path: root/gui/gdmcomm.c

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*-
 *
 *    GDMcommunication routines
 *    (c)2001 Queen of England, (c)2002,2003 George Lebl
 *
 *    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., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */

#include "config.h"
#include <glib/gi18n.h>
#include <gtk/gtk.h>
#include <gdk/gdkx.h>
#include <X11/Xauth.h>

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <stdio.h>
#include <sys/types.h>
#include <signal.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/un.h>
#include <errno.h>

#include "gdm.h"
#include "gdmcommon.h"
#include "gdmcomm.h"
#include "gdmconfig.h"

#include "gdm-common.h"
#include "gdm-socket-protocol.h"
#include "gdm-daemon-config-keys.h"

static gboolean bulk_acs = FALSE;
static gboolean quiet    = FALSE;
static int      num_cmds = 0;

/*
 * Normally errors are printed.  Setting quiet to TRUE turns off
 * display of error messages.
 */
void
gdmcomm_set_quiet_errors (gboolean enable)
{
	quiet = enable;
}

static char *
do_command (int fd, const char *command, gboolean get_response)
{
	GString *str;
	char buf[1];
	char *cstr;
	int ret;
#ifndef MSG_NOSIGNAL
	void (*old_handler)(int);
#endif

        gdm_common_debug ("Sending command: '%s'", command);

	cstr = g_strdup_printf ("%s\n", command);

#ifdef MSG_NOSIGNAL
	ret = send (fd, cstr, strlen (cstr), MSG_NOSIGNAL);
#else
	old_handler = signal (SIGPIPE, SIG_IGN);
	ret = send (fd, cstr, strlen (cstr), 0);
	signal (SIGPIPE, old_handler);
#endif
	g_free (cstr);

	num_cmds++;

	if (ret < 0) {
		if ( !quiet)
			gdm_common_debug ("Command failed, no data returned");
		return NULL;
	}

	/* No need to print debug, this is only used when closing */
	if ( ! get_response)
		return NULL;

	str = g_string_new (NULL);
	while (read (fd, buf, 1) == 1 &&
	       buf[0] != '\n') {
		g_string_append_c (str, buf[0]);
	}

        gdm_common_debug ("  Got response: '%s'", str->str);

	cstr = str->str;
	g_string_free (str, FALSE);

	/*
	 * If string is empty, then the daemon likely closed the connection 
	 * because of too many subconnections.  At any rate the daemon should
	 * not return an empty string.  All return values should start with
	 * "OK" or "ERROR".  Daemon should never complain about too many
	 * messages since the slave keeps track of the number of commands sent
	 * and should not send too many, but it does not hurt to check and
	 * manage it if it somehow happens.  In either case return NULL
	 * instead so the caller can try again.
	 */
	if (ve_string_empty (cstr) ||
	    strcmp (ve_sure_string (cstr), "ERROR 200 Too many messages") == 0) {
		if ( !quiet)
			gdm_common_debug ("Command failed, daemon busy.");
		g_free (cstr);
		return NULL;
	}

	return cstr;
}

static gboolean
version_ok_p (const char *version, const char *min_version)
{
	int a = 0, b = 0, c = 0, d = 0;
	int mina = 0, minb = 0, minc = 0, mind = 0;

	/* Note that if some fields in the version don't exist, then
	 * we don't mind, they are zero */
	sscanf (version, "%d.%d.%d.%d", &a, &b, &c, &d);
	sscanf (min_version, "%d.%d.%d.%d", &mina, &minb, &minc, &mind);

	if ((a > mina) ||
	    (a == mina && b > minb) ||
	    (a == mina && b == minb && c > minc) ||
	    (a == mina && b == minb && c == minc && d >= mind))
		return TRUE;
	else
		return FALSE;
}

static gboolean allow_sleep          = TRUE;
static gboolean did_sleep_on_failure = FALSE;
static int comm_fd                   = 0;

static char *
gdmcomm_call_gdm_real (const char *command,
		       const char *auth_cookie,
		       const char *min_version,
		       int tries,
		       int try_start)
{
	char *ret;

