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qga: set file descriptor in qmp_guest_file_open non-blocking on Win32

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Set fd non-blocking to avoid common use cases (like reading from a
named pipe) from hanging the agent. This was missed in the original
code.

The patch introduces qemu_set_handle_nonoblocking, the local analog
of qemu_set_nonblock for HANDLES.
The usage of handles in qemu_set_non/block is impossible, because for
win32 there is a difference between file discriptors and file handles,
and all file ops are made via Win32 api.

Signed-off-by: Olga Krishtal <okrishtal@parallels.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Michael Roth <mdroth@linux.vnet.ibm.com>
CC: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
This commit is contained in:
Olga Krishtal 2015-10-28 18:13:57 +03:00 committed by Michael Roth
parent c87d0964ef
commit fb68777312
1 changed files with 27 additions and 0 deletions
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27
qga/commands-win32.c
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@ -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);