setup-hooks/strip: uniqify files by inode number before stripping

tpwrules · tpwrules · commit 4d6d293fad1a · 2024-05-24T16:53:14.000-05:00
#246164 but for hardlinks. Mesa, among other packages, has binaries that are linked together and can end up corrupted when the same binary is stripped through two different names. To resolve this, print out the device and inode number before each file name, sort/uniq based on that, then cut it back out before stripping. The symlink resolution logic is removed as the same file accessed through two different links in `$paths` will necessarily have the same numbers. File/directory within the paths listed in `$paths` are correctly not (and were never) processed due to the `-type f` predicate and (implied) `-P` option to `find`.
diff --git a/pkgs/build-support/setup-hooks/strip.sh b/pkgs/build-support/setup-hooks/strip.sh
@@ -74,13 +74,17 @@ stripDirs() {
         echo "stripping (with command $cmd and flags $stripFlags) in $paths"
         local striperr
         striperr="$(mktemp --tmpdir="$TMPDIR" 'striperr.XXXXXX')"
-        # Do not strip lib/debug. This is a directory used by setup-hooks/separate-debug-info.sh.
-        find $paths -type f "${excludeFlags[@]}" -a '!' -path "$prefix/lib/debug/*" -print0 |
-            # Make sure we process files under symlinks only once. Otherwise
-            # 'strip` can corrupt files when writes to them in parallel:
-            #   https://github.com/NixOS/nixpkgs/issues/246147#issuecomment-1657072039
-            xargs -r -0 -n1 -- realpath -z | sort -u -z |
+        # Make sure we process files only once. `strip`ping the same file through different
+        # links in parallel can corrupt it:
+        #   https://github.com/NixOS/nixpkgs/issues/246147#issuecomment-1657072039
 
+        # Do not strip lib/debug. This is a directory used by setup-hooks/separate-debug-info.sh.
+        # Print out each file's device and inode (which will be the same if two files are hardlinked
+        # or are the same file found through different symlinks), followed by its path...
+        find $paths -type f "${excludeFlags[@]}" -a '!' -path "$prefix/lib/debug/*" -printf '%D-%i,%p\0' |
+            # ... sort/uniq by device/inode, then cut them out and keep the path, ...
+            sort -t, -k1,1 -u -z | cut -d, -f2- -z |
+            # and finally strip each unique path in parallel.
             xargs -r -0 -n1 -P "$NIX_BUILD_CORES" -- $cmd $stripFlags 2>"$striperr" || exit_code=$?
         # xargs exits with status code 123 if some but not all of the
         # processes fail. We don't care if some of the files couldn't
