gdb/solib-target.c

   1 /* Definitions for targets which report shared library events.
   2
   3    Copyright (C) 2007-2017 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, VEC(gdb_xml_value_s) *attributes)
  83 {
  84   VEC(lm_info_target_p) **list = (VEC(lm_info_target_p) **) user_data;
  85   lm_info_target *last = VEC_last (lm_info_target_p, *list);
  86   ULONGEST *address_p
  87     = (ULONGEST *) xml_find_attribute (attributes, "address")->value;
  88   CORE_ADDR address = (CORE_ADDR) *address_p;
  89
  90   if (!last->section_bases.empty ())
  91     gdb_xml_error (parser,
  92                    _("Library list with both segments and sections"));
  93
  94   last->segment_bases.push_back (address);
  95 }
  96
  97 static void
  98 library_list_start_section (struct gdb_xml_parser *parser,
  99                             const struct gdb_xml_element *element,
 100                             void *user_data, VEC(gdb_xml_value_s) *attributes)
 101 {
 102   VEC(lm_info_target_p) **list = (VEC(lm_info_target_p) **) user_data;
 103   lm_info_target *last = VEC_last (lm_info_target_p, *list);
 104   ULONGEST *address_p
 105     = (ULONGEST *) xml_find_attribute (attributes, "address")->value;
 106   CORE_ADDR address = (CORE_ADDR) *address_p;
 107
 108   if (!last->segment_bases.empty ())
 109     gdb_xml_error (parser,
 110                    _("Library list with both segments and sections"));
 111
 112   last->section_bases.push_back (address);
 113 }
 114
 115 /* Handle the start of a <library> element.  */
 116
 117 static void
 118 library_list_start_library (struct gdb_xml_parser *parser,
 119                             const struct gdb_xml_element *element,
 120                             void *user_data, VEC(gdb_xml_value_s) *attributes)
 121 {
 122   VEC(lm_info_target_p) **list = (VEC(lm_info_target_p) **) user_data;
 123   lm_info_target *item = new lm_info_target;
 124   const char *name
 125     = (const char *) xml_find_attribute (attributes, "name")->value;
 126
 127   item->name = xstrdup (name);
 128   VEC_safe_push (lm_info_target_p, *list, item);
 129 }
 130
 131 static void
 132 library_list_end_library (struct gdb_xml_parser *parser,
 133                           const struct gdb_xml_element *element,
 134                           void *user_data, const char *body_text)
 135 {
 136   VEC(lm_info_target_p) **list = (VEC(lm_info_target_p) **) user_data;
 137   lm_info_target *lm_info = VEC_last (lm_info_target_p, *list);
 138
 139   if (lm_info->segment_bases.empty () && lm_info->section_bases.empty ())
 140     gdb_xml_error (parser, _("No segment or section bases defined"));
 141 }
 142
 143
 144 /* Handle the start of a <library-list> element.  */
 145
 146 static void
 147 library_list_start_list (struct gdb_xml_parser *parser,
 148                          const struct gdb_xml_element *element,
 149                          void *user_data, VEC(gdb_xml_value_s) *attributes)
 150 {
 151   struct gdb_xml_value *version = xml_find_attribute (attributes, "version");
 152
 153   /* #FIXED attribute may be omitted, Expat returns NULL in such case.  */
 154   if (version != NULL)
 155     {
 156       const char *string = (const char *) version->value;
 157
 158       if (strcmp (string, "1.0") != 0)
 159         gdb_xml_error (parser,
 160                        _("Library list has unsupported version \"%s\""),
 161                        string);
 162     }
 163 }
 164
 165 /* Discard the constructed library list.  */
 166
 167 static void
 168 solib_target_free_library_list (void *p)
 169 {
 170   VEC(lm_info_target_p) **result = (VEC(lm_info_target_p) **) p;
 171   lm_info_target *info;
 172   int ix;
 173
 174   for (ix = 0; VEC_iterate (lm_info_target_p, *result, ix, info); ix++)
 175     delete info;
 176
 177   VEC_free (lm_info_target_p, *result);
 178   *result = NULL;
 179 }
 180
 181 /* The allowed elements and attributes for an XML library list.
