1 /* 2 * A pipe paging coordinator, permitting memory sharing pipe endpoints. 3 * 4 * Copyright (C) 2021 Paul Boddie <paul@boddie.org.uk> 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License as 8 * published by the Free Software Foundation; either version 2 of 9 * the License, or (at your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program; if not, write to the Free Software 18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, 19 * Boston, MA 02110-1301, USA 20 */ 21 22 #pragma once 23 24 #include <set> 25 26 #include <fsserver/page_mapper.h> 27 #include <fsserver/pages.h> 28 #include <fsserver/pipe_accessor.h> 29 30 31 32 /* Pipe paging support, maintaining the sequence of active regions or sections 33 in a pipe. */ 34 35 class PipePaging 36 { 37 protected: 38 Memory *_memory; 39 Pages *_pages; 40 PageQueue *_queue; 41 42 /* Regions acting as files with their own accessors. */ 43 44 PageMapper *_regions[2]; 45 PipeAccessor _accessors[2]; 46 47 /* The first region is initially exposed to both reader and writer. */ 48 49 int _reading = 0, _writing = 0; 50 51 /* Pipe section/region size. */ 52 53 offset_t _size; 54 55 /* Endpoint status. */ 56 57 unsigned int _endpoints = 2; 58 59 /* Notification endpoints. */ 60 61 std::set<l4_cap_idx_t> _notifiers[2]; 62 notify_flags_t _flags[2], _deferred[2]; 63 64 /* Common functionality. */ 65 66 virtual void discard_region(unsigned int i); 67 68 public: 69 explicit PipePaging(Memory *memory, offset_t size); 70 71 virtual void detach(); 72 73 virtual offset_t region_size() 74 { return _size; } 75 76 /* Notification support. */ 77 78 virtual void notify(bool writing, notify_flags_t flags); 79 80 virtual void subscribe(bool writing, l4_cap_idx_t notifier, notify_flags_t flags); 81 82 virtual void unsubscribe(bool writing, l4_cap_idx_t notifier); 83 84 /* Region management. */ 85 86 virtual PageMapper *add_region(); 87 88 virtual PageMapper *current_region(); 89 90 virtual PageMapper *next_region(); 91 92 /* Access management. */ 93 94 virtual int closed(); 95 }; 96 97 // vim: tabstop=4 expandtab shiftwidth=4