gdb/solib-target.c

   1 /* Definitions for targets which report shared library events.
   2
   3    Copyright (C) 2007-2023 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 #include "inferior.h"
  29
  30 /* Private data for each loaded library.  */
  31 struct lm_info_target final : public lm_info
  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;
  51 };
  52
  53 using lm_info_target_up = std::unique_ptr<lm_info_target>;
  54
  55 #if !defined(HAVE_LIBEXPAT)
  56
  57 static std::vector<lm_info_target_up>
  58 solib_target_parse_libraries (const char *library)
  59 {
  60   static int have_warned;
  61
  62   if (!have_warned)
  63     {
  64       have_warned = 1;
  65       warning (_("Can not parse XML library list; XML support was disabled "
  66                  "at compile time"));
  67     }
  68
  69   return {};
  70 }
  71
  72 #else /* HAVE_LIBEXPAT */
  73
  74 #include "xml-support.h"
  75
  76 /* Handle the start of a <segment> element.  */
  77
  78 static void
  79 library_list_start_segment (struct gdb_xml_parser *parser,
  80                             const struct gdb_xml_element *element,
  81                             void *user_data,
  82                             std::vector<gdb_xml_value> &attributes)
  83 {
  84   auto *list = (std::vector<lm_info_target_up> *) user_data;
  85   lm_info_target *last = list->back ().get ();
  86   ULONGEST *address_p
  87     = (ULONGEST *) xml_find_attribute (attributes, "address")->value.get ();
  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,
 101                             std::vector<gdb_xml_value> &attributes)
 102 {
 103   auto *list = (std::vector<lm_info_target_up> *) user_data;
 104   lm_info_target *last = list->back ().get ();
 105   ULONGEST *address_p
 106     = (ULONGEST *) xml_find_attribute (attributes, "address")->value.get ();
 107   CORE_ADDR address = (CORE_ADDR) *address_p;
 108
 109   if (!last->segment_bases.empty ())
 110     gdb_xml_error (parser,
 111                    _("Library list with both segments and sections"));
 112
 113   last->section_bases.push_back (address);
 114 }
 115
 116 /* Handle the start of a <library> element.  */
 117
 118 static void
 119 library_list_start_library (struct gdb_xml_parser *parser,
 120                             const struct gdb_xml_element *element,
 121                             void *user_data,
 122                             std::vector<gdb_xml_value> &attributes)
 123 {
 124   auto *list = (std::vector<lm_info_target_up> *) user_data;
 125   lm_info_target *item = new lm_info_target;
 126   item->name
 127     = (const char *) xml_find_attribute (attributes, "name")->value.get ();
 128
 129   list->emplace_back (item);
 130 }
 131
 132 static void
 133 library_list_end_library (struct gdb_xml_parser *parser,
 134                           const struct gdb_xml_element *element,
 135                           void *user_data, const char *body_text)
 136 {
 137   auto *list = (std::vector<lm_info_target_up> *) user_data;
 138   lm_info_target *lm_info = list->back ().get ();
 139
 140   if (lm_info->segment_bases.empty () && lm_info->section_bases.empty ())
 141     gdb_xml_error (parser, _("No segment or section bases defined"));
 142 }
 143
 144
 145 /* Handle the start of a <library-list> element.  */
 146
 147 static void
 148 library_list_start_list (struct gdb_xml_parser *parser,
 149                          const struct gdb_xml_element *element,
 150                          void *user_data,
 151                          std::vector<gdb_xml_value> &attributes)
 152 {
 153   struct gdb_xml_value *version = xml_find_attribute (attributes, "version");
 154
 155   /* #FIXED attribute may be omitted, Expat returns NULL in such case.  */
 156   if (version != NULL)
 157     {
 158       const char *string = (const char *) version->value.get ();
 159
 160       if (strcmp (string, "1.0") != 0)
 161         gdb_xml_error (parser,
 162                        _("Library list has unsupported version \"%s\""),
 163                        string);
 164     }
 165 }
 166
 167 /* The allowed elements and attributes for an XML library list.
