X-Git-Url: http://git.maemo.org/git/?p=browser-switch;a=blobdiff_plain;f=launcher.c;h=f42e999d5333b23c781c65445511b4b2cf4c2ae2;hp=5a6b9517b8e111aa726253ee4b4a266c263c0157;hb=edc54287e04f78e16d546279ca5ed392f07151b4;hpb=4c3459d73a3e6a145230490af14dbba647fe4896

diff --git a/launcher.c b/launcher.c
index 5a6b951..f42e999 100644
--- a/launcher.c
+++ b/launcher.c
@@ -1,7 +1,7 @@
 /*
  * launcher.c -- functions for launching web browsers for browser-switchboard
  *
- * Copyright (C) 2009 Steven Luo
+ * Copyright (C) 2009-2010 Steven Luo
  * Derived from a Python implementation by Jason Simpson and Steven Luo
  *
  * This program is free software; you can redistribute it and/or
@@ -23,16 +23,56 @@
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
+#include <errno.h>
 #include <unistd.h>
 #include <sys/types.h>
 #include <sys/wait.h>
+#include <sys/stat.h>
+#include <fcntl.h>
 #include <dbus/dbus-glib.h>
 
+#ifdef FREMANTLE
+#include <dbus/dbus.h>
+#include <signal.h>
+#include <sys/ptrace.h>
+#include <sys/inotify.h>
+
+#define DEFAULT_HOMEDIR "/home/user"
+#define MICROB_PROFILE_DIR "/.mozilla/microb"
+#define MICROB_LOCKFILE "lock"
+#endif
+
 #include "browser-switchboard.h"
 #include "launcher.h"
 #include "dbus-server-bindings.h"
+#include "log.h"
+
+struct browser_launcher {
+	char *name;
+	void (*launcher)(struct swb_context *, char *);
+	char *other_browser_cmd;
+	char *binary;
+};
+
+#ifdef FREMANTLE
+static int microb_started = 0;
+#endif
+
+
+/* Close stdin/stdout/stderr and replace with /dev/null */
+static int close_stdio(void) {
+	int fd;
+
+	if ((fd = open("/dev/null", O_RDWR)) == -1)
+		return -1;
+
+	if (dup2(fd, 0) == -1 || dup2(fd, 1) == -1 || dup2(fd, 2) == -1)
+		return -1;
+
+	close(fd);
+	return 0;
+}
 
-#define LAUNCH_DEFAULT_BROWSER launch_tear
 
 static void launch_tear(struct swb_context *ctx, char *uri) {
 	int status;
@@ -43,61 +83,556 @@ static void launch_tear(struct swb_context *ctx, char *uri) {
 	if (!uri)
 		uri = "new_window";
 
-	printf("launch_tear with uri '%s'\n", uri);
+	log_msg("launch_tear with uri '%s'\n", uri);
 
+	/* We should be able to just call the D-Bus service to open Tear ...
+	   but if Tear's not open, that cuases D-Bus to start Tear and then
+	   pass it the OpenAddress call, which results in two browser windows.
+	   Properly fixing this probably requires Tear to provide a D-Bus
+	   method that opens an address in an existing window, but for now work
+	   around by just invoking Tear with exec() if it's not running. */
 	status = system("pidof tear > /dev/null");
-	if (!WIFEXITED(status))
-		exit(1);
-	if (!WEXITSTATUS(status)) {
-		if (!tear_proxy)
-			tear_proxy = dbus_g_proxy_new_for_name(ctx->session_bus,
-				       	"com.nokia.tear", "/com/nokia/tear",
-					"com.nokia.Tear");
-		dbus_g_proxy_call(tear_proxy, "OpenAddress", &error,
-				  G_TYPE_STRING, uri, G_TYPE_INVALID);
+	if (WIFEXITED(status) && !WEXITSTATUS(status)) {
+		if (!tear_proxy) {
+			if (!(tear_proxy = dbus_g_proxy_new_for_name(
+						ctx->session_bus,
+						"com.nokia.tear",
+						"/com/nokia/tear",
+						"com.nokia.Tear"))) {
+				log_msg("Failed to create proxy for com.nokia.Tear D-Bus interface\n");
+				exit(1);
+			}
+		}
+
+		if (!dbus_g_proxy_call(tear_proxy, "OpenAddress", &error,
+				       G_TYPE_STRING, uri, G_TYPE_INVALID,
+				       G_TYPE_INVALID)) {
+			log_msg("Opening window failed: %s\n", error->message);
+			exit(1);
+		}
 		if (!ctx->continuous_mode)
 			exit(0);
 	} else {
 		if (ctx->continuous_mode) {
 			if ((pid = fork()) != 0) {
 				/* Parent process or error in fork() */
-				printf("child: %d\n", (int)pid);
+				log_msg("child: %d\n", (int)pid);
 				return;
 			}
 			/* Child process */
 			setsid();
+			close_stdio();
 		}
 		execl("/usr/bin/tear", "/usr/bin/tear", uri, (char *)NULL);
 	}
 }
 
