b8684777e0
This commit adds a new flag, j6_channel_block, and a new flags param to the channel_receive syscall. When the block flag is specified, the caller will block waiting for data on the channel if the channel is empty.
90 lines
1.7 KiB
C++
90 lines
1.7 KiB
C++
#include <string.h>
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#include "assert.h"
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#include "memory.h"
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#include "objects/channel.h"
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#include "objects/thread.h"
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#include "objects/vm_area.h"
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extern obj::vm_area_guarded g_kernel_buffers;
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namespace obj {
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constexpr size_t buffer_bytes = mem::kernel_buffer_pages * mem::frame_size;
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channel::channel() :
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m_len {0},
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m_data {g_kernel_buffers.get_section()},
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m_closed {false},
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m_buffer {reinterpret_cast<uint8_t*>(m_data), buffer_bytes},
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kobject {kobject::type::channel}
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{
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}
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channel::~channel()
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{
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if (!closed()) close();
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}
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size_t
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channel::enqueue(const util::buffer &data)
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{
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util::scoped_lock lock {m_close_lock};
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if (closed()) return 0;
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size_t len = data.count;
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void *buffer = nullptr;
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len = m_buffer.reserve(len, &buffer);
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memcpy(buffer, data.pointer, len);
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m_buffer.commit(len);
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if (len) {
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thread *t = m_queue.pop_next();
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lock.release();
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if (t) t->wake();
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}
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return len;
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}
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size_t
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channel::dequeue(util::buffer buffer, bool block)
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{
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util::scoped_lock lock {m_close_lock};
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if (closed()) return 0;
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void *data = nullptr;
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size_t avail = m_buffer.get_block(&data);
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if (!avail && block) {
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thread &cur = thread::current();
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m_queue.add_thread(&cur);
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lock.release();
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cur.block();
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lock.reacquire();
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avail = m_buffer.get_block(&data);
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}
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size_t len = buffer.count > avail ? avail : buffer.count;
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memcpy(buffer.pointer, data, len);
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m_buffer.consume(len);
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return len;
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}
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void
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channel::close()
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{
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util::scoped_lock lock {m_close_lock};
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m_queue.clear();
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g_kernel_buffers.return_section(m_data);
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m_closed = true;
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}
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} // namespace obj
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