fix(build_library): Use sparse files for disk images, no useless sudo

Enable sparse files for all dd and cp commands and replace some dd
commands that are really better off being truncate commands.

While in the neighborhood there were a number of useless sudo commands
for things that just happen to be in sbin. Call them directly instead.

build_library/base_image_util.sh

@@ -100,11 +100,10 @@ create_base_image() {
 
   # Build root FS image.
   info "Building ${root_fs_img}"
-  dd if=/dev/zero of="${root_fs_img}" bs=1 count=1 \
-    seek=$((root_fs_bytes - 1)) status=none
-  sudo mkfs.ext2 -F -q -b ${fs_block_size} "${root_fs_img}" \
+  truncate --size="${root_fs_bytes}" "${root_fs_img}"
+  /sbin/mkfs.ext2 -F -q -b ${fs_block_size} "${root_fs_img}" \
     "$((root_fs_bytes / fs_block_size))"
-  sudo tune2fs -L "${root_fs_label}" \
+  /sbin/tune2fs -L "${root_fs_label}" \
                -U clear \
                -T 20091119110000 \
                -c 0 \
@@ -120,26 +119,23 @@ create_base_image() {
 
   # Build stateful FS disk image.
   info "Building ${stateful_fs_img}"
-  dd if=/dev/zero of="${stateful_fs_img}" bs=1 count=1 \
-    seek=$((stateful_fs_bytes - 1)) status=none
-  sudo mkfs.ext4 -F -q "${stateful_fs_img}"
-  sudo tune2fs -L "${stateful_fs_label}" -U "${stateful_fs_uuid}" \
+  truncate --size="${stateful_fs_bytes}" "${stateful_fs_img}"
+  /sbin/mkfs.ext4 -F -q "${stateful_fs_img}"
+  /sbin/tune2fs -L "${stateful_fs_label}" -U "${stateful_fs_uuid}" \
                -c 0 -i 0 "${stateful_fs_img}"
   mkdir -p "${stateful_fs_dir}"
   sudo mount -o loop "${stateful_fs_img}" "${stateful_fs_dir}"
 
   # Build ESP disk image.
   info "Building ${esp_fs_img}"
-  dd if=/dev/zero of="${esp_fs_img}" bs=1 count=1 \
-    seek=$((esp_fs_bytes - 1)) status=none
-  sudo mkfs.vfat "${esp_fs_img}"
+  truncate --size="${esp_fs_bytes}" "${esp_fs_img}"
+  /usr/sbin/mkfs.vfat "${esp_fs_img}"
 
   # Build OEM FS disk image.
   info "Building ${oem_fs_img}"
-  dd if=/dev/zero of="${oem_fs_img}" bs=1 count=1 \
-    seek=$((oem_fs_bytes - 1)) status=none
-  sudo mkfs.ext4 -F -q "${oem_fs_img}"
-  sudo tune2fs -L "${oem_fs_label}" -U "${oem_fs_uuid}" \
+  truncate --size="${oem_fs_bytes}" "${oem_fs_img}"
+  /sbin/mkfs.ext4 -F -q "${oem_fs_img}"
+  /sbin/tune2fs -L "${oem_fs_label}" -U "${oem_fs_uuid}" \
                -c 0 -i 0 "${oem_fs_img}"
   mkdir -p "${oem_fs_dir}"
   sudo mount -o loop "${oem_fs_img}" "${oem_fs_dir}"

build_library/build_common.sh

@@ -42,7 +42,7 @@ copy_image() {
   local dst="${BUILD_DIR}/$2"
   if should_build_image $1; then
     echo "Creating $2 from $1..."
-    cp "${src}" "${dst}" || die "Cannot copy $1 to $2"
+    cp --sparse=always "${src}" "${dst}" || die "Cannot copy $1 to $2"
   else
     mv "${src}" "${dst}" || die "Cannot move $1 to $2"
   fi

build_library/disk_layout_util.sh

@@ -168,7 +168,7 @@ EOF
     local file="part_${part}"
     local dir="dir_${part}"
     local target='"${TARGET}"'
-    local dd_args="bs=512 count=${size}"
+    local dd_args="bs=512 count=${size} conv=sparse"
     local start_b=$(( start * 512 ))
     local size_b=$(( size * 512 ))
     echo "dd if=${target} of=${file} ${dd_args} skip=${start}" >>"${unpack}"
@@ -226,19 +226,19 @@ build_gpt() {
 
