I've endeavoured to improve on my previous patch, by adopting a
heuristic approach as follows:
1) First and foremost, for each file in the backup copy I try and
assign permissions based on those of the corresponding file in the
source repository, if the latter does indeed exist.
2) Should this fail, I infer the permissions from the context, i.e. I
choose one "typical file" from the same folder.
3) Should the folder itself be empty, I assign permissions based on
the current umask.
Do you deem such an approach to be correct?
Regards,
Roberto
On Thu, Oct 22, 2015 at 4:20 PM, Roberto Reale
<[email protected]> wrote:
> Which behaviour would you deem correct?
>
> Just assigning a default permission set when the original file cannot
> be found, or inferring it from the file type (e.g., revision files
> should not be executable)?
>
> Regards,
> Roberto
>
> On Thu, Oct 22, 2015 at 1:12 PM, Philip Martin
> <[email protected]> wrote:
>> Roberto Reale <[email protected]> writes:
>>
>>> Do you think the patch can be improved in any regards?
>>>
>>> I would like to "breed it up", so to say, to an acceptable status.
>>
>> Your patch assumes that all the files in the backup are still present in
>> the source repository and that is not always true. For example pack on
>> a FSFS repository could remove revision files, a commit to a BDB
>> repository could delete a log file. Any such files will cause archive
>> creation to fail with your patch.
>>
>> --
>> Philip Martin
>> WANdisco
[[[
* tools/backup/hot-backup.py.in: Always save correct file
permissions in tar archives.
]]]
Index: tools/backup/hot-backup.py.in
===================================================================
--- tools/backup/hot-backup.py.in (revision 1706408)
+++ tools/backup/hot-backup.py.in (working copy)
@@ -292,7 +292,61 @@ if archive_type:
try:
import tarfile
tar = tarfile.open(archive_path, 'w:' + archive_type)
- tar.add(backup_subdir, os.path.basename(backup_subdir))
+
+ # Build up the archive file by file, paying special care in replicating
+ # the permissions for each file from the source repository itself rather
+ # than from the hotcopy dump.
+ #
+ # This can be useful in such cases when the source repository is on a
+ # POSIX filesystem and the hotcopy dump is written e.g. on a FAT or a
+ # CIFS filesystem, thus leading to a possible "permission leakage" were
+ # the archive built directly from hotcopy dump via tar.add().
+ #
+ # Since, however, nothing guarantees that all the files in the backup are
+ # still present in the source repository (due e.g. to revision files
+ # being removed by pack on a FSFS repository, or to a log file being
+ # deleted by a commit to a BDB repository), we are forced to resort to a
+ # heuristic approach.
+ #
+ # First and foremost, we try and assign permissions based on those of the
+ # corresponding file in the source repository (case marked S below).
+ # Should this fail, we infer them from the context, i.e. we choose one
+ # "typical file" from the same folder (case C). Should the folder itself
+ # be empty, we assign permissions based on the current umask (case U).
+
+ for dirpath, dirnames, filenames in os.walk(backup_subdir,
followlinks=True):
+ for leafname in dirnames + filenames:
+ backup_based_path = os.path.join(dirpath, leafname)
+ relpath = os.path.relpath(backup_based_path, backup_subdir)
+ repo_based_path = os.path.join(repo_dir, relpath)
+ if not os.path.exists(repo_based_path):
+ # (C) Infer permissions from some "typical file" to be found
+ # underneath the same folder.
+ def choose_one_file_in_path(path):
+ files_in_path = [f for f in os.listdir(path)
+ if os.path.isfile(os.path.join(path, f))]
+ if files_in_path:
+ return files_in_path[0]
+ repo_based_p_path = os.path.dirname(repo_based_path) # "parent
path"
+ typical_file_in_path = choose_one_file_in_path(repo_based_p_path)
+ if not typical_file_in_path:
+ repo_based_path = None
+ repo_based_path = os.path.join(repo_based_p_path,
typical_file_in_path)
+ tarinfo = tar.gettarinfo(backup_based_path, os.path.join(repo,
relpath))
+ if not repo_based_path:
+ # (S) Assign permissions based on those of the corresponding file
+ # in the source repository.
+ tarinfo.mode = os.stat(repo_based_path).st_mode
+ else:
+ # (U) Assign permissions based on the current umask.
+ current_umask = os.umask(0)
+ os.umask(current_umask)
+ tarinfo.mode = 0777 ^ current_umask
+ if tarinfo.isreg():
+ with open(backup_based_path, "rb") as f:
+ tar.addfile(tarinfo, f)
+ else:
+ tar.addfile(tarinfo)
tar.close()
except ImportError, e:
err_msg = "Import failed: " + str(e)
