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libtdevnc/x11vnc/misc/Xdummy

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31 KiB

#!/bin/sh
#
# Xdummy: an LD_PRELOAD hack to run a stock XFree86(1) or Xorg(1) server
# with the "dummy" video driver to make it avoid Linux VT switching, etc.
#
# Run "Xdummy -help" for more info.
#
xserver=""
geom=""
install=""
uninstall=""
root=1
debug=""
strace=""
runit=1
prconf=""
noconf=""
PATH=$PATH:/bin:/usr/bin
export PATH
program=`basename "$0"`
help () {
${PAGER:-more} << END
$program: a hack to run a stock XFree86(1) or Xorg(1) server with the
"dummy" video driver such that it AVOIDS the Linux VT switching, keyboard
mouse conflicts, etc associated with normal use of "dummy".
In other words, try to make XFree86/Xorg with the Device "dummy" driver
act more like Xvfb(1).
To achieve this, while running the real Xserver $program intercepts system
and library calls via the LD_PRELOAD method and modifies the behavior
to make it work correctly (i.e. avoid the VT stuff). LD_PRELOAD tricks
are usually "clever hacks" and so might not work in all circumstances.
The primary motivation for the Xdummy script is to provide a virtual X
server for x11vnc but with more features than Xvfb (or Xvnc), however
it could be used for other reasons (e.g. better automated testing than
with Xvfb).
Currently this program needs to be run as root, since it is too difficult
to trick it otherwise. Hopefully this will be relaxed at a later date
if the needed tricks are discovered.
Also, gcc/cc is required to compile the LD_PRELOAD shared object.
See -install and -uninstall described below.
Usage:
$program <${program}-args> [--] <Xserver-args>
Examples:
$program :1
$program -debug -tmpdir ~/mytmp :1
$program -install
startx example:
startx -e bash -- $program :2 -depth 16
(startx needs to be run as root, you can su(1) to a normal user
in the bash shell and then launch ~/.xinitrc or ~/.xsession,
gnome-session, startkde, startxfce4, etc.)
xdm example:
xdm -config /usr/local/dummy/xdm-config -nodaemon
where the xdm-config file has line:
DisplayManager.servers: /usr/local/dummy/Xservers
and /usr/local/dummy/Xservers has lines:
:1 local /usr/local/dummy/Xdummy :1 -debug
:2 local /usr/local/dummy/Xdummy :2 -debug
gdm/kdm example:
TBD.
Root permission and x11vnc:
This program needs to be run as root. One could run x11vnc as
root with -unixpw (it switches to the user that logs in) and
that may be OK, some other ideas:
- add this to sudo via visudo:
ALL ALL = NOPASSWD: /usr/local/bin/Xdummy
- use this little suid wrapper:
/*
* xdummy.c
*
cc -o ./xdummy xdummy.c
sudo cp ./xdummy /usr/local/bin/xdummy
sudo chown root:root /usr/local/bin/xdummy
sudo chmod u+s /usr/local/bin/xdummy
*
*/
#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>
#include <stdio.h>
int main (int argc, char *argv[]) {
extern char **environ;
char str[100];
sprintf(str, "XDUMMY_UID=%d", (int) getuid());
putenv(str);
setuid(0);
setgid(0);
execv("/usr/local/bin/Xdummy", argv);
exit(1);
return 1;
}
Options:
${program}-args:
-install Compile the LD_PRELOAD shared object and install it
next to the $program script file as: $0.so
When that file exists it is used as the LD_PRELOAD
shared object without recompiling. Otherwise,
each time $program is run the LD_PRELOAD shared
object is compiled as a file in /tmp (or -tmpdir).
-uninstall Remove the file: $0.so
The LD_PRELOAD shared object will then be compiled
each time this program is run.
Note: the X server is not started under -install or -uninstall.
:N The DISPLAY can be the first $program argument.
It is passed to the real X server. This is to
aid use with startx(1), xinit(1), xdm(1), etc.
-geom geom1[,geom2...] Take the geometry (e.g. 1024x768) or
list of geometries and insert them into the
Screen section of the tweaked X server
config file. Use this to have a smaller geometry
than the one in the system config file.
-tmpdir dir Specify a temporary directory, owned by you and
only writable by you. This is used in place of
/tmp/Xdummy.\$USER/ to placed the $program.so
shared object, tweaked config files, etc.
-nonroot Try to run in non-root mode (XXX NOT yet working).
-nosudo Do not try to use sudo(1) when re-running as root,
use su(1) instead.
-xserver path Specify the path to the Xserver to use. Default
is to try "Xorg" first and then "XFree86". If
those are not in \$PATH, use these locations:
/usr/X11R6/bin/Xorg
/usr/X11R6/bin/XFree86
-n Do not run the command to start the X server,
just show the command that $program would run.
The LD_PRELOAD shared object will be built,
if needed.
