1 <?xml version="1.0" encoding="ISO-8859-1"?> 2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" 3 "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd"> 4 <!-- lifted from troff+man by doclifter --> 5 <refentry id='dbuslaunch1'> 6 <!-- --> 7 <!-- dbus\-launch manual page. --> 8 <!-- Copyright (C) 2003 Red Hat, Inc. --> 9 10 <refmeta> 11 <refentrytitle>dbus-launch</refentrytitle> 12 <manvolnum>1</manvolnum> 13 </refmeta> 14 <refnamediv id='name'> 15 <refname>dbus-launch</refname> 16 <refpurpose>Utility to start a message bus from a shell script</refpurpose> 17 </refnamediv> 18 <!-- body begins here --> 19 <refsynopsisdiv id='synopsis'> 20 <cmdsynopsis> 21 <command>dbus-launch</command> <arg choice='opt'>--version </arg> 22 <arg choice='opt'>--sh-syntax </arg> 23 <arg choice='opt'>--csh-syntax </arg> 24 <arg choice='opt'>--auto-syntax </arg> 25 <arg choice='opt'>--exit-with-session </arg> 26 <arg choice='opt'>--autolaunch=<replaceable>MACHINEID</replaceable></arg> 27 <arg choice='opt'>--config-file=<replaceable>FILENAME</replaceable></arg> 28 <arg choice='opt'><replaceable>PROGRAM</replaceable></arg> 29 <arg choice='opt' rep='repeat'><replaceable>ARGS</replaceable></arg> 30 <sbr/> 31 </cmdsynopsis> 32 </refsynopsisdiv> 33 34 35 <refsect1 id='description'><title>DESCRIPTION</title> 36 <para>The <command>dbus-launch</command> command is used to start a session bus 37 instance of <emphasis remap='I'>dbus-daemon</emphasis> from a shell script. 38 It would normally be called from a user's login 39 scripts. Unlike the daemon itself, <command>dbus-launch</command> exits, so 40 backticks or the $() construct can be used to read information from 41 <command>dbus-launch</command>.</para> 42 43 <para>With no arguments, <command>dbus-launch</command> will launch a session bus 44 instance and print the address and pid of that instance to standard 45 output.</para> 46 47 <para>You may specify a program to be run; in this case, <command>dbus-launch</command> 48 will launch a session bus instance, set the appropriate environment 49 variables so the specified program can find the bus, and then execute the 50 specified program, with the specified arguments. See below for 51 examples.</para> 52 53 <para>If you launch a program, <command>dbus-launch</command> will not print the 54 information about the new bus to standard output.</para> 55 56 <para>When <command>dbus-launch</command> prints bus information to standard output, by 57 default it is in a simple key-value pairs format. However, you may 58 request several alternate syntaxes using the --sh-syntax, --csh-syntax, 59 --binary-syntax, or 60 --auto-syntax options. Several of these cause <command>dbus-launch</command> to emit shell code 61 to set up the environment.</para> 62 63 <para>With the --auto-syntax option, <command>dbus-launch</command> looks at the value 64 of the SHELL environment variable to determine which shell syntax 65 should be used. If SHELL ends in "csh", then csh-compatible code is 66 emitted; otherwise Bourne shell code is emitted. Instead of passing 67 --auto-syntax, you may explicity specify a particular one by using 68 --sh-syntax for Bourne syntax, or --csh-syntax for csh syntax. 69 In scripts, it's more robust to avoid --auto-syntax and you hopefully 70 know which shell your script is written in.</para> 71 72 73 <para>See <ulink url='http://www.freedesktop.org/software/dbus/'>http://www.freedesktop.org/software/dbus/</ulink> for more information 74 about D-Bus. See also the man page for <emphasis remap='I'>dbus-daemon</emphasis>.</para> 75 76 77 <para>Here is an example of how to use <command>dbus-launch</command> with an 78 sh-compatible shell to start the per-session bus daemon:</para> 79 <literallayout remap='.nf'> 80 81 ## test for an existing bus daemon, just to be safe 82 if test -z "$DBUS_SESSION_BUS_ADDRESS" ; then 83 ## if not found, launch a new one 84 eval `dbus-launch --sh-syntax --exit-with-session` 85 echo "D-Bus per-session daemon address is: $DBUS_SESSION_BUS_ADDRESS" 86 fi 87 88 </literallayout> <!-- .fi --> 89 <para>You might run something like that in your login scripts.</para> 90 91 92 <para>Another way to use <command>dbus-launch</command> is to run your main session 93 program, like so:</para> 94 <literallayout remap='.nf'> 95 96 dbus-launch gnome-session 97 98 </literallayout> <!-- .fi --> 99 <para>The above would likely be appropriate for ~/.xsession or ~/.Xclients.</para> 100 101 </refsect1> 102 103 <refsect1 id='automatic_launching'><title>AUTOMATIC LAUNCHING</title> 104 <para>If DBUS_SESSION_BUS_ADDRESS is not set for a process that tries to use 105 D-Bus, by default the process will attempt to invoke dbus-launch with 106 the --autolaunch option to start up a new session bus or find the 107 existing bus address on the X display or in a file in 108 ~/.dbus/session-bus/</para> 109 110 111 <para>Whenever an autolaunch occurs, the application that had to 112 start a new bus will be in its own little world; it can effectively 113 end up starting a whole new session if it tries to use a lot of 114 bus services. This can be suboptimal or even totally broken, depending 115 on the app and what it tries to do.