# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1625867569 -7200
# Node ID 3bfe811802d29b967852aa0c5a1fca5baae19218
# Parent  7374a07a6bf8db21c79b3226c41d8c9b2476aca5
Support multiple notifiers for each pipe endpoint.

diff -r 7374a07a6bf8 -r 3bfe811802d2 libfsclient/lib/src/notifier.cc
--- a/libfsclient/lib/src/notifier.cc	Fri Jul 09 00:15:29 2021 +0200
+++ b/libfsclient/lib/src/notifier.cc	Fri Jul 09 23:52:49 2021 +0200
@@ -85,11 +85,15 @@
   if (l4_is_invalid_cap(file->notifier))
     return -L4_EINVAL;
 
-  ipc_cap_free_um(file->notifier);
-
   client_Notification notify(file->ref);
 
-  return notify.unsubscribe();
+  long err = notify.unsubscribe(file->notifier);
+
+  if (err)
+    return err;
+
+  ipc_cap_free_um(file->notifier);
+  return L4_EOK;
 }
 
 /* Handle a notification event for a file. Ideally, this would be invoked by the
diff -r 7374a07a6bf8 -r 3bfe811802d2 libfsserver/include/fsserver/pipe_pager.h
--- a/libfsserver/include/fsserver/pipe_pager.h	Fri Jul 09 00:15:29 2021 +0200
+++ b/libfsserver/include/fsserver/pipe_pager.h	Fri Jul 09 23:52:49 2021 +0200
@@ -78,7 +78,7 @@
 
     virtual long subscribe(l4_cap_idx_t notifier, notify_flags_t flags);
 
-    virtual long unsubscribe();
+    virtual long unsubscribe(l4_cap_idx_t notifier);
 };
 
 // vim: tabstop=4 expandtab shiftwidth=4
diff -r 7374a07a6bf8 -r 3bfe811802d2 libfsserver/include/fsserver/pipe_paging.h
--- a/libfsserver/include/fsserver/pipe_paging.h	Fri Jul 09 00:15:29 2021 +0200
+++ b/libfsserver/include/fsserver/pipe_paging.h	Fri Jul 09 23:52:49 2021 +0200
@@ -21,6 +21,8 @@
 
 #pragma once
 
+#include <set>
+
 #include <fsserver/page_mapper.h>
 #include <fsserver/pages.h>
 #include <fsserver/pipe_accessor.h>
@@ -56,7 +58,7 @@
 
     /* Notification endpoints. */
 
-    l4_cap_idx_t _notifiers[2];
+    std::set<l4_cap_idx_t> _notifiers[2];
     notify_flags_t _flags[2], _deferred[2];
 
     /* Common functionality. */
@@ -77,7 +79,7 @@
 
     virtual void subscribe(bool writing, l4_cap_idx_t notifier, notify_flags_t flags);
 
-    virtual void unsubscribe(bool writing);
+    virtual void unsubscribe(bool writing, l4_cap_idx_t notifier);
 
     /* Region management. */
 
diff -r 7374a07a6bf8 -r 3bfe811802d2 libfsserver/lib/pipes/pipe_pager.cc
--- a/libfsserver/lib/pipes/pipe_pager.cc	Fri Jul 09 00:15:29 2021 +0200
+++ b/libfsserver/lib/pipes/pipe_pager.cc	Fri Jul 09 23:52:49 2021 +0200
@@ -174,9 +174,9 @@
     return L4_EOK;
 }
 
-long PipePager::unsubscribe()
+long PipePager::unsubscribe(l4_cap_idx_t notifier)
 {
-    _paging->unsubscribe(_writing);
+    _paging->unsubscribe(_writing, notifier);
     return L4_EOK;
 }
 
diff -r 7374a07a6bf8 -r 3bfe811802d2 libfsserver/lib/pipes/pipe_paging.cc
--- a/libfsserver/lib/pipes/pipe_paging.cc	Fri Jul 09 00:15:29 2021 +0200
+++ b/libfsserver/lib/pipes/pipe_paging.cc	Fri Jul 09 23:52:49 2021 +0200
@@ -47,7 +47,6 @@
 
     for (unsigned int i = 0; i < 2; i++)
     {
-        _notifiers[i] = L4_INVALID_CAP;
         _flags[i] = 0;
         _deferred[i] = 0;
     }
@@ -59,10 +58,7 @@
 {
     int i = writing ? 1 : 0;
 
-    if (l4_is_valid_cap(_notifiers[i]))
-        unsubscribe(writing);
-
-    _notifiers[i] = notifier;
+    _notifiers[i].insert(notifier);
     _flags[i] = flags;
 
     /* Send deferred conditions on behalf of the other endpoint held before
@@ -77,16 +73,17 @@
 
 /* Unsubscribe from an endpoint's notifications. */
 
-void PipePaging::unsubscribe(bool writing)
+void PipePaging::unsubscribe(bool writing, l4_cap_idx_t notifier)
 {
     int i = writing ? 1 : 0;
+    std::set<l4_cap_idx_t>::iterator it = _notifiers[i].find(notifier);
 
-    if (l4_is_valid_cap(_notifiers[i]))
+    if (it != _notifiers[i].end())
     {
-        ipc_cap_free_um(_notifiers[i]);
-        _notifiers[i] = L4_INVALID_CAP;
+        _notifiers[i].erase(it);
         _flags[i] = 0;
         _deferred[i] = 0;
+        ipc_cap_free_um(notifier);
     }
 }
 
@@ -101,13 +98,18 @@
     /* Notify the other endpoint or hold any notification for potential future
        subscription. */
 
-    if (l4_is_valid_cap(_notifiers[i]))
+    if (!_notifiers[i].empty())
     {
         if (flags & _flags[i])
         {
-            client_Notifier notifier(_notifiers[i]);
+            std::set<l4_cap_idx_t>::iterator it;
 
-            notifier.notify(flags & _flags[i]);
+            for (it = _notifiers[i].begin(); it != _notifiers[i].end(); it++)
+            {
+                client_Notifier notifier(*it);
+
+                notifier.notify(flags & _flags[i]);
+            }
         }
     }
     else
@@ -156,11 +158,12 @@
 
     for (unsigned int i = 0; i < 2; i++)
     {
-        if (l4_is_valid_cap(_notifiers[i]))
-        {
-            ipc_cap_free_um(_notifiers[i]);
-            _notifiers[i] = L4_INVALID_CAP;
-        }
+        std::set<l4_cap_idx_t>::iterator it;
+
+        for (it = _notifiers[i].begin(); it != _notifiers[i].end(); it++)
+            ipc_cap_free_um(*it);
+
+        _notifiers[i].clear();
     }
 
     /* Delete the page collection and related objects. */