   # Now populate the partitions.
   info "Copying stateful partition..."
-  $sudo dd if="$stateful_img" of="$outdev" conv=notrunc bs=512 \
+  $sudo dd if="$stateful_img" of="$outdev" conv=notrunc,sparse bs=512 \
       seek=$(partoffset ${outdev} ${stateful_fs_num}) status=none
 
   info "Copying rootfs..."
-  $sudo dd if="$rootfs_img" of="$outdev" conv=notrunc bs=512 \
+  $sudo dd if="$rootfs_img" of="$outdev" conv=notrunc,sparse bs=512 \
       seek=$(partoffset ${outdev} ${root_fs_num}) status=none
 
   info "Copying EFI system partition..."
-  $sudo dd if="$esp_img" of="$outdev" conv=notrunc bs=512 \
+  $sudo dd if="$esp_img" of="$outdev" conv=notrunc,sparse bs=512 \
       seek=$(partoffset ${outdev} ${esp_fs_num}) status=none
 
   info "Copying OEM partition..."
-  $sudo dd if="$oem_img" of="$outdev" conv=notrunc bs=512 \
+  $sudo dd if="$oem_img" of="$outdev" conv=notrunc,sparse bs=512 \
       seek=$(partoffset ${outdev} ${oem_fs_num}) status=none
 
   # Pre-set "sucessful" bit in gpt, so we will never mark-for-death
@@ -317,11 +317,11 @@ update_partition_table() {
              -t ${tguid} -u ${uguid} ${dst_img}
     if [ "${label}" != "STATE" ]; then
       # Copy source partition as-is.
-      dd if="${src_img}" of="${dst_img}" conv=notrunc bs=512 \
+      dd if="${src_img}" of="${dst_img}" conv=notrunc,sparse bs=512 \
         skip=${src_start} seek=${dst_start} count=${size} status=none
     else
       # Copy new stateful partition into place.
-      dd if="${src_state}" of="${dst_img}" conv=notrunc bs=512 \
+      dd if="${src_state}" of="${dst_img}" conv=notrunc,sparse bs=512 \
         seek=${dst_start} status=none
     fi
   done

build_library/vm_image_util.sh

@@ -164,7 +164,7 @@ unpack_source_disk() {
     TEMP_STATE="${VM_TMP_DIR}"/part_${NUM_STATEFUL}
     # Copy the replacement STATE image if it is set
     if [[ -n "${alternate_state_image}" ]]; then
-        cp "${alternate_state_image}" "${TEMP_STATE}"
+        cp --sparse=always "${alternate_state_image}" "${TEMP_STATE}"
     fi
 
     TEMP_PMBR="${VM_TMP_DIR}"/pmbr
@@ -216,14 +216,14 @@ install_oem_package() {
 # Write the vm disk image to the target directory in the proper format
 write_vm_disk() {
     info "Writing partitions to new disk image"
-    dd if="${TEMP_ROOTFS}" of="${VM_TMP_IMG}" conv=notrunc bs=512 \
-      seek=$(partoffset ${VM_TMP_IMG} ${NUM_ROOTFS_A})
-    dd if="${TEMP_STATE}"  of="${VM_TMP_IMG}" conv=notrunc bs=512 \
-      seek=$(partoffset ${VM_TMP_IMG} ${NUM_STATEFUL})
-    dd if="${TEMP_ESP}"    of="${VM_TMP_IMG}" conv=notrunc bs=512 \
-      seek=$(partoffset ${VM_TMP_IMG} ${NUM_ESP})
-    dd if="${TEMP_OEM}"    of="${VM_TMP_IMG}" conv=notrunc bs=512 \
-      seek=$(partoffset ${VM_TMP_IMG} ${NUM_OEM})
+    dd if="${TEMP_ROOTFS}" of="${VM_TMP_IMG}" conv=notrunc,sparse \
+        bs=512 seek=$(partoffset ${VM_TMP_IMG} ${NUM_ROOTFS_A})
+    dd if="${TEMP_STATE}"  of="${VM_TMP_IMG}" conv=notrunc,sparse \
+        bs=512 seek=$(partoffset ${VM_TMP_IMG} ${NUM_STATEFUL})
+    dd if="${TEMP_ESP}"    of="${VM_TMP_IMG}" conv=notrunc,sparse \
+        bs=512 seek=$(partoffset ${VM_TMP_IMG} ${NUM_ESP})
+    dd if="${TEMP_OEM}"    of="${VM_TMP_IMG}" conv=notrunc,sparse \
+        bs=512 seek=$(partoffset ${VM_TMP_IMG} ${NUM_OEM})
 
     if [[ $(_get_vm_opt HYBRID_MBR) -eq 1 ]]; then
         info "Creating hybrid MBR"