1 files changed, 41 insertions, 0 deletions
diff --git a/bolt_linux.go b/bolt_linux.go
index 4351db5..761a83e 100644
--- a/bolt_linux.go
+++ b/bolt_linux.go
@@ -3,10 +3,51 @@ package bolt
 import (
 	"os"
 	"syscall"
+	"unsafe"
 )
 
 var odirect = syscall.O_DIRECT
 
+// fdatasync flushes written data to a file descriptor.
 func fdatasync(f *os.File) error {
 	return syscall.Fdatasync(int(f.Fd()))
 }
+
+// flock acquires an advisory lock on a file descriptor.
+func flock(f *os.File) error {
+	return syscall.Flock(int(f.Fd()), syscall.LOCK_EX)
+}
+
+// funlock releases an advisory lock on a file descriptor.
+func funlock(f *os.File) error {
+	return syscall.Flock(int(f.Fd()), syscall.LOCK_UN)
+}
+
+// mmap memory maps a DB's data file.
+func mmap(db *DB, sz int) error {
+	b, err := syscall.Mmap(int(db.file.Fd()), 0, sz, syscall.PROT_READ, syscall.MAP_SHARED)
+	if err != nil {
+		return 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 := syscall.Munmap(db.dataref)
+	db.dataref = nil
+	db.data = nil
+	db.datasz = 0
+	return err
+}