From b81e43465b14836b17e4fe2dea91c78a2bdd29b3 Mon Sep 17 00:00:00 2001 From: Timothy Pearson Date: Sun, 22 Jan 2012 01:02:36 -0600 Subject: Part 2 of prior commit --- tdm/backend/daemon.c | 78 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 78 insertions(+) create mode 100644 tdm/backend/daemon.c (limited to 'tdm/backend/daemon.c') diff --git a/tdm/backend/daemon.c b/tdm/backend/daemon.c new file mode 100644 index 000000000..79d9e47ff --- /dev/null +++ b/tdm/backend/daemon.c @@ -0,0 +1,78 @@ +/* + +Copyright 1988, 1998 The Open Group +Copyright 2000,2001,2003 Oswald Buddenhagen + +Permission to use, copy, modify, distribute, and sell this software and its +documentation for any purpose is hereby granted without fee, provided that +the above copyright notice appear in all copies and that both that +copyright notice and this permission notice appear in supporting +documentation. + +The above copyright notice and this permission notice shall be included +in all copies or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS +OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF +MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. +IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR +OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, +ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR +OTHER DEALINGS IN THE SOFTWARE. + +Except as contained in this notice, the name of a copyright holder shall +not be used in advertising or otherwise to promote the sale, use or +other dealings in this Software without prior written authorization +from the copyright holder. + +*/ + +/* + * xdm - display manager daemon + * Author: Keith Packard, MIT X Consortium + */ + +#include "dm.h" +#include "dm_error.h" + +void +BecomeDaemon( void ) +{ + int pfd[2]; + + /* + * fork so that the process goes into the background automatically. Also + * has a nice side effect of having the child process get inherited by + * init (pid 1). + * Create a pipe and block on it, so the parent knows when the child is + * done with detaching. This eliminates the possibility that the child + * might get killed when the init script that's running xdm exits. + */ + + if (pipe( pfd )) + pfd[0] = pfd[1] = -1; /* so what ...? */ + switch (fork ()) { + case 0: + /* child */ + break; + case -1: + /* error */ + LogError( "Daemon fork failed: %m\n" ); + break; + + default: + /* parent */ + close( pfd[1] ); + read( pfd[0], &pfd[1] /* dummy */, 1 ); + exit( 0 ); + } + + /* don't use daemon() - it doesn't buy us anything but an additional fork */ + + setsid(); + + close( pfd[0] ); + close( pfd[1] ); /* tell parent that we're done with detaching */ + + chdir( "/" ); +} -- cgit v1.2.1