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-rw-r--r--qga/commands-win32.c27
1 files changed, 27 insertions, 0 deletions
diff --git a/qga/commands-win32.c b/qga/commands-win32.c
index 97f19d5..a5306e7 100644
--- a/qga/commands-win32.c
+++ b/qga/commands-win32.c
@@ -128,6 +128,28 @@ static GuestFileHandle *guest_file_handle_find(int64_t id, Error **errp)
return NULL;
}
+static void handle_set_nonblocking(HANDLE fh)
+{
+ DWORD file_type, pipe_state;
+ file_type = GetFileType(fh);
+ if (file_type != FILE_TYPE_PIPE) {
+ return;
+ }
+ /* If file_type == FILE_TYPE_PIPE, according to MSDN
+ * the specified file is socket or named pipe */
+ if (!GetNamedPipeHandleState(fh, &pipe_state, NULL,
+ NULL, NULL, NULL, 0)) {
+ return;
+ }
+ /* The fd is named pipe fd */
+ if (pipe_state & PIPE_NOWAIT) {
+ return;
+ }
+
+ pipe_state |= PIPE_NOWAIT;
+ SetNamedPipeHandleState(fh, &pipe_state, NULL, NULL);
+}
+
int64_t qmp_guest_file_open(const char *path, bool has_mode,
const char *mode, Error **errp)
{
@@ -158,6 +180,11 @@ int64_t qmp_guest_file_open(const char *path, bool has_mode,
return -1;
}
+ /* set fd non-blocking to avoid common use cases (like reading from a
+ * named pipe) from hanging the agent
+ */
+ handle_set_nonblocking(fh);
+
fd = guest_file_handle_add(fh, errp);
if (fd < 0) {
CloseHandle(fh);