1 /* 2 * Copyright (c) 2010 The FreeBSD Foundation 3 * All rights reserved. 4 * 5 * This software was developed by Rui Paulo under sponsorship from the 6 * FreeBSD Foundation. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 #include <sys/cdefs.h> 31 __FBSDID("$FreeBSD$"); 32 33 #include <sys/param.h> 34 #include <sys/queue.h> 35 #include <sys/sysctl.h> 36 #include <sys/user.h> 37 38 #include <assert.h> 39 #include <err.h> 40 #include <fcntl.h> 41 #include <limits.h> 42 #include <stdio.h> 43 #include <stdlib.h> 44 #include <string.h> 45 #include <unistd.h> 46 47 #include <machine/elf.h> 48 49 #include <libelf.h> 50 #include <libproc.h> 51 #include <libprocstat.h> 52 #include <libutil.h> 53 54 #include "rtld_db.h" 55 56 static int _librtld_db_debug = 0; 57 #define DPRINTF(...) do { \ 58 if (_librtld_db_debug) { \ 59 fprintf(stderr, "librtld_db: DEBUG: "); \ 60 fprintf(stderr, __VA_ARGS__); \ 61 } \ 62 } while (0) 63 64 void 65 rd_delete(rd_agent_t *rdap) 66 { 67 68 if (rdap->rda_procstat != NULL) 69 procstat_close(rdap->rda_procstat); 70 free(rdap); 71 } 72 73 const char * 74 rd_errstr(rd_err_e rderr) 75 { 76 77 switch (rderr) { 78 case RD_ERR: 79 return "generic error"; 80 case RD_OK: 81 return "no error"; 82 case RD_NOCAPAB: 83 return "capability not supported"; 84 case RD_DBERR: 85 return "database error"; 86 case RD_NOBASE: 87 return "NOBASE"; 88 case RD_NOMAPS: 89 return "NOMAPS"; 90 default: 91 return "unknown error"; 92 } 93 } 94 95 rd_err_e 96 rd_event_addr(rd_agent_t *rdap, rd_event_e event, rd_notify_t *notify) 97 { 98 rd_err_e ret; 99 100 DPRINTF("%s rdap %p event %d notify %p\n", __func__, rdap, event, 101 notify); 102 103 ret = RD_OK; 104 switch (event) { 105 case RD_NONE: 106 break; 107 case RD_PREINIT: 108 notify->type = RD_NOTIFY_BPT; 109 notify->u.bptaddr = rdap->rda_preinit_addr; 110 break; 111 case RD_POSTINIT: 112 notify->type = RD_NOTIFY_BPT; 113 notify->u.bptaddr = rdap->rda_postinit_addr; 114 break; 115 case RD_DLACTIVITY: 116 notify->type = RD_NOTIFY_BPT; 117 notify->u.bptaddr = rdap->rda_dlactivity_addr; 118 break; 119 default: 120 ret = RD_ERR; 121 break; 122 } 123 return (ret); 124 } 125 126 rd_err_e 127 rd_event_enable(rd_agent_t *rdap __unused, int onoff) 128 { 129 DPRINTF("%s onoff %d\n", __func__, onoff); 130 131 return (RD_OK); 132 } 133 134 rd_err_e 135 rd_event_getmsg(rd_agent_t *rdap __unused, rd_event_msg_t *msg) 136 { 137 DPRINTF("%s\n", __func__); 138 139 msg->type = RD_POSTINIT; 140 msg->u.state = RD_CONSISTENT; 141 142 return (RD_OK); 143 } 144 145 rd_err_e 146 rd_init(int version) 147 { 148 char *debug = NULL; 149 150 if (version == RD_VERSION) { 151 debug = getenv("LIBRTLD_DB_DEBUG"); 152 _librtld_db_debug = debug ? atoi(debug) : 0; 153 return (RD_OK); 154 } else 155 return (RD_NOCAPAB); 156 } 157 158 rd_err_e 159 rd_loadobj_iter(rd_agent_t *rdap, rl_iter_f *cb, void *clnt_data) 160 { 161 struct kinfo_vmentry *kves, *kve; 162 rd_loadobj_t rdl; 163 rd_err_e ret; 164 int cnt, i, lastvn; 165 166 DPRINTF("%s\n", __func__); 167 168 if ((kves = kinfo_getvmmap(proc_getpid(rdap->rda_php), &cnt)) == NULL) { 169 warn("ERROR: kinfo_getvmmap() failed"); 170 return (RD_ERR); 171 } 172 173 ret = RD_OK; 174 lastvn = 0; 175 for (i = 0; i < cnt; i++) { 176 kve = kves + i; 177 if (kve->kve_type == KVME_TYPE_VNODE) 178 lastvn = i; 179 memset(&rdl, 0, sizeof(rdl)); 180 /* 181 * Map the kinfo_vmentry struct to the rd_loadobj structure. 