forked from Bananymous/banan-os
115 lines
2.9 KiB
C++
115 lines
2.9 KiB
C++
#include <kernel/FS/Pipe.h>
|
|
#include <kernel/Lock/LockGuard.h>
|
|
#include <kernel/Thread.h>
|
|
#include <kernel/Timer/Timer.h>
|
|
|
|
#include <kernel/Process.h>
|
|
|
|
namespace Kernel
|
|
{
|
|
|
|
BAN::ErrorOr<BAN::RefPtr<Inode>> Pipe::create(const Credentials& credentials)
|
|
{
|
|
Pipe* pipe = new Pipe(credentials);
|
|
if (pipe == nullptr)
|
|
return BAN::Error::from_errno(ENOMEM);
|
|
return BAN::RefPtr<Inode>::adopt(pipe);
|
|
}
|
|
|
|
Pipe::Pipe(const Credentials& credentials)
|
|
: m_uid(credentials.euid())
|
|
, m_gid(credentials.egid())
|
|
{
|
|
timespec current_time = SystemTimer::get().real_time();
|
|
m_atime = current_time;
|
|
m_mtime = current_time;
|
|
m_ctime = current_time;
|
|
}
|
|
|
|
void Pipe::clone_writing()
|
|
{
|
|
[[maybe_unused]] auto old_writing_count = m_writing_count.fetch_add(1);
|
|
ASSERT(old_writing_count > 0);
|
|
}
|
|
|
|
void Pipe::close_writing()
|
|
{
|
|
auto old_writing_count = m_writing_count.fetch_sub(1);
|
|
ASSERT(old_writing_count > 0);
|
|
if (old_writing_count == 1)
|
|
m_thread_blocker.unblock();
|
|
}
|
|
|
|
BAN::ErrorOr<size_t> Pipe::read_impl(off_t, BAN::ByteSpan buffer)
|
|
{
|
|
LockGuard _(m_mutex);
|
|
|
|
while (m_buffer_size == 0)
|
|
{
|
|
if (m_writing_count == 0)
|
|
return 0;
|
|
LockFreeGuard lock_free(m_mutex);
|
|
TRY(Thread::current().block_or_eintr_indefinite(m_thread_blocker));
|
|
}
|
|
|
|
const size_t to_copy = BAN::Math::min<size_t>(buffer.size(), m_buffer_size);
|
|
|
|
if (m_buffer_tail + to_copy <= m_buffer.size())
|
|
memcpy(buffer.data(), m_buffer.data() + m_buffer_tail, to_copy);
|
|
else
|
|
{
|
|
const size_t before_wrap = m_buffer.size() - m_buffer_tail;
|
|
const size_t after_wrap = to_copy - before_wrap;
|
|
memcpy(buffer.data(), m_buffer.data() + m_buffer_tail, before_wrap);
|
|
memcpy(buffer.data() + before_wrap, m_buffer.data(), after_wrap);
|
|
}
|
|
|
|
m_buffer_tail = (m_buffer_tail + to_copy) % m_buffer.size();
|
|
m_buffer_size -= to_copy;
|
|
|
|
m_atime = SystemTimer::get().real_time();
|
|
|
|
m_thread_blocker.unblock();
|
|
|
|
return to_copy;
|
|
}
|
|
|
|
BAN::ErrorOr<size_t> Pipe::write_impl(off_t, BAN::ConstByteSpan buffer)
|
|
{
|
|
LockGuard _(m_mutex);
|
|
|
|
if (buffer.size() > m_buffer.size())
|
|
buffer = buffer.slice(0, m_buffer.size());
|
|
|
|
while (m_buffer.size() - m_buffer_size < buffer.size())
|
|
{
|
|
LockFreeGuard lock_free(m_mutex);
|
|
TRY(Thread::current().block_or_eintr_indefinite(m_thread_blocker));
|
|
}
|
|
|
|
const size_t to_copy = buffer.size();
|
|
const size_t buffer_head = (m_buffer_tail + m_buffer_size) % m_buffer.size();
|
|
|
|
if (buffer_head + to_copy <= m_buffer.size())
|
|
memcpy(m_buffer.data() + buffer_head, buffer.data(), to_copy);
|
|
else
|
|
{
|
|
const size_t before_wrap = m_buffer.size() - buffer_head;
|
|
const size_t after_wrap = to_copy - before_wrap;
|
|
memcpy(m_buffer.data() + buffer_head, buffer.data(), before_wrap);
|
|
memcpy(m_buffer.data(), buffer.data() + before_wrap, after_wrap);
|
|
}
|
|
|
|
m_buffer_size += to_copy;
|
|
|
|
timespec current_time = SystemTimer::get().real_time();
|
|
m_mtime = current_time;
|
|
m_ctime = current_time;
|
|
|
|
m_thread_blocker.unblock();
|
|
|
|
return to_copy;
|
|
}
|
|
|
|
}
|