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/cdefs.h> 33 #include <sys/param.h> 34 #include <sys/sysctl.h> 35 #include <sys/user.h> 36 37 #include <assert.h> 38 #include <err.h> 39 #include <fcntl.h> 40 #include <limits.h> 41 #include <stdio.h> 42 #include <stdlib.h> 43 #include <string.h> 44 #include <unistd.h> 45 46 #include <machine/elf.h> 47 48 #include <libelf.h> 49 #include <libproc.h> 50 #include <libprocstat.h> 51 #include <libutil.h> 52 53 #include "rtld_db.h" 54 55 static int _librtld_db_debug = 0; 56 #define DPRINTF(...) do { \ 57 if (_librtld_db_debug) { \ 58 fprintf(stderr, "librtld_db: DEBUG: "); \ 59 fprintf(stderr, __VA_ARGS__); \ 60 } \ 61 } while (0) 62 63 void 64 rd_delete(rd_agent_t *rdap) 65 { 66 67 if (rdap->rda_procstat != NULL) 68 procstat_close(rdap->rda_procstat); 69 free(rdap); 70 } 71 72 const char * 73 rd_errstr(rd_err_e rderr) 74 { 75 76 switch (rderr) { 77 case RD_ERR: 78 return "generic error"; 79 case RD_OK: 80 return "no error"; 81 case RD_NOCAPAB: 82 return "capability not supported"; 83 case RD_DBERR: 84 return "database error"; 85 case RD_NOBASE: 86 return "NOBASE"; 87 case RD_NOMAPS: 88 return "NOMAPS"; 89 default: 90 return "unknown error"; 91 } 92 } 93 94 rd_err_e 95 rd_event_addr(rd_agent_t *rdap, rd_event_e event, rd_notify_t *notify) 96 { 97 rd_err_e ret; 98 99 DPRINTF("%s rdap %p event %d notify %p\n", __func__, rdap, event, 100 notify); 101 102 ret = RD_OK; 103 switch (event) { 104 case RD_NONE: 105 break; 106 case RD_PREINIT: 107 notify->type = RD_NOTIFY_BPT; 108 notify->u.bptaddr = rdap->rda_preinit_addr; 109 break; 110 case RD_POSTINIT: 111 notify->type = RD_NOTIFY_BPT; 112 notify->u.bptaddr = rdap->rda_postinit_addr; 113 break; 114 case RD_DLACTIVITY: 115 notify->type = RD_NOTIFY_BPT; 116 notify->u.bptaddr = rdap->rda_dlactivity_addr; 117 break; 118 default: 119 ret = RD_ERR; 120 break; 121 } 122 return (ret); 123 } 124 125 rd_err_e 126 rd_event_enable(rd_agent_t *rdap __unused, int onoff) 127 { 128 DPRINTF("%s onoff %d\n", __func__, onoff); 129 130 return (RD_OK); 131 } 132 133 rd_err_e 134 rd_event_getmsg(rd_agent_t *rdap __unused, rd_event_msg_t *msg) 135 { 136 DPRINTF("%s\n", __func__); 137 138 msg->type = RD_POSTINIT; 139 msg->u.state = RD_CONSISTENT; 140 141 return (RD_OK); 142 } 143 144 rd_err_e 145 rd_init(int version) 146 { 147 char *debug = NULL; 148 149 if (version == RD_VERSION) { 150 debug = getenv("LIBRTLD_DB_DEBUG"); 151 _librtld_db_debug = debug ? atoi(debug) : 0; 152 return (RD_OK); 153 } else 154 return (RD_NOCAPAB); 155 } 156 157 rd_err_e 158 rd_loadobj_iter(rd_agent_t *rdap, rl_iter_f *cb, void *clnt_data) 159 { 160 struct kinfo_vmentry *kves, *kve; 161 const char *path; 162 uint64_t fileid; 163 rd_loadobj_t rdl; 164 rd_err_e ret; 165 uintptr_t base; 166 uint32_t offset; 167 int cnt, i; 168 169 DPRINTF("%s\n", __func__); 170 171 if ((kves = kinfo_getvmmap(proc_getpid(rdap->rda_php), &cnt)) == NULL) { 172 warn("ERROR: kinfo_getvmmap() failed"); 173 return (RD_ERR); 174 } 175 176 base = 0; 177 fileid = 0; 178 path = NULL; 179 ret = RD_OK; 180 for (i = 0; i < cnt; i++) { 181 kve = &kves[i]; 182 /* 183 * Cache the base offset of the file mapping. The kve_offset 184 * field gives the file offset of a particular mapping into the 185 * file, but we want the mapping offset relative to the base 186 * mapping. 187 */ 188 if (kve->kve_type == KVME_TYPE_VNODE) { 189 if (kve->kve_vn_fileid != fileid) { 190 base = kve->kve_start; 191 fileid = kve->kve_vn_fileid; 192 } 193 path = kve->kve_path; 194 offset = kve->kve_start - base; 195 } else { 196 path = NULL; 197 offset = 0; 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 = offset; 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 } 222 223 void 224 rd_log(const int onoff) 225 { 226 DPRINTF("%s\n", __func__); 227 228 (void)onoff; 229 } 230 231 rd_agent_t * 232 rd_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 } 250 251 rd_err_e 252 rd_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 } 261 262 rd_err_e 263 rd_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 } 276 277 static int 278 rtld_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; 336 337 err: 338 if (e != NULL) 339 (void)elf_end(e); 340 if (fd >= 0) 341 (void)close(fd); 342 return (ret); 343 } 344 345 rd_err_e 346 rd_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; 398 399 err: 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