	/*
         * If already sent the max number of commands, close the connection
         * and reopen.  Subtract 1 to allow the "CLOSE" to get through.
         */
	if (num_cmds == (GDM_SUP_MAX_MESSAGES - 1)) {
		gdm_common_debug ("  Closing and reopening connection.");
		do_command (comm_fd, GDM_SUP_CLOSE, FALSE);
		VE_IGNORE_EINTR (close (comm_fd));
		comm_fd  = 0;
		num_cmds = 0;
	}

	if (tries <= 0) {
		if ( !quiet)
			gdm_common_debug ("  Command failed %d times, aborting.", try_start);
		return NULL;
	}

	if (!quiet && tries != try_start) {
		gdm_common_debug ("  Trying failed command again.  Try %d of %d.",
				  (try_start - tries + 1), try_start);
	}

	if (comm_fd <= 0) {
		struct sockaddr_un addr;
		strcpy (addr.sun_path, GDM_SUP_SOCKET);
		addr.sun_family = AF_UNIX;
		comm_fd = socket (AF_UNIX, SOCK_STREAM, 0);
		if (comm_fd < 0) {
			if ( !quiet)
				gdm_common_debug ("  Failed to open socket");

			return gdmcomm_call_gdm_real (command, auth_cookie, min_version, tries - 1, try_start);
		}

		if (connect (comm_fd, (struct sockaddr *)&addr, sizeof (addr)) < 0) {


			/*
			 * If there is a failure on connect, there are probably
                         * other clients fighting for the connection, so sleep
                         * for 1 second before retry to avoid failing over and
                         * over in a tight loop.
                         *
                         * Only do this if allow_sleep is true.  allow_sleep
                         * will get set to FALSE if the first call to this 
                         * function fails all retries.
			 */
			if (allow_sleep == TRUE) {

				did_sleep_on_failure = TRUE;

				/*
				 * Only actualy sleep if we are going to try
				 * again.
				 */
				if (tries > 1) {
					if ( !quiet)
						gdm_common_debug ("  Failed to connect to socket, sleep 1 second and retry");
					sleep (1);
				}
			} else {
				if ( !quiet)
					gdm_common_debug ("  Failed to connect to socket, not sleeping");
			}
			VE_IGNORE_EINTR (close (comm_fd));
			comm_fd = 0;
			return gdmcomm_call_gdm_real (command, auth_cookie,
						      min_version, tries - 1, try_start);
		}

		/*
                 * If we get this far, then even if we did sleep in the past,
		 * we did get a connection, so no need to prevent future
		 * sleeps if required.
                 */
		allow_sleep          = TRUE;
                did_sleep_on_failure = FALSE;

		/* Version check first - only check first time */
		ret = do_command (comm_fd, GDM_SUP_VERSION, TRUE);
		if (ret == NULL) {
			if ( !quiet)
				gdm_common_debug ("  Version check failed");
			VE_IGNORE_EINTR (close (comm_fd));
			comm_fd = 0;
			return gdmcomm_call_gdm_real (command, auth_cookie,
						      min_version, tries - 1, try_start);
		}
		if (strncmp (ret, "GDM ", strlen ("GDM ")) != 0) {
			if ( !quiet)
				gdm_common_debug ("  Version check failed, bad name");

			g_free (ret);
			do_command (comm_fd, GDM_SUP_CLOSE, FALSE);
			VE_IGNORE_EINTR (close (comm_fd));
			comm_fd = 0;
			return NULL;
		}
		if ( ! version_ok_p (&ret[4], min_version)) {
			if ( !quiet)
				gdm_common_debug ("  Version check failed, bad version");
			g_free (ret);
			do_command (comm_fd, GDM_SUP_CLOSE, FALSE);
			VE_IGNORE_EINTR (close (comm_fd));
			comm_fd = 0;
			return NULL;
		}
		g_free (ret);
	}

	/* require authentication */
	if (auth_cookie != NULL)  {
		char *auth_cmd = g_strdup_printf
			(GDM_SUP_AUTH_LOCAL " %s", auth_cookie);
		ret = do_command (comm_fd, auth_cmd, TRUE);
		g_free (auth_cmd);
		if (ret == NULL) {
			VE_IGNORE_EINTR (close (comm_fd));
			comm_fd = 0;
			return gdmcomm_call_gdm_real (command, auth_cookie,
						      min_version, tries - 1, try_start);
		}
		/* not auth'ed */
		if (strcmp (ve_sure_string (ret), "OK") != 0) {
			if ( !quiet)
				gdm_common_debug ("  Error, auth check failed");
			do_command (comm_fd, GDM_SUP_CLOSE, FALSE);
			VE_IGNORE_EINTR (close (comm_fd));
			comm_fd = 0;
			/* returns the error */
			return ret;
		}
		g_free (ret);
	}

	ret = do_command (comm_fd, command, TRUE);
	if (ret == NULL) {
		VE_IGNORE_EINTR (close (comm_fd));
		comm_fd = 0;
		return gdmcomm_call_gdm_real (command, auth_cookie,
					      min_version, tries - 1, try_start);
	}

