usr.bin/gcore/gcore.c

   1 /*-
   2  * Copyright (c) 1992, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  * @(#) Copyright (c) 1992, 1993 The Regents of the University of California.  All rights reserved.
  30  * @(#)gcore.c  8.2 (Berkeley) 9/23/93
  31  * $FreeBSD: src/usr.bin/gcore/gcore.c,v 1.15.2.2 2001/08/17 20:56:22 mikeh Exp $
  32  * $DragonFly: src/usr.bin/gcore/gcore.c,v 1.11 2007/02/25 23:07:08 corecode Exp $
  33  */
  34
  35 /*
  36  * Originally written by Eric Cooper in Fall 1981.
  37  * Inspired by a version 6 program by Len Levin, 1978.
  38  * Several pieces of code lifted from Bill Joy's 4BSD ps.
  39  * Most recently, hacked beyond recognition for 4.4BSD by Steven McCanne,
  40  * Lawrence Berkeley Laboratory.
  41  *
  42  * Portions of this software were developed by the Computer Systems
  43  * Engineering group at Lawrence Berkeley Laboratory under DARPA
  44  * contract BG 91-66 and contributed to Berkeley.
  45  */
  46 #include <sys/user.h>
  47 #include <sys/param.h>
  48 #include <sys/time.h>
  49 #include <sys/stat.h>
  50 #include <sys/sysctl.h>
  51 #include <machine/elf.h>
  52
  53 #include <machine/vmparam.h>
  54
  55 #include <a.out.h>
  56 #include <err.h>
  57 #include <fcntl.h>
  58 #include <kvm.h>
  59 #include <limits.h>
  60 #include <signal.h>
  61 #include <stdio.h>
  62 #include <stdlib.h>
  63 #include <string.h>
  64 #include <unistd.h>
  65
  66 #include "extern.h"
  67
  68 static void     killed(int);
  69 static void     restart_target(void);
  70 static void     usage(void) __dead2;
  71
  72 kvm_t *kd;
  73
  74 static pid_t pid;
  75
  76 int
  77 main(int argc, char **argv)
  78 {
  79         struct exec exec;
  80         int ch, cnt, efd, fd, sflag;
  81         char *binfile, *corefile;
  82         char fname[MAXPATHLEN + 1];
  83
  84         sflag = 0;
  85         corefile = NULL;
  86         while ((ch = getopt(argc, argv, "c:s")) != -1) {
  87                 switch (ch) {
  88                 case 'c':
  89                         corefile = optarg;
  90                         break;
  91                 case 's':
  92                         sflag = 1;
  93                         break;
  94                 default:
  95                         usage();
  96                         break;
  97                 }
  98         }
  99         argv += optind;
 100         argc -= optind;
 101
 102         /* XXX we should check that the pid argument is really a number */
 103         switch (argc) {
 104         case 1:
 105                 pid = atoi(argv[0]);
 106                 asprintf(&binfile, "/proc/%d/file", pid);
 107                 if (binfile == NULL)
 108                         errx(1, "allocation failure");
 109                 break;
 110         case 2:
 111                 pid = atoi(argv[1]);
 112                 binfile = argv[0];
 113                 break;
 114         default:
 115                 usage();
 116         }
 117
 118         efd = open(binfile, O_RDONLY, 0);
 119         if (efd < 0)
 120                 err(1, "%s", binfile);
 121
 122         cnt = read(efd, &exec, sizeof(exec));
 123         if (cnt != sizeof(exec))
 124                 errx(1, "%s exec header: %s",
 125                     binfile, cnt > 0 ? strerror(EIO) : strerror(errno));
 126         if (IS_ELF(*(Elf_Ehdr *)&exec)) {
 127                 close(efd);
 128         } else
 129                 errx(1, "Invalid executable file");
 130
 131         if (corefile == NULL) {
 132                 (void)snprintf(fname, sizeof(fname), "core.%d", pid);
 133                 corefile = fname;
 134         }
 135         fd = open(corefile, O_RDWR|O_CREAT|O_TRUNC, DEFFILEMODE);
 136         if (fd < 0)
 137                 err(1, "%s", corefile);
 138
 139         if (sflag) {
 140                 signal(SIGHUP, killed);
 141                 signal(SIGINT, killed);
 142                 signal(SIGTERM, killed);
 143                 if (kill(pid, SIGSTOP) == -1)
 144                         err(1, "%d: stop signal", pid);
 145                 atexit(restart_target);
 146         }
 147
 148         elf_coredump(fd, pid);
 149
 150         (void)close(fd);
 151         exit(0);
 152 }
 153
 154 static void
 155 killed(int sig)
 156 {
 157         restart_target();
 158         signal(sig, SIG_DFL);
 159         kill(getpid(), sig);
 160 }
 161
 162 static void
 163 restart_target(void)
 164 {
 165         kill(pid, SIGCONT);
 166 }
 167
 168 void
 169 usage(void)
 170 {
 171         (void)fprintf(stderr, "usage: gcore [-s] [-c core] [executable] pid\n");
 172         exit(1);
 173 }