tmpfiles.d: only 'w+' can have multiple lines for the same path

Since d0ea5c5e39dce60efbce6d86534eb9ca253440b0, all lines specifying actions
that recreate a file system object (such as 'f+, 'L+', etc ...) on the same
path were allowed. This had the bad side effect to break the tmpfiles
configuration file sorting for files defining such lines.

For example:

  # cat /etc/tmpfiles.d/a.conf
  f+ /tmp/file - - - - a.conf

  # cat /etc/tmpfiles.d/z.conf
  f+ /tmp/file - - - - z.conf

  # systemd-tmpfiles --create /etc/tmpfiles.d/{a,z}.conf
  # cat /tmp/file
  z.conf

Even though "a.conf" sorts lexicographically before "z.conf", the content of
/tmp/file was the result of the action defined in "z.conf"

This patch restores the old logic - if multiple files specify the same path,
the entry in the file with the lexicographically earliest name will be applied.

1 files changed, 24 insertions, 7 deletions

diff --git a/src/tmpfiles/tmpfiles.c b/src/tmpfiles/tmpfiles.c
index 023207bc60..f41f086be1 100644
--- a/src/tmpfiles/tmpfiles.c
+++ b/src/tmpfiles/tmpfiles.c
@@ -2896,6 +2896,26 @@ static int parse_age_by_from_arg(const char *age_by_str, Item *item) {
         return 0;
 }
 
+static bool is_duplicated_item(ItemArray *existing, Item *i) {
+
+        assert(existing);
+        assert(i);
+
+        for (size_t n = 0; n < existing->n_items; n++) {
+                Item *e = existing->items + n;
+
+                if (item_compatible(e, i))
+                        continue;
+
+                /* Only multiple 'w+' lines for the same path are allowed. */
+                if (e->type != WRITE_FILE || !e->append_or_force ||
+                    i->type != WRITE_FILE || !i->append_or_force)
+                        return true;
+        }
+
+        return false;
+}
+
 static int parse_line(
                 const char *fname,
                 unsigned line,
@@ -3247,13 +3267,10 @@ static int parse_line(
 
         existing = ordered_hashmap_get(h, i.path);
         if (existing) {
-                size_t n;
-
-                for (n = 0; n < existing->n_items; n++) {
-                        if (!item_compatible(existing->items + n, &i) && !i.append_or_force) {
-                                log_syntax(NULL, LOG_NOTICE, fname, line, 0, "Duplicate line for path \"%s\", ignoring.", i.path);
-                                return 0;
-                        }
+                if (is_duplicated_item(existing, &i)) {
+                        log_syntax(NULL, LOG_NOTICE, fname, line, 0,
+                                   "Duplicate line for path \"%s\", ignoring.", i.path);
+                        return 0;
                 }
         } else {
                 existing = new0(ItemArray, 1);