From 2a3cebdd6e51509f83bcae1f0567d8e67e14efa4 Mon Sep 17 00:00:00 2001
From: Alexander Senier <senier@componolit.com>
Date: Wed, 21 Aug 2019 09:34:35 +0200
Subject: [PATCH] libc: Allow private writable mappings

Fixes #3480
---
 repos/libports/src/lib/libc/vfs_plugin.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/repos/libports/src/lib/libc/vfs_plugin.cc b/repos/libports/src/lib/libc/vfs_plugin.cc
index 9b36f73fb8..6ca429e5c5 100644
--- a/repos/libports/src/lib/libc/vfs_plugin.cc
+++ b/repos/libports/src/lib/libc/vfs_plugin.cc
@@ -1258,7 +1258,7 @@ int Libc::Vfs_plugin::rename(char const *from_path, char const *to_path)
 void *Libc::Vfs_plugin::mmap(void *addr_in, ::size_t length, int prot, int flags,
                              Libc::File_descriptor *fd, ::off_t offset)
 {
-	if (prot != PROT_READ) {
+	if (prot != PROT_READ && !(prot == (PROT_READ | PROT_WRITE) && flags == MAP_PRIVATE)) {
 		Genode::error("mmap for prot=", Genode::Hex(prot), " not supported");
 		errno = EACCES;
 		return (void *)-1;