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
32#include <sys/cdefs.h>
33__FBSDID("$FreeBSD$");
34
35#include <sys/param.h>
36#include <sys/sysctl.h>
37#include <sys/user.h>
38
39#include <assert.h>
40#include <err.h>
41#include <fcntl.h>
42#include <limits.h>
43#include <stdio.h>
44#include <stdlib.h>
45#include <string.h>
46#include <unistd.h>
47
48#include <machine/elf.h>
49
50#include <libelf.h>
51#include <libproc.h>
52#include <libprocstat.h>
53#include <libutil.h>
54
55#include "rtld_db.h"
56
57static int _librtld_db_debug = 0;
58#define DPRINTF(...) do {				\
59	if (_librtld_db_debug) {			\
60		fprintf(stderr, "librtld_db: DEBUG: ");	\
61		fprintf(stderr, __VA_ARGS__);		\
62	}						\
63} while (0)
64
65void
66rd_delete(rd_agent_t *rdap)
67{
68
69	if (rdap->rda_procstat != NULL)
70		procstat_close(rdap->rda_procstat);
71	free(rdap);
72}
73
74const char *
75rd_errstr(rd_err_e rderr)
76{
77
78	switch (rderr) {
79	case RD_ERR:
80		return "generic error";
81	case RD_OK:
82		return "no error";
83	case RD_NOCAPAB:
84		return "capability not supported";
85	case RD_DBERR:
86		return "database error";
87	case RD_NOBASE:
88		return "NOBASE";
89	case RD_NOMAPS:
90		return "NOMAPS";
91	default:
92		return "unknown error";
93	}
94}
95
96rd_err_e
97rd_event_addr(rd_agent_t *rdap, rd_event_e event, rd_notify_t *notify)
98{
99	rd_err_e ret;
100
101	DPRINTF("%s rdap %p event %d notify %p\n", __func__, rdap, event,
102	    notify);
103
104	ret = RD_OK;
105	switch (event) {
106	case RD_NONE:
107		break;
108	case RD_PREINIT:
109		notify->type = RD_NOTIFY_BPT;
110		notify->u.bptaddr = rdap->rda_preinit_addr;
111		break;
112	case RD_POSTINIT:
113		notify->type = RD_NOTIFY_BPT;
114		notify->u.bptaddr = rdap->rda_postinit_addr;
115		break;
116	case RD_DLACTIVITY:
117		notify->type = RD_NOTIFY_BPT;
118		notify->u.bptaddr = rdap->rda_dlactivity_addr;
119		break;
120	default:
121		ret = RD_ERR;
122		break;
123	}
124	return (ret);
125}
126
127rd_err_e
128rd_event_enable(rd_agent_t *rdap __unused, int onoff)
129{
130	DPRINTF("%s onoff %d\n", __func__, onoff);
131
132	return (RD_OK);
133}
134
135rd_err_e
136rd_event_getmsg(rd_agent_t *rdap __unused, rd_event_msg_t *msg)
137{
138	DPRINTF("%s\n", __func__);
139
140	msg->type = RD_POSTINIT;
141	msg->u.state = RD_CONSISTENT;
142
143	return (RD_OK);
144}
145
146rd_err_e
147rd_init(int version)
148{
149	char *debug = NULL;
150
151	if (version == RD_VERSION) {
152		debug = getenv("LIBRTLD_DB_DEBUG");
153		_librtld_db_debug = debug ? atoi(debug) : 0;
154		return (RD_OK);
155	} else
156		return (RD_NOCAPAB);
157}
158
159rd_err_e
160rd_loadobj_iter(rd_agent_t *rdap, rl_iter_f *cb, void *clnt_data)
161{
162	struct kinfo_vmentry *kves, *kve;
163	const char *path;
164	uint64_t fileid;
165	rd_loadobj_t rdl;
166	rd_err_e ret;
167	uintptr_t base;
168	int cnt, i;
169
170	DPRINTF("%s\n", __func__);
171
172	if ((kves = kinfo_getvmmap(proc_getpid(rdap->rda_php), &cnt)) == NULL) {
173		warn("ERROR: kinfo_getvmmap() failed");
174		return (RD_ERR);
175	}
176
177	base = 0;
178	fileid = 0;
179	path = NULL;
180	ret = RD_OK;
181	for (i = 0; i < cnt; i++) {
182		kve = &kves[i];
183		/*
184		 * Cache the base offset of the file mapping.  The kve_offset
185		 * field gives the file offset of a particular mapping into the
186		 * file, but we want the mapping offset relative to the base
187		 * mapping.
188		 */
189		if (kve->kve_type == KVME_TYPE_VNODE) {
190			if (kve->kve_vn_fileid != fileid) {
191				base = kve->kve_start;
192				fileid = kve->kve_vn_fileid;
193				path = kve->kve_path;
194			}
195		} else {
196			base = 0;
197			path = NULL;
198		}
199		memset(&rdl, 0, sizeof(rdl));
200		/*
201		 * Map the kinfo_vmentry struct to the rd_loadobj structure.
