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authorJakub Jelinek <jakub@redhat.com>2007-05-07 15:30:57 +0000
committerJakub Jelinek <jakub@redhat.com>2007-05-07 15:30:57 +0000
commitc7fd336280f2d88be4a22303199323718c8c3a28 (patch)
tree5fa83737189b7e0acdd5ba025b633326386ed74f /malloc
parent6780bc44e8b651cc67dbef2761fc92bdee46c45e (diff)
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* malloc/arena.c (heap_info): Add mprotect_size field, adjust pad.
(new_heap): Initialize mprotect_size. (grow_heap): When growing, only mprotect from mprotect_size till new_size if mprotect_size is smaller. When shrinking, use PROT_NONE MMAP for __libc_enable_secure only, otherwise use MADV_DONTNEED. 2007-05-07 Ulrich Drepper <drepper@redhat.com> Jakub Jelinek <jakub@redhat.com> * malloc/arena.c (heap_info): Add mprotect_size field, adjust pad. (new_heap): Initialize mprotect_size. (grow_heap): When growing, only mprotect from mprotect_size till new_size if mprotect_size is smaller. When shrinking, use PROT_NONE MMAP for __libc_enable_secure only, otherwise use MADV_DONTNEED.
Diffstat (limited to 'malloc')
-rw-r--r--malloc/Makefile1
-rw-r--r--malloc/arena.c37
2 files changed, 30 insertions, 8 deletions
diff --git a/malloc/Makefile b/malloc/Makefile
index c39eae5474..c251bcfb9d 100644
--- a/malloc/Makefile
+++ b/malloc/Makefile
@@ -104,6 +104,7 @@ $(objpfx)memusagestat: $(memusagestat-modules:%=$(objpfx)%.o)
include ../Rules
CFLAGS-mcheck-init.c = $(PIC-ccflag)
+CFLAGS-malloc.c += -DMALLOC_DEBUG
$(objpfx)libmcheck.a: $(objpfx)mcheck-init.o
-rm -f $@
diff --git a/malloc/arena.c b/malloc/arena.c
index 1d9f952112..ce64335567 100644
--- a/malloc/arena.c
+++ b/malloc/arena.c
@@ -1,5 +1,6 @@
/* Malloc implementation for multiple threads without lock contention.
- Copyright (C) 2001,2002,2003,2004,2005,2006 Free Software Foundation, Inc.
+ Copyright (C) 2001,2002,2003,2004,2005,2006,2007
+ Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Wolfram Gloger <wg@malloc.de>, 2001.
@@ -59,10 +60,12 @@ typedef struct _heap_info {
mstate ar_ptr; /* Arena for this heap. */
struct _heap_info *prev; /* Previous heap. */
size_t size; /* Current size in bytes. */
+ size_t mprotect_size; /* Size in bytes that has been mprotected
+ PROT_READ|PROT_WRITE. */
/* Make sure the following data is properly aligned, particularly
that sizeof (heap_info) + 2 * SIZE_SZ is a multiple of
- MALLOG_ALIGNMENT. */
- char pad[-5 * SIZE_SZ & MALLOC_ALIGN_MASK];
+ MALLOC_ALIGNMENT. */
+ char pad[-6 * SIZE_SZ & MALLOC_ALIGN_MASK];
} heap_info;
/* Get a compile-time error if the heap_info padding is not correct
@@ -692,6 +695,7 @@ new_heap(size, top_pad) size_t size, top_pad;
}
h = (heap_info *)p2;
h->size = size;
+ h->mprotect_size = size;
THREAD_STAT(stat_n_heaps++);
return h;
}
@@ -714,17 +718,34 @@ grow_heap(h, diff) heap_info *h; long diff;
new_size = (long)h->size + diff;
if((unsigned long) new_size > (unsigned long) HEAP_MAX_SIZE)
return -1;
- if(mprotect((char *)h + h->size, diff, PROT_READ|PROT_WRITE) != 0)
- return -2;
+ if((unsigned long) new_size > h->mprotect_size) {
+ if (mprotect((char *)h + h->mprotect_size,
+ (unsigned long) new_size - h->mprotect_size,
+ PROT_READ|PROT_WRITE) != 0)
+ return -2;
+ h->mprotect_size = new_size;
+ }
} else {
new_size = (long)h->size + diff;
if(new_size < (long)sizeof(*h))
return -1;
/* Try to re-map the extra heap space freshly to save memory, and
make it inaccessible. */
- if((char *)MMAP((char *)h + new_size, -diff, PROT_NONE,
- MAP_PRIVATE|MAP_FIXED) == (char *) MAP_FAILED)
- return -2;
+#ifdef _LIBC
+ if (__builtin_expect (__libc_enable_secure, 0))
+#else
+ if (1)
+#endif
+ {
+ if((char *)MMAP((char *)h + new_size, -diff, PROT_NONE,
+ MAP_PRIVATE|MAP_FIXED) == (char *) MAP_FAILED)
+ return -2;
+ h->mprotect_size = new_size;
+ }
+#ifdef _LIBC
+ else
+ madvise ((char *)h + new_size, -diff, MADV_DONTNEED);
+#endif
/*fprintf(stderr, "shrink %p %08lx\n", h, new_size);*/
}
h->size = new_size;