xref: /freebsd/usr.bin/gcore/gcore.c (revision 06c3fb2749bda94cb5201f81ffdb8fa6c3161b2e)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1992, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 /*
33  * Originally written by Eric Cooper in Fall 1981.
34  * Inspired by a version 6 program by Len Levin, 1978.
35  * Several pieces of code lifted from Bill Joy's 4BSD ps.
36  * Most recently, hacked beyond recognition for 4.4BSD by Steven McCanne,
37  * Lawrence Berkeley Laboratory.
38  *
39  * Portions of this software were developed by the Computer Systems
40  * Engineering group at Lawrence Berkeley Laboratory under DARPA
41  * contract BG 91-66 and contributed to Berkeley.
42  */
43 
44 #include <sys/param.h>
45 #include <sys/ptrace.h>
46 #include <sys/time.h>
47 #include <sys/stat.h>
48 #include <sys/linker_set.h>
49 #include <sys/sysctl.h>
50 #include <sys/wait.h>
51 
52 #include <err.h>
53 #include <fcntl.h>
54 #include <stdbool.h>
55 #include <stdio.h>
56 #include <stdlib.h>
57 #include <string.h>
58 #include <unistd.h>
59 
60 #include "extern.h"
61 int pflags;
62 
63 static void	killed(int);
64 static void	usage(void) __dead2;
65 
66 static pid_t pid;
67 static bool kflag = false;
68 
69 SET_DECLARE(dumpset, struct dumpers);
70 
71 static int
72 open_corefile(char *corefile)
73 {
74 	char fname[MAXPATHLEN];
75 	int fd;
76 
77 	if (corefile == NULL) {
78 		(void)snprintf(fname, sizeof(fname), "core.%d", pid);
79 		corefile = fname;
80 	}
81 	fd = open(corefile, O_RDWR | O_CREAT | O_TRUNC, DEFFILEMODE);
82 	if (fd < 0)
83 		err(1, "%s", corefile);
84 	return (fd);
85 }
86 
87 static void
88 kcoredump(int fd, pid_t pid)
89 {
90 	struct ptrace_coredump pc;
91 	int error, res, ret, waited;
92 
93 	error = ptrace(PT_ATTACH, pid, NULL, 0);
94 	if (error != 0)
95 		err(1, "attach");
96 
97 	waited = waitpid(pid, &res, 0);
98 	if (waited == -1)
99 		err(1, "wait for STOP");
100 
101 	ret = 0;
102 	memset(&pc, 0, sizeof(pc));
103 	pc.pc_fd = fd;
104 	pc.pc_flags = (pflags & PFLAGS_FULL) != 0 ? PC_ALL : 0;
105 	error = ptrace(PT_COREDUMP, pid, (void *)&pc, sizeof(pc));
106 	if (error == -1) {
107 		warn("coredump");
108 		ret = 1;
109 	}
110 
111 	waited = waitpid(pid, &res, WNOHANG);
112 	if (waited == -1) {
113 		warn("wait after coredump");
114 		ret = 1;
115 	}
116 
117 	error = ptrace(PT_DETACH, pid, NULL, 0);
118 	if (error == -1) {
119 		warn("detach failed, check process status");
120 		ret = 1;
121 	}
122 
123 	exit(ret);
124 }
125 
126 int
127 main(int argc, char *argv[])
128 {
129 	int ch, efd, fd, name[4];
130 	char *binfile, *corefile;
131 	char passpath[MAXPATHLEN];
132 	struct dumpers **d, *dumper;
133 	size_t len;
134 
135 	pflags = 0;
136 	corefile = NULL;
137         while ((ch = getopt(argc, argv, "c:fk")) != -1) {
138                 switch (ch) {
139                 case 'c':
140 			corefile = optarg;
141                         break;
142 		case 'f':
143 			pflags |= PFLAGS_FULL;
144 			break;
145 		case 'k':
146 			kflag = true;
147 			break;
148 		default:
149 			usage();
150 			break;
151 		}
152 	}
153 	argv += optind;
154 	argc -= optind;
155 
156 	/* XXX we should check that the pid argument is really a number */
157 	switch (argc) {
158 	case 1:
159 		pid = atoi(argv[0]);
160 		break;
161 	case 2:
162 		binfile = argv[0];
163 		pid = atoi(argv[1]);
164 		break;
165 	default:
166 		usage();
167 	}
168 
169 	if (kflag) {
170 		fd = open_corefile(corefile);
171 		kcoredump(fd, pid);
172 	}
173 
174 	if (argc == 1) {
175 		name[0] = CTL_KERN;
176 		name[1] = KERN_PROC;
177 		name[2] = KERN_PROC_PATHNAME;
178 		name[3] = pid;
179 		len = sizeof(passpath);
180 		if (sysctl(name, 4, passpath, &len, NULL, 0) == -1)
181 			errx(1, "kern.proc.pathname failure");
182 		binfile = passpath;
183 	}
184 	efd = open(binfile, O_RDONLY, 0);
185 	if (efd < 0)
186 		err(1, "%s", binfile);
187 	dumper = NULL;
188 	SET_FOREACH(d, dumpset) {
189 		lseek(efd, 0, SEEK_SET);
190 		if (((*d)->ident)(efd, pid, binfile)) {
191 			dumper = (*d);
192 			lseek(efd, 0, SEEK_SET);
193 			break;
194 		}
195 	}
196 	if (dumper == NULL)
197 		errx(1, "Invalid executable file");
198 	fd = open_corefile(corefile);
199 
200 	dumper->dump(efd, fd, pid);
201 	(void)close(fd);
202 	(void)close(efd);
203 	exit(0);
204 }
205 
206 void
207 usage(void)
208 {
209 
210 	(void)fprintf(stderr,
211 	    "usage: gcore [-kf] [-c core] [executable] pid\n");
212 	exit(1);
213 }
214