add pkexec support

closes https://github.com/mate-desktop/mate-system-monitor/issues/85

try pkexec before trying gksu for killing other users' processes
or renicing a process. actual kill and renice commands are launched
via helper tool (see discussion at https://bugzilla.gnome.org/491462).

code is ported from gnome-system-monitor with some changes (e.g. helper
tool code is in tools/ dir instead of scripts/ - it's not a script).

for reference - relevant upstream commits:
https://git.gnome.org/browse/gnome-system-monitor/commit/?id=ccbff2a4293e43d6ea24fbf13477b10f58cd5212
https://git.gnome.org/browse/gnome-system-monitor/commit/?id=2b4308d9fc2b2e367030629e79b531c4f9ae3d0a
https://git.gnome.org/browse/gnome-system-monitor/commit/?id=971b3c704dea49b22c1038f200933c5b3b35ece1
https://git.gnome.org/browse/gnome-system-monitor/commit/?id=c234b2a75dac454b818f1f40d302cf12f1a33aa2
https://git.gnome.org/browse/gnome-system-monitor/commit/?id=4cda3529e418098b35f7444d79ba421eb5403afc
https://git.gnome.org/browse/gnome-system-monitor/commit/?id=ab7bd8aef7300eeb3835fdef9a2a1eefe7281631
https://git.gnome.org/browse/gnome-system-monitor/commit/?id=79eccf0cecbca237f4f911681438c33932da63e2
https://git.gnome.org/browse/gnome-system-monitor/commit/?id=a3bf3a7f56cf02c6a127aa168c570230e9fad356

4 files changed, 51 insertions, 1 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index 38588e9..2140770 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -4,6 +4,7 @@ AM_CPPFLAGS = \
 	-DPROCMAN_DATADIR=\""$(datadir)/procman/"\" \
 	-DMATELOCALEDIR=\""$(datadir)/locale"\" \
 	-DDATADIR=\""$(datadir)"\" \
+	-DLIBEXEC_DIR=\""$(pkglibexecdir)"\" \
 	@PROCMAN_CFLAGS@ \
 	@SYSTEMD_CFLAGS@
 
@@ -28,6 +29,7 @@ mate_system_monitor_cpp_files = \
 	selinux.cpp \
 	cgroups.cpp \
 	procman_gksu.cpp \
+	procman_pkexec.cpp \
 	sysinfo.cpp \
 	lsof.cpp \
 	selection.cpp \
diff --git a/src/procdialogs.cpp b/src/procdialogs.cpp
index 96cf39c..0a4be65 100644
--- a/src/procdialogs.cpp
+++ b/src/procdialogs.cpp
@@ -34,6 +34,7 @@
 #include "load-graph.h"
 #include "settings-keys.h"
 #include "procman_gksu.h"
+#include "procman_pkexec.h"
 #include "cgroups.h"
 
 
@@ -894,7 +895,9 @@ procdialog_create_root_password_dialog(ProcmanActionType type,
 
     procman_debug("Trying to run '%s' as root", command);
 
-    if (procman_has_gksu())
+    if (procman_has_pkexec())
+        ret = procman_pkexec_create_root_password_dialog(command);
+    else if (procman_has_gksu())
         ret = procman_gksu_create_root_password_dialog(command);
 
     g_free(command);
diff --git a/src/procman_pkexec.cpp b/src/procman_pkexec.cpp
new file mode 100644
index 0000000..f67be6a
--- /dev/null
+++ b/src/procman_pkexec.cpp
@@ -0,0 +1,33 @@
+#include <config.h>
+
+#include "procman_pkexec.h"
+
+gboolean
+procman_pkexec_create_root_password_dialog (const char *command)
+{
+    gchar *command_line;
+    gboolean success;
+    GError *error = NULL;
+
+    command_line = g_strdup_printf ("pkexec --disable-internal-agent %s/msm-%s",
+                                    LIBEXEC_DIR, command);
+    success = g_spawn_command_line_sync (command_line, NULL, NULL, NULL, &error);
+    g_free (command_line);
+
+    if (!success) {
+        g_critical ("Could not run pkexec (\"%s\") : %s\n",
+                    command, error->message);
+        g_error_free (error);
+        return FALSE;
+    }
+
+    g_debug ("pkexec did fine\n");
+    return TRUE;
+}
+
+gboolean
+procman_has_pkexec (void)
+{
+    return g_file_test("/usr/bin/pkexec", G_FILE_TEST_EXISTS);
+}
+
diff --git a/src/procman_pkexec.h b/src/procman_pkexec.h
new file mode 100644
index 0000000..d453f69
--- /dev/null
+++ b/src/procman_pkexec.h
@@ -0,0 +1,12 @@
+#ifndef _PROCMAN_PKEXEC_H_
+#define _PROCMAN_PKEXEC_H_
+
+#include <glib.h>
+
+gboolean
+procman_pkexec_create_root_password_dialog(const char *command);
+
+gboolean
+procman_has_pkexec(void) G_GNUC_CONST;
+
+#endif /* _PROCMAN_PKEXEC_H_ */