Use "getent group" instead of reading "/etc/group" to get group information (#14316)

* Use getent group instead of /etc/group to search groups

* Fallback to 'cat /etc/groups' if no getent exists

* Use group_exists() in netdata-installer.sh

* Rename group_exists() to get_group()

netdata-installer.sh

@@ -1200,8 +1200,8 @@ run chmod 770 "${NETDATA_CLAIMING_DIR}"
 if [ "$(id -u)" -eq 0 ]; then
   # find the admin group
   admin_group=
-  test -z "${admin_group}" && getent group root > /dev/null 2>&1 && admin_group="root"
-  test -z "${admin_group}" && getent group daemon > /dev/null 2>&1 && admin_group="daemon"
+  test -z "${admin_group}" && get_group root > /dev/null 2>&1 && admin_group="root"
+  test -z "${admin_group}" && get_group daemon > /dev/null 2>&1 && admin_group="daemon"
   test -z "${admin_group}" && admin_group="${NETDATA_GROUP}"
 
   run chown "${NETDATA_USER}:${admin_group}" "${NETDATA_LOG_DIR}"

packaging/installer/functions.sh

@@ -396,6 +396,14 @@ get_os_key() {
   fi
 }
 
+get_group(){
+  if command -v getent > /dev/null 2>&1; then
+    getent group "${1:-""}"
+  else
+    cat /etc/group | grep "^${1}:" 
+  fi
+}
+
 issystemd() {
   pids=''
   p=''
@@ -933,7 +941,7 @@ portable_add_group() {
   groupname="${1}"
 
   # Check if group exist
-  if cut -d ':' -f 1 < /etc/group | grep "^${groupname}$" 1> /dev/null 2>&1; then
+  if get_group "${groupname}" > /dev/null 2>&1; then
     echo >&2 "Group '${groupname}' already exists."
     return 0
   fi
@@ -969,14 +977,14 @@ portable_add_user_to_group() {
   username="${2}"
 
   # Check if group exist
-  if ! cut -d ':' -f 1 < /etc/group | grep "^${groupname}$" > /dev/null 2>&1; then
+  if ! get_group "${groupname}" > /dev/null 2>&1; then
     echo >&2 "Group '${groupname}' does not exist."
     # Don’t treat this as a failure, if the group does not exist we should not be trying to add the user to it.
     return 0
   fi
 
   # Check if user is in group
-  if expr ",$(grep "^${groupname}:" < /etc/group | cut -d ':' -f 4)," : ",""${username}"","; then
+  if get_group "${groupname}" | cut -d ':' -f 4 | grep -wq "${username}"; then
     # username is already there
     echo >&2 "User '${username}' is already in group '${groupname}'."
     return 0

packaging/installer/netdata-uninstaller.sh

@@ -426,7 +426,7 @@ portable_del_group() {
 
   # Linux
   if command -v groupdel 1> /dev/null 2>&1; then
-    if grep -q "${groupname}" /etc/group; then
+    if get_group "${groupname}" > /dev/null 2>&1; then
       run groupdel "${groupname}" && return 0
     else
       info "Group ${groupname} already removed in a previous step."