rtld_db.c revision 330897 
1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2010 The FreeBSD Foundation
5 * All rights reserved.
6 *
7 * This software was developed by Rui Paulo under sponsorship from the
8 * FreeBSD Foundation.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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#include <sys/cdefs.h>
32__FBSDID("$FreeBSD: stable/11/lib/librtld_db/rtld_db.c 330897 2018-03-14 03:19:51Z eadler $");
33
34#include <sys/param.h>
35#include <sys/sysctl.h>
36#include <sys/user.h>
37
38#include <err.h>
39#include <stdio.h>
40#include <stdlib.h>
41#include <string.h>
42#include <limits.h>
43#include <libproc.h>
44#include <libutil.h>
45
46#include "rtld_db.h"
47
48static int _librtld_db_debug = 0;
49#define DPRINTF(...) do {				\
50	if (_librtld_db_debug) {			\
51		fprintf(stderr, "librtld_db: DEBUG: ");	\
52		fprintf(stderr, __VA_ARGS__);		\
53	}						\
54} while (0)
55
56void
57rd_delete(rd_agent_t *rdap)
58{
59
60	free(rdap);
61}
62
63const char *
64rd_errstr(rd_err_e rderr)
65{
66
67	switch (rderr) {
68	case RD_ERR:
69		return "generic error";
70	case RD_OK:
71		return "no error";
72	case RD_NOCAPAB:
73		return "capability not supported";
74	case RD_DBERR:
75		return "database error";
76	case RD_NOBASE:
77		return "NOBASE";
78	case RD_NOMAPS:
79		return "NOMAPS";
80	default:
81		return "unknown error";
82	}
83}
84
85rd_err_e
86rd_event_addr(rd_agent_t *rdap, rd_event_e event, rd_notify_t *notify)
87{
88	rd_err_e ret;
89
90	DPRINTF("%s rdap %p event %d notify %p\n", __func__, rdap, event,
91	    notify);
92
93	ret = RD_OK;
94	switch (event) {
95	case RD_NONE:
96		break;
97	case RD_PREINIT:
98		notify->type = RD_NOTIFY_BPT;
99		notify->u.bptaddr = rdap->rda_preinit_addr;
100		break;
101	case RD_POSTINIT:
102		notify->type = RD_NOTIFY_BPT;
103		notify->u.bptaddr = rdap->rda_postinit_addr;
104		break;
105	case RD_DLACTIVITY:
106		notify->type = RD_NOTIFY_BPT;
107		notify->u.bptaddr = rdap->rda_dlactivity_addr;
108		break;
109	default:
110		ret = RD_ERR;
111		break;
112	}
113	return (ret);
114}
115
116rd_err_e
117rd_event_enable(rd_agent_t *rdap __unused, int onoff)
118{
119	DPRINTF("%s onoff %d\n", __func__, onoff);
120
121	return (RD_OK);
122}
123
124rd_err_e
125rd_event_getmsg(rd_agent_t *rdap __unused, rd_event_msg_t *msg)
126{
127	DPRINTF("%s\n", __func__);
128
129	msg->type = RD_POSTINIT;
130	msg->u.state = RD_CONSISTENT;
131
132	return (RD_OK);
133}
134
135rd_err_e
136rd_init(int version)
137{
138	char *debug = NULL;
139
140	if (version == RD_VERSION) {
141		debug = getenv("LIBRTLD_DB_DEBUG");
142		_librtld_db_debug = debug ? atoi(debug) : 0;
143		return (RD_OK);
144	} else
145		return (RD_NOCAPAB);
146}
147
148rd_err_e
149rd_loadobj_iter(rd_agent_t *rdap, rl_iter_f *cb, void *clnt_data)
150{
151	int cnt, i, lastvn = 0;
152	rd_loadobj_t rdl;
153	struct kinfo_vmentry *kves, *kve;
154
155	DPRINTF("%s\n", __func__);
156
157	if ((kves = kinfo_getvmmap(proc_getpid(rdap->rda_php), &cnt)) == NULL) {
158		warn("ERROR: kinfo_getvmmap() failed");
159		return (RD_ERR);
160	}
161	for (i = 0; i < cnt; i++) {
162		kve = kves + i;
163		if (kve->kve_type == KVME_TYPE_VNODE)
164			lastvn = i;
165		memset(&rdl, 0, sizeof(rdl));
166		/*
167		 * Map the kinfo_vmentry struct to the rd_loadobj structure.
168		 */
169		rdl.rdl_saddr = kve->kve_start;
170		rdl.rdl_eaddr = kve->kve_end;
171		rdl.rdl_offset = kve->kve_offset;
172		if (kve->kve_protection & KVME_PROT_READ)
173			rdl.rdl_prot |= RD_RDL_R;
174		if (kve->kve_protection & KVME_PROT_WRITE)
175			rdl.rdl_prot |= RD_RDL_W;
176		if (kve->kve_protection & KVME_PROT_EXEC)
177			rdl.rdl_prot |= RD_RDL_X;
178		strlcpy(rdl.rdl_path, kves[lastvn].kve_path,
179			sizeof(rdl.rdl_path));
180		(*cb)(&rdl, clnt_data);
181	}
182	free(kves);
183
184	return (RD_OK);
185}
186
187void
188rd_log(const int onoff)
189{
190	DPRINTF("%s\n", __func__);
191
192	(void)onoff;
193}
194
195rd_agent_t *
196rd_new(struct proc_handle *php)
197{
198	rd_agent_t *rdap;
199
200	rdap = malloc(sizeof(rd_agent_t));
201	if (rdap) {
202		memset(rdap, 0, sizeof(rd_agent_t));
203		rdap->rda_php = php;
204		rd_reset(rdap);
205	}
206
207	return (rdap);
208}
209
210rd_err_e
211rd_objpad_enable(rd_agent_t *rdap, size_t padsize)
212{
213	DPRINTF("%s\n", __func__);
214
215	(void)rdap;
216	(void)padsize;
217
218	return (RD_ERR);
219}
220
221rd_err_e
222rd_plt_resolution(rd_agent_t *rdap, uintptr_t pc, struct proc *proc,
223    uintptr_t plt_base, rd_plt_info_t *rpi)
224{
225	DPRINTF("%s\n", __func__);
226
227	(void)rdap;
228	(void)pc;
229	(void)proc;
230	(void)plt_base;
231	(void)rpi;
232
233	return (RD_ERR);
234}
235
236rd_err_e
237rd_reset(rd_agent_t *rdap)
238{
239	GElf_Sym sym;
240
241	if (proc_name2sym(rdap->rda_php, "ld-elf.so.1", "r_debug_state",
242	    &sym, NULL) < 0)
243		return (RD_ERR);
244	DPRINTF("found r_debug_state at 0x%lx\n", (unsigned long)sym.st_value);
245	rdap->rda_preinit_addr = sym.st_value;
246	rdap->rda_dlactivity_addr = sym.st_value;
247
248	if (proc_name2sym(rdap->rda_php, "ld-elf.so.1", "_r_debug_postinit",
249	    &sym, NULL) < 0)
250		return (RD_ERR);
251	DPRINTF("found _r_debug_postinit at 0x%lx\n",
252	    (unsigned long)sym.st_value);
253	rdap->rda_postinit_addr = sym.st_value;
254
255	return (RD_OK);
256}
257