Prefix subvolume paths with a / everywhere,

CHANGELOG.md

@@ -7,6 +7,12 @@ First official snazzer release.
 
 ### Added ###
 ### Changed ###
+- Snazzer doesn't treat all patterns in `/` like they were implicitly pre- and suffixed with `*`.
+  This behaviour now has to be specified explicitly.
+- Snazzer now explicitly makes subvolumes absolute by prefixing with `/`.
+  - All entries in `/etc/snazzer/exclude.patterns` need to be either absolute
+    (start with `/`) or start with a `*`.
+  - Paths displayed by snazzer are now absolute as well.
 ### Deprecated ###
 ### Removed ###
 ### Fixed ###

docs/examples/etc/snazzer/exclude.patterns

@@ -1,6 +1,6 @@
-var/cache
-var/lib/docker/*
-.snapshots
-tmp
+/var/cache
+/var/lib/docker/*
+*/.snapshots
+/tmp
 *backup*
 *secret*

docs/snazzer-measure.md

@@ -72,7 +72,7 @@ The output includes:
     Filename of newline separated list of shell glob patterns of subvolume pathnames
     which should be excluded from `snazzer --all` invocations; compatible with
     `--exclude-from` for **du** and **tar**.  Examples of subvolume patterns to
-    exclude from regular snapshotting: \*secret\*, /var/cache, /var/lib/docker/btrfs,
+    exclude from regular snapshotting: \*secret\*, /var/cache, /var/lib/docker/\*,
     .snapshots.  **NOTE:** `.snapshotz` is always excluded.
     Default:
 

docs/snazzer.md

@@ -76,10 +76,8 @@ snapshots already measured by current hostname
     Filename of newline separated list of shell glob patterns of subvolume pathnames
     which should be excluded from `snazzer --all` invocations; compatible with
     `--exclude-from` for **du** and **tar**.  Examples of subvolume patterns to
-    exclude from regular snapshotting: \*secret\*, var/cache, var/lib/docker/\*,
-    .snapshots. The patterns are matched against subvolumes as listed by
-    `btrfs subvolume list <path`>, without a leading /.
-    Note that   **NOTE:** `.snapshotz` is always excluded.
+    exclude from regular snapshotting: \*secret\*, /var/cache, /var/lib/docker/\*,
+    \*/.snapshots. Note that   **NOTE:** `.snapshotz` is always excluded.
     Default:
 
         SNAZZER_SUBVOLS_EXCLUDE_FILE="/etc/snazzer/exclude.patterns"
@@ -117,7 +115,7 @@ snapshots already measured by current hostname
     `mkdir`: atimes always return with the current local time, which is obvioulsy
     different from one second to the next. So we have no hope of creating
     reproducible shasums or PGP signatures unless those directories are excluded
-    from our measurements of the snapshot. See also: 
+    from our measurements of the snapshot. See also:
     [https://bugzilla.kernel.org/show\_bug.cgi?id=95201](https://bugzilla.kernel.org/show_bug.cgi?id=95201)
 
 # EXIT STATUS
@@ -137,6 +135,7 @@ already in progress, check lock dir at /var/run/snazzer-measure.lock
 - 9. tried to display man page with a formatter which is not installed
 - 10. missing `snazzer-measure` or `snazzer-prune-candidates` from PATH
 - 11. missing `btrfs` command from PATH
+- 12. syntax error in /etc/snazzer/exclude.patterns file.
 
 # SEE ALSO
 

snazzer

@@ -29,10 +29,10 @@ if ! $SUDO test -e "$SNAZZER_SUBVOLS_EXCLUDE_FILE"; then
     MISSING_SUBVOLS_EXCL_FILE="$SNAZZER_SUBVOLS_EXCLUDE_FILE"
     SNAZZER_SUBVOLS_EXCLUDE_FILE=$(mktemp)
     cat <<HERE > "$SNAZZER_SUBVOLS_EXCLUDE_FILE"
-var/cache
-var/lib/docker/*
-.snapshots
-tmp
+/var/cache
+/var/lib/docker/*
+*/.snapshots
+/tmp
 *backup*
 *secret*
 HERE
@@ -71,21 +71,30 @@ assert_btrfs_tools() {
     fi
 }
 
+# function duplicated in snazzer-measure
 glob2grep_file() {
     FILE=$1
     OUT=$(mktemp)
 
+    # check if every line starts with either / or *, if not, quit with a syntax error.
+    while read -r line; do
+        if ! echo "$line" | grep '^[/*]' >/dev/null; then
+            echo "SYNTAX ERROR: $1 contains line \"$line\" that starts with neither / nor *." >&2
+            exit 12
+        fi
+    done < "$1"
+
     # first, escape $, . and ^ with a backslash so they're taken literally
     # then, extend * to .* to emulate shell globbing.
     # finally, add ^ and $ to the line ends so the lines are not evaluated as *line*
     sed 's|[$.^]|\\&|g' "$FILE" | sed 's/\*/\.*/g' | sed 's/^/\^/g' | sed 's/$/\$/g' > "$OUT"
 
