gdb/solib-target.c

   1 /* Definitions for targets which report shared library events.
   2
   3    Copyright (C) 2007-2020 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 "solib-target.h"
  27 #include <vector>
  28
  29 /* Private data for each loaded library.  */
  30 struct lm_info_target : public lm_info_base
  31 {
  32   /* The library's name.  The name is normally kept in the struct
  33      so_list; it is only here during XML parsing.  */
  34   std::string name;
  35
  36   /* The target can either specify segment bases or section bases, not
  37      both.  */
  38
  39   /* The base addresses for each independently relocatable segment of
  40      this shared library.  */
  41   std::vector<CORE_ADDR> segment_bases;
  42
  43   /* The base addresses for each independently allocatable,
  44      relocatable section of this shared library.  */
  45   std::vector<CORE_ADDR> section_bases;
  46
  47   /* The cached offsets for each section of this shared library,
  48      determined from SEGMENT_BASES, or SECTION_BASES.  */
  49   section_offsets offsets;
  50 };
  51
  52 typedef std::vector<std::unique_ptr<lm_info_target>> lm_info_vector;
  53
  54 #if !defined(HAVE_LIBEXPAT)
  55
  56 static lm_info_vector
  57 solib_target_parse_libraries (const char *library)
  58 {
  59   static int have_warned;
  60
  61   if (!have_warned)
  62     {
  63       have_warned = 1;
  64       warning (_("Can not parse XML library list; XML support was disabled "
  65                  "at compile time"));
  66     }
  67
  68   return lm_info_vector ();
  69 }
  70
  71 #else /* HAVE_LIBEXPAT */
  72
  73 #include "xml-support.h"
  74
  75 /* Handle the start of a <segment> element.  */
  76
  77 static void
  78 library_list_start_segment (struct gdb_xml_parser *parser,
  79                             const struct gdb_xml_element *element,
  80                             void *user_data,
  81                             std::vector<gdb_xml_value> &attributes)
  82 {
  83   lm_info_vector *list = (lm_info_vector *) user_data;
  84   lm_info_target *last = list->back ().get ();
  85   ULONGEST *address_p
  86     = (ULONGEST *) xml_find_attribute (attributes, "address")->value.get ();
  87   CORE_ADDR address = (CORE_ADDR) *address_p;
  88
  89   if (!last->section_bases.empty ())
  90     gdb_xml_error (parser,
  91                    _("Library list with both segments and sections"));
  92
  93   last->segment_bases.push_back (address);
  94 }
  95
  96 static void
  97 library_list_start_section (struct gdb_xml_parser *parser,
  98                             const struct gdb_xml_element *element,
  99                             void *user_data,
 100                             std::vector<gdb_xml_value> &attributes)
 101 {
 102   lm_info_vector *list = (lm_info_vector *) user_data;
 103   lm_info_target *last = list->back ().get ();
 104   ULONGEST *address_p
 105     = (ULONGEST *) xml_find_attribute (attributes, "address")->value.get ();
 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,
 121                             std::vector<gdb_xml_value> &attributes)
 122 {
 123   lm_info_vector *list = (lm_info_vector *) user_data;
 124   lm_info_target *item = new lm_info_target;
 125   item->name
 126     = (const char *) xml_find_attribute (attributes, "name")->value.get ();
 127
 128   list->emplace_back (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   lm_info_vector *list = (lm_info_vector *) user_data;
 137   lm_info_target *lm_info = list->back ().get ();
 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,
 150                          std::vector<gdb_xml_value> &attributes)
 151 {
 152   struct gdb_xml_value *version = xml_find_attribute (attributes, "version");
 153
 154   /* #FIXED attribute may be omitted, Expat returns NULL in such case.  */
 155   if (version != NULL)
 156     {
 157       const char *string = (const char *) version->value.get ();
 158
 159       if (strcmp (string, "1.0") != 0)
 160         gdb_xml_error (parser,
 161                        _("Library list has unsupported version \"%s\""),
 162                        string);
 163     }
 164 }
 165
 166 /* The allowed elements and attributes for an XML library list.
