/*-
 * Copyright (c) 1992, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * @(#) Copyright (c) 1992, 1993 The Regents of the University of California.  All rights reserved.
 * @(#)gcore.c	8.2 (Berkeley) 9/23/93
 * $FreeBSD: src/usr.bin/gcore/gcore.c,v 1.15.2.2 2001/08/17 20:56:22 mikeh Exp $
 * $DragonFly: src/usr.bin/gcore/gcore.c,v 1.11 2007/02/25 23:07:08 corecode Exp $
 */

/*
 * Originally written by Eric Cooper in Fall 1981.
 * Inspired by a version 6 program by Len Levin, 1978.
 * Several pieces of code lifted from Bill Joy's 4BSD ps.
 * Most recently, hacked beyond recognition for 4.4BSD by Steven McCanne,
 * Lawrence Berkeley Laboratory.
 *
 * Portions of this software were developed by the Computer Systems
 * Engineering group at Lawrence Berkeley Laboratory under DARPA
 * contract BG 91-66 and contributed to Berkeley.
 */
#include <sys/param.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <sys/user.h>
#include <sys/sysctl.h>
#include <machine/elf.h>

#include <machine/vmparam.h>

#include <a.out.h>
#include <err.h>
#include <fcntl.h>
#include <kvm.h>
#include <limits.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "extern.h"

static void	killed(int);
static void	restart_target(void);
static void	usage(void) __dead2;

kvm_t *kd;

static pid_t pid;

int
main(int argc, char **argv)
{
	struct exec exec;
	int ch, cnt, efd, fd, sflag;
	char *binfile, *corefile;
	char fname[MAXPATHLEN + 1];

	sflag = 0;
	corefile = NULL;
        while ((ch = getopt(argc, argv, "c:s")) != -1) {
                switch (ch) {
                case 'c':
			corefile = optarg;
                        break;
		case 's':
			sflag = 1;
			break;
		default:
			usage();
			break;
		}
	}
	argv += optind;
	argc -= optind;

	/* XXX we should check that the pid argument is really a number */
	switch (argc) {
	case 1:
		pid = atoi(argv[0]);
		asprintf(&binfile, "/proc/%d/file", pid);
		if (binfile == NULL)
			errx(1, "allocation failure");
		break;
	case 2:
		pid = atoi(argv[1]);
		binfile = argv[0];
		break;
	default:
		usage();
	}

	efd = open(binfile, O_RDONLY, 0);
	if (efd < 0)
		err(1, "%s", binfile);

	cnt = read(efd, &exec, sizeof(exec));
	if (cnt != sizeof(exec))
		errx(1, "%s exec header: %s",
		    binfile, cnt > 0 ? strerror(EIO) : strerror(errno));
	if (IS_ELF(*(Elf_Ehdr *)&exec)) {
		close(efd);
	} else
		errx(1, "Invalid executable file");

	if (corefile == NULL) {
		(void)snprintf(fname, sizeof(fname), "core.%d", pid);
		corefile = fname;
	}
	fd = open(corefile, O_RDWR|O_CREAT|O_TRUNC, DEFFILEMODE);
	if (fd < 0)
		err(1, "%s", corefile);

	if (sflag) {
		signal(SIGHUP, killed);
		signal(SIGINT, killed);
		signal(SIGTERM, killed);
		if (kill(pid, SIGSTOP) == -1)
			err(1, "%d: stop signal", pid);
		atexit(restart_target);
	}

	elf_coredump(fd, pid);

	(void)close(fd);
	exit(0);
}

static void
killed(int sig)
{
	restart_target();
	signal(sig, SIG_DFL);
	kill(getpid(), sig);
}

static void
restart_target(void)
{
	kill(pid, SIGCONT);
}

void
usage(void)
{
	(void)fprintf(stderr, "usage: gcore [-s] [-c core] [executable] pid\n");
	exit(1);
}