1 /*
   2  * Copyright (c) 2003, 2019, 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 
  33 #define SA_ALTROOT "SA_ALTROOT"
  34 
  35 int pathmap_open(const char* name) {
  36   static const char *alt_root = NULL;
  37   static int alt_root_initialized = 0;
  38 
  39   int fd;
  40   char alt_path[PATH_MAX + 1], *alt_path_end;
  41   const char *s;
  42   int free_space;
  43 
  44   if (!alt_root_initialized) {
  45     alt_root_initialized = -1;
  46     alt_root = getenv(SA_ALTROOT);
  47   }
  48 
  49   if (alt_root == NULL) {
  50     return open(name, O_RDONLY);
  51   }
  52 
  53 
  54   if (strlen(alt_root) + strlen(name) > PATH_MAX) {
  55     // Buffer too small.
  56     return -1;
  57   }
  58 
  59   strncpy(alt_path, alt_root, PATH_MAX);
  60   alt_path[PATH_MAX] = '\0';
  61   alt_path_end = alt_path + strlen(alt_path);
  62   free_space = PATH_MAX + 1 - (alt_path_end-alt_path);
  63 
  64   // Strip path items one by one and try to open file with alt_root prepended.
  65   s = name;
  66   while (1) {
  67     strncat(alt_path, s, free_space);
  68     s += 1;  // Skip /.
  69 
  70     fd = open(alt_path, O_RDONLY);
  71     if (fd >= 0) {
  72       print_debug("path %s substituted for %s\n", alt_path, name);
  73       return fd;
  74     }
  75 
  76     // Linker always put full path to solib to process, so we can rely
  77     // on presence of /. If slash is not present, it means, that SOlib doesn't
  78     // physically exist (e.g. linux-gate.so) and we fail opening it anyway
  79     if ((s = strchr(s, '/')) == NULL) {
  80       break;
  81     }
  82 
  83     // Cut off what we appended above.
  84     *alt_path_end = '\0';
  85   }
  86 
  87   return -1;
  88 }
  89 
  90 static bool _libsaproc_debug;
  91 
  92 void print_debug(const char* format,...) {
  93    if (_libsaproc_debug) {
  94      va_list alist;
  95 
  96      va_start(alist, format);
  97      fputs("libsaproc DEBUG: ", stderr);
  98      vfprintf(stderr, format, alist);
  99      va_end(alist);
 100    }
 101 }
 102 
 103 void print_error(const char* format,...) {
 104   va_list alist;
 105   va_start(alist, format);
 106   fputs("ERROR: ", stderr);
 107   vfprintf(stderr, format, alist);
 108   va_end(alist);
 109 }
 110 
 111 bool is_debug() {
 112    return _libsaproc_debug;
 113 }
 114 
 115 // initialize libproc
 116 JNIEXPORT bool JNICALL
 117 init_libproc(bool debug) {
 118    // init debug mode
 119    _libsaproc_debug = debug;







 120    return true;
 121 }
 122 
 123 static void destroy_lib_info(struct ps_prochandle* ph) {
 124    lib_info* lib = ph->libs;
 125    while (lib) {
 126      lib_info *next = lib->next;
 127      if (lib->symtab) {
 128         destroy_symtab(lib->symtab);
 129      }
 130      free(lib);
 131      lib = next;
 132    }
 133 }
 134 
 135 static void destroy_thread_info(struct ps_prochandle* ph) {
 136    thread_info* thr = ph->threads;
 137    while (thr) {
 138      thread_info *next = thr->next;
 139      free(thr);
 140      thr = next;
 141    }
 142 }
 143 
 144 // ps_prochandle cleanup
 145 
 146 // ps_prochandle cleanup
 147 JNIEXPORT void JNICALL
 148 Prelease(struct ps_prochandle* ph) {
 149    // do the "derived class" clean-up first
 150    ph->ops->release(ph);
 151    destroy_lib_info(ph);
 152    destroy_thread_info(ph);
 153    free(ph);
 154 }
 155 
 156 lib_info* add_lib_info(struct ps_prochandle* ph, const char* libname, uintptr_t base) {
 157    return add_lib_info_fd(ph, libname, -1, base);
 158 }
 159 
 160 lib_info* add_lib_info_fd(struct ps_prochandle* ph, const char* libname, int fd, uintptr_t base) {
 161    lib_info* newlib;
 162 
 163    if ( (newlib = (lib_info*) calloc(1, sizeof(struct lib_info))) == NULL) {
 164       print_debug("can't allocate memory for lib_info\n");
 165       return NULL;
 166    }
 167 
 168    if (strlen(libname) >= sizeof(newlib->name)) {
 169      print_debug("libname %s too long\n", libname);
 170      free(newlib);
 171      return NULL;
 172    }
 173    strcpy(newlib->name, libname);
 174 
 175    newlib->base = base;
 176 
 177    if (fd == -1) {
 178       if ( (newlib->fd = pathmap_open(newlib->name)) < 0) {
 179          print_debug("can't open shared object %s\n", newlib->name);
 180          free(newlib);
 181          return NULL;
 182       }
 183    } else {
 184       newlib->fd = fd;
 185    }
 186 
 187    // check whether we have got an ELF file. /proc/<pid>/map
 188    // gives out all file mappings and not just shared objects
 189    if (is_elf_file(newlib->fd) == false) {
 190       close(newlib->fd);
 191       free(newlib);
 192       return NULL;
 193    }
 194 
 195    newlib->symtab = build_symtab(newlib->fd, libname);
 196    if (newlib->symtab == NULL) {
 197       print_debug("symbol table build failed for %s\n", newlib->name);
 198    }
 199 
 200    // even if symbol table building fails, we add the lib_info.
