gcore.c revision 99112 
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#ifndef lint
41#if 0
42static char sccsid[] = "@(#)gcore.c	8.2 (Berkeley) 9/23/93";
43#endif
44#include <sys/cdefs.h>
45__FBSDID("$FreeBSD: head/usr.bin/gcore/gcore.c 99112 2002-06-30 05:25:07Z obrien $");
46
47/*
48 * Originally written by Eric Cooper in Fall 1981.
49 * Inspired by a version 6 program by Len Levin, 1978.
50 * Several pieces of code lifted from Bill Joy's 4BSD ps.
51 * Most recently, hacked beyond recognition for 4.4BSD by Steven McCanne,
52 * Lawrence Berkeley Laboratory.
53 *
54 * Portions of this software were developed by the Computer Systems
55 * Engineering group at Lawrence Berkeley Laboratory under DARPA
56 * contract BG 91-66 and contributed to Berkeley.
57 */
58
59#include <sys/param.h>
60#include <sys/time.h>
61#include <sys/stat.h>
62#include <sys/proc.h>
63#include <sys/user.h>
64#include <sys/sysctl.h>
65
66#include <machine/elf.h>
67#include <machine/vmparam.h>
68
69#include <a.out.h>
70#include <err.h>
71#include <fcntl.h>
72#include <kvm.h>
73#include <limits.h>
74#include <signal.h>
75#include <stdio.h>
76#include <stdlib.h>
77#include <string.h>
78#include <unistd.h>
79
80#include "extern.h"
81
82static void	core(int, int, struct kinfo_proc *);
83static void	datadump(int, int, struct kinfo_proc *, u_long, int);
84static void	killed(int);
85static void	restart_target(void);
86static void	usage(void) __dead2;
87static void	userdump(int, struct kinfo_proc *, u_long, int);
88
89kvm_t *kd;
90
91static int data_offset;
92static pid_t pid;
93
94int
95main(argc, argv)
96	int argc;
97	char *argv[];
98{
99	struct kinfo_proc *ki = NULL;
100	struct exec exec;
101	int ch, cnt, efd, fd, sflag, uid;
102	char *binfile, *corefile;
103	char errbuf[_POSIX2_LINE_MAX], fname[MAXPATHLEN];
104	int is_aout;
105
106	sflag = 0;
107	corefile = NULL;
108        while ((ch = getopt(argc, argv, "c:s")) != -1) {
109                switch (ch) {
110                case 'c':
111			corefile = optarg;
112                        break;
113		case 's':
114			sflag = 1;
115			break;
116		default:
117			usage();
118			break;
119		}
120	}
121	argv += optind;
122	argc -= optind;
123
124	/* XXX we should check that the pid argument is really a number */
125	switch (argc) {
126	case 1:
127		pid = atoi(argv[0]);
128		asprintf(&binfile, "/proc/%d/file", pid);
129		if (binfile == NULL)
130			errx(1, "allocation failure");
131		break;
132	case 2:
133		pid = atoi(argv[1]);
134		binfile = argv[0];
135		break;
136	default:
137		usage();
138	}
139
140	efd = open(binfile, O_RDONLY, 0);
141	if (efd < 0)
142		err(1, "%s", binfile);
143
144	cnt = read(efd, &exec, sizeof(exec));
145	if (cnt != sizeof(exec))
146		errx(1, "%s exec header: %s",
147		    binfile, cnt > 0 ? strerror(EIO) : strerror(errno));
148	if (!N_BADMAG(exec)) {
149		is_aout = 1;
150		/*
151		 * This legacy a.out support uses the kvm interface instead
152		 * of procfs.
153		 */
154		kd = kvm_openfiles(0, 0, 0, O_RDONLY, errbuf);
155		if (kd == NULL)
156			errx(1, "%s", errbuf);
157
158		uid = getuid();
159
160		ki = kvm_getprocs(kd, KERN_PROC_PID, pid, &cnt);
161		if (ki == NULL || cnt != 1)
162			errx(1, "%d: not found", pid);
163
164		if (ki->ki_ruid != uid && uid != 0)
165			errx(1, "%d: not owner", pid);
166
167		if (ki->ki_stat == SZOMB)
168			errx(1, "%d: zombie", pid);
169
170		if (ki->ki_flag & P_WEXIT)
171			errx(1, "%d: process exiting", pid);
172		if (ki->ki_flag & P_SYSTEM)	/* Swapper or pagedaemon. */
173			errx(1, "%d: system process", pid);
174		if (exec.a_text != ptoa(ki->ki_tsize))
175			errx(1, "The executable %s does not belong to"
176			    " process %d!\n"
177			    "Text segment size (in bytes): executable %ld,"
178			    " process %d", binfile, pid, exec.a_text,
179			     ptoa(ki->ki_tsize));
180		data_offset = N_DATOFF(exec);
181	} else if (IS_ELF(*(Elf_Ehdr *)&exec)) {
182		is_aout = 0;
183		close(efd);
184	} else
185		errx(1, "Invalid executable file");
186
187	if (corefile == NULL) {
188		(void)snprintf(fname, sizeof(fname), "core.%d", pid);
189		corefile = fname;
190	}
191	fd = open(corefile, O_RDWR|O_CREAT|O_TRUNC, DEFFILEMODE);
192	if (fd < 0)
193		err(1, "%s", corefile);
194
195	if (sflag) {
196		signal(SIGHUP, killed);
197		signal(SIGINT, killed);
198		signal(SIGTERM, killed);
199		if (kill(pid, SIGSTOP) == -1)
200			err(1, "%d: stop signal", pid);
201		atexit(restart_target);
202	}
203
204	if (is_aout)
205		core(efd, fd, ki);
206	else
207		elf_coredump(fd, pid);
208
209	(void)close(fd);
210	exit(0);
211}
212
213/*
214 * core --
215 *	Build the core file.
