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Wind, fire, all that kind of thing!

2012-08-29

Linker Errors When Building Xlock on Debian

When building xlockmore (version 5.39) on one of my Debian boxes I encountered two linker issues, one with libxext, the other with libcrypt. Both issues persisted even after running configure with the --without-ext and --without-crypt options. WTF?! Why would anyone with at least half a brain provide --without-FEATURE options for apparently required features?


Anyway, first error was ld reporting that it couldn't find libxext:

gcc -g -O2 -o ../xlock/xlock ../xlock/xlock.o ../xlock/passwd.o ../xlock/resource.o ../xlock/parsecmd.o ../xlock/util.o ../xlock/logout.o ../xlock/mode.o ../xlock/xlockimage.o ../xlock/ras.o ../xlock/xbm.o ../xlock/vis.o ../xlock/visgl.o ../xlock/color.o ../xlock/random.o ../xlock/iostuff.o ../xlock/automata.o ../xlock/spline.o ../xlock/sound.o ../xlock/erase.o ../xlock/magick.o ../xlock/vtlock.o ../xlock/vtlock_proc.o anemone.o ant.o ant3d.o apollonian.o ball.o bat.o blot.o bouboule.o bounce.o braid.o bubble.o bug.o clock.o coral.o crystal.o daisy.o dclock.o decay.o deco.o deluxe.o demon.o dilemma.o discrete.o dragon.o drift.o euler2d.o eyes.o fadeplot.o fiberlamp.o flag.o flame.o flow.o forest.o fzort.o galaxy.o goop.o grav.o helix.o hop.o hyper.o ico.o ifs.o image.o juggle.o julia.o kaleid.o kumppa.o laser.o life.o life1d.o life3d.o lightning.o lisa.o lissie.o loop.o lyapunov.o mandelbrot.o marquee.o matrix.o maze.o mountain.o munch.o nose.o pacman.o penrose.o petal.o petri.o polyominoes.o puzzle.o pyro.o pyro2.o qix.o rain.o roll.o rotor.o scooter.o shape.o sierpinski.o slip.o space.o sphere.o spiral.o spline.o star.o starfish.o strange.o swarm.o swirl.o t3d.o tetris.o thornbird.o tik_tak.o toneclock.o triangle.o tube.o turtle.o vines.o voters.o wator.o wire.o world.o worm.o xcl.o xjack.o solitaire.o bomb.o blank.o random.o -lSM -lICE -lX11 -lXext -lm

/usr/bin/ld: cannot find -lXext

collect2: error: ld returned 1 exit status

make[1]: *** [../xlock/xlock] Error 1

Installing the respective development package resolved this issue.

apt-get install libxext-dev

The second issue were a couple undefined references to crypt(3) in passwd.c:

../xlock/passwd.o: In function `gpasskey':

/usr/src/xlockmore-5.39_test/xlock/passwd.c:692: undefined reference to `crypt'

../xlock/passwd.o: In function `checkPasswd':

/usr/src/xlockmore-5.39_test/xlock/passwd.c:1396: undefined reference to `crypt'

/usr/src/xlockmore-5.39_test/xlock/passwd.c:1415: undefined reference to `crypt'

collect2: error: ld returned 1 exit status

make[1]: *** [../xlock/xlock] Error 1

crypt(3) is provided by the glibc development package (libc6-dev), which was already installed, so this time the reason had to be something other than a missing package. Looking at the command that raised the error I noticed that -lcrypt was missing from the list of libraries:

gcc -g -O2 -o ../xlock/xlock ../xlock/xlock.o ../xlock/passwd.o ../xlock/resource.o ../xlock/parsecmd.o ../xlock/util.o ../xlock/logout.o ../xlock/mode.o ../xlock/xlockimage.o ../xlock/ras.o ../xlock/xbm.o ../xlock/vis.o ../xlock/visgl.o ../xlock/color.o ../xlock/random.o ../xlock/iostuff.o ../xlock/automata.o ../xlock/spline.o ../xlock/sound.o ../xlock/erase.o ../xlock/magick.o ../xlock/vtlock.o ../xlock/vtlock_proc.o anemone.o ant.o ant3d.o apollonian.o ball.o bat.o blot.o bouboule.o bounce.o braid.o bubble.o bug.o clock.o coral.o crystal.o daisy.o dclock.o decay.o deco.o deluxe.o demon.o dilemma.o discrete.o dragon.o drift.o euler2d.o eyes.o fadeplot.o fiberlamp.o flag.o flame.o flow.o forest.o fzort.o galaxy.o goop.o grav.o helix.o hop.o hyper.o ico.o ifs.o image.o juggle.o julia.o kaleid.o kumppa.o laser.o life.o life1d.o life3d.o lightning.o lisa.o lissie.o loop.o lyapunov.o mandelbrot.o marquee.o matrix.o maze.o mountain.o munch.o nose.o pacman.o penrose.o petal.o petri.o polyominoes.o puzzle.o pyro.o pyro2.o qix.o rain.o roll.o rotor.o scooter.o shape.o sierpinski.o slip.o space.o sphere.o spiral.o spline.o star.o starfish.o strange.o swarm.o swirl.o t3d.o tetris.o thornbird.o tik_tak.o toneclock.o triangle.o tube.o turtle.o vines.o voters.o wator.o wire.o world.o worm.o xcl.o xjack.o solitaire.o bomb.o blank.o random.o -lSM -lICE -lX11 -lXext -lm

configure defines these libraries in the variable ${XLOCKLIBS}, so I tried injecting -lcrypt by pre-defining that variable:

XLOCKLIBS=-lcrypt ./configure ...

With this, the xlock binary was built without any further issues.

One other problem presented itself on NIS clients, though. NIS users were only able to unlock a locked screen with their password after I had changed the mode of the xlock binary from SGID to SUID:

chmod u+s,g-s $(which xlock)

Posted 02:03 [permalink]