 201    // This is because we may need to read from the ELF file for core file
 202    // address read functionality. lookup_symbol checks for NULL symtab.
 203    if (ph->libs) {
 204       ph->lib_tail->next = newlib;
 205       ph->lib_tail = newlib;
 206    }  else {
 207       ph->libs = ph->lib_tail = newlib;
 208    }
 209    ph->num_libs++;
 210 
 211    return newlib;
 212 }
 213 
 214 // lookup for a specific symbol
 215 uintptr_t lookup_symbol(struct ps_prochandle* ph,  const char* object_name,
 216                        const char* sym_name) {
 217    // ignore object_name. search in all libraries
 218    // FIXME: what should we do with object_name?? The library names are obtained
 219    // by parsing /proc/<pid>/maps, which may not be the same as object_name.
 220    // What we need is a utility to map object_name to real file name, something
 221    // dlopen() does by looking at LD_LIBRARY_PATH and /etc/ld.so.cache. For
 222    // now, we just ignore object_name and do a global search for the symbol.
 223 
 224    lib_info* lib = ph->libs;
 225    while (lib) {
 226       if (lib->symtab) {
 227          uintptr_t res = search_symbol(lib->symtab, lib->base, sym_name, NULL);
 228          if (res) return res;
 229       }
 230       lib = lib->next;
 231    }
 232 
 233    print_debug("lookup failed for symbol '%s' in obj '%s'\n",
 234                           sym_name, object_name);
 235    return (uintptr_t) NULL;
 236 }
 237 
 238 
 239 const char* symbol_for_pc(struct ps_prochandle* ph, uintptr_t addr, uintptr_t* poffset) {
 240    const char* res = NULL;
 241    lib_info* lib = ph->libs;
 242    while (lib) {
 243       if (lib->symtab && addr >= lib->base) {
 244          res = nearest_symbol(lib->symtab, addr - lib->base, poffset);
 245          if (res) return res;
 246       }
 247       lib = lib->next;
 248    }
 249    return NULL;
 250 }
 251 
 252 // add a thread to ps_prochandle
 253 thread_info* add_thread_info(struct ps_prochandle* ph, lwpid_t lwp_id) {
 254    thread_info* newthr;
 255    if ( (newthr = (thread_info*) calloc(1, sizeof(thread_info))) == NULL) {
 256       print_debug("can't allocate memory for thread_info\n");
 257       return NULL;
 258    }
 259 
 260    // initialize thread info

 261    newthr->lwp_id = lwp_id;
 262 
 263    // add new thread to the list
 264    newthr->next = ph->threads;
 265    ph->threads = newthr;
 266    ph->num_threads++;
 267    return newthr;
 268 }
 269 
 270 void delete_thread_info(struct ps_prochandle* ph, thread_info* thr_to_be_removed) {
 271     thread_info* current_thr = ph->threads;
 272 
 273     if (thr_to_be_removed == ph->threads) {
 274       ph->threads = ph->threads->next;
 275     } else {
 276       thread_info* previous_thr;
 277       while (current_thr && current_thr != thr_to_be_removed) {
 278         previous_thr = current_thr;
 279         current_thr = current_thr->next;
 280       }
 281       if (current_thr == NULL) {
 282         print_error("Could not find the thread to be removed");
 283         return;
 284       }
 285       previous_thr->next = current_thr->next;
 286     }
 287     ph->num_threads--;
 288     free(current_thr);
 289 }
 290 


























































 291 // get number of threads
 292 int get_num_threads(struct ps_prochandle* ph) {
 293    return ph->num_threads;
 294 }
 295 
 296 // get lwp_id of n'th thread
 297 lwpid_t get_lwp_id(struct ps_prochandle* ph, int index) {
 298    int count = 0;
 299    thread_info* thr = ph->threads;
 300    while (thr) {
 301       if (count == index) {
 302          return thr->lwp_id;
 303       }
 304       count++;
 305       thr = thr->next;
 306    }
 307    return -1;
 308 }
 309 
 310 // get regs for a given lwp
