File indexing completed on 2024-05-19 05:31:37

 /*
     SPDX-FileCopyrightText: 2023 Vlad Zahorodnii <vlad.zahorodnii@kde.org>
 
     SPDX-License-Identifier: GPL-2.0-or-later
 */
 
 #include "core/shmgraphicsbufferallocator.h"
 
 #include "config-kwin.h"
 
 #include "core/graphicsbuffer.h"
 #include "utils/memorymap.h"
 
 #include <drm_fourcc.h>
 #include <fcntl.h>
 #include <sys/mman.h>
 #include <unistd.h>
 
 namespace KWin
 {
 
 class ShmGraphicsBuffer : public GraphicsBuffer
 {
     Q_OBJECT
 
 public:
     ShmGraphicsBuffer(ShmAttributes &&attributes, MemoryMap &&memoryMap);
 
     Map map(MapFlags flags) override;
     void unmap() override;
 
     QSize size() const override;
     bool hasAlphaChannel() const override;
     const ShmAttributes *shmAttributes() const override;
 
 private:
     ShmAttributes m_attributes;
     MemoryMap m_memoryMap;
     bool m_hasAlphaChannel;
 };
 
 ShmGraphicsBuffer::ShmGraphicsBuffer(ShmAttributes &&attributes, MemoryMap &&memoryMap)
     : m_attributes(std::move(attributes))
     , m_memoryMap(std::move(memoryMap))
     , m_hasAlphaChannel(alphaChannelFromDrmFormat(attributes.format))
 {
 }
 
 GraphicsBuffer::Map ShmGraphicsBuffer::map(MapFlags flags)
 {
     if (m_memoryMap.isValid()) {
         return Map{
             .data = m_memoryMap.data(),
             .stride = uint32_t(m_attributes.stride),
         };
     } else {
         return Map{};
     }
 }
 
 void ShmGraphicsBuffer::unmap()
 {
 }
 
 QSize ShmGraphicsBuffer::size() const
 {
     return m_attributes.size;
 }
 
 bool ShmGraphicsBuffer::hasAlphaChannel() const
 {
     return m_hasAlphaChannel;
 }
 
 const ShmAttributes *ShmGraphicsBuffer::shmAttributes() const
 {
     return &m_attributes;
 }
 
 GraphicsBuffer *ShmGraphicsBufferAllocator::allocate(const GraphicsBufferOptions &options)
 {
     if (!options.software) {
         return nullptr;
     }
     if (!options.modifiers.isEmpty() && !options.modifiers.contains(DRM_FORMAT_MOD_LINEAR)) {
         return nullptr;
     }
 
     switch (options.format) {
     case DRM_FORMAT_ARGB8888:
     case DRM_FORMAT_XRGB8888:
         break;
     default:
         return nullptr;
     }
 
     const int stride = options.size.width() * 4;
     const int bufferSize = options.size.height() * stride;
 
 #if HAVE_MEMFD
     FileDescriptor fd = FileDescriptor(memfd_create("shm", MFD_CLOEXEC | MFD_ALLOW_SEALING));
     if (!fd.isValid()) {
         return nullptr;
     }
 
     if (ftruncate(fd.get(), bufferSize) < 0) {
         return nullptr;
     }
 
     fcntl(fd.get(), F_ADD_SEALS, F_SEAL_SHRINK | F_SEAL_GROW | F_SEAL_SEAL);
 #else
     char templateName[] = "/tmp/kwin-shm-XXXXXX";
     FileDescriptor fd{mkstemp(templateName)};
     if (!fd.isValid()) {
         return nullptr;
     }
 
     unlink(templateName);
     int flags = fcntl(fd.get(), F_GETFD);
     if (flags == -1 || fcntl(fd.get(), F_SETFD, flags | FD_CLOEXEC) == -1) {
         return nullptr;
     }
 
     if (ftruncate(fd.get(), bufferSize) < 0) {
         return nullptr;
     }
 #endif
 
     ShmAttributes attributes{
         .fd = std::move(fd),
         .stride = stride,
         .offset = 0,
         .size = options.size,
         .format = options.format,
     };
 
     MemoryMap memoryMap(attributes.stride * attributes.size.height(), PROT_READ | PROT_WRITE, MAP_SHARED, attributes.fd.get(), attributes.offset);
     if (!memoryMap.isValid()) {
         return nullptr;
     }
 
     return new ShmGraphicsBuffer(std::move(attributes), std::move(memoryMap));
 }
 
 } // namespace KWin
 
 #include "moc_shmgraphicsbufferallocator.cpp"
 #include "shmgraphicsbufferallocator.moc"