+
+#ifdef FREMANTLE
+/* Get a browserd PID from the corresponding Mozilla profile lockfile */
+static pid_t get_browserd_pid(const char *lockfile) {
+	char buf[256], *tmp;
+
+	/* The lockfile is a symlink pointing to "[ipaddr]:+[pid]", so read in
+	   the target of the symlink and parse it that way */
+	memset(buf, '\0', 256);
+	if (readlink(lockfile, buf, 255) == -1)
+		return -errno;
+	if (!(tmp = strstr(buf, ":+")))
+		return 0;
+	tmp += 2; /* Skip over the ":+" */
+
+	return atoi(tmp);
+}
+
+/* Check to see whether MicroB is ready to handle D-Bus requests yet
+   See the comments in microb_start_dbus_watch_* to understand how this
+   works. */
+static DBusHandlerResult check_microb_started(DBusConnection *connection,
+				     DBusMessage *message,
+				     void *user_data) {
+	DBusError error;
+	char *name, *old, *new;
+
+	log_msg("Checking to see if MicroB is ready\n");
+	dbus_error_init(&error);
+	if (!dbus_message_get_args(message, &error,
+				   DBUS_TYPE_STRING, &name,
+				   DBUS_TYPE_STRING, &old,
+				   DBUS_TYPE_STRING, &new,
+				   DBUS_TYPE_INVALID)) {
+		log_msg("%s\n", error.message);
+		dbus_error_free(&error);
+		return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
+	}
+	/* If new is not an empty string, then the name has been acquired, and
+	   MicroB should be ready to handle our request */
+	if (strlen(new) > 0) {
+		log_msg("MicroB ready\n");
+		microb_started = 1;
+	}
+
+	return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
+}
+
+/* Set up the D-Bus eavesdropping we'll use to watch for MicroB acquiring the
+   com.nokia.osso_browser D-Bus name.
+
+   Ideas for how to do this monitoring derived from the dbus-monitor code
+   (tools/dbus-monitor.c in the D-Bus codebase). */
+DBusConnection *microb_start_dbus_watch_init(void) {
+	DBusConnection *conn;
+	DBusError dbus_error;
+	DBusHandleMessageFunction filter_func = check_microb_started;
+
+	dbus_error_init(&dbus_error);
+
+	conn = dbus_bus_get_private(DBUS_BUS_SESSION, &dbus_error);
+	if (!conn) {
+		log_msg("Failed to open connection to session bus: %s\n",
+			dbus_error.message);
+		dbus_error_free(&dbus_error);
+		return NULL;
+	}
+
+	dbus_bus_add_match(conn,
+			   "type='signal',interface='org.freedesktop.DBus',member='NameOwnerChanged',arg0='com.nokia.osso_browser'",
+			   &dbus_error);
+	if (dbus_error_is_set(&dbus_error)) {
+		log_msg("Failed to set up watch for browser UI start: %s\n",
+			dbus_error.message);
+		dbus_error_free(&dbus_error);
+		return NULL;
+	}
+	if (!dbus_connection_add_filter(conn, filter_func, NULL, NULL)) {
+		log_msg("Failed to set up watch filter!\n");
+		return NULL;
+	}
+
+	return conn;
+}
+
+/* Wait for MicroB to acquire the com.nokia.osso_browser D-Bus name
+   Blocks until name is acquired, then returns */
+void microb_start_dbus_watch_wait(DBusConnection *conn) {
+	microb_started = 0;
+	log_msg("Waiting for MicroB to start\n");
+	while (!microb_started &&
+	       dbus_connection_read_write_dispatch(conn, -1));
+}
+
+/* Tear down the D-Bus watch for acquiring com.nokia.osso-browser */
+void microb_start_dbus_watch_remove(DBusConnection *conn) {
+	DBusError dbus_error;
+	DBusHandleMessageFunction filter_func = check_microb_started;
+
+	dbus_error_init(&dbus_error);
+
+	dbus_connection_remove_filter(conn, filter_func, NULL);
+	dbus_bus_remove_match(conn,
+			      "type='signal',interface='org.freedesktop.DBus',member='NameOwnerChanged',arg0='com.nokia.osso_browser'",
+			      &dbus_error);
+	if (dbus_error_is_set(&dbus_error))
+		/* Don't really care -- about to disconnect from the
+		   bus anyhow */
+		dbus_error_free(&dbus_error);
+	dbus_connection_close(conn);
+	dbus_connection_unref(conn);
+}
+
