1 files changed, 102 insertions, 0 deletions
diff --git a/library/std/src/sys/env/sgx.rs b/library/std/src/sys/env/sgx.rs
new file mode 100644
index 00000000000..7a48fb1872b
--- /dev/null
+++ b/library/std/src/sys/env/sgx.rs
@@ -0,0 +1,102 @@
+#![allow(fuzzy_provenance_casts)] // FIXME: this module systematically confuses pointers and integers
+
+use crate::collections::HashMap;
+use crate::ffi::{OsStr, OsString};
+use crate::sync::atomic::{AtomicUsize, Ordering};
+use crate::sync::{Mutex, Once};
+use crate::{fmt, io, vec};
+
+// Specifying linkage/symbol name is solely to ensure a single instance between this crate and its unit tests
+#[cfg_attr(test, linkage = "available_externally")]
+#[unsafe(export_name = "_ZN16__rust_internals3std3sys3pal3sgx2os3ENVE")]
+static ENV: AtomicUsize = AtomicUsize::new(0);
+// Specifying linkage/symbol name is solely to ensure a single instance between this crate and its unit tests
+#[cfg_attr(test, linkage = "available_externally")]
+#[unsafe(export_name = "_ZN16__rust_internals3std3sys3pal3sgx2os8ENV_INITE")]
+static ENV_INIT: Once = Once::new();
+type EnvStore = Mutex<HashMap<OsString, OsString>>;
+
+fn get_env_store() -> Option<&'static EnvStore> {
+    unsafe { (ENV.load(Ordering::Relaxed) as *const EnvStore).as_ref() }
+}
+
+fn create_env_store() -> &'static EnvStore {
+    ENV_INIT.call_once(|| {
+        ENV.store(Box::into_raw(Box::new(EnvStore::default())) as _, Ordering::Relaxed)
+    });
+    unsafe { &*(ENV.load(Ordering::Relaxed) as *const EnvStore) }
+}
+
+pub struct Env {
+    iter: vec::IntoIter<(OsString, OsString)>,
+}
+
+// FIXME(https://github.com/rust-lang/rust/issues/114583): Remove this when <OsStr as Debug>::fmt matches <str as Debug>::fmt.
+pub struct EnvStrDebug<'a> {
+    slice: &'a [(OsString, OsString)],
+}
+
+impl fmt::Debug for EnvStrDebug<'_> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let Self { slice } = self;
+        f.debug_list()
+            .entries(slice.iter().map(|(a, b)| (a.to_str().unwrap(), b.to_str().unwrap())))
+            .finish()
+    }
+}
+
+impl Env {
+    pub fn str_debug(&self) -> impl fmt::Debug + '_ {
+        let Self { iter } = self;
+        EnvStrDebug { slice: iter.as_slice() }
+    }
+}
+
+impl fmt::Debug for Env {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let Self { iter } = self;
+        f.debug_list().entries(iter.as_slice()).finish()
+    }
+}
+
+impl !Send for Env {}
+impl !Sync for Env {}
+
+impl Iterator for Env {
+    type Item = (OsString, OsString);
+    fn next(&mut self) -> Option<(OsString, OsString)> {
+        self.iter.next()
+    }
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.iter.size_hint()
+    }
+}
+
+pub fn env() -> Env {
+    let clone_to_vec = |map: &HashMap<OsString, OsString>| -> Vec<_> {
+        map.iter().map(|(k, v)| (k.clone(), v.clone())).collect()
+    };
+
+    let iter = get_env_store()
+        .map(|env| clone_to_vec(&env.lock().unwrap()))
+        .unwrap_or_default()
+        .into_iter();
+    Env { iter }
+}
+
+pub fn getenv(k: &OsStr) -> Option<OsString> {
+    get_env_store().and_then(|s| s.lock().unwrap().get(k).cloned())
+}
+
+pub unsafe fn setenv(k: &OsStr, v: &OsStr) -> io::Result<()> {
+    let (k, v) = (k.to_owned(), v.to_owned());
+    create_env_store().lock().unwrap().insert(k, v);
+    Ok(())
+}
+
+pub unsafe fn unsetenv(k: &OsStr) -> io::Result<()> {
+    if let Some(env) = get_env_store() {
+        env.lock().unwrap().remove(k);
+    }
+    Ok(())
+}