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