From a57f6dea02cdcf7733786f15bab6665ecfc1033b Mon Sep 17 00:00:00 2001 From: Eric Blake Date: Fri, 27 Oct 2017 12:40:33 +0200 Subject: [PATCH] nbd/server: Include human-readable message in structured errors The NBD spec permits including a human-readable error string if structured replies are in force, so we might as well send the client the message that we logged on any error. Signed-off-by: Eric Blake Reviewed-by: Vladimir Sementsov-Ogievskiy Message-Id: <20171027104037.8319-9-eblake@redhat.com> --- nbd/server.c | 20 +++++++++++++------- nbd/trace-events | 2 +- 2 files changed, 14 insertions(+), 8 deletions(-) diff --git a/nbd/server.c b/nbd/server.c index 3261fd1bd7..70b40ed27e 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -1296,24 +1296,25 @@ static int coroutine_fn nbd_co_send_structured_read(NBDClient *client, static int coroutine_fn nbd_co_send_structured_error(NBDClient *client, uint64_t handle, uint32_t error, + const char *msg, Error **errp) { NBDStructuredError chunk; int nbd_err = system_errno_to_nbd_errno(error); struct iovec iov[] = { {.iov_base = &chunk, .iov_len = sizeof(chunk)}, - /* FIXME: Support human-readable error message */ + {.iov_base = (char *)msg, .iov_len = msg ? strlen(msg) : 0}, }; assert(nbd_err); trace_nbd_co_send_structured_error(handle, nbd_err, - nbd_err_lookup(nbd_err)); + nbd_err_lookup(nbd_err), msg ? msg : ""); set_be_chunk(&chunk.h, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_ERROR, handle, - sizeof(chunk) - sizeof(chunk.h)); + sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len); stl_be_p(&chunk.error, nbd_err); - stw_be_p(&chunk.message_length, 0); + stw_be_p(&chunk.message_length, iov[1].iov_len); - return nbd_co_send_iov(client, iov, 1, errp); + return nbd_co_send_iov(client, iov, 1 + !!iov[1].iov_len, errp); } /* nbd_co_receive_request @@ -1414,6 +1415,7 @@ static coroutine_fn void nbd_trip(void *opaque) int flags; int reply_data_len = 0; Error *local_err = NULL; + char *msg = NULL; trace_nbd_trip(); if (client->closing) { @@ -1530,14 +1532,17 @@ reply: if (local_err) { /* If we get here, local_err was not a fatal error, and should be sent * to the client. */ + assert(ret < 0); + msg = g_strdup(error_get_pretty(local_err)); error_report_err(local_err); local_err = NULL; } - if (client->structured_reply && request.type == NBD_CMD_READ) { + if (client->structured_reply && + (ret < 0 || request.type == NBD_CMD_READ)) { if (ret < 0) { ret = nbd_co_send_structured_error(req->client, request.handle, - -ret, &local_err); + -ret, msg, &local_err); } else { ret = nbd_co_send_structured_read(req->client, request.handle, request.from, req->data, @@ -1548,6 +1553,7 @@ reply: ret < 0 ? -ret : 0, req->data, reply_data_len, &local_err); } + g_free(msg); if (ret < 0) { error_prepend(&local_err, "Failed to send reply: "); goto disconnect; diff --git a/nbd/trace-events b/nbd/trace-events index 6894f8bbb4..52150bd738 100644 --- a/nbd/trace-events +++ b/nbd/trace-events @@ -57,7 +57,7 @@ nbd_blk_aio_attached(const char *name, void *ctx) "Export %s: Attaching clients nbd_blk_aio_detach(const char *name, void *ctx) "Export %s: Detaching clients from AIO context %p\n" nbd_co_send_simple_reply(uint64_t handle, uint32_t error, const char *errname, int len) "Send simple reply: handle = %" PRIu64 ", error = %" PRIu32 " (%s), len = %d" nbd_co_send_structured_read(uint64_t handle, uint64_t offset, void *data, size_t size) "Send structured read data reply: handle = %" PRIu64 ", offset = %" PRIu64 ", data = %p, len = %zu" -nbd_co_send_structured_error(uint64_t handle, int err, const char *errname) "Send structured error reply: handle = %" PRIu64 ", error = %d (%s)" +nbd_co_send_structured_error(uint64_t handle, int err, const char *errname, const char *msg) "Send structured error reply: handle = %" PRIu64 ", error = %d (%s), msg = '%s'" nbd_co_receive_request_decode_type(uint64_t handle, uint16_t type, const char *name) "Decoding type: handle = %" PRIu64 ", type = %" PRIu16 " (%s)" nbd_co_receive_request_payload_received(uint64_t handle, uint32_t len) "Payload received: handle = %" PRIu64 ", len = %" PRIu32 nbd_co_receive_request_cmd_write(uint32_t len) "Reading %" PRIu32 " byte(s)"