gdb/xml-syscall.c

   1 /* Functions that provide the mechanism to parse a syscall XML file
   2    and get its values.
   3
   4    Copyright (C) 2009-2020 Free Software Foundation, Inc.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 #include "defs.h"
  22 #include "gdbtypes.h"
  23 #include "xml-support.h"
  24 #include "xml-syscall.h"
  25 #include "gdbarch.h"
  26
  27 /* For the struct syscall definition.  */
  28 #include "target.h"
  29
  30 #include "filenames.h"
  31
  32 #ifndef HAVE_LIBEXPAT
  33
  34 /* Dummy functions to indicate that there's no support for fetching
  35    syscalls information.  */
  36
  37 static void
  38 syscall_warn_user (void)
  39 {
  40   static int have_warned = 0;
  41   if (!have_warned)
  42     {
  43       have_warned = 1;
  44       warning (_("Can not parse XML syscalls information; XML support was "
  45                  "disabled at compile time."));
  46     }
  47 }
  48
  49 void
  50 set_xml_syscall_file_name (struct gdbarch *gdbarch, const char *name)
  51 {
  52   return;
  53 }
  54
  55 void
  56 get_syscall_by_number (struct gdbarch *gdbarch,
  57                        int syscall_number, struct syscall *s)
  58 {
  59   syscall_warn_user ();
  60   s->number = syscall_number;
  61   s->name = NULL;
  62 }
  63
  64 bool
  65 get_syscalls_by_name (struct gdbarch *gdbarch, const char *syscall_name,
  66                       std::vector<int> *syscall_numbers)
  67 {
  68   syscall_warn_user ();
  69   return false;
  70 }
  71
  72 const char **
  73 get_syscall_names (struct gdbarch *gdbarch)
  74 {
  75   syscall_warn_user ();
  76   return NULL;
  77 }
  78
  79 bool
  80 get_syscalls_by_group (struct gdbarch *gdbarch, const char *group,
  81                        std::vector<int> *syscall_numbers)
  82 {
  83   syscall_warn_user ();
  84   return false;
  85 }
  86
  87 const char **
  88 get_syscall_group_names (struct gdbarch *gdbarch)
  89 {
  90   syscall_warn_user ();
  91   return NULL;
  92 }
  93
  94 #else /* ! HAVE_LIBEXPAT */
  95
  96 /* Structure which describes a syscall.  */
  97 struct syscall_desc
  98 {
  99   syscall_desc (int number_, std::string name_, std::string alias_)
 100   : number (number_), name (name_), alias (alias_)
 101   {}
 102
 103   /* The syscall number.  */
 104
 105   int number;
 106
 107   /* The syscall name.  */
 108
 109   std::string name;
 110
 111   /* An optional alias.  */
 112
 113   std::string alias;
 114 };
 115
 116 typedef std::unique_ptr<syscall_desc> syscall_desc_up;
 117
 118 /* Structure of a syscall group.  */
 119 struct syscall_group_desc
 120 {
 121   syscall_group_desc (const std::string &name_)
 122   : name (name_)
 123   {}
 124
 125   /* The group name.  */
 126
 127   std::string name;
 128
 129   /* The syscalls that are part of the group.  This is a non-owning
 130      reference.  */
 131
 132   std::vector<syscall_desc *> syscalls;
 133 };
 134
 135 typedef std::unique_ptr<syscall_group_desc> syscall_group_desc_up;
 136
 137 /* Structure that represents syscalls information.  */
 138 struct syscalls_info
 139 {
 140   /* The syscalls.  */
 141
 142   std::vector<syscall_desc_up> syscalls;
 143
 144   /* The syscall groups.  */
 145
 146   std::vector<syscall_group_desc_up> groups;
 147
 148   /* Variable that will hold the last known data-directory.  This is
 149      useful to know whether we should re-read the XML info for the
 150      target.  */
 151
 152   std::string my_gdb_datadir;
 153 };
 154
 155 typedef std::unique_ptr<syscalls_info> syscalls_info_up;
 156
 157 /* Callback data for syscall information parsing.  */
 158 struct syscall_parsing_data
 159 {
 160   /* The syscalls_info we are building.  */
 161
 162   struct syscalls_info *syscalls_info;
 163 };
 164
 165 /* Create a new syscall group.  Return pointer to the
 166    syscall_group_desc structure that represents the new group.  */
 167
 168 static struct syscall_group_desc *
 169 syscall_group_create_syscall_group_desc (struct syscalls_info *syscalls_info,
 170                                          const char *group)
 171 {
 172   syscall_group_desc *groupdesc = new syscall_group_desc (group);
 173
 174   syscalls_info->groups.emplace_back (groupdesc);
 175
 176   return groupdesc;
 177 }
 178
 179 /* Add a syscall to the group.  If group doesn't exist, create it.  */
 180
 181 static void
 182 syscall_group_add_syscall (struct syscalls_info *syscalls_info,
 183                            struct syscall_desc *syscall,
 184                            const char *group)
 185 {
 186   /* Search for an existing group.  */
