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Kernel: Cleanup and fix pipe 

pipe now sends SIGPIPE and returns EPIPE when writing and no readers are
open
This commit is contained in:
Bananymous 2025-05-29 01:02:22 +03:00
parent 37dea8aee7
commit 4d4fb3b6ec
4 changed files with 58 additions and 41 deletions
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3
kernel/include/kernel/FS/Inode.h
View File

@ -133,6 +133,9 @@ namespace Kernel
void del_epoll(class Epoll*);
void epoll_notify(uint32_t event);
virtual void on_close(int status_flags) { (void)status_flags; }
virtual void on_clone(int status_flags) { (void)status_flags; }
protected:
// Directory API
virtual BAN::ErrorOr<BAN::RefPtr<Inode>> find_inode_impl(BAN::StringView) { return BAN::Error::from_errno(ENOTSUP); }

8
kernel/include/kernel/FS/Pipe.h
View File

@ -13,8 +13,9 @@ namespace Kernel
static BAN::ErrorOr<BAN::RefPtr<Inode>> create(const Credentials&);
virtual bool is_pipe() const override { return true; }
void clone_writing();
void close_writing();
void on_close(int status_flags) override;
void on_clone(int status_flags) override;
virtual ino_t ino() const override { return 0; } // FIXME
virtual Mode mode() const override { return { Mode::IFIFO | Mode::IRUSR | Mode::IWUSR }; }
@ -39,7 +40,7 @@ namespace Kernel
virtual bool can_read_impl() const override { return m_buffer_size > 0; }
virtual bool can_write_impl() const override { return true; }
virtual bool has_error_impl() const override { return false; }
virtual bool has_error_impl() const override { return m_reading_count == 0; }
virtual bool has_hungup_impl() const override { return m_writing_count == 0; }
private:
@ -58,6 +59,7 @@ namespace Kernel
size_t m_buffer_tail { 0 };
BAN::Atomic<uint32_t> m_writing_count { 1 };
BAN::Atomic<uint32_t> m_reading_count { 1 };
};
}

46
kernel/kernel/FS/Pipe.cpp
View File

@ -3,6 +3,7 @@
#include <kernel/Thread.h>
#include <kernel/Timer/Timer.h>
#include <fcntl.h>
#include <sys/epoll.h>
namespace Kernel
@ -26,19 +27,41 @@ namespace Kernel
m_ctime = current_time;
}
void Pipe::clone_writing()
void Pipe::on_clone(int status_flags)
{
[[maybe_unused]] auto old_writing_count = m_writing_count.fetch_add(1);
ASSERT(old_writing_count > 0);
if (status_flags & O_WRONLY)
{
[[maybe_unused]] auto old_writing_count = m_writing_count.fetch_add(1);
ASSERT(old_writing_count > 0);
}
if (status_flags & O_RDONLY)
{
[[maybe_unused]] auto old_reading_count = m_reading_count.fetch_add(1);
ASSERT(old_reading_count > 0);
}
}
void Pipe::close_writing()
void Pipe::on_close(int status_flags)
{
auto old_writing_count = m_writing_count.fetch_sub(1);
ASSERT(old_writing_count > 0);
if (old_writing_count != 1)
return;
epoll_notify(EPOLLHUP);
if (status_flags & O_WRONLY)
{
auto old_writing_count = m_writing_count.fetch_sub(1);
ASSERT(old_writing_count > 0);
if (old_writing_count != 1)
return;
epoll_notify(EPOLLHUP);
}
if (status_flags & O_RDONLY)
{
auto old_reading_count = m_reading_count.fetch_sub(1);
ASSERT(old_reading_count > 0);
if (old_reading_count != 1)
return;
epoll_notify(EPOLLERR);
}
m_thread_blocker.unblock();
}
@ -84,6 +107,11 @@ namespace Kernel
while (m_buffer_size >= m_buffer.size())
{
if (m_reading_count == 0)
{
Thread::current().add_signal(SIGPIPE);
return BAN::Error::from_errno(EPIPE);
}
LockFreeGuard lock_free(m_mutex);
TRY(Thread::current().block_or_eintr_or_timeout_ms(m_thread_blocker, 100, false));
}

42
kernel/kernel/OpenFileDescriptorSet.cpp
View File

@ -43,12 +43,7 @@ namespace Kernel
auto& open_file = m_open_files[fd];
open_file.description = other.m_open_files[fd].description;
open_file.descriptor_flags = other.m_open_files[fd].descriptor_flags;
if (open_file.path() == "<pipe wr>"_sv)
{
ASSERT(open_file.inode()->is_pipe());
static_cast<Pipe*>(open_file.inode().ptr())->clone_writing();
}
open_file.inode()->on_clone(open_file.status_flags());
}
return {};
@ -204,14 +199,10 @@ namespace Kernel
(void)close(fildes2);
m_open_files[fildes2].description = m_open_files[fildes].description;
m_open_files[fildes2].descriptor_flags = 0;
if (m_open_files[fildes2].path() == "<pipe wr>"_sv)
{
ASSERT(m_open_files[fildes2].inode()->is_pipe());
static_cast<Pipe*>(m_open_files[fildes2].inode().ptr())->clone_writing();
}
auto& open_file = m_open_files[fildes2];
open_file.description = m_open_files[fildes].description;
open_file.descriptor_flags = 0;
open_file.inode()->on_clone(open_file.status_flags());
return fildes;
}
@ -229,13 +220,10 @@ namespace Kernel
{
const int new_fd = TRY(get_free_fd());
m_open_files[new_fd].description = m_open_files[fd].description;
m_open_files[new_fd].descriptor_flags = (cmd == F_DUPFD_CLOEXEC) ? O_CLOEXEC : 0;
if (m_open_files[new_fd].path() == "<pipe wr>"_sv)
{
ASSERT(m_open_files[new_fd].inode()->is_pipe());
static_cast<Pipe*>(m_open_files[new_fd].inode().ptr())->clone_writing();
}
auto& open_file = m_open_files[new_fd];
open_file.description = m_open_files[fd].description;
open_file.descriptor_flags = (cmd == F_DUPFD_CLOEXEC) ? O_CLOEXEC : 0;
open_file.inode()->on_clone(open_file.status_flags());
return new_fd;
}
@ -313,14 +301,10 @@ namespace Kernel
TRY(validate_fd(fd));
if (m_open_files[fd].path() == "<pipe wr>"_sv)
{
ASSERT(m_open_files[fd].inode()->is_pipe());
static_cast<Pipe*>(m_open_files[fd].inode().ptr())->close_writing();
}
m_open_files[fd].description.clear();
m_open_files[fd].descriptor_flags = 0;
auto& open_file = m_open_files[fd];
open_file.inode()->on_close(open_file.status_flags());
open_file.description.clear();
open_file.descriptor_flags = 0;
return {};
}