Commit 5dcab13e authored by Gerd Moellmann's avatar Gerd Moellmann

(state_protected_p, last_state_size, last_heapinfo)

[GC_MALLOC_CHECK && GC_PROTECT_MALLOC_STATE]: New variables.
(protect_malloc_state) [GC_MALLOC_CHECK &&
GC_PROTECT_MALLOC_STATE]: New function.
(PROTECT_MALLOC_STATE): New macro.
(__malloc_initialize, morecore, _malloc_internal)
(_free_internal) _realloc_internal): Use it to make _heapinfo
read-only outside of gmalloc.
parent a9839779
2000-10-24 Gerd Moellmann <gerd@gnu.org>
* gmalloc.c (state_protected_p, last_state_size, last_heapinfo)
[GC_MALLOC_CHECK && GC_PROTECT_MALLOC_STATE]: New variables.
(protect_malloc_state) [GC_MALLOC_CHECK &&
GC_PROTECT_MALLOC_STATE]: New function.
(PROTECT_MALLOC_STATE): New macro.
(__malloc_initialize, morecore, _malloc_internal)
(_free_internal) _realloc_internal): Use it to make _heapinfo
read-only outside of gmalloc.
* keymap.c: Update copyright.
* .gdbinit (xbacktrace): Handle case that $bt->function isn't
......
......@@ -380,6 +380,53 @@ __malloc_size_t __malloc_extra_blocks;
void (*__malloc_initialize_hook) PP ((void));
void (*__after_morecore_hook) PP ((void));
#if defined GC_MALLOC_CHECK && defined GC_PROTECT_MALLOC_STATE
/* Some code for hunting a bug writing into _heapinfo.
Call this macro with argument PROT non-zero to protect internal
malloc state against writing to it, call it with a zero argument to
make it readable and writable.
Note that this only works if BLOCKSIZE == page size, which is
the case on the i386. */
#include <sys/types.h>
#include <sys/mman.h>
static int state_protected_p;
static __malloc_size_t last_state_size;
static malloc_info *last_heapinfo;
void
protect_malloc_state (protect_p)
int protect_p;
{
/* If _heapinfo has been relocated, make sure its old location
isn't left read-only; it will be reused by malloc. */
if (_heapinfo != last_heapinfo
&& last_heapinfo
&& state_protected_p)
mprotect (last_heapinfo, last_state_size, PROT_READ | PROT_WRITE);
last_state_size = _heaplimit * sizeof *_heapinfo;
last_heapinfo = _heapinfo;
if (protect_p != state_protected_p)
{
state_protected_p = protect_p;
if (mprotect (_heapinfo, last_state_size,
protect_p ? PROT_READ : PROT_READ | PROT_WRITE) != 0)
abort ();
}
}
#define PROTECT_MALLOC_STATE(PROT) protect_malloc_state(PROT)
#else
#define PROTECT_MALLOC_STATE(PROT) /* empty */
#endif
/* Aligned allocation. */
static __ptr_t align PP ((__malloc_size_t));
......@@ -492,6 +539,7 @@ __malloc_initialize ()
register_heapinfo ();
__malloc_initialized = 1;
PROTECT_MALLOC_STATE (1);
return 1;
}
......@@ -516,6 +564,8 @@ morecore (size)
if (result == NULL)
return NULL;
PROTECT_MALLOC_STATE (0);
/* Check if we need to grow the info table. */
if ((__malloc_size_t) BLOCK ((char *) result + size) > heapsize)
{
......@@ -599,6 +649,7 @@ morecore (size)
it can relocate or resize the info table. */
_heaplimit = 0;
_free_internal (oldinfo);
PROTECT_MALLOC_STATE (0);
/* The new heap limit includes the new table just allocated. */
_heaplimit = BLOCK ((char *) newinfo + heapsize * sizeof (malloc_info));
......@@ -632,6 +683,8 @@ _malloc_internal (size)
return NULL;
#endif
PROTECT_MALLOC_STATE (0);
if (size < sizeof (struct list))
size = sizeof (struct list);
......@@ -680,11 +733,15 @@ _malloc_internal (size)
and break it into fragments, returning the first. */
#ifdef GC_MALLOC_CHECK
result = _malloc_internal (BLOCKSIZE);
PROTECT_MALLOC_STATE (0);
#else
result = malloc (BLOCKSIZE);
#endif
if (result == NULL)
return NULL;
{
PROTECT_MALLOC_STATE (1);
return NULL;
}
/* Link all fragments but the first into the free list. */
next = (struct list *) ((char *) result + (1 << log));
......@@ -803,6 +860,7 @@ _malloc_internal (size)
_heapinfo[block + blocks].busy.info.size = -blocks;
}
PROTECT_MALLOC_STATE (1);
return result;
}
......@@ -913,6 +971,8 @@ _free_internal (ptr)
if (ptr == NULL)
return;
PROTECT_MALLOC_STATE (0);
for (l = _aligned_blocks; l != NULL; l = l->next)
if (l->aligned == ptr)
{
......@@ -1035,6 +1095,7 @@ _free_internal (ptr)
/* Allocate new space for the info table and move its data. */
newinfo = (malloc_info *) _malloc_internal (info_blocks
* BLOCKSIZE);
PROTECT_MALLOC_STATE (0);
memmove (newinfo, _heapinfo, info_blocks * BLOCKSIZE);
_heapinfo = newinfo;
......@@ -1133,6 +1194,8 @@ _free_internal (ptr)
}
break;
}
PROTECT_MALLOC_STATE (1);
}
/* Return memory to the heap. */
......@@ -1296,6 +1359,8 @@ _realloc_internal (ptr, size)
block = BLOCK (ptr);
PROTECT_MALLOC_STATE (0);
type = _heapinfo[block].busy.type;
switch (type)
{
......@@ -1344,6 +1409,7 @@ _realloc_internal (ptr, size)
_heaplimit = 0;
_free_internal (ptr);
result = _malloc_internal (size);
PROTECT_MALLOC_STATE (0);
if (_heaplimit == 0)
_heaplimit = oldlimit;
if (result == NULL)
......@@ -1387,6 +1453,7 @@ _realloc_internal (ptr, size)
break;
}
PROTECT_MALLOC_STATE (1);
return result;
}
......
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