Add BusyBox support to group module (#54689)

* Add BusyBox support to group module

* Use bytes when reading/writing to file

lib/ansible/modules/system/group.py

@@ -56,6 +56,7 @@ options:
     non_unique:
         description:
             - This option allows to change the group ID to a non-unique value. Requires C(gid).
+            - Not supported on macOS or BusyBox distributions.
         type: bool
         default: no
         version_added: "2.8"
@@ -75,6 +76,7 @@ EXAMPLES = '''
 
 import grp
 
+from ansible.module_utils._text import to_bytes
 from ansible.module_utils.basic import AnsibleModule, load_platform_subclass
 
 
@@ -463,6 +465,63 @@ class NetBsdGroup(Group):
 
 # ===========================================
 
+
+class BusyBoxGroup(Group):
+    """
+    BusyBox group manipulation class for systems that have addgroup and delgroup.
+
+    It overrides the following methods:
+        - group_add()
+        - group_del()
+        - group_mod()
+    """
+
+    def group_add(self, **kwargs):
+        cmd = [self.module.get_bin_path('addgroup', True)]
+        if self.gid is not None:
+            cmd.extend(['-g', str(self.gid)])
+
+        if self.system:
+            cmd.append('-S')
+
+        cmd.append(self.name)
+
+        return self.execute_command(cmd)
+
+    def group_del(self):
+        cmd = [self.module.get_bin_path('delgroup', True), self.name]
+        return self.execute_command(cmd)
+
+    def group_mod(self, **kwargs):
+        # Since there is no groupmod command, modify /etc/group directly
+        info = self.group_info()
+        if self.gid is not None and self.gid != info[2]:
+            with open('/etc/group', 'rb') as f:
+                b_groups = f.read()
+
+            b_name = to_bytes(self.name)
+            b_current_group_string = b'%s:x:%d:' % (b_name, info[2])
+            b_new_group_string = b'%s:x:%d:' % (b_name, self.gid)
+
+            if b':%d:' % self.gid in b_groups:
+                self.module.fail_json(msg="gid '{gid}' in use".format(gid=self.gid))
+
+            if self.module.check_mode:
+                return 0, '', ''
+            b_new_groups = b_groups.replace(b_current_group_string, b_new_group_string)
+            with open('/etc/group', 'wb') as f:
+                f.write(b_new_groups)
+            return 0, '', ''
+
+        return None, '', ''
+
+
+class AlpineGroup(BusyBoxGroup):
+
+    platform = 'Linux'
+    distribution = 'Alpine'
+
+
 def main():
     module = AnsibleModule(
         argument_spec=dict(