Fix unsafe pointer conversions caught by Go 1.14 checkptr

Port of etcd-io/bbolt@543c40a
Now tests don't crush with -race flag
Also found new race, reported to etcd/bolt: etcd-io#213

bolt_386.go

@@ -5,6 +5,3 @@ const maxMapSize = 0x7FFFFFFF // 2GB
 
 // maxAllocSize is the size used when creating array pointers.
 const maxAllocSize = 0xFFFFFFF
-
-// Are unaligned load/stores broken on this arch?
-var brokenUnaligned = false

bolt_amd64.go

@@ -5,6 +5,3 @@ const maxMapSize = 0xFFFFFFFFFFFF // 256TB
 
 // maxAllocSize is the size used when creating array pointers.
 const maxAllocSize = 0x7FFFFFFF
-
-// Are unaligned load/stores broken on this arch?
-var brokenUnaligned = false

bolt_arm.go

@@ -1,28 +1,7 @@
 package bolt
 
-import "unsafe"
-
 // maxMapSize represents the largest mmap size supported by Bolt.
 const maxMapSize = 0x7FFFFFFF // 2GB
 
 // maxAllocSize is the size used when creating array pointers.
 const maxAllocSize = 0xFFFFFFF
-
-// Are unaligned load/stores broken on this arch?
-var brokenUnaligned bool
-
-func init() {
-	// Simple check to see whether this arch handles unaligned load/stores
-	// correctly.
-
-	// ARM9 and older devices require load/stores to be from/to aligned
-	// addresses. If not, the lower 2 bits are cleared and that address is
-	// read in a jumbled up order.
-
-	// See http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.faqs/ka15414.html
-
-	raw := [6]byte{0xfe, 0xef, 0x11, 0x22, 0x22, 0x11}
-	val := *(*uint32)(unsafe.Pointer(uintptr(unsafe.Pointer(&raw)) + 2))
-
-	brokenUnaligned = val != 0x11222211
-}

bolt_arm64.go

@@ -7,6 +7,3 @@ const maxMapSize = 0xFFFFFFFFFFFF // 256TB
 
 // maxAllocSize is the size used when creating array pointers.
 const maxAllocSize = 0x7FFFFFFF
-
-// Are unaligned load/stores broken on this arch?
-var brokenUnaligned = false

bolt_ppc64.go

@@ -7,6 +7,3 @@ const maxMapSize = 0xFFFFFFFFFFFF // 256TB
 
 // maxAllocSize is the size used when creating array pointers.
 const maxAllocSize = 0x7FFFFFFF
-
-// Are unaligned load/stores broken on this arch?
-var brokenUnaligned = false

bolt_ppc64le.go

@@ -7,6 +7,3 @@ const maxMapSize = 0xFFFFFFFFFFFF // 256TB
 
 // maxAllocSize is the size used when creating array pointers.
 const maxAllocSize = 0x7FFFFFFF
-
-// Are unaligned load/stores broken on this arch?
-var brokenUnaligned = false

bolt_s390x.go

@@ -7,6 +7,3 @@ const maxMapSize = 0xFFFFFFFFFFFF // 256TB
 
 // maxAllocSize is the size used when creating array pointers.
 const maxAllocSize = 0x7FFFFFFF
-
-// Are unaligned load/stores broken on this arch?
-var brokenUnaligned = false

bucket.go

@@ -554,24 +554,24 @@ func (b *Bucket) Stats() BucketStats {
 
 			if p.count != 0 {
 				// If page has any elements, add all element headers.
-				used += leafPageElementSize * int(p.count-1)
+				used += leafPageElementSize * uintptr(p.count-1)
 
 				// Add all element key, value sizes.
 				// The computation takes advantage of the fact that the position
 				// of the last element's key/value equals to the total of the sizes
 				// of all previous elements' keys and values.
 				// It also includes the last element's header.
 				lastElement := p.leafPageElement(p.count - 1)
-				used += int(lastElement.pos + lastElement.ksize + lastElement.vsize)
+				used += uintptr(lastElement.pos + lastElement.ksize + lastElement.vsize)
 			}
 
 			if b.root == 0 {
 				// For inlined bucket just update the inline stats
-				s.InlineBucketInuse += used
+				s.InlineBucketInuse += int(used)
 			} else {
 				// For non-inlined bucket update all the leaf stats
 				s.LeafPageN++
-				s.LeafInuse += used
+				s.LeafInuse += int(used)
 				s.LeafOverflowN += int(p.overflow)
 
