/*      $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;
}