From 785752a595ddd382396363f8aa237d1246ed5764 Mon Sep 17 00:00:00 2001
From: Rich Felker <dalias@aerifal.cx>
Date: Mon, 29 Jun 2020 17:41:24 -0400
Subject: add glue code for mallocng merge

this includes both an implementation of reclaimed-gap donation from
ldso and a version of mallocng's glue.h with namespace-safe linkage to
underlying syscalls, integration with AT_RANDOM initialization, and
internal locking that's optimized out when the process is
single-threaded.
---
 src/malloc/mallocng/glue.h | 77 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 77 insertions(+)
 create mode 100644 src/malloc/mallocng/glue.h

(limited to 'src/malloc/mallocng/glue.h')

diff --git a/src/malloc/mallocng/glue.h b/src/malloc/mallocng/glue.h
new file mode 100644
index 00000000..16acd1ea
--- /dev/null
+++ b/src/malloc/mallocng/glue.h
@@ -0,0 +1,77 @@
+#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
-- 
cgit v1.2.1