tunables: Fix comparison of tunable values

The simplification of tunable_set interfaces took care of
signed/unsigned conversions while setting values, but comparison with
bounds ended up being incorrect; comparing TUNABLE_SIZE_T values for
example will fail because SIZE_MAX is seen as -1.

Add comparison helpers that take tunable types into account and use
them to do comparison instead.

1 files changed, 18 insertions, 0 deletions

diff --git a/elf/dl-tunables.h b/elf/dl-tunables.h
index ba7ae6b52e..3880e4aab6 100644
--- a/elf/dl-tunables.h
+++ b/elf/dl-tunables.h
@@ -115,6 +115,24 @@ rtld_hidden_proto (__tunable_set_val)
 /* The default value for TUNABLES_FRONTEND.  */
 # define TUNABLES_FRONTEND_yes TUNABLES_FRONTEND_valstring
 
+static __always_inline bool
+tunable_val_lt (tunable_num_t lhs, tunable_num_t rhs, bool unsigned_cmp)
+{
+  if (unsigned_cmp)
+    return (uintmax_t) lhs < (uintmax_t) rhs;
+  else
+    return lhs < rhs;
+}
+
+static __always_inline bool
+tunable_val_gt (tunable_num_t lhs, tunable_num_t rhs, bool unsigned_cmp)
+{
+  if (unsigned_cmp)
+    return (uintmax_t) lhs > (uintmax_t) rhs;
+  else
+    return lhs > rhs;
+}
+
 /* Compare two name strings, bounded by the name hardcoded in glibc.  */
 static __always_inline bool
 tunable_is_name (const char *orig, const char *envname)