Get executable name in syscall?

So I am writing a system call in Linux. I want to print a message that looks like

printk(KERN_DEBUG "PROC_DEBUG [%s, %s]: %s", executable, current->pid, message);

Where executable is the name of the executable that is created when I link a source file against the library used to call the syscall. So if I run the command "cc -o sourcefile.c -L ./a -lfilename", is what I want to print for the executable. (The pid is the process ID of the process that is running the executable, and message is a parameter I pass to the system call.) I was trying to use this code to get the executable name

struct task_struct *task = get_current();
char task_com[TASK_COM_LEN];
get_task_com(task_com, task);

But I am getting an error that 'TASK_COM_LEN' is undeclared, so what am I missing? Is there an easier way to get the executable name? Something like "current->executable"? I'm not finding any great matches on the web.