-
     echo "$OUT"
 }
 
 # This should only operate on a real mount(8) filesystem mountpoint, so call
 # assert_mountpoint before calling list_subvolumes.
+# the DIR argument is assumed to be without a trailing slash, i.e. "/" or "/mnt" but not "/mnt/"
 list_subvolumes() {
     DIR=$1
     DO_INVERT=$2
@@ -94,21 +103,30 @@ list_subvolumes() {
     else
         GREP="grep -v"
     fi
+
     if [ "$DIR" != "/" ]; then
-            DIR="$DIR/"
+        PREFIX="$DIR"
+    else
+        PREFIX=""
     fi
-    EXCL_FILE=$(glob2grep_file "$SNAZZER_SUBVOLS_EXCLUDE_FILE")
+
+    EXCL_FILE=$(glob2grep_file "$SNAZZER_SUBVOLS_EXCLUDE_FILE") || exit $?
     $SUDO btrfs subvolume list -t "$DIR" | tail -n+3 | \
-        sed 's/^[0-9]*[ \t]*[0-9]*[ \t]*[0-9]*[ \t]*//g' | \
+        # delete all columns except path, prefix the paths with a /
+        sed 's|^[0-9]*[ \t]*[0-9]*[ \t]*[0-9]*[ \t]*|/|g' | \
+        # add / line, as the root subvolume is not included in btrfs subvolume list
+        (echo "/"; cat) | \
         $GREP -f "$EXCL_FILE" | grep -v '\.snapshotz' | \
-        while read -r SUBVOL; do echo "${DIR}$SUBVOL"; done
+        while read -r SUBVOL; do echo "${PREFIX}$SUBVOL"; done
     rm "$EXCL_FILE"
 }
 
 report_subvols_excluded() {
     DIR=$1
     assert_mountpoint "$DIR"
-    NUM=$(list_subvolumes "$DIR" --excluded | wc -l)
+    SUBVOLS=$(list_subvolumes "$DIR" --excluded) || exit $?
+    # command substitution removes trailing newlines, we have to add it again for wc -l to give correct results.
+    NUM=$(printf "%s\n" "$SUBVOLS" | wc -l)
 
     if [ "$NUM" != "0" ]; then
         if [ "$DRY_RUN" = "1" ]; then printf "#"; fi
@@ -123,7 +141,7 @@ report_subvols_excluded() {
 # subvols later on.
 # SMELL: what if a subvol is mounted some place other than its path name?
 list_btrfs_mountpoints() {
-    EXCL_FILE=$(glob2grep_file "$SNAZZER_SUBVOLS_EXCLUDE_FILE")
+    EXCL_FILE=$(glob2grep_file "$SNAZZER_SUBVOLS_EXCLUDE_FILE") || exit $?
     df -t btrfs 2>/dev/null | tail -n+2 | awk '{ print $1 }' | sort | uniq | \
         while read -r DEV; do df --output=target "$DEV" | tail -n+2 ; done | \
         grep -v '\.snapshotz' | grep -v -f "$EXCL_FILE" || true
@@ -521,27 +539,23 @@ do_mountpoint() {
     if [ "$MOUNTPOINT" != "/" ]; then
         MOUNTPOINT=$(echo "$MOUNTPOINT" | sed 's|/$||g')
     fi
-    do_multiple "$DO_ACTION" "$MOUNTPOINT"
     report_subvols_excluded "$MOUNTPOINT" >> "$TMP_EXCL"
-    report_snapshot_dirs "$MOUNTPOINT" >> "$TMP_DIRS"
     assert_mountpoint "$MOUNTPOINT"
-    list_subvolumes "$MOUNTPOINT" | {
-        while read -r SUBVOL; do
-            do_multiple "$DO_ACTION" "$SUBVOL"
-            report_snapshot_dirs "$SUBVOL" >> "$TMP_DIRS"
-        done
-    }
+    SUBVOLS=$(list_subvolumes "$MOUNTPOINT") || exit $?
+    printf "%s\n" "$SUBVOLS" | while read -r SUBVOL; do
+        do_multiple "$DO_ACTION" "$SUBVOL"
+        report_snapshot_dirs "$SUBVOL" >> "$TMP_DIRS"
+    done
 }
 
 do_mountpoints() {
     TMP_EXCL=$(mktemp)
     TMP_DIRS=$(mktemp)
     if [ "$#" = 0 ]; then
-        list_btrfs_mountpoints | {
-            while read -r MOUNTPOINT; do
-                do_mountpoint "$MOUNTPOINT" "$TMP_EXCL" "$TMP_DIRS"
-            done
-        }
+        MOUNTPOINTS=$(list_btrfs_mountpoints) || exit $?
+        printf "%s\n" "$MOUNTPOINTS" | while read -r MOUNTPOINT; do
+            do_mountpoint "$MOUNTPOINT" "$TMP_EXCL" "$TMP_DIRS"
+        done
     else
         for MOUNTPOINT in "$@"; do
             do_mountpoint "$MOUNTPOINT" "$TMP_EXCL" "$TMP_DIRS"
@@ -682,10 +696,8 @@ snapshots already measured by current hostname
 Filename of newline separated list of shell glob patterns of subvolume pathnames
 which should be excluded from C<snazzer --all> invocations; compatible with
 C<--exclude-from> for B<du> and B<tar>.  Examples of subvolume patterns to
-exclude from regular snapshotting: *secret*, var/cache, var/lib/docker/*,
-.snapshots. The patterns are matched against subvolumes as listed by
-C<btrfs subvolume list <path>>, without a leading /.
-Note that   B<NOTE:> C<.snapshotz> is always excluded.
+exclude from regular snapshotting: *secret*, /var/cache, /var/lib/docker/*,
+*/.snapshots. Note that   B<NOTE:> C<.snapshotz> is always excluded.
 Default:
 
