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/sysctl.h> 35 #include <sys/user.h> 36 37 #include <assert.h> 38 #include <err.h> 39 #include <fcntl.h> 40 #include <limits.h> 41 #include <stdio.h> 42 #include <stdlib.h> 43 #include <string.h> 44 #include <unistd.h> 45 46 #include <machine/elf.h> 47 48 #include <libelf.h> 49 #include <libproc.h> 50 #include <libprocstat.h> 51 #include <libutil.h> 52 53 #include "rtld_db.h" 54 55 static int _librtld_db_debug = 0; 56 #define DPRINTF(...) do { \ 57 if (_librtld_db_debug) { \ 58 fprintf(stderr, "librtld_db: DEBUG: "); \ 59 fprintf(stderr, __VA_ARGS__); \ 60 } \ 61 } while (0) 62 63 void 64 rd_delete(rd_agent_t *rdap) 65 { 66 67 if (rdap->rda_procstat != NULL) 68 procstat_close(rdap->rda_procstat); 69 free(rdap); 70 } 71 72 const char * 73 rd_errstr(rd_err_e rderr) 74 { 75 76 switch (rderr) { 77 case RD_ERR: 78 return "generic error"; 79 case RD_OK: 80 return "no error"; 81 case RD_NOCAPAB: 82 return "capability not supported"; 83 case RD_DBERR: 84 return "database error"; 85 case RD_NOBASE: 86 return "NOBASE"; 87 case RD_NOMAPS: 88 return "NOMAPS"; 89 default: 90 return "unknown error"; 91 } 92 } 93 94 rd_err_e 95 rd_event_addr(rd_agent_t *rdap, rd_event_e event, rd_notify_t *notify) 96 { 97 rd_err_e ret; 98 99 DPRINTF("%s rdap %p event %d notify %p\n", __func__, rdap, event, 100 notify); 101 102 ret = RD_OK; 103 switch (event) { 104 case RD_NONE: 105 break; 106 case RD_PREINIT: 107 notify->type = RD_NOTIFY_BPT; 108 notify->u.bptaddr = rdap->rda_preinit_addr; 109 break; 110 case RD_POSTINIT: 111 notify->type = RD_NOTIFY_BPT; 112 notify->u.bptaddr = rdap->rda_postinit_addr; 113 break; 114 case RD_DLACTIVITY: 115 notify->type = RD_NOTIFY_BPT; 116 notify->u.bptaddr = rdap->rda_dlactivity_addr; 117 break; 118 default: 119 ret = RD_ERR; 120 break; 121 } 122 return (ret); 123 } 124 125 rd_err_e 126 rd_event_enable(rd_agent_t *rdap __unused, int onoff) 127 { 128 DPRINTF("%s onoff %d\n", __func__, onoff); 129 130 return (RD_OK); 131 } 132 133 rd_err_e 134 rd_event_getmsg(rd_agent_t *rdap __unused, rd_event_msg_t *msg) 135 { 136 DPRINTF("%s\n", __func__); 137 138 msg->type = RD_POSTINIT; 139 msg->u.state = RD_CONSISTENT; 140 141 return (RD_OK); 142 } 143 144 rd_err_e 145 rd_init(int version) 146 { 147 char *debug = NULL; 148 149 if (version == RD_VERSION) { 150 debug = getenv("LIBRTLD_DB_DEBUG"); 151 _librtld_db_debug = debug ? atoi(debug) : 0; 152 return (RD_OK); 153 } else 154 return (RD_NOCAPAB); 155 } 156 157 rd_err_e 158 rd_loadobj_iter(rd_agent_t *rdap, rl_iter_f *cb, void *clnt_data) 159 { 160 struct kinfo_vmentry *kves, *kve; 161 rd_loadobj_t rdl; 162 rd_err_e ret; 163 int cnt, i, lastvn; 164 165 DPRINTF("%s\n", __func__); 166 167 if ((kves = kinfo_getvmmap(proc_getpid(rdap->rda_php), &cnt)) == NULL) { 168 warn("ERROR: kinfo_getvmmap() failed"); 169 return (RD_ERR); 170 } 171 172 ret = RD_OK; 173 lastvn = 0; 174 for (i = 0; i < cnt; i++) { 175 kve = kves + i; 176 if (kve->kve_type == KVME_TYPE_VNODE) 177 lastvn = i; 178 memset(&rdl, 0, sizeof(rdl)); 179 /* 180 * Map the kinfo_vmentry struct to the rd_loadobj structure. 181 */ 182 rdl.rdl_saddr = kve->kve_start; 183 rdl.rdl_eaddr = kve->kve_end; 184 rdl.rdl_offset = kve->kve_offset; 185 if (kve->kve_protection & KVME_PROT_READ) 186 rdl.rdl_prot |= RD_RDL_R; 187 if (kve->kve_protection & KVME_PROT_WRITE) 188 rdl.rdl_prot |= RD_RDL_W; 189 if (kve->kve_protection & KVME_PROT_EXEC) 190 rdl.rdl_prot |= RD_RDL_X; 191 strlcpy(rdl.rdl_path, kves[lastvn].kve_path, 192 sizeof(rdl.rdl_path)); 193 if ((*cb)(&rdl, clnt_data) != 0) { 194 ret = RD_ERR; 195 break; 196 } 197 } 198 free(kves); 199 return (ret); 200 } 201 202 void 203 rd_log(const int onoff) 204 { 205 DPRINTF("%s\n", __func__); 206 207 (void)onoff; 208 } 209 