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authorLennart Poettering <lennart@poettering.net>2016-04-25 16:23:29 +0200
committerLennart Poettering <lennart@poettering.net>2016-04-25 16:34:55 +0200
commitc4fbc6b6e4017199717b2b8dac3d790ffd8934cc (patch)
treee15c92a01ef1dbf475a3ce9f2d8f203f61a7d554 /src
parent4f4d6ee4be1c5d3bb2f3ebce7d2d332285963830 (diff)
journalctl: add some explanatory comments to get_boots()
Diffstat (limited to 'src')
-rw-r--r--src/journal/journalctl.c23
1 files changed, 16 insertions, 7 deletions
diff --git a/src/journal/journalctl.c b/src/journal/journalctl.c
index c9a2c3812d..d764ba12aa 100644
--- a/src/journal/journalctl.c
+++ b/src/journal/journalctl.c
@@ -1103,16 +1103,16 @@ static int get_boots(
return r;
if (advance_older)
- r = sd_journal_seek_head(j);
+ r = sd_journal_seek_head(j); /* seek to oldest */
else
- r = sd_journal_seek_tail(j);
+ r = sd_journal_seek_tail(j); /* seek to newest */
if (r < 0)
return r;
if (advance_older)
- r = sd_journal_next(j);
+ r = sd_journal_next(j); /* read the oldest entry */
else
- r = sd_journal_previous(j);
+ r = sd_journal_previous(j); /* read the most recently added entry */
if (r < 0)
return r;
else if (r == 0)
@@ -1121,15 +1121,24 @@ static int get_boots(
count = 1;
goto finish;
}
+
+ /* At this point the read pointer is positioned at the oldest/newest occurence of the reference boot
+ * ID. After flushing the matches, one more invocation of _previous()/_next() will hence place us at
+ * the following entry, which must then have an older/newer boot ID */
} else {
+
if (advance_older)
- r = sd_journal_seek_tail(j);
+ r = sd_journal_seek_tail(j); /* seek to newest */
else
- r = sd_journal_seek_head(j);
+ r = sd_journal_seek_head(j); /* seek to oldest */
if (r < 0)
return r;
- /* No sd_journal_next/previous here. */
+ /* No sd_journal_next()/_previous() here.
+ *
+ * At this point the read pointer is positioned after the newest/before the oldest entry in the whole
+ * journal. The next invocation of _previous()/_next() will hence position us at the newest/oldest
+ * entry we have. */
}
for (;;) {