base-files: sysupgrade: handle errors when generating backup

1. Return error if any step of generating tar file fails
2. Use pipefail to avoid calling "gzip" if tar failed

Fixes: e36cc530927c ("base-files: sysupgrade: use tar helper to include installed_packages.txt")
Reported-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Cc: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Cc: Jo-Philipp Wich <jo@mein.io>
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>

diff --git a/package/base-files/files/sbin/sysupgrade b/package/base-files/files/sbin/sysupgrade
index ed8871b8922f2d177f34073aaf3b1ad58a30d615..9b422107d8c7ab22f1ba099d8e97bf5fd3507983 100755 (executable)
--- a/package/base-files/files/sbin/sysupgrade
+++ b/package/base-files/files/sbin/sysupgrade
@@ -237,6 +237,7 @@ include /lib/upgrade
 create_backup_archive() {
        local conf_tar="$1"
        local disabled
+       local err
 
        [ "$(rootfs_type)" = "tmpfs" ] && {
                echo "Cannot save config while running from ramdisk." >&2
@@ -251,31 +252,43 @@ create_backup_archive() {
        v "Saving config files..."
        [ "$VERBOSE" -gt 1 ] && TAR_V="v" || TAR_V=""
        sed -i -e 's,^/,,' "$CONFFILES"
+       set -o pipefail
        {
-               for service in /etc/init.d/*; do
-                       if ! $service enabled; then
+               local ret=0
+
+               if [ $ret -eq 0 ]; then
+                       for service in /etc/init.d/*; do
+                               if ! $service enabled; then
                                disabled="$disabled$service disable\n"
-                       fi
-               done
-               disabled="$disabled\nexit 0"
-               tar_print_member "/etc/uci-defaults/10_disable_services" "$(echo -e $disabled)"
+                               fi
+                       done
+                       disabled="$disabled\nexit 0"
+                       tar_print_member "/etc/uci-defaults/10_disable_services" "$(echo -e $disabled)" || ret=1
+               fi
 
                # Part of archive with installed packages info
-               if [ "$SAVE_INSTALLED_PKGS" -eq 1 ]; then
-                       # Format: pkg-name<TAB>{rom,overlay,unknown}
-                       # rom is used for pkgs in /rom, even if updated later
-                       tar_print_member "$INSTALLED_PACKAGES" "$(find /usr/lib/opkg/info -name "*.control" \( \
-                               \( -exec test -f /rom/{} \; -exec echo {} rom \; \) -o \
-                               \( -exec test -f /overlay/upper/{} \; -exec echo {} overlay \; \) -o \
-                               \( -exec echo {} unknown \; \) \
-                               \) | sed -e 's,.*/,,;s/\.control /\t/')"
+               if [ $ret -eq 0 ]; then
+                       if [ "$SAVE_INSTALLED_PKGS" -eq 1 ]; then
+                               # Format: pkg-name<TAB>{rom,overlay,unknown}
+                               # rom is used for pkgs in /rom, even if updated later
+                               tar_print_member "$INSTALLED_PACKAGES" "$(find /usr/lib/opkg/info -name "*.control" \( \
+                                       \( -exec test -f /rom/{} \; -exec echo {} rom \; \) -o \
+                                       \( -exec test -f /overlay/upper/{} \; -exec echo {} overlay \; \) -o \
+                                       \( -exec echo {} unknown \; \) \
+                                       \) | sed -e 's,.*/,,;s/\.control /\t/')" || ret=1
+                       fi
                fi
 
                # Rest of archive with config files and ending padding
-               tar c${TAR_V} -C / -T "$CONFFILES"
+               if [ $ret -eq 0 ]; then
+                       tar c${TAR_V} -C / -T "$CONFFILES" || ret=1
+               fi
+
+               [ $ret -eq 0 ]
        } | gzip > "${conf_tar:-/proc/self/fd/1}"
+       err=$?
+       set +o pipefail
 
-       local err=$?
        if [ "$err" -ne 0 ]; then
                echo "Failed to create the configuration backup."
                [ -f "$conf_tar" ] && rm -f "$conf_tar"