processMonitor.c

#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/sched/signal.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("RYAN WELZEL");
MODULE_DESCRIPTION("Process monitor module");
MODULE_VERSION("1.0");

#define PROC_NAME "processMonitor"

// Writes process info to /proc/ProcessMonitor
// seq_file writes to /proc
static int procmon_show(struct seq_file *m, void *v){
	// Process struct
	struct task_struct *task;

	// Header row for column names
	seq_printf(m, "PID\tPPID\tSTATE\tNAME\n");

	// Disp pid, parent pid, state, name
	for_each_process(task){
		seq_printf(m, "%d\t%d\t%u\t%s\n",
		task->pid,
		task_ppid_nr(task),
		READ_ONCE(task->__state),
		task->comm);
	}

	return 0;
}

// Set up seq_file context
static int procmon_open(struct inode *inode, struct file *file){
	return single_open(file, procmon_show, NULL);
}

// On cat /proc/ProcessMonitor call procmon_open
// Other params default
static const struct proc_ops proc_file_ops = {
	.proc_open = procmon_open,
	.proc_read = seq_read,
	.proc_lseek = seq_lseek,
	.proc_release = single_release,

};

static int __init procmon_init(void){
	proc_create(PROC_NAME, 0, NULL, &proc_file_ops);
	return 0;
}

static void __exit procmon_exit(void){
	remove_proc_entry(PROC_NAME, NULL);
}

module_init(procmon_init);
module_exit(procmon_exit);