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) 2009-2018 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       for (char *group = strtok (groups, ",");
 225            group != NULL;
 226            group = strtok (NULL, ","))
 227         syscall_group_add_syscall (syscalls_info, sysdesc, group);
 228     }
 229 }
 230
 231 /* Handle the start of a <syscall> element.  */
 232 static void
 233 syscall_start_syscall (struct gdb_xml_parser *parser,
 234                        const struct gdb_xml_element *element,
 235                        void *user_data,
 236                        std::vector<gdb_xml_value> &attributes)
 237 {
 238   struct syscall_parsing_data *data = (struct syscall_parsing_data *) user_data;
 239   /* syscall info.  */
 240   char *name = NULL;
 241   int number = 0;
 242   char *alias = NULL;
 243   char *groups = NULL;
 244
 245   for (const gdb_xml_value &attr : attributes)
 246     {
 247       if (strcmp (attr.name, "name") == 0)
 248         name = (char *) attr.value.get ();
 249       else if (strcmp (attr.name, "number") == 0)
 250         number = * (ULONGEST *) attr.value.get ();
 251       else if (strcmp (attr.name, "alias") == 0)
 252         alias = (char *) attr.value.get ();
 253       else if (strcmp (attr.name, "groups") == 0)
 254         groups = (char *) attr.value.get ();
 255       else
 256         internal_error (__FILE__, __LINE__,
 257                         _("Unknown attribute name '%s'."), attr.name);
 258     }
 259
 260   gdb_assert (name);
 261   syscall_create_syscall_desc (data->syscalls_info, name, number, alias,
 262                                groups);
 263 }
 264
 265
 266 /* The elements and attributes of an XML syscall document.  */
 267 static const struct gdb_xml_attribute syscall_attr[] = {
 268   { "number", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
 269   { "name", GDB_XML_AF_NONE, NULL, NULL },
 270   { "alias", GDB_XML_AF_OPTIONAL, NULL, NULL },
 271   { "groups", GDB_XML_AF_OPTIONAL, NULL, NULL },
 272   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 273 };
 274
 275 static const struct gdb_xml_element syscalls_info_children[] = {
 276   { "syscall", syscall_attr, NULL,
 277     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 278     syscall_start_syscall, NULL },
 279   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 280 };
 281
 282 static const struct gdb_xml_element syselements[] = {
 283   { "syscalls_info", NULL, syscalls_info_children,
 284     GDB_XML_EF_NONE, NULL, NULL },
 285   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 286 };
 287
 288 static struct syscalls_info *
 289 syscall_parse_xml (const char *document, xml_fetch_another fetcher,
 290                    void *fetcher_baton)
 291 {
 292   struct syscall_parsing_data data;
 293   syscalls_info_up sysinfo (new syscalls_info ());
 294
 295   data.syscalls_info = sysinfo.get ();
 296
 297   if (gdb_xml_parse_quick (_("syscalls info"), NULL,
 298                            syselements, document, &data) == 0)
 299     {
 300       /* Parsed successfully.  */
 301       return sysinfo.release ();
 302     }
 303   else
 304     {
 305       warning (_("Could not load XML syscalls info; ignoring"));
 306       return NULL;
 307     }
 308 }
 309
 310 /* Function responsible for initializing the information
 311    about the syscalls.  It reads the XML file and fills the
 312    struct syscalls_info with the values.
 313
 314    Returns the struct syscalls_info if the file is valid, NULL otherwise.  */
 315 static struct syscalls_info *
 316 xml_init_syscalls_info (const char *filename)
 317 {
 318   gdb::optional<gdb::char_vector> full_file
 319     = xml_fetch_content_from_file (filename, gdb_datadir);
 320   if (!full_file)
 321     return NULL;
 322
 323   return syscall_parse_xml (full_file->data (),
 324                             xml_fetch_content_from_file,
 325                             (void *) ldirname (filename).c_str ());
 326 }
 327
 328 /* Initializes the syscalls_info structure according to the
 329    architecture.  */
 330 static void
 331 init_syscalls_info (struct gdbarch *gdbarch)
 332 {
 333   struct syscalls_info *syscalls_info = gdbarch_syscalls_info (gdbarch);
 334   const char *xml_syscall_file = gdbarch_xml_syscall_file (gdbarch);
 335
 336   /* Should we re-read the XML info for this target?  */
 337   if (syscalls_info != NULL && !syscalls_info->my_gdb_datadir.empty ()
 338       && filename_cmp (syscalls_info->my_gdb_datadir.c_str (),
 339                        gdb_datadir) != 0)
 340     {
 341       /* The data-directory changed from the last time we used it.
