Implement shared memory WAL.

.github/workflows/cross.sh

@@ -17,7 +17,9 @@ echo aix           ; GOOS=aix       GOARCH=ppc64 go build .
 echo js            ; GOOS=js        GOARCH=wasm  go build .
 echo wasip1        ; GOOS=wasip1    GOARCH=wasm  go build .
 echo darwin-flock  ; GOOS=darwin    GOARCH=amd64 go build -tags sqlite3_flock .
+echo darwin-noshm  ; GOOS=darwin    GOARCH=amd64 go build -tags sqlite3_noshm .
 echo darwin-nosys  ; GOOS=darwin    GOARCH=amd64 go build -tags sqlite3_nosys .
+echo linux-noshm   ; GOOS=linux     GOARCH=amd64 go build -tags sqlite3_noshm .
 echo linux-nosys   ; GOOS=linux     GOARCH=amd64 go build -tags sqlite3_nosys .
 echo windows-nosys ; GOOS=windows   GOARCH=amd64 go build -tags sqlite3_nosys .
 echo freebsd-nosys ; GOOS=freebsd   GOARCH=amd64 go build -tags sqlite3_nosys .

.github/workflows/test.yml

@@ -47,6 +47,10 @@ jobs:
       run: go test -v -tags sqlite3_flock ./...
       if: matrix.os == 'macos-latest'
 
+    - name: Test no shared memory
+      run: go test -v -tags sqlite3_noshm ./...
+      if: matrix.os == 'ubuntu-latest'
+
     - name: Test no locks
       run: go test -v -tags sqlite3_nosys ./tests -run TestDB_nolock
 

embed/exports.txt

@@ -1,6 +1,7 @@
 free
 malloc
 malloc_destructor
+aligned_alloc
 sqlite3_anycollseq_init
 sqlite3_backup_finish
 sqlite3_backup_init

go.mod

@@ -5,10 +5,10 @@ go 1.21
 require (
 	github.com/ncruces/julianday v1.0.0
 	github.com/psanford/httpreadat v0.1.0
-	github.com/tetratelabs/wazero v1.7.0
-	golang.org/x/crypto v0.21.0
-	golang.org/x/sync v0.6.0
-	golang.org/x/sys v0.18.0
+	github.com/tetratelabs/wazero v1.7.1-0.20240410111357-a0fbb185447f
+	golang.org/x/crypto v0.22.0
+	golang.org/x/sync v0.7.0
+	golang.org/x/sys v0.19.0
 	golang.org/x/text v0.14.0
 )
 

go.sum

@@ -2,13 +2,13 @@ github.com/ncruces/julianday v1.0.0 h1:fH0OKwa7NWvniGQtxdJRxAgkBMolni2BjDHaWTxqt
 github.com/ncruces/julianday v1.0.0/go.mod h1:Dusn2KvZrrovOMJuOt0TNXL6tB7U2E8kvza5fFc9G7g=
 github.com/psanford/httpreadat v0.1.0 h1:VleW1HS2zO7/4c7c7zNl33fO6oYACSagjJIyMIwZLUE=
 github.com/psanford/httpreadat v0.1.0/go.mod h1:Zg7P+TlBm3bYbyHTKv/EdtSJZn3qwbPwpfZ/I9GKCRE=
-github.com/tetratelabs/wazero v1.7.0 h1:jg5qPydno59wqjpGrHph81lbtHzTrWzwwtD4cD88+hQ=
-github.com/tetratelabs/wazero v1.7.0/go.mod h1:ytl6Zuh20R/eROuyDaGPkp82O9C/DJfXAwJfQ3X6/7Y=
-golang.org/x/crypto v0.21.0 h1:X31++rzVUdKhX5sWmSOFZxx8UW/ldWx55cbf08iNAMA=
-golang.org/x/crypto v0.21.0/go.mod h1:0BP7YvVV9gBbVKyeTG0Gyn+gZm94bibOW5BjDEYAOMs=
-golang.org/x/sync v0.6.0 h1:5BMeUDZ7vkXGfEr1x9B4bRcTH4lpkTkpdh0T/J+qjbQ=
-golang.org/x/sync v0.6.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
-golang.org/x/sys v0.18.0 h1:DBdB3niSjOA/O0blCZBqDefyWNYveAYMNF1Wum0DYQ4=
-golang.org/x/sys v0.18.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+github.com/tetratelabs/wazero v1.7.1-0.20240410111357-a0fbb185447f h1:xJ6F/f7fM1OvnPFSn7Ggf9icswSXoYOYLZbu7aJVQbA=
+github.com/tetratelabs/wazero v1.7.1-0.20240410111357-a0fbb185447f/go.mod h1:ytl6Zuh20R/eROuyDaGPkp82O9C/DJfXAwJfQ3X6/7Y=
+golang.org/x/crypto v0.22.0 h1:g1v0xeRhjcugydODzvb3mEM9SQ0HGp9s/nh3COQ/C30=
+golang.org/x/crypto v0.22.0/go.mod h1:vr6Su+7cTlO45qkww3VDJlzDn0ctJvRgYbC2NvXHt+M=
+golang.org/x/sync v0.7.0 h1:YsImfSBoP9QPYL0xyKJPq0gcaJdG3rInoqxTWbfQu9M=
+golang.org/x/sync v0.7.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
+golang.org/x/sys v0.19.0 h1:q5f1RH2jigJ1MoAWp2KTp3gm5zAGFUTarQZ5U386+4o=
+golang.org/x/sys v0.19.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/text v0.14.0 h1:ScX5w1eTa3QqT8oi6+ziP7dTV1S2+ALU0bI+0zXKWiQ=
 golang.org/x/text v0.14.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU=

