zfsbootmenu-core: discard stderr on zfs/zpool cmds

Most interactions with zfs/zpool binaries shouldn't allow stderr to
print to the controlling terminal, so just discard it. The few times
it's useful, send it to stdout instead where it's captured by the
subshell.

Co-authored-by: Min Idzelis <[email protected]>
Co-authored-by: Zach Dykstra <[email protected]>
Closes: #583

Author: zdykstra

zfsbootmenu/lib/zfsbootmenu-core.sh

@@ -160,7 +160,7 @@ match_hostid() {
           fi
           ;;
       esac
-    done <<<"$( zpool import )"
+    done <<<"$( zpool import 2>/dev/null )"
   fi
 
   zdebug "importable pools: ${importable[*]}"
@@ -227,7 +227,7 @@ log_unimportable() {
       *)
         ;;
     esac
-  done <<<"$( zpool import )"
+  done <<<"$( zpool import 2>/dev/null )"
 }
 
 # args: none
@@ -239,7 +239,7 @@ check_for_pools() {
 
   while read -r pool ; do
     [ -n "${pool}" ] && return 0
-  done <<<"$( zpool list -H -o name )"
+  done <<<"$( zpool list -H -o name 2>/dev/null )"
 
   return 1
 }
@@ -612,7 +612,7 @@ create_snapshot() {
   load_key "${selected}"
 
   zdebug "creating snapshot ${selected}@${target}"
-  if ! output="$( zfs snapshot "${selected}@${target}" )" ; then
+  if ! output="$( zfs snapshot "${selected}@${target}" 2>&1 )" ; then
     zdebug "unable to create snapshot: ${output}"
     return 1
   fi
@@ -677,7 +677,7 @@ rollback_snapshot() {
   CLEAR_SCREEN=1 load_key "${snap}"
 
   zdebug "will roll back ${snap}"
-  if ! output="$( zfs rollback -r "${snap}" )"; then
+  if ! output="$( zfs rollback -r "${snap}" 2>&1 )"; then
     zerror "failed to roll back snapshot ${snap}"
     zerror "${output}"
     return 1
@@ -843,7 +843,7 @@ find_be_kernels() {
   zdebug "fs set to ${fs}"
 
   # Try to mount, just skip the list otherwise
-  if ! mnt="$( mount_zfs "${fs}" )"; then
+  if ! mnt="$( mount_zfs "${fs}" 2>&1 )"; then
     zerror "unable to mount ${fs}"
     return 1
   fi
@@ -910,7 +910,7 @@ select_kernel() {
   kexec_args="$( tail -1 "${kernel_list}" )"
 
   # If a specific kernel is listed, prefer it when possible
-  specific_kernel="$( zfs get -H -o value org.zfsbootmenu:kernel "${zfsbe}" )"
+  specific_kernel="$( zfs get -H -o value org.zfsbootmenu:kernel "${zfsbe}" 2>/dev/null )"
   if [ "${specific_kernel}" != "-" ]; then
     zdebug "org.zfsbootmenu:kernel set to ${specific_kernel}"
     while read -r spec_kexec_args; do
@@ -954,7 +954,7 @@ find_root_prefix() {
   zdebug "zfsbe_mnt set to ${zfsbe_mnt}"
 
   # Grab the root prefix from a property if possible
-  if prefix="$( zfs get -H -o value org.zfsbootmenu:rootprefix "${zfsbe_fs}" )"; then
+  if prefix="$( zfs get -H -o value org.zfsbootmenu:rootprefix "${zfsbe_fs}" 2>/dev/null )"; then
     if [ "${prefix}" != "-" ]; then
       zdebug "using org.zfsbootmenu:rootprefix: ${prefix}"
       echo "${prefix}"
@@ -1211,7 +1211,7 @@ rewind_checkpoint() {
         checkpoint="${line#checkpoint: }"
         ;;
     esac
-  done <<<"$( zpool status "${pool}" )"
+  done <<<"$( zpool status "${pool}" 2>/dev/null )"
 
   [ -z "${checkpoint}" ] && return 1
   tput clear
@@ -1557,7 +1557,7 @@ be_has_encroot() {
 
   pool="${fs%%/*}"
 
-  if [ "$( zpool list -H -o feature@encryption "${pool}" )" != "active" ]; then
+  if [ "$( zpool list -H -o feature@encryption "${pool}" 2>/dev/null )" != "active" ]; then
     zdebug "feature@encryption not active on ${pool}"
     echo ""
     return 1
@@ -1591,7 +1591,7 @@ be_is_locked() {
 
   if encroot="$( be_has_encroot "${fs}" )"; then
     zdebug "${encroot} discovered as encryption root for ${fs}"
-    keystatus="$( zfs get -H -o value keystatus "${encroot}" )"
+    keystatus="$( zfs get -H -o value keystatus "${encroot}" 2>&1 )"
     zdebug "${encroot} keystatus: ${keystatus}"
     case "${keystatus}" in
       unavailable)
@@ -1621,7 +1621,7 @@ be_keysource() {
   fi
   zdebug "fs set to ${fs}"
 
-  if ! keysrc="$( zfs get -H -o value org.zfsbootmenu:keysource "${fs}" )"; then
+  if ! keysrc="$( zfs get -H -o value org.zfsbootmenu:keysource "${fs}" 2>/dev/null )"; then
     zwarn "failed to read org.zfsbootmenu:keysource on ${fs}"
     echo ""
     return 1
@@ -1720,7 +1720,7 @@ cache_key() {
   fi
 
   relkeyloc=""
-  if ksmount="$(zfs get -o value -H mountpoint "${keysrc}" )"; then
+  if ksmount="$(zfs get -o value -H mountpoint "${keysrc}" 2>/dev/null )"; then
     case "${ksmount}" in
       none|legacy)
         zdebug "no discernable mountpoint for ${keysrc}, using only absolute key path"
@@ -1817,7 +1817,7 @@ load_key() {
   [ -n "${NO_CACHE}" ] || NO_CACHE=0
 
   # If something goes wrong discovering key location, just prompt
-  if ! keylocation="$( zfs get -H -o value keylocation "${encroot}" )"; then
+  if ! keylocation="$( zfs get -H -o value keylocation "${encroot}" 2>/dev/null )"; then
     zdebug "failed to read keylocation on ${encroot}"
     keylocation="prompt"
   fi
@@ -1866,7 +1866,7 @@ load_key() {
   fi
 
   # Otherwise, try to prompt for "passphrase" keys
-  keyformat="$( zfs get -H -o value keyformat "${encroot}" )" || keyformat=""
+  keyformat="$( zfs get -H -o value keyformat "${encroot}" 2>/dev/null )" || keyformat=""
   if [ "${keyformat}" != "passphrase" ]; then
     zdebug "unable to load key with format ${keyformat} for ${encroot}"
     return 1