 342          It means that we have to re-read the XML info.  */
 343       delete syscalls_info;
 344       syscalls_info = NULL;
 345       set_gdbarch_syscalls_info (gdbarch, NULL);
 346     }
 347
 348   /* Did we succeed at initializing this?  */
 349   if (syscalls_info != NULL)
 350     return;
 351
 352   syscalls_info = xml_init_syscalls_info (xml_syscall_file);
 353
 354   /* If there was some error reading the XML file, we initialize
 355      gdbarch->syscalls_info anyway, in order to store information
 356      about our attempt.  */
 357   if (syscalls_info == NULL)
 358     syscalls_info = new struct syscalls_info ();
 359
 360   if (syscalls_info->syscalls.empty ())
 361     {
 362       if (xml_syscall_file != NULL)
 363         warning (_("Could not load the syscall XML file `%s/%s'."),
 364                  gdb_datadir, xml_syscall_file);
 365       else
 366         warning (_("There is no XML file to open."));
 367
 368       warning (_("GDB will not be able to display "
 369                  "syscall names nor to verify if\n"
 370                  "any provided syscall numbers are valid."));
 371     }
 372
 373   /* Saving the data-directory used to read this XML info.  */
 374   syscalls_info->my_gdb_datadir.assign (gdb_datadir);
 375
 376   set_gdbarch_syscalls_info (gdbarch, syscalls_info);
 377 }
 378
 379 /* Search for a syscall group by its name.  Return syscall_group_desc
 380    structure for the group if found or NULL otherwise.  */
 381
 382 static struct syscall_group_desc *
 383 syscall_group_get_group_by_name (const struct syscalls_info *syscalls_info,
 384                                  const char *group)
 385 {
 386   if (syscalls_info == NULL)
 387     return NULL;
 388
 389   if (group == NULL)
 390     return NULL;
 391
 392   /* Search for existing group.  */
 393   for (const syscall_group_desc_up &groupdesc : syscalls_info->groups)
 394     {
 395       if (groupdesc->name == group)
 396         return groupdesc.get ();
 397     }
 398
 399   return NULL;
 400 }
 401
 402 static bool
 403 xml_get_syscalls_by_name (struct gdbarch *gdbarch, const char *syscall_name,
 404                           std::vector<int> *syscall_numbers)
 405 {
 406   struct syscalls_info *syscalls_info = gdbarch_syscalls_info (gdbarch);
 407
 408   bool found = false;
 409   if (syscalls_info != NULL && syscall_name != NULL && syscall_numbers != NULL)
 410     for (const syscall_desc_up &sysdesc : syscalls_info->syscalls)
 411       if (sysdesc->name == syscall_name || sysdesc->alias == syscall_name)
 412         {
 413           syscall_numbers->push_back (sysdesc->number);
 414           found = true;
 415         }
 416
 417   return found;
 418 }
 419
 420 static const char *
 421 xml_get_syscall_name (struct gdbarch *gdbarch,
 422                       int syscall_number)
 423 {
 424   struct syscalls_info *syscalls_info = gdbarch_syscalls_info (gdbarch);
 425
 426   if (syscalls_info == NULL
 427       || syscall_number < 0)
 428     return NULL;
 429
 430   for (const syscall_desc_up &sysdesc : syscalls_info->syscalls)
 431     if (sysdesc->number == syscall_number)
 432       return sysdesc->name.c_str ();
 433
 434   return NULL;
 435 }
 436
 437 static const char **
 438 xml_list_of_syscalls (struct gdbarch *gdbarch)
 439 {
 440   struct syscalls_info *syscalls_info = gdbarch_syscalls_info (gdbarch);
 441
 442   if (syscalls_info == NULL)
 443     return NULL;
 444
