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|
package main
// hostyFS — generic FUSE filesystem backed by a SQLite table.
//
// Supports two tables:
//
// _hosty_fs (mutable user data):
// path TEXT PRIMARY KEY, mode INTEGER, mtime INTEGER, symlink_target TEXT, content BLOB
// Optional column: content_zstd BLOB (detected at mount time via PRAGMA table_info)
//
// _hosty_image_fs (read-only image files, packed by hosty pack):
// path TEXT PRIMARY KEY, mode INTEGER, mtime INTEGER, symlink_target TEXT,
// content BLOB, content_zstd BLOB
//
// The presence of content_zstd is detected at mount time. If present:
// - Reads transparently decompress content_zstd when content is NULL.
// - Writes lazily decompress content_zstd → content, clear content_zstd, then proceed.
//
// Symlinks are stored as rows with mode S_IFLNK and symlink_target non-NULL.
import (
"context"
"fmt"
"hash/fnv"
"io"
"strings"
"sync"
"syscall"
"time"
"github.com/hanwen/go-fuse/v2/fs"
"github.com/hanwen/go-fuse/v2/fuse"
"github.com/klauspost/stdgozstd"
sqlite "zombiezen.com/go/sqlite"
"zombiezen.com/go/sqlite/sqlitex"
)
// =============================================================================
// Schema helpers
// =============================================================================
const hostyFSSchema = `
CREATE TABLE IF NOT EXISTS _hosty_fs (
path TEXT PRIMARY KEY,
mode INTEGER NOT NULL,
mtime INTEGER NOT NULL,
symlink_target TEXT,
content BLOB
)`
const hostyImageFSSchema = `
CREATE TABLE IF NOT EXISTS _hosty_image_fs (
path TEXT PRIMARY KEY,
mode INTEGER NOT NULL,
mtime INTEGER NOT NULL,
symlink_target TEXT,
content BLOB,
content_zstd BLOB
)`
func initHostyFSTable(conn *sqlite.Conn) error {
return sqlitex.ExecuteTransient(conn, hostyFSSchema, nil)
}
func initHostyImageFSTable(conn *sqlite.Conn) error {
return sqlitex.ExecuteTransient(conn, hostyImageFSSchema, nil)
}
// hasColumn returns true if the given table has a column with the given name.
func hasColumn(conn *sqlite.Conn, table, column string) (bool, error) {
found := false
err := sqlitex.Execute(conn,
fmt.Sprintf(`PRAGMA table_info(%s)`, table),
&sqlitex.ExecOptions{
ResultFunc: func(stmt *sqlite.Stmt) error {
if stmt.ColumnText(1) == column {
found = true
}
return nil
},
})
return found, err
}
// =============================================================================
// FSTableConfig — describes which table to mount and its capabilities
// =============================================================================
// FSTableConfig describes the SQLite table to use as a FUSE filesystem.
type FSTableConfig struct {
// TableName is the SQLite table name, e.g. "_hosty_fs" or "_hosty_image_fs".
TableName string
// ReadOnly rejects all writes with EROFS.
ReadOnly bool
// AllowOther passes FUSE's allow_other so users other than the mounting one
// (e.g. a DynamicUser service) can access the filesystem. Requires
// 'user_allow_other' in /etc/fuse.conf.
AllowOther bool
}
// =============================================================================
// Inode number derivation
// =============================================================================
func pathIno(path string) uint64 {
if path == "/" || path == "" {
return 1
}
h := fnv.New64a()
h.Write([]byte(path))
n := h.Sum64()
if n <= 1 {
n = 2
}
return n
}
// =============================================================================
// hostyFSNode
// =============================================================================
type hostyFSNode struct {
fs.Inode
root *hostyFSRoot
path string
}
var _ = (fs.NodeLookuper)((*hostyFSNode)(nil))
var _ = (fs.NodeReaddirer)((*hostyFSNode)(nil))
var _ = (fs.NodeGetattrer)((*hostyFSNode)(nil))
var _ = (fs.NodeCreater)((*hostyFSNode)(nil))
var _ = (fs.NodeMkdirer)((*hostyFSNode)(nil))
var _ = (fs.NodeUnlinker)((*hostyFSNode)(nil))
var _ = (fs.NodeRmdirer)((*hostyFSNode)(nil))
var _ = (fs.NodeRenamer)((*hostyFSNode)(nil))
var _ = (fs.NodeOpener)((*hostyFSNode)(nil))
var _ = (fs.NodeReader)((*hostyFSNode)(nil))
var _ = (fs.NodeWriter)((*hostyFSNode)(nil))
var _ = (fs.NodeSetattrer)((*hostyFSNode)(nil))
var _ = (fs.NodeReadlinker)((*hostyFSNode)(nil))
var _ = (fs.NodeSymlinker)((*hostyFSNode)(nil))
func (n *hostyFSNode) childPath(name string) string {
if n.path == "/" {
return "/" + name
}
return n.path + "/" + name
}
func (n *hostyFSNode) tbl() string { return n.root.cfg.TableName }
// Lookup finds a named child in the table.
