kern/user/progS.c

#include <common.h>

/**
** User function S:   exit, sleep, write
**
** Reports itself, then loops forever, sleeping on each iteration
**
** Invoked as:  userS  x  [ s ]
**	 where x is the ID character
**		   s is the sleep time (defaults to 20)
*/

USERMAIN(main)
{
	char ch = 's'; // default character to print
	int nap = 20; // nap time
	char buf[128];

	// process the command-line arguments
	switch (argc) {
	case 3:
		nap = str2int(argv[2], 10);
		// FALL THROUGH
	case 2:
		ch = argv[1][0];
		break;
	default:
		sprint(buf, "userS: argc %d, args: ", argc);
		cwrites(buf);
		for (int i = 0; i <= argc; ++i) {
			sprint(buf, " %s", argv[argc] ? argv[argc] : "(null)");
			cwrites(buf);
		}
		cwrites("\n");
	}

	// announce our presence
	write(CHAN_SIO, &ch, 1);

	sprint(buf, "userS sleeping %d(%d)\n", nap, SEC_TO_MS(nap));
	cwrites(buf);

	for (;;) {
		sleep(SEC_TO_MS(nap));
		write(CHAN_SIO, &ch, 1);
	}

	sprint(buf, "!! %c exiting!?!?!?\n", ch);
	cwrites(buf);
	exit(1);

	return (42); // shut the compiler up!
}