[PATCH] modutils completion: Fix FHS assumption

[doron.behar@gmail.com]

From: Doron Behar <doron.behar@gmail.com>

---
 Completion/Linux/Command/_modutils | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/Completion/Linux/Command/_modutils b/Completion/Linux/Command/_modutils
index ff6844f41..a0ed7b210 100644
--- a/Completion/Linux/Command/_modutils
+++ b/Completion/Linux/Command/_modutils
@@ -12,7 +12,18 @@ _modules_caching_policy()
 _modutils() {
   local curcontext="$curcontext" expl state line modules modaliases ign args ret=1
   local -A opt_args
-  local -r modules_dir=/lib/modules
+  local -a possible_modules_dirs=(
+    # NixOS & possibly Guix
+    /run/booted-system/kernel-modules/lib/modules
+    # Mostly every other distro
+    /lib/modules
+  )
+  local modules_dir tested_modules_dir
+  for tested_modules_dir in "${possible_modules_dirs[@]}"; do
+    if [[ -d "$tested_modules_dir" ]]; then
+      modules_dir="$tested_modules_dir"
+    fi
+  done
 
   local update_policy
   zstyle -s ":completion:*:*:$service:*" cache-policy update_policy
@@ -108,6 +119,9 @@ _modutils() {
     all-modules)
       local kver=${opt_args[(i)(-S|-k|--set-version)]:-$(uname -r)}
 
+      if [[ -z "$modules_dir" ]]; then
+        return
+      fi
       if _cache_invalid modules-$kver || ! _retrieve_cache modules-$kver;
       then
 	modules=( $modules_dir/$kver/(*~(source|build))/**/*.(o|ko|ko.gz|ko.xz)(.:t:r:r) )
-- 
2.26.2