tunables: sort tunables list (BZ 30027)

Sort tunables list at the time it's generated.  Note: adding new
tunables will cause other tunable IDs to change, but that was
the case before anyway.  POSIX does not guarantee the order of "foo
in bar" AWK operators, so the order was indeterminate before anyway.
Even depending on the order to be the same across multiple calls,
such as in this script, is undefined, so sorting the list resolves
that also.

Note that sorting is not dependent on the user's locale.

2 files changed, 12 insertions, 4 deletions

diff --git a/Makeconfig b/Makeconfig
index 2981936..2d4343b 100644
--- a/Makeconfig
+++ b/Makeconfig
@@ -1265,7 +1265,7 @@ $(common-objpfx)dl-tunable-list.stmp: \
 		$(..)elf/dl-tunables.list \
 		$(wildcard $(subdirs:%=$(..)%/dl-tunables.list)) \
 		$(wildcard $(sysdirs:%=%/dl-tunables.list))
-	$(AWK) -f $^ > ${@:stmp=T}
+	LC_ALL=C $(AWK) -f $^ > ${@:stmp=T}
 	$(move-if-change) ${@:stmp=T} ${@:stmp=h}
 	touch $@
 
diff --git a/scripts/gen-tunables.awk b/scripts/gen-tunables.awk
index fc3b413..d9f326b 100644
--- a/scripts/gen-tunables.awk
+++ b/scripts/gen-tunables.awk
@@ -131,6 +131,11 @@ END {
     exit 1
   }
 
+  # TYPES is an associative array where the index is the data
+  # TYPESA is an indexed array where the value is the data
+  # We sort TYPESA
+  typecount = asorti (types, typesa)
+
   print "/* AUTOGENERATED by gen-tunables.awk.  */"
   print "#ifndef _TUNABLES_H_"
   print "# error \"Do not include this file directly.\""
@@ -141,7 +146,8 @@ END {
   # Now, the enum names
   print "\ntypedef enum"
   print "{"
-  for (tnm in types) {
+  for (i = 1; i <= typecount; i++) {
+    tnm = typesa[i];
     split (tnm, indices, SUBSEP);
     t = indices[1];
     n = indices[2];
@@ -157,7 +163,8 @@ END {
   print "# include \"dl-tunable-types.h\""
   # Finally, the tunable list.
   print "static tunable_t tunable_list[] attribute_relro __attribute_used__ = {"
-  for (tnm in types) {
+  for (i = 1; i <= typecount; i++) {
+    tnm = typesa[i];
     split (tnm, indices, SUBSEP);
     t = indices[1];
     n = indices[2];
@@ -172,7 +179,8 @@ END {
   # Map of tunable with environment variables aliases used during parsing.  */
   print "\nstatic const tunable_id_t tunable_env_alias_list[] ="
   printf "{\n"
-  for (tnm in types) {
+  for (i = 1; i <= typecount; i++) {
+    tnm = typesa[i];
     split (tnm, indices, SUBSEP);
     t = indices[1];
     n = indices[2];