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
57 static 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
65 void
rd_delete(rd_agent_t * rdap)66 rd_delete(rd_agent_t *rdap)
67 {
68
69 if (rdap->rda_procstat != NULL)
70 procstat_close(rdap->rda_procstat);
71 free(rdap);
72 }
73
74 const char *
rd_errstr(rd_err_e rderr)75 rd_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
96 rd_err_e
rd_event_addr(rd_agent_t * rdap,rd_event_e event,rd_notify_t * notify)97 rd_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
127 rd_err_e
rd_event_enable(rd_agent_t * rdap __unused,int onoff)128 rd_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
135 rd_err_e
rd_event_getmsg(rd_agent_t * rdap __unused,rd_event_msg_t * msg)136 rd_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
146 rd_err_e
rd_init(int version)147 rd_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
159 rd_err_e
rd_loadobj_iter(rd_agent_t * rdap,rl_iter_f * cb,void * clnt_data)160 rd_loadobj_iter(rd_agent_t *rdap, rl_iter_f *cb, void *clnt_data)
161 {
162 struct kinfo_vmentry *kves, *kve;
163 rd_loadobj_t rdl;
164 rd_err_e ret;
165 int cnt, i, lastvn;
166
167 DPRINTF("%s\n", __func__);
168
169 if ((kves = kinfo_getvmmap(proc_getpid(rdap->rda_php), &cnt)) == NULL) {
170 warn("ERROR: kinfo_getvmmap() failed");
171 return (RD_ERR);
172 }
173
174 ret = RD_OK;
175 lastvn = 0;
176 for (i = 0; i < cnt; i++) {
177 kve = kves + i;
178 if (kve->kve_type == KVME_TYPE_VNODE)
179 lastvn = i;
180 memset(&rdl, 0, sizeof(rdl));
181 /*
182 * Map the kinfo_vmentry struct to the rd_loadobj structure.
183 */
184 rdl.rdl_saddr = kve->kve_start;
185 rdl.rdl_eaddr = kve->kve_end;
186 rdl.rdl_offset = kve->kve_offset;
187 if (kve->kve_protection & KVME_PROT_READ)
188 rdl.rdl_prot |= RD_RDL_R;
189 if (kve->kve_protection & KVME_PROT_WRITE)
190 rdl.rdl_prot |= RD_RDL_W;
191 if (kve->kve_protection & KVME_PROT_EXEC)
192 rdl.rdl_prot |= RD_RDL_X;
193 strlcpy(rdl.rdl_path, kves[lastvn].kve_path,
194 sizeof(rdl.rdl_path));
195 if ((*cb)(&rdl, clnt_data) != 0) {
196 ret = RD_ERR;
197 break;
198 }
199 }
200 free(kves);
201 return (ret);
202 }
203
204 void
rd_log(const int onoff)205 rd_log(const int onoff)
206 {
207 DPRINTF("%s\n", __func__);
208
209 (void)onoff;
210 }
211
212 rd_agent_t *
rd_new(struct proc_handle * php)213 rd_new(struct proc_handle *php)
214 {
215 rd_agent_t *rdap;
216
217 rdap = malloc(sizeof(*rdap));
218 if (rdap == NULL)
219 return (NULL);
220
221 memset(rdap, 0, sizeof(rd_agent_t));
222 rdap->rda_php = php;
223 rdap->rda_procstat = procstat_open_sysctl();
224
225 if (rd_reset(rdap) != RD_OK) {
226 rd_delete(rdap);
227 rdap = NULL;
228 }
229 return (rdap);
230 }
231
232 rd_err_e
rd_objpad_enable(rd_agent_t * rdap,size_t padsize)233 rd_objpad_enable(rd_agent_t *rdap, size_t padsize)
234 {
235 DPRINTF("%s\n", __func__);
236
237 (void)rdap;
238 (void)padsize;
239
240 return (RD_ERR);
241 }
242
243 rd_err_e
rd_plt_resolution(rd_agent_t * rdap,uintptr_t pc,struct proc * proc,uintptr_t plt_base,rd_plt_info_t * rpi)244 rd_plt_resolution(rd_agent_t *rdap, uintptr_t pc, struct proc *proc,
245 uintptr_t plt_base, rd_plt_info_t *rpi)
246 {
