gdb/solib-target.c

   1 /* Definitions for targets which report shared library events.
   2
   3    Copyright (C) 2007-2019 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include "defs.h"
  21 #include "objfiles.h"
  22 #include "solist.h"
  23 #include "symtab.h"
  24 #include "symfile.h"
  25 #include "target.h"
  26 #include "vec.h"
  27 #include "solib-target.h"
  28 #include <vector>
  29
  30 /* Private data for each loaded library.  */
  31 struct lm_info_target : public lm_info_base
  32 {
  33   /* The library's name.  The name is normally kept in the struct
  34      so_list; it is only here during XML parsing.  */
  35   std::string name;
  36
  37   /* The target can either specify segment bases or section bases, not
  38      both.  */
  39
  40   /* The base addresses for each independently relocatable segment of
  41      this shared library.  */
  42   std::vector<CORE_ADDR> segment_bases;
  43
  44   /* The base addresses for each independently allocatable,
  45      relocatable section of this shared library.  */
  46   std::vector<CORE_ADDR> section_bases;
  47
  48   /* The cached offsets for each section of this shared library,
  49      determined from SEGMENT_BASES, or SECTION_BASES.  */
  50   section_offsets *offsets = NULL;
  51 };
  52
  53 typedef lm_info_target *lm_info_target_p;
  54 DEF_VEC_P(lm_info_target_p);
  55
  56 #if !defined(HAVE_LIBEXPAT)
  57
  58 static VEC(lm_info_target_p) *
  59 solib_target_parse_libraries (const char *library)
  60 {
  61   static int have_warned;
  62
  63   if (!have_warned)
  64     {
  65       have_warned = 1;
  66       warning (_("Can not parse XML library list; XML support was disabled "
  67                  "at compile time"));
  68     }
  69
  70   return NULL;
  71 }
  72
  73 #else /* HAVE_LIBEXPAT */
  74
  75 #include "xml-support.h"
  76
  77 /* Handle the start of a <segment> element.  */
  78
  79 static void
  80 library_list_start_segment (struct gdb_xml_parser *parser,
  81                             const struct gdb_xml_element *element,
  82                             void *user_data,
  83                             std::vector<gdb_xml_value> &attributes)
  84 {
  85   VEC(lm_info_target_p) **list = (VEC(lm_info_target_p) **) user_data;
  86   lm_info_target *last = VEC_last (lm_info_target_p, *list);
  87   ULONGEST *address_p
  88     = (ULONGEST *) xml_find_attribute (attributes, "address")->value.get ();
  89   CORE_ADDR address = (CORE_ADDR) *address_p;
  90
  91   if (!last->section_bases.empty ())
  92     gdb_xml_error (parser,
  93                    _("Library list with both segments and sections"));
  94
  95   last->segment_bases.push_back (address);
  96 }
  97
  98 static void
  99 library_list_start_section (struct gdb_xml_parser *parser,
 100                             const struct gdb_xml_element *element,
 101                             void *user_data,
 102                             std::vector<gdb_xml_value> &attributes)
 103 {
 104   VEC(lm_info_target_p) **list = (VEC(lm_info_target_p) **) user_data;
 105   lm_info_target *last = VEC_last (lm_info_target_p, *list);
 106   ULONGEST *address_p
 107     = (ULONGEST *) xml_find_attribute (attributes, "address")->value.get ();
 108   CORE_ADDR address = (CORE_ADDR) *address_p;
 109
 110   if (!last->segment_bases.empty ())
 111     gdb_xml_error (parser,
 112                    _("Library list with both segments and sections"));
 113
 114   last->section_bases.push_back (address);
 115 }
 116
 117 /* Handle the start of a <library> element.  */
 118
 119 static void
 120 library_list_start_library (struct gdb_xml_parser *parser,
 121                             const struct gdb_xml_element *element,
 122                             void *user_data,
 123                             std::vector<gdb_xml_value> &attributes)
 124 {
 125   VEC(lm_info_target_p) **list = (VEC(lm_info_target_p) **) user_data;
 126   lm_info_target *item = new lm_info_target;
 127   const char *name
 128     = (const char *) xml_find_attribute (attributes, "name")->value.get ();
 129
 130   item->name = xstrdup (name);
 131   VEC_safe_push (lm_info_target_p, *list, item);
 132 }
 133
 134 static void
 135 library_list_end_library (struct gdb_xml_parser *parser,
 136                           const struct gdb_xml_element *element,
 137                           void *user_data, const char *body_text)
