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zipfile: symlinks etc. #62795

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ronaldoussoren opened this issue Jul 30, 2013 · 6 comments
Closed

zipfile: symlinks etc. #62795

ronaldoussoren opened this issue Jul 30, 2013 · 6 comments
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stdlib Python modules in the Lib dir type-feature A feature request or enhancement

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@ronaldoussoren
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BPO 18595
Nosy @jcea, @ronaldoussoren, @takluyver, @serhiy-storchaka

Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.

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GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2013-07-30.07:45:18.689>
labels = ['type-feature', 'library']
title = 'zipfile: symlinks etc.'
updated_at = <Date 2016-01-15.15:20:56.539>
user = 'https://github.com/ronaldoussoren'

bugs.python.org fields:

activity = <Date 2016-01-15.15:20:56.539>
actor = 'takluyver'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2013-07-30.07:45:18.689>
creator = 'ronaldoussoren'
dependencies = []
files = []
hgrepos = []
issue_num = 18595
keywords = []
message_count = 5.0
messages = ['193915', '194234', '194240', '194264', '252482']
nosy_count = 5.0
nosy_names = ['jcea', 'ronaldoussoren', 'takluyver', 'serhiy.storchaka', 'xcombelle']
pr_nums = []
priority = 'normal'
resolution = None
stage = 'needs patch'
status = 'open'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue18595'
versions = ['Python 3.5']
@ronaldoussoren
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The zipfile format (as described by .zip file format specification) allows for storing extra unix data, such as symlinks and device nodes in zipfile.

Storing at least symlinks would be useful, and is supported by the infozip tools as well (the command-line zip and unzip commands on Linux systems).

An implementation would use the "UNIX Extra Field (0x000d)" to store this information.

@ronaldoussoren ronaldoussoren added stdlib Python modules in the Lib dir type-feature A feature request or enhancement labels Jul 30, 2013
@jcea
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jcea commented Aug 3, 2013

Ronald, could you try to write a patch?

@ronaldoussoren
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My initial plan was to add the patch soon after filing the issue, but that's before I noticed that this needs some API design to integrate nicely :-)

My current idea for the api:

  • add "symlink(path, target") to write a symlink

  • add "readlink(path)" to read a symlink

  • "read" will raise an exception when trying to read a symlink
    (alternative: do symlink resolving, but that's too magical to my taste)

  • "extract" and "extractall" extract the symlink as a symlink
    (but I'm not sure yet what to do on systems that don't support symlinks)

  • with the various file types it might be better to also provide
    "islink(name)", "isdir(name)" and "isfile(name)" methods (simular to
    their os.path equivalents)

This will also require some changes to the ZipInfo class.

I'm not sure yet if adding support for device files and other unix attributes (UID/GID).

@serhiy-storchaka
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  • "read" will raise an exception when trying to read a symlink
    (alternative: do symlink resolving, but that's too magical to my taste)

And perhaps when trying to read a directory entry too.

  • "extract" and "extractall" extract the symlink as a symlink
    (but I'm not sure yet what to do on systems that don't support symlinks)

What the tar module do?

  • with the various file types it might be better to also provide
    "islink(name)", "isdir(name)" and "isfile(name)" methods (simular to
    their os.path equivalents)

Or rather as methods of the ZipInfo object. See TarInfo.

@xcombelle
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xcombelle mannequin commented Oct 7, 2015

about the readlink functionnality, I would like to point that it might lead to security issues see for example https://security.stackexchange.com/questions/73718/how-zip-symlink-works

At least, the standard read should not do it by default.

@ezio-melotti ezio-melotti transferred this issue from another repository Apr 10, 2022
@gpshead
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gpshead commented Sep 25, 2022

closing as a duplicate of #82102

@gpshead gpshead closed this as completed Sep 25, 2022
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