-prconf Print, to stdout, the tweaked Xorg or XFree86
config file (-config and -xf86config server
options, respectively). The Xserver is not
started.
-noconf Do not tweak the Xorg or XFree86 config file
(system or server command line) at all. It is
up to you to make sure it is a working config
file (e.g. "dummy" driver, etc). Perhaps you
want to use a file based on -prconf output.
-debug Extra debugging output.
-strace strace(1) the Xserver process (for debugging).
-h, -help Print out this help.
Xserver-args:
Most of the XFree86 and Xorg options will work. Important ones
that may be supplied if missing:
:N X Display number for server to use.
vtNN Linux virtual terminal (VT) to use (a VT is currently
still used, just not switched to and from).
-config file Driver "dummy" tweaked config file, a
-xf86config file number of settings are tweaked besides Driver.
If -config/-xf86config is not given, the system one is used.
Any settings in the config file that are not consistent with
"dummy" mode will be overwritten (unless -noconf is used).
Notes:
The XFree86/Xorg "dummy" driver is currently undocmented. It works
well in this mode, but it is evidently not intended for end users.
If the display Xserver-arg (e.g. :1) is not given, or ":" or ":9999"
is given that indicates $program should try to find a free one.
If the display virtual terminal, VT, (e.g. vt9) is not given that
indicates $program should try to find a free one (or guess a high one).
This program is not completely secure WRT files in /tmp (but it
tries to some degree). Better is to use the -tmpdir option to supply a
directory only writable by you. Even better is to get rid of users on
the local machine you do not trust :-)
END
}
warn() {
echo "$*" 1>&2
}
#set -xv
if [ "X$XDUMMY_UID" = "X" ]; then
XDUMMY_UID=`id -u`
export XDUMMY_UID
fi
if [ "X$XDUMMY_UID" = "X0" ]; then
if [ "X$SUDO_UID" != "X" ]; then
XDUMMY_UID=$SUDO_UID
export XDUMMY_UID
fi
fi
#warn "id: `id -u`"
# See if it needs to be run as root:
if [ "X$XDUMMY_SU_EXEC" = "X" -a "X`id -u`" != "X0" ]; then
dosu=1
nosudo=""
XDUMMY_SU_EXEC=1
export XDUMMY_SU_EXEC
for arg in $*
do
#echo "arg=$arg"
if [ "X$arg" = "X-nonroot" ]; then
dosu=""
elif [ "X$arg" = "X-noroot" ]; then
dosu=""
elif [ "X$arg" = "X-nosudo" ]; then
nosudo="1"
elif [ "X$arg" = "X-help" ]; then
dosu=""
elif [ "X$arg" = "X-h" ]; then
dosu=""
elif [ "X$arg" = "X-install" ]; then
dosu=""
elif [ "X$arg" = "X-uninstall" ]; then
dosu=""
elif [ "X$arg" = "X-n" ]; then
dosu=""
elif [ "X$arg" = "X-prconf" ]; then
dosu=""
elif [ "X$arg" = "X--" ]; then
break
fi
done
if [ $dosu ]; then
warn "$program: currently needs to be run as root to work."
if type sudo > /dev/null 2>&1; then
:
else
nosudo=1
fi
if [ "X$nosudo" = "X" ]; then
warn "$program: supply the sudo password to restart as root:"
if [ "X$XDUMMY_UID" != "X" ]; then
exec sudo $0 -uid $XDUMMY_UID "$@"
else
exec sudo $0 "$@"
fi
else
warn "$program: supply the root password to restart as root:"
if [ "X$XDUMMY_UID" != "X" ]; then
exec su -c "$0 -uid $XDUMMY_UID $*"
else
exec su -c "$0 $*"
fi
fi
exit
fi
fi
#warn "args: $*"
disp=""
# Process Xdummy args:
while [ "X$1" != "X" ]
do
case $1 in
":"*) disp=$1
;;
"-install") install=1
;;
"-uninstall") uninstall=1
;;
"-nonroot") root=""
;;
"-noroot") root=""
;;
"-nosudo") nosudo=1
;;
"-xserver") xserver="$2"; shift
;;
"-uid") XDUMMY_UID="$2"; shift
export XDUMMY_UID
;;
"-geom"*) geom="$2"; shift
;;
"-tmpdir") XDUMMY_TMPDIR="$2"; shift
;;
"-n") runit=""
;;
"-no") runit=""
;;
"-prconf") prconf=1
;;
"-noconf") noconf=1
;;
"-debug") debug=1
;;
"-nodebug") debug=""
;;
"-strace") strace=1
;;
"-h"*) help; exit 0
;;
"--") shift; break
;;
*) break
;;
