Add systemd readiness notification support

Bug-Debian: https://bugs.debian.org/778913
Forwarded: no
Last-Update: 2017-08-22

Patch-Name: systemd-readiness.patch

Gbp-Pq: Name systemd-readiness.patch

configure.ac

@@ -4664,6 +4664,29 @@ AC_ARG_WITH([kerberos5],
 AC_SUBST([GSSLIBS])
 AC_SUBST([K5LIBS])
 
+# Check whether user wants systemd support
+SYSTEMD_MSG="no"
+AC_ARG_WITH(systemd,
+	[  --with-systemd          Enable systemd support],
+	[ if test "x$withval" != "xno" ; then
+		AC_PATH_TOOL([PKGCONFIG], [pkg-config], [no])
+		if test "$PKGCONFIG" != "no"; then
+			AC_MSG_CHECKING([for libsystemd])
+			if $PKGCONFIG --exists libsystemd; then
+				SYSTEMD_CFLAGS=`$PKGCONFIG --cflags libsystemd`
+				SYSTEMD_LIBS=`$PKGCONFIG --libs libsystemd`
+				CPPFLAGS="$CPPFLAGS $SYSTEMD_CFLAGS"
+				SSHDLIBS="$SSHDLIBS $SYSTEMD_LIBS"
+				AC_MSG_RESULT([yes])
+				AC_DEFINE(HAVE_SYSTEMD, 1, [Define if you want systemd support.])
+				SYSTEMD_MSG="yes"
+			else
+				AC_MSG_RESULT([no])
+			fi
+		fi
+	fi ]
+)
+
 # Looking for programs, paths and files
 
 PRIVSEP_PATH=/var/empty
@@ -5476,6 +5499,7 @@ echo "                   libldns support: $LDNS_MSG"
 echo "  Solaris process contract support: $SPC_MSG"
 echo "           Solaris project support: $SP_MSG"
 echo "         Solaris privilege support: $SPP_MSG"
+echo "                   systemd support: $SYSTEMD_MSG"
 echo "       IP address in \$DISPLAY hack: $DISPLAY_HACK_MSG"
 echo "           Translate v4 in v6 hack: $IPV4_IN6_HACK_MSG"
 echo "                  BSD Auth support: $BSD_AUTH_MSG"

sshd.c

@@ -85,6 +85,10 @@
 #include <prot.h>
 #endif
 
+#ifdef HAVE_SYSTEMD
+#include <systemd/sd-daemon.h>
+#endif
+
 #include "xmalloc.h"
 #include "ssh.h"
 #include "ssh2.h"
@@ -2027,6 +2031,11 @@ main(int ac, char **av)
 			}
 		}
 
+#ifdef HAVE_SYSTEMD
+		/* Signal systemd that we are ready to accept connections */
+		sd_notify(0, "READY=1");
+#endif
+
 		/* Accept a connection and return in a forked child */
 		server_accept_loop(&sock_in, &sock_out,
 		    &newsock, config_s);