216 */
217void
218core(efd, fd, ki)
219	int efd;
220	int fd;
221	struct kinfo_proc *ki;
222{
223	union {
224		struct user user;
225		struct {
226			char uabytes[ctob(UAREA_PAGES)];
227			char ksbytes[ctob(KSTACK_PAGES)];
228		} bytes;
229	} uarea;
230	int tsize = ki->ki_tsize;
231	int dsize = ki->ki_dsize;
232	int ssize = ki->ki_ssize;
233	int cnt;
234
235	/* Read in user struct */
236	cnt = kvm_read(kd, (u_long)ki->ki_addr, uarea.bytes.uabytes,
237	    ctob(UAREA_PAGES));
238	if (cnt != ctob(UAREA_PAGES))
239		errx(1, "read upages structure: %s",
240		    cnt > 0 ? strerror(EIO) : strerror(errno));
241
242	cnt = kvm_read(kd, (u_long)ki->ki_kstack, uarea.bytes.ksbytes,
243	    ctob(KSTACK_PAGES));
244	if (cnt != ctob(KSTACK_PAGES))
245		errx(1, "read kstack structure: %s",
246		    cnt > 0 ? strerror(EIO) : strerror(errno));
247
248	/*
249	 * Fill in the eproc vm parameters, since these are garbage unless
250	 * the kernel is dumping core or something.
251	 */
252	uarea.user.u_kproc = *ki;
253
254	/* Dump user area */
255	cnt = write(fd, &uarea, sizeof(uarea));
256	if (cnt != sizeof(uarea))
257		errx(1, "write user structure: %s",
258		    cnt > 0 ? strerror(EIO) : strerror(errno));
259
260	/* Dump data segment */
261	datadump(efd, fd, ki, USRTEXT + ctob(tsize), dsize);
262
263	/* Dump stack segment */
264	userdump(fd, ki, USRSTACK - ctob(ssize), ssize);
265
266	/* Dump machine dependent portions of the core. */
267	md_core(kd, fd, ki);
268}
269
270void
271datadump(efd, fd, kp, addr, npage)
272	register int efd;
273	register int fd;
274	struct kinfo_proc *kp;
275	register u_long addr;
276	register int npage;
277{
278	register int cc, delta;
279	char buffer[PAGE_SIZE];
280
281	delta = data_offset - addr;
282	while (--npage >= 0) {
283		cc = kvm_uread(kd, kp, addr, buffer, PAGE_SIZE);
284		if (cc != PAGE_SIZE) {
285			/* Try to read the page from the executable. */
286			if (lseek(efd, (off_t)addr + delta, SEEK_SET) == -1)
287				err(1, "seek executable");
288			cc = read(efd, buffer, sizeof(buffer));
289			if (cc != sizeof(buffer)) {
290				if (cc < 0)
291					err(1, "read executable");
292				else	/* Assume untouched bss page. */
293					bzero(buffer, sizeof(buffer));
294			}
295		}
296		cc = write(fd, buffer, PAGE_SIZE);
297		if (cc != PAGE_SIZE)
298			errx(1, "write data segment: %s",
299			    cc > 0 ? strerror(EIO) : strerror(errno));
300		addr += PAGE_SIZE;
301	}
302}
303
304static void
305killed(sig)
306	int sig;
307{
308	restart_target();
309	signal(sig, SIG_DFL);
310	kill(getpid(), sig);
311}
312
313static void
314restart_target()
315{
316	kill(pid, SIGCONT);
317}
318
319void
320userdump(fd, kp, addr, npage)
321	register int fd;
322	struct kinfo_proc *kp;
323	register u_long addr;
324	register int npage;
325{
326	register int cc;
327	char buffer[PAGE_SIZE];
328
329	while (--npage >= 0) {
330		cc = kvm_uread(kd, kp, addr, buffer, PAGE_SIZE);
331		if (cc != PAGE_SIZE)
332			/* Could be an untouched fill-with-zero page. */
333			bzero(buffer, PAGE_SIZE);
334		cc = write(fd, buffer, PAGE_SIZE);
335		if (cc != PAGE_SIZE)
336			errx(1, "write stack segment: %s",
337			    cc > 0 ? strerror(EIO) : strerror(errno));
338		addr += PAGE_SIZE;
339	}
340}
341
342void
343usage()
344{
345	(void)fprintf(stderr, "usage: gcore [-s] [-c core] [executable] pid\n");
346	exit(1);
347}
348