 187   std::vector<syscall_group_desc_up>::iterator it
 188     = syscalls_info->groups.begin ();
 189
 190   for (; it != syscalls_info->groups.end (); it++)
 191     {
 192       if ((*it)->name == group)
 193         break;
 194     }
 195
 196   syscall_group_desc *groupdesc;
 197
 198   if (it != syscalls_info->groups.end ())
 199     groupdesc = it->get ();
 200   else
 201     {
 202       /* No group was found with this name.  We must create a new
 203          one.  */
 204       groupdesc = syscall_group_create_syscall_group_desc (syscalls_info,
 205                                                            group);
 206     }
 207
 208   groupdesc->syscalls.push_back (syscall);
 209 }
 210
 211 static void
 212 syscall_create_syscall_desc (struct syscalls_info *syscalls_info,
 213                              const char *name, int number, const char *alias,
 214                              char *groups)
 215 {
 216   syscall_desc *sysdesc = new syscall_desc (number, name,
 217                                             alias != NULL ? alias : "");
 218
 219   syscalls_info->syscalls.emplace_back (sysdesc);
 220
 221   /*  Add syscall to its groups.  */
 222   if (groups != NULL)
 223     {
 224       char *saveptr;
 225       for (char *group = strtok_r (groups, ",", &saveptr);
 226            group != NULL;
 227            group = strtok_r (NULL, ",", &saveptr))
 228         syscall_group_add_syscall (syscalls_info, sysdesc, group);
 229     }
 230 }
 231
 232 /* Handle the start of a <syscall> element.  */
 233 static void
 234 syscall_start_syscall (struct gdb_xml_parser *parser,
 235                        const struct gdb_xml_element *element,
 236                        void *user_data,
 237                        std::vector<gdb_xml_value> &attributes)
 238 {
 239   struct syscall_parsing_data *data = (struct syscall_parsing_data *) user_data;
 240   /* syscall info.  */
 241   char *name = NULL;
 242   int number = 0;
 243   char *alias = NULL;
 244   char *groups = NULL;
 245
 246   for (const gdb_xml_value &attr : attributes)
 247     {
 248       if (strcmp (attr.name, "name") == 0)
 249         name = (char *) attr.value.get ();
 250       else if (strcmp (attr.name, "number") == 0)
 251         number = * (ULONGEST *) attr.value.get ();
 252       else if (strcmp (attr.name, "alias") == 0)
 253         alias = (char *) attr.value.get ();
 254       else if (strcmp (attr.name, "groups") == 0)
 255         groups = (char *) attr.value.get ();
 256       else
 257         internal_error (__FILE__, __LINE__,
 258                         _("Unknown attribute name '%s'."), attr.name);
 259     }
 260
 261   gdb_assert (name);
 262   syscall_create_syscall_desc (data->syscalls_info, name, number, alias,
 263                                groups);
 264 }
 265
 266
 267 /* The elements and attributes of an XML syscall document.  */
 268 static const struct gdb_xml_attribute syscall_attr[] = {
 269   { "number", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
 270   { "name", GDB_XML_AF_NONE, NULL, NULL },
 271   { "alias", GDB_XML_AF_OPTIONAL, NULL, NULL },
 272   { "groups", GDB_XML_AF_OPTIONAL, NULL, NULL },
 273   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 274 };
 275
 276 static const struct gdb_xml_element syscalls_info_children[] = {
 277   { "syscall", syscall_attr, NULL,
 278     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 279     syscall_start_syscall, NULL },
 280   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 281 };
 282
 283 static const struct gdb_xml_element syselements[] = {
 284   { "syscalls_info", NULL, syscalls_info_children,
 285     GDB_XML_EF_NONE, NULL, NULL },
 286   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 287 };
 288
 289 static struct syscalls_info *
 290 syscall_parse_xml (const char *document, xml_fetch_another fetcher,
 291                    void *fetcher_baton)
 292 {
 293   struct syscall_parsing_data data;
 294   syscalls_info_up sysinfo (new syscalls_info ());
 295
 296   data.syscalls_info = sysinfo.get ();
 297
 298   if (gdb_xml_parse_quick (_("syscalls info"), NULL,
 299                            syselements, document, &data) == 0)
 300     {
 301       /* Parsed successfully.  */
 302       return sysinfo.release ();
 303     }
 304   else
 305     {
 306       warning (_("Could not load XML syscalls info; ignoring"));
 307       return NULL;
 308     }
 309 }
 310
 311 /* Function responsible for initializing the information
 312    about the syscalls.  It reads the XML file and fills the
 313    struct syscalls_info with the values.
