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 #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 XCNEW (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 static 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 = XCNEW (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   gdb_assert (name);
 199   syscall_create_syscall_desc (data->sysinfo, name, number);
 200 }
 201
 202
 203 /* The elements and attributes of an XML syscall document.  */
 204 static const struct gdb_xml_attribute syscall_attr[] = {
 205   { "number", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
 206   { "name", GDB_XML_AF_NONE, NULL, NULL },
 207   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 208 };
 209
 210 static const struct gdb_xml_element syscalls_info_children[] = {
 211   { "syscall", syscall_attr, NULL,
 212     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 213     syscall_start_syscall, NULL },
 214   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 215 };
 216
 217 static const struct gdb_xml_element syselements[] = {
 218   { "syscalls_info", NULL, syscalls_info_children,
 219     GDB_XML_EF_NONE, NULL, NULL },
 220   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 221 };
 222
 223 static struct syscalls_info *
 224 syscall_parse_xml (const char *document, xml_fetch_another fetcher,
 225                    void *fetcher_baton)
 226 {
 227   struct cleanup *result_cleanup;
 228   struct syscall_parsing_data data;
 229
 230   data.sysinfo = allocate_syscalls_info ();
 231   result_cleanup = make_cleanup_free_syscalls_info (data.sysinfo);
 232
 233   if (gdb_xml_parse_quick (_("syscalls info"), NULL,
 234                            syselements, document, &data) == 0)
 235     {
 236       /* Parsed successfully.  */
 237       discard_cleanups (result_cleanup);
 238       return data.sysinfo;
 239     }
 240   else
 241     {
 242       warning (_("Could not load XML syscalls info; ignoring"));
 243       do_cleanups (result_cleanup);
 244       return NULL;
 245     }
 246 }
 247
 248 /* Function responsible for initializing the information
 249    about the syscalls.  It reads the XML file and fills the
 250    struct syscalls_info with the values.
 251
 252    Returns the struct syscalls_info if the file is valid, NULL otherwise.  */
 253 static const struct syscalls_info *
 254 xml_init_syscalls_info (const char *filename)
 255 {
 256   char *full_file;
 257   char *dirname;
 258   struct syscalls_info *sysinfo;
 259   struct cleanup *back_to;
 260
 261   full_file = xml_fetch_content_from_file (filename, gdb_datadir);
 262   if (full_file == NULL)
 263     return NULL;
 264
 265   back_to = make_cleanup (xfree, full_file);
 266
 267   dirname = ldirname (filename);
 268   if (dirname != NULL)
 269     make_cleanup (xfree, dirname);
 270
 271   sysinfo = syscall_parse_xml (full_file,
 272                                xml_fetch_content_from_file, dirname);
 273   do_cleanups (back_to);
 274
 275   return sysinfo;
 276 }
 277
 278 /* Initializes the syscalls_info structure according to the
 279    architecture.  */
 280 static void
 281 init_sysinfo (void)
 282 {
 283   /* Should we re-read the XML info for this target?  */
 284   if (my_gdb_datadir && filename_cmp (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       have_initialized_sysinfo = 0;
 289       xfree (my_gdb_datadir);
 290       my_gdb_datadir = NULL;
 291       if (sysinfo)
 292         free_syscalls_info ((void *) sysinfo);
 293     }
 294
 295   /* Did we already try to initialize the structure?  */
 296   if (have_initialized_sysinfo)
 297     return;
 298
 299   sysinfo = xml_init_syscalls_info (xml_syscall_file);
 300
 301   have_initialized_sysinfo = 1;
 302
 303   if (sysinfo == NULL)
 304     {
 305       if (xml_syscall_file)
 306         warning (_("Could not load the syscall XML file `%s/%s'."),
 307                  gdb_datadir, xml_syscall_file);
 308       else
 309         warning (_("There is no XML file to open."));
 310
 311       warning (_("GDB will not be able to display "
 312                  "syscall names nor to verify if\n"
 313                  "any provided syscall numbers are valid."));
 314     }
 315
 316   /* Saving the data-directory used to read this XML info.  */
 317   my_gdb_datadir = xstrdup (gdb_datadir);
 318 }
 319
 320 static int
 321 xml_get_syscall_number (const struct syscalls_info *sysinfo,
 322                         const char *syscall_name)
 323 {
 324   struct syscall_desc *sysdesc;
 325   int i;
 326
 327   if (sysinfo == NULL
 328       || syscall_name == NULL)
 329     return UNKNOWN_SYSCALL;
 330
 331   for (i = 0;
 332        VEC_iterate(syscall_desc_p, sysinfo->syscalls, i, sysdesc);
 333        i++)
 334     if (strcmp (sysdesc->name, syscall_name) == 0)
 335       return sysdesc->number;
 336
 337   return UNKNOWN_SYSCALL;
 338 }
 339
 340 static const char *
 341 xml_get_syscall_name (const struct syscalls_info *sysinfo,
 342                       int syscall_number)
 343 {
 344   struct syscall_desc *sysdesc;
 345   int i;
 346
 347   if (sysinfo == NULL
 348       || syscall_number < 0)
 349     return NULL;
 350
 351   for (i = 0;
 352        VEC_iterate(syscall_desc_p, sysinfo->syscalls, i, sysdesc);
 353        i++)
 354     if (sysdesc->number == syscall_number)
 355       return sysdesc->name;
 356
 357   return NULL;
 358 }
 359
 360 static const char **
 361 xml_list_of_syscalls (const struct syscalls_info *sysinfo)
 362 {
 363   struct syscall_desc *sysdesc;
 364   const char **names = NULL;
 365   int nsyscalls;
 366   int i;
 367
 368   if (sysinfo == NULL)
 369     return NULL;
 370
 371   nsyscalls = VEC_length (syscall_desc_p, sysinfo->syscalls);
 372   names = xmalloc ((nsyscalls + 1) * sizeof (char *));
 373
 374   for (i = 0;
 375        VEC_iterate (syscall_desc_p, sysinfo->syscalls, i, sysdesc);
 376        i++)
 377     names[i] = sysdesc->name;
 378
 379   names[i] = NULL;
 380
 381   return names;
 382 }
 383
 384 void
 385 set_xml_syscall_file_name (const char *name)
 386 {
 387   xml_syscall_file = name;
 388 }
 389
 390 void
 391 get_syscall_by_number (int syscall_number,
 392                        struct syscall *s)
 393 {
 394   init_sysinfo ();
 395
 396   s->number = syscall_number;
 397   s->name = xml_get_syscall_name (sysinfo, syscall_number);
 398 }
 399
 400 void
 401 get_syscall_by_name (const char *syscall_name,
 402                      struct syscall *s)
 403 {
 404   init_sysinfo ();
 405
 406   s->number = xml_get_syscall_number (sysinfo, syscall_name);
 407   s->name = syscall_name;
 408 }
 409
 410 const char **
 411 get_syscall_names (void)
 412 {
 413   init_sysinfo ();
 414
 415   return xml_list_of_syscalls (sysinfo);
 416 }
 417
 418 #endif /* ! HAVE_LIBEXPAT */