 311 bool get_lwp_regs(struct ps_prochandle* ph, lwpid_t lwp_id, struct user_regs_struct* regs) {
 312   return ph->ops->get_lwp_regs(ph, lwp_id, regs);
 313 }
 314 
 315 // get number of shared objects
 316 int get_num_libs(struct ps_prochandle* ph) {
 317    return ph->num_libs;
 318 }
 319 
 320 // get name of n'th solib
 321 const char* get_lib_name(struct ps_prochandle* ph, int index) {
 322    int count = 0;
 323    lib_info* lib = ph->libs;
 324    while (lib) {
 325       if (count == index) {
 326          return lib->name;
 327       }
 328       count++;
 329       lib = lib->next;
 330    }
 331    return NULL;
 332 }
 333 
 334 // get base address of a lib
 335 uintptr_t get_lib_base(struct ps_prochandle* ph, int index) {
 336    int count = 0;
 337    lib_info* lib = ph->libs;
 338    while (lib) {
 339       if (count == index) {
 340          return lib->base;
 341       }
 342       count++;
 343       lib = lib->next;
 344    }
 345    return (uintptr_t)NULL;
 346 }
 347 
 348 bool find_lib(struct ps_prochandle* ph, const char *lib_name) {
 349   lib_info *p = ph->libs;
 350   while (p) {
 351     if (strcmp(p->name, lib_name) == 0) {
 352       return true;
 353     }
 354     p = p->next;
 355   }
 356   return false;
 357 }
 358 
 359 //--------------------------------------------------------------------------
 360 // proc service functions
 361 
 362 // get process id
 363 JNIEXPORT pid_t JNICALL
 364 ps_getpid(struct ps_prochandle *ph) {
 365    return ph->pid;
 366 }
 367 
 368 // ps_pglobal_lookup() looks up the symbol sym_name in the symbol table
 369 // of the load object object_name in the target process identified by ph.
 370 // It returns the symbol's value as an address in the target process in
 371 // *sym_addr.
 372 
 373 JNIEXPORT ps_err_e JNICALL
 374 ps_pglobal_lookup(struct ps_prochandle *ph, const char *object_name,
 375                     const char *sym_name, psaddr_t *sym_addr) {
 376   *sym_addr = (psaddr_t) lookup_symbol(ph, object_name, sym_name);
 377   return (*sym_addr ? PS_OK : PS_NOSYM);
 378 }
 379 
 380 // read "size" bytes info "buf" from address "addr"
 381 JNIEXPORT ps_err_e JNICALL
 382 ps_pdread(struct ps_prochandle *ph, psaddr_t  addr,
 383                    void *buf, size_t size) {
 384   return ph->ops->p_pread(ph, (uintptr_t) addr, buf, size)? PS_OK: PS_ERR;
 385 }
 386 
 387 // write "size" bytes of data to debuggee at address "addr"
 388 JNIEXPORT ps_err_e JNICALL
 389 ps_pdwrite(struct ps_prochandle *ph, psaddr_t addr,
 390                     const void *buf, size_t size) {
 391   return ph->ops->p_pwrite(ph, (uintptr_t)addr, buf, size)? PS_OK: PS_ERR;
 392 }
 393 
 394 // ------------------------------------------------------------------------
 395 // Functions below this point are not yet implemented. They are here only
 396 // to make the linker happy.
 397 
 398 JNIEXPORT ps_err_e JNICALL
 399 ps_lsetfpregs(struct ps_prochandle *ph, lwpid_t lid, const prfpregset_t *fpregs) {
 400   print_debug("ps_lsetfpregs not implemented\n");
 401   return PS_OK;
 402 }
 403 
 404 JNIEXPORT ps_err_e JNICALL
 405 ps_lsetregs(struct ps_prochandle *ph, lwpid_t lid, const prgregset_t gregset) {
 406   print_debug("ps_lsetregs not implemented\n");
 407   return PS_OK;
 408 }
 409 
 410 JNIEXPORT ps_err_e  JNICALL
 411 ps_lgetfpregs(struct  ps_prochandle  *ph,  lwpid_t lid, prfpregset_t *fpregs) {
 412   print_debug("ps_lgetfpregs not implemented\n");
 413   return PS_OK;
 414 }
 415 
 416 JNIEXPORT ps_err_e JNICALL
 417 ps_lgetregs(struct ps_prochandle *ph, lwpid_t lid, prgregset_t gregset) {
 418   print_debug("ps_lgetfpregs not implemented\n");
 419   return PS_OK;
 420 }
 421 






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