+/* Start a new MicroB browser process if one isn't already running */
+pid_t launch_microb_start_browser_process(DBusConnection *conn, int fd) {
+	pid_t pid;
+	int status;
+
+	status = system("pidof browser > /dev/null");
+	if (WIFEXITED(status) && !WEXITSTATUS(status)) {
+		/* MicroB browser already running */
+		return 0;
+	}
+
+	if ((pid = fork()) == -1) {
+		log_perror(errno, "fork");
+		return -1;
+	}
+
+	if (!pid) {
+		/* Child process */
+		dbus_connection_close(conn);
+		dbus_connection_unref(conn);
+		if (fd != -1)
+			close(fd);
+		close_stdio();
+
+		/* exec maemo-invoker directly instead of relying on the
+		   /usr/bin/browser symlink, since /usr/bin/browser may have
+		   been replaced with a shell script calling us via D-Bus */
+		/* Launch the browser in the background -- our parent will
+		   wait for it to claim the D-Bus name and then display the
+		   window using D-Bus */
+		execl("/usr/bin/maemo-invoker", "browser", (char *)NULL);
+
+		/* If we get here, exec() failed */
+		exit(1);
+	}
+
+	return pid;
+}
+
+/* Open a MicroB window using the D-Bus interface
+   It's assumed that we have already released the D-Bus name and that it's been
+   ensured that MicroB has acquired com.nokia.osso_browser (otherwise this will
+   cause D-Bus to try forever to launch another browser-switchboard) */
+
+#define LAUNCH_MICROB_BOOKMARK_WIN_OK 0x1
+
+int launch_microb_open_window(struct swb_context *ctx, char *uri,
+			      int flags) {
+	DBusGProxy *g_proxy;
+	GError *gerror = NULL;
+
+	g_proxy = dbus_g_proxy_new_for_name(ctx->session_bus,
+			"com.nokia.osso_browser",
+			"/com/nokia/osso_browser/request",
+			"com.nokia.osso_browser");
+	if (!g_proxy) {
+		log_msg("Couldn't get a com.nokia.osso_browser proxy\n");
+		return 0;
+	}
+
+	if (!strcmp(uri, "new_window")) {
+		if (flags & LAUNCH_MICROB_BOOKMARK_WIN_OK) {
+			if (!dbus_g_proxy_call(g_proxy, "top_application",
+					       &gerror, G_TYPE_INVALID,
+					       G_TYPE_INVALID)) {
+				log_msg("Opening window failed: %s\n",
+					gerror->message);
+				g_error_free(gerror);
+				return 0;
+			}
+
+			return 1;
+		} else {
+			/* Since we can't detect when the bookmark window
+			   closes, we'd have a corner case where, if the user
+			   just closes the bookmark window without opening any
+			   browser windows, we don't kill off MicroB or resume
+			   handling com.nokia.osso_browser */
+			uri = "about:blank";
+		}
+	}
+	if (!dbus_g_proxy_call(g_proxy, "load_url",
+			       &gerror,
+			       G_TYPE_STRING, uri,
+			       G_TYPE_INVALID,
+			       G_TYPE_INVALID)) {
+		log_msg("Opening window failed: %s\n", gerror->message);
+		g_error_free(gerror);
+		return 0;
+	}
+
+	g_object_unref(g_proxy);
+	return 1;
+}
+
+/* Launch Fremantle MicroB and kill it when the session is finished */
+void launch_microb_fremantle_with_kill(struct swb_context *ctx, char *uri) {
+	int status;
+	pid_t pid;
+	char *homedir, *microb_profile_dir, *microb_lockfile;
+	size_t len;
+	int fd, inot_wd;
+	DBusConnection *raw_connection;
+	int bytes_read;
+	char buf[256], *pos;
+	struct inotify_event *event;
+	pid_t browserd_pid, waited_pid;
+	struct sigaction act, oldact;
+	int ignore_sigstop;
+
+	/* Put together the path to the MicroB browserd lockfile */
+	if (!(homedir = getenv("HOME")))
+		homedir = DEFAULT_HOMEDIR;
+	len = strlen(homedir) + strlen(MICROB_PROFILE_DIR) + 1;
+	if (!(microb_profile_dir = calloc(len, sizeof(char)))) {
+		log_msg("calloc() failed\n");
+		exit(1);
+	}
+	snprintf(microb_profile_dir, len, "%s%s",
+		 homedir, MICROB_PROFILE_DIR);
+	len = strlen(homedir) + strlen(MICROB_PROFILE_DIR) +
+	      strlen("/") + strlen(MICROB_LOCKFILE) + 1;
+	if (!(microb_lockfile = calloc(len, sizeof(char)))) {
