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From: Rich Felker <dalias@libc.org>
To: musl@lists.openwall.com
Subject: Re: [musl] mallocng switchover - opportunity to test
Date: Thu, 11 Jun 2020 00:33:02 -0400	[thread overview]
Message-ID: <20200611043301.GM1079@brightrain.aerifal.cx> (raw)
In-Reply-To: <20200611034934.GL1079@brightrain.aerifal.cx>

[-- Attachment #1: Type: text/plain, Size: 1543 bytes --]

On Wed, Jun 10, 2020 at 11:49:34PM -0400, Rich Felker wrote:
> On Mon, Jun 08, 2020 at 11:50:10PM -0400, Rich Felker wrote:
> > I just pushed a series of changes in preparation for upstreaming
> > mallocng. Before it's actually imported, it can be tested by
> > performing the following simple 4 steps:
> > 
> > 1. mkdir src/malloc/mallocng
> > 2. echo "MALLOC_DIR = mallocng" >> config.mak
> > 3. Dropping the attached files into src/malloc/mallocng
> > 4. Symlinking or copying meta.h, malloc.c, realloc.c, free.c,
> >    malloc_usable_size.c, and aligned_alloc.c from mallocng source dir
> >    to src/malloc/mallocng. (You can also include dump.c if desired.)
> > 
> > This produces a near-fully-integrated malloc, including support for
> > reclaim_gaps donation from ldso. The only functionality missing, which
> > I expect to flesh out before actual import, is handling of the case of
> > incomplete malloc replacement by interposition (__malloc_replaced!=0).
> > 
> > Please report any problems encountered.
> 
> For reference -- I should have mentioned in the original post -- the
> above is with musl commit 384c0131ccda2656dec23a0416ad3f14101151a7
> and mallocng-draft commit c0d6d87596f565e652e126f54aa1a2afaecc0e52.
> 
> I'll have an update to these posted soon.

Updated upsteam. Reduction in what's needed to integrate, only 2 files
now, smaller than before (attached).

musl: ca36573ecf
mallocng-draft: 55c1e76bb0

Files needed from mallocng: meta.h, malloc.c, realloc.c, free.c,
malloc_usable_size.c, and aligned_alloc.c

Rich

[-- Attachment #2: glue.h --]
[-- Type: text/plain, Size: 1518 bytes --]

#ifndef MALLOC_GLUE_H
#define MALLOC_GLUE_H

#include <stdint.h>
#include <sys/mman.h>
#include <pthread.h>
#include <unistd.h>
#include <elf.h>
#include <string.h>
#include "atomic.h"
#include "syscall.h"
#include "libc.h"
#include "lock.h"
#include "dynlink.h"

// use macros to appropriately namespace these.
#define size_classes __malloc_size_classes
#define ctx __malloc_context
#define alloc_meta __malloc_alloc_meta
#define is_allzero __malloc_allzerop
#define dump_heap __dump_heap

#if USE_REAL_ASSERT
#include <assert.h>
#else
#undef assert
#define assert(x) do { if (!(x)) a_crash(); } while(0)
#endif

#define brk(p) ((uintptr_t)__syscall(SYS_brk, p))

#define mmap __mmap
#define madvise __madvise
#define mremap __mremap

#define DISABLE_ALIGNED_ALLOC (__malloc_replaced && !__aligned_alloc_replaced)

static inline uint64_t get_random_secret()
{
	uint64_t secret = (uintptr_t)&secret * 1103515245;
	for (size_t i=0; libc.auxv[i]; i+=2)
		if (libc.auxv[i]==AT_RANDOM)
			memcpy(&secret, (char *)libc.auxv[i+1]+8, sizeof secret);
	return secret;
}

#ifndef PAGESIZE
#define PAGESIZE PAGE_SIZE
#endif

#define MT (libc.need_locks)

#define RDLOCK_IS_EXCLUSIVE 1

__attribute__((__visibility__("hidden")))
extern int __malloc_lock[1];

#define LOCK_OBJ_DEF \
int __malloc_lock[1];

static inline void rdlock()
{
	if (MT) LOCK(__malloc_lock);
}
static inline void wrlock()
{
	if (MT) LOCK(__malloc_lock);
}
static inline void unlock()
{
	UNLOCK(__malloc_lock);
}
static inline void upgradelock()
{
}

#endif

[-- Attachment #3: donate.c --]
[-- Type: text/plain, Size: 881 bytes --]

#include <stdlib.h>
#include <stdint.h>
#include <limits.h>
#include <string.h>
#include <sys/mman.h>
#include <errno.h>

#include "meta.h"

static void donate(unsigned char *base, size_t len)
{
	uintptr_t a = (uintptr_t)base;
	uintptr_t b = a + len;
	a += -a & (UNIT-1);
	b -= b & (UNIT-1);
	memset(base, 0, len);
	for (int sc=47; sc>0 && b>a; sc-=4) {
		if (b-a < (size_classes[sc]+1)*UNIT) continue;
		struct meta *m = alloc_meta();
		m->avail_mask = 0;
		m->freed_mask = 1;
		m->mem = (void *)a;
		m->mem->meta = m;
		m->last_idx = 0;
		m->freeable = 0;
		m->sizeclass = sc;
		m->maplen = 0;
		*((unsigned char *)m->mem+UNIT-4) = 0;
		*((unsigned char *)m->mem+UNIT-3) = 255;
		m->mem->storage[size_classes[sc]*UNIT-4] = 0;
		queue(&ctx.active[sc], m);
		a += (size_classes[sc]+1)*UNIT;
	}
}

void __malloc_donate(char *start, char *end)
{
	donate((void *)start, end-start);
}

      reply	other threads:[~2020-06-11  4:33 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-09  3:50 Rich Felker
2020-06-09 11:09 ` Szabolcs Nagy
2020-06-09 20:08   ` Rich Felker
2020-06-10  0:58     ` Rich Felker
2020-06-10  8:33       ` Szabolcs Nagy
2020-06-11 20:05         ` Rich Felker
2020-06-12 17:42           ` Szabolcs Nagy
2020-06-10  9:19     ` Szabolcs Nagy
2020-06-10 16:41       ` Rich Felker
2020-06-11  3:49 ` Rich Felker
2020-06-11  4:33   ` Rich Felker [this message]

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