1 /* 2 * Copyright (c) 2003, 2013, 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 42 if (!alt_root_initialized) { 43 alt_root_initialized = -1; 44 alt_root = getenv(SA_ALTROOT); 45 } 46 47 if (alt_root == NULL) { 48 return open(name, O_RDONLY); 49 } 50 51 strcpy(alt_path, alt_root); 52 alt_path_end = alt_path + strlen(alt_path); 53 54 // Strip path items one by one and try to open file with alt_root prepended 55 s = name; 56 while (1) { 57 strcat(alt_path, s); 58 s += 1; 59 60 fd = open(alt_path, O_RDONLY); 61 if (fd >= 0) { 62 print_debug("path %s substituted for %s\n", alt_path, name); 63 return fd; 64 } 65 66 // Linker always put full path to solib to process, so we can rely 67 // on presence of /. If slash is not present, it means, that SOlib doesn't 68 // physically exist (e.g. linux-gate.so) and we fail opening it anyway 69 if ((s = strchr(s, '/')) == NULL) { 70 break; 71 } 72 73 *alt_path_end = 0; 74 } 75 76 return -1; 77 } 78 79 static bool _libsaproc_debug; 80 81 void print_debug(const char* format,...) { 82 if (_libsaproc_debug) { 83 va_list alist; 84 85 va_start(alist, format); 86 fputs("libsaproc DEBUG: ", stderr); 87 vfprintf(stderr, format, alist); 88 va_end(alist); 89 } 90 } 91 92 void print_error(const char* format,...) { 93 va_list alist; 94 va_start(alist, format); 95 fputs("ERROR: ", stderr); 96 vfprintf(stderr, format, alist); 97 va_end(alist); 98 } 99 100 bool is_debug() { 101 return _libsaproc_debug; 102 } 103 104 // initialize libproc 105 bool init_libproc(bool debug) { 106 // init debug mode 107 _libsaproc_debug = debug; 108 109 // initialize the thread_db library 110 if (td_init() != TD_OK) { 111 print_debug("libthread_db's td_init failed\n"); 112 return false; 113 } 114 115 return true; 116 } 117 118 static void destroy_lib_info(struct ps_prochandle* ph) { 119 lib_info* lib = ph->libs; 120 while (lib) { 121 lib_info *next = lib->next; 122 if (lib->symtab) { 123 destroy_symtab(lib->symtab); 124 } 125 free(lib); 126 lib = next; 127 } 128 } 129 130 static void destroy_thread_info(struct ps_prochandle* ph) { 131 thread_info* thr = ph->threads; 132 while (thr) { 133 thread_info *next = thr->next; 134 free(thr); 135 thr = next; 136 } 137 } 138 139 // ps_prochandle cleanup 140 141 // ps_prochandle cleanup 142 void Prelease(struct ps_prochandle* ph) { 143 // do the "derived class" clean-up first 144 ph->ops->release(ph); 145 destroy_lib_info(ph); 146 destroy_thread_info(ph); 147 free(ph); 148 } 149 150 lib_info* add_lib_info(struct ps_prochandle* ph, const char* libname, uintptr_t base) { 151 return add_lib_info_fd(ph, libname, -1, base); 152 } 153 154 lib_info* add_lib_info_fd(struct ps_prochandle* ph, const char* libname, int fd, uintptr_t base) { 155 lib_info* newlib; 156 157 if ( (newlib = (lib_info*) calloc(1, sizeof(struct lib_info))) == NULL) { 158 print_debug("can't allocate memory for lib_info\n"); 159 return NULL; 160 } 161 162 strncpy(newlib->name, libname, sizeof(newlib->name)); 163 newlib->base = base; 164 165 if (fd == -1) { 166 if ( (newlib->fd = pathmap_open(newlib->name)) < 0) { 167 print_debug("can't open shared object %s\n", newlib->name); 168 free(newlib); 169 return NULL; 170 } 171 } else { 172 newlib->fd = fd; 173 } 174 175 // check whether we have got an ELF file. /proc/<pid>/map 176 // gives out all file mappings and not just shared objects 177 if (is_elf_file(newlib->fd) == false) { 178 close(newlib->fd); 179 free(newlib); 180 return NULL; 181 } 182 183 newlib->symtab = build_symtab(newlib->fd, libname); 184 if (newlib->symtab == NULL) { 185 print_debug("symbol table build failed for %s\n", newlib->name); 186 } 187 188 // even if symbol table building fails, we add the lib_info. 189 // This is because we may need to read from the ELF file for core file 190 // address read functionality. lookup_symbol checks for NULL symtab. 