gdb/solib-target.c

   1 /* Definitions for targets which report shared library events.
   2
   3    Copyright (C) 2007-2024 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 "objfiles.h"
  21 #include "solist.h"
  22 #include "symtab.h"
  23 #include "symfile.h"
  24 #include "target.h"
  25 #include "solib-target.h"
  26 #include <vector>
  27 #include "inferior.h"
  28
  29 /* Private data for each loaded library.  */
  30 struct lm_info_target final : public lm_info
  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 using lm_info_target_up = std::unique_ptr<lm_info_target>;
  53
  54 #if !defined(HAVE_LIBEXPAT)
  55
  56 static std::vector<lm_info_target_up>
  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 {};
  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   auto *list = (std::vector<lm_info_target_up> *) 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   auto *list = (std::vector<lm_info_target_up> *) 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   auto *list = (std::vector<lm_info_target_up> *) 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   auto *list = (std::vector<lm_info_target_up> *) 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 std::vector<lm_info_target_up>
 213 solib_target_parse_libraries (const char *library)
 214 {
 215   std::vector<lm_info_target_up> 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 owning_intrusive_list<solib>
 230 solib_target_current_sos (void)
 231 {
 232   owning_intrusive_list<solib> sos;
 233
 234   /* Fetch the list of shared libraries.  */
 235   std::optional<gdb::char_vector> library_document
 236     = target_read_stralloc (current_inferior ()->top_target (),
 237                             TARGET_OBJECT_LIBRARIES, NULL);
 238   if (!library_document)
 239     return {};
 240
 241   /* Parse the list.  */
 242   std::vector<lm_info_target_up> library_list
 243     = solib_target_parse_libraries (library_document->data ());
 244
 245   /* Build a struct solib for each entry on the list.  */
 246   for (lm_info_target_up &info : library_list)
 247     {
 248       auto &new_solib = sos.emplace_back ();
 249
 250       /* We don't need a copy of the name in INFO anymore.  */
 251       new_solib.so_name = std::move (info->name);
 252       new_solib.so_original_name = new_solib.so_name;
 253       new_solib.lm_info = std::move (info);
 254     }
 255
 256   return sos;
 257 }
 258
 259 static void
 260 solib_target_solib_create_inferior_hook (int from_tty)
 261 {
 262   /* Nothing needed.  */
 263 }
 264
 265 static void
 266 solib_target_relocate_section_addresses (solib &so, target_section *sec)
 267 {
 268   CORE_ADDR offset;
 269   auto *li = gdb::checked_static_cast<lm_info_target *> (so.lm_info.get ());
 270
 271   /* Build the offset table only once per object file.  We can not do
 272      it any earlier, since we need to open the file first.  */
 273   if (li->offsets.empty ())
 274     {
 275       int num_sections = gdb_bfd_count_sections (so.abfd.get ());
 276
 277       li->offsets.assign (num_sections, 0);
 278
 279       if (!li->section_bases.empty ())
 280         {
 281           int i;
 282           asection *sect;
 283           int num_alloc_sections = 0;
 284
 285           for (i = 0, sect = so.abfd->sections;
 286                sect != NULL;
 287                i++, sect = sect->next)
 288             if ((bfd_section_flags (sect) & SEC_ALLOC))
 289               num_alloc_sections++;
 290
 291           if (num_alloc_sections != li->section_bases.size ())
 292             warning (_("\
 293 Could not relocate shared library \"%s\": wrong number of ALLOC sections"),
 294                      so.so_name.c_str ());
 295           else
 296             {
 297               int bases_index = 0;
 298               int found_range = 0;
 299
 300               so.addr_low = ~(CORE_ADDR) 0;
 301               so.addr_high = 0;
 302               for (i = 0, sect = so.abfd->sections;
 303                    sect != NULL;
 304                    i++, sect = sect->next)
 305                 {
 306                   if (!(bfd_section_flags (sect) & SEC_ALLOC))
 307                     continue;
 308                   if (bfd_section_size (sect) > 0)
 309                     {