</para> 116 117 118 <para>There are two common reasons for autolaunch. One is ssh to a remote 119 machine. The ideal fix for that would be forwarding of 120 DBUS_SESSION_BUS_ADDRESS in the same way that DISPLAY is forwarded. 121 In the meantime, you can edit the session.conf config file to 122 have your session bus listen on TCP, and manually set 123 DBUS_SESSION_BUS_ADDRESS, if you like.</para> 124 125 126 <para>The second common reason for autolaunch is an su to another user, and 127 display of X applications running as the second user on the display 128 belonging to the first user. Perhaps the ideal fix in this case 129 would be to allow the second user to connect to the session bus of the 130 first user, just as they can connect to the first user's display. 131 However, a mechanism for that has not been coded.</para> 132 133 134 <para>You can always avoid autolaunch by manually setting 135 DBUS_SESSION_BUS_ADDRESS. Autolaunch happens because the default 136 address if none is set is "autolaunch:", so if any other address is 137 set there will be no autolaunch. You can however include autolaunch in 138 an explicit session bus address as a fallback, for example 139 DBUS_SESSION_BUS_ADDRESS="something:,autolaunch:" - in that case if 140 the first address doesn't work, processes will autolaunch. (The bus 141 address variable contains a comma-separated list of addresses to try.)</para> 142 143 144 <para>The --autolaunch option is considered an internal implementation 145 detail of libdbus, and in fact there are plans to change it. There's 146 no real reason to use it outside of the libdbus implementation anyhow.</para> 147 148 </refsect1> 149 150 <refsect1 id='options'><title>OPTIONS</title> 151 <para>The following options are supported:</para> 152 <variablelist remap='TP'> 153 <varlistentry> 154 <term><option>--auto-syntax</option></term> 155 <listitem> 156 <para>Choose --csh-syntax or --sh-syntax based on the SHELL environment variable.</para> 157 158 <para><option>--binary-syntax</option> 159 Write to stdout a nul-terminated bus address, then the bus PID as a 160 binary integer of size sizeof(pid_t), then the bus X window ID as a 161 binary integer of size sizeof(long). Integers are in the machine's 162 byte order, not network byte order or any other canonical byte order.</para> 163 164 </listitem> 165 </varlistentry> 166 <varlistentry> 167 <term><option>--close-stderr</option></term> 168 <listitem> 169 <para>Close the standard error output stream before starting the D-Bus 170 daemon. This is useful if you want to capture dbus-launch error 171 messages but you don't want dbus-daemon to keep the stream open to 172 your application.</para> 173 174 </listitem> 175 </varlistentry> 176 <varlistentry> 177 <term><option>--config-file=FILENAME</option></term> 178 <listitem> 179 <para>Pass --config-file=FILENAME to the bus daemon, instead of passing it 180 the --session argument. See the man page for dbus-daemon</para> 181 182 </listitem> 183 </varlistentry> 184 <varlistentry> 185 <term><option>--csh-syntax</option></term> 186 <listitem> 187 <para>Emit csh compatible code to set up environment variables.</para> 188 189 </listitem> 190 </varlistentry> 191 <varlistentry> 192 <term><option>--exit-with-session</option></term> 193 <listitem> 194 <para>If this option is provided, a persistent "babysitter" process will be 195 created that watches stdin for HUP and tries to connect to the X 196 server. If this process gets a HUP on stdin or loses its X connection, 197 it kills the message bus daemon.</para> 198 199 </listitem> 200 </varlistentry> 201 <varlistentry> 202 <term><option>--autolaunch=MACHINEID</option></term> 203 <listitem> 204 <para>This option implies that <command>dbus-launch</command> should scan for a 205 previously-started session and reuse the values found there. If no 206 session is found, it will start a new session. The 207 --exit-with-session option is implied if --autolaunch is given. 208 This option is for the exclusive use of libdbus, you do not want to 209 use it manually. It may change in the future.</para> 210 211 </listitem> 212 </varlistentry> 213 <varlistentry> 214 <term><option>--sh-syntax</option></term> 215 <listitem> 216 <para>Emit Bourne-shell compatible code to set up environment variables.</para> 217 218 </listitem> 219 </varlistentry> 220 <varlistentry> 221 <term><option>--version</option></term> 222 <listitem> 223 <para>Print the version of dbus-launch</para> 224 225 </listitem> 226 </varlistentry> 227 </variablelist> 228 </refsect1> 229 230 <refsect1 id='author'><title>AUTHOR</title> 231 <para>See <ulink url='http://www.freedesktop.org/software/dbus/doc/AUTHORS'>http://www.freedesktop.org/software/dbus/doc/AUTHORS</ulink></para> 232 233 </refsect1> 234 235 <refsect1 id='bugs'><title>BUGS</title> 236 <para>Please send bug reports to the D-Bus mailing list or bug tracker, 237 see <ulink url='http://www.freedesktop.org/software/dbus/'>http://www.freedesktop.org/software/dbus/</ulink></para> 238 </refsect1> 239 </refentry> 240 241
