[SOLVED] Detect CD tray status

psionl0 · 02-18-2013, 10:23 PM

Quote:

Originally Posted by volkerdi

Here's a simple C program:

Compile it with gcc, call it trayopen. Then you can use it in scripts based on the exit code, like so:

./trayopen /dev/sr0 && echo tray is open || echo tray is closed

If you want trayopen to be a system-wide app you could copy the executable to /usr/local/bin.

Better still, you could make a package out of it. Here is a simple script that will compile the C program and put the output into a package (note: there must be a space after the \ in the slack-desc section).

Code:

#!/bin/sh

# Slackware build script for trayopen


PRGNAM=trayopen
VERSION=${VERSION:-1.0}
BUILD=${BUILD:-1}
TAG=${TAG:-_custom}

# Automatically determine the architecture we're building on:
if [ -z "$ARCH" ]; then
  case "$( uname -m )" in
    i?86) ARCH=i486 ;;
    arm*) ARCH=arm ;;
    # Unless $ARCH is already set, use uname -m for all other archs:
       *) ARCH=$( uname -m ) ;;
  esac
fi

CWD=$(pwd)
PKG=$CWD/package-$PRGNAM

if [ "$ARCH" = "i486" ]; then
  SLKCFLAGS="-O2 -march=i486 -mtune=i686"
  LIBDIRSUFFIX=""
elif [ "$ARCH" = "i686" ]; then
  SLKCFLAGS="-O2 -march=i686 -mtune=i686"
  LIBDIRSUFFIX=""
elif [ "$ARCH" = "x86_64" ]; then
  SLKCFLAGS="-O2 -fPIC"
  LIBDIRSUFFIX="64"
else
  SLKCFLAGS="-O2"
  LIBDIRSUFFIX=""
fi

set -e # Exit on most errors

rm -rf $PKG
mkdir -p $PKG

# Compile the application and install it into the $PKG directory
gcc -o trayopen trayopen.c
mkdir -p $PKG/usr/bin
cp -a trayopen $PKG/usr/bin

# Copy the slack-desc into $PKG/install
mkdir -p $PKG/install

cat > $PKG/install/slack-desc <<_EOF
trayopen: trayopen 
trayopen:
trayopen: A utility that returns the open/closed status
trayopen: of the CD tray.
trayopen:
trayopen: It can be used in a script such as:
trayopen: trayopen /dev/sr0 && echo tray is open \ 
trayopen: || echo tray is closed
trayopen:
trayopen:
trayopen:
_EOF

# Make the package
cd $PKG
/sbin/makepkg -l y -c n $CWD/$PRGNAM-$VERSION-$ARCH-$BUILD$TAG.${PKGTYPE:-tgz}

GazL · 02-19-2013, 05:10 AM

Quote:

Originally Posted by Woodsman

Revision 3 works on all systems here.

Good job!

Perhaps if other people with quirky optical drives find the patch useful that might provide some motivation.

As I said above, though it works, I didn't care for the solution in v3 as it felt half-done. I've had a final stab at it.
I had the inspiration that if we do a second call of CDROM_DRIVE_STATUS after the first CDROMEJECT and if it returns CDS_TRAY_OPEN then we know that there is no need to play that ugly elapsed time based "was it open or closed?" guessing game. Simple really. I don't know why it didn't occur to me from the start.

Unlike V3 this one feels 'right' to me and if Pat wanted to include it I wouldn't have any concerns.

Anyway, job done. I enjoyed that little puzzle.