From a8ca04cfa31068e4599c97a4cf83112bde5a1132 Mon Sep 17 00:00:00 2001
From: "Dmitry V. Levin" <ldv@altlinux.org>
Date: Mon, 18 Mar 2019 19:06:47 +0000
Subject: [PATCH] strace-log-merge: fix error diagnostics

* strace-log-merge: Print error diagnostics and exit with a non-zero
status in case of no strace output.
* NEWS: Mention this fix.
* tests/strace-log-merge-error.test: New test.
* tests/Makefile.am (MISC_TESTS): Add it.

Fixes: v4.21~287 "strace-log-merge: work around corner cases of strace -ttt parsing"
---
 NEWS                              |  1 +
 strace-log-merge                  |  8 ++++---
 tests/Makefile.am                 |  1 +
 tests/strace-log-merge-error.test | 37 +++++++++++++++++++++++++++++++
 4 files changed, 44 insertions(+), 3 deletions(-)
 create mode 100755 tests/strace-log-merge-error.test

diff --git a/NEWS b/NEWS
index 3b6224b5..3bdfd0e0 100644
--- a/NEWS
+++ b/NEWS
@@ -35,6 +35,7 @@ Noteworthy changes in release ?.?? (????-??-??)
   * Fixed build in --with-libiberty=yes mode.
   * Fixed potential NULL dereference during printing of line continuation
     for syscalls that haven't been decoded.
+  * Fixed strace-log-merge error diagnostics.
 
 Noteworthy changes in release 4.26 (2018-12-26)
 ===============================================
diff --git a/strace-log-merge b/strace-log-merge
index 87998c53..9ef5705b 100755
--- a/strace-log-merge
+++ b/strace-log-merge
@@ -3,7 +3,7 @@
 # This script processes strace -ff -tt output.  It merges the contents of all
 # STRACE_LOG.PID files and sorts them, printing result on the standard output.
 #
-# Copyright (c) 2012-2018 The strace developers.
+# Copyright (c) 2012-2019 The strace developers.
 #
 # SPDX-License-Identifier: LGPL-2.1-or-later
 
@@ -44,8 +44,10 @@ for file in "$logfile".*; do
 	# grep -v '^$' removes empty lines which may result.
 	sed -n "s/^\($dd:\)\?\($dd:\)\?\($ds\.\)\?$ds /\2\4\6\7 $pid \0/p" < "$file"
 	echo
-done \
-| sort -s -n -k1,1 | sed -n 's/^[0-9][0-9]* //p'
+done |
+	sort -s -n -k1,1 |
+	sed -n 's/^[0-9][0-9]* //p' |
+	grep -v '^$'
 
 rc=$?
 [ $rc -eq 1 ] &&
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 68da797a..553ff5e1 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -341,6 +341,7 @@ MISC_TESTS = \
 	strace-T.test \
 	strace-V.test \
 	strace-ff.test \
+	strace-log-merge-error.test \
 	strace-r.test \
 	strace-t.test \
 	strace-tt.test \
diff --git a/tests/strace-log-merge-error.test b/tests/strace-log-merge-error.test
new file mode 100755
index 00000000..35a2de82
--- /dev/null
+++ b/tests/strace-log-merge-error.test
@@ -0,0 +1,37 @@
+#!/bin/sh
+#
+# Check strace-log-merge error diagnostics.
+#
+# Copyright (c) 2019 The strace developers.
+# All rights reserved.
+#
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+. "${srcdir=.}/init.sh"
+
+rm -f -- "$LOG".[0-9]*
+echo "strace-log-merge: $LOG: strace output not found" > "$EXP"
+
+check_strace_log_merge()
+{
+	"$srcdir"/../strace-log-merge "$LOG" > "$OUT" 2> "$LOG"
+	rc=$?
+
+	[ $rc -gt 0 ] ||
+		dump_log_and_fail_with 'strace-log-merge unexpectedly succeeded'
+
+	[ ! -s "$OUT" ] ||
+		dump_log_and_fail_with 'strace-log-merge unexpectedly produced output'
+
+	match_diff "$LOG" "$EXP" 'strace-log-merge error diagnostics mismatch'
+}
+
+check_strace_log_merge
+
+echo '1234567890.123456 +++ exited with 0 +++' > "$LOG".0
+check_strace_log_merge
+
+echo > "$LOG".1
+check_strace_log_merge
+
+rm -f -- "$LOG".[0-9]*
-- 
2.50.1