glibc.malloc.check: Wean away from malloc hooks

The malloc-check debugging feature is tightly integrated into glibc
malloc, so thanks to an idea from Florian Weimer, much of the malloc
implementation has been moved into libc_malloc_debug.so to support
malloc-check.  Due to this, glibc malloc and malloc-check can no
longer work together; they use altogether different (but identical)
structures for heap management.  This should not make a difference
though since the malloc check hook is not disabled anywhere.
malloc_set_state does, but it does so early enough that it shouldn't
cause any problems.

The malloc check tunable is now in the debug DSO and has no effect
when the DSO is not preloaded.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>

1 files changed, 5 insertions, 12 deletions

diff --git a/malloc/arena.c b/malloc/arena.c
index 840426f9fb..edcaa8816d 100644
--- a/malloc/arena.c
+++ b/malloc/arena.c
@@ -79,7 +79,9 @@ static __thread mstate thread_arena attribute_tls_model_ie;
    acquired after free_list_lock has been acquired.  */
 
 __libc_lock_define_initialized (static, free_list_lock);
+#if IS_IN (libc)
 static size_t narenas = 1;
+#endif
 static mstate free_list;
 
 /* list_lock prevents concurrent writes to the next member of struct
@@ -207,14 +209,6 @@ __malloc_fork_unlock_child (void)
 }
 
 #if HAVE_TUNABLES
-static void
-TUNABLE_CALLBACK (set_mallopt_check) (tunable_val_t *valp)
-{
-  int32_t value = (int32_t) valp->numval;
-  if (value != 0)
-    __malloc_check_init ();
-}
-
 # define TUNABLE_CALLBACK_FNDECL(__name, __type) \
 static inline int do_ ## __name (__type value);				      \
 static void									      \
@@ -309,7 +303,7 @@ ptmalloc_init (void)
     }
 #endif
 
-#ifdef SHARED
+#if defined SHARED && IS_IN (libc)
   /* In case this libc copy is in a non-default namespace, never use
      brk.  Likewise if dlopened from statically linked program.  The
      generic sbrk implementation also enforces this, but it is not
@@ -323,7 +317,6 @@ ptmalloc_init (void)
   malloc_init_state (&main_arena);
 
 #if HAVE_TUNABLES
-  TUNABLE_GET (check, int32_t, TUNABLE_CALLBACK (set_mallopt_check));
   TUNABLE_GET (top_pad, size_t, TUNABLE_CALLBACK (set_top_pad));
   TUNABLE_GET (perturb, int32_t, TUNABLE_CALLBACK (set_perturb_byte));
   TUNABLE_GET (mmap_threshold, size_t, TUNABLE_CALLBACK (set_mmap_threshold));
@@ -401,8 +394,6 @@ ptmalloc_init (void)
             }
         }
     }
-  if (s && s[0] != '\0' && s[0] != '0')
-    __malloc_check_init ();
 #endif
 }
 
@@ -672,6 +663,7 @@ heap_trim (heap_info *heap, size_t pad)
 
 /* Create a new arena with initial size "size".  */
 
+#if IS_IN (libc)
 /* If REPLACED_ARENA is not NULL, detach it from this thread.  Must be
    called while free_list_lock is held.  */
 static void
@@ -947,6 +939,7 @@ arena_get_retry (mstate ar_ptr, size_t bytes)
 
   return ar_ptr;
 }
+#endif
 
 void
 __malloc_arena_thread_freeres (void)