func (n *hostyFSNode) Lookup(ctx context.Context, name string, out *fuse.EntryOut) (*fs.Inode, syscall.Errno) {
cp := n.childPath(name)
n.root.mu.Lock()
defer n.root.mu.Unlock()
var mode, mtime, size int64
var symlinkTarget *string
var found bool
err := sqlitex.Execute(n.root.conn,
fmt.Sprintf(`SELECT mode, mtime, length(content), symlink_target FROM %s WHERE path = ?`, n.tbl()),
&sqlitex.ExecOptions{
Args: []any{cp},
ResultFunc: func(stmt *sqlite.Stmt) error {
mode = stmt.ColumnInt64(0)
mtime = stmt.ColumnInt64(1)
size = stmt.ColumnInt64(2)
if stmt.ColumnType(3) != sqlite.TypeNull {
s := stmt.ColumnText(3)
symlinkTarget = &s
size = int64(len(s))
}
found = true
return nil
},
})
if err != nil {
return nil, syscall.EIO
}
if !found {
return nil, syscall.ENOENT
}
// If content is NULL but content_zstd exists, decompress to get real size.
if n.root.hasZstd && size == 0 && symlinkTarget == nil && mode&syscall.S_IFMT == syscall.S_IFREG {
if data, err := readZstdContent(n.root.conn, n.tbl(), cp); err == nil && len(data) > 0 {
size = int64(len(data))
}
}
fillAttr(&out.Attr, mode, mtime, size, symlinkTarget)
out.SetAttrTimeout(0)
out.SetEntryTimeout(0)
stable := fs.StableAttr{Mode: uint32(mode) & syscall.S_IFMT, Ino: pathIno(cp)}
child := n.NewInode(ctx, &hostyFSNode{root: n.root, path: cp}, stable)
return child, 0
}
// Readdir lists direct children.
func (n *hostyFSNode) Readdir(ctx context.Context) (fs.DirStream, syscall.Errno) {
prefix := n.path
if prefix == "/" {
prefix = ""
}
n.root.mu.Lock()
defer n.root.mu.Unlock()
var entries []fuse.DirEntry
err := sqlitex.Execute(n.root.conn,
fmt.Sprintf(`SELECT path, mode FROM %s WHERE path LIKE ? AND path NOT LIKE ?`, n.tbl()),
&sqlitex.ExecOptions{
Args: []any{prefix + "/%", prefix + "/%/%"},
ResultFunc: func(stmt *sqlite.Stmt) error {
p := stmt.ColumnText(0)
mode := stmt.ColumnInt64(1)
name := p[strings.LastIndex(p, "/")+1:]
entries = append(entries, fuse.DirEntry{
Name: name,
Ino: pathIno(p),
Mode: uint32(mode) & syscall.S_IFMT,
})
return nil
},
})
if err != nil {
return nil, syscall.EIO
}
return fs.NewListDirStream(entries), 0
}
// Getattr returns file attributes.
