malloc: Remove dumped heap support

Remove support for obsolete dumped heaps.  Dumping heaps was discontinued
8 years ago, however loading a dumped heap is still supported. This blocks
changes and improvements of the malloc data structures - hence it is time
to remove this.  Ancient binaries that still call malloc_set_state will now
get the -1 error code.  Update tst-mallocstate.c to just check for this.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

1 files changed, 7 insertions, 158 deletions

diff --git a/malloc/malloc-debug.c b/malloc/malloc-debug.c
index 8bcb5652e0..0bb57841ee 100644
--- a/malloc/malloc-debug.c
+++ b/malloc/malloc-debug.c
@@ -150,19 +150,6 @@ memalign_hook_ini (size_t alignment, size_t sz, const void *caller)
 
 static size_t pagesize;
 
-/* These variables are used for undumping support.  Chunked are marked
-   as using mmap, but we leave them alone if they fall into this
-   range.  NB: The chunk size for these chunks only includes the
-   initial size field (of SIZE_SZ bytes), there is no trailing size
-   field (unlike with regular mmapped chunks).  */
-static mchunkptr dumped_main_arena_start; /* Inclusive.  */
-static mchunkptr dumped_main_arena_end;   /* Exclusive.  */
-
-/* True if the pointer falls into the dumped arena.  Use this after
-   chunk_is_mmapped indicates a chunk is mmapped.  */
-#define DUMPED_MAIN_ARENA_CHUNK(p) \
-  ((p) >= dumped_main_arena_start && (p) < dumped_main_arena_end)
-
 /* The allocator functions.  */
 
 static void *
@@ -202,9 +189,7 @@ __debug_free (void *mem)
   if (__is_malloc_debug_enabled (MALLOC_MCHECK_HOOK))
     mem = free_mcheck (mem);
 
-  if (DUMPED_MAIN_ARENA_CHUNK (mem2chunk (mem)))
-    /* Do nothing.  */;
-  else if (__is_malloc_debug_enabled (MALLOC_CHECK_HOOK))
+  if (__is_malloc_debug_enabled (MALLOC_CHECK_HOOK))
     free_check (mem);
   else
     __libc_free (mem);
@@ -227,32 +212,7 @@ __debug_realloc (void *oldmem, size_t bytes)
   if ((!__is_malloc_debug_enabled (MALLOC_MCHECK_HOOK)
        || !realloc_mcheck_before (&oldmem, &bytes, &oldsize, &victim)))
     {
-      mchunkptr oldp = mem2chunk (oldmem);
-
-      /* If this is a faked mmapped chunk from the dumped main arena,
-	 always make a copy (and do not free the old chunk).  */
-      if (DUMPED_MAIN_ARENA_CHUNK (oldp))
-	{
-	  if (bytes == 0 && oldmem != NULL)
-	    victim = NULL;
-	  else
-	    {
-	      const INTERNAL_SIZE_T osize = chunksize (oldp);
-	      /* Must alloc, copy, free. */
-	      victim = __debug_malloc (bytes);
-	      /* Copy as many bytes as are available from the old chunk
-		 and fit into the new size.  NB: The overhead for faked
-		 mmapped chunks is only SIZE_SZ, not CHUNK_HDR_SZ as for
-		 regular mmapped chunks.  */
-	      if (victim != NULL)
-		{
-		  if (bytes > osize - SIZE_SZ)
-		    bytes = osize - SIZE_SZ;
-		  memcpy (victim, oldmem, bytes);
-		}
-	    }
-	}
-      else if (__is_malloc_debug_enabled (MALLOC_CHECK_HOOK))
+      if (__is_malloc_debug_enabled (MALLOC_CHECK_HOOK))
 	victim =  realloc_check (oldmem, bytes);
       else
 	victim = __libc_realloc (oldmem, bytes);
@@ -414,10 +374,6 @@ malloc_usable_size (void *mem)
   if (__is_malloc_debug_enabled (MALLOC_CHECK_HOOK))
     return malloc_check_get_size (mem);
 
-  mchunkptr p = mem2chunk (mem);
-  if (DUMPED_MAIN_ARENA_CHUNK (p))
-    return chunksize (p) - SIZE_SZ;
-
   return musable (mem);
 }
 
@@ -517,43 +473,10 @@ malloc_trim (size_t s)
 
 #if SHLIB_COMPAT (libc_malloc_debug, GLIBC_2_0, GLIBC_2_25)
 
