1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2010 The FreeBSD Foundation 5 * 6 * This software was developed by Rui Paulo under sponsorship from the 7 * FreeBSD Foundation. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 */ 30 31 #include <sys/param.h> 32 #include <sys/sysctl.h> 33 #include <sys/user.h> 34 35 #include <assert.h> 36 #include <err.h> 37 #include <fcntl.h> 38 #include <limits.h> 39 #include <stdio.h> 40 #include <stdlib.h> 41 #include <string.h> 42 #include <unistd.h> 43 44 #include <machine/elf.h> 45 46 #include <libelf.h> 47 #include <libproc.h> 48 #include <libprocstat.h> 49 #include <libutil.h> 50 51 #include "rtld_db.h" 52 53 static int _librtld_db_debug = 0; 54 #define DPRINTF(...) do { \ 55 if (_librtld_db_debug) { \ 56 fprintf(stderr, "librtld_db: DEBUG: "); \ 57 fprintf(stderr, __VA_ARGS__); \ 58 } \ 59 } while (0) 60 61 void 62 rd_delete(rd_agent_t *rdap) 63 { 64 65 if (rdap->rda_procstat != NULL) 66 procstat_close(rdap->rda_procstat); 67 free(rdap); 68 } 69 70 const char * 71 rd_errstr(rd_err_e rderr) 72 { 73 74 switch (rderr) { 75 case RD_ERR: 76 return "generic error"; 77 case RD_OK: 78 return "no error"; 79 case RD_NOCAPAB: 80 return "capability not supported"; 81 case RD_DBERR: 82 return "database error"; 83 case RD_NOBASE: 84 return "NOBASE"; 85 case RD_NOMAPS: 86 return "NOMAPS"; 87 default: 88 return "unknown error"; 89 } 90 } 91 92 rd_err_e 93 rd_event_addr(rd_agent_t *rdap, rd_event_e event, rd_notify_t *notify) 94 { 95 rd_err_e ret; 96 97 DPRINTF("%s rdap %p event %d notify %p\n", __func__, rdap, event, 98 notify); 99 100 ret = RD_OK; 101 switch (event) { 102 case RD_NONE: 103 break; 104 case RD_PREINIT: 105 notify->type = RD_NOTIFY_BPT; 106 notify->u.bptaddr = rdap->rda_preinit_addr; 107 break; 108 case RD_POSTINIT: 109 notify->type = RD_NOTIFY_BPT; 110 notify->u.bptaddr = rdap->rda_postinit_addr; 111 break; 112 case RD_DLACTIVITY: 113 notify->type = RD_NOTIFY_BPT; 114 notify->u.bptaddr = rdap->rda_dlactivity_addr; 115 break; 116 default: 117 ret = RD_ERR; 118 break; 119 } 120 return (ret); 121 } 122 123 rd_err_e 124 rd_event_enable(rd_agent_t *rdap __unused, int onoff) 125 { 126 DPRINTF("%s onoff %d\n", __func__, onoff); 127 128 return (RD_OK); 129 } 130 131 rd_err_e 132 rd_event_getmsg(rd_agent_t *rdap __unused, rd_event_msg_t *msg) 133 { 134 DPRINTF("%s\n", __func__); 135 136 msg->type = RD_POSTINIT; 137 msg->u.state = RD_CONSISTENT; 138 139 return (RD_OK); 140 } 141 142 rd_err_e 143 rd_init(int version) 144 { 145 char *debug = NULL; 146 147 if (version == RD_VERSION) { 148 debug = getenv("LIBRTLD_DB_DEBUG"); 149 _librtld_db_debug = debug ? atoi(debug) : 0; 150 return (RD_OK); 151 } else 152 return (RD_NOCAPAB); 153 } 154 155 rd_err_e 156 rd_loadobj_iter(rd_agent_t *rdap, rl_iter_f *cb, void *clnt_data) 157 { 158 struct kinfo_vmentry *kves, *kve; 159 const char *path; 160 uint64_t fileid; 161 rd_loadobj_t rdl; 162 rd_err_e ret; 163 uintptr_t base; 164 uint32_t offset; 165 int cnt, i; 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 base = 0; 175 fileid = 0; 176 path = NULL; 177 ret = RD_OK; 178 for (i = 0; i < cnt; i++) { 179 kve = &kves[i]; 180 /* 181 * Cache the base offset of the file mapping. The kve_offset 182 * field gives the file offset of a particular mapping into the 183 * file, but we want the mapping offset relative to the base 184 * mapping. 185 */ 186 if (kve->kve_type == KVME_TYPE_VNODE) { 187 if (kve->kve_vn_fileid != fileid) { 188 base = kve->kve_start; 189 fileid = kve->kve_vn_fileid; 190 } 191 path = kve->kve_path; 192 offset = kve->kve_start - base; 193 } else { 194 path = NULL; 195 offset = 0; 196 } 197 memset(&rdl, 0, sizeof(rdl)); 198 /* 199 * Map the kinfo_vmentry struct to the rd_loadobj structure. 