1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
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
32#include <sys/param.h>
33#include <sys/sysctl.h>
34#include <sys/user.h>
35
36#include <assert.h>
37#include <err.h>
38#include <fcntl.h>
39#include <limits.h>
40#include <stdio.h>
41#include <stdlib.h>
42#include <string.h>
43#include <unistd.h>
44
45#include <machine/elf.h>
46
47#include <libelf.h>
48#include <libproc.h>
49#include <libprocstat.h>
50#include <libutil.h>
51
52#include "rtld_db.h"
53
54static int _librtld_db_debug = 0;
55#define DPRINTF(...) do {				\
56	if (_librtld_db_debug) {			\
57		fprintf(stderr, "librtld_db: DEBUG: ");	\
58		fprintf(stderr, __VA_ARGS__);		\
59	}						\
60} while (0)
61
62void
63rd_delete(rd_agent_t *rdap)
64{
65
66	if (rdap->rda_procstat != NULL)
67		procstat_close(rdap->rda_procstat);
68	free(rdap);
69}
70
71const char *
72rd_errstr(rd_err_e rderr)
73{
74
75	switch (rderr) {
76	case RD_ERR:
77		return "generic error";
78	case RD_OK:
79		return "no error";
80	case RD_NOCAPAB:
81		return "capability not supported";
82	case RD_DBERR:
83		return "database error";
84	case RD_NOBASE:
85		return "NOBASE";
86	case RD_NOMAPS:
87		return "NOMAPS";
88	default:
89		return "unknown error";
90	}
91}
92
93rd_err_e
94rd_event_addr(rd_agent_t *rdap, rd_event_e event, rd_notify_t *notify)
95{
96	rd_err_e ret;
97
98	DPRINTF("%s rdap %p event %d notify %p\n", __func__, rdap, event,
99	    notify);
100
101	ret = RD_OK;
102	switch (event) {
103	case RD_NONE:
104		break;
105	case RD_PREINIT:
106		notify->type = RD_NOTIFY_BPT;
107		notify->u.bptaddr = rdap->rda_preinit_addr;
108		break;
109	case RD_POSTINIT:
110		notify->type = RD_NOTIFY_BPT;
111		notify->u.bptaddr = rdap->rda_postinit_addr;
112		break;
113	case RD_DLACTIVITY:
114		notify->type = RD_NOTIFY_BPT;
115		notify->u.bptaddr = rdap->rda_dlactivity_addr;
116		break;
117	default:
118		ret = RD_ERR;
119		break;
120	}
121	return (ret);
122}
123
124rd_err_e
125rd_event_enable(rd_agent_t *rdap __unused, int onoff)
126{
127	DPRINTF("%s onoff %d\n", __func__, onoff);
128
129	return (RD_OK);
130}
131
132rd_err_e
133rd_event_getmsg(rd_agent_t *rdap __unused, rd_event_msg_t *msg)
134{
135	DPRINTF("%s\n", __func__);
136
137	msg->type = RD_POSTINIT;
138	msg->u.state = RD_CONSISTENT;
139
140	return (RD_OK);
141}
142
143rd_err_e
144rd_init(int version)
145{
146	char *debug = NULL;
147
148	if (version == RD_VERSION) {
149		debug = getenv("LIBRTLD_DB_DEBUG");
150		_librtld_db_debug = debug ? atoi(debug) : 0;
151		return (RD_OK);
152	} else
153		return (RD_NOCAPAB);
154}
155
156rd_err_e
157rd_loadobj_iter(rd_agent_t *rdap, rl_iter_f *cb, void *clnt_data)
158{
159	struct kinfo_vmentry *kves, *kve;
160	const char *path;
161	uint64_t fileid;
162	rd_loadobj_t rdl;
163	rd_err_e ret;
164	uintptr_t base;
165	uint32_t offset;
166	int cnt, i;
167
168	DPRINTF("%s\n", __func__);
169
170	if ((kves = kinfo_getvmmap(proc_getpid(rdap->rda_php), &cnt)) == NULL) {
171		warn("ERROR: kinfo_getvmmap() failed");
172		return (RD_ERR);
173	}
174
175	base = 0;
176	fileid = 0;
177	path = NULL;
178	ret = RD_OK;
179	for (i = 0; i < cnt; i++) {
180		kve = &kves[i];
181		/*
182		 * Cache the base offset of the file mapping.  The kve_offset
183		 * field gives the file offset of a particular mapping into the
184		 * file, but we want the mapping offset relative to the base
185		 * mapping.
186		 */
187		if (kve->kve_type == KVME_TYPE_VNODE) {
188			if (kve->kve_vn_fileid != fileid) {
189				base = kve->kve_start;
190				fileid = kve->kve_vn_fileid;
191			}
192			path = kve->kve_path;
193			offset = kve->kve_start - base;
194		} else {
195			path = NULL;
196			offset = 0;
197		}
198		memset(&rdl, 0, sizeof(rdl));
199		/*
200		 * Map the kinfo_vmentry struct to the rd_loadobj structure.
