From 889e396046a8a52c16beee7aa6395dc32f854fd1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= <zbyszek@in.waw.pl>
Date: Wed, 16 May 2018 17:21:51 +0200
Subject: [PATCH] shared/logs-show: export show_journal()

This is a nice function to output some journal entries without much ado.
---
 src/shared/logs-show.c | 35 ++++++++++++++++++++---------------
 src/shared/logs-show.h |  9 +++++++++
 2 files changed, 29 insertions(+), 15 deletions(-)

diff --git a/src/shared/logs-show.c b/src/shared/logs-show.c
index e1d59209d7..50326fde5d 100644
--- a/src/shared/logs-show.c
+++ b/src/shared/logs-show.c
@@ -1119,14 +1119,15 @@ static int maybe_print_begin_newline(FILE *f, OutputFlags *flags) {
         return 0;
 }
 
-static int show_journal(FILE *f,
-                        sd_journal *j,
-                        OutputMode mode,
-                        unsigned n_columns,
-                        usec_t not_before,
-                        unsigned how_many,
-                        OutputFlags flags,
-                        bool *ellipsized) {
+int show_journal(
+                FILE *f,
+                sd_journal *j,
+                OutputMode mode,
+                unsigned n_columns,
+                usec_t not_before,
+                unsigned how_many,
+                OutputFlags flags,
+                bool *ellipsized) {
 
         int r;
         unsigned line = 0;
@@ -1137,14 +1138,18 @@ static int show_journal(FILE *f,
         assert(mode >= 0);
         assert(mode < _OUTPUT_MODE_MAX);
 
-        /* Seek to end */
-        r = sd_journal_seek_tail(j);
-        if (r < 0)
-                return log_error_errno(r, "Failed to seek to tail: %m");
+        if (how_many == (unsigned) -1)
+                need_seek = true;
+        else {
+                /* Seek to end */
+                r = sd_journal_seek_tail(j);
+                if (r < 0)
+                        return log_error_errno(r, "Failed to seek to tail: %m");
 
-        r = sd_journal_previous_skip(j, how_many);
-        if (r < 0)
-                return log_error_errno(r, "Failed to skip previous: %m");
+                r = sd_journal_previous_skip(j, how_many);
+                if (r < 0)
+                        return log_error_errno(r, "Failed to skip previous: %m");
+        }
 
         for (;;) {
                 for (;;) {
diff --git a/src/shared/logs-show.h b/src/shared/logs-show.h
index 49caa4cb39..68e234a0ef 100644
--- a/src/shared/logs-show.h
+++ b/src/shared/logs-show.h
@@ -28,6 +28,15 @@ int show_journal_entry(
                 char **output_fields,
                 size_t highlight[2],
                 bool *ellipsized);
+int show_journal(
+                FILE *f,
+                sd_journal *j,
+                OutputMode mode,
+                unsigned n_columns,
+                usec_t not_before,
+                unsigned how_many,
+                OutputFlags flags,
+                bool *ellipsized);
 
 int add_match_this_boot(sd_journal *j, const char *machine);