1 files changed, 45 insertions, 0 deletions
diff --git a/bsd-user/bsd-mem.h b/bsd-user/bsd-mem.h
index 0c8d96d9a4..b296c5c6f0 100644
--- a/bsd-user/bsd-mem.h
+++ b/bsd-user/bsd-mem.h
@@ -212,4 +212,49 @@ static inline abi_long do_bsd_mincore(abi_ulong target_addr, abi_ulong len,
     return ret;
 }
 
+/* do_brk() must return target values and target errnos. */
+static inline abi_long do_obreak(abi_ulong brk_val)
+{
+    abi_long mapped_addr;
+    abi_ulong new_brk;
+    abi_ulong old_brk;
+
+    /* brk pointers are always untagged */
+
+    /* do not allow to shrink below initial brk value */
+    if (brk_val < initial_target_brk) {
+        return target_brk;
+    }
+
+    new_brk = TARGET_PAGE_ALIGN(brk_val);
+    old_brk = TARGET_PAGE_ALIGN(target_brk);
+
+    /* new and old target_brk might be on the same page */
+    if (new_brk == old_brk) {
+        target_brk = brk_val;
+        return target_brk;
+    }
+
+    /* Release heap if necesary */
+    if (new_brk < old_brk) {
+        target_munmap(new_brk, old_brk - new_brk);
+
+        target_brk = brk_val;
+        return target_brk;
+    }
+
+    mapped_addr = target_mmap(old_brk, new_brk - old_brk,
+                              PROT_READ | PROT_WRITE,
+                              MAP_FIXED | MAP_EXCL | MAP_ANON | MAP_PRIVATE,
+                              -1, 0);
+
+    if (mapped_addr == old_brk) {
+        target_brk = brk_val;
+        return target_brk;
+    }
+
+    /* For everything else, return the previous break. */
+    return target_brk;
+}
+
 #endif /* BSD_USER_BSD_MEM_H */