gcore.c revision 102955 
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. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#ifndef lint
35static const char copyright[] =
36"@(#) Copyright (c) 1992, 1993\n\
37	The Regents of the University of California.  All rights reserved.\n";
38#endif /* not lint */
39
40#if 0
41#ifndef lint
42static char sccsid[] = "@(#)gcore.c	8.2 (Berkeley) 9/23/93";
43#endif /* not lint */
44#endif
45#include <sys/cdefs.h>
46__FBSDID("$FreeBSD: head/usr.bin/gcore/gcore.c 102944 2002-09-04 23:29:10Z dwmalone $");
47
48/*
49 * Originally written by Eric Cooper in Fall 1981.
50 * Inspired by a version 6 program by Len Levin, 1978.
51 * Several pieces of code lifted from Bill Joy's 4BSD ps.
52 * Most recently, hacked beyond recognition for 4.4BSD by Steven McCanne,
53 * Lawrence Berkeley Laboratory.
54 *
55 * Portions of this software were developed by the Computer Systems
56 * Engineering group at Lawrence Berkeley Laboratory under DARPA
57 * contract BG 91-66 and contributed to Berkeley.
58 */
59
60#include <sys/param.h>
61#include <sys/time.h>
62#include <sys/stat.h>
63#include <sys/proc.h>
64#include <sys/user.h>
65#include <sys/sysctl.h>
66
67#include <arpa/inet.h>
68#include <machine/elf.h>
69#include <machine/vmparam.h>
70
71#include <a.out.h>
72#include <err.h>
73#include <fcntl.h>
74#include <kvm.h>
75#include <limits.h>
76#include <signal.h>
77#include <stdio.h>
78#include <stdlib.h>
79#include <string.h>
80#include <unistd.h>
81
82#include "extern.h"
83
84static void	core(int, int, struct kinfo_proc *);
85static void	datadump(int, int, struct kinfo_proc *, u_long, int);
86static void	killed(int);
87static void	restart_target(void);
88static void	usage(void) __dead2;
89static void	userdump(int, struct kinfo_proc *, u_long, int);
90
91kvm_t *kd;
92
93static int data_offset;
94static pid_t pid;
95
96int
97main(argc, argv)
98	int argc;
99	char *argv[];
100{
101	struct kinfo_proc *ki = NULL;
102	struct exec exec;
103	int ch, cnt, efd, fd, sflag;
104	uid_t uid;
105	char *binfile, *corefile;
106	char errbuf[_POSIX2_LINE_MAX], fname[MAXPATHLEN];
107	int is_aout;
108
109	sflag = 0;
110	corefile = NULL;
111        while ((ch = getopt(argc, argv, "c:s")) != -1) {
112                switch (ch) {
113                case 'c':
114			corefile = optarg;
115                        break;
116		case 's':
117			sflag = 1;
118			break;
119		default:
120			usage();
121			break;
122		}
123	}
124	argv += optind;
125	argc -= optind;
126
127	/* XXX we should check that the pid argument is really a number */
128	switch (argc) {
129	case 1:
130		pid = atoi(argv[0]);
131		asprintf(&binfile, "/proc/%d/file", pid);
132		if (binfile == NULL)
133			errx(1, "allocation failure");
134		break;
135	case 2:
136		pid = atoi(argv[1]);
137		binfile = argv[0];
138		break;
139	default:
140		usage();
141	}
142
143	efd = open(binfile, O_RDONLY, 0);
144	if (efd < 0)
145		err(1, "%s", binfile);
146
147	cnt = read(efd, &exec, sizeof(exec));
148	if (cnt != sizeof(exec))
149		errx(1, "%s exec header: %s",
150		    binfile, cnt > 0 ? strerror(EIO) : strerror(errno));
151	if (!N_BADMAG(exec)) {
152		is_aout = 1;
153		/*
154		 * This legacy a.out support uses the kvm interface instead
155		 * of procfs.
156		 */
157		kd = kvm_openfiles(0, 0, 0, O_RDONLY, errbuf);
158		if (kd == NULL)
159			errx(1, "%s", errbuf);
160
161		uid = getuid();
162
163		ki = kvm_getprocs(kd, KERN_PROC_PID, pid, &cnt);
164		if (ki == NULL || cnt != 1)
165			errx(1, "%d: not found", pid);
166
167		if (ki->ki_ruid != uid && uid != 0)
168			errx(1, "%d: not owner", pid);
169
170		if (ki->ki_stat == SZOMB)
171			errx(1, "%d: zombie", pid);
172
173		if (ki->ki_flag & P_WEXIT)
174			errx(1, "%d: process exiting", pid);
175		if (ki->ki_flag & P_SYSTEM)	/* Swapper or pagedaemon. */
176			errx(1, "%d: system process", pid);
177		if (exec.a_text != ptoa(ki->ki_tsize))
178			errx(1, "The executable %s does not belong to"
179			    " process %d!\n"
180			    "Text segment size (in bytes): executable %ld,"
181			    " process %d", binfile, pid, exec.a_text,
182			     ptoa(ki->ki_tsize));
183		data_offset = N_DATOFF(exec);
184	} else if (IS_ELF(*(Elf_Ehdr *)&exec)) {
185		is_aout = 0;
186		close(efd);
187	} else
188		errx(1, "Invalid executable file");
189
190	if (corefile == NULL) {
191		(void)snprintf(fname, sizeof(fname), "core.%d", pid);
192		corefile = fname;
193	}
194	fd = open(corefile, O_RDWR|O_CREAT|O_TRUNC, DEFFILEMODE);
195	if (fd < 0)
196		err(1, "%s", corefile);
197
198	if (sflag) {
199		signal(SIGHUP, killed);
200		signal(SIGINT, killed);
201		signal(SIGTERM, killed);
202		if (kill(pid, SIGSTOP) == -1)
203			err(1, "%d: stop signal", pid);
204		atexit(restart_target);
205	}
206
207	if (is_aout)
208		core(efd, fd, ki);
209	else
210		elf_coredump(fd, pid);
211
212	(void)close(fd);
213	exit(0);
214}
215
216/*
217 * core --
218 *	Build the core file.
