/*      $NetBSD: gcore.c,v 1.12 2019/02/01 08:29:04 mrg Exp $   */

/*-
 * Copyright (c) 2003 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Christos Zoulas.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

#include <sys/cdefs.h>
__RCSID("$NetBSD: gcore.c,v 1.12 2019/02/01 08:29:04 mrg Exp $");

#include <sys/types.h>
#include <sys/param.h>
#include <sys/time.h>
#include <sys/ptrace.h>
#include <sys/proc.h>
#include <sys/wait.h>

#include <stdio.h>
#include <string.h>
#include <err.h>
#include <limits.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>

static void usage(void) __dead;

static void
usage(void)
{
        (void)fprintf(stderr, "Usage: %s [-c <corename>] <pid> [<pid> ...]\n",
            getprogname());
        exit(1);
}


int
main(int argc, char **argv)
{
        int c;
        char *corename = NULL;
        int corelen = 0;

        while ((c = getopt(argc, argv, "c:")) != -1)
                switch (c) {
                case 'c':
                        corename = optarg;
                        corelen = strlen(corename);
                        break;
                case '?':
                default:
                        usage();
                        /*NOTREACHED*/
                }

        if (optind == argc)
                usage();

        for (c = optind; c < argc; c++) {
                char *ep;
                u_long lval;
                int status, serrno;
                pid_t pid, cpid;

                errno = 0;
                lval = strtoul(argv[c], &ep, 0);
                if (argv[c] == NULL || *ep)
                        errx(1, "`%s' is not a number.", argv[c]);

                if (errno == ERANGE && lval == ULONG_MAX)
                        err(1, "Pid `%s'", argv[c]);

                pid = (pid_t)lval;

                if (ptrace(PT_ATTACH, pid, 0, 0) == -1)
                        err(1, "ptrace(PT_ATTACH) to %lu failed", lval);

                if ((cpid = waitpid(pid, &status, 0)) != pid) {
                        serrno = errno;
                        (void)ptrace(PT_DETACH, pid, (void *)1, 0);
                        errno = serrno;
                        if (cpid == -1)
                                err(1, "Cannot wait for %lu", lval);
                        else
                                errx(1, "Unexpected process %lu waited",
                                    (unsigned long)cpid);
                }

                if (ptrace(PT_DUMPCORE, pid, corename, corelen) == -1) {
                        serrno = errno;
                        (void)ptrace(PT_DETACH, pid, (void *)1, 0);
                        errno = serrno;
                        err(1, "ptrace(PT_DUMPCORE) to %lu failed", lval);
                }
                if (ptrace(PT_DETACH, pid, (void *)1, 0) == -1)
                        err(1, "ptrace(PT_DETACH) to %lu failed", lval);
        }
        return 0;
}