-/* Support for restoring dumped heaps contained in historic Emacs
-   executables.  The heap saving feature (malloc_get_state) is no
-   longer implemented in this version of glibc, but we have a heap
-   rewriter in malloc_set_state which transforms the heap into a
-   version compatible with current malloc.  */
-
-#define MALLOC_STATE_MAGIC   0x444c4541l
-#define MALLOC_STATE_VERSION (0 * 0x100l + 5l) /* major*0x100 + minor */
-
-struct malloc_save_state
-{
-  long magic;
-  long version;
-  mbinptr av[NBINS * 2 + 2];
-  char *sbrk_base;
-  int sbrked_mem_bytes;
-  unsigned long trim_threshold;
-  unsigned long top_pad;
-  unsigned int n_mmaps_max;
-  unsigned long mmap_threshold;
-  int check_action;
-  unsigned long max_sbrked_mem;
-  unsigned long max_total_mem;	/* Always 0, for backwards compatibility.  */
-  unsigned int n_mmaps;
-  unsigned int max_n_mmaps;
-  unsigned long mmapped_mem;
-  unsigned long max_mmapped_mem;
-  int using_malloc_checking;
-  unsigned long max_fast;
-  unsigned long arena_test;
-  unsigned long arena_max;
-  unsigned long narenas;
-};
-
-/* Dummy implementation which always fails.  We need to provide this
-   symbol so that existing Emacs binaries continue to work with
-   BIND_NOW.  */
+/* Support for saving/restoring dumped heaps in old GLIBCs is no
+   longer implemented - instead we provide dummy implementations
+   which always fail.  We need to provide these symbol so that
+   existing Emacs binaries continue to work with BIND_NOW.  */
 void *
 malloc_get_state (void)
 {
@@ -566,81 +489,7 @@ compat_symbol (libc_malloc_debug, malloc_get_state, malloc_get_state,
 int
 malloc_set_state (void *msptr)
 {
-  struct malloc_save_state *ms = (struct malloc_save_state *) msptr;
-
-  if (ms->magic != MALLOC_STATE_MAGIC)
-    return -1;
-
-  /* Must fail if the major version is too high. */
-  if ((ms->version & ~0xffl) > (MALLOC_STATE_VERSION & ~0xffl))
-    return -2;
-
-  if (debug_initialized == 1)
-    return -1;
-
-  bool check_was_enabled = __is_malloc_debug_enabled (MALLOC_CHECK_HOOK);
-
-  /* It's not too late, so disable MALLOC_CHECK_ and all of the hooks.  */
-  __malloc_hook = NULL;
-  __realloc_hook = NULL;
-  __free_hook = NULL;
-  __memalign_hook = NULL;
-  __malloc_debug_disable (MALLOC_CHECK_HOOK);
-
-  /* We do not need to perform locking here because malloc_set_state
-     must be called before the first call into the malloc subsystem (usually via
-     __malloc_initialize_hook).  pthread_create always calls calloc and thus
-     must be called only afterwards, so there cannot be more than one thread
-     when we reach this point.  Also handle initialization if either we ended
-     up being called before the first malloc or through the hook when
-     malloc-check was enabled.  */
-  if (debug_initialized < 0)
-    generic_hook_ini ();
-  else if (check_was_enabled)
-    __libc_free (__libc_malloc (0));
-
-  /* Patch the dumped heap.  We no longer try to integrate into the
-     existing heap.  Instead, we mark the existing chunks as mmapped.
-     Together with the update to dumped_main_arena_start and
-     dumped_main_arena_end, realloc and free will recognize these
-     chunks as dumped fake mmapped chunks and never free them.  */
-
-  /* Find the chunk with the lowest address with the heap.  */
-  mchunkptr chunk = NULL;
-  {
-    size_t *candidate = (size_t *) ms->sbrk_base;
-    size_t *end = (size_t *) (ms->sbrk_base + ms->sbrked_mem_bytes);
-    while (candidate < end)
-      if (*candidate != 0)
-	{
-	  chunk = mem2chunk ((void *) (candidate + 1));
-	  break;
-	}
-      else
-	++candidate;
-  }
-  if (chunk == NULL)
-    return 0;
-
-  /* Iterate over the dumped heap and patch the chunks so that they
-     are treated as fake mmapped chunks.  */
-  mchunkptr top = ms->av[2];
-  while (chunk < top)
-    {
-      if (inuse (chunk))
-	{
-	  /* Mark chunk as mmapped, to trigger the fallback path.  */
-	  size_t size = chunksize (chunk);
-	  set_head (chunk, size | IS_MMAPPED);
-	}
-      chunk = next_chunk (chunk);
-    }
-
-  /* The dumped fake mmapped chunks all lie in this address range.  */
-  dumped_main_arena_start = (mchunkptr) ms->sbrk_base;
-  dumped_main_arena_end = top;
-
-  return 0;
+  return -1;
 }
 compat_symbol (libc_malloc_debug, malloc_set_state, malloc_set_state,
 	       GLIBC_2_0);