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 __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 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 * 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 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 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 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 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 160 rd_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 uint32_t offset; 169 int cnt, i; 170 171 DPRINTF("%s\n", __func__); 172 173 if ((kves = kinfo_getvmmap(proc_getpid(rdap->rda_php), &cnt)) == NULL) { 174 warn("ERROR: kinfo_getvmmap() failed"); 175 return (RD_ERR); 176 } 177 178 base = 0; 179 fileid = 0; 180 path = NULL; 181 ret = RD_OK; 182 for (i = 0; i < cnt; i++) { 183 kve = &kves[i]; 184 /* 185 * Cache the base offset of the file mapping. The kve_offset 186 * field gives the file offset of a particular mapping into the 187 * file, but we want the mapping offset relative to the base 188 * mapping. 189 */ 190 if (kve->kve_type == KVME_TYPE_VNODE) { 191 if (kve->kve_vn_fileid != fileid) { 192 base = kve->kve_start; 193 fileid = kve->kve_vn_fileid; 194 } 195 path = kve->kve_path; 196 offset = kve->kve_start - base; 197 } else { 198 path = NULL; 199 offset = 0; 200 } 201 memset(&rdl, 0, sizeof(rdl)); 202 /* 203 * Map the kinfo_vmentry struct to the rd_loadobj structure. 204 */ 205 rdl.rdl_saddr = kve->kve_start; 206 rdl.rdl_eaddr = kve->kve_end; 207 rdl.rdl_offset = offset; 208 if (kve->kve_protection & KVME_PROT_READ) 209 rdl.rdl_prot |= RD_RDL_R; 210 if (kve->kve_protection & KVME_PROT_WRITE) 211 rdl.rdl_prot |= RD_RDL_W; 212 if (kve->kve_protection & KVME_PROT_EXEC) 213 rdl.rdl_prot |= RD_RDL_X; 214 if (path != NULL) 215 strlcpy(rdl.rdl_path, path, sizeof(rdl.rdl_path)); 216 if ((*cb)(&rdl, clnt_data) != 0) { 217 ret = RD_ERR; 218 break; 219 } 220 } 221 free(kves); 222 return (ret); 223 } 224 225 void 226 rd_log(const int onoff) 227 { 228 DPRINTF("%s\n", __func__); 229 230 (void)onoff; 231 } 232 233 rd_agent_t * 234 rd_new(struct proc_handle *php) 235 { 236 rd_agent_t *rdap; 237 238 rdap = malloc(sizeof(*rdap)); 239 if (rdap == NULL) 240 return (NULL); 241 242 memset(rdap, 0, sizeof(rd_agent_t)); 243 rdap->rda_php = php; 244 rdap->rda_procstat = procstat_open_sysctl(); 245 246 if (rd_reset(rdap) != RD_OK) { 247 rd_delete(rdap); 248 rdap = NULL; 249 } 250 return (rdap); 251 } 252 253 rd_err_e 254 rd_objpad_enable(rd_agent_t *rdap, size_t padsize) 255 { 256 DPRINTF("%s\n", __func__); 257 258 (void)rdap; 259 (void)padsize; 260 261 return (RD_ERR); 262 } 263 264 rd_err_e 265 rd_plt_resolution(rd_agent_t *rdap, uintptr_t pc, struct proc *proc, 266 uintptr_t plt_base, rd_plt_info_t *rpi) 267 { 268 DPRINTF("%s\n", __func__); 269 270 (void)rdap; 271 (void)pc; 272 (void)proc; 273 (void)plt_base; 274 (void)rpi; 275 276 return (RD_ERR); 277 } 278 279 static int 280 rtld_syms(rd_agent_t *rdap, const char *rtldpath, u_long base) 281 { 282 GElf_Shdr shdr; 283 GElf_Sym sym; 284 Elf *e; 285 Elf_Data *data; 286 Elf_Scn *scn; 287 const char *symname; 288 Elf64_Word strscnidx; 289 int fd, i, ret; 290 291 ret = 1; 292 e = NULL; 293 294 fd = open(rtldpath, O_RDONLY); 295 if (fd < 0) 296 goto err; 297 298 if (elf_version(EV_CURRENT) == EV_NONE) 299 goto err; 300 e = elf_begin(fd, ELF_C_READ, NULL); 301 if (e == NULL) 302 goto err; 303 304 scn = NULL; 305 while ((scn = elf_nextscn(e, scn)) != NULL) { 306 gelf_getshdr(scn, &shdr); 307 if (shdr.sh_type == SHT_DYNSYM) 308 break; 309 } 310 if (scn == NULL) 311 goto err; 312 313 strscnidx = shdr.sh_link; 314 data = elf_getdata(scn, NULL); 315 if (data == NULL) 316 goto err; 317 318 for (i = 0; gelf_getsym(data, i, &sym) != NULL; i++) { 319 if (GELF_ST_TYPE(sym.st_info) != STT_FUNC || 320 GELF_ST_BIND(sym.st_info) != STB_GLOBAL) 321 continue; 322 symname = elf_strptr(e, strscnidx, sym.st_name); 323 if (symname == NULL) 324 continue; 325 326 if (strcmp(symname, "r_debug_state") == 0) { 327 rdap->rda_preinit_addr = sym.st_value + base; 328 rdap->rda_dlactivity_addr = sym.st_value + base; 329 } else if (strcmp(symname, "_r_debug_postinit") == 0) { 330 rdap->rda_postinit_addr = sym.st_value + base; 331 } 332 } 333 334 if (rdap->rda_preinit_addr != 0 && 335 rdap->rda_postinit_addr != 0 && 336 rdap->rda_dlactivity_addr != 0) 337 ret = 0; 338 339 err: 340 if (e != NULL) 341 (void)elf_end(e); 342 if (fd >= 0) 343 (void)close(fd); 344 return (ret); 345 } 346 347 rd_err_e 348 rd_reset(rd_agent_t *rdap) 349 { 350 struct kinfo_proc *kp; 351 struct kinfo_vmentry *kve; 352 Elf_Auxinfo *auxv; 353 const char *rtldpath; 354 u_long base; 355 rd_err_e rderr; 356 int count, i; 357 358 kp = NULL; 359 auxv = NULL; 360 kve = NULL; 361 rderr = RD_ERR; 362 363 kp = procstat_getprocs(rdap->rda_procstat, KERN_PROC_PID, 364 proc_getpid(rdap->rda_php), &count); 365 if (kp == NULL) 366 return (RD_ERR); 367 assert(count == 1); 368 369 auxv = procstat_getauxv(rdap->rda_procstat, kp, &count); 370 if (auxv == NULL) 371 goto err; 372 373 base = 0; 374 for (i = 0; i < count; i++) { 375 if (auxv[i].a_type == AT_BASE) { 376 base = auxv[i].a_un.a_val; 377 break; 378 } 379 } 380 if (i == count) 381 goto err; 382 383 rtldpath = NULL; 384 kve = procstat_getvmmap(rdap->rda_procstat, kp, &count); 385 if (kve == NULL) 386 goto err; 387 for (i = 0; i < count; i++) { 388 if (kve[i].kve_start == base) { 389 rtldpath = kve[i].kve_path; 390 break; 391 } 392 } 393 if (i == count) 394 goto err; 395 396 if (rtld_syms(rdap, rtldpath, base) != 0) 397 goto err; 398 399 rderr = RD_OK; 400 401 err: 402 if (kve != NULL) 403 procstat_freevmmap(rdap->rda_procstat, kve); 404 if (auxv != NULL) 405 procstat_freeauxv(rdap->rda_procstat, auxv); 406 if (kp != NULL) 407 procstat_freeprocs(rdap->rda_procstat, kp); 408 return (rderr); 409 } 410