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) 2009-2015 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 void
  65 get_syscall_by_name (struct gdbarch *gdbarch, const char *syscall_name,
  66                      struct syscall *s)
  67 {
  68   syscall_warn_user ();
  69   s->number = UNKNOWN_SYSCALL;
  70   s->name = syscall_name;
  71 }
  72
  73 const char **
  74 get_syscall_names (struct gdbarch *gdbarch)
  75 {
  76   syscall_warn_user ();
  77   return NULL;
  78 }
  79
  80 #else /* ! HAVE_LIBEXPAT */
  81
  82 /* Structure which describes a syscall.  */
  83 typedef struct syscall_desc
  84 {
  85   /* The syscall number.  */
  86
  87   int number;
  88
  89   /* The syscall name.  */
  90
  91   char *name;
  92 } *syscall_desc_p;
  93 DEF_VEC_P(syscall_desc_p);
  94
  95 /* Structure that represents syscalls information.  */
  96 struct syscalls_info
  97 {
  98   /* The syscalls.  */
  99
 100   VEC(syscall_desc_p) *syscalls;
 101
 102   /* Variable that will hold the last known data-directory.  This is
 103      useful to know whether we should re-read the XML info for the
 104      target.  */
 105
 106   char *my_gdb_datadir;
 107 };
 108
 109 /* Callback data for syscall information parsing.  */
 110 struct syscall_parsing_data
 111 {
 112   /* The syscalls_info we are building.  */
 113
 114   struct syscalls_info *syscalls_info;
 115 };
 116
 117 static struct syscalls_info *
 118 allocate_syscalls_info (void)
 119 {
 120   return XCNEW (struct syscalls_info);
 121 }
 122
 123 static void
 124 syscalls_info_free_syscalls_desc (struct syscall_desc *sd)
 125 {
 126   xfree (sd->name);
 127 }
 128
 129 static void
 130 free_syscalls_info (void *arg)
 131 {
 132   struct syscalls_info *syscalls_info = arg;
 133   struct syscall_desc *sysdesc;
 134   int i;
 135
 136   xfree (syscalls_info->my_gdb_datadir);
 137
 138   if (syscalls_info->syscalls != NULL)
 139     {
 140       for (i = 0;
 141            VEC_iterate (syscall_desc_p, syscalls_info->syscalls, i, sysdesc);
 142            i++)
 143         syscalls_info_free_syscalls_desc (sysdesc);
 144       VEC_free (syscall_desc_p, syscalls_info->syscalls);
 145     }
 146
 147   xfree (syscalls_info);
 148 }
 149
 150 static struct cleanup *
 151 make_cleanup_free_syscalls_info (struct syscalls_info *syscalls_info)
 152 {
 153   return make_cleanup (free_syscalls_info, syscalls_info);
 154 }
 155
 156 static void
 157 syscall_create_syscall_desc (struct syscalls_info *syscalls_info,
 158                              const char *name, int number)
 159 {
 160   struct syscall_desc *sysdesc = XCNEW (struct syscall_desc);
 161
 162   sysdesc->name = xstrdup (name);
 163   sysdesc->number = number;
 164
 165   VEC_safe_push (syscall_desc_p, syscalls_info->syscalls, sysdesc);
 166 }
 167
 168 /* Handle the start of a <syscall> element.  */
 169 static void
 170 syscall_start_syscall (struct gdb_xml_parser *parser,
 171                        const struct gdb_xml_element *element,
 172                        void *user_data, VEC(gdb_xml_value_s) *attributes)
 173 {
 174   struct syscall_parsing_data *data = user_data;
 175   struct gdb_xml_value *attrs = VEC_address (gdb_xml_value_s, attributes);
 176   int len, i;
 177   /* syscall info.  */
 178   char *name = NULL;
 179   int number = 0;
 180
 181   len = VEC_length (gdb_xml_value_s, attributes);
 182
 183   for (i = 0; i < len; i++)
 184     {
 185       if (strcmp (attrs[i].name, "name") == 0)
 186         name = attrs[i].value;
 187       else if (strcmp (attrs[i].name, "number") == 0)
