1 files changed, 68 insertions, 0 deletions
diff --git a/src/pkg/syscall/syscall_unix.go b/src/pkg/syscall/syscall_unix.go
index a77e40bc6..20c8a135f 100644
--- a/src/pkg/syscall/syscall_unix.go
+++ b/src/pkg/syscall/syscall_unix.go
@@ -4,12 +4,20 @@
 
 package syscall
 
+import (
+	"sync"
+	"unsafe"
+)
+
+
 var (
 	Stdin  = 0
 	Stdout = 1
 	Stderr = 2
 )
 
+const darwinAMD64 = OS == "darwin" && ARCH == "amd64"
+
 func Syscall(trap, a1, a2, a3 uintptr) (r1, r2, err uintptr)
 func Syscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2, err uintptr)
 func RawSyscall(trap, a1, a2, a3 uintptr) (r1, r2, err uintptr)
@@ -21,3 +29,63 @@ func Errstr(errno int) string {
 	}
 	return errors[errno]
 }
+
+// Mmap manager, for use by operating system-specific implementations.
+
+type mmapper struct {
+	sync.Mutex
+	active map[*byte][]byte // active mappings; key is last byte in mapping
+	mmap   func(addr, length uintptr, prot, flags, fd int, offset int64) (uintptr, int)
+	munmap func(addr uintptr, length uintptr) int
+}
+
+func (m *mmapper) Mmap(fd int, offset int64, length int, prot int, flags int) (data []byte, errno int) {
+	if length <= 0 {
+		return nil, EINVAL
+	}
+
+	// Map the requested memory.
+	addr, errno := m.mmap(0, uintptr(length), prot, flags, fd, offset)
+	if errno != 0 {
+		return nil, errno
+	}
+
+	// Slice memory layout
+	var sl = struct {
+		addr uintptr
+		len  int
+		cap  int
+	}{addr, length, length}
+
+	// Use unsafe to turn sl into a []byte.
+	b := *(*[]byte)(unsafe.Pointer(&sl))
+
+	// Register mapping in m and return it.
+	p := &b[cap(b)-1]
+	m.Lock()
+	defer m.Unlock()
+	m.active[p] = b
+	return b, 0
+}
+
+func (m *mmapper) Munmap(data []byte) (errno int) {
+	if len(data) == 0 || len(data) != cap(data) {
+		return EINVAL
+	}
+
+	// Find the base of the mapping.
+	p := &data[cap(data)-1]
+	m.Lock()
+	defer m.Unlock()
+	b := m.active[p]
+	if b == nil || &b[0] != &data[0] {
+		return EINVAL
+	}
+
+	// Unmap the memory and update m.
+	if errno := m.munmap(uintptr(unsafe.Pointer(&b[0])), uintptr(len(b))); errno != 0 {
+		return errno
+	}
+	m.active[p] = nil, false
+	return 0
+}