 				// Collect stats from sub-buckets.
@@ -588,31 +588,31 @@ func (b *Bucket) Stats() BucketStats {
 			}
 		} else if (p.flags & branchPageFlag) != 0 {
 			s.BranchPageN++
-			var used int
+			var used uintptr
 			if b.enum {
 				lastElement := p.branchPageElementX(p.count - 1)
 
 				// used totals the used bytes for the page
 				// Add header and all element headers.
-				used = pageHeaderSize + (branchPageElementSizeX * int(p.count-1))
+				used = pageHeaderSize + (branchPageElementSizeX * uintptr(p.count-1))
 
 				// Add size of all keys and values.
 				// Again, use the fact that last element's position equals to
 				// the total of key, value sizes of all previous elements.
-				used += int(lastElement.pos + lastElement.ksize)
+				used += uintptr(lastElement.pos + lastElement.ksize)
 			} else {
 				lastElement := p.branchPageElement(p.count - 1)
 
 				// used totals the used bytes for the page
 				// Add header and all element headers.
-				used = pageHeaderSize + (branchPageElementSize * int(p.count-1))
+				used = pageHeaderSize + (branchPageElementSize * uintptr(p.count-1))
 
 				// Add size of all keys and values.
 				// Again, use the fact that last element's position equals to
 				// the total of key, value sizes of all previous elements.
-				used += int(lastElement.pos + lastElement.ksize)
+				used += uintptr(lastElement.pos + lastElement.ksize)
 			}
-			s.BranchInuse += used
+			s.BranchInuse += int(used)
 			s.BranchOverflowN += int(p.overflow)
 		}
 
@@ -758,7 +758,7 @@ func (b *Bucket) inlineable() bool {
 	var size = pageHeaderSize
 	var prefix []byte
 	for i, inode := range n.inodes {
-		size += leafPageElementSize + len(inode.key) + len(inode.value)
+		size += leafPageElementSize + uintptr(len(inode.key)) + uintptr(len(inode.value))
 		if !b.tx.db.KeysPrefixCompressionDisable {
 			if prefix == nil {
 				prefix = inode.key
@@ -775,7 +775,7 @@ func (b *Bucket) inlineable() bool {
 		}
 		if inode.flags&bucketLeafFlag != 0 {
 			return false
-		} else if size-len(prefix)*i > b.maxInlineBucketSize() {
+		} else if size-uintptr(len(prefix)*i) > b.maxInlineBucketSize() {
 			return false
 		}
 	}
@@ -784,8 +784,8 @@ func (b *Bucket) inlineable() bool {
 }
 
 // Returns the maximum total size of a bucket to make it a candidate for inlining.
-func (b *Bucket) maxInlineBucketSize() int {
-	return b.tx.db.pageSize / 4
+func (b *Bucket) maxInlineBucketSize() uintptr {
+	return uintptr(b.tx.db.pageSize / 4)
 }
 
 // write allocates and writes a bucket to a byte slice.

freelist.go

@@ -2,6 +2,7 @@ package bolt
 
 import (
 	"fmt"
+	"reflect"
 	"sort"
 	"unsafe"
 )
@@ -29,7 +30,7 @@ func (f *freelist) size() int {
 		// The first element will be used to store the count. See freelist.write.
 		n++
 	}
-	return pageHeaderSize + (int(unsafe.Sizeof(pgid(0))) * n)
+	return int(pageHeaderSize) + (int(unsafe.Sizeof(pgid(0))) * n)
 }
 
 // count returns count of pages on the freelist
@@ -51,6 +52,23 @@ func (f *freelist) pending_count() int {
 	return count
 }
 