 188         number = * (ULONGEST *) attrs[i].value;
 189       else
 190         internal_error (__FILE__, __LINE__,
 191                         _("Unknown attribute name '%s'."), attrs[i].name);
 192     }
 193
 194   gdb_assert (name);
 195   syscall_create_syscall_desc (data->syscalls_info, name, number);
 196 }
 197
 198
 199 /* The elements and attributes of an XML syscall document.  */
 200 static const struct gdb_xml_attribute syscall_attr[] = {
 201   { "number", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
 202   { "name", GDB_XML_AF_NONE, NULL, NULL },
 203   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 204 };
 205
 206 static const struct gdb_xml_element syscalls_info_children[] = {
 207   { "syscall", syscall_attr, NULL,
 208     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 209     syscall_start_syscall, NULL },
 210   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 211 };
 212
 213 static const struct gdb_xml_element syselements[] = {
 214   { "syscalls_info", NULL, syscalls_info_children,
 215     GDB_XML_EF_NONE, NULL, NULL },
 216   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 217 };
 218
 219 static struct syscalls_info *
 220 syscall_parse_xml (const char *document, xml_fetch_another fetcher,
 221                    void *fetcher_baton)
 222 {
 223   struct cleanup *result_cleanup;
 224   struct syscall_parsing_data data;
 225
 226   data.syscalls_info = allocate_syscalls_info ();
 227   result_cleanup = make_cleanup_free_syscalls_info (data.syscalls_info);
 228
 229   if (gdb_xml_parse_quick (_("syscalls info"), NULL,
 230                            syselements, document, &data) == 0)
 231     {
 232       /* Parsed successfully.  */
 233       discard_cleanups (result_cleanup);
 234       return data.syscalls_info;
 235     }
 236   else
 237     {
 238       warning (_("Could not load XML syscalls info; ignoring"));
 239       do_cleanups (result_cleanup);
 240       return NULL;
 241     }
 242 }
 243
 244 /* Function responsible for initializing the information
 245    about the syscalls.  It reads the XML file and fills the
 246    struct syscalls_info with the values.
 247
 248    Returns the struct syscalls_info if the file is valid, NULL otherwise.  */
 249 static struct syscalls_info *
 250 xml_init_syscalls_info (const char *filename)
 251 {
 252   char *full_file;
 253   char *dirname;
 254   struct syscalls_info *syscalls_info;
 255   struct cleanup *back_to;
 256
 257   full_file = xml_fetch_content_from_file (filename, gdb_datadir);
 258   if (full_file == NULL)
 259     return NULL;
 260
 261   back_to = make_cleanup (xfree, full_file);
 262
 263   dirname = ldirname (filename);
 264   if (dirname != NULL)
 265     make_cleanup (xfree, dirname);
 266
 267   syscalls_info = syscall_parse_xml (full_file,
 268                                      xml_fetch_content_from_file, dirname);
 269   do_cleanups (back_to);
 270
 271   return syscalls_info;
 272 }
 273
 274 /* Initializes the syscalls_info structure according to the
 275    architecture.  */
 276 static void
 277 init_syscalls_info (struct gdbarch *gdbarch)
 278 {
 279   struct syscalls_info *syscalls_info = gdbarch_syscalls_info (gdbarch);
 280   const char *xml_syscall_file = gdbarch_xml_syscall_file (gdbarch);
 281
 282   /* Should we re-read the XML info for this target?  */
 283   if (syscalls_info != NULL && syscalls_info->my_gdb_datadir != NULL
 284       && filename_cmp (syscalls_info->my_gdb_datadir, gdb_datadir) != 0)
 285     {
 286       /* The data-directory changed from the last time we used it.
