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) 2009-2025 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 "gdbtypes.h"
  22 #include "xml-support.h"
  23 #include "xml-syscall.h"
  24 #include "gdbarch.h"
  25
  26 /* For the struct syscall definition.  */
  27 #include "target.h"
  28
  29 #include "filenames.h"
  30
  31 #ifndef HAVE_LIBEXPAT
  32
  33 /* Dummy functions to indicate that there's no support for fetching
  34    syscalls information.  */
  35
  36 static void
  37 syscall_warn_user (void)
  38 {
  39   static int have_warned = 0;
  40   if (!have_warned)
  41     {
  42       have_warned = 1;
  43       warning (_("Can not parse XML syscalls information; XML support was "
  44                  "disabled at compile time."));
  45     }
  46 }
  47
  48 void
  49 set_xml_syscall_file_name (struct gdbarch *gdbarch, const char *name)
  50 {
  51   return;
  52 }
  53
  54 void
  55 get_syscall_by_number (struct gdbarch *gdbarch,
  56                        int syscall_number, struct syscall *s)
  57 {
  58   syscall_warn_user ();
  59   s->number = syscall_number;
  60   s->name = NULL;
  61 }
  62
  63 bool
  64 get_syscalls_by_name (struct gdbarch *gdbarch, const char *syscall_name,
  65                       std::vector<int> *syscall_numbers)
  66 {
  67   syscall_warn_user ();
  68   return false;
  69 }
  70
  71 const char **
  72 get_syscall_names (struct gdbarch *gdbarch)
  73 {
  74   syscall_warn_user ();
  75   return NULL;
  76 }
  77
  78 bool
  79 get_syscalls_by_group (struct gdbarch *gdbarch, const char *group,
  80                        std::vector<int> *syscall_numbers)
  81 {
  82   syscall_warn_user ();
  83   return false;
  84 }
  85
  86 const char **
  87 get_syscall_group_names (struct gdbarch *gdbarch)
  88 {
  89   syscall_warn_user ();
  90   return NULL;
  91 }
  92
  93 #else /* ! HAVE_LIBEXPAT */
  94
  95 /* Structure which describes a syscall.  */
  96 struct syscall_desc
  97 {
  98   syscall_desc (int number_, std::string name_, std::string alias_)
  99   : number (number_), name (name_), alias (alias_)
 100   {}
 101
 102   /* The syscall number.  */
 103
 104   int number;
 105
 106   /* The syscall name.  */
 107
 108   std::string name;
 109
 110   /* An optional alias.  */
 111
 112   std::string alias;
 113 };
 114
 115 typedef std::unique_ptr<syscall_desc> syscall_desc_up;
 116
 117 /* Structure of a syscall group.  */
 118 struct syscall_group_desc
 119 {
 120   syscall_group_desc (const std::string &name_)
 121   : name (name_)
 122   {}
 123
 124   /* The group name.  */
 125
 126   std::string name;
 127
 128   /* The syscalls that are part of the group.  This is a non-owning
 129      reference.  */
 130
 131   std::vector<syscall_desc *> syscalls;
 132 };
 133
 134 typedef std::unique_ptr<syscall_group_desc> syscall_group_desc_up;
 135
 136 /* Structure that represents syscalls information.  */
 137 struct syscalls_info
 138 {
 139   /* The syscalls.  */
 140
 141   std::vector<syscall_desc_up> syscalls;
 142
 143   /* The syscall groups.  */
 144
 145   std::vector<syscall_group_desc_up> groups;
 146
 147   /* Variable that will hold the last known data-directory.  This is
 148      useful to know whether we should re-read the XML info for the
 149      target.  */
 150
 151   std::string my_gdb_datadir;
 152 };
 153
 154 typedef std::unique_ptr<syscalls_info> syscalls_info_up;
 155
 156 /* Callback data for syscall information parsing.  */
 157 struct syscall_parsing_data
 158 {
 159   /* The syscalls_info we are building.  */
 160
 161   struct syscalls_info *syscalls_info;
 162 };
 163
 164 /* Create a new syscall group.  Return pointer to the
 165    syscall_group_desc structure that represents the new group.  */
 166
 167 static struct syscall_group_desc *
 168 syscall_group_create_syscall_group_desc (struct syscalls_info *syscalls_info,
 169                                          const char *group)
