solaris: fix issues with mmap, munmap, madvise and flock

bolt_unix.go

@@ -1,4 +1,4 @@
-// +build !windows,!plan9
+// +build !windows,!plan9,!solaris
 
 package bolt
 

bolt_unix_solaris.go

@@ -0,0 +1,101 @@
+
+package bolt
+
+import (
+	"fmt"
+	"os"
+	"syscall"
+	"time"
+	"unsafe"
+	"golang.org/x/sys/unix"
+)
+
+// flock acquires an advisory lock on a file descriptor.
+func flock(f *os.File, exclusive bool, timeout time.Duration) error {
+	var t time.Time
+	for {
+		// If we're beyond our timeout then return an error.
+		// This can only occur after we've attempted a flock once.
+		if t.IsZero() {
+			t = time.Now()
+		} else if timeout > 0 && time.Since(t) > timeout {
+			return ErrTimeout
+		}
+		var lock syscall.Flock_t
+		lock.Start = 0
+		lock.Len = 0
+		lock.Pid = 0
+		lock.Whence = 0
+		lock.Pid = 0
+		if exclusive {
+			lock.Type = syscall.F_WRLCK
+		} else {
+			lock.Type = syscall.F_RDLCK
+		}
+		err := syscall.FcntlFlock(f.Fd(), syscall.F_SETLK, &lock)
+		if err == nil {
+			return nil
+		} else if err != syscall.EAGAIN {
+			return err
+		}
+
+		// Wait for a bit and try again.
+		time.Sleep(50 * time.Millisecond)
+	}
+}
+
+// funlock releases an advisory lock on a file descriptor.
+func funlock(f *os.File) error {
+	var lock syscall.Flock_t
+	lock.Start = 0
+	lock.Len = 0
+	lock.Type = syscall.F_UNLCK
+	lock.Whence = 0
+	return syscall.FcntlFlock(uintptr(f.Fd()), syscall.F_SETLK, &lock)
+}
+
+// mmap memory maps a DB's data file.
+func mmap(db *DB, sz int) error {
+	// Truncate and fsync to ensure file size metadata is flushed.
+	// https://github.com/boltdb/bolt/issues/284
+	if !db.NoGrowSync && !db.readOnly {
+		if err := db.file.Truncate(int64(sz)); err != nil {
+			return fmt.Errorf("file resize error: %s", err)
+		}
+		if err := db.file.Sync(); err != nil {
+			return fmt.Errorf("file sync error: %s", err)
+		}
+	}
+
+	// Map the data file to memory.
+	b, err := unix.Mmap(int(db.file.Fd()), 0, sz, syscall.PROT_READ, syscall.MAP_SHARED)
+	if err != nil {
+		return err
+	}
+
+	// Advise the kernel that the mmap is accessed randomly.
+	if err := unix.Madvise(b, syscall.MADV_RANDOM); err != nil {
+		return fmt.Errorf("madvise: %s", err)
+	}
+
+	// Save the original byte slice and convert to a byte array pointer.
+	db.dataref = b
+	db.data = (*[maxMapSize]byte)(unsafe.Pointer(&b[0]))
+	db.datasz = sz
+	return nil
+}
+
+// munmap unmaps a DB's data file from memory.
+func munmap(db *DB) error {
+	// Ignore the unmap if we have no mapped data.
+	if db.dataref == nil {
+		return nil
+	}
+
+	// Unmap using the original byte slice.
+	err := unix.Munmap(db.dataref)
+	db.dataref = nil
+	db.data = nil
+	db.datasz = 0
+	return err
+}

db_test.go

@@ -42,6 +42,9 @@ func TestOpen_Timeout(t *testing.T) {
 	if runtime.GOOS == "windows" {
 		t.Skip("timeout not supported on windows")
 	}
+	if runtime.GOOS == "solaris" {
+		t.Skip("solaris fcntl locks don't support intra-process locking")
+	}
 
 	path := tempfile()
 	defer os.Remove(path)
@@ -66,6 +69,9 @@ func TestOpen_Wait(t *testing.T) {
 	if runtime.GOOS == "windows" {
 		t.Skip("timeout not supported on windows")
 	}
+	if runtime.GOOS == "solaris" {
+		t.Skip("solaris fcntl locks don't support intra-process locking")
+	}
 
 	path := tempfile()
 	defer os.Remove(path)
@@ -228,6 +234,10 @@ func TestDB_Open_FileTooSmall(t *testing.T) {
 // and that a database can not be opened in read-write mode and in read-only
 // mode at the same time.
 func TestOpen_ReadOnly(t *testing.T) {
+	if runtime.GOOS == "solaris" {
+		t.Skip("solaris fcntl locks don't support intra-process locking")
+	}
+
 	bucket, key, value := []byte(`bucket`), []byte(`key`), []byte(`value`)
 
 	path := tempfile()