BUILDING

BUILD INSTRUCTIONS:
- Android SDK and NDK
- 7Zip command line '7z'

# ############################################################################
# Typically in ~/.bashrc
# ############################################################################
export JAVA_HOME=/cygdrive/c/d/jdk/
export PATH=${JAVA_HOME}/bin:${PATH}

SDK=/cygdrive/c/d/sdk
NDK=${SDK}/ndk/26.2.11394342

export TOOLCHAIN=${NDK}/toolchains/llvm/prebuilt/windows-x86_64
export PATH=${SDK}/platform-tools:${TOOLCHAIN}/bin:${PATH}

# ############################################################################
# Step 1 - Setting up the toolchain
# ############################################################################

# From the root dir with the tarball
export SRC_ROOT=`pwd`

# TOOLCHAIN is expected to point to your ndk environment toolchain.
[ -n "${TOOLCHAIN}" ] || { echo "TOOLCHAIN must be set"; exit 1; }

if [ ! -d "$NDK" ]; then
  echo "$NDK does not exist."
  return
fi


# Set this to your minSdkVersion.
export API=26

echo "Only choose one of these, depending on your device..."
echo "1) aarch64-linux-android ... which is most likely this one"
echo "2) armv7a-linux-androideabi"
echo "3) i686-linux-android"
echo "4) x86_64-linux-android"
echo -n "Select target: "
read REPLY
case $REPLY in
    "1")
        export TARGET=aarch64-linux-android
        ;;
    "2")
        export TARGET=armv7a-linux-androideabi
        ;;
    "3")
        export TARGET=i686-linux-android
        ;;
    "4")
        export TARGET=x86_64-linux-android
        ;;
esac

echo "TARGET=${TARGET}"
echo "API=${API}"

export AR=${TOOLCHAIN}/bin/llvm-ar
export CC=${TOOLCHAIN}/bin/${TARGET}${API}-clang
export AS=${CC}
export CXX=${TOOLCHAIN}/bin/${TARGET}${API}-clang++
export LD=${TOOLCHAIN}/bin/ld
export RANLIB=${TOOLCHAIN}/bin/llvm-ranlib
export STRIP=${TOOLCHAIN}/bin/llvm-strip

# content for ".gitattributes"
export GATRR="* text eol=lf\n*.txt text\n*.png binary\n"

# ############################################################################
# Step 2.1 - RSYNC - https://rsync.samba.org/
# https://download.samba.org/pub/rsync/src/rsync-3.3.0.tar.gz
# ############################################################################
# replace base filename in the below string after download:
export RSYNC_VERSION="rsync-3.3.0"

cd ${SRC_ROOT}
7z x -so ${RSYNC_VERSION}* | tar xf -
# remove broken and/or unneeded rsync symlink
rm ${RSYNC_VERSION}/md2man
# rename the directory so we don't need to change the git remote names
export RSYNC="upstream-rsync"

# Prep rsync
mkdir -p ${RSYNC}/app/src/main/cpp/
mv ${RSYNC_VERSION} ${RSYNC}/app/src/main/cpp/rsync
cd ${RSYNC}
echo -e "${GATRR}" >.gitattributes
git init .
git add * .gitattributes
git commit -a -m "${RSYNC_VERSION}"
cd ${SRC_ROOT}

# Configure rsync
cd ${SRC_ROOT}/${RSYNC}/app/src/main/cpp/rsync
./configure --host $TARGET --disable-openssl --disable-xxhash --disable-zstd --disable-lz4 \
            --disable-md2man --disable-roll-simd --disable-md5-asm --disable-roll-asm \
            --enable-largefile
cd ${SRC_ROOT}

# Add remote: "upstream-rsync" pointing to the location used above
git remote add upstream-rsync c:/tmp/sshd4a-tarballs/upstream-rsync
git fetch upstream-rsync
git merge --allow-unrelated-histories upstream-rsync/dev

#    All changes are (should be) marked with SSHD4A_*
#    Merge and solve conflicts as usual.

cd ${SRC_ROOT}/${RSYNC}/app/src/main/cpp/
./prebuild-rsyn.sh

#    Update gradle.build: android.defaultConfig buildConfigField("String", "VERSION_RSYNC"...
#    Commit and build...

# ############################################################################
#  Step 2.2 - OPENSSH - https://github.com/openssh/openssh-portable
# https://mirror.ox.ac.uk/pub/OpenBSD/OpenSSH/portable/openssh-9.7p1.tar.gz
# ############################################################################
# replace base filename in the below string after download:
export OPENSSH_VERSION="openssh-9.7p1"

cd ${SRC_ROOT}
7z x -so ${OPENSSH_VERSION}* | tar xf -
# rename the directory so we don't need to change the git remote names
export OPENSSH="upstream-openssh"

# Prep openssh
mkdir -p ${OPENSSH}/app/src/main/cpp/
mv ${OPENSSH_VERSION} ${OPENSSH}/app/src/main/cpp/openssh
cd ${OPENSSH}
echo -e "${GATRR}" >.gitattributes
git init .
git add * .gitattributes
git commit -a -m "${OPENSSH_VERSION}"
cd ${SRC_ROOT}