 167    The root element is a <library-list>.  */
 168
 169 static const struct gdb_xml_attribute segment_attributes[] = {
 170   { "address", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
 171   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 172 };
 173
 174 static const struct gdb_xml_attribute section_attributes[] = {
 175   { "address", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
 176   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 177 };
 178
 179 static const struct gdb_xml_element library_children[] = {
 180   { "segment", segment_attributes, NULL,
 181     GDB_XML_EF_REPEATABLE | GDB_XML_EF_OPTIONAL,
 182     library_list_start_segment, NULL },
 183   { "section", section_attributes, NULL,
 184     GDB_XML_EF_REPEATABLE | GDB_XML_EF_OPTIONAL,
 185     library_list_start_section, NULL },
 186   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 187 };
 188
 189 static const struct gdb_xml_attribute library_attributes[] = {
 190   { "name", GDB_XML_AF_NONE, NULL, NULL },
 191   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 192 };
 193
 194 static const struct gdb_xml_element library_list_children[] = {
 195   { "library", library_attributes, library_children,
 196     GDB_XML_EF_REPEATABLE | GDB_XML_EF_OPTIONAL,
 197     library_list_start_library, library_list_end_library },
 198   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 199 };
 200
 201 static const struct gdb_xml_attribute library_list_attributes[] = {
 202   { "version", GDB_XML_AF_OPTIONAL, NULL, NULL },
 203   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 204 };
 205
 206 static const struct gdb_xml_element library_list_elements[] = {
 207   { "library-list", library_list_attributes, library_list_children,
 208     GDB_XML_EF_NONE, library_list_start_list, NULL },
 209   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 210 };
 211
 212 static lm_info_vector
 213 solib_target_parse_libraries (const char *library)
 214 {
 215   lm_info_vector result;
 216
 217   if (gdb_xml_parse_quick (_("target library list"), "library-list.dtd",
 218                            library_list_elements, library, &result) == 0)
 219     {
 220       /* Parsed successfully.  */
 221       return result;
 222     }
 223
 224   result.clear ();
 225   return result;
 226 }
 227 #endif
 228
 229 static struct so_list *
 230 solib_target_current_sos (void)
 231 {
 232   struct so_list *new_solib, *start = NULL, *last = NULL;
 233
 234   /* Fetch the list of shared libraries.  */
 235   gdb::optional<gdb::char_vector> library_document
 236     = target_read_stralloc (current_top_target (), TARGET_OBJECT_LIBRARIES,
 237                             NULL);
 238   if (!library_document)
 239     return NULL;
 240
 241   /* Parse the list.  */
 242   lm_info_vector library_list
 243     = solib_target_parse_libraries (library_document->data ());
 244
 245   if (library_list.empty ())
 246     return NULL;
 247
 248   /* Build a struct so_list for each entry on the list.  */
 249   for (auto &&info : library_list)
 250     {
 251       new_solib = XCNEW (struct so_list);
 252       strncpy (new_solib->so_name, info->name.c_str (),
 253                SO_NAME_MAX_PATH_SIZE - 1);
 254       new_solib->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0';
 255       strncpy (new_solib->so_original_name, info->name.c_str (),
 256                SO_NAME_MAX_PATH_SIZE - 1);
 257       new_solib->so_original_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0';
 258
 259       /* We no longer need this copy of the name.  */
 260       info->name.clear ();
 261
 262       new_solib->lm_info = info.release ();
 263
 264       /* Add it to the list.  */
 265       if (!start)
 266         last = start = new_solib;
 267       else
 268         {
 269           last->next = new_solib;
 270           last = new_solib;
 271         }
 272     }
 273
 274   return start;
 275 }
 276
 277 static void
 278 solib_target_solib_create_inferior_hook (int from_tty)
 279 {
 280   /* Nothing needed.  */
 281 }
 282
 283 static void
 284 solib_target_clear_solib (void)
 285 {
 286   /* Nothing needed.  */
 287 }
 288
 289 static void
 290 solib_target_free_so (struct so_list *so)
 291 {
 292   lm_info_target *li = (lm_info_target *) so->lm_info;
 293
 294   gdb_assert (li->name.empty ());
 295
 296   delete li;
 297 }
 298
 299 static void
 300 solib_target_relocate_section_addresses (struct so_list *so,
 301                                          struct target_section *sec)
 302 {
 303   CORE_ADDR offset;
 304   lm_info_target *li = (lm_info_target *) so->lm_info;
 305
 306   /* Build the offset table only once per object file.  We can not do
 307      it any earlier, since we need to open the file first.  */
 308   if (li->offsets.empty ())
 309     {
 310       int num_sections = gdb_bfd_count_sections (so->abfd);
 311
 312       li->offsets.assign (num_sections, 0);
 313
 314       if (!li->section_bases.empty ())
 315         {
 316           int i;
 317           asection *sect;
 318           int num_alloc_sections = 0;
 319
 320           for (i = 0, sect = so->abfd->sections;
 321                sect != NULL;
 322                i++, sect = sect->next)
 323             if ((bfd_section_flags (sect) & SEC_ALLOC))
 324               num_alloc_sections++;
 325
 326           if (num_alloc_sections != li->section_bases.size ())
 327             warning (_("\
 328 Could not relocate shared library \"%s\": wrong number of ALLOC sections"),