esac
shift
done
# Try to get a username for use in our tmp directory, etc.
user=""
if [ X`id -u` = "X0" ]; then
user=root # this will also be used below for id=0
elif [ "X$USER" != "X" ]; then
user=$USER
elif [ "X$LOGNAME" != "X" ]; then
user=$LOGNAME
fi
# keep trying...
if [ "X$user" = "X" ]; then
user=`whoami 2>/dev/null`
fi
if [ "X$user" = "X" ]; then
user=`basename "$HOME"`
fi
if [ "X$user" = "X" -o "X$user" = "X." ]; then
user="u$$"
fi
if [ "X$debug" = "X1" ]; then
echo ""
echo "/usr/bin/env:"
env
echo ""
fi
# Function to compile the LD_PRELOAD shared object:
make_so() {
# extract code embedded in this script into a tmp C file:
n1=`grep -n '^#code_begin' $0 | head -1 | awk -F: '{print $1}'`
n2=`grep -n '^#code_end' $0 | head -1 | awk -F: '{print $1}'`
n1=`expr $n1 + 1`
dn=`expr $n2 - $n1`
tmp=$tdir/Xdummy.$$.c
rm -f $tmp
if [ -e $tmp -o -h $tmp ]; then
warn "$tmp still exists."
exit 1
fi
tail +$n1 $0 | head -$dn > $tmp
# compile it to Xdummy.so:
rm -f $SO
touch $SO
if [ ! -f $SO ]; then
SO=$tdir/Xdummy.$user.so
warn "warning switch LD_PRELOAD shared object to: $SO"
fi
rm -f $SO
# we assume gcc:
cc -shared -fPIC -o $SO $tmp
rc=$?
rm -f $tmp
if [ $rc != 0 ]; then
warn "$program: cannot build $SO"
exit 1
fi
if [ "X$debug" != "X" -o "X$install" != "X" ]; then
warn "$program: created $SO"
ls -l "$SO"
fi
}
# Set tdir to tmp dir for make_so():
if [ "X$XDUMMY_TMPDIR" != "X" ]; then
tdir=$XDUMMY_TMPDIR
mkdir -p $tdir
else
tdir="/tmp"
fi
# Handle -install/-uninstall case:
SO=$0.so
if [ "X$install" != "X" -o "X$uninstall" != "X" ]; then
if [ -e $SO -o -h $SO ]; then
warn "removing $SO"
fi
rm -f $SO
if [ -e $SO -o -h $SO ]; then
# not good...
warn "warning: $SO still exists."
exit 1
fi
if [ $install ]; then
make_so
if [ ! -f $SO ]; then
exit 1
fi
fi
exit 0
fi
# We need a tmp directory for the .so, tweaked config file, and for
# redirecting filenames we cannot create (under -nonroot, not yet
# working).
#
if [ "X$XDUMMY_TMPDIR" = "X" ]; then
XDUMMY_TMPDIR="/tmp/Xdummy.$user"
fi
tmp=$XDUMMY_TMPDIR
if echo "$tmp" | grep '^/tmp' > /dev/null; then
if [ "X$tmp" != "X/tmp" -a "X$tmp" != "X/tmp/" ]; then
# clean this subdir of /tmp out, otherwise leave it...
rm -rf $XDUMMY_TMPDIR
if [ -e $XDUMMY_TMPDIR ]; then
warn "$XDUMMY_TMPDIR still exists"
exit 1
fi
fi
fi
mkdir -p $XDUMMY_TMPDIR
chmod 700 $XDUMMY_TMPDIR
# see if we can write something there:
tfile="$XDUMMY_TMPDIR/test.file"
touch $tfile
if [ ! -f $tfile ]; then
XDUMMY_TMPDIR="/tmp/Xdummy.$$.$USER"
warn "warning: setting tmpdir to $XDUMMY_TMPDIR ..."
rm -rf $XDUMMY_TMPDIR || exit 1
mkdir -p $XDUMMY_TMPDIR || exit 1
fi
rm -f $tfile
export XDUMMY_TMPDIR
# compile the LD_PRELOAD shared object if needed:
if [ ! -f $SO ]; then
SO="$XDUMMY_TMPDIR/Xdummy.so"
make_so
fi
# decide which X server to use:
if [ "X$xserver" = "X" ]; then
if type Xorg >/dev/null 2>&1; then
xserver="Xorg"
elif type XFree86 >/dev/null 2>&1; then
xserver="XFree86"
elif -x /usr/X11R6/bin/Xorg; then
xserver="/usr/X11R6/bin/Xorg"
elif -x /usr/bin/Xorg; then
xserver="/usr/bin/Xorg"
elif -x /usr/X11R6/bin/XFree86; then
xserver="/usr/X11R6/bin/XFree86"
fi
if [ "X$xserver" = "X" ]; then
# just let it fail below.
xserver="/usr/X11R6/bin/Xorg"
warn "$program: cannot locate a stock Xserver... assuming $xserver"
fi
fi
# see if the binary is suid or not readable under -nonroot (XXX not yet useful):
xserver_path=`type -p $xserver 2>/dev/null`
if [ -e "$xserver_path" -a "X$root" = "X" -a "X$runit" != "X" ]; then
if [ ! -r $xserver_path -o -u $xserver_path ]; then
# XXX not quite correct with rm -rf $XDUMMY_TMPDIR ...
base=`basename "$xserver_path"`
#new="$tdir/$base.$user"
new="/tmp/$base.$user"
if [ ! -e $new ]; then
warn "NEED TO COPY UNREADABLE $xserver_path to $new as root:"
warn ""
ls -l $xserver_path 1>&2
warn ""
warn "This only needs to be done once."