# Configure openssh
cd ${SRC_ROOT}/${OPENSSH}/app/src/main/cpp/openssh
# autoreconf is normally in /usr/bin
autoreconf
./configure --host $TARGET --disable-lastlog --disable-utmp --disable-wtmp \
            --enable-largefile --without-openssl
cd ${SRC_ROOT}

# Add remote: "upstream-openssh" pointing to the location used above
git remote add upstream-openssh c:/tmp/sshd4a-tarballs/upstream-openssh
git fetch upstream-openssh
git merge --allow-unrelated-histories upstream-openssh/dev

#    All changes are (should be) marked with SSHD4A_*
#    Merge and solve conflicts as usual.
#    Update gradle.build: android.defaultConfig buildConfigField("String", "VERSION_OPENSSL"...
#    Commit and build...

# ############################################################################
# Step 2.3 - DROPBEAR - https://matt.ucc.asn.au/dropbear/dropbear.html
# https://matt.ucc.asn.au/dropbear/dropbear-2024.85.tar.bz2
# ############################################################################
# replace base filename in the below string after download:
export DROPBEAR_VERSION="dropbear-2024.85"

cd ${SRC_ROOT}
7z x -so ${DROPBEAR_VERSION}* | tar xf -
# rename the directory so we don't need to change the git remote names
export DROPBEAR="upstream-dropbear"

# Prep dropbear
mkdir -p ${DROPBEAR}/app/src/main/cpp/
mv ${DROPBEAR_VERSION} ${DROPBEAR}/app/src/main/cpp/dropbear
cd ${DROPBEAR}
echo -e "${GATRR}" >.gitattributes
git init .
# ignore warnings about txt files in "rsa-testvectors"
git add * .gitattributes
git commit -a -m "${DROPBEAR_VERSION}"
cd ${SRC_ROOT}

# Configure dropbear
cd ${SRC_ROOT}/${DROPBEAR}/app/src/main/cpp/dropbear
./configure --host $TARGET --disable-syslog --disable-lastlog \
            --disable-utmp --disable-wtmp \
            --enable-bundled-libtom --enable-largefile
cd ${SRC_ROOT}

# Add remote: "upstream-dropbear" pointing to the location used above
git remote add upstream-dropbear c:/tmp/sshd4a-tarballs/upstream-dropbear
git fetch upstream-dropbear

git merge --allow-unrelated-histories upstream-dropbear/dev

#    All changes are (should be) marked with SSHD4A_*
#    Merge and solve conflicts as usual.

cd ${SRC_ROOT}/${DROPBEAR}/app/src/main/cpp
./prebuild-dropbear.sh

#    Update gradle.build: android.defaultConfig buildConfigField("String", "VERSION_DROPBEAR"...
#    Commit and build...

# ############################################################################
config.h changes - should not be needed to reapply these after a code drop
as the config.h should be untouched.

------------------------------------------------------------------------------
# ${SRC_ROOT}/${RSYNC}/app/src/main/cpp/rsync/config.h
------------------------------------------------------------------------------
- armv7: extra "#define _FILE_OFFSET_BITS 64"
  which can be added to the 64 bit versions without any issue. Done.
- armv7 versus 64 using  #if defined(__aarch64__) || defined(__x86_64__ ) ...
  #define HAVE_LONG_DOUBLE 1        <==> absent
  #define HAVE_LONG_DOUBLE_WIDER 1  <==> absent
  #define SIZEOF_CHARP  8           <==> 4
  #define SIZEOF_LONG   8           <==> 4
  #define SIZEOF_TIME_T 8           <==> 4

------------------------------------------------------------------------------
# ${SRC_ROOT}/${RSYNC}/app/src/main/cpp/dropbear/config.h
------------------------------------------------------------------------------
- aarch64 and x86_64 were identical
- armv7: extra "#define _FILE_OFFSET_BITS 64"
  which can be added to the 64 bit versions without any issue. Done.

------------------------------------------------------------------------------
# ${SRC_ROOT}/${RSYNC}/app/src/main/cpp/openssh/config.h
------------------------------------------------------------------------------
- aarch64 and x86_64 were identical
- armv7: extra "#define _FILE_OFFSET_BITS 64"
  which can be added to the 64 bit versions without any issue. Done.
- armv7 versus 64 using  #if defined(__aarch64__) || defined(__x86_64__ ) ...
  #define SIZEOF_LONG_INT 8  <=>  4
  #define SIZEOF_TIME_T   8  <=>  4
- added manually:
  // configure presumes openbsd only, but android needs it.
  #define HAVE_ATTRIBUTE__SENTINEL__ 1
  // configure fails to find it due to android using an "#include_next"
  #define HAVE_MALLOC 1
  // see "openbsd-compat/explicit_bzero.c" workaround
  #define HAVE_BZERO 1

# ############################################################################

Setup signing:

    Edit your "~/.gradle/gradle.properties" and add a line:

        Sshd4a.properties=/path/to/Sshd4a.properties

    Edit/create the file "/path/to/Sshd4a.properties":

        sign.storeFile=/path/to/myKeystore.jks
        sign.storePassword=myPass
        sign.keyAlias=myAlias
        sign.keyPassword=myPass

# ############################################################################