From b1d3aef655509d7debc651ff54226e4b067db3f4 Mon Sep 17 00:00:00 2001
From: Mel Gorman <mgorman@suse.de>
Date: Wed, 12 Jun 2013 15:53:26 +0100
Subject: [PATCH] Give an option of running in foreground mode

systemd forking service type smells of something unfortunate apparently
and a desire was expressed to have it run as a simple service with
a foreground mode option. This patch implements a -F flag and uses it
with systemd.

Signed-off-by: Mel Gorman <mgorman@suse.de>
---
 numad.8       |  5 ++++-
 numad.c       | 30 ++++++++++++++++++++----------
 numad.service |  5 ++---
 3 files changed, 26 insertions(+), 14 deletions(-)

diff --git a/numad.8 b/numad.8
index 2c46f55..73a0bc9 100644
--- a/numad.8
+++ b/numad.8
@@ -5,7 +5,7 @@ numad \- A user\-level daemon that provides placement advice and process
 management for efficient use of CPUs and memory on systems with NUMA topology.
 .SH "SYNTAX"
 .LP 
-numad [\fI\-dhvV\fP]
+numad [\fI\-dFhvV\fP]
 .br 
 .LP 
 numad  [\fI\-D non-standard-cgroup-mount-point\fP]
@@ -61,6 +61,9 @@ Debug output in log, sets the log level to LOG_DEBUG.  Same effect as \fI\-l 7\f
 \fB\-D\fR <\fInon-standard-cgroup-mount-point\fP>
 This option can be used to communicate a non-standard cgroup mount point to
 numad.  This is not normally necessary.
+.TP
+\fB\-F\fR
+Run in foreground mode, do not daemonize\fP.
 .TP 
 \fB\-h\fR
 Display usage help information and then exit.
diff --git a/numad.c b/numad.c
index d08b622..f6581c0 100644
--- a/numad.c
+++ b/numad.c
@@ -680,6 +680,7 @@ void print_usage_and_exit(char *prog_name) {
     fprintf(stderr, "Usage: %s <options> ...\n", prog_name);
     fprintf(stderr, "-d for debug logging (same effect as '-l 7')\n");
     fprintf(stderr, "-D <CGROUP_MOUNT_POINT> to specify cgroup mount point\n");
+    fprintf(stderr, "-F to run in the foreground\n");
     fprintf(stderr, "-h to print this usage info\n");
     fprintf(stderr, "-i [<MIN>:]<MAX> to specify interval seconds\n");
     fprintf(stderr, "-K 1  to keep interleaved memory spread across nodes\n");
@@ -2145,8 +2146,9 @@ int main(int argc, char *argv[]) {
     int v_flag = 0;
     int w_flag = 0;
     int x_flag = 0;
+    int F_flag = 0;
     long list_pid = 0;
-    while ((opt = getopt(argc, argv, "dD:hi:K:l:p:r:S:u:vVw:x:")) != -1) {
+    while ((opt = getopt(argc, argv, "dFD:hi:K:l:p:r:S:u:vVw:x:")) != -1) {
         switch (opt) {
         case 'd':
             d_flag = 1;
@@ -2155,6 +2157,9 @@ int main(int argc, char *argv[]) {
         case 'D':
             cpuset_dir_list[0] = strdup(optarg);
             break;
+        case 'F':
+            F_flag = 1;
+            break;
         case 'h':
             print_usage_and_exit(argv[0]);
             break;
@@ -2278,15 +2283,20 @@ int main(int argc, char *argv[]) {
     } else if (max_interval > 0) {
         // Start the numad daemon...
         check_prereqs(argv[0]);
-        // Daemonize self...
-        daemon_pid = fork();
-        if (daemon_pid < 0) { numad_log(LOG_CRIT, "fork() failed\n"); exit(EXIT_FAILURE); }
-        // Parent process now exits
-        if (daemon_pid > 0) { exit(EXIT_SUCCESS); }
-        // Child process continues...
-        umask(S_IWGRP | S_IWOTH); // Reset the file mode
-        int sid = setsid();  // Start a new session
-        if (sid < 0) { numad_log(LOG_CRIT, "setsid() failed\n"); exit(EXIT_FAILURE); }
+
+        // Daemonize self if requested
+        if (F_flag == 0) {
+                daemon_pid = fork();
+                if (daemon_pid < 0) { numad_log(LOG_CRIT, "fork() failed\n"); exit(EXIT_FAILURE); }
+                // Parent process now exits
+                if (daemon_pid > 0) { exit(EXIT_SUCCESS); }
+
+                // Child process continues...
+                umask(S_IWGRP | S_IWOTH); // Reset the file mode
+                int sid = setsid();  // Start a new session
+                if (sid < 0) { numad_log(LOG_CRIT, "setsid() failed\n"); exit(EXIT_FAILURE); }
+        }
+
         if ((chdir("/")) < 0) { numad_log(LOG_CRIT, "chdir() failed"); exit(EXIT_FAILURE); }
         daemon_pid = register_numad_pid();
         if (daemon_pid != getpid()) {
diff --git a/numad.service b/numad.service
index d0c8c5b..0223ca9 100644
--- a/numad.service
+++ b/numad.service
@@ -2,10 +2,9 @@
 Description=numad - The NUMA daemon that manages application locality.
 
 [Service]
-Type=forking
-PIDFile=/var/run/numad.pid
+Type=simple
 EnvironmentFile=/etc/numad.conf
-ExecStart=/usr/sbin/numad -i $INTERVAL
+ExecStart=/usr/sbin/numad -i $INTERVAL -F
 ExecStop=/usr/sbin/numad -i 0
 
 [Install]