/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 * Copyright 2022 Spencer Evans-Cole.
 */

#include <stdio.h>
#include <stdio_ext.h>
#include <ctype.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <dirent.h>
#include <errno.h>
#include <sys/types.h>
#include <stropts.h>
#include <poll.h>
#include <procfs.h>
#include <sys/resource.h>

static int count_my_files();
static char *command;

/* slop to account for extra file descriptors opened by libraries we call */
#define	SLOP	5

int
main(int argc, char **argv)
{
	unsigned long remain = 0;
	struct pollfd *pollfd;
	struct pollfd *pfd;
	struct rlimit rlim;
	char *arg;
	unsigned i;
	int verbose = 0;
	pid_t mypid = getpid();

	if ((command = strrchr(argv[0], '/')) != NULL)
		command++;
	else
		command = argv[0];

	argc--;
	argv++;

	if (argc > 0 && strcmp(argv[0], "-v") == 0) {
		verbose = 1;
		argc--;
		argv++;
	}

	if (argc <= 0) {
		(void) fprintf(stderr, "usage:\t%s [-v] pid ...\n", command);
		(void) fprintf(stderr, "  (wait for processes to terminate)\n");
		(void) fprintf(stderr,
		    "  -v: verbose; report terminations to standard out\n");
		return (2);
	}

	/* make sure we have enough file descriptors */
	if (getrlimit(RLIMIT_NOFILE, &rlim) == 0) {
		int nfiles = count_my_files();

		if (rlim.rlim_cur < argc + nfiles + SLOP) {
			rlim.rlim_cur = argc + nfiles + SLOP;
			if (setrlimit(RLIMIT_NOFILE, &rlim) != 0) {
				(void) fprintf(stderr,
				    "%s: insufficient file descriptors\n",
				    command);
				return (2);
			}
		}
		(void) enable_extended_FILE_stdio(-1, -1);
	}

	pollfd = (struct pollfd *)malloc(argc*sizeof (struct pollfd));
	if (pollfd == NULL) {
		perror("malloc");
		return (2);
	}

	for (i = 0; i < argc; i++) {
		char psinfofile[100];

		arg = argv[i];
		if (mypid == atol(arg)) {
			if (verbose) {
				(void) printf("%s: has the same"
				    " pid as this process\n", arg);
			}
			continue;
		}
		if (strchr(arg, '/') != NULL)
			(void) strncpy(psinfofile, arg, sizeof (psinfofile));
		else {
			(void) strcpy(psinfofile, "/proc/");
			(void) strncat(psinfofile, arg, sizeof (psinfofile)-6);
		}
		(void) strncat(psinfofile, "/psinfo",
		    sizeof (psinfofile) - strlen(psinfofile));

		pfd = &pollfd[i];
		if ((pfd->fd = open(psinfofile, O_RDONLY)) >= 0) {
			remain++;
			/*
			 * We set POLLPRI to detect system processes.
			 * We will get POLLNVAL below for a POLLPRI
			 * requested event on a system process.
			 */
			pfd->events = POLLPRI;
			pfd->revents = 0;
		} else if (errno == ENOENT) {
			(void) fprintf(stderr, "%s: no such process: %s\n",
			    command, arg);
		} else {
			perror(arg);
		}
	}

	while (remain != 0) {
		while (poll(pollfd, argc, INFTIM) < 0) {
			if (errno != EAGAIN) {
				perror("poll");
				return (2);
			}
			(void) sleep(2);
		}
		for (i = 0; i < argc; i++) {
			pfd = &pollfd[i];
			if (pfd->fd < 0 || (pfd->revents & ~POLLPRI) == 0) {
				/*
				 * We don't care if a non-system process
				 * stopped.  Don't check for that again.
				 */
				pfd->events = 0;
				pfd->revents = 0;
				continue;
			}

			if (verbose) {
				arg = argv[i];
				if (pfd->revents & POLLHUP) {
					psinfo_t psinfo;

					if (pread(pfd->fd, &psinfo,
					    sizeof (psinfo), (off_t)0)
					    == sizeof (psinfo)) {
						(void) printf("%s: terminated,"
						    " wait status 0x%.4x\n",
						    arg, psinfo.pr_wstat);
					} else {
						(void) printf(
						    "%s: terminated\n", arg);
					}
				}
				if (pfd->revents & POLLNVAL)
					(void) printf("%s: system process\n",
					    arg);
				if (pfd->revents & ~(POLLPRI|POLLHUP|POLLNVAL))
					(void) printf("%s: unknown error\n",
					    arg);
			}

			(void) close(pfd->fd);
			pfd->fd = -1;
			remain--;
		}
	}

	return (0);
}

/* ARGSUSED1 */
static int
do_count(void *nofilesp, int fd)
{
	(*(int *)nofilesp)++;
	return (0);
}

static int
count_my_files()
{
	int nofiles = 0;

	(void) fdwalk(do_count, &nofiles);
	return (nofiles);
}