gcore.c revision 50477 
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
44static const char rcsid[] =
45  "$FreeBSD: head/usr.bin/gcore/gcore.c 50477 1999-08-28 01:08:13Z peter $";
46#endif /* not lint */
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#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/vmparam.h>
67
68#include <a.out.h>
69#include <elf.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 __P((int, int, struct kinfo_proc *));
83static void	datadump __P((int, int, struct proc *, u_long, int));
84static void	killed __P((int));
85static void	restart_target __P((void));
86static void	usage __P((void)) __dead2;
87static void	userdump __P((int, struct proc *, u_long, int));
88
89kvm_t *kd;
90/* XXX undocumented routine, should be in kvm.h? */
91ssize_t kvm_uread __P((kvm_t *, const struct proc *, u_long, char *, size_t));
92
93static int data_offset;
94static pid_t pid;
95
96int
97main(argc, argv)
98	int argc;
99	char *argv[];
100{
101	register struct proc *p;
102	struct kinfo_proc *ki = NULL;
103	struct exec exec;
104	int ch, cnt, efd, fd, sflag, uid;
105	char *binfile, *corefile;
106	char errbuf[_POSIX2_LINE_MAX], fname[MAXPATHLEN + 1];
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		p = &ki->kp_proc;
168		if (ki->kp_eproc.e_pcred.p_ruid != uid && uid != 0)
169			errx(1, "%d: not owner", pid);
170
171		if (p->p_stat == SZOMB)
172			errx(1, "%d: zombie", pid);
173
174		if (p->p_flag & P_WEXIT)
175			errx(1, "%d: process exiting", pid);
176		if (p->p_flag & P_SYSTEM)	/* Swapper or pagedaemon. */
177			errx(1, "%d: system process", pid);
178		if (exec.a_text != ptoa(ki->kp_eproc.e_vm.vm_tsize))
179			errx(1, "The executable %s does not belong to"
180			    " process %d!\n"
181			    "Text segment size (in bytes): executable %ld,"
182			    " process %d", binfile, pid, exec.a_text,
183			     ptoa(ki->kp_eproc.e_vm.vm_tsize));
184		data_offset = N_DATOFF(exec);
185	} else if (IS_ELF(*(Elf_Ehdr *)&exec)) {
186		is_aout = 0;
187		close(efd);
188	} else
189		errx(1, "Invalid executable file");
190
191	if (corefile == NULL) {
192		(void)snprintf(fname, sizeof(fname), "core.%d", pid);
193		corefile = fname;
194	}
195	fd = open(corefile, O_RDWR|O_CREAT|O_TRUNC, DEFFILEMODE);
196	if (fd < 0)
197		err(1, "%s", corefile);
198
199	if (sflag) {
200		signal(SIGHUP, killed);
201		signal(SIGINT, killed);
202		signal(SIGTERM, killed);
203		if (kill(pid, SIGSTOP) == -1)
204			err(1, "%d: stop signal", pid);
205		atexit(restart_target);
206	}
207
208	if (is_aout)
209		core(efd, fd, ki);
210	else
211		elf_coredump(fd, pid);
212
213	(void)close(fd);
214	exit(0);
215}
216
217/*
218 * core --
219 *	Build the core file.
220 */
221void
222core(efd, fd, ki)
223	int efd;
224	int fd;
225	struct kinfo_proc *ki;
226{
227	union {
228		struct user user;
229		char ubytes[ctob(UPAGES)];
230	} uarea;
231	struct proc *p = &ki->kp_proc;
232	int tsize = ki->kp_eproc.e_vm.vm_tsize;
233	int dsize = ki->kp_eproc.e_vm.vm_dsize;
234	int ssize = ki->kp_eproc.e_vm.vm_ssize;
235	int cnt;
236
237	/* Read in user struct */
238	cnt = kvm_read(kd, (u_long)p->p_addr, &uarea, sizeof(uarea));
239	if (cnt != sizeof(uarea))
240		errx(1, "read user structure: %s",
241		    cnt > 0 ? strerror(EIO) : strerror(errno));
242
243	/*
244	 * Fill in the eproc vm parameters, since these are garbage unless
245	 * the kernel is dumping core or something.
246	 */
247	uarea.user.u_kproc = *ki;
248
249	/* Dump user area */
250	cnt = write(fd, &uarea, sizeof(uarea));
251	if (cnt != sizeof(uarea))
252		errx(1, "write user structure: %s",
253		    cnt > 0 ? strerror(EIO) : strerror(errno));
254
255	/* Dump data segment */
256	datadump(efd, fd, p, USRTEXT + ctob(tsize), dsize);
257
258	/* Dump stack segment */
259	userdump(fd, p, USRSTACK - ctob(ssize), ssize);
260
261	/* Dump machine dependent portions of the core. */
262	md_core(kd, fd, ki);
263}
264
265void
266datadump(efd, fd, p, addr, npage)
267	register int efd;
268	register int fd;
269	struct proc *p;
270	register u_long addr;
271	register int npage;
272{
273	register int cc, delta;
274	char buffer[PAGE_SIZE];
275
276	delta = data_offset - addr;
277	while (--npage >= 0) {
278		cc = kvm_uread(kd, p, addr, buffer, PAGE_SIZE);
279		if (cc != PAGE_SIZE) {
280			/* Try to read the page from the executable. */
281			if (lseek(efd, (off_t)addr + delta, SEEK_SET) == -1)
282				err(1, "seek executable: %s", strerror(errno));
283			cc = read(efd, buffer, sizeof(buffer));
284			if (cc != sizeof(buffer)) {
285				if (cc < 0)
286					err(1, "read executable");
287				else	/* Assume untouched bss page. */
288					bzero(buffer, sizeof(buffer));
289			}
290		}
291		cc = write(fd, buffer, PAGE_SIZE);
292		if (cc != PAGE_SIZE)
293			errx(1, "write data segment: %s",
294			    cc > 0 ? strerror(EIO) : strerror(errno));
295		addr += PAGE_SIZE;
296	}
297}
298
299static void
300killed(sig)
301	int sig;
302{
303	restart_target();
304	signal(sig, SIG_DFL);
305	kill(getpid(), sig);
306}
307
308static void
309restart_target()
310{
311	kill(pid, SIGCONT);
312}
313
314void
315userdump(fd, p, addr, npage)
316	register int fd;
317	struct proc *p;
318	register u_long addr;
319	register int npage;
320{
321	register int cc;
322	char buffer[PAGE_SIZE];
323
324	while (--npage >= 0) {
325		cc = kvm_uread(kd, p, addr, buffer, PAGE_SIZE);
326		if (cc != PAGE_SIZE)
327			/* Could be an untouched fill-with-zero page. */
328			bzero(buffer, PAGE_SIZE);
329		cc = write(fd, buffer, PAGE_SIZE);
330		if (cc != PAGE_SIZE)
331			errx(1, "write stack segment: %s",
332			    cc > 0 ? strerror(EIO) : strerror(errno));
333		addr += PAGE_SIZE;
334	}
335}
336
337void
338usage()
339{
340	(void)fprintf(stderr, "usage: gcore [-s] [-c core] executable pid\n");
341	exit(1);
342}
343