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) 2009-2014 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 (const struct gdbarch *gdbarch,
  51                            const char *name)
  52 {
  53   return;
  54 }
  55
  56 void
  57 get_syscall_by_number (const struct gdbarch *gdbarch,
  58                        int syscall_number, struct syscall *s)
  59 {
  60   syscall_warn_user ();
  61   s->number = syscall_number;
  62   s->name = NULL;
  63 }
  64
  65 void
  66 get_syscall_by_name (const struct gdbarch *gdbarch,
  67                      const char *syscall_name, struct syscall *s)
  68 {
  69   syscall_warn_user ();
  70   s->number = UNKNOWN_SYSCALL;
  71   s->name = syscall_name;
  72 }
  73
  74 const char **
  75 get_syscall_names (const struct gdbarch *gdbarch)
  76 {
  77   syscall_warn_user ();
  78   return NULL;
  79 }
  80
  81 #else /* ! HAVE_LIBEXPAT */
  82
  83 /* Structure which describes a syscall.  */
  84 typedef struct syscall_desc
  85 {
  86   /* The syscall number.  */
  87
  88   int number;
  89
  90   /* The syscall name.  */
  91
  92   char *name;
  93 } *syscall_desc_p;
  94 DEF_VEC_P(syscall_desc_p);
  95
  96 /* Structure that represents syscalls information.  */
  97 struct syscalls_info
  98 {
  99   /* The syscalls.  */
 100
 101   VEC(syscall_desc_p) *syscalls;
 102
 103   /* Variable that will hold the last known data-directory.  This is
 104      useful to know whether we should re-read the XML info for the
 105      target.  */
 106
 107   char *my_gdb_datadir;
 108 };
 109
 110 /* Callback data for syscall information parsing.  */
 111 struct syscall_parsing_data
 112 {
 113   /* The syscalls_info we are building.  */
 114
 115   struct syscalls_info *syscalls_info;
 116 };
 117
 118 static struct syscalls_info *
 119 allocate_syscalls_info (void)
 120 {
 121   return XCNEW (struct syscalls_info);
 122 }
 123
 124 static void
 125 syscalls_info_free_syscalls_desc (struct syscall_desc *sd)
 126 {
 127   xfree (sd->name);
 128 }
 129
 130 static void
 131 free_syscalls_info (void *arg)
 132 {
 133   struct syscalls_info *syscalls_info = arg;
 134   struct syscall_desc *sysdesc;
 135   int i;
 136
 137   xfree (syscalls_info->my_gdb_datadir);
 138
 139   if (syscalls_info->syscalls != NULL)
 140     {
 141       for (i = 0;
 142            VEC_iterate (syscall_desc_p, syscalls_info->syscalls, i, sysdesc);
 143            i++)
 144         syscalls_info_free_syscalls_desc (sysdesc);
 145       VEC_free (syscall_desc_p, syscalls_info->syscalls);
 146     }
 147
 148   xfree (syscalls_info);
 149 }
 150
 151 static struct cleanup *
 152 make_cleanup_free_syscalls_info (struct syscalls_info *syscalls_info)
 153 {
 154   return make_cleanup (free_syscalls_info, syscalls_info);
 155 }
 156
 157 static void
 158 syscall_create_syscall_desc (struct syscalls_info *syscalls_info,
 159                              const char *name, int number)
 160 {
 161   struct syscall_desc *sysdesc = XCNEW (struct syscall_desc);
 162
 163   sysdesc->name = xstrdup (name);
 164   sysdesc->number = number;
 165
 166   VEC_safe_push (syscall_desc_p, syscalls_info->syscalls, sysdesc);
 167 }
 168
 169 /* Handle the start of a <syscall> element.  */
 170 static void
 171 syscall_start_syscall (struct gdb_xml_parser *parser,
 172                        const struct gdb_xml_element *element,
 173                        void *user_data, VEC(gdb_xml_value_s) *attributes)
 174 {
 175   struct syscall_parsing_data *data = user_data;
 176   struct gdb_xml_value *attrs = VEC_address (gdb_xml_value_s, attributes);
 177   int len, i;
 178   /* syscall info.  */
 179   char *name = NULL;
 180   int number = 0;
 181
 182   len = VEC_length (gdb_xml_value_s, attributes);
 183