func (n *hostyFSNode) Getattr(ctx context.Context, fh fs.FileHandle, out *fuse.AttrOut) syscall.Errno {
if n.path == "/" {
out.Attr = fuse.Attr{Ino: 1, Mode: syscall.S_IFDIR | 0755, Mtime: uint64(time.Now().Unix()), Nlink: 2}
out.SetTimeout(0)
return 0
}
n.root.mu.Lock()
defer n.root.mu.Unlock()
return n.getattrLocked(out)
}
func (n *hostyFSNode) getattrLocked(out *fuse.AttrOut) syscall.Errno {
var mode, mtime, size int64
var symlinkTarget *string
var found bool
err := sqlitex.Execute(n.root.conn,
fmt.Sprintf(`SELECT mode, mtime, length(content), symlink_target FROM %s WHERE path = ?`, n.tbl()),
&sqlitex.ExecOptions{
Args: []any{n.path},
ResultFunc: func(stmt *sqlite.Stmt) error {
mode = stmt.ColumnInt64(0)
mtime = stmt.ColumnInt64(1)
size = stmt.ColumnInt64(2)
if stmt.ColumnType(3) != sqlite.TypeNull {
s := stmt.ColumnText(3)
symlinkTarget = &s
size = int64(len(s))
}
found = true
return nil
},
})
if err != nil || !found {
return syscall.ENOENT
}
// If content is NULL and content_zstd exists, get real decompressed size.
if n.root.hasZstd && size == 0 && symlinkTarget == nil && mode&syscall.S_IFMT == syscall.S_IFREG {
if data, err := readZstdContent(n.root.conn, n.tbl(), n.path); err == nil {
size = int64(len(data))
}
}
fillAttr(&out.Attr, mode, mtime, size, symlinkTarget)
out.SetTimeout(0)
return 0
}
// Create creates a new regular file.
func (n *hostyFSNode) Create(ctx context.Context, name string, flags uint32, mode uint32, out *fuse.EntryOut) (*fs.Inode, fs.FileHandle, uint32, syscall.Errno) {
if n.root.cfg.ReadOnly {
return nil, nil, 0, syscall.EROFS
}
cp := n.childPath(name)
now := time.Now().Unix()
fileMode := int64((mode &^ syscall.S_IFMT) | syscall.S_IFREG)
n.root.mu.Lock()
defer n.root.mu.Unlock()
err := sqlitex.Execute(n.root.conn,
fmt.Sprintf(`INSERT INTO %s (path, mode, mtime, content) VALUES (?, ?, ?, X'')`, n.tbl()),
&sqlitex.ExecOptions{Args: []any{cp, fileMode, now}})
if err != nil {
return nil, nil, 0, syscall.EIO
}
out.Attr = fuse.Attr{Ino: pathIno(cp), Mode: uint32(fileMode), Mtime: uint64(now), Nlink: 1}
out.SetAttrTimeout(0)
out.SetEntryTimeout(0)
child := n.NewInode(ctx, &hostyFSNode{root: n.root, path: cp},
fs.StableAttr{Mode: syscall.S_IFREG, Ino: pathIno(cp)})
return child, &hostyFileHandle{root: n.root, path: cp}, 0, 0
}
// Mkdir creates a directory.
func (n *hostyFSNode) Mkdir(ctx context.Context, name string, mode uint32, out *fuse.EntryOut) (*fs.Inode, syscall.Errno) {
if n.root.cfg.ReadOnly {
return nil, syscall.EROFS
}
cp := n.childPath(name)
now := time.Now().Unix()
dirMode := int64((mode &^ syscall.S_IFMT) | syscall.S_IFDIR)
n.root.mu.Lock()
defer n.root.mu.Unlock()
err := sqlitex.Execute(n.root.conn,
fmt.Sprintf(`INSERT INTO %s (path, mode, mtime) VALUES (?, ?, ?)`, n.tbl()),
&sqlitex.ExecOptions{Args: []any{cp, dirMode, now}})
if err != nil {
return nil, syscall.EIO
}
out.Attr = fuse.Attr{Ino: pathIno(cp), Mode: uint32(dirMode), Mtime: uint64(now), Nlink: 2}
out.SetAttrTimeout(0)
out.SetEntryTimeout(0)
child := n.NewInode(ctx, &hostyFSNode{root: n.root, path: cp},
fs.StableAttr{Mode: syscall.S_IFDIR, Ino: pathIno(cp)})
return child, 0
}
// Symlink creates a symlink.
