1 /* 2 * Copyright (c) 2003, 2017, 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 <thread_db.h> 30 #include "libproc_impl.h" 31 32 #define SA_ALTROOT "SA_ALTROOT" 33 34 int pathmap_open(const char* name) { 35 static const char *alt_root = NULL; 36 static int alt_root_initialized = 0; 37 38 int fd; 39 char alt_path[PATH_MAX + 1], *alt_path_end; 40 const char *s; 41 int free_space; 42 43 if (!alt_root_initialized) { 44 alt_root_initialized = -1; 45 alt_root = getenv(SA_ALTROOT); 46 } 47 48 if (alt_root == NULL) { 49 return open(name, O_RDONLY); 50 } 51 52 53 if (strlen(alt_root) + strlen(name) > PATH_MAX) { 54 // Buffer too small. 55 return -1; 56 } 57 58 strncpy(alt_path, alt_root, PATH_MAX); 59 alt_path[PATH_MAX] = '\0'; 60 alt_path_end = alt_path + strlen(alt_path); 61 free_space = PATH_MAX + 1 - (alt_path_end-alt_path); 62 63 // Strip path items one by one and try to open file with alt_root prepended. 64 s = name; 65 while (1) { 66 strncat(alt_path, s, free_space); 67 s += 1; // Skip /. 68 69 fd = open(alt_path, O_RDONLY); 70 if (fd >= 0) { 71 print_debug("path %s substituted for %s\n", alt_path, name); 72 return fd; 73 } 74 75 // Linker always put full path to solib to process, so we can rely 76 // on presence of /. If slash is not present, it means, that SOlib doesn't 77 // physically exist (e.g. linux-gate.so) and we fail opening it anyway 78 if ((s = strchr(s, '/')) == NULL) { 79 break; 80 } 81 82 // Cut off what we appended above. 83 *alt_path_end = '\0'; 84 } 85 86 return -1; 87 } 88 89 static bool _libsaproc_debug; 90 91 void print_debug(const char* format,...) { 92 if (_libsaproc_debug) { 93 va_list alist; 94 95 va_start(alist, format); 96 fputs("libsaproc DEBUG: ", stderr); 97 vfprintf(stderr, format, alist); 98 va_end(alist); 99 } 100 } 101 102 void print_error(const char* format,...) { 103 va_list alist; 104 va_start(alist, format); 105 fputs("ERROR: ", stderr); 106 vfprintf(stderr, format, alist); 107 va_end(alist); 108 } 109 110 bool is_debug() { 111 return _libsaproc_debug; 112 } 113 114 // initialize libproc 115 bool init_libproc(bool debug) { 116 // init debug mode 117 _libsaproc_debug = debug; 118 119 // initialize the thread_db library 120 if (td_init() != TD_OK) { 121 print_debug("libthread_db's td_init failed\n"); 122 return false; 123 } 124 125 return true; 126 } 127 128 static void destroy_lib_info(struct ps_prochandle* ph) { 129 lib_info* lib = ph->libs; 130 while (lib) { 131 lib_info *next = lib->next; 132 if (lib->symtab) { 133 destroy_symtab(lib->symtab); 134 } 135 free(lib); 136 lib = next; 137 } 138 } 139 140 static void destroy_thread_info(struct ps_prochandle* ph) { 141 thread_info* thr = ph->threads; 142 while (thr) { 143 thread_info *next = thr->next; 144 free(thr); 145 thr = next; 146 } 147 } 148 149 // ps_prochandle cleanup 150 151 // ps_prochandle cleanup 152 void Prelease(struct ps_prochandle* ph) { 153 // do the "derived class" clean-up first 154 ph->ops->release(ph); 155 destroy_lib_info(ph); 156 destroy_thread_info(ph); 157 free(ph); 158 } 159 160 lib_info* add_lib_info(struct ps_prochandle* ph, const char* libname, uintptr_t base) { 161 return add_lib_info_fd(ph, libname, -1, base); 162 } 163 164 lib_info* add_lib_info_fd(struct ps_prochandle* ph, const char* libname, int fd, uintptr_t base) { 165 lib_info* newlib; 166 167 if ( (newlib = (lib_info*) calloc(1, sizeof(struct lib_info))) == NULL) { 168 print_debug("can't allocate memory for lib_info\n"); 169 return NULL; 170 } 171 172 if (strlen(libname) >= sizeof(newlib->name)) { 173 print_debug("libname %s too long\n", libname); 174 free(newlib); 175 return NULL; 176 } 177 strcpy(newlib->name, libname); 178 179 newlib->base = base; 180 181 if (fd == -1) { 182 if ( (newlib->fd = pathmap_open(newlib->name)) < 0) { 183 print_debug("can't open shared object %s\n", newlib->name); 184 free(newlib); 185 return NULL; 186 } 187 } else { 188 newlib->fd = fd; 189 } 190 191 // check whether we have got an ELF file. /proc/<pid>/map 192 // gives out all file mappings and not just shared objects 193 if (is_elf_file(newlib->fd) == false) { 194 close(newlib->fd); 195 free(newlib); 196 return NULL; 197 } 198 199 newlib->symtab = build_symtab(newlib->fd, libname); 200 if (newlib->symtab == NULL) { 201 print_debug("symbol table build failed for %s\n", newlib->name); 202 } 203 204 // even if symbol table building fails, we add the lib_info. 205 // This is because we may need to read from the ELF file for core file 206 // address read functionality. lookup_symbol checks for NULL symtab. 