1 /* 2 * Copyright (c) 2003, 2020, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 #include <stdarg.h> 25 #include <stdio.h> 26 #include <stdlib.h> 27 #include <string.h> 28 #include <fcntl.h> 29 #include <sys/procfs.h> 30 #include "libproc_impl.h" 31 #include "proc_service.h" 32 #include "salibelf.h" 33 34 #define SA_ALTROOT "SA_ALTROOT" 35 36 int pathmap_open(const char* name) { 37 static const char *alt_root = NULL; 38 static int alt_root_initialized = 0; 39 40 int fd; 41 char alt_path[PATH_MAX + 1], *alt_path_end; 42 const char *s; 43 int free_space; 44 45 if (!alt_root_initialized) { 46 alt_root_initialized = -1; 47 alt_root = getenv(SA_ALTROOT); 48 } 49 50 if (alt_root == NULL) { 51 return open(name, O_RDONLY); 52 } 53 54 55 if (strlen(alt_root) + strlen(name) > PATH_MAX) { 56 // Buffer too small. 57 return -1; 58 } 59 60 strncpy(alt_path, alt_root, PATH_MAX); 61 alt_path[PATH_MAX] = '\0'; 62 alt_path_end = alt_path + strlen(alt_path); 63 free_space = PATH_MAX + 1 - (alt_path_end-alt_path); 64 65 // Strip path items one by one and try to open file with alt_root prepended. 66 s = name; 67 while (1) { 68 strncat(alt_path, s, free_space); 69 s += 1; // Skip /. 70 71 fd = open(alt_path, O_RDONLY); 72 if (fd >= 0) { 73 print_debug("path %s substituted for %s\n", alt_path, name); 74 return fd; 75 } 76 77 // Linker always put full path to solib to process, so we can rely 78 // on presence of /. If slash is not present, it means, that SOlib doesn't 79 // physically exist (e.g. linux-gate.so) and we fail opening it anyway 80 if ((s = strchr(s, '/')) == NULL) { 81 break; 82 } 83 84 // Cut off what we appended above. 85 *alt_path_end = '\0'; 86 } 87 88 return -1; 89 } 90 91 static bool _libsaproc_debug; 92 93 void print_debug(const char* format,...) { 94 if (_libsaproc_debug) { 95 va_list alist; 96 97 va_start(alist, format); 98 fputs("libsaproc DEBUG: ", stderr); 99 vfprintf(stderr, format, alist); 100 va_end(alist); 101 } 102 } 103 104 void print_error(const char* format,...) { 105 va_list alist; 106 va_start(alist, format); 107 fputs("ERROR: ", stderr); 108 vfprintf(stderr, format, alist); 109 va_end(alist); 110 } 111 112 bool is_debug() { 113 return _libsaproc_debug; 114 } 115 116 // initialize libproc 117 JNIEXPORT bool JNICALL 118 init_libproc(bool debug) { 119 // init debug mode 120 _libsaproc_debug = debug; 121 return true; 122 } 123 124 static void destroy_lib_info(struct ps_prochandle* ph) { 125 lib_info* lib = ph->libs; 126 while (lib) { 127 lib_info *next = lib->next; 128 if (lib->symtab) { 129 destroy_symtab(lib->symtab); 130 } 131 free(lib->eh_frame.data); 132 free(lib); 133 lib = next; 134 } 135 } 136 137 static void destroy_thread_info(struct ps_prochandle* ph) { 138 thread_info* thr = ph->threads; 139 while (thr) { 140 thread_info *next = thr->next; 141 free(thr); 142 thr = next; 143 } 144 } 145 146 // ps_prochandle cleanup 147 148 // ps_prochandle cleanup 149 JNIEXPORT void JNICALL 150 Prelease(struct ps_prochandle* ph) { 151 // do the "derived class" clean-up first 152 ph->ops->release(ph); 153 destroy_lib_info(ph); 154 destroy_thread_info(ph); 155 free(ph); 156 } 157 158 lib_info* add_lib_info(struct ps_prochandle* ph, const char* libname, uintptr_t base) { 159 return add_lib_info_fd(ph, libname, -1, base); 160 } 161 162 static bool fill_instr_info(lib_info* lib) { 163 off_t current_pos; 164 ELF_EHDR ehdr; 165 ELF_PHDR* phbuf = NULL; 166 ELF_PHDR* ph = NULL; 167 int cnt; 168 long align = sysconf(_SC_PAGE_SIZE); 