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 54 static 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 62 void 63 rd_delete(rd_agent_t *rdap) 64 { 65 66 if (rdap->rda_procstat != NULL) 67 procstat_close(rdap->rda_procstat); 68 free(rdap); 69 } 70 71 const char * 72 rd_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 93 rd_err_e 94 rd_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 } 123 124 rd_err_e 125 rd_event_enable(rd_agent_t *rdap __unused, int onoff) 126 { 127 DPRINTF("%s onoff %d\n", __func__, onoff); 128 129 return (RD_OK); 130 } 131 132 rd_err_e 133 rd_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 } 142 143 rd_err_e 144 rd_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 } 155 156 rd_err_e 157 rd_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 } 221 222 void 223 rd_log(const int onoff) 224 { 225 DPRINTF("%s\n", __func__); 226 227 (void)onoff; 228 } 229 230 rd_agent_t * 231 rd_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 } 249 250 rd_err_e 251 rd_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 } 260 261 rd_err_e 262 rd_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 } 275 276 static int 277 rtld_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; 335 336 err: 337 if (e != NULL) 338 (void)elf_end(e); 339 if (fd >= 0) 340 (void)close(fd); 341 return (ret); 342 } 343 344 rd_err_e 345 rd_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; 397 398 err: 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