Merge pull request #72 from fsquillace/issue_71_chroot

Issue #71: Use chroot to fallback in root mode

.travis.yml

@@ -1,5 +1,7 @@
 language: bash
 
+sudo: required
+
 install:
     - PATH=$PWD/bin:$PATH
     - juju -f echo 'Installing juju'
@@ -8,13 +10,14 @@ install:
     - juju -f pacman --noconfirm -S base-devel
 
 script:
-    - SKIP_ROOT_TESTS=1 ./tests/test_all.sh
+    - ./tests/test_all.sh
 # Test on installing package from AUR
     - juju -f yaourt --noconfirm -S tcptraceroute
+    - sudo $PWD/bin/juju -r tcptraceroute localhost
 # Test on installing package from official repo
-    - juju -f pacman --noconfirm -S sysstat
-    - juju -f iostat
-# Test on installing package from official repo with root access (TODO: may not work in ubuntu)
-    #- juju -f pacman --noconfirm -S iftop
-    #- sudo bin/juju -r iftop -t -s 5
+    - juju -f pacman --noconfirm -S tree
+    - juju -f tree
+# Test on installing package from official repo with root access
+    - juju -f pacman --noconfirm -S iftop
+    - sudo bin/juju -r iftop -t -s 5
     - yes | juju -d

README.md

@@ -96,6 +96,10 @@ Check out the proot options with:
 
     juju -p "--help"
 
+###Automatic fallback to classic chroot###
+Since the [arch-chroot](https://wiki.archlinux.org/index.php/Chroot) may not work
+on some distros, JuJu automatically tries to fallback to the classic chroot.
+
 ### JuJu as a container ###
 Although JuJu has not been designed to be a complete container, it is even possible to
 virtualize the process tree thanks to the [systemd container](https://wiki.archlinux.org/index.php/Systemd-nspawn).

lib/core.sh

@@ -75,9 +75,10 @@ PROOT_LINK=http://static.proot.me/proot-${ARCH}
 
 SH=("/bin/sh" "--login")
 CHROOT=${JUJU_HOME}/usr/bin/arch-chroot
+CLASSIC_CHROOT=${JUJU_HOME}/usr/bin/chroot
 TRUE=/usr/bin/true
 ID="/usr/bin/id -u"
-CHOWN="/usr/bin/chown"
+CHOWN="${JUJU_HOME}/usr/bin/chown"
 
 ################################# MAIN FUNCTIONS ##############################
 
@@ -164,8 +165,18 @@ function run_juju_as_root(){
     trap - QUIT EXIT ABRT KILL TERM INT
     trap "[ -z $uid ] || ${CHOWN} -R ${uid} ${JUJU_HOME}" EXIT QUIT ABRT KILL TERM INT
 
-    JUJU_ENV=1 ${CHROOT} $JUJU_HOME "${SH[@]}" "-c" "${cmd}"
-    local ret=$?
+    if ${CHROOT} $JUJU_HOME ${TRUE} &> /dev/null
+    then
+        JUJU_ENV=1 ${CHROOT} $JUJU_HOME "${SH[@]}" "-c" "${cmd}"
+        local ret=$?
+    elif ${CLASSIC_CHROOT} $JUJU_HOME ${TRUE} &> /dev/null
+    then
+        warn "Warning: The executable arch-chroot does not work, falling back to classic chroot"
+        JUJU_ENV=1 ${CLASSIC_CHROOT} $JUJU_HOME "${SH[@]}" "-c" "${cmd}"
+        local ret=$?
+    else
+        die "Error: Chroot does not work"
+    fi
 
     # The ownership of the files in JuJu is assigned to the real user
     [ -z $uid ] || ${CHOWN} -R ${uid} ${JUJU_HOME}
@@ -270,7 +281,8 @@ function build_image_juju(){
     info "Installing pacman and its dependencies..."
     # The archlinux-keyring and libunistring are due to missing dependencies declaration in ARM archlinux
     # yaourt requires sed
-    sudo pacstrap -G -M -d ${maindir}/root pacman arch-install-scripts binutils libunistring nano archlinux-keyring sed
+    # coreutils is needed for chown
+    sudo pacstrap -G -M -d ${maindir}/root pacman arch-install-scripts coreutils binutils libunistring nano archlinux-keyring sed
     sudo bash -c "echo 'Server = $DEFAULT_MIRROR' >> ${maindir}/root/etc/pacman.d/mirrorlist"
 
     info "Generating the locales..."

tests/test_core.sh

@@ -104,29 +104,46 @@ function test_run_juju_as_root(){
 
     install_mini_juju
     CHROOT="sudo $CHROOT"
+    CLASSIC_CHROOT="sudo $CLASSIC_CHROOT"
     CHOWN="sudo $CHOWN"
 
     local output=$(run_juju_as_root pwd)
-    assertEquals "$output" "/"
+    assertEquals "/" "$output"
     run_juju_as_root [ -e /run/lock ]
-    assertEquals $? 0
+    assertEquals 0 $?
     run_juju_as_root [ -e $HOME ]
-    assertEquals $? 0
+    assertEquals 0 $?
 
     # test that normal user has ownership of the files created by root
     run_juju_as_root touch /a_root_file
     local output=$(run_juju_as_root stat -c '%u' /a_root_file)
-    assertEquals "$output" "$UID"
+    assertEquals "$UID" "$output"
 
     SH=("sh" "--login" "-c" "type -t type")
     local output=$(run_juju_as_root)
-    assertEquals "$output" "builtin"
+    assertEquals "builtin" "$output"
     SH=("sh" "--login" "-c" "[ -e /run/lock ]")
     run_juju_as_root
-    assertEquals $? 0
+    assertEquals 0 $?
     SH=("sh" "--login" "-c" "[ -e $HOME ]")
     run_juju_as_root
-    assertEquals $? 0
+    assertEquals 0 $?
+}
+
+function test_run_juju_as_classic_root(){
+    [ $SKIP_ROOT_TESTS -eq 1 ] && return
+
+    install_mini_juju
+    CHROOT="sudo unknowncommand"
+    CLASSIC_CHROOT="sudo $CLASSIC_CHROOT"
+    CHOWN="sudo $CHOWN"
+
+    local output=$(run_juju_as_root pwd 2> /dev/null)
+    assertEquals "/" "$output"
+    run_juju_as_root [ -e /run/lock ] 2> /dev/null
+    assertEquals 0 $?
+    run_juju_as_root [ -e $HOME ] 2> /dev/null
+    assertEquals 0 $?
 }
 
 function test_run_juju_as_user(){