ }
+ if (read_sync(ioc, &namelen, sizeof(namelen)) != sizeof(namelen)) {
+ error_setg(errp, "failed to read option name length");
+ nbd_send_opt_abort(ioc);
+ return -1;
+ }
+ namelen = be32_to_cpu(namelen);
+ len -= sizeof(namelen);
+ if (len < namelen) {
+ error_setg(errp, "incorrect option name length");
+ nbd_send_opt_abort(ioc);
+ return -1;
+ }
+ if (namelen != strlen(want)) {
+ if (drop_sync(ioc, len) != len) {
+ error_setg(errp, "failed to skip export name with wrong length");
+ nbd_send_opt_abort(ioc);
return -1;
}
- (*name)[namelen] = '\0';
- len -= namelen;
- if (len) {
- char *buf = g_malloc(len + 1);
- if (read_sync(ioc, buf, len) != len) {
- error_setg(errp, "failed to read export description");
- g_free(*name);
- g_free(buf);
- *name = NULL;
- return -1;
- }
- buf[len] = '\0';
- TRACE("Ignoring export description: %s", buf);
- g_free(buf);
- }
- } else {
- error_setg(errp, "Unexpected reply type %" PRIx32 " expected %x",
- reply.type, NBD_REP_SERVER);
+ return 1;
+ }
+
+ assert(namelen < sizeof(name));
+ if (read_sync(ioc, name, namelen) != namelen) {
+ error_setg(errp, "failed to read export name");
+ nbd_send_opt_abort(ioc);
return -1;
}
+ name[namelen] = '\0';
+ len -= namelen;
+ if (drop_sync(ioc, len) != len) {
+ error_setg(errp, "failed to read export description");
+ nbd_send_opt_abort(ioc);
+ return -1;
+ }
+ if (!strcmp(name, want)) {
+ *match = true;
+ }
return 1;
}
+/* Return -1 on failure, 0 if wantname is an available export. */
static int nbd_receive_query_exports(QIOChannel *ioc,
const char *wantname,
Error **errp)
{
bool foundExport = false;
- TRACE("Querying export list");
+ TRACE("Querying export list for '%s'", wantname);
if (nbd_send_option_request(ioc, NBD_OPT_LIST, 0, NULL, errp) < 0) {
return -1;
}
TRACE("Reading available export names");
while (1) {
- char *name = NULL;
- int ret = nbd_receive_list(ioc, &name, errp);
+ int ret = nbd_receive_list(ioc, wantname, &foundExport, errp);
if (ret < 0) {
- g_free(name);
- name = NULL;
+ /* Server gave unexpected reply */
return -1;
+ } else if (ret == 0) {
+ /* Done iterating. */
+ if (!foundExport) {
+ error_setg(errp, "No export with name '%s' available",
+ wantname);
+ nbd_send_opt_abort(ioc);
+ return -1;
+ }
+ TRACE("Found desired export name '%s'", wantname);
+ return 0;
}
- if (ret == 0) {
- /* Server doesn't support export listing, so
- * we will just assume an export with our
- * wanted name exists */
- foundExport = true;
- break;
- }
- if (name == NULL) {
- TRACE("End of export name list");
- break;
- }
- if (g_str_equal(name, wantname)) {
- foundExport = true;
- TRACE("Found desired export name '%s'", name);
- } else {
- TRACE("Ignored export name '%s'", name);
- }
- g_free(name);
}
-
- if (!foundExport) {
- error_setg(errp, "No export with name '%s' available", wantname);
- return -1;
- }
-
- return 0;
}
static QIOChannel *nbd_receive_starttls(QIOChannel *ioc,
if (reply.type != NBD_REP_ACK) {
error_setg(errp, "Server rejected request to start TLS %" PRIx32,
reply.type);
+ nbd_send_opt_abort(ioc);
return NULL;
}
if (reply.length != 0) {
error_setg(errp, "Start TLS response was not zero %" PRIu32,
reply.length);
+ nbd_send_opt_abort(ioc);
return NULL;
}
char buf[256];
uint64_t magic, s;
int rc;
+ bool zeroes = true;
TRACE("Receiving negotiation tlscreds=%p hostname=%s.",
tlscreds, hostname ? hostname : "<null>");
TRACE("Server supports fixed new style");
clientflags |= NBD_FLAG_C_FIXED_NEWSTYLE;
}
+ if (globalflags & NBD_FLAG_NO_ZEROES) {
+ zeroes = false;
+ TRACE("Server supports no zeroes");
+ clientflags |= NBD_FLAG_C_NO_ZEROES;
+ }
/* client requested flags */
clientflags = cpu_to_be32(clientflags);
if (write_sync(ioc, &clientflags, sizeof(clientflags)) !=
}
TRACE("Size is %" PRIu64 ", export flags %" PRIx16, *size, *flags);
- if (read_sync(ioc, &buf, 124) != 124) {
+ if (zeroes && drop_sync(ioc, 124) != 124) {
error_setg(errp, "Failed to read reserved block");
goto fail;
}
reply->error = nbd_errno_to_system_errno(reply->error);
+ if (reply->error == ESHUTDOWN) {
+ /* This works even on mingw which lacks a native ESHUTDOWN */
+ LOG("server shutting down");
+ return -EINVAL;
+ }
TRACE("Got reply: { magic = 0x%" PRIx32 ", .error = % " PRId32
", handle = %" PRIu64" }",
magic, reply->error, reply->handle);
projects / mirror_qemu.git / blobdiff