warn "Please supply root passwd to 'su -c'"
touch $new || exit 1
chmod 700 $new || exit 1
su -c "cat $xserver_path > $new"
ls -l $new
warn "Please restart."
exit 0
elif [ ! -O $new ]; then
warn "file \"$new\" not owned by us!"
ls -l $new
exit 1
fi
xserver=$new
fi
fi
# work out display:
if [ "X$disp" != "X" ]; then
:
elif [ "X$1" != "X" ]; then
if echo "$1" | grep '^:[0-9]' > /dev/null; then
disp=$1
shift
elif [ "X$1" = "X:" ]; then
# ":" means for us to find one.
shift
fi
fi
if [ "X$disp" = "X" -o "X$disp" = "X:" ]; then
# try to find an open display port:
ports=`netstat -ant | grep LISTEN | awk '{print $4}' | sed -e 's/^.*://'`
n=0
while [ $n -le 20 ]
do
port=`printf "60%02d" $n`
if echo "$ports" | grep "^${port}\$" > /dev/null; then
:
else
disp=":$n"
warn "$program: auto-selected DISPLAY $disp"
break
fi
n=`expr $n + 1`
done
fi
# work out which vt to use, try to find an open one if necessary.
vt=""
for arg in $*
do
if echo "$arg" | grep '^vt' > /dev/null; then
vt=$arg
break
fi
done
if [ "X$vt" = "X" ]; then
if [ "X$user" = "Xroot" ]; then
# root can user fuser(1) to see if it is in use:
if type fuser >/dev/null 2>&1; then
# try /dev/tty17 thru /dev/tty32
n=17
while [ $n -le 32 ]
do
dev="/dev/tty$n"
if fuser $dev >/dev/null 2>&1; then
:
else
vt="vt$n"
warn "$program: auto-selected VT $vt => $dev"
break
fi
n=`expr $n + 1`
done
fi
fi
if [ "X$vt" = "X" ]; then
# take a wild guess...
vt=vt16
warn "$program: selected VT $vt"
fi
else
vt=""
fi
# decide flavor of Xserver:
stype=`basename "$xserver"`
if echo "$stype" | grep -i xorg > /dev/null; then
stype=xorg
else
stype=xfree86
fi
# work out config file and tweak it.
next=""
config=""
got_config=""
for arg in $*
do
if [ $next ]; then
config="$arg"
got_config=1
break
fi
if [ "X$arg" = "X-xf86config" ]; then
stype="xfree86"
next=1
elif [ "X$arg" = "X-config" ]; then
stype="xorg"
next=1
fi
done
tweak_config() {
in="$1"
config2="$XDUMMY_TMPDIR/xconfig"
if [ "X$disp" != "X" ]; then
d=`echo "$disp" | sed -e 's,/,,g' -e 's/:/_:/g'`
config2="$config2$d"
