bus signal_handler: don't use _dbus_warn, and don't pretend to be portable

_dbus_warn isn't async-signal-safe, so that's out. We can use write()
instead; it's POSIX but not ISO C, but then again, so are signals.
Accordingly, guard it with DBUS_UNIX.

dbus-sysdeps-util-win doesn't actually implement _dbus_set_signal_handler
anyway, so not compiling this code on non-Unix seems more honest.

Bug: https://bugs.freedesktop.org/show_bug.cgi?id=33336
Reviewed-by: Thiago Macieira <thiago@kde.org>
This commit is contained in:
Simon McVittie 2011-06-13 15:59:14 +01:00
parent 50c81a35a7
commit c7ef3ead55

View file

@ -35,6 +35,9 @@
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h> /* for write() and STDERR_FILENO */
#endif
#include "selinux.h"
static BusContext *context;
@ -45,6 +48,7 @@ static int reload_pipe[2];
static void close_reload_pipe (DBusWatch **);
#ifdef DBUS_UNIX
static void
signal_handler (int sig)
{
@ -69,14 +73,24 @@ signal_handler (int sig)
* reloaded while draining the pipe buffer, which is what we
* wanted. It's harmless that it will be reloaded fewer times than
* we asked for, since the reload is delayed anyway, so new changes
* will be picked up. */
_dbus_warn ("Unable to write to reload pipe.\n");
* will be picked up.
*
* We use write() because _dbus_warn uses vfprintf, which isn't
* async-signal-safe.
*
* This is necessarily Unix-specific, but so are POSIX signals,
* so... */
static const char message[] =
"Unable to write to reload pipe - buffer full?\n";
write (STDERR_FILENO, message, strlen (message));
}
}
break;
#endif
}
}
#endif /* DBUS_UNIX */
static void
usage (void)
@ -521,12 +535,17 @@ main (int argc, char **argv)
setup_reload_pipe (bus_context_get_loop (context));
#ifdef DBUS_UNIX
/* POSIX signals are Unix-specific, and _dbus_set_signal_handler is
* unimplemented (and probably unimplementable) on Windows, so there's
* no point in trying to make the handler portable to non-Unix. */
#ifdef SIGHUP
_dbus_set_signal_handler (SIGHUP, signal_handler);
#endif
#ifdef DBUS_BUS_ENABLE_DNOTIFY_ON_LINUX
_dbus_set_signal_handler (SIGIO, signal_handler);
#endif /* DBUS_BUS_ENABLE_DNOTIFY_ON_LINUX */
#endif /* DBUS_UNIX */
_dbus_verbose ("We are on D-Bus...\n");
_dbus_loop_run (bus_context_get_loop (context));