+		log_msg("calloc() failed\n");
+		exit(1);
+	}
+	snprintf(microb_lockfile, len, "%s%s/%s",
+		 homedir, MICROB_PROFILE_DIR, MICROB_LOCKFILE);
+
+	/* Watch for the creation of a MicroB browserd lockfile
+	   NB: The watch has to be set up here, before the browser
+	   is launched, to make sure there's no race between browserd
+	   starting and us creating the watch */
+	if ((fd = inotify_init()) == -1) {
+		log_perror(errno, "inotify_init");
+		exit(1);
+	}
+	if ((inot_wd = inotify_add_watch(fd, microb_profile_dir,
+					 IN_CREATE)) == -1) {
+		log_perror(errno, "inotify_add_watch");
+		exit(1);
+	}
+	free(microb_profile_dir);
+
+	/* Set up the D-Bus eavesdropping we'll use to watch for MicroB
+	   acquiring the com.nokia.osso_browser D-Bus name.  Again, this needs
+	   to happen before the browser is launched, so that there's no race
+	   between establishing the watch and browser startup. */
+	if (!(raw_connection = microb_start_dbus_watch_init())) {
+		exit(1);
+	}
+
+	/* Launch a MicroB browser process if it's not already running */
+	if ((pid = launch_microb_start_browser_process(raw_connection, fd)) < 0)
+		exit(1);
+
+	/* Release the osso_browser D-Bus name so that MicroB can take it */
+	dbus_release_osso_browser_name(ctx);
+
+	/* Wait for our child to start the browser UI process and
+	   for it to acquire the com.nokia.osso_browser D-Bus name,
+	   then make the appropriate method call to open the browser
+	   window. */
+	microb_start_dbus_watch_wait(raw_connection);
+	microb_start_dbus_watch_remove(raw_connection);
+	if (!launch_microb_open_window(ctx, uri, 0)) {
+		exit(1);
+	}
+
+	/* Workaround: the browser process we started is going to want
+	   to hang around forever, hogging the com.nokia.osso_browser
+	   D-Bus interface while at it.  To fix this, we notice that
+	   when the last browser window closes, the browser UI restarts
+	   its attached browserd process.  Get the browserd process's
+	   PID and use ptrace() to watch for process termination.
+
+	   This has the problem of not being able to detect whether
+	   the bookmark window is open and/or in use, but it's the best
+	   that I can think of.  Better suggestions would be greatly
+	   appreciated. */
+
+	if (!pid)
+		/* If we didn't start the MicroB browser process ourselves, try
+		   to get the PID of the browserd from the lockfile */
+		browserd_pid = get_browserd_pid(microb_lockfile);
+	else
+		browserd_pid = 0;
+
+	/* If getting the lockfile PID failed, or the lockfile PID doesn't
+	   exist, assume that we have a stale lockfile and wait for the new
+	   browserd lockfile to be created */
+	if (browserd_pid <= 0 || kill(browserd_pid, 0) == ESRCH) {
+		log_msg("Waiting for browserd lockfile to be created\n");
+		memset(buf, '\0', 256);
+		/* read() blocks until there are events to be read */
+		while ((bytes_read = read(fd, buf, 255)) > 0) {
+			pos = buf;
+			/* Loop until we see the event we're looking for
+			   or until all the events are processed */
+			while (pos && (pos-buf) < bytes_read) {
+				event = (struct inotify_event *)pos;
+				len = sizeof(struct inotify_event) + event->len;
+				if (!strcmp(MICROB_LOCKFILE, event->name)) {
+					/* Lockfile created */
+					pos = NULL;
+					break;
+				} else if ((pos-buf) + len < bytes_read)
+					/* More events to process */
+					pos += len;
+				else
+					/* All events processed */
+					break;
+			}
+			if (!pos)
+				/* Event found, stop looking */
+				break;
+			memset(buf, '\0', 256);
+		}
+
+		if ((browserd_pid = get_browserd_pid(microb_lockfile)) <= 0) {
+			if (browserd_pid == 0)
+				log_msg("Profile lockfile link lacks PID\n");
+			else
+				log_perror(-browserd_pid,
+					   "readlink() on lockfile failed");
