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, 2010 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
  26 /* For the struct syscall definition.  */
  27 #include "target.h"
  28
  29 #include "filenames.h"
  30
  31 #include "gdb_assert.h"
  32
  33 #ifndef HAVE_LIBEXPAT
  34
  35 /* Dummy functions to indicate that there's no support for fetching
  36    syscalls information.  */
  37
  38 static void
  39 syscall_warn_user (void)
  40 {
  41   static int have_warned = 0;
  42   if (!have_warned)
  43     {
  44       have_warned = 1;
  45       warning (_("Can not parse XML syscalls information; XML support was "
  46                  "disabled at compile time."));
  47     }
  48 }
  49
  50 void
  51 set_xml_syscall_file_name (const char *name)
  52 {
  53   return;
  54 }
  55
  56 void
  57 get_syscall_by_number (int syscall_number,
  58                        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 char *syscall_name,
  67                      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 (void)
  76 {
  77   syscall_warn_user ();
  78   return NULL;
  79 }
  80
  81 #else /* ! HAVE_LIBEXPAT */
  82
  83 /* Variable that will hold the last known data-directory.  This is useful to
  84    know whether we should re-read the XML info for the target.  */
  85 static char *my_gdb_datadir = NULL;
  86
  87 /* Structure which describes a syscall.  */
  88 typedef struct syscall_desc
  89 {
  90   /* The syscall number.  */
  91
  92   int number;
  93
  94   /* The syscall name.  */
  95
  96   char *name;
  97 } *syscall_desc_p;
  98 DEF_VEC_P(syscall_desc_p);
  99
 100 /* Structure that represents syscalls information.  */
 101 struct syscalls_info
 102 {
 103   /* The syscalls.  */
 104
 105   VEC(syscall_desc_p) *syscalls;
 106 };
 107
 108 /* Callback data for syscall information parsing.  */
 109 struct syscall_parsing_data
 110 {
 111   /* The syscalls_info we are building.  */
 112
 113   struct syscalls_info *sysinfo;
 114 };
 115
 116 /* Structure used to store information about the available syscalls in
 117    the system.  */
 118 static const struct syscalls_info *sysinfo = NULL;
 119
 120 /* A flag to tell if we already initialized the structure above.  */
 121 static int have_initialized_sysinfo = 0;
 122
 123 /* The filename of the syscall's XML.  */
 124 static const char *xml_syscall_file = NULL;
 125
 126 static struct syscalls_info *
 127 allocate_syscalls_info (void)
 128 {
 129   return XZALLOC (struct syscalls_info);
 130 }
 131
 132 static void
 133 sysinfo_free_syscalls_desc (struct syscall_desc *sd)
 134 {
 135   xfree (sd->name);
 136 }
 137
 138 static void
 139 free_syscalls_info (void *arg)
 140 {
 141   struct syscalls_info *sysinfo = arg;
 142   struct syscall_desc *sysdesc;
 143   int i;
 144
 145   for (i = 0;
 146        VEC_iterate (syscall_desc_p, sysinfo->syscalls, i, sysdesc);
 147        i++)
 148     sysinfo_free_syscalls_desc (sysdesc);
 149   VEC_free (syscall_desc_p, sysinfo->syscalls);
 150
 151   xfree (sysinfo);
 152 }
 153
 154 struct cleanup *
 155 make_cleanup_free_syscalls_info (struct syscalls_info *sysinfo)
 156 {
 157   return make_cleanup (free_syscalls_info, sysinfo);
 158 }
 159
 160 static void
 161 syscall_create_syscall_desc (struct syscalls_info *sysinfo,
 162                              const char *name, int number)
 163 {
 164   struct syscall_desc *sysdesc = XZALLOC (struct syscall_desc);
 165
 166   sysdesc->name = xstrdup (name);
 167   sysdesc->number = number;
 168
 169   VEC_safe_push (syscall_desc_p, sysinfo->syscalls, sysdesc);
 170 }
 171
 172 /* Handle the start of a <syscall> element.  */
 173 static void
 174 syscall_start_syscall (struct gdb_xml_parser *parser,
 175                        const struct gdb_xml_element *element,
 176                        void *user_data, VEC(gdb_xml_value_s) *attributes)
 177 {
