2006-10-01 Havoc Pennington <hp@redhat.com>

	* tools/dbus-launch.c (print_variables): if no syntax is given,
	don't print something that's sort-of-half-sh-syntax, just print
	a plain key-value pairs thing.

	* tools/dbus-launch-x11.c: use machine ID rather than hostname for
	the local machine representation (but still have the hostname in
	the display). Remove the hostname from the display if it is
	localhost. Change session files to be named
	~/.dbus/session-bus/machine-display. Change X atoms to be
	underscore-prefixed so nobody whines about ICCCM compliance.
	Otherwise name them the same as the env variables.
	Change session file format to include key-value pairs and an
	explanatory comment. Keys are the same as the env variables.
	(set_address_in_x11): X property format can't depend on
	sizeof(pid_t) on a particular machine, fix to always be 32 bits

	* tools/dbus-launch.c: make --autolaunch take a machine id
	argument. If --autolaunch is used with a program to run, complain
	for now (but add a FIXME). Also, don't look for existing bus if
	there's a program to run (but add a FIXME).

	* dbus/dbus-sysdeps-unix.c (_dbus_get_autolaunch_address): pass
	machine uuid to dbus-launch (avoids linking dbus-launch to libdbus
	just to get this, and avoids duplicating uuid-reading code).

	* tools/dbus-launch.1: clarify various things

1 files changed, 140 insertions, 68 deletions

diff --git a/tools/dbus-launch-x11.c b/tools/dbus-launch-x11.c
index 67aef04d..f0588ad8 100644
--- a/tools/dbus-launch-x11.c
+++ b/tools/dbus-launch-x11.c
@@ -24,6 +24,8 @@
 
 #ifdef DBUS_BUILD_X11
 #include <stdlib.h>
+#include <sys/types.h>
+#include <sys/stat.h>
 #include <unistd.h>
 #include <fcntl.h>
 #include <errno.h>
@@ -46,39 +48,53 @@ x_io_error_handler (Display *xdisplay)
   return 0;
 }
 
-static char *
-get_local_hostname (void)
+static void
+remove_prefix (char *s,
+               char *prefix)
 {
-  static const int increment = 128;
-  static char *cache = NULL;
-  char *buffer = NULL;
-  int size = 0;
+  int plen;
+
+  plen = strlen (prefix);
 
-  while (cache == NULL)
+  if (strncmp (s, prefix, plen) == 0)
     {
-      size += increment;
-      buffer = realloc (buffer, size);
-      if (buffer == NULL)
-        return NULL;            /* out of memory */
+      memmove (s, s + plen, strlen (s) - plen + 1);
+    }
+}
 
-      if (gethostname (buffer, size - 1) == -1 &&
-          errno != ENAMETOOLONG)
-        return NULL;
+static const char*
+get_homedir (void)
+{
+  const char *home;
+  
+  home = getenv ("HOME");
+  if (home == NULL)
+    {
+      /* try from the user database */
+      struct passwd *user = getpwuid (getuid());
+      if (user != NULL)
+        home = user->pw_dir;
+    }
 
-      buffer[size - 1] = '\0';  /* to make sure */
-      cache = buffer;
+  if (home == NULL)
+    {
+      fprintf (stderr, "Can't get user home directory\n");
+      exit (1);
     }
 
-  return cache;
+  return home;
 }
 
+#define DBUS_DIR ".dbus"
+#define DBUS_SESSION_BUS_DIR "session-bus"
+
 static char *
 get_session_file (void)
 {
-  static const char prefix[] = "/.dbus-session-file_";
-  char *hostname;
+  static const char prefix[] = "/" DBUS_DIR "/" DBUS_SESSION_BUS_DIR "/";
+  const char *machine;
+  const char *home;
   char *display;
-  char *home;
   char *result;
   char *p;
 
