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/* Functions that provide the mechanism to parse a syscall XML file

   and get its values.

   Copyright (C) 2009, 2010 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)

{

  return;

}

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 */

/* Variable that will hold the last known data-directory.  This is useful to

   know whether we should re-read the XML info for the target.  */

static char *my_gdb_datadir = NULL;

/* 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 <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, NULL, 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;

  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)

    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)

{

  /* Should we re-read the XML info for this target?  */

  if (my_gdb_datadir && strcmp (my_gdb_datadir, gdb_datadir) != 0)

    {

      /* The data-directory changed from the last time we used it.

         It means that we have to re-read the XML info.  */

      have_initialized_sysinfo = 0;

      xfree (my_gdb_datadir);

      my_gdb_datadir = NULL;

      if (sysinfo)

        free_syscalls_info ((void *) sysinfo);

    }

  /* Did we already try to initialize the structure?  */

  if (have_initialized_sysinfo)

    return;

  sysinfo = xml_init_syscalls_info (xml_syscall_file);

  have_initialized_sysinfo = 1;

  if (sysinfo == NULL)

    {

      if (xml_syscall_file)

        warning (_("\

Could not load the syscall XML file `%s/%s'."),

                 gdb_datadir, xml_syscall_file);

      else

        warning (_("\

There is no XML file to open."));

      warning (_("\

GDB will not be able to display syscall names nor to verify if\n\

any provided syscall numbers are valid."));

    }

  /* Saving the data-directory used to read this XML info.  */

  my_gdb_datadir = xstrdup (gdb_datadir);

}

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 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 */