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fixes issue #13981: unsafe_writes block appeared too late in the atom… (#17405)

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* fixes issue #13981: unsafe_writes block appeared too late in the atomic_move
workflow. This led to errno.EBUSY to not be managed in the context of
issue #!#981

* Reduce changes to fix #13981

* Abstract the unsafe_writes fallback into a helper method.
Explicitly try/except os.rename part of the code and call this helper method.
If the code fails in shutil.copy2 or shutil.move this should not be related to issue #13981
since they write to b_tmp_dest_name.
(as suggested by @abadger)

* Check if unsafe_writes in the caller, not in _unsafe_writes.
That way the function call reads as "Do an unsafe write"
and not as "I think we should do an unsafe_write.
This commit is contained in:
Pascal Grange 2016-09-22 17:31:35 +02:00 committed by Brian Coca
parent 839f908a14
commit 8b08a28c89
1 changed files with 31 additions and 23 deletions
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54
lib/ansible/module_utils/basic.py
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@ -1941,7 +1941,7 @@ class AnsibleModule(object):
os.rename(b_src, b_dest)
except (IOError, OSError):
e = get_exception()
if e.errno not in [errno.EPERM, errno.EXDEV, errno.EACCES, errno.ETXTBSY]:
if e.errno not in [errno.EPERM, errno.EXDEV, errno.EACCES, errno.ETXTBSY, errno.EBUSY]:
# only try workarounds for errno 18 (cross device), 1 (not permitted), 13 (permission denied)
# and 26 (text file busy) which happens on vagrant synced folders and other 'exotic' non posix file systems
self.fail_json(msg='Could not replace file: %s to %s: %s' % (src, dest, e))
@ -1983,29 +1983,15 @@ class AnsibleModule(object):
e = get_exception()
if e.errno != errno.EPERM:
raise
os.rename(b_tmp_dest_name, b_dest)
try:
os.rename(b_tmp_dest_name, b_dest)
except (shutil.Error, OSError, IOError):
if unsafe_writes:
self._unsafe_writes(b_tmp_dest_name, b_dest, get_exception())
else:
self.fail_json(msg='Could not replace file: %s to %s: %s' % (src, dest, exception))
except (shutil.Error, OSError, IOError):
e = get_exception()
# sadly there are some situations where we cannot ensure atomicity, but only if
# the user insists and we get the appropriate error we update the file unsafely
if unsafe_writes and e.errno == errno.EBUSY:
#TODO: issue warning that this is an unsafe operation, but doing it cause user insists
try:
try:
out_dest = open(b_dest, 'wb')
in_src = open(b_src, 'rb')
shutil.copyfileobj(in_src, out_dest)
finally: # assuring closed files in 2.4 compatible way
if out_dest:
out_dest.close()
if in_src:
in_src.close()
except (shutil.Error, OSError, IOError):
e = get_exception()
self.fail_json(msg='Could not write data to file (%s) from (%s): %s' % (dest, src, e))
else:
self.fail_json(msg='Could not replace file: %s to %s: %s' % (src, dest, e))
self.fail_json(msg='Could not replace file: %s to %s: %s' % (src, dest, exception))
finally:
self.cleanup(b_tmp_dest_name)
@ -2022,6 +2008,28 @@ class AnsibleModule(object):
# rename might not preserve context
self.set_context_if_different(dest, context, False)
def _unsafe_writes(self, src, dest, exception):
# sadly there are some situations where we cannot ensure atomicity, but only if
# the user insists and we get the appropriate error we update the file unsafely
if exception.errno == errno.EBUSY:
#TODO: issue warning that this is an unsafe operation, but doing it cause user insists
try:
try:
out_dest = open(dest, 'wb')
in_src = open(src, 'rb')
shutil.copyfileobj(in_src, out_dest)
finally: # assuring closed files in 2.4 compatible way
if out_dest:
out_dest.close()
if in_src:
in_src.close()
except (shutil.Error, OSError, IOError):
e = get_exception()
self.fail_json(msg='Could not write data to file (%s) from (%s): %s' % (dest, src, e))
else:
self.fail_json(msg='Could not replace file: %s to %s: %s' % (src, dest, exception))
def run_command(self, args, check_rc=False, close_fds=True, executable=None, data=None, binary_data=False, path_prefix=None, cwd=None, use_unsafe_shell=False, prompt_regex=None, environ_update=None):
'''
Execute a command, returns rc, stdout, and stderr.