 182    The root element is a <library-list>.  */
 183
 184 static const struct gdb_xml_attribute segment_attributes[] = {
 185   { "address", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
 186   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 187 };
 188
 189 static const struct gdb_xml_attribute section_attributes[] = {
 190   { "address", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
 191   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 192 };
 193
 194 static const struct gdb_xml_element library_children[] = {
 195   { "segment", segment_attributes, NULL,
 196     GDB_XML_EF_REPEATABLE | GDB_XML_EF_OPTIONAL,
 197     library_list_start_segment, NULL },
 198   { "section", section_attributes, NULL,
 199     GDB_XML_EF_REPEATABLE | GDB_XML_EF_OPTIONAL,
 200     library_list_start_section, NULL },
 201   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 202 };
 203
 204 static const struct gdb_xml_attribute library_attributes[] = {
 205   { "name", GDB_XML_AF_NONE, NULL, NULL },
 206   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 207 };
 208
 209 static const struct gdb_xml_element library_list_children[] = {
 210   { "library", library_attributes, library_children,
 211     GDB_XML_EF_REPEATABLE | GDB_XML_EF_OPTIONAL,
 212     library_list_start_library, library_list_end_library },
 213   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 214 };
 215
 216 static const struct gdb_xml_attribute library_list_attributes[] = {
 217   { "version", GDB_XML_AF_OPTIONAL, NULL, NULL },
 218   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 219 };
 220
 221 static const struct gdb_xml_element library_list_elements[] = {
 222   { "library-list", library_list_attributes, library_list_children,
 223     GDB_XML_EF_NONE, library_list_start_list, NULL },
 224   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 225 };
 226
 227 static VEC(lm_info_target_p) *
 228 solib_target_parse_libraries (const char *library)
 229 {
 230   VEC(lm_info_target_p) *result = NULL;
 231   struct cleanup *back_to = make_cleanup (solib_target_free_library_list,
 232                                           &result);
 233
 234   if (gdb_xml_parse_quick (_("target library list"), "library-list.dtd",
 235                            library_list_elements, library, &result) == 0)
 236     {
 237       /* Parsed successfully, keep the result.  */
 238       discard_cleanups (back_to);
 239       return result;
 240     }
 241
 242   do_cleanups (back_to);
 243   return NULL;
 244 }
 245 #endif
 246
 247 static struct so_list *
 248 solib_target_current_sos (void)
 249 {
 250   struct so_list *new_solib, *start = NULL, *last = NULL;
 251   char *library_document;
 252   struct cleanup *old_chain;
 253   VEC(lm_info_target_p) *library_list;
 254   lm_info_target *info;
 255   int ix;
 256
 257   /* Fetch the list of shared libraries.  */
 258   library_document = target_read_stralloc (&current_target,
 259                                            TARGET_OBJECT_LIBRARIES,
 260                                            NULL);
 261   if (library_document == NULL)
 262     return NULL;
 263
 264   /* solib_target_parse_libraries may throw, so we use a cleanup.  */
 265   old_chain = make_cleanup (xfree, library_document);
 266
 267   /* Parse the list.  */
 268   library_list = solib_target_parse_libraries (library_document);
 269
 270   /* library_document string is not needed behind this point.  */
 271   do_cleanups (old_chain);
 272
 273   if (library_list == NULL)
 274     return NULL;
 275
 276   /* Build a struct so_list for each entry on the list.  */
 277   for (ix = 0; VEC_iterate (lm_info_target_p, library_list, ix, info); ix++)
 278     {
 279       new_solib = XCNEW (struct so_list);
 280       strncpy (new_solib->so_name, info->name.c_str (),
 281                SO_NAME_MAX_PATH_SIZE - 1);
 282       new_solib->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0';
 283       strncpy (new_solib->so_original_name, info->name.c_str (),
 284                SO_NAME_MAX_PATH_SIZE - 1);
 285       new_solib->so_original_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0';
 286       new_solib->lm_info = info;
 287
 288       /* We no longer need this copy of the name.  */
 289       info->name.clear ();
 290
 291       /* Add it to the list.  */
 292       if (!start)
 293         last = start = new_solib;
 294       else
 295         {
 296           last->next = new_solib;
 297           last = new_solib;
 298         }
 299     }
 300
 301   /* Free the library list, but not its members.  */
 302   VEC_free (lm_info_target_p, library_list);
 303
 304   return start;
 305 }
 306
 307 static void
 308 solib_target_solib_create_inferior_hook (int from_tty)
 309 {
 310   /* Nothing needed.  */
 311 }
 312
 313 static void
 314 solib_target_clear_solib (void)
 315 {
 316   /* Nothing needed.  */
 317 }
 318
 319 static void
 320 solib_target_free_so (struct so_list *so)
 321 {
 322   lm_info_target *li = (lm_info_target *) so->lm_info;
 323
 324   gdb_assert (li->name.empty ());
 325
 326   delete li;
 327 }
 328
 329 static void
 330 solib_target_relocate_section_addresses (struct so_list *so,
 331                                          struct target_section *sec)
 332 {
 333   CORE_ADDR offset;
 334   lm_info_target *li = (lm_info_target *) so->lm_info;
 335
 336   /* Build the offset table only once per object file.  We can not do
 337      it any earlier, since we need to open the file first.  */
 338   if (li->offsets == NULL)
 339     {
 340       int num_sections = gdb_bfd_count_sections (so->abfd);
 341
 342       li->offsets
 343         = ((struct section_offsets *)
 344            xzalloc (SIZEOF_N_SECTION_OFFSETS (num_sections)));
 345
 346       if (!li->section_bases.empty ())
 347         {
 348           int i;
 349           asection *sect;
 350           int num_alloc_sections = 0;
