e2scrub: fix pathname escaping across all service definitions

systemd services provide an "instance name" that can be associated with
a particular invocation of a service.  This allows service users to
invoke multiple copies of a service, each with a unique string.  For
e2scrub, we pass the mountpoint of the filesystem as the instance name.
However, systemd services aren't supposed to have slashes in them, so
we're supposed to escape them.

The canonical escaping scheme for pathnames is defined by the
systemd-escape --path command.  Unfortunately, we've been adding our own
opinionated sauce for years, to work around the fact that --path didn't
quite work right in systemd before January 2017.  The special sauce is
incorrect, and we no longer care about systemd of 7 years past.

Clean up this mess by following the systemd escaping scheme throughout
the service units.  Now we can use the '%f' specifier in them, which
makes things a lot less complicated.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>

diff --git a/scrub/e2scrub@.service.in b/scrub/e2scrub@.service.in
index 496f894..6425263 100644 (file)
--- a/scrub/e2scrub@.service.in
+++ b/scrub/e2scrub@.service.in
@@ -1,5 +1,5 @@
 [Unit]
-Description=Online ext4 Metadata Check for %I
+Description=Online ext4 Metadata Check for %f
 OnFailure=e2scrub_fail@%i.service
 Documentation=man:e2scrub(8)
 
@@ -16,5 +16,5 @@ User=root
 IOSchedulingClass=idle
 CPUSchedulingPolicy=idle
 Environment=SERVICE_MODE=1
-ExecStart=@root_sbindir@/e2scrub -t %I
+ExecStart=@root_sbindir@/e2scrub -t %f
 SyslogIdentifier=%N

diff --git a/scrub/e2scrub_all.in b/scrub/e2scrub_all.in
index 4288b96..437f6cc 100644 (file)
--- a/scrub/e2scrub_all.in
+++ b/scrub/e2scrub_all.in
@@ -146,22 +146,10 @@ ls_targets() {
        fi
 }
 
-# systemd doesn't know to do path escaping on the instance variable we pass
-# to the e2scrub service, which breaks things if there is a dash in the path
-# name.  Therefore, do the path escaping ourselves if needed.
-#
-# systemd path escaping also drops the initial slash so we add that back in so
-# that log messages from the service units preserve the full path and users can
-# look up log messages using full paths.  However, for "/" the escaping rules
-# do /not/ drop the initial slash, so we have to special-case that here.
+# Turn our mount path into a service name that systemd will recognize
 escape_path_for_systemd() {
        local path="$1"
-
-       if [ "${path}" != "/" ]; then
-               echo "-$(systemd-escape --path "${path}")"
-       else
-               echo "-"
-       fi
+       systemd-escape --template 'e2scrub@.service' --path "${path}"
 }
 
 # Scrub any mounted fs on lvm by creating a snapshot and fscking that.
@@ -170,8 +158,8 @@ for tgt in "${targets[@]}"; do
        # If we're not reaping and systemd is present, try invoking the
        # systemd service.
        if [ "${reap}" -ne 1 ] && type systemctl > /dev/null 2>&1; then
-               tgt_esc="$(escape_path_for_systemd "${tgt}")"
-               ${DBG} systemctl start "e2scrub@${tgt_esc}" 2> /dev/null
+               svcname="$(escape_path_for_systemd "${tgt}")"
+               ${DBG} systemctl start "${svcname}" 2> /dev/null
                res=$?
                if [ "${res}" -eq 0 ] || [ "${res}" -eq 1 ]; then
                        continue;

diff --git a/scrub/e2scrub_fail.in b/scrub/e2scrub_fail.in
index 2c0754a..6899c47 100644 (file)
--- a/scrub/e2scrub_fail.in
+++ b/scrub/e2scrub_fail.in
@@ -2,8 +2,8 @@
 
 # Email logs of failed e2scrub unit runs when the systemd service fails.
 
-device="$1"
-test -z "${device}" && exit 0
+mntpoint="$1"
+test -z "${mntpoint}" && exit 0
 
 if ! type sendmail > /dev/null 2>&1; then
        echo "$0: sendmail program not found."
@@ -16,7 +16,7 @@ fi
 
 hostname="$(hostname -f 2>/dev/null)"
 test -z "${hostname}" && hostname="${HOSTNAME}"
-service_name="e2scrub@$(systemd-escape ${device})"
+service_name="$(systemd-escape --template "e2scrub@.service" --path "${mntpoint}")"
 
 if test -z "${recipient}" ; then
     recipient="root"
@@ -29,9 +29,9 @@ fi
 (cat << ENDL
 To: ${recipient}
 From: ${sender}
-Subject: e2scrub failure on ${device}
+Subject: e2scrub failure on ${mntpoint}
 
-So sorry, the automatic e2scrub of ${device} on ${hostname} failed.
+So sorry, the automatic e2scrub of ${mntpoint} on ${hostname} failed.
 
 A log of what happened follows:
 ENDL

diff --git a/scrub/e2scrub_fail@.service.in b/scrub/e2scrub_fail@.service.in
index 4bad311..ae65a1d 100644 (file)
--- a/scrub/e2scrub_fail@.service.in
+++ b/scrub/e2scrub_fail@.service.in
@@ -1,10 +1,10 @@
 [Unit]
-Description=Online ext4 Metadata Check Failure Reporting for %I
+Description=Online ext4 Metadata Check Failure Reporting for %f
 Documentation=man:e2scrub(8)
 
 [Service]
 Type=oneshot
-ExecStart=@pkglibdir@/e2scrub_fail "%I"
+ExecStart=@pkglibdir@/e2scrub_fail "%f"
 User=mail
 Group=mail
 SupplementaryGroups=systemd-journal