 178   struct syscall_parsing_data *data = user_data;
 179   struct gdb_xml_value *attrs = VEC_address (gdb_xml_value_s, attributes);
 180   int len, i;
 181   /* syscall info.  */
 182   char *name = NULL;
 183   int number = 0;
 184
 185   len = VEC_length (gdb_xml_value_s, attributes);
 186
 187   for (i = 0; i < len; i++)
 188     {
 189       if (strcmp (attrs[i].name, "name") == 0)
 190         name = attrs[i].value;
 191       else if (strcmp (attrs[i].name, "number") == 0)
 192         number = * (ULONGEST *) attrs[i].value;
 193       else
 194         internal_error (__FILE__, __LINE__,
 195                         _("Unknown attribute name '%s'."), attrs[i].name);
 196     }
 197
 198   syscall_create_syscall_desc (data->sysinfo, name, number);
 199 }
 200
 201
 202 /* The elements and attributes of an XML syscall document.  */
 203 static const struct gdb_xml_attribute syscall_attr[] = {
 204   { "number", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
 205   { "name", GDB_XML_AF_NONE, NULL, NULL },
 206   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 207 };
 208
 209 static const struct gdb_xml_element syscalls_info_children[] = {
 210   { "syscall", syscall_attr, NULL,
 211     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 212     syscall_start_syscall, NULL },
 213   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 214 };
 215
 216 static const struct gdb_xml_element syselements[] = {
 217   { "syscalls_info", NULL, syscalls_info_children,
 218     GDB_XML_EF_NONE, NULL, NULL },
 219   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 220 };
 221
 222 static struct syscalls_info *
 223 syscall_parse_xml (const char *document, xml_fetch_another fetcher,
 224                    void *fetcher_baton)
 225 {
 226   struct cleanup *result_cleanup;
 227   struct gdb_xml_parser *parser;
 228   struct syscall_parsing_data data;
 229
 230   parser = gdb_xml_create_parser_and_cleanup (_("syscalls info"),
 231                                               syselements, &data);
 232
 233   memset (&data, 0, sizeof (struct syscall_parsing_data));
 234   data.sysinfo = allocate_syscalls_info ();
 235   result_cleanup = make_cleanup_free_syscalls_info (data.sysinfo);
 236
 237   if (gdb_xml_parse (parser, document) == 0)
 238     {
 239       /* Parsed successfully.  */
 240       discard_cleanups (result_cleanup);
 241       return data.sysinfo;
 242     }
 243   else
 244     {
 245       warning (_("Could not load XML syscalls info; ignoring"));
 246       do_cleanups (result_cleanup);
 247       return NULL;
 248     }
 249 }
 250
 251 /* Function responsible for initializing the information
 252    about the syscalls.  It reads the XML file and fills the
 253    struct syscalls_info with the values.
 254
 255    Returns the struct syscalls_info if the file is valid, NULL otherwise.  */
 256 static const struct syscalls_info *
 257 xml_init_syscalls_info (const char *filename)
 258 {
 259   char *full_file;
 260   char *dirname;
 261   struct syscalls_info *sysinfo;
 262   struct cleanup *back_to;
 263
 264   full_file = xml_fetch_content_from_file (filename, gdb_datadir);
 265   if (full_file == NULL)
 266     return NULL;
 267
 268   back_to = make_cleanup (xfree, full_file);
 269
 270   dirname = ldirname (filename);
 271   if (dirname != NULL)
 272     make_cleanup (xfree, dirname);
 273
 274   sysinfo = syscall_parse_xml (full_file, xml_fetch_content_from_file, dirname);
 275   do_cleanups (back_to);
 276
 277   return sysinfo;
 278 }
 279
 280 /* Initializes the syscalls_info structure according to the
 281    architecture.  */
 282 static void
 283 init_sysinfo (void)
 284 {
 285   /* Should we re-read the XML info for this target?  */
 286   if (my_gdb_datadir && strcmp (my_gdb_datadir, gdb_datadir) != 0)
 287     {
 288       /* The data-directory changed from the last time we used it.