	/*
	 * We want to leave the connection open if bulk_acs is set to
	 * true, so clients can read as much config data in one 
	 * sockets connection when it is set.  This requires that
	 * GDM client programs ensure that they call the bulk_start
	 * and bulk_stop functions around blocks of code that
	 * need to read data in bulk.  If a client reads config data
	 * outside of the bulk_start/stop functions, then this
	 * will just negatively affect performance since an additional
	 * socket will be opened to read that config data.
	 */
	if (bulk_acs == FALSE) {
		do_command (comm_fd, GDM_SUP_CLOSE, FALSE);
		VE_IGNORE_EINTR (close (comm_fd));
		comm_fd = 0;
	}

	return ret;
}

char *
gdmcomm_call_gdm (const char *command, const char * auth_cookie,
		  const char *min_version, int tries)
{

	char *retstr;

	retstr = gdmcomm_call_gdm_real (command, auth_cookie, min_version,
					tries, tries);

	/*
	 * Disallow sleeping on future calls if it failed to connect.
         * did_sleep_on_failure will only be TRUE if the function returned
	 * without ever connecting.
	 */
	if (did_sleep_on_failure == TRUE)
		allow_sleep = FALSE;

	return (retstr);
}

/**
 * gdmcomm_did_connection_fail
 *
 * If allow_sleep is TRUE, then connection was able to go through.
 * so the client can call this function after calling to see if
 * the failure was due to the connection being too busy.  This is
 * useful for gdmdynamic.
 */
gboolean
gdmcomm_did_connection_fail (void)
{
	return !allow_sleep;
}

void
gdmcomm_set_allow_sleep (gboolean val)
{
	allow_sleep = val;
}

void
gdmcomm_comm_bulk_start (void)
{
	bulk_acs = TRUE;
}

void
gdmcomm_comm_bulk_stop (void)
{
	/* Close the connection */
	if (comm_fd > 0) {
		do_command (comm_fd, GDM_SUP_CLOSE, FALSE);
		VE_IGNORE_EINTR (close (comm_fd));
	}
	comm_fd  = 0;
	num_cmds = 0;
	bulk_acs = FALSE;
}

const char *
gdmcomm_get_display (void)
{
	static char *display = NULL;

	if (display == NULL) {
		char *p;

		display = gdk_get_display ();
		if (display == NULL) {
			display = g_strdup (g_getenv ("DISPLAY"));
			if (display == NULL) /*eek!*/ {
				display = g_strdup (":0");
			}
		}

		/* whack screen part, GDM doesn't like those */
		p = strchr (display, '.');
		if (p != NULL)
			*p = '\0';
	}

	return display;
}

static char *
get_dispnum (void)
{
	static char *number = NULL;

	if (number == NULL) {
		char *p;
		number = g_strdup (gdmcomm_get_display ());

		/* whee! handles even DECnet */
		number = strchr (number, ':');
		if (number != NULL) {
			while (*number == ':') {
				number++;
			}
			p = strchr (number, '.');
			if (p != NULL)
				*p = '\0';
		} else {
			number = "0";
		}
	}

	return number;
}

/* This just gets a cookie of MIT-MAGIC-COOKIE-1 type */
char *
gdmcomm_get_a_cookie (gboolean binary)
{
	FILE *fp;
	char *number;
	char *cookie = NULL;
	Xauth *xau;

	VE_IGNORE_EINTR (fp = fopen (XauFileName (), "r"));
	if (fp == NULL) {
		return NULL;
	}

	number = get_dispnum ();

	cookie = NULL;

	while ((xau = XauReadAuth (fp)) != NULL) {
		/* Just find the FIRST magic cookie, that's what gdm uses */
		if (xau->number_length != strlen (number) ||
		    strncmp (xau->number, number, xau->number_length) != 0 ||
		    /* gdm sends MIT-MAGIC-COOKIE-1 cookies of length 16,
		     * so just do those */
		    xau->data_length != 16 ||
		    xau->name_length != strlen ("MIT-MAGIC-COOKIE-1") ||
		    strncmp (xau->name, "MIT-MAGIC-COOKIE-1",
			     xau->name_length) != 0) {
			XauDisposeAuth (xau);
			continue;
		}

		if (binary) {
			cookie = g_new0 (char, 16);
			memcpy (cookie, xau->data, 16);
		} else {
			int i;
			GString *str;

			str = g_string_new (NULL);

			for (i = 0; i < xau->data_length; i++) {
				g_string_append_printf
					(str, "%02x",
					 (guint)(guchar)xau->data[i]);
			}
			cookie = g_string_free (str, FALSE);
		}