247 DPRINTF("%s\n", __func__);
248
249 (void)rdap;
250 (void)pc;
251 (void)proc;
252 (void)plt_base;
253 (void)rpi;
254
255 return (RD_ERR);
256 }
257
258 static int
rtld_syms(rd_agent_t * rdap,const char * rtldpath,u_long base)259 rtld_syms(rd_agent_t *rdap, const char *rtldpath, u_long base)
260 {
261 GElf_Shdr shdr;
262 GElf_Sym sym;
263 Elf *e;
264 Elf_Data *data;
265 Elf_Scn *scn;
266 const char *symname;
267 Elf64_Word strscnidx;
268 int fd, i, ret;
269
270 ret = 1;
271 e = NULL;
272
273 fd = open(rtldpath, O_RDONLY);
274 if (fd < 0)
275 goto err;
276
277 if (elf_version(EV_CURRENT) == EV_NONE)
278 goto err;
279 e = elf_begin(fd, ELF_C_READ, NULL);
280 if (e == NULL)
281 goto err;
282
283 scn = NULL;
284 while ((scn = elf_nextscn(e, scn)) != NULL) {
285 gelf_getshdr(scn, &shdr);
286 if (shdr.sh_type == SHT_DYNSYM)
287 break;
288 }
289 if (scn == NULL)
290 goto err;
291
292 strscnidx = shdr.sh_link;
293 data = elf_getdata(scn, NULL);
294 if (data == NULL)
295 goto err;
296
297 for (i = 0; gelf_getsym(data, i, &sym) != NULL; i++) {
298 if (GELF_ST_TYPE(sym.st_info) != STT_FUNC ||
299 GELF_ST_BIND(sym.st_info) != STB_GLOBAL)
300 continue;
301 symname = elf_strptr(e, strscnidx, sym.st_name);
302 if (symname == NULL)
303 continue;
304
305 if (strcmp(symname, "r_debug_state") == 0) {
306 rdap->rda_preinit_addr = sym.st_value + base;
307 rdap->rda_dlactivity_addr = sym.st_value + base;
308 } else if (strcmp(symname, "_r_debug_postinit") == 0) {
309 rdap->rda_postinit_addr = sym.st_value + base;
310 }
311 }
312
313 if (rdap->rda_preinit_addr != 0 &&
314 rdap->rda_postinit_addr != 0 &&
315 rdap->rda_dlactivity_addr != 0)
316 ret = 0;
317
318 err:
319 if (e != NULL)
320 (void)elf_end(e);
321 if (fd >= 0)
322 (void)close(fd);
323 return (ret);
324 }
325
326 rd_err_e
rd_reset(rd_agent_t * rdap)327 rd_reset(rd_agent_t *rdap)
328 {
329 struct kinfo_proc *kp;
330 struct kinfo_vmentry *kve;
331 Elf_Auxinfo *auxv;
332 const char *rtldpath;
333 u_long base;
334 rd_err_e rderr;
335 int count, i;
336
337 kp = NULL;
338 auxv = NULL;
339 kve = NULL;
340 rderr = RD_ERR;
341
342 kp = procstat_getprocs(rdap->rda_procstat, KERN_PROC_PID,
343 proc_getpid(rdap->rda_php), &count);
344 if (kp == NULL)
345 return (RD_ERR);
346 assert(count == 1);
347
348 auxv = procstat_getauxv(rdap->rda_procstat, kp, &count);
349 if (auxv == NULL)
350 goto err;
351
352 base = 0;
353 for (i = 0; i < count; i++) {
354 if (auxv[i].a_type == AT_BASE) {
355 base = auxv[i].a_un.a_val;
356 break;
357 }
358 }
359 if (i == count)
360 goto err;
361
362 rtldpath = NULL;
363 kve = procstat_getvmmap(rdap->rda_procstat, kp, &count);
364 if (kve == NULL)
365 goto err;
366 for (i = 0; i < count; i++) {
367 if (kve[i].kve_start == base) {
368 rtldpath = kve[i].kve_path;
369 break;
370 }
371 }
372 if (i == count)
373 goto err;
374
375 if (rtld_syms(rdap, rtldpath, base) != 0)
376 goto err;
377
378 rderr = RD_OK;
379
380 err:
381 if (kve != NULL)
382 procstat_freevmmap(rdap->rda_procstat, kve);
383 if (auxv != NULL)
384 procstat_freeauxv(rdap->rda_procstat, auxv);
385 if (kp != NULL)
386 procstat_freeprocs(rdap->rda_procstat, kp);
387 return (rderr);
388 }
389