 168    The root element is a <library-list>.  */
 169
 170 static const struct gdb_xml_attribute segment_attributes[] = {
 171   { "address", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
 172   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 173 };
 174
 175 static const struct gdb_xml_attribute section_attributes[] = {
 176   { "address", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
 177   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 178 };
 179
 180 static const struct gdb_xml_element library_children[] = {
 181   { "segment", segment_attributes, NULL,
 182     GDB_XML_EF_REPEATABLE | GDB_XML_EF_OPTIONAL,
 183     library_list_start_segment, NULL },
 184   { "section", section_attributes, NULL,
 185     GDB_XML_EF_REPEATABLE | GDB_XML_EF_OPTIONAL,
 186     library_list_start_section, NULL },
 187   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 188 };
 189
 190 static const struct gdb_xml_attribute library_attributes[] = {
 191   { "name", GDB_XML_AF_NONE, NULL, NULL },
 192   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 193 };
 194
 195 static const struct gdb_xml_element library_list_children[] = {
 196   { "library", library_attributes, library_children,
 197     GDB_XML_EF_REPEATABLE | GDB_XML_EF_OPTIONAL,
 198     library_list_start_library, library_list_end_library },
 199   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 200 };
 201
 202 static const struct gdb_xml_attribute library_list_attributes[] = {
 203   { "version", GDB_XML_AF_OPTIONAL, NULL, NULL },
 204   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 205 };
 206
 207 static const struct gdb_xml_element library_list_elements[] = {
 208   { "library-list", library_list_attributes, library_list_children,
 209     GDB_XML_EF_NONE, library_list_start_list, NULL },
 210   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 211 };
 212
 213 static std::vector<lm_info_target_up>
 214 solib_target_parse_libraries (const char *library)
 215 {
 216   std::vector<lm_info_target_up> result;
 217
 218   if (gdb_xml_parse_quick (_("target library list"), "library-list.dtd",
 219                            library_list_elements, library, &result) == 0)
 220     {
 221       /* Parsed successfully.  */
 222       return result;
 223     }
 224
 225   result.clear ();
 226   return result;
 227 }
 228 #endif
 229
 230 static intrusive_list<shobj>
 231 solib_target_current_sos (void)
 232 {
 233   intrusive_list<shobj> sos;
 234
 235   /* Fetch the list of shared libraries.  */
 236   gdb::optional<gdb::char_vector> library_document
 237     = target_read_stralloc (current_inferior ()->top_target (),
 238                             TARGET_OBJECT_LIBRARIES, NULL);
 239   if (!library_document)
 240     return {};
 241
 242   /* Parse the list.  */
 243   std::vector<lm_info_target_up> library_list
 244     = solib_target_parse_libraries (library_document->data ());
 245
 246   /* Build a struct shobj for each entry on the list.  */
 247   for (lm_info_target_up &info : library_list)
 248     {
 249       shobj *new_solib = new shobj;
 250
 251       /* We don't need a copy of the name in INFO anymore.  */
 252       new_solib->so_name = std::move (info->name);
 253       new_solib->so_original_name = new_solib->so_name;
 254       new_solib->lm_info = std::move (info);
 255
 256       /* Add it to the list.  */
 257       sos.push_back (*new_solib);
 258     }
 259
 260   return sos;
 261 }
 262
 263 static void
 264 solib_target_solib_create_inferior_hook (int from_tty)
 265 {
 266   /* Nothing needed.  */
 267 }
 268
 269 static void
 270 solib_target_relocate_section_addresses (shobj &so, target_section *sec)
 271 {
 272   CORE_ADDR offset;
 273   auto *li = gdb::checked_static_cast<lm_info_target *> (so.lm_info.get ());
 274
 275   /* Build the offset table only once per object file.  We can not do
 276      it any earlier, since we need to open the file first.  */
 277   if (li->offsets.empty ())
 278     {
 279       int num_sections = gdb_bfd_count_sections (so.abfd.get ());
 280
 281       li->offsets.assign (num_sections, 0);
 282
 283       if (!li->section_bases.empty ())
 284         {
 285           int i;
 286           asection *sect;
 287           int num_alloc_sections = 0;
 288
 289           for (i = 0, sect = so.abfd->sections;
 290                sect != NULL;
 291                i++, sect = sect->next)
 292             if ((bfd_section_flags (sect) & SEC_ALLOC))
 293               num_alloc_sections++;
 294
 295           if (num_alloc_sections != li->section_bases.size ())
 296             warning (_("\
 297 Could not relocate shared library \"%s\": wrong number of ALLOC sections"),
 298                      so.so_name.c_str ());
