build-sys: add setcap or setuid to ping when installing

Capacity is preferred, but when that does not work make ping to be setuid
root binary, that is the legacy way to install this software.

Signed-off-by: Sami Kerola <kerolasa@iki.fi>

2 files changed, 37 insertions, 0 deletions

diff --git a/build-aux/setcap-setuid.sh b/build-aux/setcap-setuid.sh
new file mode 100755
index 0000000..dba6c03
--- /dev/null
+++ b/build-aux/setcap-setuid.sh
@@ -0,0 +1,25 @@
+#!/bin/sh
+#
+# Meson install script to setcap or setuid to an executable.
+
+exec_path="$1/$2"
+perm_type="$3"
+setcap="$4"
+
+case "$perm_type" in
+	'caps')
+		echo "$0: calling: $setcap cap_net_raw+ep $exec_path"
+		"$setcap" 'cap_net_raw+ep' "$exec_path" || true
+	;;
+	'setuid')
+		echo "$0: changing $exec_path to be setuid root executable"
+		chown root "$exec_path" || true
+		chmod u+s "$exec_path" || true
+	;;
+	*)
+		echo "$0: unexpected argument: $perm_type"
+		exit 1
+	;;
+esac
+
+exit 0
diff --git a/meson.build b/meson.build
index d1c5e80..cb1adc3 100644
--- a/meson.build
+++ b/meson.build
@@ -167,6 +167,18 @@ if build_ping == true
 	executable('ping', ['ping.c', 'ping_common.c', 'ping6_common.c', git_version_h],
 		dependencies : [m_dep, cap_dep, idn_dep, crypto_dep, resolv_dep],
 		install: true)
+	setcap = find_program('setcap', '/usr/sbin/setcap', '/sbin/setcap', required : false)
+	if cap_dep.found() and setcap.found()
+		perm_type = 'caps'
+	else
+		perm_type = 'setuid'
+	endif
+	meson.add_install_script('build-aux/setcap-setuid.sh',
+		join_paths(get_option('prefix'), get_option('bindir')),
+		'ping',
+		perm_type,
+		setcap.path()
+	)
 endif
 
 if build_tracepath == true