 314
 315    Returns the struct syscalls_info if the file is valid, NULL otherwise.  */
 316 static struct syscalls_info *
 317 xml_init_syscalls_info (const char *filename)
 318 {
 319   gdb::optional<gdb::char_vector> full_file
 320     = xml_fetch_content_from_file (filename,
 321                                    const_cast<char *>(gdb_datadir.c_str ()));
 322   if (!full_file)
 323     return NULL;
 324
 325   return syscall_parse_xml (full_file->data (),
 326                             xml_fetch_content_from_file,
 327                             (void *) ldirname (filename).c_str ());
 328 }
 329
 330 /* Initializes the syscalls_info structure according to the
 331    architecture.  */
 332 static void
 333 init_syscalls_info (struct gdbarch *gdbarch)
 334 {
 335   struct syscalls_info *syscalls_info = gdbarch_syscalls_info (gdbarch);
 336   const char *xml_syscall_file = gdbarch_xml_syscall_file (gdbarch);
 337
 338   /* Should we re-read the XML info for this target?  */
 339   if (syscalls_info != NULL && !syscalls_info->my_gdb_datadir.empty ()
 340       && filename_cmp (syscalls_info->my_gdb_datadir.c_str (),
 341                        gdb_datadir.c_str ()) != 0)
 342     {
 343       /* The data-directory changed from the last time we used it.
 344          It means that we have to re-read the XML info.  */
 345       delete syscalls_info;
 346       syscalls_info = NULL;
 347       set_gdbarch_syscalls_info (gdbarch, NULL);
 348     }
 349
 350   /* Did we succeed at initializing this?  */
 351   if (syscalls_info != NULL)
 352     return;
 353
 354   syscalls_info = xml_init_syscalls_info (xml_syscall_file);
 355
 356   /* If there was some error reading the XML file, we initialize
 357      gdbarch->syscalls_info anyway, in order to store information
 358      about our attempt.  */
 359   if (syscalls_info == NULL)
 360     syscalls_info = new struct syscalls_info ();
 361
 362   if (syscalls_info->syscalls.empty ())
 363     {
 364       if (xml_syscall_file != NULL)
 365         warning (_("Could not load the syscall XML file `%s/%s'."),
 366                  gdb_datadir.c_str (), xml_syscall_file);
 367       else
 368         warning (_("There is no XML file to open."));
 369
 370       warning (_("GDB will not be able to display "
 371                  "syscall names nor to verify if\n"
 372                  "any provided syscall numbers are valid."));
 373     }
 374
 375   /* Saving the data-directory used to read this XML info.  */
 376   syscalls_info->my_gdb_datadir.assign (gdb_datadir);
 377
 378   set_gdbarch_syscalls_info (gdbarch, syscalls_info);
 379 }
 380
 381 /* Search for a syscall group by its name.  Return syscall_group_desc
 382    structure for the group if found or NULL otherwise.  */
 383
 384 static struct syscall_group_desc *
 385 syscall_group_get_group_by_name (const struct syscalls_info *syscalls_info,
 386                                  const char *group)
 387 {
 388   if (syscalls_info == NULL)
 389     return NULL;
 390
 391   if (group == NULL)
 392     return NULL;
 393
 394   /* Search for existing group.  */
 395   for (const syscall_group_desc_up &groupdesc : syscalls_info->groups)
 396     {
 397       if (groupdesc->name == group)
 398         return groupdesc.get ();
 399     }
 400
 401   return NULL;
 402 }
 403
 404 static bool
 405 xml_get_syscalls_by_name (struct gdbarch *gdbarch, const char *syscall_name,
 406                           std::vector<int> *syscall_numbers)
 407 {
 408   struct syscalls_info *syscalls_info = gdbarch_syscalls_info (gdbarch);
 409
 410   bool found = false;
 411   if (syscalls_info != NULL && syscall_name != NULL && syscall_numbers != NULL)
 412     for (const syscall_desc_up &sysdesc : syscalls_info->syscalls)
 413       if (sysdesc->name == syscall_name || sysdesc->alias == syscall_name)
 414         {
 415           syscall_numbers->push_back (sysdesc->number);
 416           found = true;
 417         }
 418
 419   return found;
 420 }
 421
 422 static const char *
 423 xml_get_syscall_name (struct gdbarch *gdbarch,
