From c1c5f4f852055bb0b72bd8981c6688a3b0f32b96 Mon Sep 17 00:00:00 2001
From: Emery Hemingway <ehmry@posteo.net>
Date: Mon, 16 Nov 2020 00:38:21 +0100
Subject: [PATCH] genodeSources: patch ld to load read-only segments

---
 packages/genodelabs/default.nix         |  6 +-
 packages/genodelabs/patches/ld-ro.patch | 90 +++++++++++++++++++++++++
 2 files changed, 95 insertions(+), 1 deletion(-)
 create mode 100644 packages/genodelabs/patches/ld-ro.patch

diff --git a/packages/genodelabs/default.nix b/packages/genodelabs/default.nix
index bab5b30..4f25f65 100644
--- a/packages/genodelabs/default.nix
+++ b/packages/genodelabs/default.nix
@@ -296,7 +296,11 @@ let
         '';
     };
 
-  basePatches = [ ./patches/cxx-align.patch ./patches/core-diag.patch ];
+  basePatches = [
+    ./patches/cxx-align.patch
+    ./patches/core-diag.patch
+   ./patches/ld-ro.patch
+  ];
 
 in makePackages // depotPackages // {
 
diff --git a/packages/genodelabs/patches/ld-ro.patch b/packages/genodelabs/patches/ld-ro.patch
new file mode 100644
index 0000000..e5026ca
--- /dev/null
+++ b/packages/genodelabs/patches/ld-ro.patch
@@ -0,0 +1,90 @@
+From 8c4bb7d84838e8c01673caa8ad45a4c042ccdd11 Mon Sep 17 00:00:00 2001
+From: Emery Hemingway <ehmry@posteo.net>
+Date: Mon, 6 Apr 2020 16:32:13 +0530
+Subject: [PATCH] ld: support for loading read-only segments
+
+---
+ repos/base/src/lib/ldso/include/file.h       | 24 ++++++++++++++++++--
+ repos/base/src/lib/ldso/include/region_map.h | 10 ++++++++
+ 2 files changed, 32 insertions(+), 2 deletions(-)
+
+diff --git a/repos/base/src/lib/ldso/include/file.h b/repos/base/src/lib/ldso/include/file.h
+index 1c9ce53ca3..6688f0edd2 100644
+--- a/repos/base/src/lib/ldso/include/file.h
++++ b/repos/base/src/lib/ldso/include/file.h
+@@ -34,6 +34,9 @@ namespace Linker {
+ 
+ 	static inline bool is_rw(Elf::Phdr const &ph) {
+ 		return ((ph.p_flags & PF_MASK) == (PF_R | PF_W)); }
++
++	static inline bool is_ro(Elf::Phdr const &ph) {
++		return ((ph.p_flags & PF_MASK) == PF_R); }
+ }
+ 
+ 
+@@ -280,15 +283,21 @@ struct Linker::Elf_file : File
+ 			else if (is_rw(*ph))
+ 				load_segment_rw(*ph, i);
+ 
++			else if (is_ro(*ph))
++				load_segment_ro(*ph);
++
+ 			else {
+-				error("LD: Non-RW/RX segment");
++				auto X = ph->p_flags & PF_X ? "X" : "-";
++				auto W = ph->p_flags & PF_W ? "W" : "-";
++				auto R = ph->p_flags & PF_R ? "R" : "-";
++				error("LD: unhandled ", X,W,R, " segment at file offset ", Hex(ph->p_offset));
+ 				throw Invalid_file();
+ 			}
+ 		}
+ 	}
+ 
+ 	/**
+-	 * Map read-only segment
++	 * Map read-execute-only segment
+ 	 */
+ 	void load_segment_rx(Elf::Phdr const &p)
+ 	{
+@@ -318,6 +327,17 @@ struct Linker::Elf_file : File
+ 		env.rm().detach(src);
+ 	}
+ 
++	/**
++	 * Map read-only segment
++	 */
++	void load_segment_ro(Elf::Phdr const &p)
++	{
++		Region_map::r()->attach_readonly(rom_cap,
++		                                 trunc_page(p.p_vaddr) + reloc_base,
++		                                 round_page(p.p_memsz),
++		                                 trunc_page(p.p_offset));
++	}
++
+ 	/**
+ 	 * Unmap segements, RM regions, and free allocated dataspaces
+ 	 */
+diff --git a/repos/base/src/lib/ldso/include/region_map.h b/repos/base/src/lib/ldso/include/region_map.h
+index cbee34c639..b30c2221da 100644
+--- a/repos/base/src/lib/ldso/include/region_map.h
++++ b/repos/base/src/lib/ldso/include/region_map.h
+@@ -122,6 +122,16 @@ class Linker::Region_map
+ 				[&] () { _env.upgrade(Parent::Env::pd(), "ram_quota=8K"); });
+ 		}
+ 
++		Local_addr attach_readonly(Dataspace_capability ds, addr_t local_addr,
++		                           size_t size = 0, off_t offset = 0)
++		{
++			return retry<Genode::Out_of_ram>(
++				[&] () {
++					return _rm.attach(ds, size, offset, true, local_addr - _base, false, false);
++				},
++				[&] () { _env.upgrade(Parent::Env::pd(), "ram_quota=8K"); });
++		}
++
+ 		void detach(Local_addr local_addr) { _rm.detach((addr_t)local_addr - _base); }
+ };
+ 
+-- 
+2.28.0
+