+			exit(1);
+		}
+	}
+	inotify_rm_watch(fd, inot_wd);
+	close(fd);
+	free(microb_lockfile);
+
+	/* Wait for the browserd to close */
+	log_msg("Waiting for MicroB (browserd pid %d) to finish\n",
+		browserd_pid);
+	/* Clear any existing SIGCHLD handler to prevent interference
+	   with our wait() */
+	act.sa_handler = SIG_DFL;
+	act.sa_flags = 0;
+	sigemptyset(&(act.sa_mask));
+	if (sigaction(SIGCHLD, &act, &oldact) == -1) {
+		log_perror(errno, "clearing SIGCHLD handler failed");
+		exit(1);
+	}
+
+	/* Trace the browserd to get a close notification */
+	ignore_sigstop = 1;
+	if (ptrace(PTRACE_ATTACH, browserd_pid, NULL, NULL) == -1) {
+		log_perror(errno, "PTRACE_ATTACH");
+		exit(1);
+	}
+	ptrace(PTRACE_CONT, browserd_pid, NULL, NULL);
+	while ((waited_pid = wait(&status)) > 0) {
+		if (waited_pid != browserd_pid)
+			/* Not interested in other processes */
+			continue;
+		if (WIFEXITED(status) || WIFSIGNALED(status))
+			/* browserd exited */
+			break;
+		else if (WIFSTOPPED(status)) {
+			/* browserd was sent a signal
+			   We're responsible for making sure this signal gets
+			   delivered */
+			if (ignore_sigstop && WSTOPSIG(status) == SIGSTOP) {
+				/* Ignore the first SIGSTOP received
+				   This is raised for some reason immediately
+				   after we start tracing the process, and
+				   won't be followed by a SIGCONT at any point
+				 */
+				log_msg("Ignoring first SIGSTOP\n");
+				ptrace(PTRACE_CONT, browserd_pid, NULL, NULL);
+				ignore_sigstop = 0;
+				continue;
+			}
+			log_msg("Forwarding signal %d to browserd\n",
+				WSTOPSIG(status));
+			ptrace(PTRACE_CONT, browserd_pid, NULL,
+			       WSTOPSIG(status));
+		}
+	}
+
+	/* Kill off browser UI
+	   XXX: There is a race here with the restarting of the closed
+	   browserd; if that happens before we kill the browser UI, the newly
+	   started browserd may not close with the UI
+	   XXX: Hope we don't cause data loss here! */
+	log_msg("Killing MicroB\n");
+	if (pid > 0) {
+		kill(pid, SIGTERM);
+		waitpid(pid, &status, 0);
+	} else {
+		system("kill `pidof browser` > /dev/null 2>&1");
+	}
+
+	/* Restore old SIGCHLD handler */
+	if (sigaction(SIGCHLD, &oldact, NULL) == -1) {
+		log_perror(errno, "restoring old SIGCHLD handler failed");
+		exit(1);
+	}
+
+	dbus_request_osso_browser_name(ctx);
+}
+
+/* Launch a new window in Fremantle MicroB; don't kill the MicroB process
+   when the session is finished
+   This is designed to work with a prestarted MicroB process that runs
+   continuously in the background */
+void launch_microb_fremantle(struct swb_context *ctx, char *uri) {
+	DBusConnection *raw_connection;
+
+	/* Set up the D-Bus eavesdropping we'll use to watch for MicroB
+	   acquiring the com.nokia.osso_browser D-Bus name */
+	if (!(raw_connection = microb_start_dbus_watch_init())) {
+		exit(1);
+	}
+
+	/* Launch a MicroB browser process if it's not already running */
+	if (launch_microb_start_browser_process(raw_connection, -1) < 0)
+		exit(1);
+
+	/* Release the osso_browser D-Bus name so that MicroB can take it */
+	dbus_release_osso_browser_name(ctx);
+
+	/* Wait for MicroB to acquire com.nokia.osso_browser, then make the
+	   appropriate method call to open the browser window. */
+	microb_start_dbus_watch_wait(raw_connection);
+	microb_start_dbus_watch_remove(raw_connection);
+	if (!launch_microb_open_window(ctx, uri,
+				       LAUNCH_MICROB_BOOKMARK_WIN_OK)) {
+		exit(1);
+	}
+
+	/* Take back the osso_browser D-Bus name from MicroB */
+	dbus_request_osso_browser_name(ctx);
+}
+#endif /* FREMANTLE */
+
 void launch_microb(struct swb_context *ctx, char *uri) {
 	int kill_browserd = 0;
 	int status;
+#ifndef FREMANTLE
 	pid_t pid;
+#endif
 