191 if (ph->libs) { 192 ph->lib_tail->next = newlib; 193 ph->lib_tail = newlib; 194 } else { 195 ph->libs = ph->lib_tail = newlib; 196 } 197 ph->num_libs++; 198 199 return newlib; 200 } 201 202 // lookup for a specific symbol 203 uintptr_t lookup_symbol(struct ps_prochandle* ph, const char* object_name, 204 const char* sym_name) { 205 // ignore object_name. search in all libraries 206 // FIXME: what should we do with object_name?? The library names are obtained 207 // by parsing /proc/<pid>/maps, which may not be the same as object_name. 208 // What we need is a utility to map object_name to real file name, something 209 // dlopen() does by looking at LD_LIBRARY_PATH and /etc/ld.so.cache. For 210 // now, we just ignore object_name and do a global search for the symbol. 211 212 lib_info* lib = ph->libs; 213 while (lib) { 214 if (lib->symtab) { 215 uintptr_t res = search_symbol(lib->symtab, lib->base, sym_name, NULL); 216 if (res) return res; 217 } 218 lib = lib->next; 219 } 220 221 print_debug("lookup failed for symbol '%s' in obj '%s'\n", 222 sym_name, object_name); 223 return (uintptr_t) NULL; 224 } 225 226 227 const char* symbol_for_pc(struct ps_prochandle* ph, uintptr_t addr, uintptr_t* poffset) { 228 const char* res = NULL; 229 lib_info* lib = ph->libs; 230 while (lib) { 231 if (lib->symtab && addr >= lib->base) { 232 res = nearest_symbol(lib->symtab, addr - lib->base, poffset); 233 if (res) return res; 234 } 235 lib = lib->next; 236 } 237 return NULL; 238 } 239 240 // add a thread to ps_prochandle 241 thread_info* add_thread_info(struct ps_prochandle* ph, pthread_t pthread_id, lwpid_t lwp_id) { 242 thread_info* newthr; 243 if ( (newthr = (thread_info*) calloc(1, sizeof(thread_info))) == NULL) { 244 print_debug("can't allocate memory for thread_info\n"); 245 return NULL; 246 } 247 248 // initialize thread info 249 newthr->pthread_id = pthread_id; 250 newthr->lwp_id = lwp_id; 251 252 // add new thread to the list 253 newthr->next = ph->threads; 254 ph->threads = newthr; 255 ph->num_threads++; 256 return newthr; 257 } 258 259 260 // struct used for client data from thread_db callback 261 struct thread_db_client_data { 262 struct ps_prochandle* ph; 263 thread_info_callback callback; 264 }; 265 266 // callback function for libthread_db 267 static int thread_db_callback(const td_thrhandle_t *th_p, void *data) { 268 struct thread_db_client_data* ptr = (struct thread_db_client_data*) data; 269 td_thrinfo_t ti; 270 td_err_e err; 271 272 memset(&ti, 0, sizeof(ti)); 273 err = td_thr_get_info(th_p, &ti); 274 if (err != TD_OK) { 275 print_debug("libthread_db : td_thr_get_info failed, can't get thread info\n"); 276 return err; 277 } 278 279 print_debug("thread_db : pthread %d (lwp %d)\n", ti.ti_tid, ti.ti_lid); 280 281 if (ptr->callback(ptr->ph, ti.ti_tid, ti.ti_lid) != true) 282 return TD_ERR; 283 284 return TD_OK; 285 } 286 287 // read thread_info using libthread_db 288 bool read_thread_info(struct ps_prochandle* ph, thread_info_callback cb) { 289 struct thread_db_client_data mydata; 290 td_thragent_t* thread_agent = NULL; 291 if (td_ta_new(ph, &thread_agent) != TD_OK) { 292 print_debug("can't create libthread_db agent\n"); 293 return false; 294 } 295 296 mydata.ph = ph; 297 mydata.callback = cb; 298 299 // we use libthread_db iterator to iterate thru list of threads. 