219 */
220void
221core(efd, fd, ki)
222	int efd;
223	int fd;
224	struct kinfo_proc *ki;
225{
226	union {
227		struct user user;
228		struct {
229			char uabytes[ctob(UAREA_PAGES)];
230			char ksbytes[ctob(KSTACK_PAGES)];
231		} bytes;
232	} uarea;
233	int tsize = ki->ki_tsize;
234	int dsize = ki->ki_dsize;
235	int ssize = ki->ki_ssize;
236	int cnt;
237
238	/* Read in user struct */
239	cnt = kvm_read(kd, (u_long)ki->ki_addr, uarea.bytes.uabytes,
240	    ctob(UAREA_PAGES));
241	if (cnt != ctob(UAREA_PAGES))
242		errx(1, "read upages structure: %s",
243		    cnt > 0 ? strerror(EIO) : strerror(errno));
244
245	cnt = kvm_read(kd, (u_long)ki->ki_kstack, uarea.bytes.ksbytes,
246	    ctob(KSTACK_PAGES));
247	if (cnt != ctob(KSTACK_PAGES))
248		errx(1, "read kstack structure: %s",
249		    cnt > 0 ? strerror(EIO) : strerror(errno));
250
251	/*
252	 * Fill in the eproc vm parameters, since these are garbage unless
253	 * the kernel is dumping core or something.
254	 */
255	uarea.user.u_kproc = *ki;
256
257	/* Dump user area */
258	cnt = write(fd, &uarea, sizeof(uarea));
259	if (cnt != sizeof(uarea))
260		errx(1, "write user structure: %s",
261		    cnt > 0 ? strerror(EIO) : strerror(errno));
262
263	/* Dump data segment */
264	datadump(efd, fd, ki, USRTEXT + ctob(tsize), dsize);
265
266	/* Dump stack segment */
267	userdump(fd, ki, USRSTACK - ctob(ssize), ssize);
268
269	/* Dump machine dependent portions of the core. */
270	md_core(kd, fd, ki);
271}
272
273void
274datadump(efd, fd, kp, addr, npage)
275	register int efd;
276	register int fd;
277	struct kinfo_proc *kp;
278	register u_long addr;
279	register int npage;
280{
281	register int cc, delta;
282	char buffer[PAGE_SIZE];
283
284	delta = data_offset - addr;
285	while (--npage >= 0) {
286		cc = kvm_uread(kd, kp, addr, buffer, PAGE_SIZE);
287		if (cc != PAGE_SIZE) {
288			/* Try to read the page from the executable. */
289			if (lseek(efd, (off_t)addr + delta, SEEK_SET) == -1)
290				err(1, "seek executable");
291			cc = read(efd, buffer, sizeof(buffer));
292			if (cc != sizeof(buffer)) {
293				if (cc < 0)
294					err(1, "read executable");
295				else	/* Assume untouched bss page. */
296					bzero(buffer, sizeof(buffer));
297			}
298		}
299		cc = write(fd, buffer, PAGE_SIZE);
300		if (cc != PAGE_SIZE)
301			errx(1, "write data segment: %s",
302			    cc > 0 ? strerror(EIO) : strerror(errno));
303		addr += PAGE_SIZE;
304	}
305}
306
307static void
308killed(sig)
309	int sig;
310{
311	restart_target();
312	signal(sig, SIG_DFL);
313	kill(getpid(), sig);
314}
315
316static void
317restart_target()
318{
319	kill(pid, SIGCONT);
320}
321
322void
323userdump(fd, kp, addr, npage)
324	register int fd;
325	struct kinfo_proc *kp;
326	register u_long addr;
327	register int npage;
328{
329	register int cc;
330	char buffer[PAGE_SIZE];
331
332	while (--npage >= 0) {
333		cc = kvm_uread(kd, kp, addr, buffer, PAGE_SIZE);
334		if (cc != PAGE_SIZE)
335			/* Could be an untouched fill-with-zero page. */
336			bzero(buffer, PAGE_SIZE);
337		cc = write(fd, buffer, PAGE_SIZE);
338		if (cc != PAGE_SIZE)
339			errx(1, "write stack segment: %s",
340			    cc > 0 ? strerror(EIO) : strerror(errno));
341		addr += PAGE_SIZE;
342	}
343}
344
345void
346usage()
347{
348	(void)fprintf(stderr, "usage: gcore [-s] [-c core] [executable] pid\n");
349	exit(1);
350}
351