169 170 current_pos = lseek(lib->fd, (off_t)0L, SEEK_CUR); 171 lseek(lib->fd, (off_t)0L, SEEK_SET); 172 read_elf_header(lib->fd, &ehdr); 173 if ((phbuf = read_program_header_table(lib->fd, &ehdr)) == NULL) { 174 lseek(lib->fd, current_pos, SEEK_SET); 175 return false; 176 } 177 178 lib->exec_start = (uintptr_t)-1L; 179 lib->exec_end = (uintptr_t)-1L; 180 for (ph = phbuf, cnt = 0; cnt < ehdr.e_phnum; cnt++, ph++) { 181 if ((ph->p_type == PT_LOAD) && (ph->p_flags & PF_X)) { 182 print_debug("[%d] vaddr = 0x%lx, memsz = 0x%lx, filesz = 0x%lx\n", cnt, ph->p_vaddr, ph->p_memsz, ph->p_filesz); 183 if ((lib->exec_start == -1L) || (lib->exec_start > ph->p_vaddr)) { 184 lib->exec_start = ph->p_vaddr; 185 } 186 if ((lib->exec_end == (uintptr_t)-1L) || (lib->exec_end < (ph->p_vaddr + ph->p_memsz))) { 187 lib->exec_end = ph->p_vaddr + ph->p_memsz; 188 } 189 align = ph->p_align; 190 } 191 } 192 193 free(phbuf); 194 lseek(lib->fd, current_pos, SEEK_SET); 195 196 if ((lib->exec_start == -1L) || (lib->exec_end == -1L)) { 197 return false; 198 } else { 199 lib->exec_start = (lib->exec_start + lib->base) & ~(align - 1); 200 lib->exec_end = (lib->exec_end + lib->base + align) & ~(align - 1); 201 return true; 202 } 203 204 } 205 206 bool read_eh_frame(struct ps_prochandle* ph, lib_info* lib) { 207 off_t current_pos = -1; 208 ELF_EHDR ehdr; 209 ELF_SHDR* shbuf = NULL; 210 ELF_SHDR* sh = NULL; 211 char* strtab = NULL; 212 void* result = NULL; 213 int cnt; 214 215 current_pos = lseek(lib->fd, (off_t)0L, SEEK_CUR); 216 lseek(lib->fd, (off_t)0L, SEEK_SET); 217 218 read_elf_header(lib->fd, &ehdr); 219 shbuf = read_section_header_table(lib->fd, &ehdr); 220 strtab = read_section_data(lib->fd, &ehdr, &shbuf[ehdr.e_shstrndx]); 221 222 for (cnt = 0, sh = shbuf; cnt < ehdr.e_shnum; cnt++, sh++) { 223 if (strcmp(".eh_frame", sh->sh_name + strtab) == 0) { 224 lib->eh_frame.library_base_addr = lib->base; 225 lib->eh_frame.v_addr = sh->sh_addr; 226 lib->eh_frame.data = read_section_data(lib->fd, &ehdr, sh); 227 lib->eh_frame.size = sh->sh_size; 228 break; 229 } 230 } 231 232 free(strtab); 233 free(shbuf); 234 lseek(lib->fd, current_pos, SEEK_SET); 235 return lib->eh_frame.data != NULL; 236 } 237 238 lib_info* add_lib_info_fd(struct ps_prochandle* ph, const char* libname, int fd, uintptr_t base) { 239 lib_info* newlib; 240 241 if ( (newlib = (lib_info*) calloc(1, sizeof(struct lib_info))) == NULL) { 242 print_debug("can't allocate memory for lib_info\n"); 243 return NULL; 244 } 245 246 if (strlen(libname) >= sizeof(newlib->name)) { 247 print_debug("libname %s too long\n", libname); 248 free(newlib); 249 return NULL; 250 } 251 strcpy(newlib->name, libname); 252 253 newlib->base = base; 254 255 if (fd == -1) { 256 if ( (newlib->fd = pathmap_open(newlib->name)) < 0) { 257 print_debug("can't open shared object %s\n", newlib->name); 258 free(newlib); 259 return NULL; 260 } 261 } else { 262 newlib->fd = fd; 263 } 264 265 // check whether we have got an ELF file. /proc/<pid>/map 266 // gives out all file mappings and not just shared objects 267 if (is_elf_file(newlib->fd) == false) { 268 close(newlib->fd); 269 free(newlib); 270 return NULL; 271 } 272 273 newlib->symtab = build_symtab(newlib->fd, libname); 274 if (newlib->symtab == NULL) { 275 print_debug("symbol table build failed for %s\n", newlib->name); 276 } 277 278 if (fill_instr_info(newlib)) { 279 if (!read_eh_frame(ph, newlib)) { 280 print_debug("Could not find .eh_frame section in %s\n", newlib->name); 281 } 282 } else { 283 print_debug("Could not find executable section in %s\n", newlib->name); 284 } 285 286 // even if symbol table building fails, we add the lib_info. 287 // This is because we may need to read from the ELF file for core file 288 // address read functionality. lookup_symbol checks for NULL symtab. 