fi
# perl script to tweak the config file... add/delete options, etc.
XDUMMY_GEOM=$geom; export XDUMMY_GEOM
perl > $config2 < $in -e '
$n = 0;
$geom = $ENV{XDUMMY_GEOM};
if ($geom ne "") {
$tmp = "";
foreach $g (split(/,/, $geom)) {
$tmp .= "\"$g\" ";
}
$tmp =~ s/\s*$//;
$geom = $tmp;
}
while (<>) {
$n++;
if (/^\s*#/) {
# pass comments straight thru
print;
next;
}
if (/^\s*Section\s+(\S+)/i) {
# start of Section
$sect = $1;
$sect =~ s/\W//g;
$sect =~ y/A-Z/a-z/;
$sects{$sect} = 1;
print;
next;
}
if (/^\s*EndSection/) {
# end of Section
if ($sect eq "serverflags") {
if (!$got_DontVTSwitch) {
print " ##Xdummy:##\n";
print " Option \"DontVTSwitch\" \"true\"\n";
}
if (!$got_AllowMouseOpenFail) {
print " ##Xdummy:##\n";
print " Option \"AllowMouseOpenFail\" \"true\"\n";
}
if (!$got_PciForceNone) {
print " ##Xdummy:##\n";
print " Option \"PciForceNone\" \"true\"\n";
}
} elsif ($sect eq "device") {
if (!$got_Driver) {
print " ##Xdummy:##\n";
print " Driver \"dummy\"\n";
}
if (!$got_VideoRam) {
print " ##Xdummy:##\n";
print " VideoRam 16000\n";
}
}
$sect = "";
print;
next;
}
$l = $_;
$l =~ s/#.*$//;
if ($sect eq "serverflags") {
if ($l =~ /^\s*Option.*DontVTSwitch/i) {
$_ =~ s/false/true/ig;
$got_DontVTSwitch = 1;
}
if ($l =~ /^\s*Option.*AllowMouseOpenFail/i) {
$_ =~ s/false/true/ig;
$got_AllowMouseOpenFail = 1;
}
if ($l =~ /^\s*Option.*PciForceNone/i) {
$_ =~ s/false/true/ig;
$got_PciForceNone= 1;
}
}
if ($sect eq "module") {
if ($l =~ /^\s*Load.*\b(dri|fbdevhw)\b/i) {
$_ = "##Xdummy## $_";
}
}
if ($sect eq "device") {
if ($l =~ /^(\s*Driver)\b/i) {
$_ = "$1 \"dummy\"\n";
$got_Driver = 1;
}
if ($l =~ /^\s*VideoRam/i) {
$got_VideoRam= 1;
}
}
if ($sect eq "inputdevice") {
if ($l =~ /^\s*Option.*\bDevice\b/i) {
print " ##Xdummy:##\n";
$_ = " Option \"Device\" \"/dev/dilbert$n\"\n";
}
}
if ($sect eq "screen") {
if ($geom ne "") {
if ($l =~ /^(\s*Modes)\b/i) {
$_ = "$1 $geom\n";
print " ##Xdummy:##\n";
$got_Modes = 1;
}
}
}
print;
}
# create any crucial sections that are missing:
if (! exists($sects{serverflags})) {
print "\n##Xdummy:##\n";
print "Section \"ServerFlags\"\n";
print " Option \"DontVTSwitch\" \"true\"\n";
print " Option \"AllowMouseOpenFail\" \"true\"\n";
print " Option \"PciForceNone\" \"true\"\n";
print "EndSection\n";
}
if (! exists($sects{device})) {
print "\n##Xdummy:##\n";
print "Section \"Device\"\n";
print " Identifier \"Videocard0\"\n";
print " Driver \"dummy\"\n";
print " VideoRam 16000\n";
print "EndSection\n";
}
if (! exists($sects{monitor})) {
print "\n##Xdummy:##\n";
print "Section \"Monitor\"\n";
print " Identifier \"Monitor0\"\n";
print " HorizSync 30.0 - 130.0\n";
print " VertRefresh 50.0 - 250.0\n";
print "EndSection\n";
}
if (! exists($sects{screen})) {
print "\n##Xdummy:##\n";
print "Section \"Screen\"\n";
print " Identifier \"Screen0\"\n";
print " Device \"Videocard0\"\n";
print " Monitor \"Monitor0\"\n";
print " DefaultDepth 16\n";
print " SubSection \"Display\"\n";
print " Viewport 0 0\n";
print " Depth 16\n";
print " Modes \"1024x768\" \"800x600\" \"640x480\"\n";
print " EndSubSection\n";
print "EndSection\n";
}
';
}
args="$*"
if [ ! $noconf ]; then
# tweaked config will be put in $config2:
config2=""
if [ "X$config" != "X" ]; then
if [ ! -f $config ]; then
config="/etc/X11/$config"
fi
else
# use the default one:
if [ "X$stype" = "Xxorg" ]; then
config=/etc/X11/xorg.conf
else
if [ -f "/etc/X11/XF86Config-4" ]; then
config="/etc/X11/XF86Config-4"
else
config="/etc/X11/XF86Config"
fi
fi
if [ ! -f $config ]; then
for c in /etc/X11/xorg.conf /etc/X11/XF86Config-4 /etc/X11/XF86Config
do
if [ -f $c ]; then
config=$c
break
fi
done
fi
fi
if [ -f $config ]; then
tweak_config $config
fi
# now we need to get our tweaked config file onto the command line:
if [ ! $got_config ]; then
# append:
if [ "X$stype" = "Xxorg" ]; then
args="$args -config FUBAR"
else
args="$args -xf86config FUBAR"
fi
fi
if [ "X$config2" != "X" ]; then
# or modify $args:
args=`echo "$args" | sed \
-e "s,-config *[^ ][^ ]*,-config $config2,g" \
-e "s,-xf86config *[^ ][^ ]*,-xf86config $config2,g"`
fi
fi
if [ $prconf ]; then
warn ""
warn "The Xorg/XFree86 server config file is:"
warn ""
if [ "X$config2" = "X" ]; then
warn "NO CONFIG GENERATED."
