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2016-01-20io: use memset instead of { 0 } for initializing arrayDaniel P. Berrange
Some versions of GCC on OS-X complain about CMSG_SPACE not being constant size, which prevents use of { 0 } io/channel-socket.c: In function 'qio_channel_socket_writev': io/channel-socket.c:497:18: error: variable-sized object may not be initialized char control[CMSG_SPACE(sizeof(int) * SOCKET_MAX_FDS)] = { 0 }; The compiler is at fault here, but it is nicer to avoid tickling this compiler bug by using memset instead. Reviewed-By: John Arbuckle <programmingkidx@gmail.com> Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2016-01-20io: some fixes to handling of /dev/null when running commandsDaniel P. Berrange
The /dev/null file handle was leaked in a couple of places. There is also the possibility that both readfd and writefd point to the same /dev/null file handle, so care must be taken not to close the same file handle twice. Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2016-01-19io: increment counter when killing off subcommandDaniel P. Berrange
When killing the subcommand, it is intended to first send SIGTERM, then SIGKILL and only report an error if it still doesn't die after SIGKILL. The 'step' counter was not being incremented though, so the code never got past the SIGTERM stage. Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2016-01-19io: fix sign of errno value passed to error reportDaniel P. Berrange
When reporting the number of FDs has been exceeded, pass EINVAL to error_setg_errno, rather than -EINVAL. Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2015-12-23io: fix stack allocation when sending of file descriptorsDaniel P. Berrange
When sending file descriptors over a socket, we have to allocate a data buffer to hold the FDs in the scmsghdr. Unfortunately we allocated the buffer on the stack inside an if () {} block, but called sendmsg() outside the block. So the stack bytes holding the FDs were liable to be overwritten with other data. By luck this was not a problem when sending 1 FD, but if sending 2 or more then it would fail. The fix is to simply move the variables outside the nested 'if' block. To keep valgrind quiet we also zero-initialize the 'control' buffer. Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2015-12-22io: fix setting of QIO_CHANNEL_FEATURE_FD_PASS on server connectionsDaniel P. Berrange
The QIO_CHANNEL_FEATURE_FD_PASS feature flag is set in the qio_channel_socket_set_fd() method, however, this only deals with client side connections. To ensure server side connections also have the feature flag set, we must set it in qio_channel_socket_accept() too. This also highlighted a typo fix where the code updated the sockaddr struct in the wrong object instance. Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2015-12-18io: add QIOChannelBuffer classDaniel P. Berrange
Add a QIOChannel subclass that is capable of performing I/O to/from a memory buffer. This implementation does not attempt to support concurrent readers & writers. It is designed for serialized access where by a single thread at a time may write data, seek and then read data back out. Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2015-12-18io: add QIOChannelCommand classDaniel P. Berrange
Add a QIOChannel subclass that is capable of performing I/O to/from a separate process, via a pair of pipes. The command can be used for unidirectional or bi-directional I/O. Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2015-12-18io: add QIOChannelWebsock classDaniel P. Berrange
Add a QIOChannel subclass that can run the websocket protocol over the top of another QIOChannel instance. This initial implementation is only capable of acting as a websockets server. There is no support for acting as a websockets client yet. Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2015-12-18io: add QIOChannelTLS classDaniel P. Berrange
Add a QIOChannel subclass that can run the TLS protocol over the top of another QIOChannel instance. The object provides a simplified API to perform the handshake when starting the TLS session. The layering of TLS over the underlying channel does not have to be setup immediately. It is possible to take an existing QIOChannel that has done some handshake and then swap in the QIOChannelTLS layer. This allows for use with protocols which start TLS right away, and those which start plain text and then negotiate TLS. Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2015-12-18io: add QIOChannelFile classDaniel P. Berrange
Add a QIOChannel subclass that is capable of operating on things that are files, such as plain files, pipes, character/block devices, but notably not sockets. Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2015-12-18io: add QIOChannelSocket classDaniel P. Berrange
Implement a QIOChannel subclass that supports sockets I/O. The implementation is able to manage a single socket file descriptor, whether a TCP/UNIX listener, TCP/UNIX connection, or a UDP datagram. It provides APIs which can listen and connect either asynchronously or synchronously. Since there is no asynchronous DNS lookup API available, it uses the QIOTask helper for spawning a background thread to ensure non-blocking operation. Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2015-12-18io: add QIOTask class for async operationsDaniel P. Berrange
A number of I/O operations need to be performed asynchronously to avoid blocking the main loop. The caller of such APIs need to provide a callback to be invoked on completion/error and need access to the error, if any. The small QIOTask provides a simple framework for dealing with such probes. The API docs inline provide an outline of how this is to be used. Some functions don't have the ability to run asynchronously (eg getaddrinfo always blocks), so to facilitate their use, the task class provides a mechanism to run a blocking function in a thread, while triggering the completion callback in the main event loop thread. This easily allows any synchronous function to be made asynchronous, albeit at the cost of spawning a thread. In this series, the QIOTask class will be used for things like the TLS handshake, the websockets handshake and TCP connect() progress. The concept of QIOTask is inspired by the GAsyncResult interface / GTask class in the GIO libraries. The min version requirements on glib don't allow those to be used from QEMU, so QIOTask provides a facsimilie which can be easily switched to GTask in the future if the min version is increased. Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2015-12-18io: add helper module for creating watches on FDsDaniel P. Berrange
A number of the channel implementations will require the ability to create watches on file descriptors / sockets. To avoid duplicating this code in each channel, provide a helper API for dealing with file descriptor watches. There are two watch implementations provided. The first is useful for bi-directional file descriptors such as sockets, regular files, character devices, etc. The second works with a pair of unidirectional file descriptors such as pipes. Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2015-12-18io: add abstract QIOChannel classesDaniel P. Berrange
Start the new generic I/O channel framework by defining a QIOChannel abstract base class. This is designed to feel similar to GLib's GIOChannel, but with the addition of support for using iovecs, qemu error reporting, file descriptor passing, coroutine integration and use of the QOM framework for easier sub-classing. The intention is that anywhere in QEMU that almost anywhere that deals with sockets will use this new I/O infrastructure, so that it becomes trivial to then layer in support for TLS encryption. This will at least include the VNC server, char device backend and migration code. Signed-off-by: Daniel P. Berrange <berrange@redhat.com>