 	if (!uri)
 		uri = "new_window";
 
-	status = system("pidof /usr/sbin/browserd > /dev/null");
-	if (!WIFEXITED(status))
-		exit(1);
-	if (WEXITSTATUS(status)) {
+	log_msg("launch_microb with uri '%s'\n", uri);
+
+	/* Launch browserd if it's not running */
+	status = system("pidof browserd > /dev/null");
+	if (WIFEXITED(status) && WEXITSTATUS(status)) {
 		kill_browserd = 1;
-		system("/usr/sbin/browserd -d");
+#ifdef FREMANTLE
+		system("/usr/sbin/browserd -d -b > /dev/null 2>&1");
+#else
+		system("/usr/sbin/browserd -d > /dev/null 2>&1");
+#endif
 	}
 
+#ifdef FREMANTLE
+	/* Do the insanity to launch Fremantle MicroB */
+	if ((ctx->default_browser_launcher == launch_microb &&
+	     ctx->autostart_microb) || ctx->autostart_microb == 1) {
+
+		/* If MicroB is set as the default browser, or if the user has
+		   configured MicroB to always be running, just send the
+		   running MicroB the request */
+		launch_microb_fremantle(ctx, uri);
+	} else {
+		/* Otherwise, launch MicroB and kill it when the user's
+		   MicroB session is done */
+		launch_microb_fremantle_with_kill(ctx, uri);
+	}
+#else /* !FREMANTLE */
+	/* Release the osso_browser D-Bus name so that MicroB can take it */
 	dbus_release_osso_browser_name(ctx);
 
