Optimize wrapper to scripts with long shebangs

slapos/recipe/cmmi/__init__.py

@@ -409,16 +409,18 @@ class Recipe(object):
                 continue
             for f in os.listdir(dir_abspath):
                 f_abspath = os.path.join(dir_abspath, f)
-                if not os.path.isfile(f_abspath):
+                st_mode = os.stat(f_abspath).st_mode
+                if not stat.S_ISREG(st_mode):
                     continue
-                header = file(f_abspath).readline(128)
-                m = re.match('^#! ?(/.*)', header)
-                if not m or len(header) < 128:
-                    continue
-                shebang_abspath = f_abspath + '.shebang'
-                os.rename(f_abspath, shebang_abspath)
-                file(f_abspath, 'w').write('''#!/bin/sh
-shebang=$(head -1 "$0.shebang")
-exec ${shebang#\#!} "$0.shebang" "$@"
+                with open(f_abspath) as f:
+                    header = f.readline(128)
+                if header.startswith('#!') and header[-1] != '\n':
+                    os.rename(f_abspath, f_abspath + '.shebang')
+                    with open(f_abspath, 'w') as f:
+                        os.fchmod(f.fileno(), stat.S_IMODE(st_mode))
+                        f.write('''#!/bin/sh -e
+read -r EXE ARG < "$0.shebang"
+EXE=${EXE#\\#!}
+[ "$EXE" ] || read -r _ EXE ARG < "$0.shebang"
+exec $EXE ${ARG:+"$ARG"} "$0.shebang" "$@"
 ''')
-                os.chmod(f_abspath, stat.S_IMODE(os.stat(shebang_abspath).st_mode))