+// copyallunsafe copies a list of all free ids and all pending ids in one sorted list.
+// f.count returns the minimum length required for dst.
+func (f *freelist) copyallunsafe(dstptr unsafe.Pointer) { // dstptr is []pgid data pointer
+	m := make(pgids, 0, f.pending_count())
+	for _, list := range f.pending {
+		m = append(m, list...)
+	}
+	sort.Sort(m)
+	sz := len(f.ids) + len(m)
+	dst := *(*[]pgid)(unsafe.Pointer(&reflect.SliceHeader{
+		Data: uintptr(dstptr),
+		Len:  sz,
+		Cap:  sz,
+	}))
+	mergepgids(dst, f.ids, m)
+}
+
 // copyall copies into dst a list of all free ids and all pending ids in one sorted list.
 // f.count returns the minimum length required for dst.
 func (f *freelist) copyall(dst []pgid) {
@@ -163,17 +181,21 @@ func (f *freelist) freed(pgid pgid) bool {
 func (f *freelist) read(p *page) {
 	// If the page.count is at the max uint16 value (64k) then it's considered
 	// an overflow and the size of the freelist is stored as the first element.
-	idx, count := 0, int(p.count)
+	var idx, count uintptr = 0, uintptr(p.count)
 	if count == 0xFFFF {
 		idx = 1
-		count = int(((*[maxAllocSize]pgid)(unsafe.Pointer(&p.ptr)))[0])
+		count = uintptr(*(*pgid)(unsafe.Pointer(uintptr(unsafe.Pointer(p)) + pageHeaderSize)))
 	}
 
 	// Copy the list of page ids from the freelist.
 	if count == 0 {
 		f.ids = nil
 	} else {
-		ids := ((*[maxAllocSize]pgid)(unsafe.Pointer(&p.ptr)))[idx:count]
+		ids := *(*[]pgid)(unsafe.Pointer(&reflect.SliceHeader{
+			Data: uintptr(unsafe.Pointer(p)) + pageHeaderSize + idx*unsafe.Sizeof(pgid(0)),
+			Len:  int(count),
+			Cap:  int(count),
+		}))
 		f.ids = make([]pgid, len(ids))
 		copy(f.ids, ids)
 
@@ -201,11 +223,11 @@ func (f *freelist) write(p *page) error {
 		p.count = uint16(lenids)
 	} else if lenids < 0xFFFF {
 		p.count = uint16(lenids)
-		f.copyall(((*[maxAllocSize]pgid)(unsafe.Pointer(&p.ptr)))[:])
+		f.copyallunsafe(unsafe.Pointer(uintptr(unsafe.Pointer(p)) + pageHeaderSize))
 	} else {
 		p.count = 0xFFFF
-		((*[maxAllocSize]pgid)(unsafe.Pointer(&p.ptr)))[0] = pgid(lenids)
-		f.copyall(((*[maxAllocSize]pgid)(unsafe.Pointer(&p.ptr)))[1:])
+		*(*pgid)(unsafe.Pointer(uintptr(unsafe.Pointer(p)) + pageHeaderSize)) = pgid(lenids)
+		f.copyallunsafe(unsafe.Pointer(uintptr(unsafe.Pointer(p)) + pageHeaderSize + unsafe.Sizeof(pgid(0))))
 	}
 
 	return nil

freelist_test.go

@@ -95,7 +95,7 @@ func TestFreelist_read(t *testing.T) {
 	page.count = 2
 
 	// Insert 2 page ids.
-	ids := (*[3]pgid)(unsafe.Pointer(&page.ptr))
+	ids := (*[3]pgid)(unsafe.Pointer(uintptr(unsafe.Pointer(page)) + pageHeaderSize))
 	ids[0] = 23
 	ids[1] = 50
 

go.sum

@@ -1,4 +1,2 @@
 golang.org/x/sys v0.0.0-20200202164722-d101bd2416d5 h1:LfCXLvNmTYH9kEmVgqbnsWfruoXZIrh4YBgqVHtDvw0=
-golang.org/x/sys v0.0.0-20200202164722-d101bd2416d5/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20200331124033-c3d80250170d h1:nc5K6ox/4lTFbMVSL9WRR81ixkcwXThoiF6yf+R9scA=
-golang.org/x/sys v0.0.0-20200331124033-c3d80250170d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20200202164722-d101bd2416d5/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=