Backport changes from apptainer image rework

Makefile

@@ -17,7 +17,7 @@ GID := $(shell id -g)
 p4iab.tar.gz: .docker_build
 	"$(DOCKER)" save p4iab:latest | gzip > "$@"
 
-p4iab.sif: p4iab.def p4iab.tar.gz
+p4iab.sif: p4iab.def .docker_build
 	sudo "$(APPTAINER)" build "$@" "$<"
 	sudo chown $(UID):$(GID) "$@"
 

README.md

@@ -27,6 +27,19 @@ this container also has a few other advantages:
 5. When converted into a Apptainer SIF, it can be launched as a single binary
    executable.
 
+User Tools
+----------
+
+The containers are built with several additional user tools already in place,
+including but not limited to:
+
+1. `vim`/`emacs`: text editing.
+2. `git`: version control.
+3. `tmux`: terminal multiplexing.
+3. `tshark`/`termshark`/`tcpdump`: packets inspection.
+4. `htop`: visual overview of processes.
+5. `man`/`less`: documentation support.
+
 How to Use
 ----------
 
@@ -34,9 +47,9 @@ There are two ways of launching P4-in-a-Bottle:
 
 ### Apptainer
 
-Apptainer is a container runtime by Sylabs developed specificly for software
-that require low-level access to hardware (i.e. NVIDIA drivers, network
-devices). This is great for P4-in-a-Bottle, since Mininet requires access to
+Apptainer is a new container runtime developed specificly for software that
+require low-level access to hardware (i.e. NVIDIA drivers, network devices,
+etc). This is great for P4-in-a-Bottle, since Mininet requires access to
 networking kernel components to work.
 
 Unfortunately, Apptainer only works natively on Linux, so if you're on Mac or
@@ -54,8 +67,8 @@ To use P4-in-a-Bottle with Apptainer:
 
 ### Docker
 
-If you are stuck with docker, don't panic! The instructions are longer but
-everything should still work.
+If you are stuck with docker, don't panic! The instructions are slightly more
+complicated but everything should still work.
 1. Install docker on your system. This should be pretty self-explanatory.
 2. Clone and cd into this repository.
 3. Download a pre-built image
@@ -65,6 +78,9 @@ everything should still work.
 5. Run `make run`. A shared directory `shared/` will be created to allow
    you to move files between the container and your system.
 
+Regardless of which method you run the container, you will be dropped into a
+shell with the user P4. The password for the P4 user account is simply `p4`.
+
 
 Building from Source
 --------------------

p4iab.def

@@ -1,5 +1,5 @@
-BootStrap: docker-archive
-From: p4iab.tar.gz
+BootStrap: docker-daemon
+From: p4iab:latest
 
 %files
     scripts/p4iab_singularity_entry.sh /usr/bin/p4iab_singularity_entry.sh