Quoting Michael Roth (2015-10-27 14:11:12)
> Quoting Denis V. Lunev (2015-10-27 12:48:43)
> > From: Olga Krishtal <okrish...@parallels.com>
> >
> > 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 analog of qemu_set_non/block 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.
>
> If this is specific to HANDLEs, why do we need to cast back and forth
> between int64_t and HANDLE? I haven't build tested, but it seems like
> this would break for 32-bit mingw builds.
>
> I would define these as qemu_set_*_by_handle(HANDLE fh, ...) instead
> and make them win32 only. If someone wants to introduce a FILE*
> variant for posix they can introduce it as
> qemu_set_*_by_handle(FILE *fh, ...) rather than us needing to
> abstract away the handle type.
Actually that would be silly since win32 has FILE as well. So I think
this interface will only ever make sense for HANDLE so let's be
explicit about it.
>
> >
> > Signed-off-by: Olga Krishtal <okrish...@parallels.com>
> > Signed-off-by: Denis V. Lunev <d...@openvz.org>
> > CC: Michael Roth <mdr...@linux.vnet.ibm.com>
> > CC: Stefan Weil <s...@weilnetz.de>
> > ---
> > include/qemu/sockets.h | 2 ++
> > qga/commands-win32.c | 6 ++++++
> > util/oslib-win32.c | 41 +++++++++++++++++++++++++++++++++++++++++
> > 3 files changed, 49 insertions(+)
> >
> > diff --git a/include/qemu/sockets.h b/include/qemu/sockets.h
> > index 5a183c5..e2323f4 100644
> > --- a/include/qemu/sockets.h
> > +++ b/include/qemu/sockets.h
> > @@ -39,6 +39,8 @@ int socket_set_cork(int fd, int v);
> > int socket_set_nodelay(int fd);
> > void qemu_set_block(int fd);
> > void qemu_set_nonblock(int fd);
> > +void qemu_set_nonblock_by_handle(int64_t fh);
> > +void qemu_set_block_by_handle(int64_t fh);
> > int socket_set_fast_reuse(int fd);
> > int send_all(int fd, const void *buf, int len1);
> > int recv_all(int fd, void *buf, int len1, bool single_read);
> > diff --git a/qga/commands-win32.c b/qga/commands-win32.c
> > index 97f19d5..f959d75 100644
> > --- a/qga/commands-win32.c
> > +++ b/qga/commands-win32.c
> > @@ -34,6 +34,7 @@
> > #include "qapi/qmp/qerror.h"
> > #include "qemu/queue.h"
> > #include "qemu/host-utils.h"
> > +#include "qemu/sockets.h"
> >
> > #ifndef SHTDN_REASON_FLAG_PLANNED
> > #define SHTDN_REASON_FLAG_PLANNED 0x80000000
> > @@ -158,6 +159,11 @@ 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
> > + */
> > + qemu_set_nonblock_by_handle((int64_t)fh);
> > +
> > fd = guest_file_handle_add(fh, errp);
> > if (fd < 0) {
> > CloseHandle(fh);
> > diff --git a/util/oslib-win32.c b/util/oslib-win32.c
> > index 09f9e98..4a9fd8e 100644
> > --- a/util/oslib-win32.c
> > +++ b/util/oslib-win32.c
> > @@ -121,6 +121,37 @@ struct tm *localtime_r(const time_t *timep, struct tm
> > *result)
> > }
> > #endif /* CONFIG_LOCALTIME_R */
> >
> > +static void qemu_set_handle_nonblocking(int64_t fh, bool nonblocking)
> > +{
> > + DWORD file_type, pipe_state;
> > + HANDLE handle = (HANDLE)fh;
> > + file_type = GetFileType(handle);
> > + 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(handle, &pipe_state, NULL,
> > + NULL, NULL, NULL, 0)) {
> > + return;
> > + }
> > + /* The fd is named pipe fd */
> > + if (!nonblocking == !(pipe_state & PIPE_NOWAIT)) {
> > + /* In this case we do not need perform any operation, because
> > + * nonblocking = true and PIPE_NOWAIT is already set or
> > + * nonblocking = false and PIPE_NOWAIT is not set */
> > + return;
> > + }
> > +
> > + if (nonblocking) {
> > + pipe_state |= PIPE_NOWAIT;
> > + } else {
> > + pipe_state &= ~PIPE_NOWAIT;
> > + }
> > +
> > + SetNamedPipeHandleState(handle, &pipe_state, NULL, NULL);
> > +}
> > +
> > void qemu_set_block(int fd)
> > {
> > unsigned long opt = 0;
> > @@ -135,6 +166,16 @@ void qemu_set_nonblock(int fd)
> > qemu_fd_register(fd);
> > }
> >
> > +void qemu_set_block_by_handle(int64_t fh)
> > +{
> > + qemu_set_handle_nonblocking(fh, false);
> > +}
> > +
> > +void qemu_set_nonblock_by_handle(int64_t fh)
> > +{
> > + qemu_set_handle_nonblocking(fh, true);
> > +}
> > +
> > int socket_set_fast_reuse(int fd)
> > {
> > /* Enabling the reuse of an endpoint that was used by a socket still in
> > --
> > 2.1.4
> >
