1 files changed, 259 insertions, 0 deletions
diff --git a/vendor/github.com/ncruces/go-sqlite3/vfs/shm_bsd.go b/vendor/github.com/ncruces/go-sqlite3/vfs/shm_bsd.go
new file mode 100644
index 000000000..3b45b3087
--- /dev/null
+++ b/vendor/github.com/ncruces/go-sqlite3/vfs/shm_bsd.go
@@ -0,0 +1,259 @@
+//go:build (freebsd || openbsd || netbsd || dragonfly || illumos || sqlite3_flock) && (amd64 || arm64 || riscv64) && !(sqlite3_noshm || sqlite3_nosys)
+
+package vfs
+
+import (
+	"context"
+	"io"
+	"os"
+	"sync"
+
+	"github.com/ncruces/go-sqlite3/internal/util"
+	"github.com/tetratelabs/wazero/api"
+	"golang.org/x/sys/unix"
+)
+
+// SupportsSharedMemory is false on platforms that do not support shared memory.
+// To use [WAL without shared-memory], you need to set [EXCLUSIVE locking mode].
+//
+// [WAL without shared-memory]: https://sqlite.org/wal.html#noshm
+// [EXCLUSIVE locking mode]: https://sqlite.org/pragma.html#pragma_locking_mode
+const SupportsSharedMemory = true
+
+const _SHM_NLOCK = 8
+
+func (f *vfsFile) SharedMemory() SharedMemory { return f.shm }
+
+// NewSharedMemory returns a shared-memory WAL-index
+// backed by a file with the given path.
+// It will return nil if shared-memory is not supported,
+// or not appropriate for the given flags.
+// Only [OPEN_MAIN_DB] databases may need a WAL-index.
+// You must ensure all concurrent accesses to a database
+// use shared-memory instances created with the same path.
+func NewSharedMemory(path string, flags OpenFlag) SharedMemory {
+	if flags&OPEN_MAIN_DB == 0 || flags&(OPEN_DELETEONCLOSE|OPEN_MEMORY) != 0 {
+		return nil
+	}
+	return &vfsShm{
+		path:     path,
+		readOnly: flags&OPEN_READONLY != 0,
+	}
+}
+
+type vfsShmFile struct {
+	*os.File
+	info os.FileInfo
+
+	// +checklocks:vfsShmFilesMtx
+	refs int
+
+	// +checklocks:lockMtx
+	lock    [_SHM_NLOCK]int16
+	lockMtx sync.Mutex
+}
+
+var (
+	// +checklocks:vfsShmFilesMtx
+	vfsShmFiles    []*vfsShmFile
+	vfsShmFilesMtx sync.Mutex
+)
+
+type vfsShm struct {
+	*vfsShmFile
+	path     string
+	lock     [_SHM_NLOCK]bool
+	regions  []*util.MappedRegion
+	readOnly bool
+}
+
+func (s *vfsShm) Close() error {
+	if s.vfsShmFile == nil {
+		return nil
+	}
+
+	// Unlock everything.
+	s.shmLock(0, _SHM_NLOCK, _SHM_UNLOCK)
+
+	vfsShmFilesMtx.Lock()
+	defer vfsShmFilesMtx.Unlock()
+
+	// Decrease reference count.
+	if s.vfsShmFile.refs > 1 {
+		s.vfsShmFile.refs--
+		s.vfsShmFile = nil
+		return nil
+	}
+	for i, g := range vfsShmFiles {
+		if g == s.vfsShmFile {
+			vfsShmFiles[i] = nil
+			break
+		}
+	}
+
+	err := s.File.Close()
+	s.vfsShmFile = nil
+	return err
+}
+
+func (s *vfsShm) shmOpen() (rc _ErrorCode) {
+	if s.vfsShmFile != nil {
+		return _OK
+	}
+
+	// Open file read-write, as it will be shared.
+	f, err := os.OpenFile(s.path,
+		unix.O_RDWR|unix.O_CREAT|unix.O_NOFOLLOW, 0666)
+	if err != nil {
+		return _CANTOPEN
+	}
+	// Close if file if it's not nil.
+	defer func() { f.Close() }()
+
+	fi, err := f.Stat()
+	if err != nil {
+		return _IOERR_FSTAT
+	}
+
+	vfsShmFilesMtx.Lock()
+	defer vfsShmFilesMtx.Unlock()
+
+	// Find a shared file, increase the reference count.
