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 = 0L; 179 lib->exec_end = 0L; 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 == 0L) || (lib->exec_start > ph->p_vaddr)) { 184 lib->exec_start = ph->p_vaddr; 185 } 186 if (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 == 0L) || (lib->exec_end == 0L)) { 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 break; 228 } 229 } 230 231 free(strtab); 232 free(shbuf); 233 lseek(lib->fd, current_pos, SEEK_SET); 234 return lib->eh_frame.data != NULL; 235 } 236 237 lib_info* add_lib_info_fd(struct ps_prochandle* ph, const char* libname, int fd, uintptr_t base) { 238 lib_info* newlib; 239 240 if ( (newlib = (lib_info*) calloc(1, sizeof(struct lib_info))) == NULL) { 241 print_debug("can't allocate memory for lib_info\n"); 242 return NULL; 243 } 244 245 if (strlen(libname) >= sizeof(newlib->name)) { 246 print_debug("libname %s too long\n", libname); 247 free(newlib); 248 return NULL; 249 } 250 strcpy(newlib->name, libname); 251 252 newlib->base = base; 253 254 if (fd == -1) { 255 if ( (newlib->fd = pathmap_open(newlib->name)) < 0) { 256 print_debug("can't open shared object %s\n", newlib->name); 257 free(newlib); 258 return NULL; 259 } 260 } else { 261 newlib->fd = fd; 262 } 263 264 // check whether we have got an ELF file. /proc/<pid>/map 265 // gives out all file mappings and not just shared objects 266 if (is_elf_file(newlib->fd) == false) { 267 close(newlib->fd); 268 free(newlib); 269 return NULL; 270 } 271 272 newlib->symtab = build_symtab(newlib->fd, libname); 273 if (newlib->symtab == NULL) { 274 print_debug("symbol table build failed for %s\n", newlib->name); 275 } 276 277 if (fill_instr_info(newlib)) { 278 if (!read_eh_frame(ph, newlib)) { 279 print_debug("Could not find .eh_frame section in %s\n", newlib->name); 280 } 281 } else { 282 print_debug("Could not find executable section in %s\n", newlib->name); 283 } 284 285 // even if symbol table building fails, we add the lib_info. 286 // This is because we may need to read from the ELF file for core file 287 // address read functionality. lookup_symbol checks for NULL symtab. 288 if (ph->libs) { 289 ph->lib_tail->next = newlib; 290 ph->lib_tail = newlib; 291 } else { 292 ph->libs = ph->lib_tail = newlib; 293 } 294 ph->num_libs++; 295 296 return newlib; 297 } 298 299 // lookup for a specific symbol 300 uintptr_t lookup_symbol(struct ps_prochandle* ph, const char* object_name, 301 const char* sym_name) { 302 // ignore object_name. search in all libraries 303 // FIXME: what should we do with object_name?? The library names are obtained 304 // by parsing /proc/<pid>/maps, which may not be the same as object_name. 305 // What we need is a utility to map object_name to real file name, something 306 // dlopen() does by looking at LD_LIBRARY_PATH and /etc/ld.so.cache. For 307 // now, we just ignore object_name and do a global search for the symbol. 308 309 lib_info* lib = ph->libs; 310 while (lib) { 311 if (lib->symtab) { 312 uintptr_t res = search_symbol(lib->symtab, lib->base, sym_name, NULL); 313 if (res) return res; 314 } 315 lib = lib->next; 316 } 317 318 print_debug("lookup failed for symbol '%s' in obj '%s'\n", 319 sym_name, object_name); 320 return (uintptr_t) NULL; 321 } 322 323 324 const char* symbol_for_pc(struct ps_prochandle* ph, uintptr_t addr, uintptr_t* poffset) { 325 const char* res = NULL; 326 lib_info* lib = ph->libs; 327 while (lib) { 328 if (lib->symtab && addr >= lib->base) { 329 res = nearest_symbol(lib->symtab, addr - lib->base, poffset); 330 if (res) return res; 331 } 332 lib = lib->next; 333 } 334 return NULL; 335 } 336 337 // add a thread to ps_prochandle 338 thread_info* add_thread_info(struct ps_prochandle* ph, lwpid_t lwp_id) { 339 thread_info* newthr; 340 if ( (newthr = (thread_info*) calloc(1, sizeof(thread_info))) == NULL) { 341 print_debug("can't allocate memory for thread_info\n"); 342 return NULL; 343 } 344 345 // initialize thread info 346 newthr->lwp_id = lwp_id; 347 348 // add new thread to the list 349 newthr->next = ph->threads; 350 ph->threads = newthr; 351 ph->num_threads++; 352 return newthr; 353 } 354 355 void delete_thread_info(struct ps_prochandle* ph, thread_info* thr_to_be_removed) { 356 thread_info* current_thr = ph->threads; 357 358 if (thr_to_be_removed == ph->threads) { 359 ph->threads = ph->threads->next; 360 } else { 361 thread_info* previous_thr = NULL; 