 445   int nsyscalls = syscalls_info->syscalls.size ();
 446   const char **names = XNEWVEC (const char *, nsyscalls + 1);
 447
 448   int i;
 449   for (i = 0; i < syscalls_info->syscalls.size (); i++)
 450     names[i] = syscalls_info->syscalls[i]->name.c_str ();
 451
 452   names[i] = NULL;
 453
 454   return names;
 455 }
 456
 457 /* Iterate over the syscall_group_desc element to return a list of
 458    syscalls that are part of the given group.  If the syscall group
 459    doesn't exist, return false.  */
 460
 461 static bool
 462 xml_list_syscalls_by_group (struct gdbarch *gdbarch, const char *group,
 463                             std::vector<int> *syscalls)
 464 {
 465   struct syscalls_info *syscalls_info = gdbarch_syscalls_info (gdbarch);
 466   struct syscall_group_desc *groupdesc;
 467
 468   if (syscalls_info == NULL || syscalls == NULL)
 469     return false;
 470
 471   groupdesc = syscall_group_get_group_by_name (syscalls_info, group);
 472   if (groupdesc == NULL)
 473     return false;
 474
 475   for (const struct syscall_desc *sysdesc : groupdesc->syscalls)
 476     syscalls->push_back (sysdesc->number);
 477
 478   return true;
 479 }
 480
 481 /* Return a NULL terminated list of syscall groups or an empty list, if
 482    no syscall group is available.  Return NULL, if there is no syscall
 483    information available.  */
 484
 485 static const char **
 486 xml_list_of_groups (struct gdbarch *gdbarch)
 487 {
 488   struct syscalls_info *syscalls_info = gdbarch_syscalls_info (gdbarch);
 489   const char **names = NULL;
 490   int ngroups;
 491   int i;
 492
 493   if (syscalls_info == NULL)
 494     return NULL;
 495
 496   ngroups = syscalls_info->groups.size ();
 497   names = (const char**) xmalloc ((ngroups + 1) * sizeof (char *));
 498
 499   for (i = 0; i < syscalls_info->groups.size (); i++)
 500     names[i] = syscalls_info->groups[i]->name.c_str ();
 501
 502   names[i] = NULL;
 503
 504   return names;
 505 }
 506
 507 void
 508 set_xml_syscall_file_name (struct gdbarch *gdbarch, const char *name)
 509 {
 510   set_gdbarch_xml_syscall_file (gdbarch, name);
 511 }
 512
 513 void
 514 get_syscall_by_number (struct gdbarch *gdbarch,
 515                        int syscall_number, struct syscall *s)
 516 {
 517   init_syscalls_info (gdbarch);
 518
 519   s->number = syscall_number;
 520   s->name = xml_get_syscall_name (gdbarch, syscall_number);
 521 }
 522
 523 bool
 524 get_syscalls_by_name (struct gdbarch *gdbarch, const char *syscall_name,
 525                       std::vector<int> *syscall_numbers)
 526 {
 527   init_syscalls_info (gdbarch);
 528
 529   return xml_get_syscalls_by_name (gdbarch, syscall_name, syscall_numbers);
 530 }
 531
 532 const char **
 533 get_syscall_names (struct gdbarch *gdbarch)
 534 {
 535   init_syscalls_info (gdbarch);
 536
 537   return xml_list_of_syscalls (gdbarch);
 538 }
 539
 540 /* See comment in xml-syscall.h.  */
 541
 542 bool
 543 get_syscalls_by_group (struct gdbarch *gdbarch, const char *group,
 544                        std::vector<int> *syscall_numbers)
 545 {
 546   init_syscalls_info (gdbarch);
 547
 548   return xml_list_syscalls_by_group (gdbarch, group, syscall_numbers);
 549 }
 550
 551 /* See comment in xml-syscall.h.  */
 552
 553 const char **
 554 get_syscall_group_names (struct gdbarch *gdbarch)
 555 {
 556   init_syscalls_info (gdbarch);
 557
 558   return xml_list_of_groups (gdbarch);
 559 }
 560
 561 #endif /* ! HAVE_LIBEXPAT */