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Kernel: Implement relative file searching in VFS

This commit is contained in:
Bananymous 2024-09-14 19:43:44 +03:00
parent dce2436b2c
commit 6060b39548
2 changed files with 72 additions and 59 deletions
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7
kernel/include/kernel/FS/VirtualFileSystem.h
View File

@ -27,7 +27,12 @@ namespace Kernel
BAN::RefPtr<Inode> inode; BAN::RefPtr<Inode> inode;
BAN::String canonical_path; BAN::String canonical_path;
}; };
BAN::ErrorOr<File> file_from_absolute_path(const Credentials&, BAN::StringView, int);
BAN::ErrorOr<File> file_from_relative_path(const File& parent, const Credentials&, BAN::StringView, int);
BAN::ErrorOr<File> file_from_absolute_path(const Credentials& credentials, BAN::StringView path, int flags)
{
return file_from_relative_path({ .inode = root_inode(), .canonical_path = {} }, credentials, path, flags);
}
private: private:
VirtualFileSystem() = default; VirtualFileSystem() = default;

124
kernel/kernel/FS/VirtualFileSystem.cpp
View File

@ -105,7 +105,7 @@ namespace Kernel
return BAN::Error::from_errno(ENOTDIR); return BAN::Error::from_errno(ENOTDIR);
LockGuard _(m_mutex); LockGuard _(m_mutex);
TRY(m_mount_points.push_back({ file_system, file })); TRY(m_mount_points.emplace_back(file_system, BAN::move(file)));
return {}; return {};
} }
@ -127,81 +127,91 @@ namespace Kernel
return nullptr; return nullptr;
} }
BAN::ErrorOr<VirtualFileSystem::File> VirtualFileSystem::file_from_absolute_path(const Credentials& credentials, BAN::StringView path, int flags) BAN::ErrorOr<VirtualFileSystem::File> VirtualFileSystem::file_from_relative_path(const File& parent, const Credentials& credentials, BAN::StringView path, int flags)
{ {
LockGuard _(m_mutex); LockGuard _(m_mutex);
ASSERT(path.front() == '/'); auto inode = parent.inode;
auto inode = root_inode();
ASSERT(inode); ASSERT(inode);
BAN::String canonical_path; BAN::String canonical_path;
TRY(canonical_path.append(parent.canonical_path));
if (!canonical_path.empty() && canonical_path.back() == '/')
canonical_path.pop_back();
ASSERT(canonical_path.empty() || canonical_path.back() != '/');
BAN::Vector<BAN::String> path_parts; BAN::Vector<BAN::String> path_parts;
{ const auto append_string_view_in_reverse =
auto temp = TRY(path.split('/')); [&path_parts](BAN::StringView path) -> BAN::ErrorOr<void>
for (size_t i = 0; i < temp.size(); i++) {
TRY(path_parts.emplace_back(temp[temp.size() - i - 1])); auto split_path = TRY(path.split('/'));
} split_path.reverse();
for (auto part : split_path)
{
TRY(path_parts.emplace_back());
TRY(path_parts.back().append(part));
}
return {};
};
TRY(append_string_view_in_reverse(path));
size_t link_depth = 0; size_t link_depth = 0;
while (!path_parts.empty()) while (!path_parts.empty())
{ {
const auto& path_part = path_parts.back(); BAN::String path_part = BAN::move(path_parts.back());
auto orig = inode;
if (path_part.empty() || path_part == "."_sv)
{
}
else if (path_part == ".."_sv)
{
if (auto* mount_point = mount_from_root_inode(inode))
inode = TRY(mount_point->host.inode->find_inode(".."_sv));
else
inode = TRY(inode->find_inode(".."_sv));
if (!canonical_path.empty())
{
ASSERT(canonical_path.front() == '/');
while (canonical_path.back() != '/')
canonical_path.pop_back();
canonical_path.pop_back();
}
}
else
{
if (!inode->can_access(credentials, O_SEARCH))
return BAN::Error::from_errno(EACCES);
inode = TRY(inode->find_inode(path_part));
if (auto* mount_point = mount_from_host_inode(inode))
inode = mount_point->target->root_inode();
TRY(canonical_path.push_back('/'));
TRY(canonical_path.append(path_part));
}
path_parts.pop_back(); path_parts.pop_back();
if (inode->mode().iflnk() && (!(flags & O_NOFOLLOW) || !path_parts.empty())) if (path_part.empty() || path_part == "."_sv)
continue;
auto orig = inode;
// resolve file name
{ {
auto target = TRY(inode->link_target()); auto parent_inode = inode;
if (target.empty()) if (path_part == ".."_sv)
if (auto* mount_point = mount_from_root_inode(inode))
parent_inode = mount_point->host.inode;
if (!parent_inode->can_access(credentials, O_SEARCH))
return BAN::Error::from_errno(EACCES);
inode = TRY(parent_inode->find_inode(path_part));
if (path_part == ".."_sv)
{
if (!canonical_path.empty())
{
ASSERT(canonical_path.front() == '/');
while (canonical_path.back() != '/')
canonical_path.pop_back();
canonical_path.pop_back();
}
}
else
{
if (auto* mount_point = mount_from_host_inode(inode))
inode = mount_point->target->root_inode();
TRY(canonical_path.push_back('/'));
TRY(canonical_path.append(path_part));
}
}
if (!inode->mode().iflnk())
continue;
if ((flags & O_NOFOLLOW) && path_parts.empty())
continue;
// resolve symbolic links
{
auto link_target = TRY(inode->link_target());
if (link_target.empty())
return BAN::Error::from_errno(ENOENT); return BAN::Error::from_errno(ENOENT);
if (target.front() == '/') if (link_target.front() == '/')
{ {
inode = root_inode(); inode = root_inode();
canonical_path.clear(); canonical_path.clear();
auto temp = TRY(target.sv().split('/'));
for (size_t i = 0; i < temp.size(); i++)
TRY(path_parts.emplace_back(temp[temp.size() - i - 1]));
} }
else else
{ {
@ -210,12 +220,10 @@ namespace Kernel
while (canonical_path.back() != '/') while (canonical_path.back() != '/')
canonical_path.pop_back(); canonical_path.pop_back();
canonical_path.pop_back(); canonical_path.pop_back();
auto new_parts = TRY(target.sv().split('/'));
for (size_t i = 0; i < new_parts.size(); i++)
TRY(path_parts.emplace_back(new_parts[new_parts.size() - i - 1]));
} }
TRY(append_string_view_in_reverse(link_target.sv()));
link_depth++; link_depth++;
if (link_depth > 100) if (link_depth > 100)
return BAN::Error::from_errno(ELOOP); return BAN::Error::from_errno(ELOOP);