fix: set write permissions for group and other

Fixes #1403.

internal/proxy/proxy.go

@@ -619,13 +619,20 @@ func newSocketMount(ctx context.Context, conf *Config, pc *portConfig, inst Inst
 			}
 			address = UnixAddress(address, ".s.PGSQL.5432")
 		}
+
 	}
 
 	lc := net.ListenConfig{KeepAlive: 30 * time.Second}
 	ln, err := lc.Listen(ctx, network, address)
 	if err != nil {
 		return nil, err
 	}
+	// Change file permisions to allow access for user, group, and other.
+	if network == "unix" {
+		// Best effort. If this call fails, group and other won't have write
+		// access.
+		_ = os.Chmod(address, 0777)
+	}
 	opts := conf.DialOptions(inst)
 	m := &socketMount{inst: inst.Name, dialOpts: opts, listener: ln}
 	return m, nil

internal/proxy/proxy_test.go

@@ -283,6 +283,14 @@ func TestClientInitialization(t *testing.T) {
 			}
 
 			for _, addr := range tc.wantUnixAddrs {
+				fi, err := os.Stat(addr)
+				if err != nil {
+					t.Fatalf("os.Stat(%v): %v", addr, err)
+				}
+				if fm := fi.Mode(); fm != 0777|os.ModeSocket {
+					t.Fatalf("file mode: want = %v, got = %v", 0777|os.ModeSocket, fm)
+				}
+
 				conn, err := net.Dial("unix", addr)
 				if err != nil {
 					t.Fatalf("want error = nil, got = %v", err)