[Xen-devel] [PATCH for-4.6 1/5] cxenstored: fix systemd socket activation

[Wei Liu <wei.liu2@xxxxxxxxxx>]

There were two problems with original code:

1. sd_booted() was used to determined if the process was started by
   systemd, which was wrong.
2. Exit with error if pidfile was specified, which was too harsh.

These two combined made cxenstored unable to start by hand if it ran
on a system which had systemd.

Fix issues with following changes:

1. Use sd_listen_fds to determine if the process is started by systemd.
2. Don't exit if pidfile is specified.

Rename function and restructure code to make things clearer.

Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
---
For 4.6: without this cxenstored is broken when running on a system with
systemd but not started by systemd.
---
 tools/xenstore/xenstored_core.c | 27 +++++++++++++++++++--------
 1 file changed, 19 insertions(+), 8 deletions(-)

diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c
index b7e4936..57581e0 100644
--- a/tools/xenstore/xenstored_core.c
+++ b/tools/xenstore/xenstored_core.c
@@ -1781,7 +1781,10 @@ static int xs_validate_active_socket(const char 
*connect_to)
        return xs_get_sd_fd(connect_to);
 }
 
-static void xen_claim_active_sockets(int **psock, int **pro_sock)
+/* Return true if started by systemd and false if not. Exit with
+ * error if things go wrong.
+ */
+static bool systemd_checkin(int **psock, int **pro_sock)
 {
        int *sock, *ro_sock;
        const char *soc_str = xs_daemon_socket();
@@ -1789,7 +1792,11 @@ static void xen_claim_active_sockets(int **psock, int 
**pro_sock)
        int n;
 
        n = sd_listen_fds(0);
-       if (n <= 0) {
+
+       if (n == 0)
+               return false;
+
+        if (n < 0) {
                sd_notifyf(0, "STATUS=Failed to get any active sockets: %s\n"
                           "ERRNO=%i",
                           strerror(errno),
@@ -1816,6 +1823,8 @@ static void xen_claim_active_sockets(int **psock, int 
**pro_sock)
 
        talloc_set_destructor(sock, destroy_fd);
        talloc_set_destructor(ro_sock, destroy_fd);
+
+       return true;
 }
 #endif
 
@@ -1929,6 +1938,9 @@ int main(int argc, char *argv[])
        bool no_domain_init = false;
        const char *pidfile = NULL;
        int timeout;
+#if defined(XEN_SYSTEMD_ENABLED)
+       bool systemd;
+#endif
 
        while ((opt = getopt_long(argc, argv, "DE:F:HNPS:t:T:RLVW:", options,
                                  NULL)) != -1) {
@@ -1990,10 +2002,11 @@ int main(int argc, char *argv[])
                barf("%s: No arguments desired", argv[0]);
 
 #if defined(XEN_SYSTEMD_ENABLED)
-       if (sd_booted()) {
+       systemd = systemd_checkin(&sock, &ro_sock);
+       if (systemd) {
                dofork = false;
                if (pidfile)
-                       barf("%s: PID file not needed on systemd", argv[0]);
+                       xprintf("%s: PID file not needed on systemd", argv[0]);
                pidfile = NULL;
        }
 #endif
@@ -2020,9 +2033,7 @@ int main(int argc, char *argv[])
        signal(SIGPIPE, SIG_IGN);
 
 #if defined(XEN_SYSTEMD_ENABLED)
-       if (sd_booted())
-               xen_claim_active_sockets(&sock, &ro_sock);
-       else
+       if (!systemd)
 #endif
                init_sockets(&sock, &ro_sock);
 
@@ -2057,7 +2068,7 @@ int main(int argc, char *argv[])
        xenbus_notify_running();
 
 #if defined(XEN_SYSTEMD_ENABLED)
-       if (sd_booted()) {
+       if (systemd) {
                sd_notify(1, "READY=1");
                fprintf(stderr, SD_NOTICE "xenstored is ready\n");
        }
-- 
2.1.4


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel