diff options
| -rw-r--r-- | nbd/client.c | 91 | ||||
| -rw-r--r-- | nbd/trace-events | 1 |
2 files changed, 59 insertions, 33 deletions
diff --git a/nbd/client.c b/nbd/client.c index f625c20..fd4ba8d 100644 --- a/nbd/client.c +++ b/nbd/client.c @@ -234,18 +234,24 @@ static int nbd_handle_reply_err(QIOChannel *ioc, NBDOptionReply *reply, return result; } -/* 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, +/* nbd_receive_list: + * Process another portion of the NBD_OPT_LIST reply, populating any + * name received into *@name. If @description is non-NULL, and the + * server provided a description, that is also populated. The caller + * must eventually call g_free() on success. + * Returns 1 if name and description were set and iteration must continue, + * 0 if iteration is complete (including if OPT_LIST unsupported), + * -1 with @errp set if an unrecoverable error occurred. + */ +static int nbd_receive_list(QIOChannel *ioc, char **name, char **description, Error **errp) { + int ret = -1; NBDOptionReply reply; uint32_t len; uint32_t namelen; - char name[NBD_MAX_NAME_SIZE + 1]; + char *local_name = NULL; + char *local_desc = NULL; int error; if (nbd_receive_option_reply(ioc, NBD_OPT_LIST, &reply, errp) < 0) { @@ -253,9 +259,6 @@ static int nbd_receive_list(QIOChannel *ioc, const char *want, bool *match, } 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; @@ -292,33 +295,38 @@ static int nbd_receive_list(QIOChannel *ioc, const char *want, bool *match, nbd_send_opt_abort(ioc); return -1; } - if (namelen != strlen(want)) { - if (nbd_drop(ioc, len, errp) < 0) { - error_prepend(errp, - "failed to skip export name with wrong length: "); - nbd_send_opt_abort(ioc); - return -1; - } - return 1; - } - assert(namelen < sizeof(name)); - if (nbd_read(ioc, name, namelen, errp) < 0) { + local_name = g_malloc(namelen + 1); + if (nbd_read(ioc, local_name, namelen, errp) < 0) { error_prepend(errp, "failed to read export name: "); nbd_send_opt_abort(ioc); - return -1; + goto out; } - name[namelen] = '\0'; + local_name[namelen] = '\0'; len -= namelen; - if (nbd_drop(ioc, len, errp) < 0) { - error_prepend(errp, "failed to read export description: "); - nbd_send_opt_abort(ioc); - return -1; + if (len) { + local_desc = g_malloc(len + 1); + if (nbd_read(ioc, local_desc, len, errp) < 0) { + error_prepend(errp, "failed to read export description: "); + nbd_send_opt_abort(ioc); + goto out; + } + local_desc[len] = '\0'; } - if (!strcmp(name, want)) { - *match = true; + + trace_nbd_receive_list(local_name, local_desc ?: ""); + *name = local_name; + local_name = NULL; + if (description) { + *description = local_desc; + local_desc = NULL; } - return 1; + ret = 1; + + out: + g_free(local_name); + g_free(local_desc); + return ret; } @@ -493,7 +501,8 @@ static int nbd_receive_query_exports(QIOChannel *ioc, const char *wantname, Error **errp) { - bool foundExport = false; + bool list_empty = true; + bool found_export = false; trace_nbd_receive_query_exports_start(wantname); if (nbd_send_option_request(ioc, NBD_OPT_LIST, 0, NULL, errp) < 0) { @@ -501,14 +510,25 @@ static int nbd_receive_query_exports(QIOChannel *ioc, } while (1) { - int ret = nbd_receive_list(ioc, wantname, &foundExport, errp); + char *name; + int ret = nbd_receive_list(ioc, &name, NULL, errp); if (ret < 0) { /* Server gave unexpected reply */ return -1; } else if (ret == 0) { /* Done iterating. */ - if (!foundExport) { + if (list_empty) { + /* + * We don't have enough context to tell a server that + * sent an empty list apart from a server that does + * not support the list command; but as this function + * is just used to trigger a nicer error message + * before trying NBD_OPT_EXPORT_NAME, assume the + * export is available. + */ + return 0; + } else if (!found_export) { error_setg(errp, "No export with name '%s' available", wantname); nbd_send_opt_abort(ioc); @@ -517,6 +537,11 @@ static int nbd_receive_query_exports(QIOChannel *ioc, trace_nbd_receive_query_exports_success(wantname); return 0; } + list_empty = false; + if (!strcmp(name, wantname)) { + found_export = true; + } + g_free(name); } } diff --git a/nbd/trace-events b/nbd/trace-events index 5492042..d1e1ca6 100644 --- a/nbd/trace-events +++ b/nbd/trace-events @@ -3,6 +3,7 @@ nbd_send_option_request(uint32_t opt, const char *name, uint32_t len) "Sending o nbd_receive_option_reply(uint32_t option, const char *optname, uint32_t type, const char *typename, uint32_t length) "Received option reply %" PRIu32" (%s), type %" PRIu32" (%s), len %" PRIu32 nbd_server_error_msg(uint32_t err, const char *type, const char *msg) "server reported error 0x%" PRIx32 " (%s) with additional message: %s" nbd_reply_err_unsup(uint32_t option, const char *name) "server doesn't understand request %" PRIu32 " (%s), attempting fallback" +nbd_receive_list(const char *name, const char *desc) "export list includes '%s', description '%s'" nbd_opt_go_start(const char *name) "Attempting NBD_OPT_GO for export '%s'" nbd_opt_go_success(void) "Export is good to go" nbd_opt_go_info_unknown(int info, const char *name) "Ignoring unknown info %d (%s)" |