202		 */
203		rdl.rdl_saddr = kve->kve_start;
204		rdl.rdl_eaddr = kve->kve_end;
205		rdl.rdl_offset = kve->kve_start - base;
206		if (kve->kve_protection & KVME_PROT_READ)
207			rdl.rdl_prot |= RD_RDL_R;
208		if (kve->kve_protection & KVME_PROT_WRITE)
209			rdl.rdl_prot |= RD_RDL_W;
210		if (kve->kve_protection & KVME_PROT_EXEC)
211			rdl.rdl_prot |= RD_RDL_X;
212		if (path != NULL)
213			strlcpy(rdl.rdl_path, path, sizeof(rdl.rdl_path));
214		if ((*cb)(&rdl, clnt_data) != 0) {
215			ret = RD_ERR;
216			break;
217		}
218	}
219	free(kves);
220	return (ret);
221}
222
223void
224rd_log(const int onoff)
225{
226	DPRINTF("%s\n", __func__);
227
228	(void)onoff;
229}
230
231rd_agent_t *
232rd_new(struct proc_handle *php)
233{
234	rd_agent_t *rdap;
235
236	rdap = malloc(sizeof(*rdap));
237	if (rdap == NULL)
238		return (NULL);
239
240	memset(rdap, 0, sizeof(rd_agent_t));
241	rdap->rda_php = php;
242	rdap->rda_procstat = procstat_open_sysctl();
243
244	if (rd_reset(rdap) != RD_OK) {
245		rd_delete(rdap);
246		rdap = NULL;
247	}
248	return (rdap);
249}
250
251rd_err_e
252rd_objpad_enable(rd_agent_t *rdap, size_t padsize)
253{
254	DPRINTF("%s\n", __func__);
255
256	(void)rdap;
257	(void)padsize;
258
259	return (RD_ERR);
260}
261
262rd_err_e
263rd_plt_resolution(rd_agent_t *rdap, uintptr_t pc, struct proc *proc,
264    uintptr_t plt_base, rd_plt_info_t *rpi)
265{
266	DPRINTF("%s\n", __func__);
267
268	(void)rdap;
269	(void)pc;
270	(void)proc;
271	(void)plt_base;
272	(void)rpi;
273
274	return (RD_ERR);
275}
276
277static int
278rtld_syms(rd_agent_t *rdap, const char *rtldpath, u_long base)
279{
280	GElf_Shdr shdr;
281	GElf_Sym sym;
282	Elf *e;
283	Elf_Data *data;
284	Elf_Scn *scn;
285	const char *symname;
286	Elf64_Word strscnidx;
287	int fd, i, ret;
288
289	ret = 1;
290	e = NULL;
291
292	fd = open(rtldpath, O_RDONLY);
293	if (fd < 0)
294		goto err;
295
296	if (elf_version(EV_CURRENT) == EV_NONE)
297		goto err;
298	e = elf_begin(fd, ELF_C_READ, NULL);
299	if (e == NULL)
300		goto err;
301
302	scn = NULL;
303	while ((scn = elf_nextscn(e, scn)) != NULL) {
304		gelf_getshdr(scn, &shdr);
305		if (shdr.sh_type == SHT_DYNSYM)
306			break;
307	}
308	if (scn == NULL)
309		goto err;
310
311	strscnidx = shdr.sh_link;
312	data = elf_getdata(scn, NULL);
313	if (data == NULL)
314		goto err;
315
316	for (i = 0; gelf_getsym(data, i, &sym) != NULL; i++) {
317		if (GELF_ST_TYPE(sym.st_info) != STT_FUNC ||
318		    GELF_ST_BIND(sym.st_info) != STB_GLOBAL)
319			continue;
320		symname = elf_strptr(e, strscnidx, sym.st_name);
321		if (symname == NULL)
322			continue;
323
324		if (strcmp(symname, "r_debug_state") == 0) {
325			rdap->rda_preinit_addr = sym.st_value + base;
326			rdap->rda_dlactivity_addr = sym.st_value + base;
327		} else if (strcmp(symname, "_r_debug_postinit") == 0) {
328			rdap->rda_postinit_addr = sym.st_value + base;
329		}
330	}
331
332	if (rdap->rda_preinit_addr != 0 &&
333	    rdap->rda_postinit_addr != 0 &&
334	    rdap->rda_dlactivity_addr != 0)
335		ret = 0;
336
337err:
338	if (e != NULL)
339		(void)elf_end(e);
340	if (fd >= 0)
341		(void)close(fd);
342	return (ret);
343}
344
345rd_err_e
346rd_reset(rd_agent_t *rdap)
347{
348	struct kinfo_proc *kp;
349	struct kinfo_vmentry *kve;
350	Elf_Auxinfo *auxv;
351	const char *rtldpath;
352	u_long base;
353	rd_err_e rderr;
354	int count, i;
355
356	kp = NULL;
357	auxv = NULL;
358	kve = NULL;
359	rderr = RD_ERR;
360
361	kp = procstat_getprocs(rdap->rda_procstat, KERN_PROC_PID,
362	    proc_getpid(rdap->rda_php), &count);
363	if (kp == NULL)
364		return (RD_ERR);
365	assert(count == 1);
366
367	auxv = procstat_getauxv(rdap->rda_procstat, kp, &count);
368	if (auxv == NULL)
369		goto err;
370
371	base = 0;
372	for (i = 0; i < count; i++) {
373		if (auxv[i].a_type == AT_BASE) {
374			base = auxv[i].a_un.a_val;
375			break;
376		}
377	}
378	if (i == count)
379		goto err;
380
381	rtldpath = NULL;
382	kve = procstat_getvmmap(rdap->rda_procstat, kp, &count);
383	if (kve == NULL)
384		goto err;
385	for (i = 0; i < count; i++) {
386		if (kve[i].kve_start == base) {
387			rtldpath = kve[i].kve_path;
388			break;
389		}
390	}
391	if (i == count)
392		goto err;
393
394	if (rtld_syms(rdap, rtldpath, base) != 0)
395		goto err;
396
397	rderr = RD_OK;
398
399err:
400	if (kve != NULL)
401		procstat_freevmmap(rdap->rda_procstat, kve);
402	if (auxv != NULL)
403		procstat_freeauxv(rdap->rda_procstat, auxv);
404	if (kp != NULL)
405		procstat_freeprocs(rdap->rda_procstat, kp);
406	return (rderr);
407}
408