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win32: avoid mixing SOCKET and file descriptor space

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Until now, a win32 SOCKET handle is often cast to an int file
descriptor, as this is what other OS use for sockets. When necessary,
QEMU eventually queries whether it's a socket with the help of
fd_is_socket(). However, there is no guarantee of conflict between the
fd and SOCKET space. Such conflict would have surprising consequences,
we shouldn't mix them.

Also, it is often forgotten that SOCKET must be closed with
closesocket(), and not close().

Instead, let's make the win32 socket wrapper functions return and take a
file descriptor, and let util/ wrappers do the fd/SOCKET conversion as
necessary. A bit of adaptation is necessary in io/ as well.

Unfortunately, we can't drop closesocket() usage, despite
_open_osfhandle() documentation claiming transfer of ownership, testing
shows bad behaviour if you forget to call closesocket().

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Message-Id: <20230221124802.4103554-15-marcandre.lureau@redhat.com>
This commit is contained in:
Marc-André Lureau 2023-02-21 16:47:59 +04:00
parent fd3c333315
commit abe34282b0
4 changed files with 226 additions and 70 deletions
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9
util/aio-win32.c
View file

@ -73,15 +73,18 @@ void aio_set_fd_handler(AioContext *ctx,
{
AioHandler *old_node;
AioHandler *node = NULL;
SOCKET s;
if (!fd_is_socket(fd)) {
error_report("fd=%d is not a socket, AIO implementation is missing", fd);
return;
}
s = _get_osfhandle(fd);
qemu_lockcnt_lock(&ctx->list_lock);
QLIST_FOREACH(old_node, &ctx->aio_handlers, node) {
if (old_node->pfd.fd == fd && !old_node->deleted) {
if (old_node->pfd.fd == s && !old_node->deleted) {
break;
}
}
@ -92,7 +95,7 @@ void aio_set_fd_handler(AioContext *ctx,
/* Alloc and insert if it's not already there */
node = g_new0(AioHandler, 1);
node->pfd.fd = fd;
node->pfd.fd = s;
node->pfd.events = 0;
if (node->io_read) {
@ -120,7 +123,7 @@ void aio_set_fd_handler(AioContext *ctx,
QLIST_INSERT_HEAD_RCU(&ctx->aio_handlers, node, node);
event = event_notifier_get_handle(&ctx->notifier);
qemu_socket_select(node->pfd.fd, event, bitmask, NULL);
qemu_socket_select(fd, event, bitmask, NULL);
}
if (old_node) {
aio_remove_fd_handler(ctx, old_node);