210 rd_agent_t * 211 rd_new(struct proc_handle *php) 212 { 213 rd_agent_t *rdap; 214 215 rdap = malloc(sizeof(*rdap)); 216 if (rdap == NULL) 217 return (NULL); 218 219 memset(rdap, 0, sizeof(rd_agent_t)); 220 rdap->rda_php = php; 221 rdap->rda_procstat = procstat_open_sysctl(); 222 223 if (rd_reset(rdap) != RD_OK) { 224 rd_delete(rdap); 225 rdap = NULL; 226 } 227 return (rdap); 228 } 229 230 rd_err_e 231 rd_objpad_enable(rd_agent_t *rdap, size_t padsize) 232 { 233 DPRINTF("%s\n", __func__); 234 235 (void)rdap; 236 (void)padsize; 237 238 return (RD_ERR); 239 } 240 241 rd_err_e 242 rd_plt_resolution(rd_agent_t *rdap, uintptr_t pc, struct proc *proc, 243 uintptr_t plt_base, rd_plt_info_t *rpi) 244 { 245 DPRINTF("%s\n", __func__); 246 247 (void)rdap; 248 (void)pc; 249 (void)proc; 250 (void)plt_base; 251 (void)rpi; 252 253 return (RD_ERR); 254 } 255 256 static int 257 rtld_syms(rd_agent_t *rdap, const char *rtldpath, u_long base) 258 { 259 GElf_Shdr shdr; 260 GElf_Sym sym; 261 Elf *e; 262 Elf_Data *data; 263 Elf_Scn *scn; 264 const char *symname; 265 Elf64_Word strscnidx; 266 int fd, i, ret; 267 268 ret = 1; 269 e = NULL; 270 271 fd = open(rtldpath, O_RDONLY); 272 if (fd < 0) 273 goto err; 274 275 if (elf_version(EV_CURRENT) == EV_NONE) 276 goto err; 277 e = elf_begin(fd, ELF_C_READ, NULL); 278 if (e == NULL) 279 goto err; 280 281 scn = NULL; 282 while ((scn = elf_nextscn(e, scn)) != NULL) { 283 gelf_getshdr(scn, &shdr); 284 if (shdr.sh_type == SHT_DYNSYM) 285 break; 286 } 287 if (scn == NULL) 288 goto err; 289 290 strscnidx = shdr.sh_link; 291 data = elf_getdata(scn, NULL); 292 if (data == NULL) 293 goto err; 294 295 for (i = 0; gelf_getsym(data, i, &sym) != NULL; i++) { 296 if (GELF_ST_TYPE(sym.st_info) != STT_FUNC || 297 GELF_ST_BIND(sym.st_info) != STB_GLOBAL) 298 continue; 299 symname = elf_strptr(e, strscnidx, sym.st_name); 300 if (symname == NULL) 301 continue; 302 303 if (strcmp(symname, "r_debug_state") == 0) { 304 rdap->rda_preinit_addr = sym.st_value + base; 305 rdap->rda_dlactivity_addr = sym.st_value + base; 306 } else if (strcmp(symname, "_r_debug_postinit") == 0) { 307 rdap->rda_postinit_addr = sym.st_value + base; 308 } 309 } 310 311 if (rdap->rda_preinit_addr != 0 && 312 rdap->rda_postinit_addr != 0 && 313 rdap->rda_dlactivity_addr != 0) 314 ret = 0; 315 316 err: 317 if (e != NULL) 318 (void)elf_end(e); 319 if (fd >= 0) 320 (void)close(fd); 321 return (ret); 322 } 323 324 rd_err_e 325 rd_reset(rd_agent_t *rdap) 326 { 327 struct kinfo_proc *kp; 328 struct kinfo_vmentry *kve; 329 Elf_Auxinfo *auxv; 330 const char *rtldpath; 331 u_long base; 332 rd_err_e rderr; 333 int count, i; 334 335 kp = NULL; 336 auxv = NULL; 337 kve = NULL; 338 rderr = RD_ERR; 339 340 kp = procstat_getprocs(rdap->rda_procstat, KERN_PROC_PID, 341 proc_getpid(rdap->rda_php), &count); 342 if (kp == NULL) 343 return (RD_ERR); 344 assert(count == 1); 345 346 auxv = procstat_getauxv(rdap->rda_procstat, kp, &count); 347 if (auxv == NULL) 348 goto err; 349 350 base = 0; 351 for (i = 0; i < count; i++) { 352 if (auxv[i].a_type == AT_BASE) { 353 base = auxv[i].a_un.a_val; 354 break; 355 } 356 } 357 if (i == count) 358 goto err; 359 360 rtldpath = NULL; 361 kve = procstat_getvmmap(rdap->rda_procstat, kp, &count); 362 if (kve == NULL) 363 goto err; 364 for (i = 0; i < count; i++) { 365 if (kve[i].kve_start == base) { 366 rtldpath = kve[i].kve_path; 367 break; 368 } 369 } 370 if (i == count) 371 goto err; 372 373 if (rtld_syms(rdap, rtldpath, base) != 0) 374 goto err; 375 376 rderr = RD_OK; 377 378 err: 379 if (kve != NULL) 380 procstat_freevmmap(rdap->rda_procstat, kve); 381 if (auxv != NULL) 382 procstat_freeauxv(rdap->rda_procstat, auxv); 383 if (kp != NULL) 384 procstat_freeprocs(rdap->rda_procstat, kp); 385 return (rderr); 386 } 387