go.work.sum

@@ -1,4 +1,8 @@
+golang.org/x/mod v0.8.0 h1:LUYupSeNrTNCGzR/hVBk2NHZO4hXcVaW1k4Qx7rjPx8=
 golang.org/x/mod v0.8.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
+golang.org/x/net v0.21.0 h1:AQyQV4dYCvJ7vGmJyKki9+PBdyvhkSd8EIx/qb0AYv4=
 golang.org/x/net v0.21.0/go.mod h1:bIjVDfnllIU7BJ2DNgfnXvpSvtn8VRwhlsaeUTyUS44=
-golang.org/x/term v0.18.0/go.mod h1:ILwASektA3OnRv7amZ1xhE/KTR+u50pbXfZ03+6Nx58=
+golang.org/x/term v0.19.0 h1:+ThwsDv+tYfnJFhF4L8jITxu1tdTWRTZpdsWgEgjL6Q=
+golang.org/x/term v0.19.0/go.mod h1:2CuTdWZ7KHSQwUzKva0cbMg6q2DMI3Mmxp+gKJbskEk=
+golang.org/x/tools v0.6.0 h1:BOw41kyTf3PuCW1pVQf8+Cyg8pMlkYB1oo9iJ6D/lKM=
 golang.org/x/tools v0.6.0/go.mod h1:Xwgl3UAJ/d3gWutnCtw505GrjyAbvKui8lOU390QaIU=

gormlite/go.mod

@@ -4,13 +4,13 @@ go 1.21
 
 require (
 	github.com/ncruces/go-sqlite3 v0.13.0
-	gorm.io/gorm v1.25.8
+	gorm.io/gorm v1.25.9
 )
 
 require (
 	github.com/jinzhu/inflection v1.0.0 // indirect
 	github.com/jinzhu/now v1.1.5 // indirect
 	github.com/ncruces/julianday v1.0.0 // indirect
 	github.com/tetratelabs/wazero v1.7.0 // indirect
-	golang.org/x/sys v0.18.0 // indirect
+	golang.org/x/sys v0.19.0 // indirect
 )

gormlite/go.sum

@@ -8,9 +8,9 @@ github.com/ncruces/julianday v1.0.0 h1:fH0OKwa7NWvniGQtxdJRxAgkBMolni2BjDHaWTxqt
 github.com/ncruces/julianday v1.0.0/go.mod h1:Dusn2KvZrrovOMJuOt0TNXL6tB7U2E8kvza5fFc9G7g=
 github.com/tetratelabs/wazero v1.7.0 h1:jg5qPydno59wqjpGrHph81lbtHzTrWzwwtD4cD88+hQ=
 github.com/tetratelabs/wazero v1.7.0/go.mod h1:ytl6Zuh20R/eROuyDaGPkp82O9C/DJfXAwJfQ3X6/7Y=
-golang.org/x/sys v0.18.0 h1:DBdB3niSjOA/O0blCZBqDefyWNYveAYMNF1Wum0DYQ4=
-golang.org/x/sys v0.18.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/sys v0.19.0 h1:q5f1RH2jigJ1MoAWp2KTp3gm5zAGFUTarQZ5U386+4o=
+golang.org/x/sys v0.19.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/text v0.14.0 h1:ScX5w1eTa3QqT8oi6+ziP7dTV1S2+ALU0bI+0zXKWiQ=
 golang.org/x/text v0.14.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU=
-gorm.io/gorm v1.25.8 h1:WAGEZ/aEcznN4D03laj8DKnehe1e9gYQAjW8xyPRdeo=
-gorm.io/gorm v1.25.8/go.mod h1:hbnx/Oo0ChWMn1BIhpy1oYozzpM15i4YPuHDmfYtwg8=
+gorm.io/gorm v1.25.9 h1:wct0gxZIELDk8+ZqF/MVnHLkA1rvYlBWUMv2EdsK1g8=
+gorm.io/gorm v1.25.9/go.mod h1:hbnx/Oo0ChWMn1BIhpy1oYozzpM15i4YPuHDmfYtwg8=