else
cat "$config2"
fi
exit
fi
if [ $debug ]; then
XDUMMY_DEBUG=1
export XDUMMY_DEBUG
fi
if [ $root ]; then
XDUMMY_ROOT=1
export XDUMMY_ROOT
fi
# finally, run it:
if [ "X$debug" != "X" -o "X$runit" = "X" ]; then
warn ""
warn "The command to run is:"
warn ""
so=$SO
pwd=`pwd`
if echo "$so" | grep '^\./' > /dev/null; then
so=`echo "$so" | sed -e "s,^\.,$pwd,"`
fi
if echo "$so" | grep '/' > /dev/null; then
:
else
so="$pwd/$so"
fi
warn "env LD_PRELOAD=$so $xserver $disp $args $vt"
warn ""
if [ ! $runit ]; then
exit 0
fi
fi
if [ $strace ]; then
strace -f env LD_PRELOAD=$SO $xserver $disp $args $vt
else
exec env LD_PRELOAD=$SO $xserver $disp $args $vt
fi
exit $?
#########################################################################
code() {
#code_begin
#include <stdio.h>
#define O_ACCMODE 0003
#define O_RDONLY 00
#define O_WRONLY 01
#define O_RDWR 02
#define O_CREAT 0100 /* not fcntl */
#define O_EXCL 0200 /* not fcntl */
#define O_NOCTTY 0400 /* not fcntl */
#define O_TRUNC 01000 /* not fcntl */
#define O_APPEND 02000
#define O_NONBLOCK 04000
#define O_NDELAY O_NONBLOCK
#define O_SYNC 010000
#define O_FSYNC O_SYNC
#define O_ASYNC 020000
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <linux/vt.h>
#include <linux/kd.h>
#define __USE_GNU
#include <dlfcn.h>
static char tmpdir[1024];
static char str1[1024];
static char str2[1024];
static char devs[256][1024];
static int debug = -1;
static int root = -1;
static int changed_uid = 0;
static int saw_fonts = 0;
#if 0
typedef long time_t;
#endif
static time_t start = 0;
void check_debug(void) {
if (debug < 0) {
if (getenv("XDUMMY_DEBUG") != NULL) {
debug = 1;
} else {
debug = 0;
}
putenv("LD_PRELOAD=");
}
}
void check_root(void) {
if (root < 0) {
if (getenv("XDUMMY_ROOT") != NULL) {
root = 1;
} else {
root = 0;
}
}
}
void check_uid(void) {
if (start == 0) {
start = time(NULL);
if (debug) fprintf(stderr, "START: %d\n", start);
return;
} else if (changed_uid == 0) {
if (saw_fonts || time(NULL) > start + 20) {
if (getenv("XDUMMY_UID")) {
int uid = atoi(getenv("XDUMMY_UID"));
if (debug) fprintf(stderr, "SETREUID: %d\n", uid);
if (uid >= 0) {
setreuid(uid, -1);
}
}
changed_uid = 1;
}
}
}
#define CHECKIT if (debug < 0) check_debug(); \
if (root < 0) check_root(); \
check_uid();
static void set_tmpdir(void) {
char *s;
static int didset = 0;
if (didset) {
return;
}
s = getenv("XDUMMY_TMPDIR");
if (! s) {
s = "/tmp";
}
tmpdir[0] = '\0';
strcat(tmpdir, s);
strcat(tmpdir, "/");
didset = 1;
}
static char *tmpdir_path(const char *path) {
char *str;
set_tmpdir();
strcpy(str2, path);
str = str2;
while (*str) {
if (*str == '/') {
*str = '_';
}
str++;
}
strcpy(str1, tmpdir);
strcat(str1, str2);
return str1;
}
int open(const char *pathname, int flags, unsigned short mode) {
int fd;
char *store_dev = NULL;
static int (*real_open)(const char *, int , unsigned short) = NULL;
CHECKIT
if (! real_open) {
real_open = (int (*)(const char *, int , unsigned short))
dlsym(RTLD_NEXT, "open");
}
if (! root) {
if (!strcmp(pathname, "/dev/mem")) {
;
} else if (!strcmp(pathname, "/dev/tty")) {
;
} else if (strstr(pathname, "/dev") == pathname) {
store_dev = strdup(pathname);
pathname = tmpdir_path(pathname);
if (debug) fprintf(stderr, "OPEN: -> %s\n", pathname);
fd = real_open(pathname, O_WRONLY|O_CREAT, 0777);
close(fd);
}
}
fd = real_open(pathname, flags, mode);
if (debug) fprintf(stderr, "OPEN: %s %d %d fd=%d\n",
pathname, flags, mode, fd);
if (! root) {
if (store_dev && fd < 256) {
if (fd < 256) {
strcpy(devs[fd], store_dev);
}
free(store_dev);
}
}
return(fd);
}
