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  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 /* 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
 104 /* Callback data for syscall information parsing.  */
 105 struct syscall_parsing_data
 106 {
 107   /* The syscalls_info we are building.  */
 108
 109   struct syscalls_info *sysinfo;
 110 };
 111
 112 /* Structure used to store information about the available syscalls in
 113    the system.  */
 114 static const struct syscalls_info *sysinfo = NULL;
 115
 116 /* A flag to tell if we already initialized the structure above.  */
 117 static int have_initialized_sysinfo = 0;
 118
 119 /* The filename of the syscall's XML.  */
 120 static const char *xml_syscall_file = NULL;
 121
 122 static struct syscalls_info *
 123 allocate_syscalls_info (void)
 124 {
 125   return XZALLOC (struct syscalls_info);
 126 }
 127
 128 static void
 129 sysinfo_free_syscalls_desc (struct syscall_desc *sd)
 130 {
 131   xfree (sd->name);
 132 }
 133
 134 static void
 135 free_syscalls_info (void *arg)
 136 {
 137   struct syscalls_info *sysinfo = arg;
 138   struct syscall_desc *sysdesc;
 139   int i;
 140
 141   for (i = 0;
 142        VEC_iterate (syscall_desc_p, sysinfo->syscalls, i, sysdesc);
 143        i++)
 144     sysinfo_free_syscalls_desc (sysdesc);
 145   VEC_free (syscall_desc_p, sysinfo->syscalls);
 146
 147   xfree (sysinfo);
 148 }
 149
 150 struct cleanup *
 151 make_cleanup_free_syscalls_info (struct syscalls_info *sysinfo)
 152 {
 153   return make_cleanup (free_syscalls_info, sysinfo);
 154 }
 155
 156 static void
 157 syscall_create_syscall_desc (struct syscalls_info *sysinfo,
 158                              const char *name, int number)
 159 {
 160   struct syscall_desc *sysdesc = XZALLOC (struct syscall_desc);
 161
 162   sysdesc->name = xstrdup (name);
 163   sysdesc->number = number;
 164
 165   VEC_safe_push (syscall_desc_p, sysinfo->syscalls, sysdesc);
 166 }
 167
 168 /* Handle the start of a <syscalls_info> element.  */
 169 static void
 170 syscall_start_syscalls_info (struct gdb_xml_parser *parser,
 171                              const struct gdb_xml_element *element,
 172                              void *user_data,
 173                              VEC(gdb_xml_value_s) *attributes)
 174 {
 175   struct syscall_parsing_data *data = user_data;
 176   struct syscalls_info *sysinfo = data->sysinfo;
 177 }
 178
 179 /* Handle the start of a <syscall> element.  */
 180 static void
 181 syscall_start_syscall (struct gdb_xml_parser *parser,
 182                        const struct gdb_xml_element *element,
 183                        void *user_data, VEC(gdb_xml_value_s) *attributes)
 184 {
 185   struct syscall_parsing_data *data = user_data;
 186   struct gdb_xml_value *attrs = VEC_address (gdb_xml_value_s, attributes);
 187   int len, i;
 188   /* syscall info.  */
 189   char *name = NULL;
 190   int number = 0;
 191
 192   len = VEC_length (gdb_xml_value_s, attributes);
 193
 194   for (i = 0; i < len; i++)
 195     {
 196       if (strcmp (attrs[i].name, "name") == 0)
 197         name = attrs[i].value;
 198       else if (strcmp (attrs[i].name, "number") == 0)
 199         number = * (ULONGEST *) attrs[i].value;
 200       else
 201         internal_error (__FILE__, __LINE__,
 202                         _("Unknown attribute name '%s'."), attrs[i].name);
 203     }
 204
 205   syscall_create_syscall_desc (data->sysinfo, name, number);
 206 }
 207
 208
 209 /* The elements and attributes of an XML syscall document.  */
 210 static const struct gdb_xml_attribute syscall_attr[] = {
 211   { "number", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
 212   { "name", GDB_XML_AF_NONE, NULL, NULL },
 213   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 214 };
 215
 216 static const struct gdb_xml_element syscalls_info_children[] = {
 217   { "syscall", syscall_attr, NULL,
 218     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 219     syscall_start_syscall, NULL },
 220   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 221 };
 222
 223 static const struct gdb_xml_element syselements[] = {
 224   { "syscalls_info", NULL, syscalls_info_children,
 225     GDB_XML_EF_NONE, syscall_start_syscalls_info, NULL },
 226   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 227 };
 228
 229 static struct syscalls_info *
 230 syscall_parse_xml (const char *document, xml_fetch_another fetcher,
 231                    void *fetcher_baton)
 232 {
 233   struct cleanup *result_cleanup;
 234   struct gdb_xml_parser *parser;
 235   struct syscall_parsing_data data;
 236   char *expanded_text;
 237   int i;
 238
 239   parser = gdb_xml_create_parser_and_cleanup (_("syscalls info"),
 240                                               syselements, &data);
 241
 242   memset (&data, 0, sizeof (struct syscall_parsing_data));
 243   data.sysinfo = allocate_syscalls_info ();
 244   result_cleanup = make_cleanup_free_syscalls_info (data.sysinfo);
 245
 246   if (gdb_xml_parse (parser, document) == 0)
 247     {
 248       /* Parsed successfully.  */
 249       discard_cleanups (result_cleanup);
 250       return data.sysinfo;
 251     }
 252   else
 253     {
 254       warning (_("Could not load XML syscalls info; ignoring"));
 255       do_cleanups (result_cleanup);
 256       return NULL;
 257     }
 258 }
 259
 260 /* Function responsible for initializing the information
 261    about the syscalls.  It reads the XML file and fills the
 262    struct syscalls_info with the values.
