File Reset-delay-for-unixsock-connect-from-inotify.p... of Package conman

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File Reset-delay-for-unixsock-connect-from-inotify.patch of Package conman (Revision c79742a07e6e1cfa372de64a647b416c)

Currently displaying revision c79742a07e6e1cfa372de64a647b416c , Show latest

From: Egbert Eich <eich@suse.com>
Date: Wed Jul 18 11:26:07 2018 +0200
Subject: Reset delay for unixsock connect from inotify
Patch-mainline: Not yet
Git-repo: https://github.com/dun/conman
Git-commit: 8f5bd09162307a23efb8532a95c4e4a562ce30fe
References: bsc#1101647

Consoles over UNIX domain sockets use inotify to detect when their
socket appears in the filesystem.  This inotify event is triggered
when the remote has successfully called bind().  However, the remote
may not have called listen() before the inotify event is serviced
by conmand.  In such a case, connect() will fail with ECONNREFUSED,
after which the connection delay will be increased before the next
connection attempt.  This can result in connection establishment
taking up to UNIXSOCK_MAX_TIMEOUT seconds once the socket appears.

To handle this case, reset the connection delay to UNIXSOCK_MIN_TIMEOUT
when a connection attempt triggered by inotify fails.

[cdunlap@llnl.gov: Restructured to use isViaInotify flag]
Signed-off-by: Egbert Eich <eich@suse.com>
Signed-off-by: Chris Dunlap <cdunlap@llnl.gov>
Closes #28
Closes #29
Signed-off-by: Egbert Eich <eich@suse.de>
---
 server-unixsock.c | 36 ++++++++++++++++++++++++++++++++++--
 server.h          |  1 +
 2 files changed, 35 insertions(+), 2 deletions(-)
diff --git a/server-unixsock.c b/server-unixsock.c
index e683ec7..b44adb4 100644
--- a/server-unixsock.c
+++ b/server-unixsock.c
@@ -45,6 +45,7 @@
 #include "util-str.h"
 
 
+static int open_unixsock_obj_via_inotify(obj_t *unixsock);
 static size_t max_unixsock_dev_strlen(void);
 static int connect_unixsock_obj(obj_t *unixsock);
 static int disconnect_unixsock_obj(obj_t *unixsock);
@@ -140,6 +141,7 @@ obj_t * create_unixsock_obj(server_conf_t *conf, char *name, char *dev,
     unixsock->aux.unixsock.logfile = NULL;
     unixsock->aux.unixsock.timer = -1;
     unixsock->aux.unixsock.state = CONMAN_UNIXSOCK_DOWN;
+    unixsock->aux.unixsock.isViaInotify = 0;
     unixsock->aux.unixsock.delay = UNIXSOCK_MIN_TIMEOUT;
     /*
      *  Add obj to the master conf->objs list.
@@ -147,7 +149,7 @@ obj_t * create_unixsock_obj(server_conf_t *conf, char *name, char *dev,
     list_append(conf->objs, unixsock);
 
     rv = inevent_add(unixsock->aux.unixsock.dev,
-        (inevent_cb_f) open_unixsock_obj, unixsock);
+        (inevent_cb_f) open_unixsock_obj_via_inotify, unixsock);
     if (rv < 0) {
         log_msg(LOG_INFO,
             "Console [%s] unable to register device \"%s\" for inotify events",
@@ -177,6 +179,23 @@ int open_unixsock_obj(obj_t *unixsock)
 }
 
 
+static int open_unixsock_obj_via_inotify(obj_t *unixsock)
+{
+/*  Opens the specified 'unixsock' obj via an inotify callback.
+ *  Returns 0 if the console is successfully opened; o/w, returns -1.
+ */
+    unixsock_obj_t *auxp;
+
+    assert(unixsock != NULL);
+    assert(is_unixsock_obj(unixsock));
+
+    auxp = &(unixsock->aux.unixsock);
+    auxp->isViaInotify = 1;
+
+    return(open_unixsock_obj(unixsock));
+}
+
+
 static size_t max_unixsock_dev_strlen(void)
 {
 /*  Returns the maximum string length allowed for a unix domain device.
@@ -199,6 +218,7 @@ static int connect_unixsock_obj(obj_t *unixsock)
  *  Returns 0 if the connection is successfully completed; o/w, returns -1.
  */
     unixsock_obj_t     *auxp;
+    int                 isViaInotify;
     struct stat         st;
     struct sockaddr_un  saddr;
     size_t              n;
@@ -210,6 +230,9 @@ static int connect_unixsock_obj(obj_t *unixsock)
 
     auxp = &(unixsock->aux.unixsock);
 
+    isViaInotify = auxp->isViaInotify;
+    auxp->isViaInotify = 0;
+
     if (auxp->timer >= 0) {
         (void) tpoll_timeout_cancel(tp_global, auxp->timer);
         auxp->timer = -1;
@@ -250,11 +273,20 @@ static int connect_unixsock_obj(obj_t *unixsock)
     set_fd_nonblocking(unixsock->fd);
     set_fd_closed_on_exec(unixsock->fd);
 
-    /*  FIXME: Check to see if connect() on a nonblocking unix domain socket
+    /*  If a connect() triggered via an inotify event fails, reset the
+     *    reconnect delay to its minimum to quickly re-attempt the connection.
+     *    This handles the case where the remote has successfully called bind()
+     *    (triggering the inotify event) but has not yet called listen().
+     *  FIXME: Check to see if connect() on a nonblocking unix domain socket
      *    can return EINPROGRESS.  I don't think it can.
      */
     if (connect(unixsock->fd,
             (struct sockaddr *) &saddr, sizeof(saddr)) < 0) {
+        if (isViaInotify) {
+            auxp->delay = UNIXSOCK_MIN_TIMEOUT;
+            DPRINTF((15, "Reset [%s] reconnect delay due to inotify event\n",
+                unixsock->name));
+        }
         log_msg(LOG_INFO, "Console [%s] cannot connect to device \"%s\": %s",
             unixsock->name, auxp->dev, strerror(errno));
         return(disconnect_unixsock_obj(unixsock));
diff --git a/server.h b/server.h
index 8ccbcf9..6cc7c1b 100644
--- a/server.h
+++ b/server.h
@@ -180,6 +180,7 @@ typedef struct unixsock_obj {           /* UNIXSOCK AUX OBJ DATA:            */
     int              timer;             /*  timer id for reconnects          */
     int              delay;             /*  secs 'til next reconnect attempt */
     unsigned         state:1;           /*  unixsock_state_t conn state      */
+    unsigned         isViaInotify:1;    /*  true if triggered via inotify    */
 } unixsock_obj_t;
 
 /*  Refer to struct ipmiconsole_ipmi_config in <ipmiconsole.h>.

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File Reset-delay-for-unixsock-connect-from-inotify.patch of Package conman (Revision c79742a07e6e1cfa372de64a647b416c)

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