dlfcn: dlerror requires a global lock anyway

2 files changed, 17 insertions, 14 deletions

diff --git a/dl/dlfcn.go b/dl/dlfcn.go
index eb40794..e240540 100644
--- a/dl/dlfcn.go
+++ b/dl/dlfcn.go
@@ -58,33 +58,36 @@ const (
 type Handle struct {
 	c unsafe.Pointer
 	o int
-	l sync.RWMutex
 }
 
+var dllock sync.Mutex
+
 // Open a shared object file, returning a Handle to it, or an error.
 // If name is an empty string, then the returned handle is the global
 // symbol table for the current process; if the name contains a slash,
 // then it is interpretted as a pathname; otherwise, it is
 // interpretted in an implementation-defined manner.
-func Open(name string, flags Flag) (*Handle, error) {
+func Open(name string, flags Flag) (Handle, error) {
 	nameC := C.CString(name)
 	defer C.free(unsafe.Pointer(nameC))
 	if name == "" {
 		nameC = nil
 	}
 
+	dllock.Lock()
+	defer dllock.Unlock()
 	dlerror()
 	ptr := C.dlopen(nameC, C.int(flags))
 	if ptr == nil {
-		return &Handle{}, dlerror()
+		return Handle{}, dlerror()
 	}
-	return &Handle{c: ptr, o: 1}, nil
+	return Handle{c: ptr, o: 1}, nil
 }
 
 // Look up a symbol, and return a pointer to it.
-func (h *Handle) Sym(symbol string) (unsafe.Pointer, error) {
-	h.l.RLock()
-	defer h.l.RUnlock()
+func (h Handle) Sym(symbol string) (unsafe.Pointer, error) {
+	dllock.Lock()
+	defer dllock.Unlock()
 
 	if h.o == 0 {
 		return nil, HandleClosedError
@@ -104,9 +107,9 @@ func (h *Handle) Sym(symbol string) (unsafe.Pointer, error) {
 // Close this handle on a shared object; decrementint the reference
 // count; if the reference count drops below 0, then the object is
 // unloaded.
-func (h *Handle) Close() error {
-	h.l.Lock()
-	defer h.l.Unlock()
+func (h Handle) Close() error {
+	dllock.Lock()
+	defer dllock.Unlock()
 
 	if h.o == 0 {
 		return HandleClosedError
diff --git a/dl/dlsym_reserved.go b/dl/dlsym_reserved.go
index cfa0dca..081e012 100644
--- a/dl/dlsym_reserved.go
+++ b/dl/dlsym_reserved.go
@@ -44,7 +44,7 @@ var (
 	// the executable and its dependencies, as well as symbols in
 	// shared objects that were dynamically loaded with the
 	// RTLD_GLOBAL flag.
-	RTLD_DEFAULT *Handle
+	RTLD_DEFAULT Handle
 
 	// This Handle represents the shared object search order after
 	// the current object.  This allows one to provide a wrapper
@@ -54,10 +54,10 @@ var (
 	// "real" function provided in another shared object (or for
 	// that matter, the "next" definition of the function in cases
 	// where there are multiple layers of preloading).
-	RTLD_NEXT *Handle
+	RTLD_NEXT Handle
 )
 
 func init() {
-	RTLD_DEFAULT = &Handle{c: unsafe.Pointer(uintptr(C.rtld_default)), o: 2}
-	RTLD_DEFAULT = &Handle{c: unsafe.Pointer(uintptr(C.rtld_next)), o: 2}
+	RTLD_DEFAULT = Handle{c: unsafe.Pointer(uintptr(C.rtld_default)), o: 2}
+	RTLD_DEFAULT = Handle{c: unsafe.Pointer(uintptr(C.rtld_next)), o: 2}
 }