From 634a6893abd524b5ccae0c9b8cd0957fa00abb24 Mon Sep 17 00:00:00 2001

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

Date: Fri, 18 Jul 2014 21:44:36 -0400

Subject: [PATCH] man,journal: add note about

 sd_journal_get_cutoff_monotonic_usec return value

Also modify the function itself to be a bit simpler to read.

(cherry picked from commit 1651e2c61e544de9ca947c8b3202552b1272ef57)

---

 man/sd_journal_get_cutoff_realtime_usec.xml | 36 ++++++++++++++++++-----------

 src/journal/sd-journal.c                    | 16 ++++++-------

 2 files changed, 31 insertions(+), 21 deletions(-)

diff --git a/man/sd_journal_get_cutoff_realtime_usec.xml b/man/sd_journal_get_cutoff_realtime_usec.xml

index 6df4b26e6f..ef987d85b0 100644

--- a/man/sd_journal_get_cutoff_realtime_usec.xml

+++ b/man/sd_journal_get_cutoff_realtime_usec.xml

@@ -74,25 +74,29 @@

                 <title>Description</title>

                 <para><function>sd_journal_get_cutoff_realtime_usec()</function>

-                gets the realtime (wallclock) timestamps of the first

-                and last entries accessible in the journal.  It takes

-                three arguments: the journal context object and two

-                pointers to 64-bit unsigned integers to store the

-                timestamps in. The timestamps are in microseconds

-                since the epoch,

+                retrieves the realtime (wallclock) timestamps of the

+                first and last entries accessible in the journal.  It

+                takes three arguments: the journal context object

+                <parameter>j</parameter> and two pointers

+                <parameter>from</parameter> and

+                <parameter>to</parameter> pointing at 64-bit unsigned

+                integers to store the timestamps in. The timestamps

+                are in microseconds since the epoch,

                 i.e. <constant>CLOCK_REALTIME</constant>. Either one

                 of the two timestamp arguments may be passed as

                 <constant>NULL</constant> in case the timestamp is not

                 needed, but not both.</para>

                 <para><function>sd_journal_get_cutoff_monotonic_usec()</function>

-                gets the monotonic timestamps of the first and last

-                entries accessible in the journal. It takes three

-                arguments: the journal context object, a 128-bit

-                identifier for the boot, and two pointers to 64-bit

-                unsigned integers to store the timestamps. The

-                timestamps are in microseconds since boot-up of the

-                specific boot,

+                retrieves the monotonic timestamps of the first and

+                last entries accessible in the journal. It takes three

+                arguments: the journal context object

+                <parameter>j</parameter>, a 128-bit identifier for the

+                boot <parameter>boot_id</parameter>, and two pointers

+                to 64-bit unsigned integers to store the timestamps,

+                <parameter>from</parameter> and

+                <parameter>to</parameter>. The timestamps are in

+                microseconds since boot-up of the specific boot,

                 i.e. <constant>CLOCK_MONOTONIC</constant>. Since the

                 monotonic clock begins new with every reboot it only

                 defines a well-defined point in time when used

@@ -113,6 +117,12 @@

                 <function>sd_journal_get_cutoff_monotonic_usec()</function>

                 return 1 on success, 0 if not suitable entries are in

                 the journal or a negative errno-style error code.</para>

+

+                <para>Locations pointed to by parameters

+                <parameter>from</parameter> and

+                <parameter>to</parameter> will be set only if the

+                return value is positive, and obviously, the

+                parameters are non-null.</para>

         </refsect1>

         <refsect1>

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

index ca805f83fe..15dae90925 100644

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

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

@@ -2390,7 +2390,7 @@ _public_ int sd_journal_get_cutoff_realtime_usec(sd_journal *j, uint64_t *from,

 _public_ int sd_journal_get_cutoff_monotonic_usec(sd_journal *j, sd_id128_t boot_id, uint64_t *from, uint64_t *to) {

         Iterator i;

         JournalFile *f;

-        bool first = true;

+        bool found = false;

         int r;

         assert_return(j, -EINVAL);

@@ -2409,21 +2409,21 @@ _public_ int sd_journal_get_cutoff_monotonic_usec(sd_journal *j, sd_id128_t boot

                 if (r == 0)

                         continue;

-                if (first) {

+                if (found) {

                         if (from)

-                                *from = fr;

+                                *from = MIN(fr, *from);

                         if (to)

-                                *to = t;

-                        first = false;

+                                *to = MAX(t, *to);

                 } else {

                         if (from)

-                                *from = MIN(fr, *from);

+                                *from = fr;

                         if (to)

-                                *to = MAX(t, *to);

+                                *to = t;

+                        found = true;

                 }

         }

-        return first ? 0 : 1;

+        return found;

 }

 void journal_print_header(sd_journal *j) {