From a32e26b8e9987177ef7573594b2aab2104ca9d3f Mon Sep 17 00:00:00 2001
From: Daniel Micay <danielmicay@gmail.com>
Date: Fri, 5 Jul 2019 21:59:44 -0400
Subject: [PATCH] avoid trying to use mremap outside of Linux

---
 h_malloc.c | 2 ++
 memory.c   | 2 ++
 memory.h   | 6 ++++++
 3 files changed, 10 insertions(+)

diff --git a/h_malloc.c b/h_malloc.c
index 29187bf..e8ffb4f 100644
--- a/h_malloc.c
+++ b/h_malloc.c
@@ -1416,6 +1416,7 @@ EXPORT void *h_realloc(void *old, size_t size) {
                 return old;
             }
 
+#ifdef HAVE_COMPATIBLE_MREMAP
             static const bool vma_merging_reliable = false;
             if (vma_merging_reliable) {
                 // in-place growth
@@ -1465,6 +1466,7 @@ EXPORT void *h_realloc(void *old, size_t size) {
                 thread_seal_metadata();
                 return new;
             }
+#endif
         }
     }
 
diff --git a/memory.c b/memory.c
index f0020a3..7c5abb3 100644
--- a/memory.c
+++ b/memory.c
@@ -68,6 +68,7 @@ int memory_protect_rw_metadata(void *ptr, size_t size) {
     return memory_protect_prot(ptr, size, PROT_READ|PROT_WRITE, get_metadata_key());
 }
 
+#ifdef HAVE_COMPATIBLE_MREMAP
 int memory_remap(void *old, size_t old_size, size_t new_size) {
     void *ptr = mremap(old, old_size, new_size, 0);
     if (unlikely(ptr == MAP_FAILED)) {
@@ -89,6 +90,7 @@ int memory_remap_fixed(void *old, size_t old_size, void *new, size_t new_size) {
     }
     return 0;
 }
+#endif
 
 void memory_set_name(UNUSED void *ptr, UNUSED size_t size, UNUSED const char *name) {
 #ifdef LABEL_MEMORY
diff --git a/memory.h b/memory.h
index 3a6decd..fe51546 100644
--- a/memory.h
+++ b/memory.h
@@ -3,6 +3,10 @@
 
 #include <stddef.h>
 
+#ifdef __linux__
+#define HAVE_COMPATIBLE_MREMAP
+#endif
+
 int get_metadata_key(void);
 
 void *memory_map(size_t size);
@@ -11,8 +15,10 @@ int memory_unmap(void *ptr, size_t size);
 int memory_protect_ro(void *ptr, size_t size);
 int memory_protect_rw(void *ptr, size_t size);
 int memory_protect_rw_metadata(void *ptr, size_t size);
+#ifdef HAVE_COMPATIBLE_MREMAP
 int memory_remap(void *old, size_t old_size, size_t new_size);
 int memory_remap_fixed(void *old, size_t old_size, void *new, size_t new_size);
+#endif
 void memory_set_name(void *ptr, size_t size, const char *name);
 
 #endif