Commit fb687773 authored by Olga Krishtal's avatar Olga Krishtal Committed by Michael Roth
Browse files

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



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: default avatarOlga Krishtal <okrishtal@parallels.com>
Signed-off-by: default avatarDenis V. Lunev <den@openvz.org>
CC: Michael Roth <mdroth@linux.vnet.ibm.com>
CC: Stefan Weil <sw@weilnetz.de>
Signed-off-by: default avatarMichael Roth <mdroth@linux.vnet.ibm.com>
parent c87d0964

qga/commands-win32.c

+27 −0
Original line number Diff line number Diff line
@@ -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);