 351
 352           for (i = 0, sect = so->abfd->sections;
 353                sect != NULL;
 354                i++, sect = sect->next)
 355             if ((bfd_get_section_flags (so->abfd, sect) & SEC_ALLOC))
 356               num_alloc_sections++;
 357
 358           if (num_alloc_sections != li->section_bases.size ())
 359             warning (_("\
 360 Could not relocate shared library \"%s\": wrong number of ALLOC sections"),
 361                      so->so_name);
 362           else
 363             {
 364               int bases_index = 0;
 365               int found_range = 0;
 366
 367               so->addr_low = ~(CORE_ADDR) 0;
 368               so->addr_high = 0;
 369               for (i = 0, sect = so->abfd->sections;
 370                    sect != NULL;
 371                    i++, sect = sect->next)
 372                 {
 373                   if (!(bfd_get_section_flags (so->abfd, sect) & SEC_ALLOC))
 374                     continue;
 375                   if (bfd_section_size (so->abfd, sect) > 0)
 376                     {
 377                       CORE_ADDR low, high;
 378
 379                       low = li->section_bases[i];
 380                       high = low + bfd_section_size (so->abfd, sect) - 1;
 381
 382                       if (low < so->addr_low)
 383                         so->addr_low = low;
 384                       if (high > so->addr_high)
 385                         so->addr_high = high;
 386                       gdb_assert (so->addr_low <= so->addr_high);
 387                       found_range = 1;
 388                     }
 389                   li->offsets->offsets[i] = li->section_bases[bases_index];
 390                   bases_index++;
 391                 }
 392               if (!found_range)
 393                 so->addr_low = so->addr_high = 0;
 394               gdb_assert (so->addr_low <= so->addr_high);
 395             }
 396         }
 397       else if (!li->segment_bases.empty ())
 398         {
 399           struct symfile_segment_data *data;
 400
 401           data = get_symfile_segment_data (so->abfd);
 402           if (data == NULL)
 403             warning (_("\
 404 Could not relocate shared library \"%s\": no segments"), so->so_name);
 405           else
 406             {
 407               ULONGEST orig_delta;
 408               int i;
 409
 410               if (!symfile_map_offsets_to_segments (so->abfd, data, li->offsets,
 411                                                     li->segment_bases.size (),
 412                                                     li->segment_bases.data ()))
 413                 warning (_("\
 414 Could not relocate shared library \"%s\": bad offsets"), so->so_name);
 415
 416               /* Find the range of addresses to report for this library in
 417                  "info sharedlibrary".  Report any consecutive segments
 418                  which were relocated as a single unit.  */
 419               gdb_assert (li->segment_bases.size () > 0);
 420               orig_delta = li->segment_bases[0] - data->segment_bases[0];
 421
 422               for (i = 1; i < data->num_segments; i++)
 423                 {
 424                   /* If we have run out of offsets, assume all
 425                      remaining segments have the same offset.  */
 426                   if (i >= li->segment_bases.size ())
 427                     continue;
 428
 429                   /* If this segment does not have the same offset, do
 430                      not include it in the library's range.  */
 431                   if (li->segment_bases[i] - data->segment_bases[i]
 432                       != orig_delta)
 433                     break;
 434                 }
 435
 436               so->addr_low = li->segment_bases[0];
 437               so->addr_high = (data->segment_bases[i - 1]
 438                                + data->segment_sizes[i - 1]
 439                                + orig_delta);
 440               gdb_assert (so->addr_low <= so->addr_high);
 441
 442               free_symfile_segment_data (data);
 443             }
 444         }
 445     }
 446
 447   offset = li->offsets->offsets[gdb_bfd_section_index
 448                                 (sec->the_bfd_section->owner,
 449                                  sec->the_bfd_section)];
 450   sec->addr += offset;
 451   sec->endaddr += offset;
 452 }
 453
 454 static int
 455 solib_target_open_symbol_file_object (int from_tty)
 456 {
 457   /* We can't locate the main symbol file based on the target's
 458      knowledge; the user has to specify it.  */
 459   return 0;
 460 }
 461
 462 static int
 463 solib_target_in_dynsym_resolve_code (CORE_ADDR pc)
 464 {
 465   /* We don't have a range of addresses for the dynamic linker; there
 466      may not be one in the program's address space.  So only report
 467      PLT entries (which may be import stubs).  */
 468   return in_plt_section (pc);
 469 }
 470
 471 struct target_so_ops solib_target_so_ops;
 472
 473 void
 474 _initialize_solib_target (void)
 475 {
 476   solib_target_so_ops.relocate_section_addresses
 477     = solib_target_relocate_section_addresses;
 478   solib_target_so_ops.free_so = solib_target_free_so;
 479   solib_target_so_ops.clear_solib = solib_target_clear_solib;
 480   solib_target_so_ops.solib_create_inferior_hook
 481     = solib_target_solib_create_inferior_hook;
 482   solib_target_so_ops.current_sos = solib_target_current_sos;
 483   solib_target_so_ops.open_symbol_file_object
 484     = solib_target_open_symbol_file_object;
 485   solib_target_so_ops.in_dynsym_resolve_code
 486     = solib_target_in_dynsym_resolve_code;
 487   solib_target_so_ops.bfd_open = solib_bfd_open;
 488
 489   /* Set current_target_so_ops to solib_target_so_ops if not already
 490      set.  */
 491   if (current_target_so_ops == 0)
 492     current_target_so_ops = &solib_target_so_ops;
 493 }