04/16: daemon: Bind-mount /etc/nsswitch.conf & co. only if it exists.

[guix-commits]

civodul pushed a commit to branch master
in repository guix.

commit 5c0b93b2441c338ad8dda97c64a54832be76840d
Author: Ludovic Courtès <l...@gnu.org>
AuthorDate: Mon Feb 24 17:29:25 2025 +0100

    daemon: Bind-mount /etc/nsswitch.conf & co. only if it exists.
    
    Those files may be missing in some contexts, for instance within the
    build environment.
    
    * nix/libstore/build.cc (DerivationGoal::runChild): Add /etc/resolv.conf
    and related files to ‘ss’ only if they exist.
    
    Change-Id: Ie19664a86c8101a1dc82cf39ad4b7abb10f8250a
---
 nix/libstore/build.cc | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/nix/libstore/build.cc b/nix/libstore/build.cc
index edd01bab34..8ca5e5b732 100644
--- a/nix/libstore/build.cc
+++ b/nix/libstore/build.cc
@@ -2093,10 +2093,11 @@ void DerivationGoal::runChild()
                network, so give them access to /etc/resolv.conf and so
                on. */
             if (fixedOutput) {
-                ss.push_back("/etc/resolv.conf");
-                ss.push_back("/etc/nsswitch.conf");
-                ss.push_back("/etc/services");
-                ss.push_back("/etc/hosts");
+               auto files = { "/etc/resolv.conf", "/etc/nsswitch.conf",
+                              "/etc/services", "/etc/hosts" };
+               for (auto & file: files) {
+                   if (pathExists(file)) ss.push_back(file);
+               }
             }
 
             for (auto & i : ss) dirsInChroot[i] = i;