func (n *hostyFSNode) Symlink(ctx context.Context, target, name string, out *fuse.EntryOut) (*fs.Inode, syscall.Errno) {
if n.root.cfg.ReadOnly {
return nil, syscall.EROFS
}
cp := n.childPath(name)
now := time.Now().Unix()
mode := int64(syscall.S_IFLNK | 0777)
n.root.mu.Lock()
defer n.root.mu.Unlock()
err := sqlitex.Execute(n.root.conn,
fmt.Sprintf(`INSERT INTO %s (path, mode, mtime, symlink_target) VALUES (?, ?, ?, ?)`, n.tbl()),
&sqlitex.ExecOptions{Args: []any{cp, mode, now, target}})
if err != nil {
return nil, syscall.EIO
}
out.Attr = fuse.Attr{Ino: pathIno(cp), Mode: uint32(mode), Mtime: uint64(now), Nlink: 1, Size: uint64(len(target))}
out.SetAttrTimeout(0)
out.SetEntryTimeout(0)
child := n.NewInode(ctx, &hostyFSNode{root: n.root, path: cp},
fs.StableAttr{Mode: syscall.S_IFLNK, Ino: pathIno(cp)})
return child, 0
}
// Readlink returns the symlink target.
func (n *hostyFSNode) Readlink(ctx context.Context) ([]byte, syscall.Errno) {
n.root.mu.Lock()
defer n.root.mu.Unlock()
var target string
var found bool
err := sqlitex.Execute(n.root.conn,
fmt.Sprintf(`SELECT symlink_target FROM %s WHERE path = ?`, n.tbl()),
&sqlitex.ExecOptions{
Args: []any{n.path},
ResultFunc: func(stmt *sqlite.Stmt) error {
target = stmt.ColumnText(0)
found = true
return nil
},
})
if err != nil || !found {
return nil, syscall.ENOENT
}
return []byte(target), 0
}
// Unlink removes a regular file or symlink.
func (n *hostyFSNode) Unlink(ctx context.Context, name string) syscall.Errno {
if n.root.cfg.ReadOnly {
return syscall.EROFS
}
cp := n.childPath(name)
n.root.mu.Lock()
defer n.root.mu.Unlock()
err := sqlitex.Execute(n.root.conn,
fmt.Sprintf(`DELETE FROM %s WHERE path = ?`, n.tbl()),
&sqlitex.ExecOptions{Args: []any{cp}})
if err != nil {
return syscall.EIO
}
if n.root.conn.Changes() == 0 {
return syscall.ENOENT
}
return 0
}
// Rmdir removes an empty directory.
func (n *hostyFSNode) Rmdir(ctx context.Context, name string) syscall.Errno {
if n.root.cfg.ReadOnly {
return syscall.EROFS
}
cp := n.childPath(name)
n.root.mu.Lock()
defer n.root.mu.Unlock()
var mode int64
var found bool
if err := sqlitex.Execute(n.root.conn,
fmt.Sprintf(`SELECT mode FROM %s WHERE path = ?`, n.tbl()),
&sqlitex.ExecOptions{
Args: []any{cp},
ResultFunc: func(stmt *sqlite.Stmt) error {
mode = stmt.ColumnInt64(0)
found = true
return nil
},
}); err != nil || !found {
return syscall.ENOENT
}
if mode&syscall.S_IFMT != syscall.S_IFDIR {
return syscall.ENOTDIR
}
var count int64
if err := sqlitex.Execute(n.root.conn,
fmt.Sprintf(`SELECT COUNT(*) FROM %s WHERE path LIKE ?`, n.tbl()),
&sqlitex.ExecOptions{
Args: []any{cp + "/%"},
ResultFunc: func(stmt *sqlite.Stmt) error {
count = stmt.ColumnInt64(0)
return nil
},
}); err != nil {
return syscall.EIO
}
if count > 0 {
return syscall.ENOTEMPTY
}
if err := sqlitex.Execute(n.root.conn,
fmt.Sprintf(`DELETE FROM %s WHERE path = ?`, n.tbl()),
&sqlitex.ExecOptions{Args: []any{cp}}); err != nil {
return syscall.EIO
}
return 0
}
// Rename renames a file or directory.