gormlite/test.sh

@@ -7,7 +7,7 @@ rm -rf gorm/ tests/
 go work use -r .
 go test
 
-git clone --branch v1.25.8 --filter=blob:none https://github.com/go-gorm/gorm.git
+git clone --branch v1.25.9 --filter=blob:none https://github.com/go-gorm/gorm.git
 mv gorm/tests tests
 rm -rf gorm/
 

internal/util/alloc.go

@@ -0,0 +1,81 @@
+//go:build unix
+
+package util
+
+import (
+	"math"
+
+	"github.com/tetratelabs/wazero/experimental"
+	"golang.org/x/sys/unix"
+)
+
+func mmappedAllocator(min, cap, max uint64) experimental.MemoryBuffer {
+	// Round up to the page size.
+	rnd := uint64(unix.Getpagesize() - 1)
+	max = (max + rnd) &^ rnd
+	cap = (cap + rnd) &^ rnd
+
+	if max > math.MaxInt {
+		// This ensures int(max) overflows to a negative value,
+		// and unix.Mmap returns EINVAL.
+		max = math.MaxUint64
+	}
+	// Reserve max bytes of address space, to ensure we won't need to move it.
+	// A protected, private, anonymous mapping should not commit memory.
+	b, err := unix.Mmap(-1, 0, int(max), unix.PROT_NONE, unix.MAP_PRIVATE|unix.MAP_ANON)
+	if err != nil {
+		panic(err)
+	}
+	// Commit the initial cap bytes of memory.
+	err = unix.Mprotect(b[:cap], unix.PROT_READ|unix.PROT_WRITE)
+	if err != nil {
+		unix.Munmap(b)
+		panic(err)
+	}
+	return &mmappedBuffer{
+		buf: b[:cap],
+		cur: min,
+	}
+}
+
+// The slice covers the entire mmapped memory:
+//   - len(buf) is the already committed memory,
+//   - cap(buf) is the reserved address space,
+//   - cur is the already requested size.
+type mmappedBuffer struct {
+	buf []byte
+	cur uint64
+}
+
+func (m *mmappedBuffer) Buffer() []byte {
+	// Limit capacity because bytes beyond len(m.buf)
+	// have not yet been committed.
+	return m.buf[:m.cur:len(m.buf)]
+}
+
+func (m *mmappedBuffer) Grow(size uint64) []byte {
+	if com := uint64(len(m.buf)); com < size {
+		// Round up to the page size.
+		rnd := uint64(unix.Getpagesize() - 1)
+		new := (size + rnd) &^ rnd
+
+		// Commit additional memory up to new bytes.
+		err := unix.Mprotect(m.buf[com:new], unix.PROT_READ|unix.PROT_WRITE)
+		if err != nil {
+			panic(err)
+		}
+
+		// Update commited memory.
+		m.buf = m.buf[:new]
+	}
+	m.cur = size
+	return m.Buffer()
+}
+
+func (m *mmappedBuffer) Free() {
+	err := unix.Munmap(m.buf[:cap(m.buf)])
+	if err != nil {
+		panic(err)
+	}
+	m.buf = nil
+}

internal/util/handle.go

@@ -3,21 +3,11 @@ package util
 import (
 	"context"
 	"io"
-
-	"github.com/tetratelabs/wazero/experimental"
 )
 
-type handleKey struct{}
 type handleState struct {
 	handles []any
-	empty   int
-}
-
-func NewContext(ctx context.Context) context.Context {
-	state := new(handleState)
-	ctx = experimental.WithCloseNotifier(ctx, state)
-	ctx = context.WithValue(ctx, handleKey{}, state)
-	return ctx
+	holes   int
 }
 
 func (s *handleState) CloseNotify(ctx context.Context, exitCode uint32) {
@@ -27,25 +17,25 @@ func (s *handleState) CloseNotify(ctx context.Context, exitCode uint32) {
 		}
 	}
 	s.handles = nil
-	s.empty = 0
+	s.holes = 0
 }
 
 func GetHandle(ctx context.Context, id uint32) any {
 	if id == 0 {
 		return nil
 	}
-	s := ctx.Value(handleKey{}).(*handleState)
+	s := ctx.Value(moduleKey{}).(*moduleState)
 	return s.handles[^id]
 }
 
 func DelHandle(ctx context.Context, id uint32) error {
 	if id == 0 {
 		return nil
 	}
-	s := ctx.Value(handleKey{}).(*handleState)
+	s := ctx.Value(moduleKey{}).(*moduleState)
 	a := s.handles[^id]
 	s.handles[^id] = nil
-	s.empty++
+	s.holes++
 	if c, ok := a.(io.Closer); ok {
 		return c.Close()
 	}
@@ -56,13 +46,13 @@ func AddHandle(ctx context.Context, a any) (id uint32) {
 	if a == nil {
 		panic(NilErr)
 	}
-	s := ctx.Value(handleKey{}).(*handleState)
+	s := ctx.Value(moduleKey{}).(*moduleState)
 
