Create a file with permissions that respects umask #2851
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**Problem** `Data.write(to:)` is a only method in the Foundation that can create a regular file. However, it ignores `uamask` and always set 0600 permission unlike macOS Foundation, which respects process `umask`. **Solution** 1. With `.atomic` write option It uses `mkstemp(3)` in `_NSCreateTemporaryFile`, which is always creating a file with 0600 permission, if the system follows the latest POSIX specification or the permission is undefined. On macOS Foundation, therefore `_NSCreateTemporaryFile` uses `mktemp(3)` and `open(2)` instead to respect `umask`. 2. Without `.atomic` write option It uses `0o600` even if it uses `open(2)` that respects `umask`. Simply gives `0o666` instead. This is a bug caused by previous commit in swiftlang#1876. JIRA: https://bugs.swift.org/browse/SR-13307
Contributor
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Could you add a regression test that validates that a file is created with the correct permissions, thanks |
Contributor
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@swift-ci test |
Contributor
Author
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@spevans Sure! the test need to change process’s |
Contributor
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@swift-ci please test |
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Problem
Data.write(to:)is a only method in the Foundation that can create aregular file.
However, it ignores
umaskand always set 0600 permission unlikemacOS Foundation, which respects process
umask.Solution
With
.atomicwrite optionIt uses
mkstemp(3)in_NSCreateTemporaryFile, which is alwayscreating a file with 0600 permission, if the system follows
the latest POSIX specification or the permission is undefined.
On macOS Foundation, therefore
_NSCreateTemporaryFileusesmktemp(3)andopen(2)instead to respectumask.Without
.atomicwrite optionIt uses
0o600even if it usesopen(2)that respectsumask.Simply gives
0o666instead.This is a bug caused by previous commit in
#1876.
Swift JIRA is https://bugs.swift.org/browse/SR-13307.