From 36212d3cbff777fd3fc1bbe855df531dc2692697 Mon Sep 17 00:00:00 2001
From: builder <builder@junest.org>
Date: Fri, 25 Dec 2015 15:26:54 +0000
Subject: [PATCH] Issue #127: Do not let proot mount the mtab file

This change prevents inconsistency problems when the JuNest environment
is run simultaneously in fakeroot and normal user. The mtab file is
never mount by proot but, instead, it is symlinked to /proc/self/mounts.
---
 lib/core.sh        | 21 +++++++++++++++++++--
 tests/test_core.sh |  2 +-
 2 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/lib/core.sh b/lib/core.sh
index b85c1fa..250917d 100644
--- a/lib/core.sh
+++ b/lib/core.sh
@@ -229,6 +229,8 @@ function run_env_as_root(){
     trap - QUIT EXIT ABRT KILL TERM INT
     trap "[ -z $uid ] || chown_cmd -R ${uid} ${JUNEST_HOME}; rm_cmd -f ${JUNEST_HOME}/etc/mtab" EXIT QUIT ABRT KILL TERM INT
 
+    # The mtab file should already be available in the image.
+    # This following instruction will be deleted
     [ ! -e ${JUNEST_HOME}/etc/mtab ] && ln_cmd -s /proc/self/mounts ${JUNEST_HOME}/etc/mtab
 
     JUNEST_ENV=1 chroot_cmd "$JUNEST_HOME" "${SH[@]}" "-c" "${main_cmd}"
@@ -269,6 +271,8 @@ function _run_env_with_qemu(){
 function run_env_as_fakeroot(){
     (( EUID == 0 )) && \
         die "You cannot access with root privileges. Use --root option instead."
+    # The mtab file should already be available in the image.
+    # This following instruction will be deleted
     [ ! -e ${JUNEST_HOME}/etc/mtab ] && ln_cmd -s /proc/self/mounts ${JUNEST_HOME}/etc/mtab
     _run_env_with_qemu "-S ${JUNEST_HOME} $1" "${@:2}"
 }
@@ -276,10 +280,23 @@ function run_env_as_fakeroot(){
 function run_env_as_user(){
     (( EUID == 0 )) && \
         die "You cannot access with root privileges. Use --root option instead."
-    [ -e ${JUNEST_HOME}/etc/mtab ] && rm_cmd -f ${JUNEST_HOME}/etc/mtab
-    _run_env_with_qemu "-R ${JUNEST_HOME} $1" "${@:2}"
+    # The mtab file should already be available in the image.
+    # This following instruction will be deleted
+    [ ! -e ${JUNEST_HOME}/etc/mtab ] && ln_cmd -s /proc/self/mounts ${JUNEST_HOME}/etc/mtab
+    _run_env_with_qemu "$(_provide_bindings_as_user) -r ${JUNEST_HOME} $1" "${@:2}"
 }
 
+function _provide_bindings_as_user(){
+    # The list of bindings can be found in `proot --help`. This function excludes
+    # /etc/mtab file so that it will not give conflicts with the related
+    # symlink in the image.
+    local existing_bindings=""
+    for bind in "/etc/host.conf" "/etc/hosts" "/etc/hosts.equiv" "/etc/netgroup" "/etc/networks" "/etc/passwd" "/etc/group" "/etc/nsswitch.conf" "/etc/resolv.conf" "/etc/localtime" "/dev" "/sys" "/proc" "/tmp" "$HOME"
+    do
+        [ -e "$bind" ] && existing_bindings="-b $bind $existing_bindings"
+    done
+    echo $existing_bindings
+}
 
 function delete_env(){
     ! ask "Are you sure to delete ${NAME} located in ${JUNEST_HOME}" "N" && return
diff --git a/tests/test_core.sh b/tests/test_core.sh
index bc23b88..d73a613 100755
--- a/tests/test_core.sh
+++ b/tests/test_core.sh
@@ -263,7 +263,7 @@ function test_run_env_as_proot_mtab(){
     $(run_env_as_fakeroot "-k 3.10" "echo")
     assertTrue "[ -e $JUNEST_HOME/etc/mtab ]"
     $(run_env_as_user "-k 3.10" "echo")
-    assertTrue "[ ! -e $JUNEST_HOME/etc/mtab ]"
+    assertTrue "[ -e $JUNEST_HOME/etc/mtab ]"
 }
 
 function test_run_env_as_root_mtab(){