gdb/xml-syscall.c

/* Functions that provide the mechanism to parse a syscall XML file
   and get its values.

   Copyright (C) 1986, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996,
   1998, 1999, 2000, 2001, 2003, 2004, 2005, 2006, 2007, 2008
   Free Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include "defs.h"
#include "gdbtypes.h"
#include "xml-support.h"
#include "xml-syscall.h"

/* For the struct syscall definition.  */
#include "target.h"

#include "filenames.h"

#include "gdb_assert.h"

#ifndef HAVE_LIBEXPAT

/* Dummy functions to indicate that there's no support for fetching
   syscalls information.  */

static void
syscall_warn_user (void)
{
  static int have_warned = 0;
  if (!have_warned)
    {
      have_warned = 1;
      warning (_("Can not parse XML syscalls information; XML support was "
		 "disabled at compile time."));
    }
}

void
set_xml_syscall_file_name (const char *name)
{
  syscall_warn_user ();
}

void
get_syscall_by_number (int syscall_number,
                       struct syscall *s)
{
  syscall_warn_user ();
  s->number = syscall_number;
  s->name = NULL;
}

void
get_syscall_by_name (const char *syscall_name,
                     struct syscall *s)
{
  syscall_warn_user ();
  s->number = UNKNOWN_SYSCALL;
  s->name = syscall_name;
}

const char **
get_syscall_names (void)
{
  syscall_warn_user ();
  return NULL;
}


#else /* ! HAVE_LIBEXPAT */

/* Structure which describes a syscall.  */
typedef struct syscall_desc
{
  /* The syscall number.  */

  int number;

  /* The syscall name.  */

  char *name;
} *syscall_desc_p;
DEF_VEC_P(syscall_desc_p);

/* Structure that represents syscalls information.  */
struct syscalls_info
{
  /* The syscalls.  */

  VEC(syscall_desc_p) *syscalls;
};

/* Callback data for syscall information parsing.  */
struct syscall_parsing_data
{
  /* The syscalls_info we are building.  */

  struct syscalls_info *sysinfo;
};

/* Structure used to store information about the available syscalls in
   the system.  */
static const struct syscalls_info *_sysinfo = NULL;

/* A flag to tell if we already initialized the structure above.  */
static int have_initialized_sysinfo = 0;

/* The filename of the syscall's XML.  */
static const char *xml_syscall_file = NULL;

static struct syscalls_info *
allocate_syscalls_info (void)
{
  return XZALLOC (struct syscalls_info);
}

static void
sysinfo_free_syscalls_desc (struct syscall_desc *sd)
{
  xfree (sd->name);
}

static void
free_syscalls_info (void *arg)
{
  struct syscalls_info *sysinfo = arg;
  struct syscall_desc *sysdesc;
  int i;

  for (i = 0;
       VEC_iterate (syscall_desc_p, sysinfo->syscalls, i, sysdesc);
       i++)
    sysinfo_free_syscalls_desc (sysdesc);
  VEC_free (syscall_desc_p, sysinfo->syscalls);

  xfree (sysinfo);
}

struct cleanup *
make_cleanup_free_syscalls_info (struct syscalls_info *sysinfo)
{
  return make_cleanup (free_syscalls_info, sysinfo);
}

static void
syscall_create_syscall_desc (struct syscalls_info *sysinfo,
                             const char *name, int number)
{
  struct syscall_desc *sysdesc = XZALLOC (struct syscall_desc);

  sysdesc->name = xstrdup (name);
  sysdesc->number = number;

  VEC_safe_push (syscall_desc_p, sysinfo->syscalls, sysdesc);
}

/* Handle the start of a <syscalls_info> element.  */
static void
syscall_start_syscalls_info (struct gdb_xml_parser *parser,
                             const struct gdb_xml_element *element,
                             void *user_data,
                             VEC(gdb_xml_value_s) *attributes)
{
  struct syscall_parsing_data *data = user_data;
  struct syscalls_info *sysinfo = data->sysinfo;
}

/* Handle the start of a <syscall> element.  */
static void
syscall_start_syscall (struct gdb_xml_parser *parser,
                       const struct gdb_xml_element *element,
                       void *user_data, VEC(gdb_xml_value_s) *attributes)
{
  struct syscall_parsing_data *data = user_data;
  struct gdb_xml_value *attrs = VEC_address (gdb_xml_value_s, attributes);
  int len, i;
  /* syscall info.  */
  char *name = NULL;
  int number = 0;

  len = VEC_length (gdb_xml_value_s, attributes);

  for (i = 0; i < len; i++)
    {
      if (strcmp (attrs[i].name, "name") == 0)
        name = attrs[i].value;
      else if (strcmp (attrs[i].name, "number") == 0)
        number = * (ULONGEST *) attrs[i].value;
      else
        internal_error (__FILE__, __LINE__,
                        _("Unknown attribute name '%s'."), attrs[i].name);
    }

  syscall_create_syscall_desc (data->sysinfo, name, number);
}


/* The elements and attributes of an XML syscall document.  */
static const struct gdb_xml_attribute syscall_attr[] = {
  { "number", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
  { "name", GDB_XML_AF_NONE, NULL, NULL },
  { NULL, GDB_XML_AF_NONE, NULL, NULL }
};

static const struct gdb_xml_element syscalls_info_children[] = {
  { "syscall", syscall_attr, NULL,
    GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
    syscall_start_syscall, NULL },
  { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
};

static const struct gdb_xml_element syselements[] = {
  { "syscalls_info", NULL, syscalls_info_children,
    GDB_XML_EF_NONE, syscall_start_syscalls_info, NULL },
  { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
};

