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
  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 (const char *name)
  50 {
  51   return;
  52 }
  53
  54 void
  55 get_syscall_by_number (int syscall_number,
  56                        struct syscall *s)
  57 {
  58   syscall_warn_user ();
  59   s->number = syscall_number;
  60   s->name = NULL;
  61 }
  62
  63 void
  64 get_syscall_by_name (const char *syscall_name,
  65                      struct syscall *s)
  66 {
  67   syscall_warn_user ();
  68   s->number = UNKNOWN_SYSCALL;
  69   s->name = syscall_name;
  70 }
  71
  72 const char **
  73 get_syscall_names (void)
  74 {
  75   syscall_warn_user ();
  76   return NULL;
  77 }
  78
  79 #else /* ! HAVE_LIBEXPAT */
  80
  81 /* Variable that will hold the last known data-directory.  This is useful to
  82    know whether we should re-read the XML info for the target.  */
  83 static char *my_gdb_datadir = NULL;
  84
  85 /* Structure which describes a syscall.  */
  86 typedef struct syscall_desc
  87 {
  88   /* The syscall number.  */
  89
  90   int number;
  91
  92   /* The syscall name.  */
  93
  94   char *name;
  95 } *syscall_desc_p;
  96 DEF_VEC_P(syscall_desc_p);
  97
  98 /* Structure that represents syscalls information.  */
  99 struct syscalls_info
 100 {
 101   /* The syscalls.  */
 102
 103   VEC(syscall_desc_p) *syscalls;
 104 };
 105
 106 /* Callback data for syscall information parsing.  */
 107 struct syscall_parsing_data
 108 {
 109   /* The syscalls_info we are building.  */
 110
 111   struct syscalls_info *sysinfo;
 112 };
 113
 114 /* Structure used to store information about the available syscalls in
 115    the system.  */
 116 static const struct syscalls_info *sysinfo = NULL;
 117
 118 /* A flag to tell if we already initialized the structure above.  */
 119 static int have_initialized_sysinfo = 0;
 120
 121 /* The filename of the syscall's XML.  */
 122 static const char *xml_syscall_file = NULL;
 123
 124 static struct syscalls_info *
 125 allocate_syscalls_info (void)
 126 {
 127   return XCNEW (struct syscalls_info);
 128 }
 129
 130 static void
 131 sysinfo_free_syscalls_desc (struct syscall_desc *sd)
 132 {
 133   xfree (sd->name);
 134 }
 135
 136 static void
 137 free_syscalls_info (void *arg)
 138 {
 139   struct syscalls_info *sysinfo = arg;
 140   struct syscall_desc *sysdesc;
 141   int i;
 142
 143   for (i = 0;
 144        VEC_iterate (syscall_desc_p, sysinfo->syscalls, i, sysdesc);
 145        i++)
 146     sysinfo_free_syscalls_desc (sysdesc);
 147   VEC_free (syscall_desc_p, sysinfo->syscalls);
 148
 149   xfree (sysinfo);
 150 }
 151
 152 static struct cleanup *
 153 make_cleanup_free_syscalls_info (struct syscalls_info *sysinfo)
 154 {
 155   return make_cleanup (free_syscalls_info, sysinfo);
 156 }
 157
 158 static void
 159 syscall_create_syscall_desc (struct syscalls_info *sysinfo,
 160                              const char *name, int number)
 161 {
 162   struct syscall_desc *sysdesc = XCNEW (struct syscall_desc);
 163
 164   sysdesc->name = xstrdup (name);
 165   sysdesc->number = number;
 166
 167   VEC_safe_push (syscall_desc_p, sysinfo->syscalls, sysdesc);
 168 }
 169
 170 /* Handle the start of a <syscall> element.  */
 171 static void
 172 syscall_start_syscall (struct gdb_xml_parser *parser,
 173                        const struct gdb_xml_element *element,
 174                        void *user_data, VEC(gdb_xml_value_s) *attributes)
 175 {
 176   struct syscall_parsing_data *data = user_data;
 177   struct gdb_xml_value *attrs = VEC_address (gdb_xml_value_s, attributes);
 178   int len, i;
