#!/bin/sh
#
# upload (c) Geoffrey T. Falk, November 1998
# Upload changed files via rcp automatically
# Requires gnutar for incremental backups.
#
# USAGE: upload [user@]remote.host local_path [remote_path]
# If remote_path is omitted, defaults to local_path
# If user is omitted, defaults to local username


# Need to clean up lockfiles, etc. on abort
trap abort 2

REMOTE_TAR=/usr/bin/tar


# parse arguments (two usage forms)
if [ $# -ne 2 -a $# -ne 3 ]; then
  echo "usage: $0 [user@]remote.host local_dir [remote_dir]" 1>&2
  exit 2
fi

cleanup() {
  rm -f .gin.old .lock "$TARBALL"
}

abort() {
  echo "$@" 1>&2
  if [ -f .gin.old ]; then
    mv -f .gin.old .gin
  fi
  cleanup
  exit 1
}

local_dir="$2"

if [ ! -d "$local_dir" ]; then
  echo "$local_dir: Invalid directory"	1>&2
  exit 2
fi

# extract remote user, host if using "@" notation
arg1=`echo $1 | awk -F@ '{printf "%s", $2}'`

if [ -z "$arg1" ]; then		# no "@" supplied
  remote_user="$USER"
  remote_host="$1"
else
  remote_user=`echo $1 | awk -F@ '{printf "%s", $1}'`
  remote_host="$arg1"
fi

if [ $# -eq 3 ]; then
  remote_dir="$3"
else
  remote_dir="$2"
fi

TARBALL="/tmp/`echo $local_dir | tr /~ __`_$$.tar.gz"
REMOTE_TARBALL="~${remote_user}/tmp/`echo $remote_dir | tr /~ __`.tar.gz"
# (remote user must have a "tmp" directory in his home directory)

cd "$local_dir"

# Minor bug: There is a race condition between the following if/else clauses,
# if two copies of upload are run simultaneously. It is not worthwhile to
# fix this.
if [ -f .lock ]; then
  echo -n "$local_dir locked by PID "	1>&2
  cat .lock				1>&2
  echo "; aborting"			1>&2
  abort
else
  echo -n $$ > .lock
fi

# files/directories not to include in the transfer (must exist)
if [ ! -f .exclude ]; then
  cat > .exclude << EOF
.exclude
.lock
EOF
fi

# GNU-format incremental information file stored at $local_dir/.gin
if [ ! -f .gin ]; then
  touch .gin
fi

cp -p .gin .gin.old	# preserve incremental data if upload aborts

# create the tarfile of changed files
tar -cvzf "$TARBALL" -g .gin -X .exclude .

# blast tarfile to remote machine
scp "$TARBALL" "$remote_user"@"$remote_host":"$REMOTE_TARBALL"

if [ $? != 0 ]; then
  abort "Upload failed"
fi

# extract tarfile on remote machine
ssh "$remote_host" -l "$remote_user" \
	"${REMOTE_TAR}" -xzf "$REMOTE_TARBALL" -C "$remote_dir"

if [ $? != 0 ]; then
  abort "Remote extraction failed"
fi

cleanup
exit 0