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Kernel: Implement /proc/<n>/fd

This commit is contained in:
Bananymous 2025-11-24 00:19:51 +02:00
parent 3207f5d61f
commit 9d0990e5e8
3 changed files with 138 additions and 15 deletions
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45
kernel/include/kernel/FS/ProcFS/Inode.h
View File

@ -69,10 +69,6 @@ namespace Kernel
protected:
virtual BAN::ErrorOr<BAN::String> link_target_impl() override;
// You may not write here and this is always non blocking
virtual BAN::ErrorOr<size_t> write_impl(off_t, BAN::ConstByteSpan) override { return BAN::Error::from_errno(EINVAL); }
virtual BAN::ErrorOr<void> truncate_impl(size_t) override { return BAN::Error::from_errno(EINVAL); }
virtual bool can_read_impl() const override { return false; }
virtual bool can_write_impl() const override { return false; }
virtual bool has_error_impl() const override { return false; }
@ -114,27 +110,54 @@ namespace Kernel
class ProcSymlinkInode final : public TmpInode
{
public:
static BAN::ErrorOr<BAN::RefPtr<ProcSymlinkInode>> create_new(BAN::ErrorOr<BAN::String> (*)(void*), void* data, TmpFileSystem&, mode_t, uid_t, gid_t);
~ProcSymlinkInode() = default;
static BAN::ErrorOr<BAN::RefPtr<ProcSymlinkInode>> create_new(BAN::ErrorOr<BAN::String> (*)(void*), void (*)(void*), void* data, TmpFileSystem&, mode_t, uid_t, gid_t);
~ProcSymlinkInode();
protected:
virtual BAN::ErrorOr<BAN::String> link_target_impl() override;
// You may not write here and this is always non blocking
virtual BAN::ErrorOr<size_t> write_impl(off_t, BAN::ConstByteSpan) override { return BAN::Error::from_errno(EINVAL); }
virtual BAN::ErrorOr<void> truncate_impl(size_t) override { return BAN::Error::from_errno(EINVAL); }
virtual bool can_read_impl() const override { return false; }
virtual bool can_write_impl() const override { return false; }
virtual bool has_error_impl() const override { return false; }
virtual bool has_hungup_impl() const override { return false; }
private:
ProcSymlinkInode(BAN::ErrorOr<BAN::String> (*callback)(void*), void* data, TmpFileSystem&, const TmpInodeInfo&);
ProcSymlinkInode(BAN::ErrorOr<BAN::String> (*callback)(void*), void (*destructor)(void*), void* data, TmpFileSystem&, const TmpInodeInfo&);
private:
BAN::ErrorOr<BAN::String> (*m_callback)(void*);
void (*m_destructor)(void*);
void* m_data;
};
class ProcFDDirectoryInode final : public TmpInode
{
public:
static BAN::ErrorOr<BAN::RefPtr<ProcFDDirectoryInode>> create_new(Process&, TmpFileSystem&, mode_t);
~ProcFDDirectoryInode() = default;
virtual uid_t uid() const override { return m_process.credentials().ruid(); }
virtual gid_t gid() const override { return m_process.credentials().rgid(); }
protected:
virtual BAN::ErrorOr<BAN::RefPtr<Inode>> find_inode_impl(BAN::StringView) override;
virtual BAN::ErrorOr<size_t> list_next_inodes_impl(off_t, struct dirent*, size_t) override;
virtual BAN::ErrorOr<void> create_file_impl(BAN::StringView, mode_t, uid_t, gid_t) override { return BAN::Error::from_errno(EPERM); }
virtual BAN::ErrorOr<void> create_directory_impl(BAN::StringView, mode_t, uid_t, gid_t) override { return BAN::Error::from_errno(EPERM); }
virtual BAN::ErrorOr<void> link_inode_impl(BAN::StringView, BAN::RefPtr<Inode>) override { return BAN::Error::from_errno(EPERM); }
virtual BAN::ErrorOr<void> rename_inode_impl(BAN::RefPtr<Inode>, BAN::StringView, BAN::StringView) override { return BAN::Error::from_errno(EPERM); }
virtual BAN::ErrorOr<void> unlink_impl(BAN::StringView) override { return BAN::Error::from_errno(EPERM); }
virtual bool can_read_impl() const override { return false; }
virtual bool can_write_impl() const override { return false; }
virtual bool has_error_impl() const override { return false; }
virtual bool has_hungup_impl() const override { return false; }
private:
ProcFDDirectoryInode(Process&, TmpFileSystem&, const TmpInodeInfo&);
private:
Process& m_process;
};
}

2
kernel/kernel/FS/ProcFS/FileSystem.cpp
View File

@ -43,7 +43,7 @@ namespace Kernel
[](void*) -> BAN::ErrorOr<BAN::String> {
return BAN::String::formatted("{}", Process::current().pid());
},
nullptr, *s_instance, 0444, 0, 0)
nullptr, nullptr, *s_instance, 0444, 0, 0)
);
MUST(static_cast<TmpDirectoryInode*>(s_instance->root_inode().ptr())->link_inode(*self_inode, "self"_sv));
}

