mirror of
https://github.com/gnif/LookingGlass.git
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95 lines
2.2 KiB
C
95 lines
2.2 KiB
C
/*
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KVMGFX Client - A KVM Client for VGA Passthrough
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Copyright (C) 2017-2019 Geoffrey McRae <geoff@hostfission.com>
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https://looking-glass.hostfission.com
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This program is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free Software
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Foundation; either version 2 of the License, or (at your option) any later
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version.
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This program is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
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PARTICULAR PURPOSE. See the GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along with
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this program; if not, write to the Free Software Foundation, Inc., 59 Temple
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Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include "common/framebuffer.h"
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#include "common/debug.h"
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#include <string.h>
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#define FB_CHUNK_SIZE 1024
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struct stFrameBuffer
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{
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uint64_t wp;
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uint8_t data[0];
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};
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bool framebuffer_read(const FrameBuffer frame, void * dst, size_t size)
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{
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uint8_t *d = (uint8_t*)dst;
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uint64_t rp = 0;
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while(rp < size)
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{
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/* spinlock */
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while(rp == frame->wp) { }
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/* copy what we can */
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uint64_t avail = frame->wp - rp;
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avail = avail > size ? size : avail;
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memcpy(d, frame->data + rp, avail);
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rp += avail;
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d += avail;
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size -= avail;
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}
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return true;
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}
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bool framebuffer_read_fn(const FrameBuffer frame, FrameBufferReadFn fn, size_t size, void * opaque)
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{
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uint64_t rp = 0;
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while(rp < size)
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{
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/* spinlock */
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while(rp == frame->wp) { }
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/* copy what we can */
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uint64_t avail = frame->wp - rp;
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avail = avail > size ? size : avail;
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if (!fn(opaque, frame->data + rp, avail))
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return false;
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rp += avail;
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size -= avail;
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}
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return true;
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}
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/**
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* Prepare the framebuffer for writing
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*/
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void framebuffer_prepare(const FrameBuffer frame)
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{
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frame->wp = 0;
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}
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bool framebuffer_write(FrameBuffer frame, const void * src, size_t size)
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{
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/* copy in chunks */
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while(size)
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{
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size_t copy = size < FB_CHUNK_SIZE ? FB_CHUNK_SIZE : size;
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memcpy(frame->data + frame->wp, src, copy);
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__sync_fetch_and_add(&frame->wp, copy);
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size -= copy;
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}
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return true;
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} |