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Fixed a race condition that could corrupt memory: Usually, clients of this

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API will call AddDirectory() in whatever random thread, not in the AddOnMonitor
looper thread however. The looper thread will try to process pending node
monitor events every second which may happen concurrently to the thread
adding to the fPendingEntries list for initial processing of new directories.
Could have affected any of the AddOnMonitor clients, like media_server and
input_server.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@38235 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
Stephan Aßmus 2010-08-18 13:55:36 +00:00
parent c6077ae7ec
commit 3f918dc3fa
1 changed files with 18 additions and 12 deletions
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30
src/kits/storage/AddOnMonitorHandler.cpp
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@ -44,6 +44,14 @@ AddOnMonitorHandler::MessageReceived(BMessage* msg)
status_t
AddOnMonitorHandler::AddDirectory(const node_ref* nref)
{
// Keep the looper thread locked, since this method is likely to be called
// in a thread other than the looper thread. Otherwise we may access the
// lists concurrently with the looper thread, when node monitor notifications
// arrive while we are still adding initial entries from the directory, or
// (much more likely) if the looper thread handles a pulse message and wants
// to process pending entries while we are still adding them.
BAutolock _(Looper());
// ignore directories added twice
std::list<add_on_directory_info>::iterator iterator = fDirectories.begin();
for (; iterator != fDirectories.end() ; iterator++) {
@ -166,12 +174,11 @@ AddOnMonitorHandler::EntryRemoved(ino_t directory, dev_t device, ino_t node)
}
// if it was not found, we're done
if (diter == fDirectories.end()) {
if (diter == fDirectories.end())
return;
}
// Start at the top again, and search until the directory we found
// the old add-on in. If we find a add-on with the same name then
// the old add-on in. If we find an add-on with the same name then
// the old add-on was not enabled. So we deallocate the old
// add-on and return.
std::list<add_on_directory_info>::iterator diter2 = fDirectories.begin();
@ -190,7 +197,7 @@ AddOnMonitorHandler::EntryRemoved(ino_t directory, dev_t device, ino_t node)
AddOnDisabled(&info);
AddOnRemoved(&info);
// Continue searching for a add-on below us. If we find a add-on
// Continue searching for an add-on below us. If we find an add-on
// with the same name, we must enable it.
for (diter++ ; diter != fDirectories.end() ; diter++) {
std::list<add_on_entry_info>::iterator eiter = diter->entries.begin();
@ -222,13 +229,13 @@ AddOnMonitorHandler::EntryMoved(const char* name, ino_t fromDirectory,
make_node_ref(device, toDirectory, &toNodeRef);
std::list<add_on_directory_info>::iterator to_iter = fDirectories.begin();
for ( ; to_iter != fDirectories.end() ; to_iter++) {
if (to_iter->nref == toNodeRef) {
if (to_iter->nref == toNodeRef)
break;
}
}
if (from_iter == fDirectories.end() && to_iter == fDirectories.end()) {
// huh? whatever...
// It seems the notification was for a directory we are not
// actually watching by intention.
return;
}
@ -290,9 +297,8 @@ AddOnMonitorHandler::EntryMoved(const char* name, ino_t fromDirectory,
}
// finally, if the new name is different, destroy the addon
if (strcmp(info.name, name) != 0) {
if (strcmp(info.name, name) != 0)
AddOnRemoved(&info);
}
// done
return;
@ -480,8 +486,8 @@ AddOnMonitorHandler::_HandlePulse()
add_on_entry_info info = *iter;
node_ref dirNodeRef;
if ((directory.GetNodeRef(&dirNodeRef) != B_OK) ||
(dirNodeRef != info.dir_nref)) {
if (directory.GetNodeRef(&dirNodeRef) != B_OK
|| dirNodeRef != info.dir_nref) {
if (directory.SetTo(&info.dir_nref) != B_OK) {
// invalid directory, discard this pending entry
iter = fPendingEntries.erase(iter);
@ -520,7 +526,7 @@ AddOnMonitorHandler::_HandlePulse()
AddOnCreated(&info);
// Start at the top again, and search until the directory we put
// the new add-on in. If we find a add-on with the same name then
// the new add-on in. If we find an add-on with the same name then
// the new add-on should not be enabled.
bool enabled = true;
std::list<add_on_directory_info>::iterator diter2