 179   /* syscall info.  */
 180   char *name = NULL;
 181   int number = 0;
 182
 183   len = VEC_length (gdb_xml_value_s, attributes);
 184
 185   for (i = 0; i < len; i++)
 186     {
 187       if (strcmp (attrs[i].name, "name") == 0)
 188         name = attrs[i].value;
 189       else if (strcmp (attrs[i].name, "number") == 0)
 190         number = * (ULONGEST *) attrs[i].value;
 191       else
 192         internal_error (__FILE__, __LINE__,
 193                         _("Unknown attribute name '%s'."), attrs[i].name);
 194     }
 195
 196   gdb_assert (name);
 197   syscall_create_syscall_desc (data->sysinfo, name, number);
 198 }
 199
 200
 201 /* The elements and attributes of an XML syscall document.  */
 202 static const struct gdb_xml_attribute syscall_attr[] = {
 203   { "number", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
 204   { "name", GDB_XML_AF_NONE, NULL, NULL },
 205   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 206 };
 207
 208 static const struct gdb_xml_element syscalls_info_children[] = {
 209   { "syscall", syscall_attr, NULL,
 210     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 211     syscall_start_syscall, NULL },
 212   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 213 };
 214
 215 static const struct gdb_xml_element syselements[] = {
 216   { "syscalls_info", NULL, syscalls_info_children,
 217     GDB_XML_EF_NONE, NULL, NULL },
 218   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 219 };
 220
 221 static struct syscalls_info *
 222 syscall_parse_xml (const char *document, xml_fetch_another fetcher,
 223                    void *fetcher_baton)
 224 {
 225   struct cleanup *result_cleanup;
 226   struct syscall_parsing_data data;
 227
 228   data.sysinfo = allocate_syscalls_info ();
 229   result_cleanup = make_cleanup_free_syscalls_info (data.sysinfo);
 230
 231   if (gdb_xml_parse_quick (_("syscalls info"), NULL,
 232                            syselements, document, &data) == 0)
 233     {
 234       /* Parsed successfully.  */
 235       discard_cleanups (result_cleanup);
 236       return data.sysinfo;
 237     }
 238   else
 239     {
 240       warning (_("Could not load XML syscalls info; ignoring"));
 241       do_cleanups (result_cleanup);
 242       return NULL;
 243     }
 244 }
 245
 246 /* Function responsible for initializing the information
 247    about the syscalls.  It reads the XML file and fills the
 248    struct syscalls_info with the values.
 249
 250    Returns the struct syscalls_info if the file is valid, NULL otherwise.  */
 251 static const struct syscalls_info *
 252 xml_init_syscalls_info (const char *filename)
 253 {
 254   char *full_file;
 255   char *dirname;
 256   struct syscalls_info *sysinfo;
 257   struct cleanup *back_to;
 258
 259   full_file = xml_fetch_content_from_file (filename, gdb_datadir);
 260   if (full_file == NULL)
 261     return NULL;
 262
 263   back_to = make_cleanup (xfree, full_file);
 264
 265   dirname = ldirname (filename);
 266   if (dirname != NULL)
 267     make_cleanup (xfree, dirname);
 268
 269   sysinfo = syscall_parse_xml (full_file,
 270                                xml_fetch_content_from_file, dirname);
 271   do_cleanups (back_to);
 272
 273   return sysinfo;
 274 }
 275
 276 /* Initializes the syscalls_info structure according to the
 277    architecture.  */
 278 static void
 279 init_sysinfo (void)
 280 {
 281   /* Should we re-read the XML info for this target?  */
 282   if (my_gdb_datadir && filename_cmp (my_gdb_datadir, gdb_datadir) != 0)
 283     {
 284       /* The data-directory changed from the last time we used it.