 	if ((pid = fork()) == -1) {
-		perror("fork");
+		log_perror(errno, "fork");
 		exit(1);
 	}
+
 	if (pid > 0) {
 		/* Parent process */
 		waitpid(pid, &status, 0);
 	} else {
 		/* Child process */
+		close_stdio();
+
+		/* exec maemo-invoker directly instead of relying on the
+		   /usr/bin/browser symlink, since /usr/bin/browser may have
+		   been replaced with a shell script calling us via D-Bus */
 		if (!strcmp(uri, "new_window")) {
 			execl("/usr/bin/maemo-invoker",
 			      "browser", (char *)NULL);
@@ -107,13 +642,15 @@ void launch_microb(struct swb_context *ctx, char *uri) {
 		}
 	}
 
+	dbus_request_osso_browser_name(ctx);
+#endif /* FREMANTLE */
+
+	/* Kill off browserd if we started it */
 	if (kill_browserd)
-		system("kill `pidof /usr/sbin/browserd`");
+		system("kill `pidof browserd`");
 
-	if (!ctx || !ctx->continuous_mode) 
+	if (!ctx || !ctx->continuous_mode)
 		exit(0);
-
-	dbus_request_osso_browser_name(ctx);
 }
 
 static void launch_other_browser(struct swb_context *ctx, char *uri) {
@@ -126,9 +663,11 @@ static void launch_other_browser(struct swb_context *ctx, char *uri) {
 
 	if (!uri || !strcmp(uri, "new_window"))
 		uri = "";
-	urilen = strlen(uri);
-	if (urilen > 0) {
-		/* Quote the URI */
+
+	log_msg("launch_other_browser with uri '%s'\n", uri);
+
+	if ((urilen = strlen(uri)) > 0) {
+		/* Quote the URI to prevent the shell from interpreting it */
 		/* urilen+3 = length of URI + 2x \' + \0 */
 		if (!(quoted_uri = calloc(urilen+3, sizeof(char))))
 			exit(1);
@@ -158,7 +697,7 @@ static void launch_other_browser(struct swb_context *ctx, char *uri) {
 
 			/* Move the string after the ', including the \0,
 			   over two chars */
-			memmove(quote+3, quote+1, strlen(quote)+1);
+			memmove(quote+3, quote+1, strlen(quote));
 			memcpy(quote, "%27", 3);
 			quote = quote + 3;
 		}
@@ -174,65 +713,100 @@ static void launch_other_browser(struct swb_context *ctx, char *uri) {
 	if (!(command = calloc(cmdlen+urilen+1, sizeof(char))))
 		exit(1);
 	snprintf(command, cmdlen+urilen+1, ctx->other_browser_cmd, quoted_uri);
-	printf("command: '%s'\n", command);
+	log_msg("command: '%s'\n", command);
 
 	if (ctx->continuous_mode) {
 		if (fork() != 0) {
 			/* Parent process or error in fork() */
 			if (urilen > 0)
 				free(quoted_uri);
-			free(command);	
+			free(command);
 			return;
 		}
 		/* Child process */
 		setsid();
+		close_stdio();
 	}
 	execl("/bin/sh", "/bin/sh", "-c", command, (char *)NULL);
 }
 
-static void use_other_browser_cmd(struct swb_context *ctx, char *cmd) {
-	size_t len = strlen(cmd);
 