 184   for (i = 0; i < len; i++)
 185     {
 186       if (strcmp (attrs[i].name, "name") == 0)
 187         name = attrs[i].value;
 188       else if (strcmp (attrs[i].name, "number") == 0)
 189         number = * (ULONGEST *) attrs[i].value;
 190       else
 191         internal_error (__FILE__, __LINE__,
 192                         _("Unknown attribute name '%s'."), attrs[i].name);
 193     }
 194
 195   gdb_assert (name);
 196   syscall_create_syscall_desc (data->syscalls_info, name, number);
 197 }
 198
 199
 200 /* The elements and attributes of an XML syscall document.  */
 201 static const struct gdb_xml_attribute syscall_attr[] = {
 202   { "number", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
 203   { "name", GDB_XML_AF_NONE, NULL, NULL },
 204   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 205 };
 206
 207 static const struct gdb_xml_element syscalls_info_children[] = {
 208   { "syscall", syscall_attr, NULL,
 209     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 210     syscall_start_syscall, NULL },
 211   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 212 };
 213
 214 static const struct gdb_xml_element syselements[] = {
 215   { "syscalls_info", NULL, syscalls_info_children,
 216     GDB_XML_EF_NONE, NULL, NULL },
 217   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 218 };
 219
 220 static struct syscalls_info *
 221 syscall_parse_xml (const char *document, xml_fetch_another fetcher,
 222                    void *fetcher_baton)
 223 {
 224   struct cleanup *result_cleanup;
 225   struct syscall_parsing_data data;
 226
 227   data.syscalls_info = allocate_syscalls_info ();
 228   result_cleanup = make_cleanup_free_syscalls_info (data.syscalls_info);
 229
 230   if (gdb_xml_parse_quick (_("syscalls info"), NULL,
 231                            syselements, document, &data) == 0)
 232     {
 233       /* Parsed successfully.  */
 234       discard_cleanups (result_cleanup);
 235       return data.syscalls_info;
 236     }
 237   else
 238     {
 239       warning (_("Could not load XML syscalls info; ignoring"));
 240       do_cleanups (result_cleanup);
 241       return NULL;
 242     }
 243 }
 244
 245 /* Function responsible for initializing the information
 246    about the syscalls.  It reads the XML file and fills the
 247    struct syscalls_info with the values.
 248
 249    Returns the struct syscalls_info if the file is valid, NULL otherwise.  */
 250 static struct syscalls_info *
 251 xml_init_syscalls_info (const char *filename)
 252 {
 253   char *full_file;
 254   char *dirname;
 255   struct syscalls_info *syscalls_info;
 256   struct cleanup *back_to;
 257
 258   full_file = xml_fetch_content_from_file (filename, gdb_datadir);
 259   if (full_file == NULL)
 260     return NULL;
 261
 262   back_to = make_cleanup (xfree, full_file);
 263
 264   dirname = ldirname (filename);
 265   if (dirname != NULL)
 266     make_cleanup (xfree, dirname);
 267
 268   syscalls_info = syscall_parse_xml (full_file,
 269                                      xml_fetch_content_from_file, dirname);
 270   do_cleanups (back_to);
 271
 272   return syscalls_info;
 273 }
 274
 275 /* Initializes the syscalls_info structure according to the
 276    architecture.  */
 277 static void
 278 init_syscalls_info (struct gdbarch *gdbarch)
 279 {
 280   struct syscalls_info *syscalls_info = gdbarch_syscalls_info (gdbarch);
 281   const char *xml_syscall_file = gdbarch_xml_syscall_file (gdbarch);
 282
 283   /* Should we re-read the XML info for this target?  */
 284   if (syscalls_info != NULL && syscalls_info->my_gdb_datadir != NULL
 285       && filename_cmp (syscalls_info->my_gdb_datadir, gdb_datadir) != 0)
 286     {
 287       /* The data-directory changed from the last time we used it.
