update installer to warn about non linux

docker/Dockerfile

@@ -1,19 +1,18 @@
 FROM ubuntu:16.04
 
-# minimal system basics
+# system basics
 RUN apt-get update
-RUN apt-get -y install git curl python
+RUN apt-get -y install build-essential git curl python python-virtualenv python-dev
 
 # fetch qira
-RUN git clone https://github.com/geohot/qira.git
+RUN git clone https://github.com/geohot/qira.git --depth=1
 WORKDIR /qira
 
 # build qemu
-RUN apt-get -y install build-essential pkg-config zlib1g-dev libglib2.0-dev libpixman-1-dev
+RUN apt-get -y install pkg-config zlib1g-dev libglib2.0-dev libpixman-1-dev
 RUN cd tracers && ./qemu_build.sh
 
 # install python packages and link qira
-RUN apt-get -y install python python-virtualenv python-dev
 RUN virtualenv venv
 RUN bash -c 'source venv/bin/activate && pip install --upgrade pip'
 RUN bash -c 'source venv/bin/activate && pip install --upgrade -r requirements.txt'

install.sh

@@ -9,13 +9,20 @@ else
 fi
 
 # build qemu
-if [ $(tracers/qemu/qira-i386 > /dev/null; echo $?) == 1 ]; then
+if [[ "$(uname)" == 'Linux' ]]; then
+  if [ $(tracers/qemu/qira-i386 > /dev/null; echo $?) == 1 ]; then
     echo "QIRA QEMU appears to run okay"
-else
+  else
     echo "building QEMU"
     cd tracers
     ./qemu_build.sh
     cd ../
+  fi
+else
+  echo "QEMU user only works on Linux."
+  echo "While the rest of QIRA will run, you cannot run binaries."
+  echo "This is due to QEMU user forwarding the syscalls to the kernel."
+  echo "See other backends in qira/tracers, PIN may work on Windows and OS X"
 fi
 
 echo "building python venv"

run_tests.sh

@@ -13,7 +13,7 @@ source venv/bin/activate
 nosetests -v -s
 
 # integration test
-qira qira_tests/bin/loop &
+./qira qira_tests/bin/loop &
 QIRA_PID=$!
 trap "kill $QIRA_PID" EXIT
 echo "qira pid is $QIRA_PID"