		XauDisposeAuth (xau);

		break;
	}
	VE_IGNORE_EINTR (fclose (fp));

	return cookie;
}

char *
gdmcomm_get_auth_cookie (void)
{
	FILE *fp;
	char *number;
	static gboolean tried = FALSE;
	static char *cookie = NULL;
	Xauth *xau;

	if (tried)
		return cookie;

	VE_IGNORE_EINTR (fp = fopen (XauFileName (), "r"));
	if (fp == NULL) {
		cookie = NULL;
		tried = TRUE;
		return NULL;
	}

	number = get_dispnum ();

	cookie = NULL;

	while ((xau = XauReadAuth (fp)) != NULL) {
		char *cmd;
		char *ret;
		int i;
		char buffer[40 /* 2*16 == 32, so 40 is enough */];

		/* Only Family local things are considered, all console
		 * logins DO have this family (and even some local xdmcp
		 * logins, though those will not pass by gdm itself of
		 * course) */
		if (xau->family != FamilyLocal ||
		    xau->number_length != strlen (number) ||
		    strncmp (xau->number, number, xau->number_length) != 0 ||
		    /* gdm sends MIT-MAGIC-COOKIE-1 cookies of length 16,
		     * so just do those */
		    xau->data_length != 16 ||
		    xau->name_length != strlen ("MIT-MAGIC-COOKIE-1") ||
		    strncmp (xau->name, "MIT-MAGIC-COOKIE-1",
			     xau->name_length) != 0 ||
		    xau->data_length != 16) {
			XauDisposeAuth (xau);
			continue;
		}

		buffer[0] = '\0';
		for (i = 0; i < 16; i++) {
			char sub[3];
			g_snprintf (sub, sizeof (sub), "%02x",
				    (guint)(guchar)xau->data[i]);
			strcat (buffer, sub);
		}

		XauDisposeAuth (xau);

		cmd = g_strdup_printf (GDM_SUP_AUTH_LOCAL " %s", buffer);
		ret = gdmcomm_call_gdm (cmd, NULL /* auth cookie */, "2.2.4.0", 5);
		g_free (cmd);
		if (ret != NULL &&
		    strcmp (ve_sure_string (ret), "OK") == 0) {
			g_free (ret);
			cookie = g_strdup (buffer);
			break;
		}
		g_free (ret);
	}
	VE_IGNORE_EINTR (fclose (fp));

	tried = TRUE;
	return cookie;
}

static GtkWidget *
hig_dialog_new (GtkWindow      *parent,
		GtkDialogFlags flags,
		GtkMessageType type,
		GtkButtonsType buttons,
		const gchar    *primary_message,
		const gchar    *secondary_message)
{
	GtkWidget *dialog;

	dialog = gtk_message_dialog_new (GTK_WINDOW (parent),
		                         GTK_DIALOG_DESTROY_WITH_PARENT,
		                         type,
		                         buttons,
		                         "%s", primary_message);

	gtk_message_dialog_format_secondary_text (GTK_MESSAGE_DIALOG (dialog),
		                                  "%s", secondary_message);

	gtk_window_set_title (GTK_WINDOW (dialog), "");
	gtk_container_set_border_width (GTK_CONTAINER (dialog), 5);
	gtk_box_set_spacing (GTK_BOX (GTK_DIALOG (dialog)->vbox), 14);

  	return dialog;
}

gboolean
gdmcomm_check (gboolean show_dialog)
{
	GtkWidget *dialog;
	FILE *fp = NULL;
	long pid;
	const char *pidfile;
	struct stat s;
	int statret;

	pidfile = GDM_PID_FILE;

	pid = 0;
	if (pidfile != NULL)
		VE_IGNORE_EINTR (fp = fopen (pidfile, "r"));
	if (fp != NULL) {
		int r;
		VE_IGNORE_EINTR (r = fscanf (fp, "%ld", &pid));
		VE_IGNORE_EINTR (fclose (fp));
		if (r != 1)
			pid = 0;
	}

