From f474f3d6689ed013ef1753d8b40c5cc967b1db42 Mon Sep 17 00:00:00 2001
From: zoraaver <55952569+zoraaver@users.noreply.github.com>
Date: Mon, 25 Sep 2023 11:40:12 +0100
Subject: [PATCH] Return __WASI_EINVAL from fd_prestat_dir_name (#2580)

Return a WASI error code (rather than a host POSIX one). In addition,
there is no need to return an error in the case that the provided buffer
is too large.
---
 .../libc-wasi/sandboxed-system-primitives/src/posix.c     | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/core/iwasm/libraries/libc-wasi/sandboxed-system-primitives/src/posix.c b/core/iwasm/libraries/libc-wasi/sandboxed-system-primitives/src/posix.c
index bb6d67a6..fc6bc283 100644
--- a/core/iwasm/libraries/libc-wasi/sandboxed-system-primitives/src/posix.c
+++ b/core/iwasm/libraries/libc-wasi/sandboxed-system-primitives/src/posix.c
@@ -819,12 +819,14 @@ wasmtime_ssp_fd_prestat_dir_name(struct fd_prestats *prestats, __wasi_fd_t fd,
         rwlock_unlock(&prestats->lock);
         return error;
     }
-    if (path_len != strlen(prestat->dir)) {
+
+    const size_t prestat_dir_len = strlen(prestat->dir);
+    if (path_len < prestat_dir_len) {
         rwlock_unlock(&prestats->lock);
-        return EINVAL;
+        return __WASI_EINVAL;
     }
 
-    bh_memcpy_s(path, (uint32)path_len, prestat->dir, (uint32)path_len);
+    bh_memcpy_s(path, (uint32)path_len, prestat->dir, (uint32)prestat_dir_len);
 
     rwlock_unlock(&prestats->lock);