install_procmap

#!/bin/bash
# Part of the 'procmap' project, a utility to show the kernel and/or user
# virtual address space of any given process.
# This is the initial 'install' script.
# Major advantages of this approach include:
#  1. Regular users can browse their own process's user VAS (no root access reqd)
#  2. The procmap kernel module needs to be run and collect details only once,
#     at install time.
#
# Author:
# Kaiwan N Billimoria
# kaiwan -at- kaiwantech -dot- com
# kaiwan -dot- billimoria -at- gmail -dot- com
# kaiwanTECH
#
# License: MIT.
 
# Turn on unofficial Bash 'strict mode'! V useful
# "Convert many kinds of hidden, intermittent, or subtle bugs into immediate, glaringly obvious errors"
# ref: http://redsymbol.net/articles/unofficial-bash-strict-mode/
set -euo pipefail

name=$(basename $0)

# set the common paths
PATH=${PATH}:/sbin/:/usr/sbin/:/usr/bin/:/bin/
export TERM=xterm-256color
# sanitize the environment before run
[[ "$(env | sed -r -e '/^(PWD|SHLVL|_)=/d')" ]] && {
  export TERM=xterm-256color
 # exec -c "$0" "$@"
}

PDIR=$(which $0)
[ -z "${PDIR}" ] && PDIR=$(dirname $0)  # true if procmap isn't in PATH
export PFX=$(dirname ${PDIR})    # dir in which this script and tools reside

source config || {
 echo "${name}: fatal: could not source file 'config', aborting..."
 exit 1
}

VERBOSE=1
DEBUG=0

vecho()
{
  [[ ${VERBOSE} -eq 1 ]] && echo "[v] $*"
}
decho()
{
  [[ ${DEBUG} -eq 1 ]] && echo "[d] $*"
}
die()
{
echo >&2 "${name}: ***FATAL ERROR***
Error detail follows:
$*" ; exit 1
}

# build_lkm()
# (Re)build the LKM - Loadable Kernel Module for this project
build_lkm()
{
 echo "[i] kernel: building the procmap kernel module now..."

 # kernel headers?
 [ ! -e /lib/modules/"$(uname -r)"/build ] && \
    die "
Suitable build env for kernel modules is missing!
Pl install the Linux kernel headers (via the appropriate package). If you
cannot install a 'kernel headers' package (perhaps you're running a custom
built kernel), then you will need to cross-compile the procmap kernel module
on your host and copy it across to the target device.

Pl see this project's
README.md file for details: https://github.com/kaiwan/procmap#procmap
(Plus the section 'IMPORTANT: Running procmap on systems other than x86_64'
 https://github.com/kaiwan/procmap#important-running-procmap-on-systems-other-than-x86_64)."

 cd procmap_kernel || die "cd procmap_kernel failed"
 make clean >/dev/null 2>&1 || true
 make >/dev/null 2>&1 || die "kernel module \"${KMOD}\" build failed, aborting..."
 if [ ! -s ${KMOD}.ko ] ; then
    die "kernel module \"${KMOD}\" not generated? aborting..."
 fi
 vecho " kernel: LKM built"
} # end build_lkm()

# init_kernel_lkm_get_details()
init_kernel_lkm_get_details()
{
#set +x
  vecho "kernel: init kernel LKM and get details:"
  if [ ! -d ${DBGFS_LOC} ] ; then
 	die "kernel debugfs not supported or mounted? aborting..."
  else
    vecho " debugfs location verfied"
  fi

  #TOP=$(pwd)

  if [ ! -s ${KMOD}.ko -o ${KMOD}.c -nt ${KMOD}.ko ] ; then
     build_lkm
  fi

  # Ok, the kernel module is there, lets insert it!
  #ls -l ${KMOD}.ko

  rmmod ${KMOD} 2>/dev/null || true   # rm any stale instance
  insmod ./${KMOD}.ko || {
	echo "${name}: insmod(8) on kernel module \"${KMOD}\" failed, will rebuild and retry now..."
        build_lkm
	insmod ./${KMOD}.ko || return
  }
  # Whoa! with set -o pipefail enabled AND using grep -q, all kinds of crazy s*it
  # Practical sol: do NOT use -q, redirect stdout & stderr to null dev!
  # ref: https://stackoverflow.com/questions/19120263/why-exit-code-141-with-grep-q
  lsmod | egrep -w "^${KMOD}" >/dev/null 2>&1
  [ $? -ne 0 ] && die "insmod(8) on kernel module \"${KMOD}\" failed? aborting..."
  vecho " LKM inserted into kernel"
  ls ${DBGFS_LOC}/${KMOD}/${DBGFS_FILENAME} >/dev/null 2>&1 || {
	 rmmod ${KMOD}
	 die "required debugfs file not present? aborting..."
  }
  vecho " debugfs file present"
} # end init_kernel_lkm_get_details()

#--- Setup the one-time kernel-details file
setup_kernel_dtl_file()
{
# Finally! generate the kernel seg details
[[ ! -d ${REPORT_DIR} ]] && mkdir -p ${REPORT_DIR} #|| die "failed creating procmap report dir"
TEMP_KSEGFILE=${REPORT_DIR}/$(basename ${KSEGFILE}).$$
#echo "TEMP_KSEGFILE = $TEMP_KSEGFILE"
cat ${DBGFS_LOC}/${KMOD}/${DBGFS_FILENAME} > ${TEMP_KSEGFILE}
# CSV fmt of ${KSEGFILE}.$$
#  start_kva,end_kva,mode,name-of-region
# Must numerically sort the kernel mappings by descending kva (2nd field)
sort -t"," -k2n -r ${TEMP_KSEGFILE} > ${KSEGFILE}
chmod 0444 ${KSEGFILE}

rm -f ${TEMP_KSEGFILE} || true
echo "[i] procmap: one-time kernel details placed here:${KSEGFILE}

TIP:
This kernel-detail file - ${KSEGFILE} - is ALWAYS required by procmap,
even when viewing only the user virtual address space of any given process.
Thus, pl back it up, so that you can restore it in this location if required
in future."

decho "kseg dtl:
$(cat ${KSEGFILE})" || true
} # end setup_kernel_dtl_file()


#--- 'main'
[[ -f ${KSEGFILE} ]] && {
  echo "WARNING! procmap seems to be already be installed on this system!
Would you like to re-install it (overwriting the original kernel-detail file (${KSEGFILE})?
[y/n]"
  read re
  [[ "${re}" = "y" ||  "${re}" = "Y" ]] || exit 0
}

[[ $(id -u) -ne 0 ]] && die "requires root"
DIR=$(pwd)
init_kernel_lkm_get_details || true
setup_kernel_dtl_file
rmmod ${KMOD} || true
cd ${DIR}
exit 0