@@ -92,43 +108,46 @@ get_session_file (void)
   /* remove the screen part of the display name */
   p = strrchr (display, ':');
   if (p != NULL)
-    for ( ; *p; ++p)
-      if (*p == '.')
+    {
+      for ( ; *p; ++p)
         {
-          *p = '\0';
-          break;
+          if (*p == '.')
+            {
+              *p = '\0';
+              break;
+            }
         }
-
-  /* replace the : in the display with _ */
-  for (p = display; *p; ++p)
-    if (*p == ':')
-      *p = '_';
-
-  hostname = get_local_hostname ();
-  if (hostname == NULL)
-    {
-      /* out of memory */
-      free (display);
-      return NULL;
     }
 
-  home = getenv ("HOME");
-  if (home == NULL)
+  /* Note that we leave the hostname in the display most of the
+   * time. The idea is that we want to be per-(machine,display,user)
+   * triplet to be extra-sure we get a bus we can connect to. Ideally
+   * we'd recognize when the hostname matches the machine we're on in
+   * all cases; we do try to drop localhost and localhost.localdomain
+   * as a special common case so that alternate spellings of DISPLAY
+   * don't result in extra bus instances.
+   *
+   * We also kill the ":" if there's nothing in front of it. This
+   * avoids an ugly double underscore in the filename.
+   */
+  remove_prefix (display, "localhost.localdomain:");
+  remove_prefix (display, "localhost:");
+  remove_prefix (display, ":");
+
+  /* replace the : in the display with _ if the : is still there.
+   * use _ instead of - since it can't be in hostnames.
+   */
+  for (p = display; *p; ++p)
     {
-      /* try from the user database */
-      struct passwd *user = getpwuid (getuid());
-      if (user == NULL)
-        {
-          verbose ("X11 integration disabled because the home directory"
-                   " could not be determined\n");
-          free (display);
-          return NULL;
-        }
-
-      home = user->pw_dir;
+      if (*p == ':')
+        *p = '_';
     }
+  
+  machine = get_machine_uuid ();
 
-  result = malloc (strlen (home) + strlen (prefix) + strlen (hostname) +
+  home = get_homedir ();
+  
+  result = malloc (strlen (home) + strlen (prefix) + strlen (machine) +
                    strlen (display) + 2);
   if (result == NULL)
     {
@@ -139,8 +158,8 @@ get_session_file (void)
 
   strcpy (result, home);
   strcat (result, prefix);
-  strcat (result, hostname);
-  strcat (result, "_");
+  strcat (result, machine);
+  strcat (result, "-");
   strcat (result, display);
   free (display);
 
@@ -148,6 +167,46 @@ get_session_file (void)
   return result;
 }
 
+static void
+ensure_session_directory (void)
+{
+  const char *home;
+  char *dir;
+  
+  home = get_homedir ();
+
+  /* be sure we have space for / and nul */
+  dir = malloc (strlen (home) + strlen (DBUS_DIR) + strlen (DBUS_SESSION_BUS_DIR) + 3);
+  if (dir == NULL)
+    {
+      fprintf (stderr, "no memory\n");
+      exit (1);
+    }
+  
+  strcpy (dir, home);
+  strcat (dir, "/");
+  strcat (dir, DBUS_DIR);
+
+  if (mkdir (dir, 0700) < 0)
+    {
+      /* only print a warning here, writing the session file itself will fail later */
+      if (errno != EEXIST)
+        fprintf (stderr, "Unable to create %s\n", dir);
+    }
+
+  strcat (dir, "/");
+  strcat (dir, DBUS_SESSION_BUS_DIR);
+
+  if (mkdir (dir, 0700) < 0)
+    {
+      /* only print a warning here, writing the session file itself will fail later */
+      if (errno != EEXIST)
+        fprintf (stderr, "Unable to create %s\n", dir);
+    }
+  
+  free (dir);
+}
+
 static Display *
 open_x11 (void)
 {
@@ -166,12 +225,12 @@ open_x11 (void)
 static int
 init_x_atoms (Display *display)
 {
-  static const char selection_prefix[] = "DBUS_SESSION_SELECTION_";
-  static const char address_prefix[] = "DBUS_SESSION_ADDRESS";
-  static const char pid_prefix[] = "DBUS_SESSION_PID";
+  static const char selection_prefix[] = "_DBUS_SESSION_BUS_SELECTION_";
+  static const char address_prefix[] = "_DBUS_SESSION_BUS_ADDRESS";
+  static const char pid_prefix[] = "_DBUS_SESSION_BUS_PID";
   static int init = FALSE;
   char *atom_name;
-  char *hostname;
+  const char *machine;
   char *user_name;
   struct passwd *user;
 