   SNAZZER_SUBVOLS_EXCLUDE_FILE="/etc/snazzer/exclude.patterns"
@@ -727,7 +739,7 @@ these empty directories behave differently to empty directories created with
 C<mkdir>: atimes always return with the current local time, which is obvioulsy
 different from one second to the next. So we have no hope of creating
 reproducible shasums or PGP signatures unless those directories are excluded
-from our measurements of the snapshot. See also: 
+from our measurements of the snapshot. See also:
 L<https://bugzilla.kernel.org/show_bug.cgi?id=95201>
 
 =back
@@ -761,6 +773,8 @@ already in progress, check lock dir at /var/run/snazzer-measure.lock
 
 =item 11. missing C<btrfs> command from PATH
 
+=item 12. syntax error in /etc/snazzer/exclude.patterns file.
+
 =back
 
 =head1 SEE ALSO

snazzer-measure

@@ -167,21 +167,35 @@ CMD
     echo ""
 }
 
+
+# function duplicated in snazzer
 glob2grep_file() {
     FILE=$1
     OUT=$(mktemp)
 
-    sed 's|[$.^]|\\&|g' "$FILE" | sed 's/\*/\.*/g' > "$OUT"
+    # check if every line starts with either / or *, if not, quit with a syntax error.
+    while read -r line; do
+        if ! echo "$line" | grep '^[/*]' >/dev/null; then
+            echo "SYNTAX ERROR: $1 contains line \"$line\" that starts with neither / nor *." >&2
+            exit 12
+        fi
+    done < "$1"
+
+    # first, escape $, . and ^ with a backslash so they're taken literally
+    # then, extend * to .* to emulate shell globbing.
+    # finally, add ^ and $ to the line ends so the lines are not evaluated as *line*
+    sed 's|[$.^]|\\&|g' "$FILE" | sed 's/\*/\.*/g' | sed 's/^/\^/g' | sed 's/$/\$/g' > "$OUT"
 
     echo "$OUT"
 }
 
+
 assert_gpg_secring_excluded() {
     if [ "$(gpg2 --list-secret-keys | wc -l)" = "0" ]; then
         echo "ERROR: no gpg2 --list-secret-keys" >&2
         exit 10
     fi
-    EXCL_FILE=$( glob2grep_file "$SNAZZER_SUBVOLS_EXCLUDE_FILE" )
+    EXCL_FILE=$(glob2grep_file "$SNAZZER_SUBVOLS_EXCLUDE_FILE") || exit $?
     N=$(gpg2 --list-secret-keys | grep '^/' | xargs readlink -f | \
         grep -v -f "$EXCL_FILE" | \
         (xargs --no-run-if-empty df -t btrfs 2>/dev/null) | wc -l)
@@ -385,7 +399,7 @@ time+offset C<YYYY-MM-DDTHHMMSS+hhmm>
 Filename of newline separated list of shell glob patterns of subvolume pathnames
 which should be excluded from C<snazzer --all> invocations; compatible with
 C<--exclude-from> for B<du> and B<tar>.  Examples of subvolume patterns to
-exclude from regular snapshotting: *secret*, /var/cache, /var/lib/docker/btrfs,
+exclude from regular snapshotting: *secret*, /var/cache, /var/lib/docker/*,
 .snapshots.  B<NOTE:> C<.snapshotz> is always excluded.
 Default:
 

tests/data/exclude.patterns

@@ -1,6 +1,6 @@
-var/cache
-var/lib/docker/*
-.snapshots
-tmp
+/var/cache
+/var/lib/docker/*
+*/.snapshots
+/tmp
 *backup*
 *secret*

tests/data/exclude.patterns.error

@@ -0,0 +1,7 @@
+/var/cache
+/var/lib/docker/*
+*/.snapshots
+/tmp
+foo
+*backup*
+*secret*

tests/snazzer.bats

@@ -47,6 +47,13 @@ expected_snapshots_raw() {
     [ "$status" = "0" ]
 }
 
+@test "snazzer --all check excludefile syntax" {
+    SNAZZER_SUBVOLS_EXCLUDE_FILE=$BATS_TEST_DIRNAME/data/exclude.patterns.error
+    run snazzer --all --dry-run "$MNT"
+    # 12 means that snazzer detected the errors in the file
+    [ "$status" = "12" ]
+}
+
 @test "snazzer --all [mountpoint]" {
     run snazzer --all "$MNT"
     expected_snapshots | sort > $(expected_file)