From b734e8c1e8b8e76703b5614b393c89b59080e836 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: enhance pid formatting

* strace-log-merge (max_suffix_length): New variable.
(iterate_logfiles, process_suffix, process_logfile): New functions.
Use them to choose the optimum width for pid column.
* NEWS: Mention this enhancement.
* tests/strace-log-merge-suffix.test: New test.
* tests/Makefile.am (MISC_TESTS): Add it.
---
 NEWS                               |  1 +
 strace-log-merge                   | 51 +++++++++++++++++++++++++-----
 tests/Makefile.am                  |  1 +
 tests/strace-log-merge-suffix.test | 29 +++++++++++++++++
 4 files changed, 74 insertions(+), 8 deletions(-)
 create mode 100755 tests/strace-log-merge-suffix.test

diff --git a/NEWS b/NEWS
index 3bdfd0e0..96daad3e 100644
--- a/NEWS
+++ b/NEWS
@@ -20,6 +20,7 @@ Noteworthy changes in release ?.?? (????-??-??)
   * Enhanced xlat styles support configured by -X option.
   * Enhanced decoding of bpf syscall.
   * Enhanced decoding of PTRACE_PEEKUSER and PTRACE_POKEUSER on hppa.
+  * Enhanced pid formatting in strace-log-merge output.
   * Wired up kexec_file_load and rseq syscalls on aarch64, arc, metag, nios2,
     or1k, riscv, and tile architectures.
   * Updated lists of BPF_*, BTRFS_*, FAN_*, IFLA_*, KERN_*, KVM_CAP_*, NDA_*,
diff --git a/strace-log-merge b/strace-log-merge
index 9ef5705b..93d87ba2 100755
--- a/strace-log-merge
+++ b/strace-log-merge
@@ -33,18 +33,53 @@ fi
 
 logfile=$1
 
-for file in "$logfile".*; do
-	[ -f "$file" ] || continue
-	suffix=${file#"$logfile".}
-	[ "$suffix" -gt 0 ] 2> /dev/null ||
-		continue
-	pid=$(printf "%-5s" $suffix)
+iterate_logfiles()
+{
+	local file suffix
+
+	for file in "$logfile".*; do
+		[ -f "$file" ] || continue
+		suffix=${file#"$logfile".}
+		[ "$suffix" -gt 0 ] 2> /dev/null ||
+			continue
+		"$@" "$suffix" "$file"
+	done
+}
+
+max_suffix_length=0
+process_suffix()
+{
+	local suffix len
+	suffix="$1"; shift
+
+	len=${#suffix}
+	if [ $len -gt $max_suffix_length ]; then
+		max_suffix_length=$len
+	fi
+}
+
+process_logfile()
+{
+	local suffix file pid
+	suffix="$1"; shift
+	file="$1"; shift
+
+	pid=$(printf "%-*s" $max_suffix_length $suffix)
 	# Some strace logs have last line which is not '\n' terminated,
 	# so add extra newline to every file.
-	# grep -v '^$' removes empty lines which may result.
+	# Empty lines are removed later.
 	sed -n "s/^\($dd:\)\?\($dd:\)\?\($ds\.\)\?$ds /\2\4\6\7 $pid \0/p" < "$file"
 	echo
-done |
+}
+
+iterate_logfiles process_suffix
+
+[ $max_suffix_length -gt 0 ] || {
+	echo >&2 "${0##*/}: $logfile: strace output not found"
+	exit 1
+}
+
+iterate_logfiles process_logfile |
 	sort -s -n -k1,1 |
 	sed -n 's/^[0-9][0-9]* //p' |
 	grep -v '^$'
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 553ff5e1..9e99aff2 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -342,6 +342,7 @@ MISC_TESTS = \
 	strace-V.test \
 	strace-ff.test \
 	strace-log-merge-error.test \
+	strace-log-merge-suffix.test \
 	strace-r.test \
 	strace-t.test \
 	strace-tt.test \
diff --git a/tests/strace-log-merge-suffix.test b/tests/strace-log-merge-suffix.test
new file mode 100755
index 00000000..51a2e5fb
--- /dev/null
+++ b/tests/strace-log-merge-suffix.test
@@ -0,0 +1,29 @@
+#!/bin/sh
+#
+# Check strace-log-merge pid formatting.
+#
+# 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 '3456789012.345678 +++ exited with 3 +++' > "$LOG".4294967295
+echo '1234567890.123456 +++ exited with 2 +++' > "$LOG".65535
+echo '2345678901.234567 +++ exited with 1 +++' > "$LOG".1
+
+cat > "$EXP" <<'EOF'
+65535      1234567890.123456 +++ exited with 2 +++
+1          2345678901.234567 +++ exited with 1 +++
+4294967295 3456789012.345678 +++ exited with 3 +++
+EOF
+
+"$srcdir"/../strace-log-merge "$LOG" > "$OUT" 2> "$LOG" ||
+	dump_log_and_fail_with 'strace-log-merge failed'
+
+match_diff "$OUT" "$EXP" 'strace-log-merge output mismatch'
+
+rm -f -- "$LOG".[0-9]*
-- 
2.40.0