 424                       int syscall_number)
 425 {
 426   struct syscalls_info *syscalls_info = gdbarch_syscalls_info (gdbarch);
 427
 428   if (syscalls_info == NULL
 429       || syscall_number < 0)
 430     return NULL;
 431
 432   for (const syscall_desc_up &sysdesc : syscalls_info->syscalls)
 433     if (sysdesc->number == syscall_number)
 434       return sysdesc->name.c_str ();
 435
 436   return NULL;
 437 }
 438
 439 static const char **
 440 xml_list_of_syscalls (struct gdbarch *gdbarch)
 441 {
 442   struct syscalls_info *syscalls_info = gdbarch_syscalls_info (gdbarch);
 443
 444   if (syscalls_info == NULL)
 445     return NULL;
 446
 447   int nsyscalls = syscalls_info->syscalls.size ();
 448   const char **names = XNEWVEC (const char *, nsyscalls + 1);
 449
 450   int i;
 451   for (i = 0; i < syscalls_info->syscalls.size (); i++)
 452     names[i] = syscalls_info->syscalls[i]->name.c_str ();
 453
 454   names[i] = NULL;
 455
 456   return names;
 457 }
 458
 459 /* Iterate over the syscall_group_desc element to return a list of
 460    syscalls that are part of the given group.  If the syscall group
 461    doesn't exist, return false.  */
 462
 463 static bool
 464 xml_list_syscalls_by_group (struct gdbarch *gdbarch, const char *group,
 465                             std::vector<int> *syscalls)
 466 {
 467   struct syscalls_info *syscalls_info = gdbarch_syscalls_info (gdbarch);
 468   struct syscall_group_desc *groupdesc;
 469
 470   if (syscalls_info == NULL || syscalls == NULL)
 471     return false;
 472
 473   groupdesc = syscall_group_get_group_by_name (syscalls_info, group);
 474   if (groupdesc == NULL)
 475     return false;
 476
 477   for (const syscall_desc *sysdesc : groupdesc->syscalls)
 478     syscalls->push_back (sysdesc->number);
 479
 480   return true;
 481 }
 482
 483 /* Return a NULL terminated list of syscall groups or an empty list, if
 484    no syscall group is available.  Return NULL, if there is no syscall
 485    information available.  */
 486
 487 static const char **
 488 xml_list_of_groups (struct gdbarch *gdbarch)
 489 {
 490   struct syscalls_info *syscalls_info = gdbarch_syscalls_info (gdbarch);
 491   const char **names = NULL;
 492   int ngroups;
 493   int i;
 494
 495   if (syscalls_info == NULL)
 496     return NULL;
 497
 498   ngroups = syscalls_info->groups.size ();
 499   names = (const char**) xmalloc ((ngroups + 1) * sizeof (char *));
 500
 501   for (i = 0; i < syscalls_info->groups.size (); i++)
 502     names[i] = syscalls_info->groups[i]->name.c_str ();
 503
 504   names[i] = NULL;
 505
 506   return names;
 507 }
 508
 509 void
 510 set_xml_syscall_file_name (struct gdbarch *gdbarch, const char *name)
 511 {
 512   set_gdbarch_xml_syscall_file (gdbarch, name);
 513 }
 514
 515 void
 516 get_syscall_by_number (struct gdbarch *gdbarch,
 517                        int syscall_number, struct syscall *s)
 518 {
 519   init_syscalls_info (gdbarch);
 520
 521   s->number = syscall_number;
 522   s->name = xml_get_syscall_name (gdbarch, syscall_number);
 523 }
 524
 525 bool
 526 get_syscalls_by_name (struct gdbarch *gdbarch, const char *syscall_name,
 527                       std::vector<int> *syscall_numbers)
 528 {
 529   init_syscalls_info (gdbarch);
 530
 531   return xml_get_syscalls_by_name (gdbarch, syscall_name, syscall_numbers);
 532 }
 533
 534 const char **
 535 get_syscall_names (struct gdbarch *gdbarch)
 536 {
 537   init_syscalls_info (gdbarch);
 538
 539   return xml_list_of_syscalls (gdbarch);
 540 }
 541
 542 /* See comment in xml-syscall.h.  */
 543
 544 bool
 545 get_syscalls_by_group (struct gdbarch *gdbarch, const char *group,
 546                        std::vector<int> *syscall_numbers)
 547 {
 548   init_syscalls_info (gdbarch);
 549
 550   return xml_list_syscalls_by_group (gdbarch, group, syscall_numbers);
 551 }
 552
 553 /* See comment in xml-syscall.h.  */
 554
 555 const char **
 556 get_syscall_group_names (struct gdbarch *gdbarch)
 557 {
 558   init_syscalls_info (gdbarch);
 559
 560   return xml_list_of_groups (gdbarch);
 561 }
 562
 563 #endif /* ! HAVE_LIBEXPAT */