diff options
author | Eric Blake <eblake@redhat.com> | 2016-10-14 13:33:09 -0500 |
---|---|---|
committer | Paolo Bonzini <pbonzini@redhat.com> | 2016-11-02 09:28:55 +0100 |
commit | 3668328303429f3bc93ab3365c66331600b06a2d (patch) | |
tree | c8f412dde07649081e32aab9878cf016e5b94831 /nbd | |
parent | 526e5c6559928ed98332dd27f026e8cbc95f466a (diff) | |
download | qemu-3668328303429f3bc93ab3365c66331600b06a2d.zip qemu-3668328303429f3bc93ab3365c66331600b06a2d.tar.gz qemu-3668328303429f3bc93ab3365c66331600b06a2d.tar.bz2 |
nbd: Send message along with server NBD_REP_ERR errors
The NBD Protocol allows us to send human-readable messages
along with any NBD_REP_ERR error during option negotiation;
make use of this fact for clients that know what to do with
our message.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1476469998-28592-8-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'nbd')
-rw-r--r-- | nbd/server.c | 78 |
1 files changed, 59 insertions, 19 deletions
diff --git a/nbd/server.c b/nbd/server.c index 0f0c68c..fa01e49 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -236,6 +236,38 @@ static int nbd_negotiate_send_rep(QIOChannel *ioc, uint32_t type, uint32_t opt) return nbd_negotiate_send_rep_len(ioc, type, opt, 0); } +/* Send an error reply. + * Return -errno on error, 0 on success. */ +static int GCC_FMT_ATTR(4, 5) +nbd_negotiate_send_rep_err(QIOChannel *ioc, uint32_t type, + uint32_t opt, const char *fmt, ...) +{ + va_list va; + char *msg; + int ret; + size_t len; + + va_start(va, fmt); + msg = g_strdup_vprintf(fmt, va); + va_end(va); + len = strlen(msg); + assert(len < 4096); + TRACE("sending error message \"%s\"", msg); + ret = nbd_negotiate_send_rep_len(ioc, type, opt, len); + if (ret < 0) { + goto out; + } + if (nbd_negotiate_write(ioc, msg, len) != len) { + LOG("write failed (error message)"); + ret = -EIO; + } else { + ret = 0; + } +out: + g_free(msg); + return ret; +} + /* Send a single NBD_REP_SERVER reply to NBD_OPT_LIST, including payload. * Return -errno on error, 0 on success. */ static int nbd_negotiate_send_rep_list(QIOChannel *ioc, NBDExport *exp) @@ -281,8 +313,9 @@ static int nbd_negotiate_handle_list(NBDClient *client, uint32_t length) if (nbd_negotiate_drop_sync(client->ioc, length) != length) { return -EIO; } - return nbd_negotiate_send_rep(client->ioc, - NBD_REP_ERR_INVALID, NBD_OPT_LIST); + return nbd_negotiate_send_rep_err(client->ioc, + NBD_REP_ERR_INVALID, NBD_OPT_LIST, + "OPT_LIST should not have length"); } /* For each export, send a NBD_REP_SERVER reply. */ @@ -329,7 +362,8 @@ fail: return rc; } - +/* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the + * new channel for all further (now-encrypted) communication. */ static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client, uint32_t length) { @@ -343,7 +377,8 @@ static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client, if (nbd_negotiate_drop_sync(ioc, length) != length) { return NULL; } - nbd_negotiate_send_rep(ioc, NBD_REP_ERR_INVALID, NBD_OPT_STARTTLS); + nbd_negotiate_send_rep_err(ioc, NBD_REP_ERR_INVALID, NBD_OPT_STARTTLS, + "OPT_STARTTLS should not have length"); return NULL; } @@ -474,13 +509,15 @@ static int nbd_negotiate_options(NBDClient *client) return -EINVAL; default: - TRACE("Option 0x%" PRIx32 " not permitted before TLS", - clientflags); if (nbd_negotiate_drop_sync(client->ioc, length) != length) { return -EIO; } - ret = nbd_negotiate_send_rep(client->ioc, NBD_REP_ERR_TLS_REQD, - clientflags); + ret = nbd_negotiate_send_rep_err(client->ioc, + NBD_REP_ERR_TLS_REQD, + clientflags, + "Option 0x%" PRIx32 + "not permitted before TLS", + clientflags); if (ret < 0) { return ret; } @@ -506,27 +543,30 @@ static int nbd_negotiate_options(NBDClient *client) return -EIO; } if (client->tlscreds) { - TRACE("TLS already enabled"); - ret = nbd_negotiate_send_rep(client->ioc, - NBD_REP_ERR_INVALID, - clientflags); + ret = nbd_negotiate_send_rep_err(client->ioc, + NBD_REP_ERR_INVALID, + clientflags, + "TLS already enabled"); } else { - TRACE("TLS not configured"); - ret = nbd_negotiate_send_rep(client->ioc, - NBD_REP_ERR_POLICY, - clientflags); + ret = nbd_negotiate_send_rep_err(client->ioc, + NBD_REP_ERR_POLICY, + clientflags, + "TLS not configured"); } if (ret < 0) { return ret; } break; default: - TRACE("Unsupported option 0x%" PRIx32, clientflags); if (nbd_negotiate_drop_sync(client->ioc, length) != length) { return -EIO; } - ret = nbd_negotiate_send_rep(client->ioc, NBD_REP_ERR_UNSUP, - clientflags); + ret = nbd_negotiate_send_rep_err(client->ioc, + NBD_REP_ERR_UNSUP, + clientflags, + "Unsupported option 0x%" + PRIx32, + clientflags); if (ret < 0) { return ret; } |