 299           else
 300             {
 301               int bases_index = 0;
 302               int found_range = 0;
 303
 304               so.addr_low = ~(CORE_ADDR) 0;
 305               so.addr_high = 0;
 306               for (i = 0, sect = so.abfd->sections;
 307                    sect != NULL;
 308                    i++, sect = sect->next)
 309                 {
 310                   if (!(bfd_section_flags (sect) & SEC_ALLOC))
 311                     continue;
 312                   if (bfd_section_size (sect) > 0)
 313                     {
 314                       CORE_ADDR low, high;
 315
 316                       low = li->section_bases[i];
 317                       high = low + bfd_section_size (sect) - 1;
 318
 319                       if (low < so.addr_low)
 320                         so.addr_low = low;
 321                       if (high > so.addr_high)
 322                         so.addr_high = high;
 323                       gdb_assert (so.addr_low <= so.addr_high);
 324                       found_range = 1;
 325                     }
 326                   li->offsets[i] = li->section_bases[bases_index];
 327                   bases_index++;
 328                 }
 329               if (!found_range)
 330                 so.addr_low = so.addr_high = 0;
 331               gdb_assert (so.addr_low <= so.addr_high);
 332             }
 333         }
 334       else if (!li->segment_bases.empty ())
 335         {
 336           symfile_segment_data_up data
 337             = get_symfile_segment_data (so.abfd.get ());
 338
 339           if (data == NULL)
 340             warning (_("\
 341 Could not relocate shared library \"%s\": no segments"), so.so_name.c_str ());
 342           else
 343             {
 344               ULONGEST orig_delta;
 345               int i;
 346
 347               if (!symfile_map_offsets_to_segments (so.abfd.get (), data.get (),
 348                                                     li->offsets,
 349                                                     li->segment_bases.size (),
 350                                                     li->segment_bases.data ()))
 351                 warning (_("\
 352 Could not relocate shared library \"%s\": bad offsets"), so.so_name.c_str ());
 353
 354               /* Find the range of addresses to report for this library in
 355                  "info sharedlibrary".  Report any consecutive segments
 356                  which were relocated as a single unit.  */
 357               gdb_assert (li->segment_bases.size () > 0);
 358               orig_delta = li->segment_bases[0] - data->segments[0].base;
 359
 360               for (i = 1; i < data->segments.size (); i++)
 361                 {
 362                   /* If we have run out of offsets, assume all
 363                      remaining segments have the same offset.  */
 364                   if (i >= li->segment_bases.size ())
 365                     continue;
 366
 367                   /* If this segment does not have the same offset, do
 368                      not include it in the library's range.  */
 369                   if (li->segment_bases[i] - data->segments[i].base
 370                       != orig_delta)
 371                     break;
 372                 }
 373
 374               so.addr_low = li->segment_bases[0];
 375               so.addr_high = (data->segments[i - 1].base
 376                                + data->segments[i - 1].size
 377                                + orig_delta);
 378               gdb_assert (so.addr_low <= so.addr_high);
 379             }
 380         }
 381     }
 382
 383   offset = li->offsets[gdb_bfd_section_index (sec->the_bfd_section->owner,
 384                                               sec->the_bfd_section)];
 385   sec->addr += offset;
 386   sec->endaddr += offset;
 387 }
 388
 389 static int
 390 solib_target_open_symbol_file_object (int from_tty)
 391 {
 392   /* We can't locate the main symbol file based on the target's
 393      knowledge; the user has to specify it.  */
 394   return 0;
 395 }
 396
 397 static int
 398 solib_target_in_dynsym_resolve_code (CORE_ADDR pc)
 399 {
 400   /* We don't have a range of addresses for the dynamic linker; there
 401      may not be one in the program's address space.  So only report
 402      PLT entries (which may be import stubs).  */
 403   return in_plt_section (pc);
 404 }
 405
 406 const struct target_so_ops solib_target_so_ops =
 407 {
 408   solib_target_relocate_section_addresses,
 409   nullptr,
 410   nullptr,
 411   solib_target_solib_create_inferior_hook,
 412   solib_target_current_sos,
 413   solib_target_open_symbol_file_object,
 414   solib_target_in_dynsym_resolve_code,
 415   solib_bfd_open,
 416 };