From a1910546a68052a1757eeffb62681cf567978f57 Mon Sep 17 00:00:00 2001
From: Kroese <kroese@users.noreply.github.com>
Date: Mon, 6 Jul 2026 07:44:41 +0200
Subject: [PATCH] feat: Check file operation results (#1212)

---
 src/disk.sh    | 47 ++++++++++++++++++++++-------------------------
 src/network.sh | 38 ++++++++++++++++++++++++++++----------
 2 files changed, 50 insertions(+), 35 deletions(-)

diff --git a/src/disk.sh b/src/disk.sh
index 2a0c6ff..7fefb74 100644
--- a/src/disk.sh
+++ b/src/disk.sh
@@ -38,15 +38,9 @@ fmt2ext() {
   local DISK_FMT="$1"
 
   case "${DISK_FMT,,}" in
-    qcow2)
-      echo "qcow2"
-      ;;
-    raw)
-      echo "img"
-      ;;
-    *)
-      error "Unrecognized disk format: $DISK_FMT" && exit 78
-      ;;
+    qcow2) echo "qcow2" ;;
+    raw) echo "img" ;;
+    *) error "Unrecognized disk format: $DISK_FMT" && exit 78 ;;
   esac
 }
 
@@ -54,15 +48,9 @@ ext2fmt() {
   local DISK_EXT="$1"
 
   case "${DISK_EXT,,}" in
-    qcow2)
-      echo "qcow2"
-      ;;
-    img)
-      echo "raw"
-      ;;
-    *)
-      error "Unrecognized file extension: .$DISK_EXT" && exit 78
-      ;;
+    qcow2) echo "qcow2" ;;
+    img) echo "raw" ;;
+    *) error "Unrecognized file extension: .$DISK_EXT" && exit 78 ;;
   esac
 }
 
@@ -118,7 +106,7 @@ allocateRaw() {
 
   fallocate -l "$DATA_SIZE" "$DISK_FILE" &>/dev/null && return 0
   fallocate -l -x "$DATA_SIZE" "$DISK_FILE" && return 0
-  truncate -s "$DATA_SIZE" "$DISK_FILE"
+  truncate -s "$DATA_SIZE" "$DISK_FILE" || return 1
 
   return 0
 }
@@ -260,7 +248,7 @@ resizeDisk() {
   local FS="$5"
   local CUR_SIZE DATA_SIZE DIR SPACE GB
 
-  CUR_SIZE=$(getSize "$DISK_FILE")
+  CUR_SIZE=$(getSize "$DISK_FILE") || exit 71
   DATA_SIZE=$(numfmt --from=iec "$DISK_SPACE")
   local REQ=$(( DATA_SIZE - CUR_SIZE ))
   (( REQ < 1 )) && error "Shrinking disks is not supported yet, please increase ${DISK_DESC^^}_SIZE." && exit 71
@@ -328,7 +316,7 @@ convertDisk() {
     local CUR_SIZE SPACE GB
 
     # Check free diskspace
-    CUR_SIZE=$(getSize "$SOURCE_FILE")
+    CUR_SIZE=$(getSize "$SOURCE_FILE") || exit 79
     SPACE=$(df --output=avail -B 1 "$DIR" | tail -n 1)
 
     if (( CUR_SIZE > SPACE )); then
@@ -371,8 +359,17 @@ convertDisk() {
     fi
   fi
 
-  rm -f "$SOURCE_FILE"
-  mv "$TMP_FILE" "$DST_FILE"
+  if ! rm -f "$SOURCE_FILE"; then
+    rm -f "$TMP_FILE"
+    error "Failed to remove old $DISK_DESC image $SOURCE_FILE."
+    exit 79
+  fi
+
+  if ! mv "$TMP_FILE" "$DST_FILE"; then
+    rm -f "$TMP_FILE"
+    error "Failed to move converted $DISK_DESC image to $DST_FILE."
+    exit 79
+  fi
 
   if isCow "$FS"; then
     FA=$(lsattr "$DST_FILE")
@@ -538,7 +535,7 @@ addDisk () {
 
   if [ -s "$DISK_FILE" ]; then
 
-    CUR_SIZE=$(getSize "$DISK_FILE")
+    CUR_SIZE=$(getSize "$DISK_FILE") || exit 71
 