 170 {
 171   syscall_group_desc *groupdesc = new syscall_group_desc (group);
 172
 173   syscalls_info->groups.emplace_back (groupdesc);
 174
 175   return groupdesc;
 176 }
 177
 178 /* Add a syscall to the group.  If group doesn't exist, create it.  */
 179
 180 static void
 181 syscall_group_add_syscall (struct syscalls_info *syscalls_info,
 182                            struct syscall_desc *syscall,
 183                            const char *group)
 184 {
 185   /* Search for an existing group.  */
 186   std::vector<syscall_group_desc_up>::iterator it
 187     = syscalls_info->groups.begin ();
 188
 189   for (; it != syscalls_info->groups.end (); it++)
 190     {
 191       if ((*it)->name == group)
 192         break;
 193     }
 194
 195   syscall_group_desc *groupdesc;
 196
 197   if (it != syscalls_info->groups.end ())
 198     groupdesc = it->get ();
 199   else
 200     {
 201       /* No group was found with this name.  We must create a new
 202          one.  */
 203       groupdesc = syscall_group_create_syscall_group_desc (syscalls_info,
 204                                                            group);
 205     }
 206
 207   groupdesc->syscalls.push_back (syscall);
 208 }
 209
 210 static void
 211 syscall_create_syscall_desc (struct syscalls_info *syscalls_info,
 212                              const char *name, int number, const char *alias,
 213                              char *groups)
 214 {
 215   syscall_desc *sysdesc = new syscall_desc (number, name,
 216                                             alias != NULL ? alias : "");
 217
 218   syscalls_info->syscalls.emplace_back (sysdesc);
 219
 220   /*  Add syscall to its groups.  */
 221   if (groups != NULL)
 222     {
 223       char *saveptr;
 224       for (char *group = strtok_r (groups, ",", &saveptr);
 225            group != NULL;
 226            group = strtok_r (NULL, ",", &saveptr))
 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 (_("Unknown attribute name '%s'."), attr.name);
 257     }
 258
 259   gdb_assert (name);
 260   syscall_create_syscall_desc (data->syscalls_info, name, number, alias,
 261                                groups);
 262 }
 263
 264
 265 /* The elements and attributes of an XML syscall document.  */
 266 static const struct gdb_xml_attribute syscall_attr[] = {
 267   { "number", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
 268   { "name", GDB_XML_AF_NONE, NULL, NULL },
 269   { "alias", GDB_XML_AF_OPTIONAL, NULL, NULL },
 270   { "groups", GDB_XML_AF_OPTIONAL, NULL, NULL },
 271   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 272 };
 273
 274 static const struct gdb_xml_element syscalls_info_children[] = {
 275   { "syscall", syscall_attr, NULL,
 276     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 277     syscall_start_syscall, NULL },
 278   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 279 };
 280
 281 static const struct gdb_xml_element syselements[] = {
 282   { "syscalls_info", NULL, syscalls_info_children,
 283     GDB_XML_EF_NONE, NULL, NULL },
 284   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 285 };
 286
 287 static struct syscalls_info *
 288 syscall_parse_xml (const char *document, xml_fetch_another fetcher)
 289 {
 290   struct syscall_parsing_data data;
 291   syscalls_info_up sysinfo (new syscalls_info ());
 292
 293   data.syscalls_info = sysinfo.get ();
 294
 295   if (gdb_xml_parse_quick (_("syscalls info"), NULL,
 296                            syselements, document, &data) == 0)
 297     {
 298       /* Parsed successfully.  */
 299       return sysinfo.release ();
 300     }
 301   else
 302     {
 303       warning (_("Could not load XML syscalls info; ignoring"));
 304       return NULL;
 305     }
 306 }
 307
 308 /* Function responsible for initializing the information
 309    about the syscalls.  It reads the XML file and fills the
 310    struct syscalls_info with the values.
