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 rd_loadobj_t rdl; 164 rd_err_e ret; 165 int cnt, i, lastvn; 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 ret = RD_OK; 175 lastvn = 0; 176 for (i = 0; i < cnt; i++) { 177 kve = kves + i; 178 if (kve->kve_type == KVME_TYPE_VNODE) 179 lastvn = i; 180 memset(&rdl, 0, sizeof(rdl)); 181 /* 182 * Map the kinfo_vmentry struct to the rd_loadobj structure. 183 */ 184 rdl.rdl_saddr = kve->kve_start; 185 rdl.rdl_eaddr = kve->kve_end; 186 rdl.rdl_offset = kve->kve_offset; 187 if (kve->kve_protection & KVME_PROT_READ) 188 rdl.rdl_prot |= RD_RDL_R; 189 if (kve->kve_protection & KVME_PROT_WRITE) 190 rdl.rdl_prot |= RD_RDL_W; 191 if (kve->kve_protection & KVME_PROT_EXEC) 192 rdl.rdl_prot |= RD_RDL_X; 193 strlcpy(rdl.rdl_path, kves[lastvn].kve_path, 194 sizeof(rdl.rdl_path)); 195 if ((*cb)(&rdl, clnt_data) != 0) { 196 ret = RD_ERR; 197 break; 198 } 199 } 200 free(kves); 201 return (ret); 202 } 203 204 void 205 rd_log(const int onoff) 206 { 207 DPRINTF("%s\n", __func__); 208 209 (void)onoff; 210 } 211 212 rd_agent_t * 213 rd_new(struct proc_handle *php) 214 { 215 rd_agent_t *rdap; 216 217 rdap = malloc(sizeof(*rdap)); 218 if (rdap == NULL) 219 return (NULL); 220 221 memset(rdap, 0, sizeof(rd_agent_t)); 222 rdap->rda_php = php; 223 rdap->rda_procstat = procstat_open_sysctl(); 224 225 if (rd_reset(rdap) != RD_OK) { 226 rd_delete(rdap); 227 rdap = NULL; 228 } 229 return (rdap); 230 } 231 232 rd_err_e 233 rd_objpad_enable(rd_agent_t *rdap, size_t padsize) 234 { 235 DPRINTF("%s\n", __func__); 236 237 (void)rdap; 238 (void)padsize; 239 240 return (RD_ERR); 241 } 242 243 rd_err_e 244 rd_plt_resolution(rd_agent_t *rdap, uintptr_t pc, struct proc *proc, 245 uintptr_t plt_base, rd_plt_info_t *rpi) 246 { 247 DPRINTF("%s\n", __func__); 248 249 (void)rdap; 250 (void)pc; 251 (void)proc; 252 (void)plt_base; 253 (void)rpi; 254 255 return (RD_ERR); 256 } 257 258 static int 259 rtld_syms(rd_agent_t *rdap, const char *rtldpath, u_long base) 260 { 261 GElf_Shdr shdr; 262 GElf_Sym sym; 263 Elf *e; 264 Elf_Data *data; 265 Elf_Scn *scn; 266 const char *symname; 267 Elf64_Word strscnidx; 268 int fd, i, ret; 269 270 ret = 1; 271 e = NULL; 272 273 fd = open(rtldpath, O_RDONLY); 274 if (fd < 0) 275 goto err; 276 277 if (elf_version(EV_CURRENT) == EV_NONE) 278 goto err; 279 e = elf_begin(fd, ELF_C_READ, NULL); 280 if (e == NULL) 281 goto err; 282 283 scn = NULL; 284 while ((scn = elf_nextscn(e, scn)) != NULL) { 285 gelf_getshdr(scn, &shdr); 286 if (shdr.sh_type == SHT_DYNSYM) 287 break; 288 } 289 if (scn == NULL) 290 goto err; 291 292 strscnidx = shdr.sh_link; 293 data = elf_getdata(scn, NULL); 294 if (data == NULL) 295 goto err; 296 297 for (i = 0; gelf_getsym(data, i, &sym) != NULL; i++) { 298 if (GELF_ST_TYPE(sym.st_info) != STT_FUNC || 299 GELF_ST_BIND(sym.st_info) != STB_GLOBAL) 300 continue; 301 symname = elf_strptr(e, strscnidx, sym.st_name); 302 if (symname == NULL) 303 continue; 304 305 if (strcmp(symname, "r_debug_state") == 0) { 306 rdap->rda_preinit_addr = sym.st_value + base; 307 rdap->rda_dlactivity_addr = sym.st_value + base; 308 } else if (strcmp(symname, "_r_debug_postinit") == 0) { 309 rdap->rda_postinit_addr = sym.st_value + base; 310 } 311 } 312 313 if (rdap->rda_preinit_addr != 0 && 314 rdap->rda_postinit_addr != 0 && 315 rdap->rda_dlactivity_addr != 0) 316 ret = 0; 317 318 err: 319 if (e != NULL) 320 (void)elf_end(e); 321 if (fd >= 0) 322 (void)close(fd); 323 return (ret); 324 } 325 326 rd_err_e 327 rd_reset(rd_agent_t *rdap) 328 { 329 struct kinfo_proc *kp; 330 struct kinfo_vmentry *kve; 331 Elf_Auxinfo *auxv; 332 const char *rtldpath; 333 u_long base; 334 rd_err_e rderr; 335 int count, i; 336 337 kp = NULL; 338 auxv = NULL; 339 kve = NULL; 340 rderr = RD_ERR; 341 342 kp = procstat_getprocs(rdap->rda_procstat, KERN_PROC_PID, 343 proc_getpid(rdap->rda_php), &count); 344 if (kp == NULL) 345 return (RD_ERR); 346 assert(count == 1); 347 348 auxv = procstat_getauxv(rdap->rda_procstat, kp, &count); 349 if (auxv == NULL) 350 goto err; 351 352 base = 0; 353 for (i = 0; i < count; i++) { 354 if (auxv[i].a_type == AT_BASE) { 355 base = auxv[i].a_un.a_val; 356 break; 357 } 358 } 359 if (i == count) 360 goto err; 361 362 rtldpath = NULL; 363 kve = procstat_getvmmap(rdap->rda_procstat, kp, &count); 364 if (kve == NULL) 365 goto err; 366 for (i = 0; i < count; i++) { 367 if (kve[i].kve_start == base) { 368 rtldpath = kve[i].kve_path; 369 break; 370 } 371 } 372 if (i == count) 373 goto err; 374 375 if (rtld_syms(rdap, rtldpath, base) != 0) 376 goto err; 377 378 rderr = RD_OK; 379 380 err: 381 if (kve != NULL) 382 procstat_freevmmap(rdap->rda_procstat, kve); 383 if (auxv != NULL) 384 procstat_freeauxv(rdap->rda_procstat, auxv); 385 if (kp != NULL) 386 procstat_freeprocs(rdap->rda_procstat, kp); 387 return (rderr); 388 } 389