# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1620340262 -7200
# Node ID d3ed5dc0b98dcf5e123a55a20a22b9fc2496cef5
# Parent  13859678adc286f0dc46ed04c2c66cad415cb318
Produce different error codes depending on whether endpoints have been closed.

diff -r 13859678adc2 -r d3ed5dc0b98d libfsserver/include/fsserver/pipe_pager.h
--- a/libfsserver/include/fsserver/pipe_pager.h	Wed May 05 00:09:11 2021 +0200
+++ b/libfsserver/include/fsserver/pipe_pager.h	Fri May 07 00:31:02 2021 +0200
@@ -42,6 +42,8 @@
 
     virtual long next_region_for_writer(offset_t *populated_size, offset_t *size);
 
+    virtual long pipe_error();
+
 public:
     explicit PipePager(PipePaging *paging, bool writer);
 
diff -r 13859678adc2 -r d3ed5dc0b98d libfsserver/include/fsserver/pipe_paging.h
--- a/libfsserver/include/fsserver/pipe_paging.h	Wed May 05 00:09:11 2021 +0200
+++ b/libfsserver/include/fsserver/pipe_paging.h	Fri May 07 00:31:02 2021 +0200
@@ -69,6 +69,10 @@
     virtual PageMapper *current_region();
 
     virtual PageMapper *next_region();
+
+    /* Access management. */
+
+    virtual int closed();
 };
 
 // vim: tabstop=4 expandtab shiftwidth=4
diff -r 13859678adc2 -r d3ed5dc0b98d libfsserver/lib/pipes/pipe_pager.cc
--- a/libfsserver/lib/pipes/pipe_pager.cc	Wed May 05 00:09:11 2021 +0200
+++ b/libfsserver/lib/pipes/pipe_pager.cc	Fri May 07 00:31:02 2021 +0200
@@ -77,7 +77,7 @@
         return L4_EOK;
     }
     else
-        return -L4_EIO;
+        return pipe_error();
 }
 
 /* Obtain the next region and its details. */
@@ -97,7 +97,7 @@
     PageMapper *mapper = _paging->next_region();
 
     if (mapper == NULL)
-        return -L4_EIO;
+        return pipe_error();
 
     _mapper = mapper;
 
@@ -116,11 +116,19 @@
     PageMapper *mapper = _paging->add_region();
 
     if (mapper == NULL)
-        return -L4_EIO;
+        return pipe_error();
 
     _mapper = mapper;
 
     return current_region(populated_size, size);
 }
 
+long PipePager::pipe_error()
+{
+    if (_paging->closed())
+        return -L4_EIO;
+    else
+        return -L4_EBUSY;
+}
+
 // vim: tabstop=4 expandtab shiftwidth=4
diff -r 13859678adc2 -r d3ed5dc0b98d libfsserver/lib/pipes/pipe_paging.cc
--- a/libfsserver/lib/pipes/pipe_paging.cc	Wed May 05 00:09:11 2021 +0200
+++ b/libfsserver/lib/pipes/pipe_paging.cc	Fri May 07 00:31:02 2021 +0200
@@ -36,10 +36,19 @@
     _queue = new PageQueuePartitioned();
     _pages = new Pages(_memory, _queue);
 
+    /* Reset the mappers associated with the regions. */
+
     for (unsigned int i = 0; i < 2; i++)
         _regions[i] = NULL;
 }
 
+/* Return whether one or more endpoints have detached. */
+
+int PipePaging::closed()
+{
+    return _endpoints < 2;
+}
+
 /* Detach one endpoint. */
 
 void PipePaging::detach()
@@ -131,9 +140,12 @@
         delete mapper;
     }
 
-    /* Return the next region. */
+    /* Select the next region. */
 
     _reading = 1 - _reading;
+
+    /* Return the next region's mapper. */
+
     return _regions[_reading];
 }