func (n *hostyFSNode) Rename(ctx context.Context, name string, newParent fs.InodeEmbedder, newName string, flags uint32) syscall.Errno {
if n.root.cfg.ReadOnly {
return syscall.EROFS
}
oldPath := n.childPath(name)
newParentNode, ok := newParent.(*hostyFSNode)
if !ok {
return syscall.EINVAL
}
newPath := newParentNode.childPath(newName)
if oldPath == newPath {
return 0
}
n.root.mu.Lock()
defer n.root.mu.Unlock()
var srcMode int64
var found bool
if err := sqlitex.Execute(n.root.conn,
fmt.Sprintf(`SELECT mode FROM %s WHERE path = ?`, n.tbl()),
&sqlitex.ExecOptions{
Args: []any{oldPath},
ResultFunc: func(stmt *sqlite.Stmt) error {
srcMode = stmt.ColumnInt64(0)
found = true
return nil
},
}); err != nil || !found {
return syscall.ENOENT
}
if err := sqlitex.Execute(n.root.conn, `BEGIN IMMEDIATE`, nil); err != nil {
return syscall.EIO
}
doRename := func() syscall.Errno {
if srcMode&syscall.S_IFMT == syscall.S_IFDIR {
var paths []string
if err := sqlitex.Execute(n.root.conn,
fmt.Sprintf(`SELECT path FROM %s WHERE path = ? OR path LIKE ?`, n.tbl()),
&sqlitex.ExecOptions{
Args: []any{oldPath, oldPath + "/%"},
ResultFunc: func(stmt *sqlite.Stmt) error {
paths = append(paths, stmt.ColumnText(0))
return nil
},
}); err != nil {
return syscall.EIO
}
for _, p := range paths {
updated := newPath + p[len(oldPath):]
if err := sqlitex.Execute(n.root.conn,
fmt.Sprintf(`UPDATE %s SET path = ? WHERE path = ?`, n.tbl()),
&sqlitex.ExecOptions{Args: []any{updated, p}}); err != nil {
return syscall.EIO
}
}
} else {
if err := sqlitex.Execute(n.root.conn,
fmt.Sprintf(`UPDATE %s SET path = ? WHERE path = ?`, n.tbl()),
&sqlitex.ExecOptions{Args: []any{newPath, oldPath}}); err != nil {
return syscall.EIO
}
}
return 0
}
errno := doRename()
if errno != 0 {
_ = sqlitex.Execute(n.root.conn, `ROLLBACK`, nil)
return errno
}
if err := sqlitex.Execute(n.root.conn, `COMMIT`, nil); err != nil {
return syscall.EIO
}
return 0
}
// Open returns a file handle.
func (n *hostyFSNode) Open(ctx context.Context, flags uint32) (fs.FileHandle, uint32, syscall.Errno) {
return &hostyFileHandle{root: n.root, path: n.path}, 0, 0
}
func (n *hostyFSNode) Read(ctx context.Context, fh fs.FileHandle, dest []byte, off int64) (fuse.ReadResult, syscall.Errno) {
if h, ok := fh.(*hostyFileHandle); ok {
return h.Read(ctx, dest, off)
}
return (&hostyFileHandle{root: n.root, path: n.path}).Read(ctx, dest, off)
}
func (n *hostyFSNode) Write(ctx context.Context, fh fs.FileHandle, buf []byte, off int64) (uint32, syscall.Errno) {
if n.root.cfg.ReadOnly {
return 0, syscall.EROFS
}
if h, ok := fh.(*hostyFileHandle); ok {
return h.Write(ctx, buf, off)
}
return (&hostyFileHandle{root: n.root, path: n.path}).Write(ctx, buf, off)
}
func (n *hostyFSNode) Setattr(ctx context.Context, fh fs.FileHandle, in *fuse.SetAttrIn, out *fuse.AttrOut) syscall.Errno {
if n.root.cfg.ReadOnly {
return syscall.EROFS
}
if h, ok := fh.(*hostyFileHandle); ok {
return h.Setattr(ctx, in, out)
}
return (&hostyFileHandle{root: n.root, path: n.path}).Setattr(ctx, in, out)
}
// =============================================================================
// hostyFileHandle
// =============================================================================
type hostyFileHandle struct {
root *hostyFSRoot
path string
}
var _ = (fs.FileReader)((*hostyFileHandle)(nil))
var _ = (fs.FileWriter)((*hostyFileHandle)(nil))
var _ = (fs.FileFlusher)((*hostyFileHandle)(nil))
var _ = (fs.FileReleaser)((*hostyFileHandle)(nil))
var _ = (fs.FileGetattrer)((*hostyFileHandle)(nil))
var _ = (fs.FileSetattrer)((*hostyFileHandle)(nil))
func (fh *hostyFileHandle) tbl() string { return fh.root.cfg.TableName }
// ensureRawContent lazily decompresses content_zstd → content if needed.
