dbus-sysdeps.c

/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
/* dbus-sysdeps.c Wrappers around system/libc features shared between UNIX and Windows (internal to D-Bus implementation)
 * 
 * Copyright (C) 2002, 2003, 2006  Red Hat, Inc.
 * Copyright (C) 2003 CodeFactory AB
 *
 * Licensed under the Academic Free License version 2.1
 * 
 * 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 2 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, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */

#include <config.h>
#include "dbus-internals.h"
#include "dbus-sysdeps.h"
#include "dbus-threads.h"
#include "dbus-protocol.h"
#include "dbus-string.h"
#include "dbus-list.h"

/* NOTE: If you include any unix/windows-specific headers here, you are probably doing something
 * wrong and should be putting some code in dbus-sysdeps-unix.c or dbus-sysdeps-win.c.
 *
 * These are the standard ANSI C headers...
 */
#if HAVE_LOCALE_H
#include <locale.h>
#endif
#include <stdlib.h>
#include <string.h>
#include <stdio.h>

#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif

_DBUS_DEFINE_GLOBAL_LOCK (win_fds);
_DBUS_DEFINE_GLOBAL_LOCK (sid_atom_cache);
_DBUS_DEFINE_GLOBAL_LOCK (system_users);

#ifdef DBUS_WIN
  #include <stdlib.h>
#elif (defined __APPLE__)
# include <crt_externs.h>
# define environ (*_NSGetEnviron())
#else
extern char **environ;
#endif

void
_dbus_abort (void)
{
  const char *s;
  
  _dbus_print_backtrace ();
  
  s = _dbus_getenv ("DBUS_BLOCK_ON_ABORT");
  if (s && *s)
    {
      /* don't use _dbus_warn here since it can _dbus_abort() */
      fprintf (stderr, "  Process %lu sleeping for gdb attach\n", _dbus_pid_for_log ());
      _dbus_sleep_milliseconds (1000 * 180);
    }
  
  abort ();
  _dbus_exit (1); /* in case someone manages to ignore SIGABRT ? */
}

dbus_bool_t
_dbus_setenv (const char *varname,
              const char *value)
{
  _dbus_assert (varname != NULL);
  
  if (value == NULL)
    {
#ifdef HAVE_UNSETENV
      unsetenv (varname);
      return TRUE;
#else
      char *putenv_value;
      size_t len;

      len = strlen (varname);

      /* Use system malloc to avoid memleaks that dbus_malloc
       * will get upset about.
       */
      
      putenv_value = malloc (len + 2);
      if (putenv_value == NULL)
        return FALSE;

      strcpy (putenv_value, varname);
#if defined(DBUS_WIN)
      strcat (putenv_value, "=");
#endif
      
      return (putenv (putenv_value) == 0);
#endif
    }
  else
    {
#ifdef HAVE_SETENV
      return (setenv (varname, value, TRUE) == 0);
#else
      char *putenv_value;
      size_t len;
      size_t varname_len;
      size_t value_len;

      varname_len = strlen (varname);
      value_len = strlen (value);
      
      len = varname_len + value_len + 1 /* '=' */ ;

      /* Use system malloc to avoid memleaks that dbus_malloc
       * will get upset about.
       */
      
      putenv_value = malloc (len + 1);
      if (putenv_value == NULL)
        return FALSE;

      strcpy (putenv_value, varname);
      strcpy (putenv_value + varname_len, "=");
      strcpy (putenv_value + varname_len + 1, value);
      
      return (putenv (putenv_value) == 0);
#endif
    }
}

const char*
_dbus_getenv (const char *varname)
{  
  /* Don't respect any environment variables if the current process is
   * setuid.  This is the equivalent of glibc's __secure_getenv().
   */
  if (_dbus_check_setuid ())
    return NULL;
  return getenv (varname);
}

dbus_bool_t
_dbus_clearenv (void)
{
  dbus_bool_t rc = TRUE;

#ifdef HAVE_CLEARENV
  if (clearenv () != 0)
     rc = FALSE;
#else

  if (environ != NULL)
    environ[0] = NULL;
#endif

  return rc;
}

char **
_dbus_get_environment (void)
{
  int i, length;
  char **environment;

  _dbus_assert (environ != NULL);

  for (length = 0; environ[length] != NULL; length++);

