From f1a150ed430a21b7ca4167c67ff0a6823707fb88 Mon Sep 17 00:00:00 2001
From: Fabian Boehm <FHomborg@gmail.com>
Date: Fri, 30 Dec 2022 11:48:15 +0100
Subject: [PATCH] postfork: Also check if interpreter is a directory

"#!/bin/"
---
 src/postfork.cpp | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/postfork.cpp b/src/postfork.cpp
index 775b45a52..a2884eb33 100644
--- a/src/postfork.cpp
+++ b/src/postfork.cpp
@@ -462,7 +462,9 @@ void safe_report_exec_error(int err, const char *actual_cmd, const char *const *
             char interpreter_buff[128] = {};
             const char *interpreter =
                 get_interpreter(actual_cmd, interpreter_buff, sizeof interpreter_buff);
-            if (interpreter && 0 != access(interpreter, X_OK)) {
+            struct stat buf;
+            auto statret = stat(interpreter, &buf);
+            if (interpreter && (0 != statret || access(interpreter, X_OK))) {
                 // Detect Windows line endings and complain specifically about them.
                 auto len = strlen(interpreter);
                 if (len && interpreter[len - 1] == '\r') {
@@ -477,6 +479,11 @@ void safe_report_exec_error(int err, const char *actual_cmd, const char *const *
                                "executable command.",
                                actual_cmd, interpreter);
                 }
+            } else if (interpreter && S_ISDIR(buf.st_mode)) {
+                FLOGF_SAFE(exec,
+                           "Failed to execute process '%s': The file specified the interpreter "
+                           "'%s', which is a directory.",
+                           actual_cmd, interpreter);
             } else if (access(actual_cmd, X_OK) == 0) {
                 FLOGF_SAFE(exec,
                            "Failed to execute process '%s': The file exists and is executable. "