362 while (current_thr && current_thr != thr_to_be_removed) { 363 previous_thr = current_thr; 364 current_thr = current_thr->next; 365 } 366 if (current_thr == NULL) { 367 print_error("Could not find the thread to be removed"); 368 return; 369 } 370 previous_thr->next = current_thr->next; 371 } 372 ph->num_threads--; 373 free(current_thr); 374 } 375 376 // get number of threads 377 int get_num_threads(struct ps_prochandle* ph) { 378 return ph->num_threads; 379 } 380 381 // get lwp_id of n'th thread 382 lwpid_t get_lwp_id(struct ps_prochandle* ph, int index) { 383 int count = 0; 384 thread_info* thr = ph->threads; 385 while (thr) { 386 if (count == index) { 387 return thr->lwp_id; 388 } 389 count++; 390 thr = thr->next; 391 } 392 return -1; 393 } 394 395 // get regs for a given lwp 396 bool get_lwp_regs(struct ps_prochandle* ph, lwpid_t lwp_id, struct user_regs_struct* regs) { 397 return ph->ops->get_lwp_regs(ph, lwp_id, regs); 398 } 399 400 // get number of shared objects 401 int get_num_libs(struct ps_prochandle* ph) { 402 return ph->num_libs; 403 } 404 405 // get name of n'th solib 406 const char* get_lib_name(struct ps_prochandle* ph, int index) { 407 int count = 0; 408 lib_info* lib = ph->libs; 409 while (lib) { 410 if (count == index) { 411 return lib->name; 412 } 413 count++; 414 lib = lib->next; 415 } 416 return NULL; 417 } 418 419 // get base address of a lib 420 uintptr_t get_lib_base(struct ps_prochandle* ph, int index) { 421 int count = 0; 422 lib_info* lib = ph->libs; 423 while (lib) { 424 if (count == index) { 425 return lib->base; 426 } 427 count++; 428 lib = lib->next; 429 } 430 return (uintptr_t)NULL; 431 } 432 433 bool find_lib(struct ps_prochandle* ph, const char *lib_name) { 434 lib_info *p = ph->libs; 435 while (p) { 436 if (strcmp(p->name, lib_name) == 0) { 437 return true; 438 } 439 p = p->next; 440 } 441 return false; 442 } 443 444 struct lib_info *find_lib_by_address(struct ps_prochandle* ph, uintptr_t pc) { 445 lib_info *p = ph->libs; 446 while (p) { 447 if ((p->exec_start <= pc) && (pc < p->exec_end)) { 448 return p; 449 } 450 p = p->next; 451 } 452 return NULL; 453 } 454 455 //-------------------------------------------------------------------------- 456 // proc service functions 457 458 // get process id 459 JNIEXPORT pid_t JNICALL 460 ps_getpid(struct ps_prochandle *ph) { 461 return ph->pid; 462 } 463 464 // ps_pglobal_lookup() looks up the symbol sym_name in the symbol table 465 // of the load object object_name in the target process identified by ph. 466 // It returns the symbol's value as an address in the target process in 467 // *sym_addr. 468 469 JNIEXPORT ps_err_e JNICALL 470 ps_pglobal_lookup(struct ps_prochandle *ph, const char *object_name, 471 const char *sym_name, psaddr_t *sym_addr) { 472 *sym_addr = (psaddr_t) lookup_symbol(ph, object_name, sym_name); 473 return (*sym_addr ? PS_OK : PS_NOSYM); 474 } 475 476 // read "size" bytes info "buf" from address "addr" 477 JNIEXPORT ps_err_e JNICALL 478 ps_pdread(struct ps_prochandle *ph, psaddr_t addr, 479 void *buf, size_t size) { 480 return ph->ops->p_pread(ph, (uintptr_t) addr, buf, size)? PS_OK: PS_ERR; 481 } 482 483 // write "size" bytes of data to debuggee at address "addr" 484 JNIEXPORT ps_err_e JNICALL 485 ps_pdwrite(struct ps_prochandle *ph, psaddr_t addr, 486 const void *buf, size_t size) { 487 return ph->ops->p_pwrite(ph, (uintptr_t)addr, buf, size)? PS_OK: PS_ERR; 488 } 489 490 // ------------------------------------------------------------------------ 491 // Functions below this point are not yet implemented. They are here only 492 // to make the linker happy. 493 494 JNIEXPORT ps_err_e JNICALL 495 ps_lsetfpregs(struct ps_prochandle *ph, lwpid_t lid, const prfpregset_t *fpregs) { 496 print_debug("ps_lsetfpregs not implemented\n"); 497 return PS_OK; 498 } 499 500 JNIEXPORT ps_err_e JNICALL 501 ps_lsetregs(struct ps_prochandle *ph, lwpid_t lid, const prgregset_t gregset) { 502 print_debug("ps_lsetregs not implemented\n"); 503 return PS_OK; 504 } 505 506 JNIEXPORT ps_err_e JNICALL 507 ps_lgetfpregs(struct ps_prochandle *ph, lwpid_t lid, prfpregset_t *fpregs) { 508 print_debug("ps_lgetfpregs not implemented\n"); 509 return PS_OK; 510 } 511 512 JNIEXPORT ps_err_e JNICALL 513 ps_lgetregs(struct ps_prochandle *ph, lwpid_t lid, prgregset_t gregset) { 514 print_debug("ps_lgetfpregs not implemented\n"); 515 return PS_OK; 516 } 517