From 836573a9a2d38935e254702826d250ea39824a1b Mon Sep 17 00:00:00 2001 From: Eelco Dolstra Date: Tue, 31 Oct 2017 12:22:29 +0100 Subject: Dynamically allocate UIDs Rather than rely on a nixbld group, we now allocate UIDs/GIDs dynamically starting at a configurable ID (872415232 by default). Also, we allocate 2^18 UIDs and GIDs per build, and run the build as root in its UID namespace. (This should not be the default since it breaks some builds. We probably should enable this conditional on a requiredSystemFeature.) The goal is to be able to run (NixOS) containers in a build. However, this will also require some cgroup initialisation. The 2^18 UIDs/GIDs is intended to provide enough ID space to run multiple containers per build, e.g. for distributed NixOS tests. --- src/libstore/globals.hh | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'src/libstore/globals.hh') diff --git a/src/libstore/globals.hh b/src/libstore/globals.hh index 58cf08763..7dc842bca 100644 --- a/src/libstore/globals.hh +++ b/src/libstore/globals.hh @@ -148,6 +148,16 @@ public: Setting buildUsersGroup{this, "", "build-users-group", "The Unix group that contains the build users."}; + #if __linux__ + const uint32_t idsPerBuild = 1 << 18; + + Setting startId{this, 872415232, "start-id", + "The first UID and GID to use for dynamic ID allocation. (0 means disable.)"}; + + Setting uidCount{this, idsPerBuild * 128, "id-count", + "The number of UIDs/GIDs to use for dynamic ID allocation."}; + #endif + Setting impersonateLinux26{this, false, "impersonate-linux-26", "Whether to impersonate a Linux 2.6 machine on newer kernels.", {"build-impersonate-linux-26"}}; -- cgit v1.2.3