From 360af4cf6f18469df97c11af4cd5696e0ca8b3ef Mon Sep 17 00:00:00 2001

From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= <zbyszek@in.waw.pl>

Date: Thu, 9 Oct 2014 22:44:29 -0400

Subject: [PATCH] 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.

---

 src/journal/journal-internal.h |  4 ++++

 src/journal/sd-journal.c       | 18 ++++++++++++------

 2 files changed, 16 insertions(+), 6 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;

diff --git a/src/journal/sd-journal.c b/src/journal/sd-journal.c

index 1fc9f01d0a..b72a0867e7 100644

--- a/src/journal/sd-journal.c

+++ b/src/journal/sd-journal.c

@@ -1375,8 +1375,11 @@ static void remove_file_real(sd_journal *j, JournalFile *f) {

         }

         if (j->unique_file == f) {

-                j->unique_file = NULL;

+                /* Jump to the next unique_file or NULL if that one was last */

+                j->unique_file = hashmap_next(j->files, j->unique_file->path);

                 j->unique_offset = 0;

+                if (!j->unique_file)

+                        j->unique_file_lost = true;

         }

         journal_file_close(f);

@@ -2490,6 +2493,7 @@ _public_ int sd_journal_query_unique(sd_journal *j, const char *field) {

         j->unique_field = f;

         j->unique_file = NULL;

         j->unique_offset = 0;

+        j->unique_file_lost = false;

         return 0;

 }

@@ -2506,9 +2510,13 @@ _public_ int sd_journal_enumerate_unique(sd_journal *j, const void **data, size_

         k = strlen(j->unique_field);

         if (!j->unique_file) {

+                if (j->unique_file_lost)

+                        return 0;

+

                 j->unique_file = hashmap_first(j->files);

                 if (!j->unique_file)

                         return 0;

+

                 j->unique_offset = 0;

         }

@@ -2538,13 +2546,10 @@ _public_ int sd_journal_enumerate_unique(sd_journal *j, const void **data, size_

                 /* We reached the end of the list? Then start again, with the next file */

                 if (j->unique_offset == 0) {

-                        JournalFile *n;

-

-                        n = hashmap_next(j->files, j->unique_file->path);

-                        if (!n)

+                        j->unique_file = hashmap_next(j->files, j->unique_file->path);

+                        if (!j->unique_file)

                                 return 0;

-                        j->unique_file = n;

                         continue;

                 }

@@ -2632,6 +2637,7 @@ _public_ void sd_journal_restart_unique(sd_journal *j) {

         j->unique_file = NULL;

         j->unique_offset = 0;

+        j->unique_file_lost = false;

 }

 _public_ int sd_journal_reliable_fd(sd_journal *j) {