 285          It means that we have to re-read the XML info.  */
 286       have_initialized_sysinfo = 0;
 287       xfree (my_gdb_datadir);
 288       my_gdb_datadir = NULL;
 289       if (sysinfo)
 290         free_syscalls_info ((void *) sysinfo);
 291     }
 292
 293   /* Did we already try to initialize the structure?  */
 294   if (have_initialized_sysinfo)
 295     return;
 296
 297   sysinfo = xml_init_syscalls_info (xml_syscall_file);
 298
 299   have_initialized_sysinfo = 1;
 300
 301   if (sysinfo == NULL)
 302     {
 303       if (xml_syscall_file)
 304         warning (_("Could not load the syscall XML file `%s/%s'."),
 305                  gdb_datadir, xml_syscall_file);
 306       else
 307         warning (_("There is no XML file to open."));
 308
 309       warning (_("GDB will not be able to display "
 310                  "syscall names nor to verify if\n"
 311                  "any provided syscall numbers are valid."));
 312     }
 313
 314   /* Saving the data-directory used to read this XML info.  */
 315   my_gdb_datadir = xstrdup (gdb_datadir);
 316 }
 317
 318 static int
 319 xml_get_syscall_number (const struct syscalls_info *sysinfo,
 320                         const char *syscall_name)
 321 {
 322   struct syscall_desc *sysdesc;
 323   int i;
 324
 325   if (sysinfo == NULL
 326       || syscall_name == NULL)
 327     return UNKNOWN_SYSCALL;
 328
 329   for (i = 0;
 330        VEC_iterate(syscall_desc_p, sysinfo->syscalls, i, sysdesc);
 331        i++)
 332     if (strcmp (sysdesc->name, syscall_name) == 0)
 333       return sysdesc->number;
 334
 335   return UNKNOWN_SYSCALL;
 336 }
 337
 338 static const char *
 339 xml_get_syscall_name (const struct syscalls_info *sysinfo,
 340                       int syscall_number)
 341 {
 342   struct syscall_desc *sysdesc;
 343   int i;
 344
 345   if (sysinfo == NULL
 346       || syscall_number < 0)
 347     return NULL;
 348
 349   for (i = 0;
 350        VEC_iterate(syscall_desc_p, sysinfo->syscalls, i, sysdesc);
 351        i++)
 352     if (sysdesc->number == syscall_number)
 353       return sysdesc->name;
 354
 355   return NULL;
 356 }
 357
 358 static const char **
 359 xml_list_of_syscalls (const struct syscalls_info *sysinfo)
 360 {
 361   struct syscall_desc *sysdesc;
 362   const char **names = NULL;
 363   int nsyscalls;
 364   int i;
 365
 366   if (sysinfo == NULL)
 367     return NULL;
 368
 369   nsyscalls = VEC_length (syscall_desc_p, sysinfo->syscalls);
 370   names = xmalloc ((nsyscalls + 1) * sizeof (char *));
 371
 372   for (i = 0;
 373        VEC_iterate (syscall_desc_p, sysinfo->syscalls, i, sysdesc);
 374        i++)
 375     names[i] = sysdesc->name;
 376
 377   names[i] = NULL;
 378
 379   return names;
 380 }
 381
 382 void
 383 set_xml_syscall_file_name (const char *name)
 384 {
 385   xml_syscall_file = name;
 386 }
 387
 388 void
 389 get_syscall_by_number (int syscall_number,
 390                        struct syscall *s)
 391 {
 392   init_sysinfo ();
 393
 394   s->number = syscall_number;
 395   s->name = xml_get_syscall_name (sysinfo, syscall_number);
 396 }
 397
 398 void
 399 get_syscall_by_name (const char *syscall_name,
 400                      struct syscall *s)
 401 {
 402   init_sysinfo ();
 403
 404   s->number = xml_get_syscall_number (sysinfo, syscall_name);
 405   s->name = syscall_name;
 406 }
 407
 408 const char **
 409 get_syscall_names (void)
 410 {
 411   init_sysinfo ();
 412
 413   return xml_list_of_syscalls (sysinfo);
 414 }
 415
 416 #endif /* ! HAVE_LIBEXPAT */