[LU-13335] add name lookup for project IDs

• Type: Improvement
• Resolution: Unresolved
• Priority: Minor
• Labels: lug23dd lug24dd medium patch utils
• Assignee: Fred Dilger
• Reporter: Andreas Dilger

Description

It would be useful to allow names to be mapped to projid numbers using the /etc/projid file (projid.5), as is used by the XFS quota utility (xfs_quota.8):

usera:1
userc:3

There should be a new function struct ll_project *llapi_getprjname(const char *name) function that is called by lfs and lctl to read the /etc/projid file and lookup the name and return the projid, while struct ll_project *llapi_getprjid(__u32 prjid) would lookup the numeric project ID and return the name:

struct ll_project {
        __u32 lp_projid;
        char *lp_name;
};

Returning the struct instead of a single value (name or prjid) allows expanding this interface in the future (e.g. to list which users are allowed to use/change the group, passwords for the group, etc. as with getgrnam(), getgrgid(), getpwnam(), getpwuid()).

It isn't very clear what benefit the /etc/projects file (projects.5) provides, so I'm not yet sure whether we need to implement support for this or not.

This should be available for use by lfs project -p, lfs find -projid, lfs quota -p, lfs setquota -p.

Issue Links

• has to be done before: LU-18659 add new 'lfs projectadd' command to add project entries to the /etc/projid file
• has to be done before: LU-18638 print project name with 'lfs project'
• has to be done before: LU-18640 add option for 'lfs project' to do project name and id lookup only
• is related to: LU-14915 Add project flags to manage the project's directories and files
• is related to: LU-14968 add password for project files
• is related to: LU-17702 'lfs quota -u $USER' should print quota for all Lustre mountpoints
• is related to: LU-12056 tar doesn't support project id
• is related to: LU-18661 allow enable/disable projname->username fallback

Comments

[Andreas Dilger]

I've filed LU-18661 to track the enable/disable implicit fallback to username/groupname.

[Gerrit Updater]

"Frederick Dilger <[e-mail]>" uploaded a new patch: https://review.whamcloud.com/c/fs/lustre-release/+/57836
Subject: LU-13335 utils: allow using uid and gid for prjid
Project: fs/lustre-release
Branch: master
Current Patch Set: 1
Commit: dfca145f5da870d205b8a855e3f893625e442820

[Andreas Dilger]

Attached prototype man page projid.5 to describe the base functionality and limitations.

[Andreas Dilger]

For the "/etc/passwd" fallback, we've been discussing a few approaches:

• store some directive as a comment in the file, like "# config: projname=passwd" or "# config: projname=group" that would redirect all future projname or projid lookups to use getpwnam()/getpwuid() or getgrnam()/getgrgid() as appropriate to look up the supplied name/ID. This has the advantage that it maintains compatibility with XFS, but means that all of the comment lines need to be parsed.
• store some directive as a "special" entry, like "*:passwd:use passwd entry for projid mapping" or "*:group:use group entry for projid mapping", which simplifies the parsing to some extent, but would likely break compatibility with XFS entries.

Alternately, this could be opt-in on the command-line by specifying a "project name" like "-p u:adilger" or "-p g:adilger" to do a user or group database lookup,

Reviewing the Solaris projects(5) man page I see that it is using project names of the form user.USERNAME and group.GROUPNAME" to identify project names to match the username, but which could also be used in addition to or instead of "u:USERNAME". I'm a bit reluctant to allow '.' in the argument. According to this Serverfault page the use of '.' is normally forbidden in user/group names, but I'd prefer to avoid any unnecessary restrictions if possible.