 263
 264    Returns the struct syscalls_info if the file is valid, NULL otherwise.  */
 265 static const struct syscalls_info *
 266 xml_init_syscalls_info (const char *filename)
 267 {
 268   char *full_file;
 269   char *dirname;
 270   struct syscalls_info *sysinfo;
 271   struct cleanup *back_to;
 272
 273   full_file = xml_fetch_content_from_file (filename, gdb_datadir);
 274   if (full_file == NULL)
 275     return NULL;
 276
 277   back_to = make_cleanup (xfree, full_file);
 278
 279   dirname = ldirname (filename);
 280   if (dirname != NULL)
 281     make_cleanup (xfree, dirname);
 282
 283   sysinfo = syscall_parse_xml (full_file, xml_fetch_content_from_file, dirname);
 284   do_cleanups (back_to);
 285
 286   return sysinfo;
 287 }
 288
 289 /* Initializes the syscalls_info structure according to the
 290    architecture.  */
 291 static void
 292 init_sysinfo (void)
 293 {
 294   /* Did we already try to initialize the structure?  */
 295   if (have_initialized_sysinfo)
 296     return;
 297
 298   sysinfo = xml_init_syscalls_info (xml_syscall_file);
 299
 300   have_initialized_sysinfo = 1;
 301
 302   if (sysinfo == NULL)
 303     {
 304       if (xml_syscall_file)
 305         warning (_("\
 306 Could not load the syscall XML file `%s'."), xml_syscall_file);
 307       else
 308         warning (_("\
 309 There is no XML file to open."));
 310
 311       warning (_("\
 312 GDB will not be able to display syscall names nor to verify if\n\
 313 any provided syscall numbers are valid."));
 314     }
 315 }
 316
 317 static int
 318 xml_get_syscall_number (const struct syscalls_info *sysinfo,
 319                         const char *syscall_name)
 320 {
 321   struct syscall_desc *sysdesc;
 322   int i;
 323
 324   if (sysinfo == NULL
 325       || syscall_name == NULL)
 326     return UNKNOWN_SYSCALL;
 327
 328   for (i = 0;
 329        VEC_iterate(syscall_desc_p, sysinfo->syscalls, i, sysdesc);
 330        i++)
 331     if (strcmp (sysdesc->name, syscall_name) == 0)
 332       return sysdesc->number;
 333
 334   return UNKNOWN_SYSCALL;
 335 }
 336
 337 static const char *
 338 xml_get_syscall_name (const struct syscalls_info *sysinfo,
 339                       int syscall_number)
 340 {
 341   struct syscall_desc *sysdesc;
 342   int i;
 343
 344   if (sysinfo == NULL
 345       || syscall_number < 0)
 346     return NULL;
 347
 348   for (i = 0;
 349        VEC_iterate(syscall_desc_p, sysinfo->syscalls, i, sysdesc);
 350        i++)
 351     if (sysdesc->number == syscall_number)
 352       return sysdesc->name;
 353
 354   return NULL;
 355 }
 356
 357 static int
 358 xml_number_of_syscalls (const struct syscalls_info *sysinfo)
 359 {
 360   return (sysinfo == NULL ? 0 : VEC_length (syscall_desc_p,
 361                                             sysinfo->syscalls));
 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 */