From b0ee911c2389e507d36a2f9c2442046133c18b93 Mon Sep 17 00:00:00 2001
From: Jakub Konka <kubkon@jakubkonka.com>
Date: Mon, 7 Jun 2021 18:00:36 +0200
Subject: [PATCH] wasi: always grant fd_readdir right

Since v0.23 release of Wasmtime, if we want to iterate a directory
Y then directory Y needed to have been granted `fd_readdir` right.
However, it is now also required for directory X to carry `fd_readdir`
right, and so on, up-chain all the way until we reach the preopen
(which possesses all rights by default).

This caused problems for us since our libstd implementation is more
fine-grained and allowed for parent dirs not to carry the right while
allow for iterating on its children. My proposal here is to always
grant `fd_readdir` right as part of
`std.fs.Dir.OpenDirOptions.access_sub_paths`. This seems to be the
approach taken by Rust also, plus we should be justified to take this
approach since WASI is experimental and snapshot1 will be discontinued
eventually and replaced with a new approach to access management
that will require a complete rewrite of our libstd anyhow.
---
 ci/azure/linux_script | 6 ++----
 lib/std/fs.zig        | 6 ++----
 test/stage2/wasm.zig  | 8 +-------
 3 files changed, 5 insertions(+), 15 deletions(-)

diff --git a/ci/azure/linux_script b/ci/azure/linux_script
index b740f9d698712e5849fb853dc24899f0a5bb75c2..cf46b2c22210c13949594f1c4d679cd0a8851549 100755
--- a/ci/azure/linux_script
+++ b/ci/azure/linux_script
@@ -25,10 +25,8 @@ wget -nv "https://ziglang.org/deps/$QEMUBASE.tar.xz"
 tar xf "$QEMUBASE.tar.xz"
 export PATH="$(pwd)/$QEMUBASE/bin:$PATH"
 
-# Bump to v0.23 once this issue is resolved:
-# https://github.com/ziglang/zig/issues/8742
-WASMTIME="wasmtime-v0.22.1-x86_64-linux"
-wget -nv "https://github.com/bytecodealliance/wasmtime/releases/download/v0.22.1/$WASMTIME.tar.xz"
+WASMTIME="wasmtime-v0.26.1-x86_64-linux"
+wget -nv "https://github.com/bytecodealliance/wasmtime/releases/download/v0.26.1/$WASMTIME.tar.xz"
 tar xf "$WASMTIME.tar.xz"
 export PATH="$(pwd)/$WASMTIME:$PATH"
 
diff --git a/lib/std/fs.zig b/lib/std/fs.zig
index a280f6ccaaabe0d6fe7c47c19d793f1d01f2fa77..390efec50c7289665e0b8544bb4b86aa158d098f 100644
--- a/lib/std/fs.zig
+++ b/lib/std/fs.zig
@@ -1264,11 +1264,9 @@ pub const Dir = struct {
     pub fn openDirWasi(self: Dir, sub_path: []const u8, args: OpenDirOptions) OpenError!Dir {
         const w = os.wasi;
         var base: w.rights_t = w.RIGHT_FD_FILESTAT_GET | w.RIGHT_FD_FDSTAT_SET_FLAGS | w.RIGHT_FD_FILESTAT_SET_TIMES;
-        if (args.iterate) {
-            base |= w.RIGHT_FD_READDIR;
-        }
         if (args.access_sub_paths) {
-            base |= w.RIGHT_PATH_CREATE_DIRECTORY |
+            base |= w.RIGHT_FD_READDIR |
+                w.RIGHT_PATH_CREATE_DIRECTORY |
                 w.RIGHT_PATH_CREATE_FILE |
                 w.RIGHT_PATH_LINK_SOURCE |
                 w.RIGHT_PATH_LINK_TARGET |
diff --git a/test/stage2/wasm.zig b/test/stage2/wasm.zig
index 828292d2a459be4443e417af96c5d900758a5093..947f90ff0f26f1839ebaa73c637a28492137492b 100644
--- a/test/stage2/wasm.zig
+++ b/test/stage2/wasm.zig
@@ -56,13 +56,7 @@ pub fn addCases(ctx: *TestContext) !void {
             \\}
             \\fn bar() void {}
         ,
-        // This is what you get when you take the bits of the IEE-754
-        // representation of 42.0 and reinterpret them as an unsigned
-        // integer.
-        // Bug is fixed in wasmtime v0.26 but updating to v0.26 is blocked
-        // on this issue:
-        // https://github.com/ziglang/zig/issues/8742
-            "1109917696\n",
+            "42\n",
         );
 
         case.addCompareOutput(
-- 
2.54.0