static struct syscalls_info *
syscall_parse_xml (const char *document, xml_fetch_another fetcher,
                   void *fetcher_baton)
{
  struct cleanup *result_cleanup;
  struct gdb_xml_parser *parser;
  struct syscall_parsing_data data;
  char *expanded_text;
  int i;

  parser = gdb_xml_create_parser_and_cleanup (_("syscalls info"),
					      syselements, &data);

  memset (&data, 0, sizeof (struct syscall_parsing_data));
  data.sysinfo = allocate_syscalls_info ();
  result_cleanup = make_cleanup_free_syscalls_info (data.sysinfo);

  if (gdb_xml_parse (parser, document) == 0)
    {
      /* Parsed successfully.  */
      discard_cleanups (result_cleanup);
      return data.sysinfo;
    }
  else
    {
      warning (_("Could not load XML syscalls info; ignoring"));
      do_cleanups (result_cleanup);
      return NULL;
    }
}

/* Function responsible for initializing the information
   about the syscalls.  It reads the XML file and fills the
   struct syscalls_info with the values.
   
   Returns the struct syscalls_info if the file is valid, NULL otherwise.  */
static const struct syscalls_info *
xml_init_syscalls_info (const char *filename)
{
  char *full_file;
  char *dirname;
  struct syscalls_info *sysinfo;
  struct cleanup *back_to;

  full_file = xml_fetch_content_from_file (filename, gdb_datadir);
  if (full_file == NULL)
    {
      warning (_("Could not open \"%s\""), filename);
      return NULL;
    }

  back_to = make_cleanup (xfree, full_file);

  dirname = ldirname (filename);
  if (dirname != NULL)
    make_cleanup (xfree, dirname);

  sysinfo = syscall_parse_xml (full_file, xml_fetch_content_from_file, dirname);
  do_cleanups (back_to);

  return sysinfo;
}

/* Initializes the syscalls_info structure according to the
   architecture.  */
static void
init_sysinfo (void)
{
  /* Did we already try to initialize the structure?  */
  if (have_initialized_sysinfo)
    return;
/*  if (xml_syscall_file == NULL)
    internal_error (__FILE__, __LINE__,
                    _("This architecture has not set the XML syscall file "
                      "name.  This is a bug and should not happen; please "
                      "report it.")); */

  _sysinfo = xml_init_syscalls_info (xml_syscall_file);

  have_initialized_sysinfo = 1;

  if (_sysinfo == NULL)
    {
      if (xml_syscall_file)
        /* The initialization failed.  Let's show a warning
           message to the user (just this time) and leave.  */
        warning (_("Could not load the syscall XML file `%s'.\n\
GDB will not be able to display syscall names."), xml_syscall_file);
      else
        /* There's no file to open.  Let's warn the user.  */
        warning (_("There is no XML file to open.\n\
GDB will not be able to display syscall names."));
    }
}

static int
xml_get_syscall_number (const struct syscalls_info *sysinfo,
                        const char *syscall_name)
{
  struct syscall_desc *sysdesc;
  int i;

  if (sysinfo == NULL
      || syscall_name == NULL)
    return UNKNOWN_SYSCALL;

  for (i = 0;
       VEC_iterate(syscall_desc_p, sysinfo->syscalls, i, sysdesc);
       i++)
    if (strcmp (sysdesc->name, syscall_name) == 0)
      return sysdesc->number;

  return UNKNOWN_SYSCALL;
}

static const char *
xml_get_syscall_name (const struct syscalls_info *sysinfo,
                      int syscall_number)
{
  struct syscall_desc *sysdesc;
  int i;

  if (sysinfo == NULL
      || syscall_number < 0)
    return NULL;

  for (i = 0;
       VEC_iterate(syscall_desc_p, sysinfo->syscalls, i, sysdesc);
       i++)
    if (sysdesc->number == syscall_number)
      return sysdesc->name;

  return NULL;
}

static int
xml_number_of_syscalls (const struct syscalls_info *sysinfo)
{
  return (sysinfo == NULL ? 0 : VEC_length (syscall_desc_p,
                                            sysinfo->syscalls));
}

static const char **
xml_list_of_syscalls (const struct syscalls_info *sysinfo)
{
  struct syscall_desc *sysdesc;
  const char **names = NULL;
  int nsyscalls;
  int i;

  if (sysinfo == NULL)
    return NULL;

  nsyscalls = VEC_length (syscall_desc_p, sysinfo->syscalls);
  names = xmalloc ((nsyscalls + 1) * sizeof (char *));

  for (i = 0;
       VEC_iterate (syscall_desc_p, sysinfo->syscalls, i, sysdesc);
       i++)
    names[i] = sysdesc->name;

  names[i] = NULL;

  return names;
}

void
set_xml_syscall_file_name (const char *name)
{
  xml_syscall_file = name;
}

void
get_syscall_by_number (int syscall_number,
                       struct syscall *s)
{
  init_sysinfo ();

  s->number = syscall_number;
  s->name = xml_get_syscall_name (_sysinfo, syscall_number);
}

void
get_syscall_by_name (const char *syscall_name,
                     struct syscall *s)
{
  init_sysinfo ();

  s->number = xml_get_syscall_number (_sysinfo, syscall_name);
  s->name = syscall_name;
}

const char **
get_syscall_names (void)
{
  init_sysinfo ();

  return xml_list_of_syscalls (_sysinfo);
}

#endif /* ! HAVE_LIBEXPAT */