201		 */
202		rdl.rdl_saddr = kve->kve_start;
203		rdl.rdl_eaddr = kve->kve_end;
204		rdl.rdl_offset = offset;
205		if (kve->kve_protection & KVME_PROT_READ)
206			rdl.rdl_prot |= RD_RDL_R;
207		if (kve->kve_protection & KVME_PROT_WRITE)
208			rdl.rdl_prot |= RD_RDL_W;
209		if (kve->kve_protection & KVME_PROT_EXEC)
210			rdl.rdl_prot |= RD_RDL_X;
211		if (path != NULL)
212			strlcpy(rdl.rdl_path, path, sizeof(rdl.rdl_path));
213		if ((*cb)(&rdl, clnt_data) != 0) {
214			ret = RD_ERR;
215			break;
216		}
217	}
218	free(kves);
219	return (ret);
220}
221
222void
223rd_log(const int onoff)
224{
225	DPRINTF("%s\n", __func__);
226
227	(void)onoff;
228}
229
230rd_agent_t *
231rd_new(struct proc_handle *php)
232{
233	rd_agent_t *rdap;
234
235	rdap = malloc(sizeof(*rdap));
236	if (rdap == NULL)
237		return (NULL);
238
239	memset(rdap, 0, sizeof(rd_agent_t));
240	rdap->rda_php = php;
241	rdap->rda_procstat = procstat_open_sysctl();
242
243	if (rd_reset(rdap) != RD_OK) {
244		rd_delete(rdap);
245		rdap = NULL;
246	}
247	return (rdap);
248}
249
250rd_err_e
251rd_objpad_enable(rd_agent_t *rdap, size_t padsize)
252{
253	DPRINTF("%s\n", __func__);
254
255	(void)rdap;
256	(void)padsize;
257
258	return (RD_ERR);
259}
260
261rd_err_e
262rd_plt_resolution(rd_agent_t *rdap, uintptr_t pc, struct proc *proc,
263    uintptr_t plt_base, rd_plt_info_t *rpi)
264{
265	DPRINTF("%s\n", __func__);
266
267	(void)rdap;
268	(void)pc;
269	(void)proc;
270	(void)plt_base;
271	(void)rpi;
272
273	return (RD_ERR);
274}
275
276static int
277rtld_syms(rd_agent_t *rdap, const char *rtldpath, u_long base)
278{
279	GElf_Shdr shdr;
280	GElf_Sym sym;
281	Elf *e;
282	Elf_Data *data;
283	Elf_Scn *scn;
284	const char *symname;
285	Elf64_Word strscnidx;
286	int fd, i, ret;
287
288	ret = 1;
289	e = NULL;
290
291	fd = open(rtldpath, O_RDONLY);
292	if (fd < 0)
293		goto err;
294
295	if (elf_version(EV_CURRENT) == EV_NONE)
296		goto err;
297	e = elf_begin(fd, ELF_C_READ, NULL);
298	if (e == NULL)
299		goto err;
300
301	scn = NULL;
302	while ((scn = elf_nextscn(e, scn)) != NULL) {
303		gelf_getshdr(scn, &shdr);
304		if (shdr.sh_type == SHT_DYNSYM)
305			break;
306	}
307	if (scn == NULL)
308		goto err;
309
310	strscnidx = shdr.sh_link;
311	data = elf_getdata(scn, NULL);
312	if (data == NULL)
313		goto err;
314
315	for (i = 0; gelf_getsym(data, i, &sym) != NULL; i++) {
316		if (GELF_ST_TYPE(sym.st_info) != STT_FUNC ||
317		    GELF_ST_BIND(sym.st_info) != STB_GLOBAL)
318			continue;
319		symname = elf_strptr(e, strscnidx, sym.st_name);
320		if (symname == NULL)
321			continue;
322
323		if (strcmp(symname, "r_debug_state") == 0) {
324			rdap->rda_preinit_addr = sym.st_value + base;
325			rdap->rda_dlactivity_addr = sym.st_value + base;
326		} else if (strcmp(symname, "_r_debug_postinit") == 0) {
327			rdap->rda_postinit_addr = sym.st_value + base;
328		}
329	}
330
331	if (rdap->rda_preinit_addr != 0 &&
332	    rdap->rda_postinit_addr != 0 &&
333	    rdap->rda_dlactivity_addr != 0)
334		ret = 0;
335
336err:
337	if (e != NULL)
338		(void)elf_end(e);
339	if (fd >= 0)
340		(void)close(fd);
341	return (ret);
342}
343
344rd_err_e
345rd_reset(rd_agent_t *rdap)
346{
347	struct kinfo_proc *kp;
348	struct kinfo_vmentry *kve;
349	Elf_Auxinfo *auxv;
350	const char *rtldpath;
351	u_long base;
352	rd_err_e rderr;
353	int count, i;
354
355	kp = NULL;
356	auxv = NULL;
357	kve = NULL;
358	rderr = RD_ERR;
359
360	kp = procstat_getprocs(rdap->rda_procstat, KERN_PROC_PID,
361	    proc_getpid(rdap->rda_php), &count);
362	if (kp == NULL)
363		return (RD_ERR);
364	assert(count == 1);
365
366	auxv = procstat_getauxv(rdap->rda_procstat, kp, &count);
367	if (auxv == NULL)
368		goto err;
369
370	base = 0;
371	for (i = 0; i < count; i++) {
372		if (auxv[i].a_type == AT_BASE) {
373			base = auxv[i].a_un.a_val;
374			break;
375		}
376	}
377	if (i == count)
378		goto err;
379
380	rtldpath = NULL;
381	kve = procstat_getvmmap(rdap->rda_procstat, kp, &count);
382	if (kve == NULL)
383		goto err;
384	for (i = 0; i < count; i++) {
385		if (kve[i].kve_start == base) {
386			rtldpath = kve[i].kve_path;
387			break;
388		}
389	}
390	if (i == count)
391		goto err;
392
393	if (rtld_syms(rdap, rtldpath, base) != 0)
394		goto err;
395
396	rderr = RD_OK;
397
398err:
399	if (kve != NULL)
400		procstat_freevmmap(rdap->rda_procstat, kve);
401	if (auxv != NULL)
402		procstat_freeauxv(rdap->rda_procstat, auxv);
403	if (kp != NULL)
404		procstat_freeprocs(rdap->rda_procstat, kp);
405	return (rderr);
406}
407