File tgt-systemd-notification-support of Package tgt

From: Apollon Oikonomopoulos <apoikos@debian.org>
Date: Wed, 21 May 2014 11:43:27 +0900
Subject: systemd notification support
Git-commit: 63802aa754f4327833d9cb05cc26815f46b0fc9c
Patch-mainline: v1.0.48

tgtd may take some time to initialize before accepting management
commands. Since management commands are used to bring the targets up
during service startup, we have to make sure that tgtd is responsive
before proceeding. To this end, we add a call to sd_notify(3) right
before entering the event loop to signal systemd (if applicable) that
the main process is ready.

Systemd support with the relevant includes and linker flags is optional,
controlled by the SD_NOTIFY make flag.

Signed-off-by: Apollon Oikonomopoulos <apoikos@debian.org>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: Lee Duncan <lduncan@suse.com>
---
 Makefile     |    1 +
 usr/Makefile |    8 ++++++++
 usr/tgtd.c   |    4 ++++
 usr/tgtd.h   |    4 ++++
 4 files changed, 17 insertions(+)

--- a/Makefile
+++ b/Makefile
@@ -12,6 +12,7 @@ export VERSION PREFIX
 # Export the feature switches so sub-make knows about them
 export ISCSI_RDMA
 export CEPH_RBD
+export SD_NOTIFY
 
 .PHONY: all
 all: programs doc conf scripts
--- a/usr/Makefile
+++ b/usr/Makefile
@@ -17,6 +17,10 @@ ifneq ($(CEPH_RBD),)
 MODULES += bs_rbd.so
 endif
 
+ifneq ($(SD_NOTIFY),)
+CFLAGS += -DUSE_SYSTEMD
+endif
+
 ifneq ($(shell test -e /usr/include/sys/eventfd.h && test -e /usr/include/libaio.h && echo 1),)
 CFLAGS += -DUSE_EVENTFD
 TGTD_OBJS += bs_aio.o
@@ -46,6 +50,10 @@ CFLAGS += -DBSDIR=\"$(DESTDIR)$(libdir)/
 
 LIBS += -lpthread -ldl
 
+ifneq ($(SD_NOTIFY),)
+LIBS += -lsystemd-daemon
+endif
+
 PROGRAMS += tgtd tgtadm tgtimg
 TGTD_OBJS += tgtd.o mgmt.o target.o scsi.o log.o driver.o util.o work.o \
 		concat_buf.o parser.o spc.o sbc.o mmc.o osd.o scc.o smc.o \
--- a/usr/tgtd.c
+++ b/usr/tgtd.c
@@ -617,6 +617,10 @@ int main(int argc, char **argv)
 
 	bs_init();
 
+#ifdef USE_SYSTEMD
+	sd_notify(0, "READY=1\nSTATUS=Starting event loop...");
+#endif
+
 	event_loop();
 
 	lld_exit();
--- a/usr/tgtd.h
+++ b/usr/tgtd.h
@@ -5,6 +5,10 @@
 #include "scsi_cmnd.h"
 #include "tgtadm_error.h"
 
+#ifdef USE_SYSTEMD
+#include <systemd/sd-daemon.h>
+#endif
+
 struct concat_buf;
 
 #define NR_SCSI_OPCODES		256