From fa4b1c401da1ac381d4d72172825231b3d5518d9 Mon Sep 17 00:00:00 2001
From: Aliaksey Kandratsenka <alk@tut.by>
Date: Sun, 19 Jan 2014 22:37:44 -0800
Subject: [PATCH] issue-599: fixing FreeBSD issue with sbrk

Applied patch by yurivict.

It was wrong assembly specifically for FreeBSD in sbrk overriding
code.
---
 src/malloc_hook_mmap_freebsd.h | 41 +++++-----------------------------
 1 file changed, 5 insertions(+), 36 deletions(-)

diff --git a/src/malloc_hook_mmap_freebsd.h b/src/malloc_hook_mmap_freebsd.h
index ee62eec..8575dcc 100644
--- a/src/malloc_hook_mmap_freebsd.h
+++ b/src/malloc_hook_mmap_freebsd.h
@@ -40,6 +40,7 @@
 #include <sys/syscall.h>
 #include <sys/mman.h>
 #include <errno.h>
+#include <dlfcn.h>
 
 // Make sure mmap doesn't get #define'd away by <sys/mman.h>
 #undef mmap
@@ -74,43 +75,11 @@ static inline void* do_mmap(void *start, size_t length,
 }
 
 static inline void* do_sbrk(intptr_t increment) {
-  void* curbrk = 0;
+  static void *(*libc_sbrk)(intptr_t);
+  if (libc_sbrk == NULL)
+    libc_sbrk = (void *(*)(intptr_t))dlsym(RTLD_NEXT, "sbrk");
 
-#if defined(__x86_64__) || defined(__amd64__)
-# ifdef PIC
-  __asm__ __volatile__(
-      "movq .curbrk@GOTPCREL(%%rip), %%rdx;"
-      "movq (%%rdx), %%rax;"
-      "movq %%rax, %0;"
-      : "=r" (curbrk)
-      :: "%rdx", "%rax");
-# else
-  __asm__ __volatile__(
-      "movq .curbrk(%%rip), %%rax;"
-      "movq %%rax, %0;"
-      : "=r" (curbrk)
-      :: "%rax");
-# endif
-#else
-  __asm__ __volatile__(
-      "movl .curbrk, %%eax;"
-      "movl %%eax, %0;"
-      : "=r" (curbrk)
-      :: "%eax");
-#endif
-
-  if (increment == 0) {
-    return curbrk;
-  }
-
-  char* prevbrk = static_cast<char*>(curbrk);
-  void* newbrk = prevbrk + increment;
-
-  if (brk(newbrk) == -1) {
-    return reinterpret_cast<void*>(static_cast<intptr_t>(-1));
-  }
-
-  return prevbrk;
+  return libc_sbrk(increment);
 }