// Must be called with root.mu held.
func (fh *hostyFileHandle) ensureRawContent(ctx context.Context) error {
if !fh.root.hasZstd {
return nil
}
var needsDecompress bool
_ = sqlitex.Execute(fh.root.conn,
fmt.Sprintf(`SELECT content IS NULL AND content_zstd IS NOT NULL FROM %s WHERE path = ?`, fh.tbl()),
&sqlitex.ExecOptions{
Args: []any{fh.path},
ResultFunc: func(stmt *sqlite.Stmt) error {
needsDecompress = stmt.ColumnInt64(0) == 1
return nil
},
})
if !needsDecompress {
return nil
}
data, err := readZstdContent(fh.root.conn, fh.tbl(), fh.path)
if err != nil {
return fmt.Errorf("decompressing content_zstd for %s: %w", fh.path, err)
}
return sqlitex.Execute(fh.root.conn,
fmt.Sprintf(`UPDATE %s SET content = ?, content_zstd = NULL WHERE path = ?`, fh.tbl()),
&sqlitex.ExecOptions{Args: []any{data, fh.path}})
}
func (fh *hostyFileHandle) rowid() (int64, error) {
var id int64
err := sqlitex.Execute(fh.root.conn,
fmt.Sprintf(`SELECT rowid FROM %s WHERE path = ?`, fh.tbl()),
&sqlitex.ExecOptions{
Args: []any{fh.path},
ResultFunc: func(stmt *sqlite.Stmt) error {
id = stmt.ColumnInt64(0)
return nil
},
})
return id, err
}
func (fh *hostyFileHandle) Read(ctx context.Context, dest []byte, off int64) (fuse.ReadResult, syscall.Errno) {
fh.root.mu.Lock()
defer fh.root.mu.Unlock()
// If content_zstd present and content is NULL, serve decompressed data directly
// without mutating the DB (works for read-only tables too).
if fh.root.hasZstd {
data, err := readZstdContent(fh.root.conn, fh.tbl(), fh.path)
if err != nil {
return nil, syscall.EIO
}
if data != nil {
if off >= int64(len(data)) {
return fuse.ReadResultData([]byte{}), 0
}
end := min(off+int64(len(dest)), int64(len(data)))
return fuse.ReadResultData(data[off:end]), 0
}
}
// Normal raw content read via blob API.
var size int64
_ = sqlitex.Execute(fh.root.conn,
fmt.Sprintf(`SELECT length(content) FROM %s WHERE path = ?`, fh.tbl()),
&sqlitex.ExecOptions{
Args: []any{fh.path},
ResultFunc: func(stmt *sqlite.Stmt) error {
size = stmt.ColumnInt64(0)
return nil
},
})
if off >= size {
return fuse.ReadResultData([]byte{}), 0
}
rowid, err := fh.rowid()
if err != nil {
return nil, syscall.EIO
}
blob, err := fh.root.conn.OpenBlob("main", fh.tbl(), "content", rowid, false)
if err != nil {
return nil, syscall.EIO
}
defer blob.Close()
if _, err := blob.Seek(off, io.SeekStart); err != nil {
return nil, syscall.EIO
}
toRead := int64(len(dest))
if off+toRead > size {
toRead = size - off
}
buf := make([]byte, toRead)
if _, err := io.ReadFull(blob, buf); err != nil {
return nil, syscall.EIO
}
return fuse.ReadResultData(buf), 0
}
func (fh *hostyFileHandle) Write(ctx context.Context, buf []byte, off int64) (uint32, syscall.Errno) {
if fh.root.cfg.ReadOnly {
return 0, syscall.EROFS
}
fh.root.mu.Lock()
defer fh.root.mu.Unlock()
if err := fh.ensureRawContent(ctx); err != nil {
return 0, syscall.EIO
}
var currentSize, rowid int64
_ = sqlitex.Execute(fh.root.conn,
fmt.Sprintf(`SELECT rowid, length(content) FROM %s WHERE path = ?`, fh.tbl()),
&sqlitex.ExecOptions{
Args: []any{fh.path},
ResultFunc: func(stmt *sqlite.Stmt) error {
rowid = stmt.ColumnInt64(0)
currentSize = stmt.ColumnInt64(1)
