journal: crash when filesystem is low on space

When space is getting too low on a file system rotating the journal file
will fail after the rotation, as opening the new logfile will fail.

Recognize this when logging the error and don't try to dereference a
NULL JournalFile pointer.

diff --git a/src/journal/journald.c b/src/journal/journald.c
index 87390bdec9921538e3f4c2f6943fffab79e25703..7d798d96822dcf5bd2ca02683abadf43f93c3e00 100644 (file)
--- a/src/journal/journald.c
+++ b/src/journal/journald.c
@@ -329,7 +329,10 @@ static void server_rotate(Server *s) {
         if (s->runtime_journal) {
                 r = journal_file_rotate(&s->runtime_journal);
                 if (r < 0)
-                        log_error("Failed to rotate %s: %s", s->runtime_journal->path, strerror(-r));
+                        if (s->runtime_journal)
+                                log_error("Failed to rotate %s: %s", s->runtime_journal->path, strerror(-r));
+                        else
+                                log_error("Failed to create new runtime journal: %s", strerror(-r));
                 else
                         server_fix_perms(s, s->runtime_journal, 0);
         }
@@ -337,7 +340,11 @@ static void server_rotate(Server *s) {
         if (s->system_journal) {
                 r = journal_file_rotate(&s->system_journal);
                 if (r < 0)
-                        log_error("Failed to rotate %s: %s", s->system_journal->path, strerror(-r));
+                        if (s->system_journal)
+                                log_error("Failed to rotate %s: %s", s->system_journal->path, strerror(-r));
+                        else
+                                log_error("Failed to create new system journal: %s", strerror(-r));
+
                 else
                         server_fix_perms(s, s->system_journal, 0);
         }
@@ -345,7 +352,10 @@ static void server_rotate(Server *s) {
         HASHMAP_FOREACH_KEY(f, k, s->user_journals, i) {
                 r = journal_file_rotate(&f);
                 if (r < 0)
-                        log_error("Failed to rotate %s: %s", f->path, strerror(-r));
+                        if (f->path)
+                                log_error("Failed to rotate %s: %s", f->path, strerror(-r));
+                        else
+                                log_error("Failed to create user journal: %s", strerror(-r));
                 else {
                         hashmap_replace(s->user_journals, k, f);
                         server_fix_perms(s, s->system_journal, PTR_TO_UINT32(k));