oysteikt/mpd
0
0
Fork 0
Code Issues Pull Requests Releases Activity

lib/nfs/FileReader: postpone the nfs_close_async() call

Browse Source 
If an async opertion is in progress, nfs_close_async() will make
libnfs crash because the RPC callback will dereference an object that
was freed by nfs_close_async().
This commit is contained in:
Max Kellermann
2014-09-26 13:29:44 +02:00
parent edd003b62a
commit 0661fd6f7c
4 changed files with 92 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

33
src/lib/nfs/Connection.hxx
View File

@@ -26,8 +26,11 @@
#include "event/DeferredMonitor.hxx"
#include "util/Error.hxx"
#include <boost/intrusive/list.hpp>
#include <string>
#include <list>
#include <forward_list>
struct nfs_context;
class NfsCallback;
@@ -47,13 +50,19 @@ class NfsConnection : SocketMonitor, DeferredMonitor {
*/
const bool open;
/**
* The file handle scheduled to be closed as soon as
* the operation finishes.
*/
struct nfsfh *close_fh;
public:
explicit CancellableCallback(NfsCallback &_callback,
NfsConnection &_connection,
bool _open)
:CancellablePointer<NfsCallback>(_callback),
connection(_connection),
open(_open) {}
open(_open), close_fh(nullptr) {}
bool Open(nfs_context *context, const char *path, int flags,
Error &error);
@@ -63,6 +72,12 @@ class NfsConnection : SocketMonitor, DeferredMonitor {
uint64_t offset, size_t size,
Error &error);
/**
* Cancel the operation and schedule a call to
* nfs_close_async() with the given file handle.
*/
void CancelAndScheduleClose(struct nfsfh *fh);
private:
static void Callback(int err, struct nfs_context *nfs,
void *data, void *private_data);
@@ -79,6 +94,15 @@ class NfsConnection : SocketMonitor, DeferredMonitor {
typedef CancellableList<NfsCallback, CancellableCallback> CallbackList;
CallbackList callbacks;
/**
* A list of NFS file handles (struct nfsfh *) which shall be
* closed as soon as nfs_service() returns. If we close the
* file handle while in nfs_service(), libnfs may crash, and
* deferring this call to after nfs_service() avoids this
* problem.
*/
std::forward_list<struct nfsfh *> deferred_close;
Error postponed_mount_error;
/**
@@ -135,6 +159,7 @@ public:
void Cancel(NfsCallback &callback);
void Close(struct nfsfh *fh);
void CancelAndClose(struct nfsfh *fh, NfsCallback &callback);
protected:
virtual void OnNfsConnectionError(Error &&error) = 0;
@@ -145,6 +170,12 @@ private:
}
void DestroyContext();
/**
* Invoke nfs_close_async() after nfs_service() returns.
*/
void DeferClose(struct nfsfh *fh);
bool MountInternal(Error &error);
void BroadcastMountSuccess();
void BroadcastMountError(Error &&error);