 289          It means that we have to re-read the XML info.  */
 290       have_initialized_sysinfo = 0;
 291       xfree (my_gdb_datadir);
 292       my_gdb_datadir = NULL;
 293       if (sysinfo)
 294         free_syscalls_info ((void *) sysinfo);
 295     }
 296
 297   /* Did we already try to initialize the structure?  */
 298   if (have_initialized_sysinfo)
 299     return;
 300
 301   sysinfo = xml_init_syscalls_info (xml_syscall_file);
 302
 303   have_initialized_sysinfo = 1;
 304
 305   if (sysinfo == NULL)
 306     {
 307       if (xml_syscall_file)
 308         warning (_("\
 309 Could not load the syscall XML file `%s/%s'."),
 310                  gdb_datadir, xml_syscall_file);
 311       else
 312         warning (_("\
 313 There is no XML file to open."));
 314
 315       warning (_("\
 316 GDB will not be able to display syscall names nor to verify if\n\
 317 any provided syscall numbers are valid."));
 318     }
 319
 320   /* Saving the data-directory used to read this XML info.  */
 321   my_gdb_datadir = xstrdup (gdb_datadir);
 322 }
 323
 324 static int
 325 xml_get_syscall_number (const struct syscalls_info *sysinfo,
 326                         const char *syscall_name)
 327 {
 328   struct syscall_desc *sysdesc;
 329   int i;
 330
 331   if (sysinfo == NULL
 332       || syscall_name == NULL)
 333     return UNKNOWN_SYSCALL;
 334
 335   for (i = 0;
 336        VEC_iterate(syscall_desc_p, sysinfo->syscalls, i, sysdesc);
 337        i++)
 338     if (strcmp (sysdesc->name, syscall_name) == 0)
 339       return sysdesc->number;
 340
 341   return UNKNOWN_SYSCALL;
 342 }
 343
 344 static const char *
 345 xml_get_syscall_name (const struct syscalls_info *sysinfo,
 346                       int syscall_number)
 347 {
 348   struct syscall_desc *sysdesc;
 349   int i;
 350
 351   if (sysinfo == NULL
 352       || syscall_number < 0)
 353     return NULL;
 354
 355   for (i = 0;
 356        VEC_iterate(syscall_desc_p, sysinfo->syscalls, i, sysdesc);
 357        i++)
 358     if (sysdesc->number == syscall_number)
 359       return sysdesc->name;
 360
 361   return NULL;
 362 }
 363
 364 static const char **
 365 xml_list_of_syscalls (const struct syscalls_info *sysinfo)
 366 {
 367   struct syscall_desc *sysdesc;
 368   const char **names = NULL;
 369   int nsyscalls;
 370   int i;
 371
 372   if (sysinfo == NULL)
 373     return NULL;
 374
 375   nsyscalls = VEC_length (syscall_desc_p, sysinfo->syscalls);
 376   names = xmalloc ((nsyscalls + 1) * sizeof (char *));
 377
 378   for (i = 0;
 379        VEC_iterate (syscall_desc_p, sysinfo->syscalls, i, sysdesc);
 380        i++)
 381     names[i] = sysdesc->name;
 382
 383   names[i] = NULL;
 384
 385   return names;
 386 }
 387
 388 void
 389 set_xml_syscall_file_name (const char *name)
 390 {
 391   xml_syscall_file = name;
 392 }
 393
 394 void
 395 get_syscall_by_number (int syscall_number,
 396                        struct syscall *s)
 397 {
 398   init_sysinfo ();
 399
 400   s->number = syscall_number;
 401   s->name = xml_get_syscall_name (sysinfo, syscall_number);
 402 }
 403
 404 void
 405 get_syscall_by_name (const char *syscall_name,
 406                      struct syscall *s)
 407 {
 408   init_sysinfo ();
 409
 410   s->number = xml_get_syscall_number (sysinfo, syscall_name);
 411   s->name = syscall_name;
 412 }
 413
 414 const char **
 415 get_syscall_names (void)
 416 {
 417   init_sysinfo ();
 418
 419   return xml_list_of_syscalls (sysinfo);
 420 }
 421
 422 #endif /* ! HAVE_LIBEXPAT */