-	free(ctx->other_browser_cmd);
-	ctx->other_browser_cmd = calloc(len+1, sizeof(char));
-	if (!ctx->other_browser_cmd) {
-		printf("malloc failed!\n");
-		ctx->default_browser_launcher = LAUNCH_DEFAULT_BROWSER;
-	} else {
-		ctx->other_browser_cmd = strncpy(ctx->other_browser_cmd,
-						 cmd, len+1);
-		ctx->default_browser_launcher = launch_other_browser;
+/* The list of known browsers and how to launch them */
+static struct browser_launcher browser_launchers[] = {
+	{ "microb", launch_microb, NULL, NULL }, /* First entry is the default! */
+	{ "tear", launch_tear, NULL, "/usr/bin/tear" },
+	{ "fennec", NULL, "fennec %s", "/usr/bin/fennec" },
+	{ "opera", NULL, "opera %s", "/usr/bin/opera" },
+	{ "midori", NULL, "midori %s", "/usr/bin/midori" },
+	{ NULL, NULL, NULL, NULL },
+};
+
+static void use_launcher_as_default(struct swb_context *ctx,
+				    struct browser_launcher *browser) {
+	if (!ctx || !browser)
+		return;
+
+	if (browser->launcher)
+		ctx->default_browser_launcher = browser->launcher;
+	else if (browser->other_browser_cmd) {
+		free(ctx->other_browser_cmd);
+
+		/* Make a copy of the string constant so that
+		   ctx->other_browser_cmd is safe to free() */
+		ctx->other_browser_cmd = strdup(browser->other_browser_cmd);
+		if (!ctx->other_browser_cmd) {
+			log_msg("malloc failed!\n");
+			/* Ideally, we'd configure the built-in default here --
+			   but it's possible we could be called in that path */
+			exit(1);
+		} else
+			ctx->default_browser_launcher = launch_other_browser;
 	}
+
+	return;
 }
 
 void update_default_browser(struct swb_context *ctx, char *default_browser) {
+	struct browser_launcher *browser;
+
 	if (!ctx)
 		return;
 
-	if (!default_browser) {
-		ctx->default_browser_launcher = LAUNCH_DEFAULT_BROWSER;
+	/* Configure the built-in default to start -- that way, we can
+	   handle errors by just returning */
+	use_launcher_as_default(ctx, &browser_launchers[0]);
+
+	if (!default_browser)
+		/* No default_browser configured -- use built-in default */
 		return;
-	}
 
-	if (!strcmp(default_browser, "tear"))
-		ctx->default_browser_launcher = launch_tear;
-	else if (!strcmp(default_browser, "microb"))
-		ctx->default_browser_launcher = launch_microb;
-	else if (!strcmp(default_browser, "fennec"))
-		use_other_browser_cmd(ctx, "fennec %s");
-	else if (!strcmp(default_browser, "midori"))
-		use_other_browser_cmd(ctx, "midori %s");
-	else if (!strcmp(default_browser, "other")) {
+	/* Go through the list of known browser launchers and use one if
+	   it matches */
+	for (browser = browser_launchers; browser->name; ++browser)
+		if (!strcmp(default_browser, browser->name)) {
+			/* Make sure the user's choice is installed on the
+			   system */
+			if (browser->binary && access(browser->binary, X_OK)) {
+				log_msg("%s appears not to be installed\n",
+					default_browser);
+			} else {
+				use_launcher_as_default(ctx, browser);
+				return;
+			}
+		}
+
+	/* Deal with default_browser = "other" */
+	if (!strcmp(default_browser, "other")) {
 		if (ctx->other_browser_cmd)
 			ctx->default_browser_launcher = launch_other_browser;
-		else {
-			printf("default_browser is 'other', but no other_browser_cmd set -- using default\n");
-			ctx->default_browser_launcher = LAUNCH_DEFAULT_BROWSER;
-		}
-	} else {
-		printf("Unknown default_browser %s, using default", default_browser);
-		ctx->default_browser_launcher = LAUNCH_DEFAULT_BROWSER;
+		else
+			log_msg("default_browser is 'other', but no other_browser_cmd set -- using default\n");
+		return;
 	}
+
+	/* Unknown value of default_browser */
+	log_msg("Unknown default_browser %s, using default\n", default_browser);
+	return;
 }
 
 void launch_browser(struct swb_context *ctx, char *uri) {