289 if (ph->libs) { 290 ph->lib_tail->next = newlib; 291 ph->lib_tail = newlib; 292 } else { 293 ph->libs = ph->lib_tail = newlib; 294 } 295 ph->num_libs++; 296 297 return newlib; 298 } 299 300 // lookup for a specific symbol 301 uintptr_t lookup_symbol(struct ps_prochandle* ph, const char* object_name, 302 const char* sym_name) { 303 // ignore object_name. search in all libraries 304 // FIXME: what should we do with object_name?? The library names are obtained 305 // by parsing /proc/<pid>/maps, which may not be the same as object_name. 306 // What we need is a utility to map object_name to real file name, something 307 // dlopen() does by looking at LD_LIBRARY_PATH and /etc/ld.so.cache. For 308 // now, we just ignore object_name and do a global search for the symbol. 309 310 lib_info* lib = ph->libs; 311 while (lib) { 312 if (lib->symtab) { 313 uintptr_t res = search_symbol(lib->symtab, lib->base, sym_name, NULL); 314 if (res) return res; 315 } 316 lib = lib->next; 317 } 318 319 print_debug("lookup failed for symbol '%s' in obj '%s'\n", 320 sym_name, object_name); 321 return (uintptr_t) NULL; 322 } 323 324 325 const char* symbol_for_pc(struct ps_prochandle* ph, uintptr_t addr, uintptr_t* poffset) { 326 const char* res = NULL; 327 lib_info* lib = ph->libs; 328 while (lib) { 329 if (lib->symtab && addr >= lib->base) { 330 res = nearest_symbol(lib->symtab, addr - lib->base, poffset); 331 if (res) return res; 332 } 333 lib = lib->next; 334 } 335 return NULL; 336 } 337 338 // add a thread to ps_prochandle 339 thread_info* add_thread_info(struct ps_prochandle* ph, lwpid_t lwp_id) { 340 thread_info* newthr; 341 if ( (newthr = (thread_info*) calloc(1, sizeof(thread_info))) == NULL) { 342 print_debug("can't allocate memory for thread_info\n"); 343 return NULL; 344 } 345 346 // initialize thread info 347 newthr->lwp_id = lwp_id; 348 349 // add new thread to the list 350 newthr->next = ph->threads; 351 ph->threads = newthr; 352 ph->num_threads++; 353 return newthr; 354 } 355 356 void delete_thread_info(struct ps_prochandle* ph, thread_info* thr_to_be_removed) { 357 thread_info* current_thr = ph->threads; 358 359 if (thr_to_be_removed == ph->threads) { 360 ph->threads = ph->threads->next; 361 } else { 362 thread_info* previous_thr = NULL; 363 while (current_thr && current_thr != thr_to_be_removed) { 364 previous_thr = current_thr; 365 current_thr = current_thr->next; 366 } 367 if (current_thr == NULL) { 368 print_error("Could not find the thread to be removed"); 369 return; 370 } 371 previous_thr->next = current_thr->next; 372 } 373 ph->num_threads--; 374 free(current_thr); 375 } 376 377 // get number of threads 378 int get_num_threads(struct ps_prochandle* ph) { 379 return ph->num_threads; 380 } 381 382 // get lwp_id of n'th thread 383 lwpid_t get_lwp_id(struct ps_prochandle* ph, int index) { 384 int count = 0; 385 thread_info* thr = ph->threads; 386 while (thr) { 387 if (count == index) { 388 return thr->lwp_id; 389 } 390 count++; 391 thr = thr->next; 392 } 393 return -1; 394 } 395 396 // get regs for a given lwp 397 bool get_lwp_regs(struct ps_prochandle* ph, lwpid_t lwp_id, struct user_regs_struct* regs) { 398 return