On Wed, Jun 10, 2009 at 03:04:56PM +1000, Herbert Xu wrote:
> Can you separate these two changes into two patches? It's much
> easier to track down problems if each patch does a single thing.
Bellow are the patches. In the first we can change space[4] also
to space[1]. The second is good for systems which uses malloc
based on mmap and after
void *x = malloc(4000);
free(x);
the region is _unmapped_. One can check this with a simple program
and strace.
diff -urN dash-0.5.5.1_orig/src/memalloc.c dash-0.5.5.1/src/memalloc.c
--- dash-0.5.5.1_orig/src/memalloc.c Wed Jan 14 01:37:13 2009
+++ dash-0.5.5.1/src/memalloc.c Wed Jun 10 09:09:23 2009
@@ -97,18 +97,19 @@
*/
/* minimum size of a block */
-#define MINSIZE SHELL_ALIGN(504)
+/* #define MINSIZE SHELL_ALIGN(504) */
+typedef struct { void *next; size_t size; } __alloc_t;
+#define MINSIZE (512 -SHELL_ALIGN(sizeof(void*) + sizeof(__alloc_t)))
struct stack_block {
struct stack_block *prev;
- char space[MINSIZE];
+ char space[4];
};
-struct stack_block stackbase;
-struct stack_block *stackp = &stackbase;
-char *stacknxt = stackbase.space;
-size_t stacknleft = MINSIZE;
-char *sstrend = stackbase.space + MINSIZE;
+static struct stack_block *stackp = 0;
+char *stacknxt = 0;
+char *sstrend = 0;
+size_t stacknleft = 0;
pointer
stalloc(size_t nbytes)
@@ -125,7 +126,7 @@
blocksize = aligned;
if (blocksize < MINSIZE)
blocksize = MINSIZE;
- len = sizeof(struct stack_block) - MINSIZE + blocksize;
+ len = sizeof(void *) + blocksize;
if (len < blocksize)
sh_error("Out of space");
INTOFF;
@@ -169,7 +170,7 @@
void setstackmark(struct stackmark *mark)
{
- pushstackmark(mark, stacknxt == stackp->space && stackp != &stackbase);
+ pushstackmark(mark, stacknxt == stackp->space);
}
@@ -212,19 +213,13 @@
if (newlen < 128)
newlen += 128;
- if (stacknxt == stackp->space && stackp != &stackbase) {
- struct stack_block *oldstackp;
+ if (stacknxt == stackp->space) {
struct stack_block *sp;
- struct stack_block *prevstackp;
size_t grosslen;
INTOFF;
- oldstackp = stackp;
- sp = stackp;
- prevstackp = sp->prev;
- grosslen = newlen + sizeof(struct stack_block) - MINSIZE;
- sp = ckrealloc((pointer)sp, grosslen);
- sp->prev = prevstackp;
+ grosslen = newlen + sizeof(void *);
+ sp = ckrealloc((pointer)stackp, grosslen);
stackp = sp;
stacknxt = sp->space;
stacknleft = newlen;
===================================================================
diff -urN dash-0.5.5.1_orig/src/memalloc.c dash-0.5.5.1/src/memalloc.c
--- dash-0.5.5.1_orig/src/memalloc.c Wed Jan 14 01:37:13 2009
+++ dash-0.5.5.1/src/memalloc.c Wed Jun 10 09:21:21 2009
@@ -99,6 +99,12 @@
/* minimum size of a block */
#define MINSIZE SHELL_ALIGN(504)
+#if defined(__dietlibc__) || defined(MALLOC_USES_MMAP_FOR_BIG_BLOCKS)
+typedef struct { void *next; size_t size; } __alloc_t;
+#include <sys/shm.h> /* PAGE_SIZE */
+#define XXXSIZE (PAGE_SIZE -SHELL_ALIGN(sizeof(void*) + sizeof(__alloc_t)))
+#endif
+
struct stack_block {
struct stack_block *prev;
char space[MINSIZE];
@@ -123,6 +129,10 @@
struct stack_block *sp;
blocksize = aligned;
+#ifdef XXXSIZE
+ if (stackp && blocksize < XXXSIZE)
+ blocksize = XXXSIZE;
+#endif
if (blocksize < MINSIZE)
blocksize = MINSIZE;
len = sizeof(struct stack_block) - MINSIZE + blocksize;
--
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