  /* Add one for NULL */
  length++;

  environment = dbus_new0 (char *, length);

  if (environment == NULL)
    return NULL;

  for (i = 0; environ[i] != NULL; i++)
    {
      environment[i] = _dbus_strdup (environ[i]);

      if (environment[i] == NULL)
        break;
    }

  if (environ[i] != NULL)
    {
      dbus_free_string_array (environment);
      environment = NULL;
    }

  return environment;
}

dbus_bool_t
_dbus_split_paths_and_append (DBusString *dirs, 
                              const char *suffix, 
                              DBusList  **dir_list)
{
   int start;
   int i;
   int len;
   char *cpath;
   DBusString file_suffix;

   start = 0;
   i = 0;

   _dbus_string_init_const (&file_suffix, suffix);

   len = _dbus_string_get_length (dirs);

   while (_dbus_string_find (dirs, start, _DBUS_PATH_SEPARATOR, &i))
     {
       DBusString path;

       if (!_dbus_string_init (&path))
          goto oom;

       if (!_dbus_string_copy_len (dirs,
                                   start,
                                   i - start,
                                   &path,
                                   0))
          {
            _dbus_string_free (&path);
            goto oom;
          }

        _dbus_string_chop_white (&path);

        /* check for an empty path */
        if (_dbus_string_get_length (&path) == 0)
          goto next;

        if (!_dbus_concat_dir_and_file (&path,
                                        &file_suffix))
          {
            _dbus_string_free (&path);
            goto oom;
          }

        if (!_dbus_string_copy_data(&path, &cpath))
          {
            _dbus_string_free (&path);
            goto oom;
          }

        if (!_dbus_list_append (dir_list, cpath))
          {
            _dbus_string_free (&path);              
            dbus_free (cpath);
            goto oom;
          }

       next:
        _dbus_string_free (&path);
        start = i + 1;
    } 
      
  if (start != len)
    { 
      DBusString path;

      if (!_dbus_string_init (&path))
        goto oom;

      if (!_dbus_string_copy_len (dirs,
                                  start,
                                  len - start,
                                  &path,
                                  0))
        {
          _dbus_string_free (&path);
          goto oom;
        }

      if (!_dbus_concat_dir_and_file (&path,
                                      &file_suffix))
        {
          _dbus_string_free (&path);
          goto oom;
        }

      if (!_dbus_string_copy_data(&path, &cpath))
        {
          _dbus_string_free (&path);
          goto oom;
        }

      if (!_dbus_list_append (dir_list, cpath))
        {
          _dbus_string_free (&path);              
          dbus_free (cpath);
          goto oom;
        }

      _dbus_string_free (&path); 
    }

  return TRUE;

 oom:
  _dbus_list_foreach (dir_list, (DBusForeachFunction)dbus_free, NULL); 
  _dbus_list_clear (dir_list);
  return FALSE;
}

dbus_bool_t
_dbus_string_append_int (DBusString *str,
                         long        value)
{
  /* this calculation is from comp.lang.c faq */
#define MAX_LONG_LEN ((sizeof (long) * 8 + 2) / 3 + 1)  /* +1 for '-' */
  int orig_len;
  int i;
  char *buf;
  
  orig_len = _dbus_string_get_length (str);

  if (!_dbus_string_lengthen (str, MAX_LONG_LEN))
    return FALSE;

  buf = _dbus_string_get_data_len (str, orig_len, MAX_LONG_LEN);

  snprintf (buf, MAX_LONG_LEN, "%ld", value);

  i = 0;
  while (*buf)
    {
      ++buf;
      ++i;
    }
  
  _dbus_string_shorten (str, MAX_LONG_LEN - i);
  
  return TRUE;
}

dbus_bool_t
_dbus_string_append_uint (DBusString    *str,
                          unsigned long  value)
{
  /* this is wrong, but definitely on the high side. */
#define MAX_ULONG_LEN (MAX_LONG_LEN * 2)
  int orig_len;
  int i;
  char *buf;
  
  orig_len = _dbus_string_get_length (str);

  if (!_dbus_string_lengthen (str, MAX_ULONG_LEN))
    return FALSE;

  buf = _dbus_string_get_data_len (str, orig_len, MAX_ULONG_LEN);

  snprintf (buf, MAX_ULONG_LEN, "%lu", value);

  i = 0;
  while (*buf)
    {
      ++buf;
      ++i;
    }
  
  _dbus_string_shorten (str, MAX_ULONG_LEN - i);
  