int open64(const char *pathname, int flags, unsigned short mode) {
int fd;
CHECKIT
if (debug) fprintf(stderr, "OPEN64: %s %d %d\n", pathname, flags, mode);
fd = open(pathname, flags, mode);
return(fd);
}
FILE *fopen(const char *pathname, const char *mode) {
static FILE* (*real_fopen)(const char *, const char *) = NULL;
char *str;
if (! saw_fonts) {
if (strstr(pathname, "/fonts/")) {
if (strstr(pathname, "fonts.dir")) {
saw_fonts = 1;
} else if (strstr(pathname, "fonts.alias")) {
saw_fonts = 1;
}
}
}
CHECKIT
if (! real_fopen) {
real_fopen = (FILE* (*)(const char *, const char *))
dlsym(RTLD_NEXT, "fopen");
}
if (debug) fprintf(stderr, "FOPEN: %s %s\n", pathname, mode);
if (root) {
return(real_fopen(pathname, mode));
}
str = (char *) pathname;
if (strstr(pathname, "/var/log") == pathname) {
str = tmpdir_path(pathname);
if (debug) fprintf(stderr, "FOPEN: -> %s\n", str);
}
}
#define RETURN0 if (debug) \
{fprintf(stderr, "IOCTL: covered %d 0x%x\n", fd, req);} return 0;
#define RETURN1 if (debug) \
{fprintf(stderr, "IOCTL: covered %d 0x%x\n", fd, req);} return -1;
int ioctl(int fd, int req, void *ptr) {
static int closed_xf86Info_consoleFd = 0;
static int (*real_ioctl)(int, int , void *) = NULL;
CHECKIT
if (! real_ioctl) {
real_ioctl = (int (*)(int, int , void *))
dlsym(RTLD_NEXT, "open");
}
if (debug) fprintf(stderr, "IOCTL: %d 0x%x %p\n", fd, req, ptr);
/* based on xorg-x11-6.8.1-dualhead.patch */
if (req == VT_GETMODE) {
/* close(xf86Info.consoleFd) */
if (0 && ! closed_xf86Info_consoleFd) {
/* I think better not to close it... */
close(fd);
closed_xf86Info_consoleFd = 1;
}
RETURN0
} else if (req == VT_SETMODE) {
RETURN0
} else if (req == VT_GETSTATE) {
RETURN0
} else if (req == KDSETMODE) {
RETURN0
} else if (req == KDSETLED) {
RETURN0
} else if (req == KDGKBMODE) {
RETURN0
} else if (req == VT_ACTIVATE) {
RETURN0
} else if (req == VT_WAITACTIVE) {
RETURN0
} else if (req == VT_RELDISP) {
if (ptr == (void *) 1) {
RETURN1
} else if (ptr == (void *) VT_ACKACQ) {
RETURN0
}
}
return(real_ioctl(fd, req, ptr));
}
typedef void (*sighandler_t)(int);
#define SIGUSR1 10
#define SIG_DFL ((sighandler_t)0)
sighandler_t signal(int signum, sighandler_t handler) {
static sighandler_t (*real_signal)(int, sighandler_t) = NULL;
CHECKIT
if (! real_signal) {
real_signal = (sighandler_t (*)(int, sighandler_t))
dlsym(RTLD_NEXT, "signal");
}
if (debug) fprintf(stderr, "SIGNAL: %d %p\n", signum, handler);
if (signum == SIGUSR1) {
if (debug) fprintf(stderr, "SIGNAL: skip SIGUSR1\n");
return SIG_DFL;
}
return(real_signal(signum, handler));
}
int close(int fd) {
static int (*real_close)(int) = NULL;
CHECKIT
if (! real_close) {
real_close = (int (*)(int)) dlsym(RTLD_NEXT, "close");
}
if (debug) fprintf(stderr, "CLOSE: %d\n", fd);
if (! root) {
if (fd < 256) {
devs[fd][0] = '\0';
}
}
return(real_close(fd));
}
struct stat {
int foo;
};
int stat(const char *path, struct stat *buf) {
static int (*real_stat)(const char *, struct stat *) = NULL;
CHECKIT
if (! real_stat) {
real_stat = (int (*)(const char *, struct stat *))
dlsym(RTLD_NEXT, "stat");
}
if (debug) fprintf(stderr, "STAT: %s\n", path);
return(real_stat(path, buf));
}
int stat64(const char *path, struct stat *buf) {
static int (*real_stat64)(const char *, struct stat *) = NULL;
CHECKIT
if (! real_stat64) {
real_stat64 = (int (*)(const char *, struct stat *))
dlsym(RTLD_NEXT, "stat64");
}
if (debug) fprintf(stderr, "STAT64: %s\n", path);
return(real_stat64(path, buf));
}
/*
* Note: the following just call the real function if root is
* true. They will be used if -nonroot is ever figured out.