182 */ 183 rdl.rdl_saddr = kve->kve_start; 184 rdl.rdl_eaddr = kve->kve_end; 185 rdl.rdl_offset = kve->kve_offset; 186 if (kve->kve_protection & KVME_PROT_READ) 187 rdl.rdl_prot |= RD_RDL_R; 188 if (kve->kve_protection & KVME_PROT_WRITE) 189 rdl.rdl_prot |= RD_RDL_W; 190 if (kve->kve_protection & KVME_PROT_EXEC) 191 rdl.rdl_prot |= RD_RDL_X; 192 strlcpy(rdl.rdl_path, kves[lastvn].kve_path, 193 sizeof(rdl.rdl_path)); 194 if ((*cb)(&rdl, clnt_data) != 0) { 195 ret = RD_ERR; 196 break; 197 } 198 } 199 free(kves); 200 return (ret); 201 } 202 203 void 204 rd_log(const int onoff) 205 { 206 DPRINTF("%s\n", __func__); 207 208 (void)onoff; 209 } 210 211 rd_agent_t * 212 rd_new(struct proc_handle *php) 213 { 214 rd_agent_t *rdap; 215 216 rdap = malloc(sizeof(*rdap)); 217 if (rdap == NULL) 218 return (NULL); 219 220 memset(rdap, 0, sizeof(rd_agent_t)); 221 rdap->rda_php = php; 222 rdap->rda_procstat = procstat_open_sysctl(); 223 224 if (rd_reset(rdap) != RD_OK) { 225 rd_delete(rdap); 226 rdap = NULL; 227 } 228 return (rdap); 229 } 230 231 rd_err_e 232 rd_objpad_enable(rd_agent_t *rdap, size_t padsize) 233 { 234 DPRINTF("%s\n", __func__); 235 236 (void)rdap; 237 (void)padsize; 238 239 return (RD_ERR); 240 } 241 242 rd_err_e 243 rd_plt_resolution(rd_agent_t *rdap, uintptr_t pc, struct proc *proc, 244 uintptr_t plt_base, rd_plt_info_t *rpi) 245 { 246 DPRINTF("%s\n", __func__); 247 248 (void)rdap; 249 (void)pc; 250 (void)proc; 251 (void)plt_base; 252 (void)rpi; 253 254 return (RD_ERR); 255 } 256 257 static int 258 rtld_syms(rd_agent_t *rdap, const char *rtldpath, u_long base) 259 { 260 GElf_Shdr shdr; 261 GElf_Sym sym; 262 Elf *e; 263 Elf_Data *data; 264 Elf_Scn *scn; 265 const char *symname; 266 Elf64_Word strscnidx; 267 int fd, i, ret; 268 269 ret = 1; 270 e = NULL; 271 272 fd = open(rtldpath, O_RDONLY); 273 if (fd < 0) 274 goto err; 275 276 if (elf_version(EV_CURRENT) == EV_NONE) 277 goto err; 278 e = elf_begin(fd, ELF_C_READ, NULL); 279 if (e == NULL) { 280 close(fd); 281 goto err; 282 } 283 284 scn = NULL; 285 while ((scn = elf_nextscn(e, scn)) != NULL) { 286 gelf_getshdr(scn, &shdr); 287 if (shdr.sh_type == SHT_DYNSYM) 288 break; 289 } 290 if (scn == NULL) 291 goto err; 292 293 strscnidx = shdr.sh_link; 294 data = elf_getdata(scn, NULL); 295 if (data == NULL) 296 goto err; 297 298 for (i = 0; gelf_getsym(data, i, &sym) != NULL; i++) { 299 if (GELF_ST_TYPE(sym.st_info) != STT_FUNC || 300 GELF_ST_BIND(sym.st_info) != STB_GLOBAL) 301 continue; 302 symname = elf_strptr(e, strscnidx, sym.st_name); 303 if (symname == NULL) 304 continue; 305 306 if (strcmp(symname, "r_debug_state") == 0) { 307 rdap->rda_preinit_addr = sym.st_value + base; 308 rdap->rda_dlactivity_addr = sym.st_value + base; 309 } else if (strcmp(symname, "_r_debug_postinit") == 0) { 310 rdap->rda_postinit_addr = sym.st_value + base; 311 } 312 } 313 314 if (rdap->rda_preinit_addr != 0 && 315 rdap->rda_postinit_addr != 0 && 316 rdap->rda_dlactivity_addr != 0) 317 ret = 0; 318 319 err: 320 if (e != NULL) 321 (void)elf_end(e); 322 if (fd >= 0) 323 (void)close(fd); 324 return (ret); 325 } 326 327 rd_err_e 328 rd_reset(rd_agent_t *rdap) 329 { 330 struct kinfo_proc *kp; 331 struct kinfo_vmentry *kve; 332 Elf_Auxinfo *auxv; 333 const char *rtldpath; 334 u_long base; 335 rd_err_e rderr; 336 int count, i; 337 338 kp = NULL; 339 auxv = NULL; 340 kve = NULL; 341 rderr = RD_ERR; 342 343 kp = procstat_getprocs(rdap->rda_procstat, KERN_PROC_PID, 344 proc_getpid(rdap->rda_php), &count); 345 if (kp == NULL) 346 return (RD_ERR); 347 assert(count == 1); 348 349 auxv = procstat_getauxv(rdap->rda_procstat, kp, &count); 350 if (auxv == NULL) 351 goto err; 352 353 base = 0; 354 for (i = 0; i < count; i++) { 355 if (auxv[i].a_type == AT_BASE) { 356 base = auxv[i].a_un.a_val; 357 break; 358 } 359 } 360 if (i == count) 361 goto err; 362 363 rtldpath = NULL; 364 kve = procstat_getvmmap(rdap->rda_procstat, kp, &count); 365 if (kve == NULL) 366 goto err; 367 for (i = 0; i < count; i++) { 368 if (kve[i].kve_start == base) { 369 rtldpath = kve[i].kve_path; 370 break; 371 } 372 } 373 if (i == count) 374 goto err; 375 376 if (rtld_syms(rdap, rtldpath, base) != 0) 377 goto err; 378 379 rderr = RD_OK; 380 381 err: 382 if (kve != NULL) 383 procstat_freevmmap(rdap->rda_procstat, kve); 384 if (auxv != NULL) 385 procstat_freeauxv(rdap->rda_procstat, auxv); 386 if (kp != NULL) 387 procstat_freeprocs(rdap->rda_procstat, kp); 388 return (rderr); 389 } 390