From 22a8744476dff7763cd94954bd8f96fbdfc0d251 Mon Sep 17 00:00:00 2001
From: Alexander Barton <alex@barton.de>
Date: Mon, 1 Apr 2024 21:38:21 +0200
Subject: [PATCH] Test suite: simplify and enhance getpid.sh

- Try to only search for processes of the current user.
- Prefer using pgrep (in addition to pidof) when available.
- Streamline system overrides.
- Get rid of HEAD_FLAGS: all systems so far support "-1".
- Use "ps -o pid,comm" as the default, which is POSIX.1.
- Use "sort -r" to hopefully get the newest (=highest) PID, which is the
  case on older systems not using randomized PIDs at least.
---
 src/testsuite/getpid.sh | 69 ++++++++++++++++++++++++-----------------
 1 file changed, 40 insertions(+), 29 deletions(-)

diff --git a/src/testsuite/getpid.sh b/src/testsuite/getpid.sh
index 55997ad8..465def64 100755
--- a/src/testsuite/getpid.sh
+++ b/src/testsuite/getpid.sh
@@ -1,46 +1,57 @@
 #!/bin/sh
 # ngIRCd Test Suite
+#
+# Try to detect the PID of a running process of the current user.
+#
 
 set -u
 
 # did we get a name?
-[ $# -ne 1 ] && exit 1
-
-[ -x /bin/pidof ] && exec /bin/pidof -s "$1"
+if [ $# -ne 1 ]; then
+	echo "Usage: $0 <name>" >&2
+	exit 1
+fi
 
-# detect flags for "ps" and "head"
 UNAME=`uname`
-if [ $UNAME = "FreeBSD" ]; then
-	PS_FLAGS="-a"; PS_PIDCOL="1"; HEAD_FLAGS="-n 1"
-elif [ $UNAME = "A/UX" ]; then
-	PS_FLAGS="-af"; PS_PIDCOL="2"; HEAD_FLAGS="-1"
-elif [ $UNAME = "GNU" ]; then
-	PS_FLAGS="-ax"; PS_PIDCOL="2"; HEAD_FLAGS="-n 1"
-elif [ $UNAME = "Haiku" ]; then
-	PS_FLAGS="-o Id -o Team"; PS_PIDCOL="1"; HEAD_FLAGS="-1"
-elif [ $UNAME = "Linux" ]; then
-	PS_FLAGS="ax"; PS_PIDCOL="1"; HEAD_FLAGS="-n 1"
-elif [ $UNAME = "SunOS" ]; then
-	PS_FLAGS="-af"; PS_PIDCOL=2; HEAD_FLAGS="-n 1"
-else
-	PS_FLAGS="-af"; PS_PIDCOL="2"; HEAD_FLAGS="-n 1"
-	ps $PS_FLAGS >/dev/null 2>&1
-	if [ $? -ne 0 ]; then PS_FLAGS="a"; PS_PIDCOL="1"; fi
+
+# Use pgrep(1) whenever possible
+if [ -x /usr/bin/pgrep ]; then
+	case "$UNAME" in
+		"FreeBSD")
+			PGREP_FLAGS="-a"
+			;;
+		*)
+			PGREP_FLAGS=""
+	esac
+	exec /usr/bin/pgrep $PGREP_FLAGS -n -u "$LOGNAME" "$1"
 fi
 
-# debug output
-#echo "$0: UNAME=$UNAME"
-#echo "$0: PS_FLAGS=$PS_FLAGS"
-#echo "$0: PS_PIDCOL=$PS_PIDCOL"
-#echo "$0: HEAD_FLAGS=$HEAD_FLAGS"
+# pidof(1) could be a good alternative on elder Linux systems
+if [ -x /bin/pidof ]; then
+	exec /bin/pidof -s "$1"
+fi
+
+# fall back to ps(1) and parse its output:
+# detect flags for "ps" and "head"
+PS_PIDCOL=1
+case "$UNAME" in
+	"A/UX"|"GNU"|"SunOS")
+		PS_FLAGS="-a"; PS_PIDCOL=2
+		;;
+	"Haiku")
+		PS_FLAGS="-o Id -o Team"
+		;;
+	*)
+		# Linux (GNU coreutils), Free/Net/OpenBSD, ...
+		PS_FLAGS="-o pid,comm"
+esac
 
 # search PID
 ps $PS_FLAGS >procs.tmp
-cat procs.tmp | \
-	grep -v "$0" | grep "$1" | \
+grep -v "$$" procs.tmp | grep "$1" | \
 	awk "{print \$$PS_PIDCOL}" | \
-	sort -n >pids.tmp
-pid=`head $HEAD_FLAGS pids.tmp`
+	sort -nr >pids.tmp
+pid=`head -1 pids.tmp`
 rm -rf procs.tmp pids.tmp
 
 # validate PID
-- 
2.39.2