[Qemu-devel] Bug in net/socket.c: info_str is overwritten

[Miguel Di Ciurcio Filho <miguel.filho@gmail.com>]

Hi there,

I'm working on the conversion of the 'info network' command do QMP,
and I think I've found some problems.

Running qemu like this: qemu -net socket,listen=:3333

In net/socket.c, the function net_socket_listen_init() [1] is called
and a listening socket is created. There is nothing registering this,
so when using 'info network' as is, no information about this
listening socket is shown.

When a connection is accepted, the handler net_socket_accept() calls
net_socket_fd_init(). If the socket is
UDP/multicast net_socket_fd_init() calls net_socket_fd_init_dgram, if
the socket is TCP it calls net_socket_fd_init_dgram_stream. [2]

In both cases the info_str string is written inside
net_socket_fd_init_(stream|dgram) [3], and after that, it is
overwritten on a subsequent
snprintf() in net_socket_accept() [4].

net_socket_fd_init_(stream|dgram) always puts into the info_str the fd
number, and this information is overwritten latter. So, is the fd
number
relevant to be transmitted over QMP? Right now this information is
being lost, IMHO.

Same thing happens when qemu is run as a client:
net_socket_connect_init() calls net_socket_fd_init_(dgram|stream) and
latter overwrites info_str.

[1] http://git.qemu.org/qemu.git/tree/net/socket.c#n375
[2] http://git.qemu.org/qemu.git/tree/net/socket.c#n336
[3] http://git.qemu.org/qemu.git/tree/net/socket.c#n310
[4] http://git.qemu.org/qemu.git/tree/net/socket.c#n369