 311
 312    Returns the struct syscalls_info if the file is valid, NULL otherwise.  */
 313 static struct syscalls_info *
 314 xml_init_syscalls_info (const char *filename)
 315 {
 316   std::optional<gdb::char_vector> full_file
 317     = xml_fetch_content_from_file (filename,
 318                                    const_cast<char *>(gdb_datadir.c_str ()));
 319   if (!full_file)
 320     return NULL;
 321
 322   const std::string dirname = gdb_ldirname (filename);
 323   auto fetch_another = [&dirname] (const char *name)
 324     {
 325       return xml_fetch_content_from_file (name, dirname.c_str ());
 326     };
 327
 328   return syscall_parse_xml (full_file->data (), fetch_another);
 329 }
 330
 331 /* Initializes the syscalls_info structure according to the
 332    architecture.  */
 333 static void
 334 init_syscalls_info (struct gdbarch *gdbarch)
 335 {
 336   struct syscalls_info *syscalls_info = gdbarch_syscalls_info (gdbarch);
 337   const char *xml_syscall_file = gdbarch_xml_syscall_file (gdbarch);
 338
 339   /* Should we re-read the XML info for this target?  */
 340   if (syscalls_info != NULL && !syscalls_info->my_gdb_datadir.empty ()
 341       && filename_cmp (syscalls_info->my_gdb_datadir.c_str (),
 342                        gdb_datadir.c_str ()) != 0)
 343     {
 344       /* The data-directory changed from the last time we used it.
 345          It means that we have to re-read the XML info.  */
 346       delete syscalls_info;
 347       syscalls_info = NULL;
 348       set_gdbarch_syscalls_info (gdbarch, NULL);
 349     }
 350
 351   /* Did we succeed at initializing this?  */
 352   if (syscalls_info != NULL)
 353     return;
 354
 355   syscalls_info = xml_init_syscalls_info (xml_syscall_file);
 356
 357   /* If there was some error reading the XML file, we initialize
 358      gdbarch->syscalls_info anyway, in order to store information
 359      about our attempt.  */
 360   if (syscalls_info == NULL)
 361     syscalls_info = new struct syscalls_info ();
 362
 363   if (syscalls_info->syscalls.empty ())
 364     {
 365       if (xml_syscall_file != NULL)
 366         warning (_("Could not load the syscall XML file `%s/%s'."),
 367                  gdb_datadir.c_str (), xml_syscall_file);
 368       else
 369         warning (_("There is no XML file to open."));
 370
 371       warning (_("GDB will not be able to display "
 372                  "syscall names nor to verify if\n"
 373                  "any provided syscall numbers are valid."));
 374     }
 375
 376   /* Saving the data-directory used to read this XML info.  */
 377   syscalls_info->my_gdb_datadir.assign (gdb_datadir);
 378
 379   set_gdbarch_syscalls_info (gdbarch, syscalls_info);
 380 }
 381
 382 /* Search for a syscall group by its name.  Return syscall_group_desc
 383    structure for the group if found or NULL otherwise.  */
 384
 385 static struct syscall_group_desc *
 386 syscall_group_get_group_by_name (const struct syscalls_info *syscalls_info,
 387                                  const char *group)
 388 {
 389   if (syscalls_info == NULL)
 390     return NULL;
 391
 392   if (group == NULL)
 393     return NULL;
 394
 395   /* Search for existing group.  */
 396   for (const syscall_group_desc_up &groupdesc : syscalls_info->groups)
 397     {
 398       if (groupdesc->name == group)
 399         return groupdesc.get ();
 400     }
 401
 402   return NULL;
 403 }
 404
 405 static bool
 406 xml_get_syscalls_by_name (struct gdbarch *gdbarch, const char *syscall_name,
 407                           std::vector<int> *syscall_numbers)
 408 {
 409   struct syscalls_info *syscalls_info = gdbarch_syscalls_info (gdbarch);
 410
 411   bool found = false;
 412   if (syscalls_info != NULL && syscall_name != NULL && syscall_numbers != NULL)
 413     for (const syscall_desc_up &sysdesc : syscalls_info->syscalls)
 414       if (sysdesc->name == syscall_name || sysdesc->alias == syscall_name)
 415         {
 416           syscall_numbers->push_back (sysdesc->number);
 417           found = true;
 418         }
 419
 420   return found;
 421 }
 422
 423 static const char *
