/*
 * Print out the process command name for this process's ancestors,
 * up to init.
 *
 * Dan Cross <net!gajendra!cross>
 */

#include <sys/types.h>
#include <sys/param.h>
#include <sys/sysctl.h>

#include <fcntl.h>
#include <kvm.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

kvm_t *kd;

struct kinfo_proc *
getparent(pid_t pid)
{
	int c;
	struct kinfo_proc *r;

	c = 0;
	r = kvm_getprocs(kd, KERN_PROC_PID, (int)pid, sizeof(*r), &c);
	if (c != 1)
		return(NULL);
	return r;
}

void
uptoinit(pid_t startpid, int printpid)
{
	pid_t pid, ppid;
	struct kinfo_proc *proc;

	ppid = startpid;
	do {
		pid = ppid;
		proc = getparent(pid);
		if (proc == NULL) {
			perror("getparent");
			kvm_close(kd);
			exit(EXIT_FAILURE);
		}
		if (printpid)
			printf("%d ", (int)pid);
		printf("%s\n", proc->p_comm);
		ppid = proc->p_ppid;
	} while (ppid != pid && ppid != 0);
}

int
main(int argc, char *argv[])
{
	pid_t pid;
	int printpid, ch;

	printpid = 0;
	pid = getpid();
	while ((ch = getopt(argc, argv, "ph?")) != -1)
		switch (ch) {
		case 'p':
			printpid = 1;
			break;
		case 'h':
		case '?':
		default:
			fprintf(stderr, "Usage: %s [ -p ] [ pid[s] ]\n", argv[0]);
			return(EXIT_FAILURE);
			break;	/* NOTREACHED */
		}
	argc -= optind;
	argv += optind;
	kd = kvm_open(NULL, NULL, NULL, O_RDONLY, "kvm_open");
	if (kd == NULL)
		return(EXIT_FAILURE);
	if (argc == 0)
		uptoinit(getpid(), printpid);
	else while (*argv != NULL) {
		pid = atoi(*argv++);
		uptoinit(pid, printpid);
	}
	kvm_close(kd);

	return(EXIT_SUCCESS);
}