207 if (ph->libs) { 208 ph->lib_tail->next = newlib; 209 ph->lib_tail = newlib; 210 } else { 211 ph->libs = ph->lib_tail = newlib; 212 } 213 ph->num_libs++; 214 215 return newlib; 216 } 217 218 // lookup for a specific symbol 219 uintptr_t lookup_symbol(struct ps_prochandle* ph, const char* object_name, 220 const char* sym_name) { 221 // ignore object_name. search in all libraries 222 // FIXME: what should we do with object_name?? The library names are obtained 223 // by parsing /proc/<pid>/maps, which may not be the same as object_name. 224 // What we need is a utility to map object_name to real file name, something 225 // dlopen() does by looking at LD_LIBRARY_PATH and /etc/ld.so.cache. For 226 // now, we just ignore object_name and do a global search for the symbol. 227 228 lib_info* lib = ph->libs; 229 while (lib) { 230 if (lib->symtab) { 231 uintptr_t res = search_symbol(lib->symtab, lib->base, sym_name, NULL); 232 if (res) return res; 233 } 234 lib = lib->next; 235 } 236 237 print_debug("lookup failed for symbol '%s' in obj '%s'\n", 238 sym_name, object_name); 239 return (uintptr_t) NULL; 240 } 241 242 243 const char* symbol_for_pc(struct ps_prochandle* ph, uintptr_t addr, uintptr_t* poffset) { 244 const char* res = NULL; 245 lib_info* lib = ph->libs; 246 while (lib) { 247 if (lib->symtab && addr >= lib->base) { 248 res = nearest_symbol(lib->symtab, addr - lib->base, poffset); 249 if (res) return res; 250 } 251 lib = lib->next; 252 } 253 return NULL; 254 } 255 256 // add a thread to ps_prochandle 257 thread_info* add_thread_info(struct ps_prochandle* ph, pthread_t pthread_id, lwpid_t lwp_id) { 258 thread_info* newthr; 259 if ( (newthr = (thread_info*) calloc(1, sizeof(thread_info))) == NULL) { 260 print_debug("can't allocate memory for thread_info\n"); 261 return NULL; 262 } 263 264 // initialize thread info 265 newthr->pthread_id = pthread_id; 266 newthr->lwp_id = lwp_id; 267 268 // add new thread to the list 269 newthr->next = ph->threads; 270 ph->threads = newthr; 271 ph->num_threads++; 272 return newthr; 273 } 274 275 276 // struct used for client data from thread_db callback 277 struct thread_db_client_data { 278 struct ps_prochandle* ph; 279 thread_info_callback callback; 280 }; 281 282 // callback function for libthread_db 283 static int thread_db_callback(const td_thrhandle_t *th_p, void *data) { 284 struct thread_db_client_data* ptr = (struct thread_db_client_data*) data; 285 td_thrinfo_t ti; 286 td_err_e err; 287 288 memset(&ti, 0, sizeof(ti)); 289 err = td_thr_get_info(th_p, &ti); 290 if (err != TD_OK) { 291 print_debug("libthread_db : td_thr_get_info failed, can't get thread info\n"); 292 return err; 293 } 294 295 print_debug("thread_db : pthread %d (lwp %d)\n", ti.ti_tid, ti.ti_lid); 296 297 if (ptr->callback(ptr->ph, ti.ti_tid, ti.ti_lid) != true) 298 return TD_ERR; 299 300 return TD_OK; 301 } 302 303 // read thread_info using libthread_db 304 bool read_thread_info(struct ps_prochandle* ph, thread_info_callback cb) { 305 struct thread_db_client_data mydata; 306 td_thragent_t* thread_agent = NULL; 307 if (td_ta_new(ph, &thread_agent) != TD_OK) { 308 print_debug("can't create libthread_db agent\n"); 309 return false; 310 } 311 312 mydata.ph = ph; 313 mydata.callback = cb; 314 315 // we use libthread_db iterator to iterate thru list of threads. 