 424 xml_get_syscall_name (struct gdbarch *gdbarch,
 425                       int syscall_number)
 426 {
 427   struct syscalls_info *syscalls_info = gdbarch_syscalls_info (gdbarch);
 428
 429   if (syscalls_info == NULL
 430       || syscall_number < 0)
 431     return NULL;
 432
 433   for (const syscall_desc_up &sysdesc : syscalls_info->syscalls)
 434     if (sysdesc->number == syscall_number)
 435       return sysdesc->name.c_str ();
 436
 437   return NULL;
 438 }
 439
 440 static const char **
 441 xml_list_of_syscalls (struct gdbarch *gdbarch)
 442 {
 443   struct syscalls_info *syscalls_info = gdbarch_syscalls_info (gdbarch);
 444
 445   if (syscalls_info == NULL)
 446     return NULL;
 447
 448   int nsyscalls = syscalls_info->syscalls.size ();
 449   const char **names = XNEWVEC (const char *, nsyscalls + 1);
 450
 451   int i;
 452   for (i = 0; i < syscalls_info->syscalls.size (); i++)
 453     names[i] = syscalls_info->syscalls[i]->name.c_str ();
 454
 455   names[i] = NULL;
 456
 457   return names;
 458 }
 459
 460 /* Iterate over the syscall_group_desc element to return a list of
 461    syscalls that are part of the given group.  If the syscall group
 462    doesn't exist, return false.  */
 463
 464 static bool
 465 xml_list_syscalls_by_group (struct gdbarch *gdbarch, const char *group,
 466                             std::vector<int> *syscalls)
 467 {
 468   struct syscalls_info *syscalls_info = gdbarch_syscalls_info (gdbarch);
 469   struct syscall_group_desc *groupdesc;
 470
 471   if (syscalls_info == NULL || syscalls == NULL)
 472     return false;
 473
 474   groupdesc = syscall_group_get_group_by_name (syscalls_info, group);
 475   if (groupdesc == NULL)
 476     return false;
 477
 478   for (const syscall_desc *sysdesc : groupdesc->syscalls)
 479     syscalls->push_back (sysdesc->number);
 480
 481   return true;
 482 }
 483
 484 /* Return a NULL terminated list of syscall groups or an empty list, if
 485    no syscall group is available.  Return NULL, if there is no syscall
 486    information available.  */
 487
 488 static const char **
 489 xml_list_of_groups (struct gdbarch *gdbarch)
 490 {
 491   struct syscalls_info *syscalls_info = gdbarch_syscalls_info (gdbarch);
 492   const char **names = NULL;
 493   int ngroups;
 494   int i;
 495
 496   if (syscalls_info == NULL)
 497     return NULL;
 498
 499   ngroups = syscalls_info->groups.size ();
 500   names = (const char**) xmalloc ((ngroups + 1) * sizeof (char *));
 501
 502   for (i = 0; i < syscalls_info->groups.size (); i++)
 503     names[i] = syscalls_info->groups[i]->name.c_str ();
 504
 505   names[i] = NULL;
 506
 507   return names;
 508 }
 509
 510 void
 511 set_xml_syscall_file_name (struct gdbarch *gdbarch, const char *name)
 512 {
 513   set_gdbarch_xml_syscall_file (gdbarch, name);
 514 }
 515
 516 void
 517 get_syscall_by_number (struct gdbarch *gdbarch,
 518                        int syscall_number, struct syscall *s)
 519 {
 520   init_syscalls_info (gdbarch);
 521
 522   s->number = syscall_number;
 523   s->name = xml_get_syscall_name (gdbarch, syscall_number);
 524 }
 525
 526 bool
 527 get_syscalls_by_name (struct gdbarch *gdbarch, const char *syscall_name,
 528                       std::vector<int> *syscall_numbers)
 529 {
 530   init_syscalls_info (gdbarch);
 531
 532   return xml_get_syscalls_by_name (gdbarch, syscall_name, syscall_numbers);
 533 }
 534
 535 const char **
 536 get_syscall_names (struct gdbarch *gdbarch)
 537 {
 538   init_syscalls_info (gdbarch);
 539
 540   return xml_list_of_syscalls (gdbarch);
 541 }
 542
 543 /* See comment in xml-syscall.h.  */
 544
 545 bool
 546 get_syscalls_by_group (struct gdbarch *gdbarch, const char *group,
 547                        std::vector<int> *syscall_numbers)
 548 {
 549   init_syscalls_info (gdbarch);
 550
 551   return xml_list_syscalls_by_group (gdbarch, group, syscall_numbers);
 552 }
 553
 554 /* See comment in xml-syscall.h.  */
 555
 556 const char **
 557 get_syscall_group_names (struct gdbarch *gdbarch)
 558 {
 559   init_syscalls_info (gdbarch);
 560
 561   return xml_list_of_groups (gdbarch);
 562 }
 563
 564 #endif /* ! HAVE_LIBEXPAT */