libgocryptfs/contrib/maxlen.bash
Jakob Unterwurzacher 9ac77d42d1 contrib/maxlen.bash: also test dir and path length
Move the script from tests to contrib as it may now
be useful to somebody else.

https://github.com/rfjakob/gocryptfs/issues/552
2021-06-20 18:09:21 +02:00

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#!/bin/bash
#
# Find out the maximum supported filename length and print it.
#
# Part of the gocryptfs test suite
# https://nuetzlich.net/gocryptfs/
set -eu
MYNAME=$(basename "$0")
if [[ $# -ne 1 || $1 == -* ]]; then
echo "Usage: $MYNAME DIRECTORY"
exit 1
fi
cd "$1"
echo "Testing $PWD"
echo -n " Maximum filename length: "
# Add one character at a time until we hit an error
NAME=""
while true ; do
NEXT="${NAME}x"
if [[ -e $NEXT ]]; then
echo "error: file $NEXT already exists"
exit 1
fi
touch $NEXT 2> /dev/null || break
rm $NEXT
NAME="$NEXT"
done
echo "${#NAME}"
echo -n " Maximum dirname length: "
# Add one character at a time until we hit an error
NAME=""
while true ; do
NEXT="${NAME}x"
mkdir $NEXT 2> /dev/null || break
rmdir $NEXT
NAME="$NEXT"
done
MAX_DIRNAME=${#NAME}
echo "${#NAME}"
for CHARS_PER_SUBDIR in 1 10 100 $MAX_DIRNAME ; do
echo -n " Maximum path length with $(printf %3d $CHARS_PER_SUBDIR) chars per subdir: "
# Trick from https://stackoverflow.com/a/5349842/1380267
SUBDIR=$(printf 'x%.0s' $(seq 1 $CHARS_PER_SUBDIR))
mkdir "$SUBDIR"
P=$SUBDIR
# Create a deep path, one $SUBDIR at a time, until we hit an error
while true ; do
NEXT="$P/$SUBDIR"
mkdir "$NEXT" 2> /dev/null || break
P=$NEXT
echo -n -e "\b\b\b\b"
printf %4d ${#P}
done
# Then add one character at a time until we hit an error
NAME=""
while true ; do
NEXT="${NAME}x"
touch "$P/$NEXT" 2> /dev/null || break
NAME=$NEXT
done
if [[ $NAME != "" ]] ; then
P=$P/$NAME
fi
echo -n -e "\b\b\b\b"
printf %4d ${#P}
echo
rm -R "$SUBDIR"
done