316 if (td_ta_thr_iter(thread_agent, thread_db_callback, &mydata, 317 TD_THR_ANY_STATE, TD_THR_LOWEST_PRIORITY, 318 TD_SIGNO_MASK, TD_THR_ANY_USER_FLAGS) != TD_OK) { 319 td_ta_delete(thread_agent); 320 return false; 321 } 322 323 // delete thread agent 324 td_ta_delete(thread_agent); 325 return true; 326 } 327 328 329 // get number of threads 330 int get_num_threads(struct ps_prochandle* ph) { 331 return ph->num_threads; 332 } 333 334 // get lwp_id of n'th thread 335 lwpid_t get_lwp_id(struct ps_prochandle* ph, int index) { 336 int count = 0; 337 thread_info* thr = ph->threads; 338 while (thr) { 339 if (count == index) { 340 return thr->lwp_id; 341 } 342 count++; 343 thr = thr->next; 344 } 345 return -1; 346 } 347 348 // get regs for a given lwp 349 bool get_lwp_regs(struct ps_prochandle* ph, lwpid_t lwp_id, struct user_regs_struct* regs) { 350 return ph->ops->get_lwp_regs(ph, lwp_id, regs); 351 } 352 353 // get number of shared objects 354 int get_num_libs(struct ps_prochandle* ph) { 355 return ph->num_libs; 356 } 357 358 // get name of n'th solib 359 const char* get_lib_name(struct ps_prochandle* ph, int index) { 360 int count = 0; 361 lib_info* lib = ph->libs; 362 while (lib) { 363 if (count == index) { 364 return lib->name; 365 } 366 count++; 367 lib = lib->next; 368 } 369 return NULL; 370 } 371 372 // get base address of a lib 373 uintptr_t get_lib_base(struct ps_prochandle* ph, int index) { 374 int count = 0; 375 lib_info* lib = ph->libs; 376 while (lib) { 377 if (count == index) { 378 return lib->base; 379 } 380 count++; 381 lib = lib->next; 382 } 383 return (uintptr_t)NULL; 384 } 385 386 bool find_lib(struct ps_prochandle* ph, const char *lib_name) { 387 lib_info *p = ph->libs; 388 while (p) { 389 if (strcmp(p->name, lib_name) == 0) { 390 return true; 391 } 392 p = p->next; 393 } 394 return false; 395 } 396 397 //-------------------------------------------------------------------------- 398 // proc service functions 399 400 // get process id 401 pid_t ps_getpid(struct ps_prochandle *ph) { 402 return ph->pid; 403 } 404 405 // ps_pglobal_lookup() looks up the symbol sym_name in the symbol table 406 // of the load object object_name in the target process identified by ph. 407 // It returns the symbol's value as an address in the target process in 408 // *sym_addr. 409 410 ps_err_e ps_pglobal_lookup(struct ps_prochandle *ph, const char *object_name, 411 const char *sym_name, psaddr_t *sym_addr) { 412 *sym_addr = (psaddr_t) lookup_symbol(ph, object_name, sym_name); 413 return (*sym_addr ? PS_OK : PS_NOSYM); 414 } 415 416 // read "size" bytes info "buf" from address "addr" 417 ps_err_e ps_pdread(struct ps_prochandle *ph, psaddr_t addr, 418 void *buf, size_t size) { 419 return ph->ops->p_pread(ph, (uintptr_t) addr, buf, size)? PS_OK: PS_ERR; 420 } 421 422 // write "size" bytes of data to debuggee at address "addr" 423 ps_err_e ps_pdwrite(struct ps_prochandle *ph, psaddr_t addr, 424 const void *buf, size_t size) { 425 return ph->ops->p_pwrite(ph, (uintptr_t)addr, buf, size)? PS_OK: PS_ERR; 426 } 427 428 // ------------------------------------------------------------------------ 429 // Functions below this point are not yet implemented. They are here only 430 // to make the linker happy. 431 432 ps_err_e ps_lsetfpregs(struct ps_prochandle *ph, lwpid_t lid, const prfpregset_t *fpregs) { 433 print_debug("ps_lsetfpregs not implemented\n"); 434 return PS_OK; 435 } 436 437 ps_err_e ps_lsetregs(struct ps_prochandle *ph, lwpid_t lid, const prgregset_t gregset) { 438 print_debug("ps_lsetregs not implemented\n"); 439 return PS_OK; 440 } 441 442 ps_err_e ps_lgetfpregs(struct ps_prochandle *ph, lwpid_t lid, prfpregset_t *fpregs) { 443 print_debug("ps_lgetfpregs not implemented\n"); 444 return PS_OK; 445 } 446 447 ps_err_e ps_lgetregs(struct ps_prochandle *ph, lwpid_t lid, prgregset_t gregset) { 448 print_debug("ps_lgetfpregs not implemented\n"); 449 return PS_OK; 450 } 451 452 // new libthread_db of NPTL seem to require this symbol 453 ps_err_e ps_get_thread_area() { 454 print_debug("ps_get_thread_area not implemented\n"); 455 return PS_OK; 456 }