sd-journal: do not reset sd_j_enumerate_unique position on error

systemctl would call sd_j_enumerate_unique() interleaved with
sd_j_next(). But the latter can remove a file if it detects an
error in it. In those circumstances sd_j_enumerate_unique would
restart with the first file in hashmap. With many corrupted files
sd_j_enumerate_unique might iterate over the list multiple times.

Avoid this by jumping to the next file in unique list if possible,
or setting a flag that tells sd_j_enumerate_unique that it is done
otherwise.

1 files changed, 4 insertions, 0 deletions

diff --git a/src/journal/journal-internal.h b/src/journal/journal-internal.h
index 2f1f7fc771..e591fb61f8 100644
--- a/src/journal/journal-internal.h
+++ b/src/journal/journal-internal.h
@@ -124,6 +124,10 @@ struct sd_journal {
 
         bool on_network;
         bool no_new_files;
+        bool unique_file_lost; /* File we were iterating over got
+                                  removed, and there were no more
+                                  files, so sd_j_enumerate_unique
+                                  will return a value equal to 0. */
 
         size_t data_threshold;