return nil
},
})
end := off + int64(len(buf))
if end > currentSize {
extension := end - currentSize
_ = sqlitex.Execute(fh.root.conn,
fmt.Sprintf(`UPDATE %s SET content = content || zeroblob(?) WHERE path = ?`, fh.tbl()),
&sqlitex.ExecOptions{Args: []any{extension, fh.path}})
}
blob, err := fh.root.conn.OpenBlob("main", fh.tbl(), "content", rowid, true)
if err != nil {
return 0, syscall.EIO
}
if _, err := blob.Seek(off, io.SeekStart); err != nil {
blob.Close()
return 0, syscall.EIO
}
n, err := blob.Write(buf)
blob.Close()
if err != nil {
return 0, syscall.EIO
}
_ = sqlitex.Execute(fh.root.conn,
fmt.Sprintf(`UPDATE %s SET mtime = ? WHERE path = ?`, fh.tbl()),
&sqlitex.ExecOptions{Args: []any{time.Now().Unix(), fh.path}})
return uint32(n), 0
}
func (fh *hostyFileHandle) Flush(ctx context.Context) syscall.Errno { return 0 }
func (fh *hostyFileHandle) Release(ctx context.Context) syscall.Errno { return 0 }
func (fh *hostyFileHandle) Getattr(ctx context.Context, out *fuse.AttrOut) syscall.Errno {
fh.root.mu.Lock()
defer fh.root.mu.Unlock()
return (&hostyFSNode{root: fh.root, path: fh.path}).getattrLocked(out)
}
func (fh *hostyFileHandle) Setattr(ctx context.Context, in *fuse.SetAttrIn, out *fuse.AttrOut) syscall.Errno {
fh.root.mu.Lock()
defer fh.root.mu.Unlock()
if sz, ok := in.GetSize(); ok {
if err := fh.ensureRawContent(ctx); err != nil {
return syscall.EIO
}
now := time.Now().Unix()
var currentSize int64
_ = sqlitex.Execute(fh.root.conn,
fmt.Sprintf(`SELECT length(content) FROM %s WHERE path = ?`, fh.tbl()),
&sqlitex.ExecOptions{
Args: []any{fh.path},
ResultFunc: func(stmt *sqlite.Stmt) error {
currentSize = stmt.ColumnInt64(0)
return nil
},
})
if int64(sz) != currentSize {
var err error
if int64(sz) < currentSize {
err = sqlitex.Execute(fh.root.conn,
fmt.Sprintf(`UPDATE %s SET content = substr(content, 1, ?), mtime = ? WHERE path = ?`, fh.tbl()),
&sqlitex.ExecOptions{Args: []any{int64(sz), now, fh.path}})
} else {
extension := int64(sz) - currentSize
err = sqlitex.Execute(fh.root.conn,
fmt.Sprintf(`UPDATE %s SET content = content || zeroblob(?), mtime = ? WHERE path = ?`, fh.tbl()),
&sqlitex.ExecOptions{Args: []any{extension, now, fh.path}})
}
if err != nil {
return syscall.EIO
}
}
}
return (&hostyFSNode{root: fh.root, path: fh.path}).getattrLocked(out)
}
// =============================================================================
// hostyFSRoot
// =============================================================================
type hostyFSRoot struct {
hostyFSNode
conn *sqlite.Conn
mu sync.Mutex
cfg FSTableConfig
hasZstd bool
}
var _ = (fs.NodeOnAdder)((*hostyFSRoot)(nil))
func (r *hostyFSRoot) OnAdd(ctx context.Context) {}
func (r *hostyFSRoot) Getattr(ctx context.Context, fh fs.FileHandle, out *fuse.AttrOut) syscall.Errno {
out.Attr = fuse.Attr{Ino: 1, Mode: syscall.S_IFDIR | 0755, Mtime: uint64(time.Now().Unix()), Nlink: 2}
out.SetTimeout(0)
return 0
}
// =============================================================================
// Mount functions
// =============================================================================
// mountHostyFSTable mounts any hosty FS table at mountDir.
