static unsigned int
get_random_seed (void)
{
DBusString bytes;
unsigned int seed;
int fd;
const char *s;
seed = 0;
if (!_dbus_string_init (&bytes))
exit (1);
fd = open ("/dev/urandom", O_RDONLY);
if (fd < 0)
goto use_fallback;
if (_dbus_read (fd, &bytes, 4) != 4)
goto use_fallback;
close (fd);
s = _dbus_string_get_const_data (&bytes);
seed = * (unsigned int*) s;
goto out;
use_fallback:
{
long tv_usec;
fprintf (stderr, "could not open/read /dev/urandom, using current time for seed\n");
_dbus_get_current_time (NULL, &tv_usec);
seed = tv_usec;
}
out:
_dbus_string_free (&bytes);
return seed;
}
/**
* Get a printable string describing the command used to execute
* the process with pid. This string should only be used for
* informative purposes such as logging; it may not be trusted.
*
* The command is guaranteed to be printable ASCII and no longer
* than max_len.
*
* @param pid Process id
* @param str Append command to this string
* @param max_len Maximum length of returned command
* @param error return location for errors
* @returns #FALSE on error
*/
dbus_bool_t
_dbus_command_for_pid (unsigned long pid,
DBusString *str,
int max_len,
DBusError *error)
{
/* This is all Linux-specific for now */
DBusString path;
DBusString cmdline;
int fd;
if (!_dbus_string_init (&path))
{
_DBUS_SET_OOM (error);
return FALSE;
}
if (!_dbus_string_init (&cmdline))
{
_DBUS_SET_OOM (error);
_dbus_string_free (&path);
return FALSE;
}
if (!_dbus_string_append_printf (&path, "/proc/%ld/cmdline", pid))
goto oom;
fd = open (_dbus_string_get_const_data (&path), O_RDONLY);
if (fd < 0)
{
dbus_set_error (error,
_dbus_error_from_errno (errno),
"Failed to open \"%s\": %s",
_dbus_string_get_const_data (&path),
_dbus_strerror (errno));
goto fail;
}
if (!_dbus_read (fd, &cmdline, max_len))
{
dbus_set_error (error,
_dbus_error_from_errno (errno),
"Failed to read from \"%s\": %s",
_dbus_string_get_const_data (&path),
_dbus_strerror (errno));
goto fail;
}
if (!_dbus_close (fd, error))
goto fail;
string_squash_nonprintable (&cmdline);
if (!_dbus_string_copy (&cmdline, 0, str, _dbus_string_get_length (str)))
goto oom;
_dbus_string_free (&cmdline);
_dbus_string_free (&path);
return TRUE;
oom:
_DBUS_SET_OOM (error);
fail:
_dbus_string_free (&cmdline);
_dbus_string_free (&path);
return FALSE;
}