 	// Find an empty slot.
-	if s.empty > cap(s.handles)-len(s.handles) {
+	if s.holes > cap(s.handles)-len(s.handles) {
 		for id, h := range s.handles {
 			if h == nil {
-				s.empty--
+				s.holes--
 				s.handles[id] = a
 				return ^uint32(id)
 			}

internal/util/mmap.go

@@ -0,0 +1,105 @@
+//go:build (linux || darwin) && (amd64 || arm64) && !sqlite3_flock && !sqlite3_noshm && !sqlite3_nosys
+
+package util
+
+import (
+	"context"
+	"os"
+	"unsafe"
+
+	"github.com/tetratelabs/wazero/api"
+	"github.com/tetratelabs/wazero/experimental"
+	"golang.org/x/sys/unix"
+)
+
+type mmapState struct {
+	regions []*MappedRegion
+	enabled bool
+}
+
+func (s *mmapState) init(ctx context.Context, enabled bool) context.Context {
+	if s.enabled = enabled; enabled {
+		return experimental.WithMemoryAllocator(ctx, mmappedAllocator)
+	}
+	return ctx
+}
+
+func CanMap(ctx context.Context) bool {
+	s := ctx.Value(moduleKey{}).(*moduleState)
+	return s.mmapState.enabled
+}
+
+func (s *mmapState) new(ctx context.Context, mod api.Module, size uint32) *MappedRegion {
+	// Find unused region.
+	for _, r := range s.regions {
+		if !r.used && r.size == size {
+			return r
+		}
+	}
+
+	// Allocate page aligned memmory.
+	alloc := mod.ExportedFunction("aligned_alloc")
+	stack := [2]uint64{
+		uint64(unix.Getpagesize()),
+		uint64(size),
+	}
+	if err := alloc.CallWithStack(ctx, stack[:]); err != nil {
+		panic(err)
+	}
+	if stack[0] == 0 {
+		panic(OOMErr)
+	}
+
+	// Save the newly allocated region.
+	ptr := uint32(stack[0])
+	buf := View(mod, ptr, uint64(size))
+	addr := uintptr(unsafe.Pointer(&buf[0]))
+	s.regions = append(s.regions, &MappedRegion{
+		Ptr:  ptr,
+		addr: addr,
+		size: size,
+	})
+	return s.regions[len(s.regions)-1]
+}
+
+type MappedRegion struct {
+	addr uintptr
+	Ptr  uint32
+	size uint32
+	used bool
+}
+
+func MapRegion(ctx context.Context, mod api.Module, f *os.File, offset int64, size uint32) (*MappedRegion, error) {
+	s := ctx.Value(moduleKey{}).(*moduleState)
+	r := s.new(ctx, mod, size)
+	err := r.mmap(f, offset)
+	if err != nil {
+		return nil, err
+	}
+	return r, nil
+}
+
+func (r *MappedRegion) Unmap() error {
+	// We can't munmap the region, otherwise it could be remaped.
+	// Instead, convert it to a protected, private, anonymous mapping.
+	// If successful, it can be reused for a subsequent mmap.
+	_, err := mmap(r.addr, uintptr(r.size),
+		unix.PROT_NONE, unix.MAP_PRIVATE|unix.MAP_ANON|unix.MAP_FIXED,
+		-1, 0)
+	r.used = err != nil
+	return err
+}
+
+func (r *MappedRegion) mmap(f *os.File, offset int64) error {
+	_, err := mmap(r.addr, uintptr(r.size),
+		unix.PROT_READ|unix.PROT_WRITE, unix.MAP_SHARED|unix.MAP_FIXED,
+		int(f.Fd()), offset)
+	r.used = err == nil
+	return err
+}
+
+//go:linkname mmap syscall.mmap
+func mmap(addr, length uintptr, prot, flag, fd int, pos int64) (*byte, error)
+
+//go:linkname munmap syscall.munmap
+func munmap(addr, length uintptr) error

internal/util/mmap_other.go

@@ -0,0 +1,15 @@
+//go:build !(linux || darwin) || !(amd64 || arm64) || sqlite3_flock || sqlite3_noshm || sqlite3_nosys
+
+package util
+
+import "context"
+
+type mmapState struct{}
+
+func (s *mmapState) init(ctx context.Context, _ bool) context.Context {
+	return ctx
+}
+
+func CanMap(ctx context.Context) bool {
+	return false
+}