func mountHostyFSTable(dbPath, mountDir string, cfg FSTableConfig) (*fuse.Server, error) {
conn, err := sqlite.OpenConn(dbPath, sqlite.OpenReadWrite|sqlite.OpenWAL)
if err != nil {
return nil, err
}
conn.SetBusyTimeout(5 * time.Second)
switch cfg.TableName {
case "_hosty_fs":
if err := initHostyFSTable(conn); err != nil {
conn.Close()
return nil, err
}
case "_hosty_image_fs":
if err := initHostyImageFSTable(conn); err != nil {
conn.Close()
return nil, err
}
}
hasZstd, err := hasColumn(conn, cfg.TableName, "content_zstd")
if err != nil {
conn.Close()
return nil, fmt.Errorf("probing %s schema: %w", cfg.TableName, err)
}
root := &hostyFSRoot{cfg: cfg, conn: conn, hasZstd: hasZstd}
root.root = root
root.path = "/"
timeout := time.Duration(0)
server, err := fs.Mount(mountDir, root, &fs.Options{
AttrTimeout: &timeout,
EntryTimeout: &timeout,
MountOptions: fuse.MountOptions{
Name: "hosty",
FsName: "hosty",
DisableXAttrs: true,
AllowOther: cfg.AllowOther,
},
})
if err != nil {
conn.Close()
return nil, err
}
return server, nil
}
// mountHostyFS mounts _hosty_fs (mutable user data) at mountDir.
func mountHostyFS(dbPath, mountDir string) (*fuse.Server, error) {
return mountHostyFSOpts(dbPath, mountDir, false)
}
// mountHostyFSOpts mounts _hosty_fs, optionally with FUSE allow_other so a
// service running as a different user (DynamicUser) can access it.
func mountHostyFSOpts(dbPath, mountDir string, allowOther bool) (*fuse.Server, error) {
return mountHostyFSTable(dbPath, mountDir, FSTableConfig{
TableName: "_hosty_fs",
ReadOnly: false,
AllowOther: allowOther,
})
}
// =============================================================================
// zstd helpers
// =============================================================================
var (
zstdDecoder, _ = zstd.NewReader(nil)
zstdEncoder = zstd.NewWriter(nil)
)
func zstdDecompress(data []byte) ([]byte, error) {
return zstdDecoder.AppendDecompress(nil, data)
}
func zstdCompress(data []byte) []byte {
return zstdEncoder.AppendCompress(nil, data)
}
// readZstdContent reads the content_zstd column and decompresses it.
// Returns nil, nil if the row has raw content instead of content_zstd, or if content_zstd is NULL.
// Caller must hold root.mu.
func readZstdContent(conn *sqlite.Conn, table, path string) ([]byte, error) {
var compressed []byte
_ = sqlitex.Execute(conn,
fmt.Sprintf(`SELECT content_zstd FROM %s WHERE path = ? AND content IS NULL AND content_zstd IS NOT NULL`, table),
&sqlitex.ExecOptions{
Args: []any{path},
ResultFunc: func(stmt *sqlite.Stmt) error {
r := stmt.ColumnReader(0)
compressed = make([]byte, r.Len())
r.Read(compressed)
return nil
},
})
if compressed == nil {
return nil, nil
}
return zstdDecompress(compressed)
}
// readContentFromTable reads the content of a file row, decompressing if needed.
// Used by extractImageFS in main.go.
func readContentFromTable(conn *sqlite.Conn, table, path string) ([]byte, error) {
var content []byte
var compressed []byte
err := sqlitex.Execute(conn,
fmt.Sprintf(`SELECT content, content_zstd FROM %s WHERE path = ?`, table),
&sqlitex.ExecOptions{
Args: []any{path},
ResultFunc: func(stmt *sqlite.Stmt) error {
if stmt.ColumnType(0) != sqlite.TypeNull {
r := stmt.ColumnReader(0)
content = make([]byte, r.Len())
r.Read(content)
}
if stmt.ColumnType(1) != sqlite.TypeNull {
r := stmt.ColumnReader(1)
compressed = make([]byte, r.Len())
r.Read(compressed)
}
return nil
},
})
if err != nil {
return nil, err
}
if len(content) > 0 {
return content, nil
}
if len(compressed) > 0 {
return zstdDecompress(compressed)
}
return []byte{}, nil
}
// =============================================================================
// fillAttr helper
// =============================================================================
func fillAttr(a *fuse.Attr, mode, mtime, size int64, symlinkTarget *string) {
a.Mode = uint32(mode)
a.Mtime = uint64(mtime)
a.Nlink = 1
if mode&syscall.S_IFMT == syscall.S_IFDIR {
a.Nlink = 2
}
if symlinkTarget != nil {
a.Size = uint64(len(*symlinkTarget))
} else if size > 0 {
a.Size = uint64(size)
a.Blocks = (a.Size + 511) / 512
}
}
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