300 if (td_ta_thr_iter(thread_agent, thread_db_callback, &mydata, 301 TD_THR_ANY_STATE, TD_THR_LOWEST_PRIORITY, 302 TD_SIGNO_MASK, TD_THR_ANY_USER_FLAGS) != TD_OK) { 303 td_ta_delete(thread_agent); 304 return false; 305 } 306 307 // delete thread agent 308 td_ta_delete(thread_agent); 309 return true; 310 } 311 312 313 // get number of threads 314 int get_num_threads(struct ps_prochandle* ph) { 315 return ph->num_threads; 316 } 317 318 // get lwp_id of n'th thread 319 lwpid_t get_lwp_id(struct ps_prochandle* ph, int index) { 320 int count = 0; 321 thread_info* thr = ph->threads; 322 while (thr) { 323 if (count == index) { 324 return thr->lwp_id; 325 } 326 count++; 327 thr = thr->next; 328 } 329 return -1; 330 } 331 332 // get regs for a given lwp 333 bool get_lwp_regs(struct ps_prochandle* ph, lwpid_t lwp_id, struct user_regs_struct* regs) { 334 return ph->ops->get_lwp_regs(ph, lwp_id, regs); 335 } 336 337 // get number of shared objects 338 int get_num_libs(struct ps_prochandle* ph) { 339 return ph->num_libs; 340 } 341 342 // get name of n'th solib 343 const char* get_lib_name(struct ps_prochandle* ph, int index) { 344 int count = 0; 345 lib_info* lib = ph->libs; 346 while (lib) { 347 if (count == index) { 348 return lib->name; 349 } 350 count++; 351 lib = lib->next; 352 } 353 return NULL; 354 } 355 356 // get base address of a lib 357 uintptr_t get_lib_base(struct ps_prochandle* ph, int index) { 358 int count = 0; 359 lib_info* lib = ph->libs; 360 while (lib) { 361 if (count == index) { 362 return lib->base; 363 } 364 count++; 365 lib = lib->next; 366 } 367 return (uintptr_t)NULL; 368 } 369 370 bool find_lib(struct ps_prochandle* ph, const char *lib_name) { 371 lib_info *p = ph->libs; 372 while (p) { 373 if (strcmp(p->name, lib_name) == 0) { 374 return true; 375 } 376 p = p->next; 377 } 378 return false; 379 } 380 381 //-------------------------------------------------------------------------- 382 // proc service functions 383 384 // get process id 385 pid_t ps_getpid(struct ps_prochandle *ph) { 386 return ph->pid; 387 } 388 389 // ps_pglobal_lookup() looks up the symbol sym_name in the symbol table 390 // of the load object object_name in the target process identified by ph. 391 // It returns the symbol's value as an address in the target process in 392 // *sym_addr. 393 394 ps_err_e ps_pglobal_lookup(struct ps_prochandle *ph, const char *object_name, 395 const char *sym_name, psaddr_t *sym_addr) { 396 *sym_addr = (psaddr_t) lookup_symbol(ph, object_name, sym_name); 397 return (*sym_addr ? PS_OK : PS_NOSYM); 398 } 399 400 // read "size" bytes info "buf" from address "addr" 401 ps_err_e ps_pdread(struct ps_prochandle *ph, psaddr_t addr, 402 void *buf, size_t size) { 403 return ph->ops->p_pread(ph, (uintptr_t) addr, buf, size)? PS_OK: PS_ERR; 404 } 405 406 // write "size" bytes of data to debuggee at address "addr" 407 ps_err_e ps_pdwrite(struct ps_prochandle *ph, psaddr_t addr, 408 const void *buf, size_t size) { 409 return ph->ops->p_pwrite(ph, (uintptr_t)addr, buf, size)? PS_OK: PS_ERR; 410 } 411 412 // ------------------------------------------------------------------------ 413 // Functions below this point are not yet implemented. They are here only 414 // to make the linker happy. 415 416 ps_err_e ps_lsetfpregs(struct ps_prochandle *ph, lwpid_t lid, const prfpregset_t *fpregs) { 417 print_debug("ps_lsetfpregs not implemented\n"); 418 return PS_OK; 419 } 420 421 ps_err_e ps_lsetregs(struct ps_prochandle *ph, lwpid_t lid, const prgregset_t gregset) { 422 print_debug("ps_lsetregs not implemented\n"); 423 return PS_OK; 424 } 425 426 ps_err_e ps_lgetfpregs(struct ps_prochandle *ph, lwpid_t lid, prfpregset_t *fpregs) { 427 print_debug("ps_lgetfpregs not implemented\n"); 428 return PS_OK; 429 } 430 431 ps_err_e ps_lgetregs(struct ps_prochandle *ph, lwpid_t lid, prgregset_t gregset) { 432 print_debug("ps_lgetfpregs not implemented\n"); 433 return PS_OK; 434 } 435 436 // new libthread_db of NPTL seem to require this symbol 437 ps_err_e ps_get_thread_area() { 438 print_debug("ps_get_thread_area not implemented\n"); 439 return PS_OK; 440 }