libc/grp: add getgrouplist()#19183
Open
xiaoxiang781216 wants to merge 1 commit into
Open
Conversation
Add getgrouplist() to the C library. It scans the group database for a user's supplementary groups and always reports the primary group first. Without CONFIG_LIBC_GROUP_FILE only the primary group is returned, since no membership information is available. The group file is read through lib_get_tempbuffer()/lib_put_tempbuffer() to avoid a heap allocation on every lookup. Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
github-actions
Bot
added
Area: OS Components
|
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Summary
Add
getgrouplist()to the C library. It scans the group database fora user's supplementary groups and always reports the primary group
(passed by the caller) first.
whose member list contains the user is appended, skipping the primary
group to avoid duplicates.
since no membership information is available.
buffer is too small the function returns -1 with *ngroups set to the
required count, following glibc.
The group file is read through lib_get_tempbuffer()/lib_put_tempbuffer()
to avoid a heap allocation on every lookup.
Impact
New GNU/BSD API declared in <grp.h>. No change to existing behavior or
build for code that does not call getgrouplist(). Helps porting
third-party software that expects getgrouplist() to be available.
Testing
Built the sim:nsh configuration on Linux (x86_64, GCC) with
CONFIG_LIBC_GROUP_FILE both enabled and disabled, and exercised
getgrouplist() against a crafted /etc/group with a user in multiple
groups (correct count and gid list; -1 with required count on a
too-small buffer). checkpatch.sh passes on the changed files.