106
kernel/kernel/FS/ProcFS/Inode.cpp
View File

@ -1,5 +1,7 @@
#include <kernel/FS/ProcFS/Inode.h>
#include <ctype.h>
namespace Kernel
{
@ -19,6 +21,7 @@ namespace Kernel
TRY(inode->link_inode(*MUST(ProcROProcessInode::create_new(process, &Process::proc_environ, fs, 0400)), "environ"_sv));
TRY(inode->link_inode(*MUST(ProcSymlinkProcessInode::create_new(process, &Process::proc_cwd, fs, 0777)), "cwd"_sv));
TRY(inode->link_inode(*MUST(ProcSymlinkProcessInode::create_new(process, &Process::proc_exe, fs, 0777)), "exe"_sv));
TRY(inode->link_inode(*MUST(ProcFDDirectoryInode::create_new(process, fs, 0777)), "fd"_sv));
return inode;
}
@ -36,6 +39,7 @@ namespace Kernel
(void)TmpDirectoryInode::unlink_impl("environ"_sv);
(void)TmpDirectoryInode::unlink_impl("cwd"_sv);
(void)TmpDirectoryInode::unlink_impl("exe"_sv);
(void)TmpDirectoryInode::unlink_impl("fd"_sv);
}
BAN::ErrorOr<BAN::RefPtr<ProcROProcessInode>> ProcROProcessInode::create_new(Process& process, size_t (Process::*callback)(off_t, BAN::ByteSpan) const, TmpFileSystem& fs, mode_t mode)
@ -110,27 +114,123 @@ namespace Kernel
return m_callback(offset, buffer);
}
BAN::ErrorOr<BAN::RefPtr<ProcSymlinkInode>> ProcSymlinkInode::create_new(BAN::ErrorOr<BAN::String> (*callback)(void*), void* data, TmpFileSystem& fs, mode_t mode, uid_t uid, gid_t gid)
BAN::ErrorOr<BAN::RefPtr<ProcSymlinkInode>> ProcSymlinkInode::create_new(BAN::ErrorOr<BAN::String> (*callback)(void*), void (*destructor)(void*), void* data, TmpFileSystem& fs, mode_t mode, uid_t uid, gid_t gid)
{
auto inode_info = create_inode_info(Mode::IFLNK | mode, uid, gid);
auto* inode_ptr = new ProcSymlinkInode(callback, data, fs, inode_info);
auto* inode_ptr = new ProcSymlinkInode(callback, destructor, data, fs, inode_info);
if (inode_ptr == nullptr)
return BAN::Error::from_errno(ENOMEM);
return BAN::RefPtr<ProcSymlinkInode>::adopt(inode_ptr);
}
ProcSymlinkInode::ProcSymlinkInode(BAN::ErrorOr<BAN::String> (*callback)(void*), void* data, TmpFileSystem& fs, const TmpInodeInfo& inode_info)
ProcSymlinkInode::ProcSymlinkInode(BAN::ErrorOr<BAN::String> (*callback)(void*), void (*destructor)(void*), void* data, TmpFileSystem& fs, const TmpInodeInfo& inode_info)
: TmpInode(fs, MUST(fs.allocate_inode(inode_info)), inode_info)
, m_callback(callback)
, m_destructor(destructor)
, m_data(data)
{
m_inode_info.mode |= Inode::Mode::IFLNK;
}
ProcSymlinkInode::~ProcSymlinkInode()
{
if (m_destructor)
m_destructor(m_data);
}
BAN::ErrorOr<BAN::String> ProcSymlinkInode::link_target_impl()
{
return m_callback(m_data);
}
BAN::ErrorOr<BAN::RefPtr<ProcFDDirectoryInode>> ProcFDDirectoryInode::create_new(Process& process, TmpFileSystem& fs, mode_t mode)
{
auto inode_info = create_inode_info(Mode::IFDIR | mode, 0, 0);
auto* inode_ptr = new ProcFDDirectoryInode(process, fs, inode_info);
if (inode_ptr == nullptr)
return BAN::Error::from_errno(ENOMEM);
return BAN::RefPtr<ProcFDDirectoryInode>::adopt(inode_ptr);
}
ProcFDDirectoryInode::ProcFDDirectoryInode(Process& process, TmpFileSystem& fs, const TmpInodeInfo& inode_info)
: TmpInode(fs, MUST(fs.allocate_inode(inode_info)), inode_info)
, m_process(process)
{
ASSERT(mode().ifdir());
}
BAN::ErrorOr<BAN::RefPtr<Inode>> ProcFDDirectoryInode::find_inode_impl(BAN::StringView name)
{
int fd = 0;
for (char ch : name)
{
if (!isdigit(ch))
return BAN::Error::from_errno(ENOENT);
fd = (fd * 10) + (ch - '0');
if (fd > OPEN_MAX)
return BAN::Error::from_errno(ENOENT);
}
auto path_or_error = m_process.open_file_descriptor_set().path_of(fd);
if (path_or_error.is_error())
return BAN::Error::from_errno(ENOENT);
auto* data = new BAN::String();
if (data == nullptr)
return BAN::Error::from_errno(ENOMEM);
*data = BAN::move(path_or_error.release_value());
auto inode = TRY(ProcSymlinkInode::create_new(
[](void* data) -> BAN::ErrorOr<BAN::String>
{
BAN::String result;
TRY(result.append(*static_cast<BAN::String*>(data)));
return result;
},
[](void* data) -> void
{
delete static_cast<BAN::String*>(data);
},
data, m_fs, 0777, uid(), gid()
));
return BAN::RefPtr<Inode>(BAN::move(inode));
}
BAN::ErrorOr<size_t> ProcFDDirectoryInode::list_next_inodes_impl(off_t offset, struct dirent* list, size_t list_len)
{
if (list_len == 0)
return BAN::Error::from_errno(ENOBUFS);
auto& ofds = m_process.open_file_descriptor_set();
for (size_t fd = 0; fd < OPEN_MAX; fd++)
{
if (ofds.inode_of(fd).is_error())
continue;
if (offset-- > 0)
continue;
list[0] = {
.d_ino = 0,
.d_type = DT_LNK,
.d_name = {},
};
size_t index = 0;
BAN::Formatter::print(
[&](char ch) {
list[0].d_name[index++] = ch;
list[0].d_name[index] = '\0';
}, "{}", fd
);
return 1;
}
return 0;
}
}