wait_for, fallback to read for non mmapable files (#82064)

* also handle oserror, added debug jic

changelogs/fragments/wait_for_mmap.yml

@@ -0,0 +1,2 @@
+bugfixes:
+  - wait_for should not handle 'non mmapable files' again.

lib/ansible/modules/wait_for.py

@@ -237,7 +237,7 @@ import traceback
 
 from ansible.module_utils.basic import AnsibleModule, missing_required_lib
 from ansible.module_utils.common.sys_info import get_platform_subclass
-from ansible.module_utils.common.text.converters import to_bytes
+from ansible.module_utils.common.text.converters import to_bytes, to_native
 from ansible.module_utils.compat.datetime import utcnow
 
 
@@ -584,17 +584,30 @@ def main():
                     if not b_compiled_search_re:
                         # nope, succeed!
                         break
+
                     try:
                         with open(b_path, 'rb') as f:
-                            with contextlib.closing(mmap.mmap(f.fileno(), 0, access=mmap.ACCESS_READ)) as mm:
-                                search = b_compiled_search_re.search(mm)
+                            try:
+                                with contextlib.closing(mmap.mmap(f.fileno(), 0, access=mmap.ACCESS_READ)) as mm:
+                                    search = b_compiled_search_re.search(mm)
+                                    if search:
+                                        if search.groupdict():
+                                            match_groupdict = search.groupdict()
+                                        if search.groups():
+                                            match_groups = search.groups()
+                                        break
+                            except (ValueError, OSError) as e:
+                                module.debug('wait_for failed to use mmap on "%s": %s. Falling back to file read().' % (path, to_native(e)))
+                                # cannot mmap this file, try normal read
+                                search = re.search(b_compiled_search_re, f.read())
                                 if search:
                                     if search.groupdict():
                                         match_groupdict = search.groupdict()
                                     if search.groups():
                                         match_groups = search.groups()
-
                                     break
+                            except Exception as e:
+                                module.warn('wait_for failed on "%s", unexpected exception(%s): %s.).' % (path, to_native(e.__class__), to_native(e)))
                     except IOError:
                         pass
             elif port:

test/integration/targets/wait_for/tasks/main.yml

@@ -91,7 +91,7 @@
   wait_for:
     path: "{{remote_tmp_dir}}/wait_for_keyword"
     search_regex: completed (?P<foo>\w+) ([0-9]+)
-    timeout: 5
+    timeout: 25
   register: waitfor
 
 - name: verify test wait for keyword in file with match groups
@@ -114,6 +114,13 @@
     path: "{{remote_tmp_dir}}/utf16.txt"
     search_regex: completed
 
+- name: test non mmapable file
+  wait_for:
+    path: "/sys/class/net/lo/carrier"
+    search_regex: "1"
+    timeout: 30
+  when: ansible_os_family not in ['FreeBSD', 'Darwin']
+
 - name: test wait for port timeout
   wait_for:
     port: 12121