  return TRUE;
}

#ifdef DBUS_BUILD_TESTS

dbus_bool_t
_dbus_string_append_double (DBusString *str,
                            double      value)
{
#define MAX_DOUBLE_LEN 64 /* this is completely made up :-/ */
  int orig_len;
  char *buf;
  int i;
  
  orig_len = _dbus_string_get_length (str);

  if (!_dbus_string_lengthen (str, MAX_DOUBLE_LEN))
    return FALSE;

  buf = _dbus_string_get_data_len (str, orig_len, MAX_DOUBLE_LEN);

  snprintf (buf, MAX_LONG_LEN, "%g", value);

  i = 0;
  while (*buf)
    {
      ++buf;
      ++i;
    }
  
  _dbus_string_shorten (str, MAX_DOUBLE_LEN - i);
  
  return TRUE;
}
#endif /* DBUS_BUILD_TESTS */

dbus_bool_t
_dbus_string_parse_int (const DBusString *str,
                        int               start,
                        long             *value_return,
                        int              *end_return)
{
  long v;
  const char *p;
  char *end;

  p = _dbus_string_get_const_data_len (str, start,
                                       _dbus_string_get_length (str) - start);

  end = NULL;
  _dbus_set_errno_to_zero ();
  v = strtol (p, &end, 0);
  if (end == NULL || end == p || errno != 0)
    return FALSE;

  if (value_return)
    *value_return = v;
  if (end_return)
    *end_return = start + (end - p);

  return TRUE;
}

dbus_bool_t
_dbus_string_parse_uint (const DBusString *str,
                         int               start,
                         unsigned long    *value_return,
                         int              *end_return)
{
  unsigned long v;
  const char *p;
  char *end;

  p = _dbus_string_get_const_data_len (str, start,
                                       _dbus_string_get_length (str) - start);

  end = NULL;
  _dbus_set_errno_to_zero ();
  v = strtoul (p, &end, 0);
  if (end == NULL || end == p || errno != 0)
    return FALSE;

  if (value_return)
    *value_return = v;
  if (end_return)
    *end_return = start + (end - p);

  return TRUE;
}

#ifdef DBUS_BUILD_TESTS
static dbus_bool_t
ascii_isspace (char c)
{
  return (c == ' ' ||
          c == '\f' ||
          c == '\n' ||
          c == '\r' ||
          c == '\t' ||
          c == '\v');
}
#endif /* DBUS_BUILD_TESTS */

#ifdef DBUS_BUILD_TESTS
static dbus_bool_t
ascii_isdigit (char c)
{
  return c >= '0' && c <= '9';
}
#endif /* DBUS_BUILD_TESTS */

#ifdef DBUS_BUILD_TESTS
static dbus_bool_t
ascii_isxdigit (char c)
{
  return (ascii_isdigit (c) ||
          (c >= 'a' && c <= 'f') ||
          (c >= 'A' && c <= 'F'));
}
#endif /* DBUS_BUILD_TESTS */

#ifdef DBUS_BUILD_TESTS
/* Calls strtod in a locale-independent fashion, by looking at
 * the locale data and patching the decimal comma to a point.
 *
 * Relicensed from glib.
 */
static double
ascii_strtod (const char *nptr,
              char      **endptr)
{
  /* FIXME: The Win32 C library's strtod() doesn't handle hex.
   * Presumably many Unixes don't either.
   */

  char *fail_pos;
  double val;
  struct lconv *locale_data;
  const char *decimal_point;
  int decimal_point_len;
  const char *p, *decimal_point_pos;
  const char *end = NULL; /* Silence gcc */

  fail_pos = NULL;

#if HAVE_LOCALECONV
  locale_data = localeconv ();
  decimal_point = locale_data->decimal_point;
#else
  decimal_point = ".";
#endif

  decimal_point_len = strlen (decimal_point);
  _dbus_assert (decimal_point_len != 0);
  
  decimal_point_pos = NULL;
  if (decimal_point[0] != '.' ||
      decimal_point[1] != 0)
    {
      p = nptr;
      /* Skip leading space */
      while (ascii_isspace (*p))
        p++;
      