 310                       CORE_ADDR low, high;
 311
 312                       low = li->section_bases[i];
 313                       high = low + bfd_section_size (sect) - 1;
 314
 315                       if (low < so.addr_low)
 316                         so.addr_low = low;
 317                       if (high > so.addr_high)
 318                         so.addr_high = high;
 319                       gdb_assert (so.addr_low <= so.addr_high);
 320                       found_range = 1;
 321                     }
 322                   li->offsets[i] = li->section_bases[bases_index];
 323                   bases_index++;
 324                 }
 325               if (!found_range)
 326                 so.addr_low = so.addr_high = 0;
 327               gdb_assert (so.addr_low <= so.addr_high);
 328             }
 329         }
 330       else if (!li->segment_bases.empty ())
 331         {
 332           symfile_segment_data_up data
 333             = get_symfile_segment_data (so.abfd.get ());
 334
 335           if (data == NULL)
 336             warning (_("\
 337 Could not relocate shared library \"%s\": no segments"), so.so_name.c_str ());
 338           else
 339             {
 340               ULONGEST orig_delta;
 341               int i;
 342
 343               if (!symfile_map_offsets_to_segments (so.abfd.get (), data.get (),
 344                                                     li->offsets,
 345                                                     li->segment_bases.size (),
 346                                                     li->segment_bases.data ()))
 347                 warning (_("\
 348 Could not relocate shared library \"%s\": bad offsets"), so.so_name.c_str ());
 349
 350               /* Find the range of addresses to report for this library in
 351                  "info sharedlibrary".  Report any consecutive segments
 352                  which were relocated as a single unit.  */
 353               gdb_assert (li->segment_bases.size () > 0);
 354               orig_delta = li->segment_bases[0] - data->segments[0].base;
 355
 356               for (i = 1; i < data->segments.size (); i++)
 357                 {
 358                   /* If we have run out of offsets, assume all
 359                      remaining segments have the same offset.  */
 360                   if (i >= li->segment_bases.size ())
 361                     continue;
 362
 363                   /* If this segment does not have the same offset, do
 364                      not include it in the library's range.  */
 365                   if (li->segment_bases[i] - data->segments[i].base
 366                       != orig_delta)
 367                     break;
 368                 }
 369
 370               so.addr_low = li->segment_bases[0];
 371               so.addr_high = (data->segments[i - 1].base
 372                                + data->segments[i - 1].size
 373                                + orig_delta);
 374               gdb_assert (so.addr_low <= so.addr_high);
 375             }
 376         }
 377     }
 378
 379   offset = li->offsets[gdb_bfd_section_index (sec->the_bfd_section->owner,
 380                                               sec->the_bfd_section)];
 381   sec->addr += offset;
 382   sec->endaddr += offset;
 383 }
 384
 385 static int
 386 solib_target_open_symbol_file_object (int from_tty)
 387 {
 388   /* We can't locate the main symbol file based on the target's
 389      knowledge; the user has to specify it.  */
 390   return 0;
 391 }
 392
 393 static int
 394 solib_target_in_dynsym_resolve_code (CORE_ADDR pc)
 395 {
 396   /* We don't have a range of addresses for the dynamic linker; there
 397      may not be one in the program's address space.  So only report
 398      PLT entries (which may be import stubs).  */
 399   return in_plt_section (pc);
 400 }
 401
 402 const solib_ops solib_target_so_ops =
 403 {
 404   solib_target_relocate_section_addresses,
 405   nullptr,
 406   nullptr,
 407   solib_target_solib_create_inferior_hook,
 408   solib_target_current_sos,
 409   solib_target_open_symbol_file_object,
 410   solib_target_in_dynsym_resolve_code,
 411   solib_bfd_open,
 412   nullptr,
 413   nullptr,
 414   nullptr,
 415   nullptr,
 416   default_find_solib_addr,
 417 };