 288          It means that we have to re-read the XML info.  */
 289       free_syscalls_info (syscalls_info);
 290       syscalls_info = NULL;
 291       set_gdbarch_syscalls_info (gdbarch, NULL);
 292     }
 293
 294   /* Did we succeed at initializing this?  */
 295   if (syscalls_info != NULL)
 296     return;
 297
 298   syscalls_info = xml_init_syscalls_info (xml_syscall_file);
 299
 300   /* If there was some error reading the XML file, we initialize
 301      gdbarch->syscalls_info anyway, in order to store information
 302      about our attempt.  */
 303   if (syscalls_info == NULL)
 304     syscalls_info = allocate_syscalls_info ();
 305
 306   if (syscalls_info->syscalls == NULL)
 307     {
 308       if (xml_syscall_file != NULL)
 309         warning (_("Could not load the syscall XML file `%s/%s'."),
 310                  gdb_datadir, xml_syscall_file);
 311       else
 312         warning (_("There is no XML file to open."));
 313
 314       warning (_("GDB will not be able to display "
 315                  "syscall names nor to verify if\n"
 316                  "any provided syscall numbers are valid."));
 317     }
 318
 319   /* Saving the data-directory used to read this XML info.  */
 320   syscalls_info->my_gdb_datadir = xstrdup (gdb_datadir);
 321
 322   set_gdbarch_syscalls_info (gdbarch, syscalls_info);
 323 }
 324
 325 static int
 326 xml_get_syscall_number (struct gdbarch *gdbarch,
 327                         const char *syscall_name)
 328 {
 329   struct syscalls_info *syscalls_info = gdbarch_syscalls_info (gdbarch);
 330   struct syscall_desc *sysdesc;
 331   int i;
 332
 333   if (syscalls_info == NULL
 334       || syscall_name == NULL)
 335     return UNKNOWN_SYSCALL;
 336
 337   for (i = 0;
 338        VEC_iterate(syscall_desc_p, syscalls_info->syscalls, i, sysdesc);
 339        i++)
 340     if (strcmp (sysdesc->name, syscall_name) == 0)
 341       return sysdesc->number;
 342
 343   return UNKNOWN_SYSCALL;
 344 }
 345
 346 static const char *
 347 xml_get_syscall_name (struct gdbarch *gdbarch,
 348                       int syscall_number)
 349 {
 350   struct syscalls_info *syscalls_info = gdbarch_syscalls_info (gdbarch);
 351   struct syscall_desc *sysdesc;
 352   int i;
 353
 354   if (syscalls_info == NULL
 355       || syscall_number < 0)
 356     return NULL;
 357
 358   for (i = 0;
 359        VEC_iterate(syscall_desc_p, syscalls_info->syscalls, i, sysdesc);
 360        i++)
 361     if (sysdesc->number == syscall_number)
 362       return sysdesc->name;
 363
 364   return NULL;
 365 }
 366
 367 static const char **
 368 xml_list_of_syscalls (struct gdbarch *gdbarch)
 369 {
 370   struct syscalls_info *syscalls_info = gdbarch_syscalls_info (gdbarch);
 371   struct syscall_desc *sysdesc;
 372   const char **names = NULL;
 373   int nsyscalls;
 374   int i;
 375
 376   if (syscalls_info == NULL)
 377     return NULL;
 378
 379   nsyscalls = VEC_length (syscall_desc_p, syscalls_info->syscalls);
 380   names = xmalloc ((nsyscalls + 1) * sizeof (char *));
 381
 382   for (i = 0;
 383        VEC_iterate (syscall_desc_p, syscalls_info->syscalls, i, sysdesc);
 384        i++)
 385     names[i] = sysdesc->name;
 386
 387   names[i] = NULL;
 388
 389   return names;
 390 }
 391
 392 void
 393 set_xml_syscall_file_name (struct gdbarch *gdbarch, const char *name)
 394 {
 395   set_gdbarch_xml_syscall_file (gdbarch, name);
 396 }
 397
 398 void
 399 get_syscall_by_number (struct gdbarch *gdbarch,
 400                        int syscall_number, struct syscall *s)
 401 {
 402   init_syscalls_info (gdbarch);
 403
 404   s->number = syscall_number;
 405   s->name = xml_get_syscall_name (gdbarch, syscall_number);
 406 }
 407
 408 void
 409 get_syscall_by_name (struct gdbarch *gdbarch,
 410                      const char *syscall_name, struct syscall *s)
 411 {
 412   init_syscalls_info (gdbarch);
 413
 414   s->number = xml_get_syscall_number (gdbarch, syscall_name);
 415   s->name = syscall_name;
 416 }
 417
 418 const char **
 419 get_syscall_names (struct gdbarch *gdbarch)
 420 {
 421   init_syscalls_info (gdbarch);
 422
 423   return xml_list_of_syscalls (gdbarch);
 424 }
 425
 426 #endif /* ! HAVE_LIBEXPAT */