      /* Skip leading optional sign */
      if (*p == '+' || *p == '-')
        p++;
      
      if (p[0] == '0' &&
          (p[1] == 'x' || p[1] == 'X'))
        {
          p += 2;
          /* HEX - find the (optional) decimal point */
          
          while (ascii_isxdigit (*p))
            p++;
          
          if (*p == '.')
            {
              decimal_point_pos = p++;
              
              while (ascii_isxdigit (*p))
                p++;
              
              if (*p == 'p' || *p == 'P')
                p++;
              if (*p == '+' || *p == '-')
                p++;
              while (ascii_isdigit (*p))
                p++;
              end = p;
            }
        }
      else
        {
          while (ascii_isdigit (*p))
            p++;
          
          if (*p == '.')
            {
              decimal_point_pos = p++;
              
              while (ascii_isdigit (*p))
                p++;
              
              if (*p == 'e' || *p == 'E')
                p++;
              if (*p == '+' || *p == '-')
                p++;
              while (ascii_isdigit (*p))
                p++;
              end = p;
            }
        }
      /* For the other cases, we need not convert the decimal point */
    }

  /* Set errno to zero, so that we can distinguish zero results
     and underflows */
  _dbus_set_errno_to_zero ();
  
  if (decimal_point_pos)
    {
      char *copy, *c;

      /* We need to convert the '.' to the locale specific decimal point */
      copy = dbus_malloc (end - nptr + 1 + decimal_point_len);
      
      c = copy;
      memcpy (c, nptr, decimal_point_pos - nptr);
      c += decimal_point_pos - nptr;
      memcpy (c, decimal_point, decimal_point_len);
      c += decimal_point_len;
      memcpy (c, decimal_point_pos + 1, end - (decimal_point_pos + 1));
      c += end - (decimal_point_pos + 1);
      *c = 0;

      val = strtod (copy, &fail_pos);

      if (fail_pos)
        {
          if (fail_pos > decimal_point_pos)
            fail_pos = (char *)nptr + (fail_pos - copy) - (decimal_point_len - 1);
          else
            fail_pos = (char *)nptr + (fail_pos - copy);
        }
      
      dbus_free (copy);
          
    }
  else
    val = strtod (nptr, &fail_pos);

  if (endptr)
    *endptr = fail_pos;
  
  return val;
}
#endif /* DBUS_BUILD_TESTS */

#ifdef DBUS_BUILD_TESTS

dbus_bool_t
_dbus_string_parse_double (const DBusString *str,
                           int               start,
                           double           *value_return,
                           int              *end_return)
{
  double v;
  const char *p;
  char *end;

  p = _dbus_string_get_const_data_len (str, start,
                                       _dbus_string_get_length (str) - start);

  /* parsing hex works on linux but isn't portable, so intercept it
   * here to get uniform behavior.
   */
  if (p[0] == '0' && (p[1] == 'x' || p[1] == 'X'))
    return FALSE;
  
  end = NULL;
  _dbus_set_errno_to_zero ();
  v = ascii_strtod (p, &end);
  if (end == NULL || end == p || errno != 0)
    return FALSE;

  if (value_return)
    *value_return = v;
  if (end_return)
    *end_return = start + (end - p);

  return TRUE;
}
#endif /* DBUS_BUILD_TESTS */
 /* DBusString group */

void
_dbus_generate_pseudorandom_bytes_buffer (char *buffer,
                                          int   n_bytes)
{
  long tv_usec;
  int i;
  
  /* fall back to pseudorandom */
  _dbus_verbose ("Falling back to pseudorandom for %d bytes\n",
                 n_bytes);
  
  _dbus_get_current_time (NULL, &tv_usec);
  srand (tv_usec);
  
  i = 0;
  while (i < n_bytes)
    {
      double r;
      unsigned int b;
          
      r = rand ();
      b = (r / (double) RAND_MAX) * 255.0;

      buffer[i] = b;

      ++i;
    }
}

void
_dbus_generate_random_bytes_buffer (char *buffer,
                                    int   n_bytes)
{
  DBusString str;

  if (!_dbus_string_init (&str))
    {
      _dbus_generate_pseudorandom_bytes_buffer (buffer, n_bytes);
      return;
    }

  if (!_dbus_generate_random_bytes (&str, n_bytes))
    {
      _dbus_string_free (&str);
      _dbus_generate_pseudorandom_bytes_buffer (buffer, n_bytes);
      return;
    }

  _dbus_string_copy_to_buffer (&str, buffer, n_bytes);

  _dbus_string_free (&str);
}

dbus_bool_t
_dbus_generate_random_ascii (DBusString *str,
                             int         n_bytes)
{
  static const char letters[] =
    "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789abcdefghijklmnopqrstuvwxyz";
  int i;
  int len;
  
  if (!_dbus_generate_random_bytes (str, n_bytes))
    return FALSE;
  
  len = _dbus_string_get_length (str);
  i = len - n_bytes;
  while (i < len)
    {
      _dbus_string_set_byte (str, i,
                             letters[_dbus_string_get_byte (str, i) %
                                     (sizeof (letters) - 1)]);