200 */ 201 rdl.rdl_saddr = kve->kve_start; 202 rdl.rdl_eaddr = kve->kve_end; 203 rdl.rdl_offset = offset; 204 if (kve->kve_protection & KVME_PROT_READ) 205 rdl.rdl_prot |= RD_RDL_R; 206 if (kve->kve_protection & KVME_PROT_WRITE) 207 rdl.rdl_prot |= RD_RDL_W; 208 if (kve->kve_protection & KVME_PROT_EXEC) 209 rdl.rdl_prot |= RD_RDL_X; 210 if (path != NULL) 211 strlcpy(rdl.rdl_path, path, sizeof(rdl.rdl_path)); 212 if ((*cb)(&rdl, clnt_data) != 0) { 213 ret = RD_ERR; 214 break; 215 } 216 } 217 free(kves); 218 return (ret); 219 } 220 221 void 222 rd_log(const int onoff) 223 { 224 DPRINTF("%s\n", __func__); 225 226 (void)onoff; 227 } 228 229 rd_agent_t * 230 rd_new(struct proc_handle *php) 231 { 232 rd_agent_t *rdap; 233 234 rdap = malloc(sizeof(*rdap)); 235 if (rdap == NULL) 236 return (NULL); 237 238 memset(rdap, 0, sizeof(rd_agent_t)); 239 rdap->rda_php = php; 240 rdap->rda_procstat = procstat_open_sysctl(); 241 242 if (rd_reset(rdap) != RD_OK) { 243 rd_delete(rdap); 244 rdap = NULL; 245 } 246 return (rdap); 247 } 248 249 rd_err_e 250 rd_objpad_enable(rd_agent_t *rdap, size_t padsize) 251 { 252 DPRINTF("%s\n", __func__); 253 254 (void)rdap; 255 (void)padsize; 256 257 return (RD_ERR); 258 } 259 260 rd_err_e 261 rd_plt_resolution(rd_agent_t *rdap, uintptr_t pc, struct proc *proc, 262 uintptr_t plt_base, rd_plt_info_t *rpi) 263 { 264 DPRINTF("%s\n", __func__); 265 266 (void)rdap; 267 (void)pc; 268 (void)proc; 269 (void)plt_base; 270 (void)rpi; 271 272 return (RD_ERR); 273 } 274 275 static int 276 rtld_syms(rd_agent_t *rdap, const char *rtldpath, u_long base) 277 { 278 GElf_Shdr shdr; 279 GElf_Sym sym; 280 Elf *e; 281 Elf_Data *data; 282 Elf_Scn *scn; 283 const char *symname; 284 Elf64_Word strscnidx; 285 int fd, i, ret; 286 287 ret = 1; 288 e = NULL; 289 290 fd = open(rtldpath, O_RDONLY); 291 if (fd < 0) 292 goto err; 293 294 if (elf_version(EV_CURRENT) == EV_NONE) 295 goto err; 296 e = elf_begin(fd, ELF_C_READ, NULL); 297 if (e == NULL) 298 goto err; 299 300 scn = NULL; 301 while ((scn = elf_nextscn(e, scn)) != NULL) { 302 gelf_getshdr(scn, &shdr); 303 if (shdr.sh_type == SHT_DYNSYM) 304 break; 305 } 306 if (scn == NULL) 307 goto err; 308 309 strscnidx = shdr.sh_link; 310 data = elf_getdata(scn, NULL); 311 if (data == NULL) 312 goto err; 313 314 for (i = 0; gelf_getsym(data, i, &sym) != NULL; i++) { 315 if (GELF_ST_TYPE(sym.st_info) != STT_FUNC || 316 GELF_ST_BIND(sym.st_info) != STB_GLOBAL) 317 continue; 318 symname = elf_strptr(e, strscnidx, sym.st_name); 319 if (symname == NULL) 320 continue; 321 322 if (strcmp(symname, "r_debug_state") == 0) { 323 rdap->rda_preinit_addr = sym.st_value + base; 324 rdap->rda_dlactivity_addr = sym.st_value + base; 325 } else if (strcmp(symname, "_r_debug_postinit") == 0) { 326 rdap->rda_postinit_addr = sym.st_value + base; 327 } 328 } 329 330 if (rdap->rda_preinit_addr != 0 && 331 rdap->rda_postinit_addr != 0 && 332 rdap->rda_dlactivity_addr != 0) 333 ret = 0; 334 335 err: 336 if (e != NULL) 337 (void)elf_end(e); 338 if (fd >= 0) 339 (void)close(fd); 340 return (ret); 341 } 342 343 rd_err_e 344 rd_reset(rd_agent_t *rdap) 345 { 346 struct kinfo_proc *kp; 347 struct kinfo_vmentry *kve; 348 Elf_Auxinfo *auxv; 349 const char *rtldpath; 350 u_long base; 351 rd_err_e rderr; 352 int count, i; 353 354 kp = NULL; 355 auxv = NULL; 356 kve = NULL; 357 rderr = RD_ERR; 358 359 kp = procstat_getprocs(rdap->rda_procstat, KERN_PROC_PID, 360 proc_getpid(rdap->rda_php), &count); 361 if (kp == NULL) 362 return (RD_ERR); 363 assert(count == 1); 364 365 auxv = procstat_getauxv(rdap->rda_procstat, kp, &count); 366 if (auxv == NULL) 367 goto err; 368 369 base = 0; 370 for (i = 0; i < count; i++) { 371 if (auxv[i].a_type == AT_BASE) { 372 base = auxv[i].a_un.a_val; 373 break; 374 } 375 } 376 if (i == count) 377 goto err; 378 379 rtldpath = NULL; 380 kve = procstat_getvmmap(rdap->rda_procstat, kp, &count); 381 if (kve == NULL) 382 goto err; 383 for (i = 0; i < count; i++) { 384 if (kve[i].kve_start == base) { 385 rtldpath = kve[i].kve_path; 386 break; 387 } 388 } 389 if (i == count) 390 goto err; 391 392 if (rtld_syms(rdap, rtldpath, base) != 0) 393 goto err; 394 395 rderr = RD_OK; 396 397 err: 398 if (kve != NULL) 399 procstat_freevmmap(rdap->rda_procstat, kve); 400 if (auxv != NULL) 401 procstat_freeauxv(rdap->rda_procstat, auxv); 402 if (kp != NULL) 403 procstat_freeprocs(rdap->rda_procstat, kp); 404 return (rderr); 405 } 406