libc: Fix execvp() calling the shell after an ENOEXEC

apps/sh.cpp

@@ -23,6 +23,8 @@ static Result<Vector<String>> split_command_into_args(StringView cmd)
 
 static Result<void> execute_command(StringView command)
 {
+    if (strcspn(command.chars(), " #") == 0) return {};
+
     auto args = TRY(split_command_into_args(command));
     if (args.size() < 1) exit(0);
 
@@ -94,6 +96,8 @@ Result<int> luna_main(int argc, char** argv)
 
         if (strspn(cmd.chars(), " \n") == cmd.length()) continue;
 
+        if (strcspn(cmd.chars(), " #") == 0) continue;
+
         if (!strncmp(cmd.chars(), "cd", 2))
         {
             auto args = TRY(split_command_into_args(cmd.view()));

initrd/sbin/mount-tmpfs

@@ -1,3 +1,5 @@
+#!/bin/sh
+
 mkdir -p /tmp
 mount -t tmpfs /tmp
 chmod 1777 /tmp

libc/src/unistd.cpp

@@ -42,7 +42,8 @@ static Result<int> try_execvpe(const char* name, char* const* argv, char* const*
         {
             Vector<char*> shell_argv;
             TRY(shell_argv.try_append(const_cast<char*>("sh")));
-            char* const* arg = argv;
+            TRY(shell_argv.try_append(file.mutable_data()));
+            char* const* arg = argv + 1;
             do {
                 TRY(shell_argv.try_append(*arg));
             } while (*(arg++));