[libvirt] [PATCH 01/10] fdstream: Emit stream abort callback even if poll() doesnt.

This patch causes the fdstream driver to call the stream event callback if virStreamAbort() is issued on a stream using this driver. This prohibited to abort streams from the daemon, as the daemon remote handler installs a callback to watch for stream errors as the only mean of detecting changes in the stream. --- src/fdstream.c | 52 +++++++++++++++++++++++++++++++++++++++++++++++----- 1 files changed, 47 insertions(+), 5 deletions(-) diff --git a/src/fdstream.c b/src/fdstream.c index b60162c..8fb5e78 100644 --- a/src/fdstream.c +++ b/src/fdstream.c @@ -55,6 +55,7 @@ struct virFDStreamData { unsigned long long length; int watch; + int events; /* events the stream callback is subscribed for */ bool cbRemoved; bool dispatching; bool closed; @@ -62,6 +63,9 @@ struct virFDStreamData { void *opaque; virFreeCallback ff; + /* don't call the abort callback more than once */ + bool abortCallbackCalled; + virMutex lock; }; @@ -92,6 +96,7 @@ static int virFDStreamRemoveCallback(virStreamPtr stream) fdst->watch = 0; fdst->ff = NULL; fdst->cb = NULL; + fdst->events = 0; fdst->opaque = NULL; ret = 0; @@ -120,6 +125,7 @@ static int virFDStreamUpdateCallback(virStreamPtr stream, int events) } virEventUpdateHandle(fdst->watch, events); + fdst->events = events; ret = 0; @@ -214,6 +220,8 @@ virFDStreamAddCallback(virStreamPtr st, fdst->cb = cb; fdst->opaque = opaque; fdst->ff = ff; + fdst->events = events; + fdst->abortCallbackCalled = false; virStreamRef(st); ret = 0; @@ -223,18 +231,40 @@ cleanup: return ret; } - static int -virFDStreamClose(virStreamPtr st) +virFDStreamCloseInt(virStreamPtr st, bool streamAbort) { - struct virFDStreamData *fdst = st->privateData; + struct virFDStreamData *fdst; int ret; VIR_DEBUG("st=%p", st); - if (!fdst) + if (!st || !(fdst = st->privateData)) return 0; + /* aborting the stream, ensure the callback is called if it's + * registered for stream error event */ + if (streamAbort && + fdst->cb && + (fdst->events & VIR_STREAM_EVENT_ERROR)) { + /* don't enter this function accidentaly from the callback again */ + virMutexLock(&fdst->lock); + if (fdst->abortCallbackCalled) { + virMutexUnlock(&fdst->lock); + return 0; + } + + fdst->abortCallbackCalled = true; + virMutexUnlock(&fdst->lock); + + /* call failure callback, poll does report nothing on closed fd */ + (fdst->cb)(st, VIR_STREAM_EVENT_ERROR, fdst->opaque); + + /* re-check the pointer, someone could tamper with it in the callback */ + if (!(fdst = st->privateData)) + return 0; + } + virMutexLock(&fdst->lock); ret = VIR_CLOSE(fdst->fd); @@ -282,6 +312,18 @@ virFDStreamClose(virStreamPtr st) return ret; } +static int +virFDStreamClose(virStreamPtr st) +{ + return virFDStreamCloseInt(st, false); +} + +static int +virFDStreamAbort(virStreamPtr st) +{ + return virFDStreamCloseInt(st, true); +} + static int virFDStreamWrite(virStreamPtr st, const char *bytes, size_t nbytes) { struct virFDStreamData *fdst = st->privateData; @@ -388,7 +430,7 @@ static virStreamDriver virFDStreamDrv = { .streamSend = virFDStreamWrite, .streamRecv = virFDStreamRead, .streamFinish = virFDStreamClose, - .streamAbort = virFDStreamClose, + .streamAbort = virFDStreamAbort, .streamAddCallback = virFDStreamAddCallback, .streamUpdateCallback = virFDStreamUpdateCallback, .streamRemoveCallback = virFDStreamRemoveCallback -- 1.7.3.4