 138 {
 139   VEC(lm_info_target_p) **list = (VEC(lm_info_target_p) **) user_data;
 140   lm_info_target *lm_info = VEC_last (lm_info_target_p, *list);
 141
 142   if (lm_info->segment_bases.empty () && lm_info->section_bases.empty ())
 143     gdb_xml_error (parser, _("No segment or section bases defined"));
 144 }
 145
 146
 147 /* Handle the start of a <library-list> element.  */
 148
 149 static void
 150 library_list_start_list (struct gdb_xml_parser *parser,
 151                          const struct gdb_xml_element *element,
 152                          void *user_data,
 153                          std::vector<gdb_xml_value> &attributes)
 154 {
 155   struct gdb_xml_value *version = xml_find_attribute (attributes, "version");
 156
 157   /* #FIXED attribute may be omitted, Expat returns NULL in such case.  */
 158   if (version != NULL)
 159     {
 160       const char *string = (const char *) version->value.get ();
 161
 162       if (strcmp (string, "1.0") != 0)
 163         gdb_xml_error (parser,
 164                        _("Library list has unsupported version \"%s\""),
 165                        string);
 166     }
 167 }
 168
 169 /* Discard the constructed library list.  */
 170
 171 static void
 172 solib_target_free_library_list (void *p)
 173 {
 174   VEC(lm_info_target_p) **result = (VEC(lm_info_target_p) **) p;
 175   lm_info_target *info;
 176   int ix;
 177
 178   for (ix = 0; VEC_iterate (lm_info_target_p, *result, ix, info); ix++)
 179     delete info;
 180
 181   VEC_free (lm_info_target_p, *result);
 182   *result = NULL;
 183 }
 184
 185 /* The allowed elements and attributes for an XML library list.
 186    The root element is a <library-list>.  */
 187
 188 static const struct gdb_xml_attribute segment_attributes[] = {
 189   { "address", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
 190   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 191 };
 192
 193 static const struct gdb_xml_attribute section_attributes[] = {
 194   { "address", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
 195   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 196 };
 197
 198 static const struct gdb_xml_element library_children[] = {
 199   { "segment", segment_attributes, NULL,
 200     GDB_XML_EF_REPEATABLE | GDB_XML_EF_OPTIONAL,
 201     library_list_start_segment, NULL },
 202   { "section", section_attributes, NULL,
 203     GDB_XML_EF_REPEATABLE | GDB_XML_EF_OPTIONAL,
 204     library_list_start_section, NULL },
 205   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 206 };
 207
 208 static const struct gdb_xml_attribute library_attributes[] = {
 209   { "name", GDB_XML_AF_NONE, NULL, NULL },
 210   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 211 };
 212
 213 static const struct gdb_xml_element library_list_children[] = {
 214   { "library", library_attributes, library_children,
 215     GDB_XML_EF_REPEATABLE | GDB_XML_EF_OPTIONAL,
 216     library_list_start_library, library_list_end_library },
 217   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 218 };
 219
 220 static const struct gdb_xml_attribute library_list_attributes[] = {
 221   { "version", GDB_XML_AF_OPTIONAL, NULL, NULL },
 222   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 223 };
 224
 225 static const struct gdb_xml_element library_list_elements[] = {
 226   { "library-list", library_list_attributes, library_list_children,
 227     GDB_XML_EF_NONE, library_list_start_list, NULL },
 228   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 229 };
 230
 231 static VEC(lm_info_target_p) *
 232 solib_target_parse_libraries (const char *library)
 233 {
 234   VEC(lm_info_target_p) *result = NULL;
 235   struct cleanup *back_to = make_cleanup (solib_target_free_library_list,
 236                                           &result);
 237
 238   if (gdb_xml_parse_quick (_("target library list"), "library-list.dtd",
 239                            library_list_elements, library, &result) == 0)
 240     {
 241       /* Parsed successfully, keep the result.  */
 242       discard_cleanups (back_to);
 243       return result;
 244     }
 245
 246   do_cleanups (back_to);
 247   return NULL;
 248 }
 249 #endif
 250
 251 static struct so_list *
 252 solib_target_current_sos (void)
 253 {
 254   struct so_list *new_solib, *start = NULL, *last = NULL;
 255   VEC(lm_info_target_p) *library_list;
