import redhat-rpm-config-123-1.el8

SOURCES/brp-mangle-shebangs

@@ -70,13 +70,17 @@ done
 
 cd "$RPM_BUILD_ROOT"
 
-trim() {
-  printf '%s' "$*"
-}
-
+# Large packages such as kernel can have thousands of executable files.
+# We take care to not fork/exec thousands of "file"s and "grep"s,
+# but run just two of them.
+# (Take care to exclude filenames which would mangle "file" output).
+find -executable -type f ! -path '*:*' ! -path $'*\n*' \
+| file -N --mime-type -f - \
+| grep -P ".+(?=: text/)" \
+| {
 fail=0
-while IFS= read -r -d $'\0' f; do
-  file -N --mime-type "$f" | grep -q -P ".+(?=: text/)" || continue
+while IFS= read -r line; do
+  f=${line%%:*}
 
   # Remove the dot
   path="${f#.}"
@@ -88,24 +92,34 @@ while IFS= read -r -d $'\0' f; do
     echo "$path" | grep -q -E -f "$exclude_files_from" && continue
   fi
 
-  ts=$(stat -c %y "$f")
 
-  read shebang_line < "$f" || :
-  orig_shebang=$(trim $(echo "$shebang_line" | grep -Po "#!\K.*" || echo))
-  shebang="$orig_shebang"
-  if [ -n "$exclude_shebangs" ]; then
-    echo "$shebang" | grep -q -E "$exclude_shebangs" && continue
-  fi
-  if [ -n "$exclude_shebangs_from" ]; then
-    echo "$shebang" | grep -q -E -f "$exclude_shebangs_from" && continue
-  fi
-
-  if [ -z "$shebang" ]; then
-    echo >&2 "*** WARNING: $f is executable but has empty or no shebang, removing executable bit"
+  read shebang_line < "$f"
+  orig_shebang="${shebang_line#\#!}"
+  if [ "$orig_shebang" = "$shebang_line" ]; then
+    echo >&2 "*** WARNING: $f is executable but has no shebang, removing executable bit"
+    ts=$(stat -c %y "$f")
     chmod -x "$f"
     touch -d "$ts" "$f"
     continue
-  elif [ -n "${shebang##/*}" ]; then
+  fi
+
+  # Trim spaces
+  while shebang="${orig_shebang//  / }"; [ "$shebang" != "$orig_shebang" ]; do
+    orig_shebang="$shebang"
+  done
+  # Treat "#! /path/to " as "#!/path/to"
+  orig_shebang="${orig_shebang# }"
+
+  shebang="$orig_shebang"
+
+  if [ -z "$shebang" ]; then
+    echo >&2 "*** WARNING: $f is executable but has empty shebang, removing executable bit"
+    ts=$(stat -c %y "$f")
+    chmod -x "$f"
+    touch -d "$ts" "$f"
+    continue
+  fi
+  if [ -n "${shebang##/*}" ]; then
     echo >&2 "*** ERROR: $f has shebang which doesn't start with '/' ($shebang)"
     fail=1
     continue
@@ -134,11 +148,13 @@ while IFS= read -r -d $'\0' f; do
     echo >&2 "*** ERROR: ambiguous python shebang in $path: #!$orig_shebang. Change it to python3 (or python2) explicitly."
     fail=1
   elif [ "#!$shebang" != "#!$orig_shebang" ]; then
-    sed -i -e "1c #!$shebang" "$f"
     echo "mangling shebang in $path from $orig_shebang to #!$shebang"
+    ts=$(stat -c %y "$f")
+    sed -i -e "1c #!$shebang" "$f"
+    touch -d "$ts" "$f"
   fi
 
-  touch -d "$ts" "$f"
-done < <(find -executable -type f -print0)
+done
 
 exit $fail
+}

SOURCES/kmod.prov

@@ -1,17 +1,28 @@
 #!/bin/sh +x
+# Kernel build can have many thousands of modules.
+# kmod.prov is run for every one of them.
+# Try to make this script run as fast as we can.
+# For example, use shell string ops instead of external programs
+# where possible.
 
 IFS=$'\n'
 
-for i in $(grep -E '(/lib/modules/.*\.ko|/lib/modules/.*/modules.builtin)');
-do
-	kmod=$(basename $i | sed -e 's/.[xg]z//');
+read -r fname || exit
 
-	if [ $kmod == "modules.builtin" ]; then
-		for j in $(cat $i); do
-			j=$(basename $j);
-			echo "kmod($j)"
-		done
-	else
-		echo "kmod($kmod)"
-	fi
-done
+# Only process files from .../lib/modules/... subtree
+[ "${fname#*/lib/modules/*}" != "$fname" ] || exit 0
+
+kmod=${fname##*/}  # like basename, but faster
+
+if [ "$kmod" = "modules.builtin" ]; then
+        for j in $(cat -- "$fname"); do
+                echo "kmod(${j##*/})"
+        done
+        exit 0
+fi
+
+kmod=${kmod%.gz}
+kmod=${kmod%.xz}
+if [ "${kmod%.ko}" != "$kmod" ]; then
+        echo "kmod($kmod)"
+fi

SPECS/redhat-rpm-config.spec

@@ -6,7 +6,7 @@
 
 Summary: Red Hat specific rpm configuration files
 Name: redhat-rpm-config
-Version: 122
+Version: 123
 Release: 1%{?dist}
 # No version specified.
 License: GPL+
@@ -198,6 +198,10 @@ install -p -m 755 %{SOURCE21} %{buildroot}%{_rpmconfigdir}/kabi.sh
 %{_rpmconfigdir}/macros.d/macros.kmp
 
 %changelog
+* Tue Jun 16 2020 Florian Festi <ffesti@redhat.com> - 123-1
+- Update kmod.prov for better performance (#1794491)
+- Backport performance improvements for brp-mangle-shebangs (#1794779)
+
 * Mon Feb 24 2020 Michal Domonkos <mdomonko@redhat.com> - 122-1
 - Fix argument shift in %%__brp_python_bytecompile (#1724567)