@@ -186,15 +245,9 @@ init_x_atoms (Display *display)
     }
   user_name = xstrdup(user->pw_name);
 
-  hostname = get_local_hostname ();
-  if (hostname == NULL)
-    {
-      verbose ("Could not create X11 atoms; aborting X11 integration.\n");
-      free (user_name);
-      return FALSE;
-    }
+  machine = get_machine_uuid ();
 
-  atom_name = malloc (strlen (hostname) + strlen (user_name) + 2 +
+  atom_name = malloc (strlen (machine) + strlen (user_name) + 2 +
                       MAX (strlen (selection_prefix),
                            MAX (strlen (address_prefix),
                                 strlen (pid_prefix))));
@@ -209,7 +262,7 @@ init_x_atoms (Display *display)
   strcpy (atom_name, selection_prefix);
   strcat (atom_name, user_name);
   strcat (atom_name, "_");
-  strcat (atom_name, hostname);
+  strcat (atom_name, machine);
   selection_atom = XInternAtom (display, atom_name, FALSE);
 
   /* create the address property atom */
@@ -285,7 +338,8 @@ set_address_in_x11(char *address, pid_t pid)
 {
   char *current_address;
   Window wid;
-
+  int pid32;
+  
   /* lock the X11 display to make sure we're doing this atomically */
   XGrabServer (xdisplay);
 
@@ -313,8 +367,14 @@ set_address_in_x11(char *address, pid_t pid)
   /* Save the property in the window */
   XChangeProperty (xdisplay, wid, address_atom, XA_STRING, 8, PropModeReplace,
                    (unsigned char *)address, strlen (address));
+  pid32 = pid;
+  if (sizeof(pid32) != 4)
+    {
+      fprintf (stderr, "int is not 32 bits!\n");
+      exit (1);
+    }
   XChangeProperty (xdisplay, wid, pid_atom, XA_CARDINAL, 32, PropModeReplace,
-                   (unsigned char *)&pid, sizeof(pid) / 4);
+                   (unsigned char *)&pid32, 1);
 
   /* Now grab the selection */
   XSetSelectionOwner (xdisplay, selection_atom, wid, CurrentTime);
@@ -337,6 +397,7 @@ set_address_in_file (char *address, pid_t pid, Window wid)
   char *session_file;
   FILE *f;
 
+  ensure_session_directory ();
   session_file = get_session_file();
   if (session_file == NULL)
     return FALSE;
@@ -344,7 +405,18 @@ set_address_in_file (char *address, pid_t pid, Window wid)
   f = fopen (session_file, "w");
   if (f == NULL)
     return FALSE;               /* some kind of error */
-  fprintf (f, "%s\n%ld\n%ld\n", address, (long)pid, (long)wid);
+  fprintf (f,
+           "# This file allows processes on the machine with id %s using \n"
+           "# display %s to find the D-Bus session bus with the below address.\n"
+           "# If the DBUS_SESSION_BUS_ADDRESS environment variable is set, it will\n"
+           "# be used rather than this file.\n"
+           "# See \"man dbus-launch\" for more details.\n"
+           "DBUS_SESSION_BUS_ADDRESS=%s\n"
+           "DBUS_SESSION_BUS_PID=%ld\n"
+           "DBUS_SESSION_BUS_WINDOWID=%ld\n",
+           get_machine_uuid (),
+           getenv ("DISPLAY"),
+           address, (long)pid, (long)wid);
 
   fclose (f);
   free (session_file);