From 208fdd64ac908a1f9e259cd7851bedc3915d7e16 Mon Sep 17 00:00:00 2001
From: apio <blobs.trading@gmail.com>
Date: Sat, 8 Apr 2023 12:28:26 +0200
Subject: [PATCH] execvpe: Execute a shell if errno == ENOEXEC

---
 libc/src/unistd.cpp | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/libc/src/unistd.cpp b/libc/src/unistd.cpp
index fba619e9..415e95e8 100644
--- a/libc/src/unistd.cpp
+++ b/libc/src/unistd.cpp
@@ -68,9 +68,21 @@ extern "C"
             int err = errno;
             execve(file.chars(), argv, envp);
 
-            if (errno != ENOENT && errno != EACCES) return -1;
+            if (errno != ENOENT && errno != EACCES && errno != ENOEXEC) return -1;
 
-            // FIXME: POSIX says that if errno == ENOEXEC, we should run /bin/sh <path>.
+            if (errno == ENOEXEC)
+            {
+                Vector<char*> shell_argv;
+                shell_argv.try_append(const_cast<char*>("sh"));
+                char* const* arg = argv;
+                do {
+                    shell_argv.try_append(*arg);
+                } while (*(arg++));
+
+                execve("/bin/sh", shell_argv.data(), envp);
+                errno = ENOEXEC;
+                return -1;
+            }
 
             if (err == EACCES) errno = err;
         }