 329                      so->so_name);
 330           else
 331             {
 332               int bases_index = 0;
 333               int found_range = 0;
 334
 335               so->addr_low = ~(CORE_ADDR) 0;
 336               so->addr_high = 0;
 337               for (i = 0, sect = so->abfd->sections;
 338                    sect != NULL;
 339                    i++, sect = sect->next)
 340                 {
 341                   if (!(bfd_section_flags (sect) & SEC_ALLOC))
 342                     continue;
 343                   if (bfd_section_size (sect) > 0)
 344                     {
 345                       CORE_ADDR low, high;
 346
 347                       low = li->section_bases[i];
 348                       high = low + bfd_section_size (sect) - 1;
 349
 350                       if (low < so->addr_low)
 351                         so->addr_low = low;
 352                       if (high > so->addr_high)
 353                         so->addr_high = high;
 354                       gdb_assert (so->addr_low <= so->addr_high);
 355                       found_range = 1;
 356                     }
 357                   li->offsets[i] = li->section_bases[bases_index];
 358                   bases_index++;
 359                 }
 360               if (!found_range)
 361                 so->addr_low = so->addr_high = 0;
 362               gdb_assert (so->addr_low <= so->addr_high);
 363             }
 364         }
 365       else if (!li->segment_bases.empty ())
 366         {
 367           struct symfile_segment_data *data;
 368
 369           data = get_symfile_segment_data (so->abfd);
 370           if (data == NULL)
 371             warning (_("\
 372 Could not relocate shared library \"%s\": no segments"), so->so_name);
 373           else
 374             {
 375               ULONGEST orig_delta;
 376               int i;
 377
 378               if (!symfile_map_offsets_to_segments (so->abfd, data,
 379                                                     li->offsets,
 380                                                     li->segment_bases.size (),
 381                                                     li->segment_bases.data ()))
 382                 warning (_("\
 383 Could not relocate shared library \"%s\": bad offsets"), so->so_name);
 384
 385               /* Find the range of addresses to report for this library in
 386                  "info sharedlibrary".  Report any consecutive segments
 387                  which were relocated as a single unit.  */
 388               gdb_assert (li->segment_bases.size () > 0);
 389               orig_delta = li->segment_bases[0] - data->segment_bases[0];
 390
 391               for (i = 1; i < data->num_segments; i++)
 392                 {
 393                   /* If we have run out of offsets, assume all
 394                      remaining segments have the same offset.  */
 395                   if (i >= li->segment_bases.size ())
 396                     continue;
 397
 398                   /* If this segment does not have the same offset, do
 399                      not include it in the library's range.  */
 400                   if (li->segment_bases[i] - data->segment_bases[i]
 401                       != orig_delta)
 402                     break;
 403                 }
 404
 405               so->addr_low = li->segment_bases[0];
 406               so->addr_high = (data->segment_bases[i - 1]
 407                                + data->segment_sizes[i - 1]
 408                                + orig_delta);
 409               gdb_assert (so->addr_low <= so->addr_high);
 410
 411               free_symfile_segment_data (data);
 412             }
 413         }
 414     }
 415
 416   offset = li->offsets[gdb_bfd_section_index (sec->the_bfd_section->owner,
 417                                               sec->the_bfd_section)];
 418   sec->addr += offset;
 419   sec->endaddr += offset;
 420 }
 421
 422 static int
 423 solib_target_open_symbol_file_object (int from_tty)
 424 {
 425   /* We can't locate the main symbol file based on the target's
 426      knowledge; the user has to specify it.  */
 427   return 0;
 428 }
 429
 430 static int
 431 solib_target_in_dynsym_resolve_code (CORE_ADDR pc)
 432 {
 433   /* We don't have a range of addresses for the dynamic linker; there
 434      may not be one in the program's address space.  So only report
 435      PLT entries (which may be import stubs).  */
 436   return in_plt_section (pc);
 437 }
 438
 439 struct target_so_ops solib_target_so_ops;
 440
 441 void
 442 _initialize_solib_target (void)
 443 {
 444   solib_target_so_ops.relocate_section_addresses
 445     = solib_target_relocate_section_addresses;
 446   solib_target_so_ops.free_so = solib_target_free_so;
 447   solib_target_so_ops.clear_solib = solib_target_clear_solib;
 448   solib_target_so_ops.solib_create_inferior_hook
 449     = solib_target_solib_create_inferior_hook;
 450   solib_target_so_ops.current_sos = solib_target_current_sos;
 451   solib_target_so_ops.open_symbol_file_object
 452     = solib_target_open_symbol_file_object;
 453   solib_target_so_ops.in_dynsym_resolve_code
 454     = solib_target_in_dynsym_resolve_code;
 455   solib_target_so_ops.bfd_open = solib_bfd_open;
 456
 457   /* Set current_target_so_ops to solib_target_so_ops if not already
 458      set.  */
 459   if (current_target_so_ops == 0)
 460     current_target_so_ops = &solib_target_so_ops;
 461 }