From b84cf93cb9fc399366212fd1aa4c3b8faf18575c Mon Sep 17 00:00:00 2001 From: Simon Ruderich Date: Mon, 10 Jun 2019 23:40:00 +0200 Subject: [PATCH] README: document practices and tested systems --- README | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/README b/README index c416e42..a6d40b5 100644 --- a/README +++ b/README @@ -17,6 +17,22 @@ C, which provides integration via `/etc/nsswitch.conf`. It's specifically designed to be very simple and uses the data prepared by `nsscash` for lookups. To support quick lookups, in O(log n), the files utilize indices. +Nsscash is very careful when deploying the changes: +- All files are updated using the standard "write to temporary file", "sync", + "rename" steps which is atomic on UNIX file systems. +- All errors cause an immediate abort ("fail fast") with a proper error + message and a non-zero exit status. This prevents hiding possibly important + errors. In addition all files are fetched first and then deployed to try to + prevent inconsistent state if only one file can be downloaded. The state + file (containing last file modifications) is only updated when all + operations were successful. +- To prevent unexpected permissions, `nsscash` does not create new files. The + user must create them first and `nsscash` will then re-use the permissions + and owner/group when updating the file (see examples below). +- To prevent misconfigurations, empty files (no users/groups) are not + permitted and will not be written to disk. This is designed to prevent the + accidental loss of all users/groups on a system. + nsscash is licensed under AGPL version 3 or later. [1] https://github.com/google/nsscache @@ -29,6 +45,10 @@ nsscash is licensed under AGPL version 3 or later. - github.com/BurntSushi/toml - C compiler, for `libnss_cash.so.2` +Tested on Debian Stretch and Buster, but should work on any GNU/Linux system. +With adapations to the NSS module it should work on any UNIX-like system which +uses NSS. + == USAGE -- 2.45.2