 256   lm_info_target *info;
 257   int ix;
 258
 259   /* Fetch the list of shared libraries.  */
 260   gdb::optional<gdb::char_vector> library_document
 261     = target_read_stralloc (current_top_target (), TARGET_OBJECT_LIBRARIES,
 262                             NULL);
 263   if (!library_document)
 264     return NULL;
 265
 266   /* Parse the list.  */
 267   library_list = solib_target_parse_libraries (library_document->data ());
 268
 269   if (library_list == NULL)
 270     return NULL;
 271
 272   /* Build a struct so_list for each entry on the list.  */
 273   for (ix = 0; VEC_iterate (lm_info_target_p, library_list, ix, info); ix++)
 274     {
 275       new_solib = XCNEW (struct so_list);
 276       strncpy (new_solib->so_name, info->name.c_str (),
 277                SO_NAME_MAX_PATH_SIZE - 1);
 278       new_solib->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0';
 279       strncpy (new_solib->so_original_name, info->name.c_str (),
 280                SO_NAME_MAX_PATH_SIZE - 1);
 281       new_solib->so_original_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0';
 282       new_solib->lm_info = info;
 283
 284       /* We no longer need this copy of the name.  */
 285       info->name.clear ();
 286
 287       /* Add it to the list.  */
 288       if (!start)
 289         last = start = new_solib;
 290       else
 291         {
 292           last->next = new_solib;
 293           last = new_solib;
 294         }
 295     }
 296
 297   /* Free the library list, but not its members.  */
 298   VEC_free (lm_info_target_p, library_list);
 299
 300   return start;
 301 }
 302
 303 static void
 304 solib_target_solib_create_inferior_hook (int from_tty)
 305 {
 306   /* Nothing needed.  */
 307 }
 308
 309 static void
 310 solib_target_clear_solib (void)
 311 {
 312   /* Nothing needed.  */
 313 }
 314
 315 static void
 316 solib_target_free_so (struct so_list *so)
 317 {
 318   lm_info_target *li = (lm_info_target *) so->lm_info;
 319
 320   gdb_assert (li->name.empty ());
 321
 322   delete li;
 323 }
 324
 325 static void
 326 solib_target_relocate_section_addresses (struct so_list *so,
 327                                          struct target_section *sec)
 328 {
 329   CORE_ADDR offset;
 330   lm_info_target *li = (lm_info_target *) so->lm_info;
 331
 332   /* Build the offset table only once per object file.  We can not do
 333      it any earlier, since we need to open the file first.  */
 334   if (li->offsets == NULL)
 335     {
 336       int num_sections = gdb_bfd_count_sections (so->abfd);
 337
 338       li->offsets
 339         = ((struct section_offsets *)
 340            xzalloc (SIZEOF_N_SECTION_OFFSETS (num_sections)));
 341
 342       if (!li->section_bases.empty ())
 343         {
 344           int i;
 345           asection *sect;
 346           int num_alloc_sections = 0;
 347
 348           for (i = 0, sect = so->abfd->sections;
 349                sect != NULL;
 350                i++, sect = sect->next)
 351             if ((bfd_get_section_flags (so->abfd, sect) & SEC_ALLOC))
 352               num_alloc_sections++;
 353
 354           if (num_alloc_sections != li->section_bases.size ())
 355             warning (_("\
 356 Could not relocate shared library \"%s\": wrong number of ALLOC sections"),
 357                      so->so_name);
 358           else
 359             {
 360               int bases_index = 0;
 361               int found_range = 0;
 362
 363               so->addr_low = ~(CORE_ADDR) 0;
 364               so->addr_high = 0;
 365               for (i = 0, sect = so->abfd->sections;
 366                    sect != NULL;
 367                    i++, sect = sect->next)
 368                 {
 369                   if (!(bfd_get_section_flags (so->abfd, sect) & SEC_ALLOC))
 370                     continue;
 371                   if (bfd_section_size (so->abfd, sect) > 0)
 372                     {
 373                       CORE_ADDR low, high;
 374
 375                       low = li->section_bases[i];
 376                       high = low + bfd_section_size (so->abfd, sect) - 1;
 377
 378                       if (low < so->addr_low)
 379                         so->addr_low = low;
 380                       if (high > so->addr_high)
 381                         so->addr_high = high;
 382                       gdb_assert (so->addr_low <= so->addr_high);