*/
int chown(const char *path, uid_t owner, gid_t group) {
static int (*real_chown)(const char *, uid_t, gid_t) = NULL;
CHECKIT
if (! real_chown) {
real_chown = (int (*)(const char *, uid_t, gid_t))
dlsym(RTLD_NEXT, "chown");
}
if (root) {
return(real_chown(path, owner, group));
}
if (debug) fprintf(stderr, "CHOWN: %s %d %d\n", path, owner, group);
if (strstr(path, "/dev") == path) {
if (debug) fprintf(stderr, "CHOWN: return 0\n");
return 0;
}
return(real_chown(path, owner, group));
}
int ioperm(unsigned long from, unsigned long num, int turn_on) {
static int (*real_ioperm)(unsigned long, unsigned long, int) = NULL;
CHECKIT
if (! real_ioperm) {
real_ioperm = (int (*)(unsigned long, unsigned long, int))
dlsym(RTLD_NEXT, "ioperm");
}
if (root) {
return(real_ioperm(from, num, turn_on));
}
return 0;
}
int iopl(int level) {
static int (*real_iopl)(int) = NULL;
CHECKIT
if (! real_iopl) {
real_iopl = (int (*)(int)) dlsym(RTLD_NEXT, "iopl");
}
if (root) {
return(real_iopl(level));
}
return 0;
}
uid_t getuid(void) {
static uid_t (*real_getuid)(void) = NULL;
CHECKIT
if (! real_getuid) {
real_getuid = (uid_t (*)(void)) dlsym(RTLD_NEXT, "getuid");
}
if (root) {
return(real_getuid());
}
if (debug) fprintf(stderr, "GETUID: 0\n");
return 0;
}
uid_t geteuid(void) {
static uid_t (*real_geteuid)(void) = NULL;
CHECKIT
if (! real_geteuid) {
real_geteuid = (uid_t (*)(void)) dlsym(RTLD_NEXT, "geteuid");
}
if (root) {
return(real_geteuid());
}
if (debug) fprintf(stderr, "GETEUID: 0\n");
return 0;
}
uid_t getuid32(void) {
static uid_t (*real_getuid32)(void) = NULL;
CHECKIT
if (! real_getuid32) {
real_getuid32 = (uid_t (*)(void)) dlsym(RTLD_NEXT, "getuid32");
}
if (root) {
return(real_getuid32());
}
if (debug) fprintf(stderr, "GETUID32: 0\n");
return 0;
}
uid_t geteuid32(void) {
static uid_t (*real_geteuid32)(void) = NULL;
CHECKIT
if (! real_geteuid32) {
real_geteuid32 = (uid_t (*)(void)) dlsym(RTLD_NEXT, "geteuid32");
}
if (root) {
return(real_geteuid32());
}
if (debug) fprintf(stderr, "GETEUID32: 0\n");
return 0;
}
gid_t getgid(void) {
static gid_t (*real_getgid)(void) = NULL;
CHECKIT
if (! real_getgid) {
real_getgid = (gid_t (*)(void)) dlsym(RTLD_NEXT, "getgid");
}
if (root) {
return(real_getgid());
}
if (debug) fprintf(stderr, "GETGID: 0\n");
return 0;
}
gid_t getegid(void) {
static gid_t (*real_getegid)(void) = NULL;
CHECKIT
if (! real_getegid) {
real_getegid = (gid_t (*)(void)) dlsym(RTLD_NEXT, "getegid");
}
if (root) {
return(real_getegid());
}
if (debug) fprintf(stderr, "GETEGID: 0\n");
return 0;
}
gid_t getgid32(void) {
static gid_t (*real_getgid32)(void) = NULL;
CHECKIT
if (! real_getgid32) {
real_getgid32 = (gid_t (*)(void)) dlsym(RTLD_NEXT, "getgid32");
}
if (root) {
return(real_getgid32());
}
if (debug) fprintf(stderr, "GETGID32: 0\n");
return 0;
}
gid_t getegid32(void) {
static gid_t (*real_getegid32)(void) = NULL;
CHECKIT
if (! real_getegid32) {
real_getegid32 = (gid_t (*)(void)) dlsym(RTLD_NEXT, "getegid32");
}
if (root) {
return(real_getegid32());
}
if (debug) fprintf(stderr, "GETEGID32: 0\n");
return 0;
}
#if 0
int xf86PathIsSafe(char *path) {
fprintf(stderr, "xf86pathIsSafe: %s\n", path);
return 1;
}
#endif
#if 0
int strcmp(const char *s1, const char *s2) {
static int (*real_strcmp)(const char *, const char *) = NULL;
CHECKIT
if (! real_strcmp) {
real_strcmp = (int (*)(const char *, const char *)) dlsym(RTLD_NEXT, "strcmp");
}
if (debug) fprintf(stderr, "STRCMP: '%s' '%s'\n", s1, s2);
return(real_strcmp(s1, s2));
}
#endif
#code_end
}