ph->ops->get_lwp_regs(ph, lwp_id, regs); 399 } 400 401 // get number of shared objects 402 int get_num_libs(struct ps_prochandle* ph) { 403 return ph->num_libs; 404 } 405 406 // get name of n'th solib 407 const char* get_lib_name(struct ps_prochandle* ph, int index) { 408 int count = 0; 409 lib_info* lib = ph->libs; 410 while (lib) { 411 if (count == index) { 412 return lib->name; 413 } 414 count++; 415 lib = lib->next; 416 } 417 return NULL; 418 } 419 420 // get base address of a lib 421 uintptr_t get_lib_base(struct ps_prochandle* ph, int index) { 422 int count = 0; 423 lib_info* lib = ph->libs; 424 while (lib) { 425 if (count == index) { 426 return lib->base; 427 } 428 count++; 429 lib = lib->next; 430 } 431 return (uintptr_t)NULL; 432 } 433 434 bool find_lib(struct ps_prochandle* ph, const char *lib_name) { 435 lib_info *p = ph->libs; 436 while (p) { 437 if (strcmp(p->name, lib_name) == 0) { 438 return true; 439 } 440 p = p->next; 441 } 442 return false; 443 } 444 445 struct lib_info *find_lib_by_address(struct ps_prochandle* ph, uintptr_t pc) { 446 lib_info *p = ph->libs; 447 while (p) { 448 if ((p->exec_start <= pc) && (pc < p->exec_end)) { 449 return p; 450 } 451 p = p->next; 452 } 453 return NULL; 454 } 455 456 //-------------------------------------------------------------------------- 457 // proc service functions 458 459 // get process id 460 JNIEXPORT pid_t JNICALL 461 ps_getpid(struct ps_prochandle *ph) { 462 return ph->pid; 463 } 464 465 // ps_pglobal_lookup() looks up the symbol sym_name in the symbol table 466 // of the load object object_name in the target process identified by ph. 467 // It returns the symbol's value as an address in the target process in 468 // *sym_addr. 469 470 JNIEXPORT ps_err_e JNICALL 471 ps_pglobal_lookup(struct ps_prochandle *ph, const char *object_name, 472 const char *sym_name, psaddr_t *sym_addr) { 473 *sym_addr = (psaddr_t) lookup_symbol(ph, object_name, sym_name); 474 return (*sym_addr ? PS_OK : PS_NOSYM); 475 } 476 477 // read "size" bytes info "buf" from address "addr" 478 JNIEXPORT ps_err_e JNICALL 479 ps_pdread(struct ps_prochandle *ph, psaddr_t addr, 480 void *buf, size_t size) { 481 return ph->ops->p_pread(ph, (uintptr_t) addr, buf, size)? PS_OK: PS_ERR; 482 } 483 484 // write "size" bytes of data to debuggee at address "addr" 485 JNIEXPORT ps_err_e JNICALL 486 ps_pdwrite(struct ps_prochandle *ph, psaddr_t addr, 487 const void *buf, size_t size) { 488 return ph->ops->p_pwrite(ph, (uintptr_t)addr, buf, size)? PS_OK: PS_ERR; 489 } 490 491 // ------------------------------------------------------------------------ 492 // Functions below this point are not yet implemented. They are here only 493 // to make the linker happy. 494 495 JNIEXPORT ps_err_e JNICALL 496 ps_lsetfpregs(struct ps_prochandle *ph, lwpid_t lid, const prfpregset_t *fpregs) { 497 print_debug("ps_lsetfpregs not implemented\n"); 498 return PS_OK; 499 } 500 501 JNIEXPORT ps_err_e JNICALL 502 ps_lsetregs(struct ps_prochandle *ph, lwpid_t lid, const prgregset_t gregset) { 503 print_debug("ps_lsetregs not implemented\n"); 504 return PS_OK; 505 } 506 507 JNIEXPORT ps_err_e JNICALL 508 ps_lgetfpregs(struct ps_prochandle *ph, lwpid_t lid, prfpregset_t *fpregs) { 509 print_debug("ps_lgetfpregs not implemented\n"); 510 return PS_OK; 511 } 512 513 JNIEXPORT ps_err_e JNICALL 514 ps_lgetregs(struct ps_prochandle *ph, lwpid_t lid, prgregset_t gregset) { 515 print_debug("ps_lgetfpregs not implemented\n"); 516 return PS_OK; 517 } 518