config is lazy_static to amoritze it

crates/test-programs/wasi-tests/Cargo.lock

@@ -1,5 +1,11 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
+[[package]]
+name = "lazy_static"
+version = "1.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
+
 [[package]]
 name = "libc"
 version = "0.2.72"
@@ -22,6 +28,7 @@ checksum = "fd6fbd9a79829dd1ad0cc20627bf1ed606756a7f77edff7b66b7064f9cb327c6"
 name = "wasi-tests"
 version = "0.19.0"
 dependencies = [
+ "lazy_static",
  "libc",
  "more-asserts",
  "wasi",

crates/test-programs/wasi-tests/Cargo.toml

@@ -10,6 +10,7 @@ publish = false
 libc = "0.2.65"
 wasi = "0.10.2"
 more-asserts = "0.2.1"
+lazy_static = "1.4"
 
 # This crate is built with the wasm32-wasi target, so it's separate
 # from the main Wasmtime build, so use this directive to exclude it

crates/test-programs/wasi-tests/src/config.rs

@@ -0,0 +1,48 @@
+pub struct TestConfig {
+    errno_mode: ErrnoMode,
+    no_dangling_symlinks: bool,
+    no_fd_allocate: bool,
+}
+
+enum ErrnoMode {
+    Linux,
+    Windows,
+    Permissive,
+}
+
+impl TestConfig {
+    pub fn from_env() -> Self {
+        let errno_mode = if std::env::var("ERRNO_MODE_LINUX").is_ok() {
+            ErrnoMode::Linux
+        } else if std::env::var("ERRNO_MODE_WINDOWS").is_ok() {
+            ErrnoMode::Windows
+        } else {
+            ErrnoMode::Permissive
+        };
+        let no_dangling_symlinks = std::env::var("NO_DANGLING_SYMLINKS").is_ok();
+        let no_fd_allocate = std::env::var("NO_FD_ALLOCATE").is_ok();
+        TestConfig {
+            errno_mode,
+            no_dangling_symlinks,
+            no_fd_allocate,
+        }
+    }
+    pub fn errno_expect_linux(&self) -> bool {
+        match self.errno_mode {
+            ErrnoMode::Linux => true,
+            _ => false,
+        }
+    }
+    pub fn errno_expect_windows(&self) -> bool {
+        match self.errno_mode {
+            ErrnoMode::Windows => true,
+            _ => false,
+        }
+    }
+    pub fn support_dangling_symlinks(&self) -> bool {
+        !self.no_dangling_symlinks
+    }
+    pub fn support_fd_allocate(&self) -> bool {
+        !self.no_fd_allocate
+    }
+}

crates/test-programs/wasi-tests/src/lib.rs

@@ -1,4 +1,9 @@
 use more_asserts::assert_gt;
+pub mod config;
+
+lazy_static::lazy_static! {
+    pub static ref TESTCONFIG: config::TestConfig = config::TestConfig::from_env();
+}
 
 // The `wasi` crate version 0.9.0 and beyond, doesn't
 // seem to define these constants, so we do it ourselves.
@@ -69,7 +74,7 @@ macro_rules! assert_errno {
     };
     ($s:expr, windows => $i:expr, $( $rest:expr ),+) => {
         let e = $s;
-        if std::env::var("ERRNO_EXPECT_WINDOWS").is_ok() {
+        if $crate::TESTCONFIG.errno_expect_windows() {
             assert_errno!(e, $i);
         } else {
             assert_errno!(e, $($rest),+, $i);
@@ -77,7 +82,7 @@ macro_rules! assert_errno {
     };
     ($s:expr, linux => $i:expr, $( $rest:expr ),+) => {
         let e = $s;
-        if std::env::var("ERRNO_EXPECT_LINUX").is_ok() {
+        if $crate::TESTCONFIG.errno_expect_linux() {
             assert_errno!(e, $i);
         } else {
             assert_errno!(e, $($rest),+, $i);