 383                       found_range = 1;
 384                     }
 385                   li->offsets->offsets[i] = li->section_bases[bases_index];
 386                   bases_index++;
 387                 }
 388               if (!found_range)
 389                 so->addr_low = so->addr_high = 0;
 390               gdb_assert (so->addr_low <= so->addr_high);
 391             }
 392         }
 393       else if (!li->segment_bases.empty ())
 394         {
 395           struct symfile_segment_data *data;
 396
 397           data = get_symfile_segment_data (so->abfd);
 398           if (data == NULL)
 399             warning (_("\
 400 Could not relocate shared library \"%s\": no segments"), so->so_name);
 401           else
 402             {
 403               ULONGEST orig_delta;
 404               int i;
 405
 406               if (!symfile_map_offsets_to_segments (so->abfd, data, li->offsets,
 407                                                     li->segment_bases.size (),
 408                                                     li->segment_bases.data ()))
 409                 warning (_("\
 410 Could not relocate shared library \"%s\": bad offsets"), so->so_name);
 411
 412               /* Find the range of addresses to report for this library in
 413                  "info sharedlibrary".  Report any consecutive segments
 414                  which were relocated as a single unit.  */
 415               gdb_assert (li->segment_bases.size () > 0);
 416               orig_delta = li->segment_bases[0] - data->segment_bases[0];
 417
 418               for (i = 1; i < data->num_segments; i++)
 419                 {
 420                   /* If we have run out of offsets, assume all
 421                      remaining segments have the same offset.  */
 422                   if (i >= li->segment_bases.size ())
 423                     continue;
 424
 425                   /* If this segment does not have the same offset, do
 426                      not include it in the library's range.  */
 427                   if (li->segment_bases[i] - data->segment_bases[i]
 428                       != orig_delta)
 429                     break;
 430                 }
 431
 432               so->addr_low = li->segment_bases[0];
 433               so->addr_high = (data->segment_bases[i - 1]
 434                                + data->segment_sizes[i - 1]
 435                                + orig_delta);
 436               gdb_assert (so->addr_low <= so->addr_high);
 437
 438               free_symfile_segment_data (data);
 439             }
 440         }
 441     }
 442
 443   offset = li->offsets->offsets[gdb_bfd_section_index
 444                                 (sec->the_bfd_section->owner,
 445                                  sec->the_bfd_section)];
 446   sec->addr += offset;
 447   sec->endaddr += offset;
 448 }
 449
 450 static int
 451 solib_target_open_symbol_file_object (int from_tty)
 452 {
 453   /* We can't locate the main symbol file based on the target's
 454      knowledge; the user has to specify it.  */
 455   return 0;
 456 }
 457
 458 static int
 459 solib_target_in_dynsym_resolve_code (CORE_ADDR pc)
 460 {
 461   /* We don't have a range of addresses for the dynamic linker; there
 462      may not be one in the program's address space.  So only report
 463      PLT entries (which may be import stubs).  */
 464   return in_plt_section (pc);
 465 }
 466
 467 struct target_so_ops solib_target_so_ops;
 468
 469 void
 470 _initialize_solib_target (void)
 471 {
 472   solib_target_so_ops.relocate_section_addresses
 473     = solib_target_relocate_section_addresses;
 474   solib_target_so_ops.free_so = solib_target_free_so;
 475   solib_target_so_ops.clear_solib = solib_target_clear_solib;
 476   solib_target_so_ops.solib_create_inferior_hook
 477     = solib_target_solib_create_inferior_hook;
 478   solib_target_so_ops.current_sos = solib_target_current_sos;
 479   solib_target_so_ops.open_symbol_file_object
 480     = solib_target_open_symbol_file_object;
 481   solib_target_so_ops.in_dynsym_resolve_code
 482     = solib_target_in_dynsym_resolve_code;
 483   solib_target_so_ops.bfd_open = solib_bfd_open;
 484
 485   /* Set current_target_so_ops to solib_target_so_ops if not already
 486      set.  */
 487   if (current_target_so_ops == 0)
 488     current_target_so_ops = &solib_target_so_ops;
 489 }