From 75ac495dc9d6aa3d6240bfab1adbdc0d0f8bc403 Mon Sep 17 00:00:00 2001 From: Anthony PERARD Date: Fri, 27 Jul 2018 15:05:47 +0100 Subject: [PATCH] libxl_qmp: Move the buffer realloc to the same scope level as read In qmp_next(), the inner loop should only try to parse messages from QMP, if there is more than one. The handling of the receive buffer ('incomplete'), should be done at the same scope level as read(). It doesn't need to be handle more that once after a read. Before this patch, when on message what handled, the inner loop would restart by adding the 'buffer' into 'incomplete' (after reallocation). Since 'rd' was not reset, the buffer would be strcat a second time. After that, the stream from the QMP server would have syntax error, and the parsor would throw errors. This is unlikely to happen as the receive buffer is very large. And receiving two messages in a row is unlikely. In the current case, this could be an event and a response to a command. Signed-off-by: Anthony PERARD Acked-by: Ian Jackson --- tools/libxl/libxl_qmp.c | 31 ++++++++++++++++--------------- 1 file changed, 16 insertions(+), 15 deletions(-) diff --git a/tools/libxl/libxl_qmp.c b/tools/libxl/libxl_qmp.c index 27227802e4..5b608f47e5 100644 --- a/tools/libxl/libxl_qmp.c +++ b/tools/libxl/libxl_qmp.c @@ -530,23 +530,24 @@ static int qmp_next(libxl__gc *gc, libxl__qmp_handler *qmp) DEBUG_REPORT_RECEIVED(qmp->domid, qmp->buffer, (int)rd); + if (incomplete) { + size_t current_pos = s - incomplete; + incomplete = libxl__realloc(gc, incomplete, + incomplete_size + rd + 1); + strncat(incomplete + incomplete_size, qmp->buffer, rd); + s = incomplete + current_pos; + incomplete_size += rd; + s_end = incomplete + incomplete_size; + } else { + incomplete = libxl__strndup(gc, qmp->buffer, rd); + incomplete_size = rd; + s = incomplete; + s_end = s + rd; + rd = 0; + } + do { char *end = NULL; - if (incomplete) { - size_t current_pos = s - incomplete; - incomplete = libxl__realloc(gc, incomplete, - incomplete_size + rd + 1); - strncat(incomplete + incomplete_size, qmp->buffer, rd); - s = incomplete + current_pos; - incomplete_size += rd; - s_end = incomplete + incomplete_size; - } else { - incomplete = libxl__strndup(gc, qmp->buffer, rd); - incomplete_size = rd; - s = incomplete; - s_end = s + rd; - rd = 0; - } end = strstr(s, "\r\n"); if (end) { -- 2.30.2