+	for _, g := range vfsShmFiles {
+		if g != nil && os.SameFile(fi, g.info) {
+			g.refs++
+			s.vfsShmFile = g
+			return _OK
+		}
+	}
+
+	// Lock and truncate the file, if not readonly.
+	if s.readOnly {
+		rc = _READONLY_CANTINIT
+	} else {
+		if rc := osWriteLock(f, 0, 0, 0); rc != _OK {
+			return rc
+		}
+		if err := f.Truncate(0); err != nil {
+			return _IOERR_SHMOPEN
+		}
+	}
+
+	// Add the new shared file.
+	s.vfsShmFile = &vfsShmFile{
+		File: f,
+		info: fi,
+		refs: 1,
+	}
+	f = nil
+	add := true
+	for i, g := range vfsShmFiles {
+		if g == nil {
+			vfsShmFiles[i] = s.vfsShmFile
+			add = false
+		}
+	}
+	if add {
+		vfsShmFiles = append(vfsShmFiles, s.vfsShmFile)
+	}
+	return rc
+}
+
+func (s *vfsShm) shmMap(ctx context.Context, mod api.Module, id, size int32, extend bool) (uint32, _ErrorCode) {
+	// Ensure size is a multiple of the OS page size.
+	if int(size)&(unix.Getpagesize()-1) != 0 {
+		return 0, _IOERR_SHMMAP
+	}
+
+	if rc := s.shmOpen(); rc != _OK {
+		return 0, rc
+	}
+
+	// Check if file is big enough.
+	o, err := s.Seek(0, io.SeekEnd)
+	if err != nil {
+		return 0, _IOERR_SHMSIZE
+	}
+	if n := (int64(id) + 1) * int64(size); n > o {
+		if !extend {
+			return 0, _OK
+		}
+		err := osAllocate(s.File, n)
+		if err != nil {
+			return 0, _IOERR_SHMSIZE
+		}
+	}
+
+	var prot int
+	if s.readOnly {
+		prot = unix.PROT_READ
+	} else {
+		prot = unix.PROT_READ | unix.PROT_WRITE
+	}
+	r, err := util.MapRegion(ctx, mod, s.File, int64(id)*int64(size), size, prot)
+	if err != nil {
+		return 0, _IOERR_SHMMAP
+	}
+	s.regions = append(s.regions, r)
+	return r.Ptr, _OK
+}
+
+func (s *vfsShm) shmLock(offset, n int32, flags _ShmFlag) _ErrorCode {
+	s.lockMtx.Lock()
+	defer s.lockMtx.Unlock()
+
+	switch {
+	case flags&_SHM_UNLOCK != 0:
+		for i := offset; i < offset+n; i++ {
+			if s.lock[i] {
+				if s.vfsShmFile.lock[i] <= 0 {
+					s.vfsShmFile.lock[i] = 0
+				} else {
+					s.vfsShmFile.lock[i]--
+				}
+			}
+		}
+	case flags&_SHM_SHARED != 0:
+		for i := offset; i < offset+n; i++ {
+			if s.vfsShmFile.lock[i] < 0 {
+				return _BUSY
+			}
+		}
+		for i := offset; i < offset+n; i++ {
+			s.vfsShmFile.lock[i]++
+			s.lock[i] = true
+		}
+	case flags&_SHM_EXCLUSIVE != 0:
+		for i := offset; i < offset+n; i++ {
+			if s.vfsShmFile.lock[i] != 0 {
+				return _BUSY
+			}
+		}
+		for i := offset; i < offset+n; i++ {
+			s.vfsShmFile.lock[i] = -1
+			s.lock[i] = true
+		}
+	}
+
+	return _OK
+}
+
+func (s *vfsShm) shmUnmap(delete bool) {
+	if s.vfsShmFile == nil {
+		return
+	}
+
+	// Unmap regions.
+	for _, r := range s.regions {
+		r.Unmap()
+	}
+	clear(s.regions)
+	s.regions = s.regions[:0]
+
+	// Close the file.
+	if delete {
+		os.Remove(s.path)
+	}
+	s.Close()
+	s.vfsShmFile = nil
+}