 287          It means that we have to re-read the XML info.  */
 288       free_syscalls_info (syscalls_info);
 289       syscalls_info = NULL;
 290       set_gdbarch_syscalls_info (gdbarch, NULL);
 291     }
 292
 293   /* Did we succeed at initializing this?  */
 294   if (syscalls_info != NULL)
 295     return;
 296
 297   syscalls_info = xml_init_syscalls_info (xml_syscall_file);
 298
 299   /* If there was some error reading the XML file, we initialize
 300      gdbarch->syscalls_info anyway, in order to store information
 301      about our attempt.  */
 302   if (syscalls_info == NULL)
 303     syscalls_info = allocate_syscalls_info ();
 304
 305   if (syscalls_info->syscalls == NULL)
 306     {
 307       if (xml_syscall_file != NULL)
 308         warning (_("Could not load the syscall XML file `%s/%s'."),
 309                  gdb_datadir, xml_syscall_file);
 310       else
 311         warning (_("There is no XML file to open."));
 312
 313       warning (_("GDB will not be able to display "
 314                  "syscall names nor to verify if\n"
 315                  "any provided syscall numbers are valid."));
 316     }
 317
 318   /* Saving the data-directory used to read this XML info.  */
 319   syscalls_info->my_gdb_datadir = xstrdup (gdb_datadir);
 320
 321   set_gdbarch_syscalls_info (gdbarch, syscalls_info);
 322 }
 323
 324 static int
 325 xml_get_syscall_number (struct gdbarch *gdbarch,
 326                         const char *syscall_name)
 327 {
 328   struct syscalls_info *syscalls_info = gdbarch_syscalls_info (gdbarch);
 329   struct syscall_desc *sysdesc;
 330   int i;
 331
 332   if (syscalls_info == NULL
 333       || syscall_name == NULL)
 334     return UNKNOWN_SYSCALL;
 335
 336   for (i = 0;
 337        VEC_iterate(syscall_desc_p, syscalls_info->syscalls, i, sysdesc);
 338        i++)
 339     if (strcmp (sysdesc->name, syscall_name) == 0)
 340       return sysdesc->number;
 341
 342   return UNKNOWN_SYSCALL;
 343 }
 344
 345 static const char *
 346 xml_get_syscall_name (struct gdbarch *gdbarch,
 347                       int syscall_number)
 348 {
 349   struct syscalls_info *syscalls_info = gdbarch_syscalls_info (gdbarch);
 350   struct syscall_desc *sysdesc;
 351   int i;
 352
 353   if (syscalls_info == NULL
 354       || syscall_number < 0)
 355     return NULL;
 356
 357   for (i = 0;
 358        VEC_iterate(syscall_desc_p, syscalls_info->syscalls, i, sysdesc);
 359        i++)
 360     if (sysdesc->number == syscall_number)
 361       return sysdesc->name;
 362
 363   return NULL;
 364 }
 365
 366 static const char **
 367 xml_list_of_syscalls (struct gdbarch *gdbarch)
 368 {
 369   struct syscalls_info *syscalls_info = gdbarch_syscalls_info (gdbarch);
 370   struct syscall_desc *sysdesc;
 371   const char **names = NULL;
 372   int nsyscalls;
 373   int i;
 374
 375   if (syscalls_info == NULL)
 376     return NULL;
 377
 378   nsyscalls = VEC_length (syscall_desc_p, syscalls_info->syscalls);
 379   names = xmalloc ((nsyscalls + 1) * sizeof (char *));
 380
 381   for (i = 0;
 382        VEC_iterate (syscall_desc_p, syscalls_info->syscalls, i, sysdesc);
 383        i++)
 384     names[i] = sysdesc->name;
 385
 386   names[i] = NULL;
 387
 388   return names;
 389 }
 390
 391 void
 392 set_xml_syscall_file_name (struct gdbarch *gdbarch, const char *name)
 393 {
 394   set_gdbarch_xml_syscall_file (gdbarch, name);
 395 }
 396
 397 void
 398 get_syscall_by_number (struct gdbarch *gdbarch,
 399                        int syscall_number, struct syscall *s)
 400 {
 401   init_syscalls_info (gdbarch);
 402
 403   s->number = syscall_number;
 404   s->name = xml_get_syscall_name (gdbarch, syscall_number);
 405 }
 406
 407 void
 408 get_syscall_by_name (struct gdbarch *gdbarch,
 409                      const char *syscall_name, struct syscall *s)
 410 {
 411   init_syscalls_info (gdbarch);
 412
 413   s->number = xml_get_syscall_number (gdbarch, syscall_name);
 414   s->name = syscall_name;
 415 }
 416
 417 const char **
 418 get_syscall_names (struct gdbarch *gdbarch)
 419 {
 420   init_syscalls_info (gdbarch);
 421
 422   return xml_list_of_syscalls (gdbarch);
 423 }
 424
 425 #endif /* ! HAVE_LIBEXPAT */