	errno = 0;
	if (pid <= 1 ||
	    (kill (pid, 0) < 0 &&
	     errno != EPERM)) {
		if (show_dialog) {
			dialog = hig_dialog_new (NULL /* parent */,
                                                 GTK_DIALOG_MODAL /* flags */,
                                                 GTK_MESSAGE_WARNING,
                                                 GTK_BUTTONS_OK,
                                                 _("GDM (GNOME Display Manager) is not "
                                                   "running."),
                                                 _("You might be using a different display "
                                                   "manager, such as KDM (KDE Display "
                                                   "Manager), CDE login (dtlogin), or xdm. "
                                                   "If you wish to use this feature, then "
                                                   "your system will need to be configured "
                                                   "to use GDM instead."));

			gtk_widget_show_all (dialog);
			gtk_dialog_run (GTK_DIALOG (dialog));
			gtk_widget_destroy (dialog);
		}
		return FALSE;
	}

	VE_IGNORE_EINTR (statret = g_stat (GDM_SUP_SOCKET, &s));
	if (statret < 0 ||
	    s.st_uid != 0 ||
	    g_access (GDM_SUP_SOCKET, R_OK|W_OK) != 0) {
		if (show_dialog) {
			dialog = hig_dialog_new (NULL /* parent */,
                                                 GTK_DIALOG_MODAL /* flags */,
                                                 GTK_MESSAGE_WARNING,
                                                 GTK_BUTTONS_OK,
                                                 _("Cannot communicate with GDM "
                                                   "(The GNOME Display Manager)"),
                                                 _("Perhaps you have an old version "
                                                   "of GDM running."));
			gtk_widget_show_all (dialog);
			gtk_dialog_run (GTK_DIALOG (dialog));
			gtk_widget_destroy (dialog);
		}
		return FALSE;
	}

	return TRUE;
}

const char *
gdmcomm_get_error_message (const char *ret, gboolean use_xnest)
{
	/* These need a bit more refinement */
	if (ret == NULL) {
		return _("Cannot communicate with GDM. Perhaps "
			 "you have an old version running.");
	} else if (strncmp (ret, "ERROR 0 ", strlen ("ERROR 0 ")) == 0) {
		return _("Cannot communicate with GDM. Perhaps "
			 "you have an old version running.");
	} else if (strncmp (ret, "ERROR 1 ", strlen ("ERROR 1 ")) == 0) {
		return _("The allowed limit of flexible X servers reached.");
	} else if (strncmp (ret, "ERROR 2 ", strlen ("ERROR 2 ")) == 0) {
		return _("There were errors trying to start the X server.");
	} else if (strncmp (ret, "ERROR 3 ", strlen ("ERROR 3 ")) == 0) {
		return _("The X server failed.  Perhaps it is not "
			 "configured well.");
	} else if (strncmp (ret, "ERROR 4 ", strlen ("ERROR 4 ")) == 0) {
		return _("Too many X sessions running.");
	} else if (strncmp (ret, "ERROR 5 ", strlen ("ERROR 5 ")) == 0) {
		return _("The nested X server cannot connect to your "
			 "current X server.  You may be missing an "
			 "X authorization file.");
	} else if (strncmp (ret, "ERROR 6 ", strlen ("ERROR 6 ")) == 0) {
		if (use_xnest)
			return _("The nested X server is not available, "
				 "or GDM is badly configured.\n"
				 "Please install the Xnest package in "
				 "order to use the nested login.");
		else
			return _("The X server is not available. "
				 "GDM may be misconfigured.");
	} else if (strncmp (ret, "ERROR 7 ", strlen ("ERROR 7 ")) == 0) {
		return _("Trying to set an unknown logout action, or trying "
			 "to set a logout action which is not available.");
	} else if (strncmp (ret, "ERROR 8 ", strlen ("ERROR 8 ")) == 0) {
		return _("Virtual terminals not supported.");
	} else if (strncmp (ret, "ERROR 9 ", strlen ("ERROR 9 ")) == 0) {
		return _("Trying to change to an invalid virtual terminal number.");
	} else if (strncmp (ret, "ERROR 50 ", strlen ("ERROR 50 ")) == 0) {
		return _("Trying to update an unsupported configuration key.");
	} else if (strncmp (ret, "ERROR 100 ", strlen ("ERROR 100 ")) == 0) {
		return _("You do not seem to have the authentication needed "
			 "for this operation.  Perhaps your .Xauthority "
			 "file is not set up correctly.");
	} else if (strncmp (ret, "ERROR 200 ", strlen ("ERROR 200 ")) == 0) {
		return _("Too many messages were sent to GDM and it hung up "
			 "on us.");
	} else {
		return _("Unknown error occurred.");
	}
}