     if (( DATA_SIZE > CUR_SIZE )); then
 
@@ -563,7 +560,7 @@ addDisk () {
 
   if [ -f "$DISK_FILE" ] && disabled "$ALLOCATE"; then
 
-    CUR_SIZE=$(getSize "$DISK_FILE")
+    CUR_SIZE=$(getSize "$DISK_FILE") || exit 73
     USED=$(du -sB 1 "$DISK_FILE" | cut -f1)
     FREE=$(df --output=avail -B 1 "$DIR" | tail -n 1)
     LEFT=$(( CUR_SIZE - USED - FREE ))
diff --git a/src/network.sh b/src/network.sh
index 1632fab..5906a14 100644
--- a/src/network.sh
+++ b/src/network.sh
@@ -136,7 +136,10 @@ configureDNS() {
   local gateway="$6"
   local arguments="$DNSMASQ_OPTS"
 
-  echo "$gateway" > /run/shm/qemu.gw
+  if ! echo "$gateway" > /run/shm/qemu.gw; then
+    error "Failed to write gateway file."
+    return 1
+  fi
 
   enabled "${DNSMASQ_DISABLE:-}" && return 0
   enabled "$DEBUG" && echo "Starting dnsmasq daemon..."
@@ -147,8 +150,8 @@ configureDNS() {
   if isNAT; then
 
     # Create lease file for faster resolve
-    echo "0 $mac $ip $host 01:$mac" > /var/lib/misc/dnsmasq.leases
-    chmod 644 /var/lib/misc/dnsmasq.leases
+    echo "0 $mac $ip $host 01:$mac" > /var/lib/misc/dnsmasq.leases || :
+    chmod 644 /var/lib/misc/dnsmasq.leases || :
 
     # dnsmasq configuration:
     arguments+=" --dhcp-authoritative"
@@ -405,14 +408,22 @@ configureSlirp() {
   [ -n "$forward" ] && NET_OPTS+=",$forward"
 
   if enabled "${DNSMASQ_DISABLE:-}"; then
-    echo "$gateway" > /run/shm/qemu.gw
+    echo "$gateway" > /run/shm/qemu.gw || warn "Failed to write gateway file."
   else
-    [ ! -f /etc/resolv.dnsmasq ] && cp /etc/resolv.conf /etc/resolv.dnsmasq
+    if [ ! -f /etc/resolv.dnsmasq ] && ! cp /etc/resolv.conf /etc/resolv.dnsmasq; then
+      error "Failed to backup /etc/resolv.conf."
+      return 1
+    fi
+
     configureDNS "lo" "$ip" "$VM_NET_MAC" "$VM_NET_HOST" "$VM_NET_MASK" "$gateway" || return 1
-    printf '%s\n' \
+
+    if ! printf '%s\n' \
       'nameserver 127.0.0.1' \
       'search .' \
-      'options ndots:0' > /etc/resolv.conf
+      'options ndots:0' > /etc/resolv.conf; then
+      error "Failed to update /etc/resolv.conf."
+      return 1
+    fi
   fi
 
   VM_NET_IP="$ip"
@@ -469,11 +480,18 @@ configurePasst() {
   PASST_OPTS+=" -q"
 
   if ! enabled "${DNSMASQ_DISABLE:-}"; then
-    [ ! -f /etc/resolv.dnsmasq ] && cp /etc/resolv.conf /etc/resolv.dnsmasq
-    printf '%s\n' \
+    if [ ! -f /etc/resolv.dnsmasq ] && ! cp /etc/resolv.conf /etc/resolv.dnsmasq; then
+      error "Failed to backup /etc/resolv.conf."
+      return 1
+    fi
+
+    if ! printf '%s\n' \
       'nameserver 127.0.0.1' \
       'search .' \
-      'options ndots:0' > /etc/resolv.conf
+      'options ndots:0' > /etc/resolv.conf; then
+      error "Failed to update /etc/resolv.conf."
+      return 1
+    fi
   fi
 
   PASST_OPTS=$(echo "$PASST_OPTS" | sed 's/\t/ /g' | tr -s ' ' | sed 's/^ *//')