      ++i;
    }

  _dbus_assert (_dbus_string_validate_ascii (str, len - n_bytes,
                                             n_bytes));

  return TRUE;
}

const char*
_dbus_error_from_errno (int error_number)
{
  switch (error_number)
    {
    case 0:
      return DBUS_ERROR_FAILED;
      
#ifdef EPROTONOSUPPORT
    case EPROTONOSUPPORT:
      return DBUS_ERROR_NOT_SUPPORTED;
#endif
#ifdef WSAEPROTONOSUPPORT
    case WSAEPROTONOSUPPORT:
      return DBUS_ERROR_NOT_SUPPORTED;
#endif
#ifdef EAFNOSUPPORT
    case EAFNOSUPPORT:
      return DBUS_ERROR_NOT_SUPPORTED;
#endif
#ifdef WSAEAFNOSUPPORT
    case WSAEAFNOSUPPORT:
      return DBUS_ERROR_NOT_SUPPORTED;
#endif
#ifdef ENFILE
    case ENFILE:
      return DBUS_ERROR_LIMITS_EXCEEDED; /* kernel out of memory */
#endif
#ifdef EMFILE
    case EMFILE:
      return DBUS_ERROR_LIMITS_EXCEEDED;
#endif
#ifdef EACCES
    case EACCES:
      return DBUS_ERROR_ACCESS_DENIED;
#endif
#ifdef EPERM
    case EPERM:
      return DBUS_ERROR_ACCESS_DENIED;
#endif
#ifdef ENOBUFS
    case ENOBUFS:
      return DBUS_ERROR_NO_MEMORY;
#endif
#ifdef ENOMEM
    case ENOMEM:
      return DBUS_ERROR_NO_MEMORY;
#endif
#ifdef ECONNREFUSED
    case ECONNREFUSED:
      return DBUS_ERROR_NO_SERVER;
#endif
#ifdef WSAECONNREFUSED
    case WSAECONNREFUSED:
      return DBUS_ERROR_NO_SERVER;
#endif
#ifdef ETIMEDOUT
    case ETIMEDOUT:
      return DBUS_ERROR_TIMEOUT;
#endif
#ifdef WSAETIMEDOUT
    case WSAETIMEDOUT:
      return DBUS_ERROR_TIMEOUT;
#endif
#ifdef ENETUNREACH
    case ENETUNREACH:
      return DBUS_ERROR_NO_NETWORK;
#endif
#ifdef WSAENETUNREACH
    case WSAENETUNREACH:
      return DBUS_ERROR_NO_NETWORK;
#endif
#ifdef EADDRINUSE
    case EADDRINUSE:
      return DBUS_ERROR_ADDRESS_IN_USE;
#endif
#ifdef WSAEADDRINUSE
    case WSAEADDRINUSE:
      return DBUS_ERROR_ADDRESS_IN_USE;
#endif
#ifdef EEXIST
    case EEXIST:
      return DBUS_ERROR_FILE_EXISTS;
#endif
#ifdef ENOENT
    case ENOENT:
      return DBUS_ERROR_FILE_NOT_FOUND;
#endif
    }

  return DBUS_ERROR_FAILED;
}

const char*
_dbus_error_from_system_errno (void)
{
  return _dbus_error_from_errno (errno);
}

void
_dbus_set_errno_to_zero (void)
{
#ifdef DBUS_WINCE
  SetLastError (0);
#else
  errno = 0;
#endif
}

dbus_bool_t
_dbus_get_is_errno_nonzero (void)
{
  return errno != 0;
}

dbus_bool_t
_dbus_get_is_errno_enomem (void)
{
  return errno == ENOMEM;
}

dbus_bool_t
_dbus_get_is_errno_eintr (void)
{
  return errno == EINTR;
}

dbus_bool_t
_dbus_get_is_errno_epipe (void)
{
  return errno == EPIPE;
}

dbus_bool_t
_dbus_get_is_errno_etoomanyrefs (void)
{
#ifdef ETOOMANYREFS
  return errno == ETOOMANYREFS;
#else
  return FALSE;
#endif
}

const char*
_dbus_strerror_from_errno (void)
{
  return _dbus_strerror (errno);
}

/* tests in dbus-sysdeps-util.c */

---