MINOR: stream/cli: add another filter "susp" to "show sess"

This one reports streams considered as "suspicious", i.e. those with
no expiration dates or dates in the past, or those without a front
endpoint. More criteria could be added in the future.

doc/management.txt

@@ -3144,13 +3144,15 @@ show sess
   the last one that was created before the command was entered; those which
   die in the mean time will not appear.
 
-show sess <id> | older <age> | all
+show sess <id> | older <age> | susp | all
   Display a lot of internal information about the matching sessions. In the
   first form, only the session matching the specified session identifier will
   be shown. This identifier is the first field at the beginning of the lines in
   the dumps of "show sess" (it corresponds to the session pointer). In the
   second form, only sessions older than <age> (in seconds by default) will be
-  shown. If "all" is used instead, then all sessions will be dumped. Dumping
+  shown. Passing "susp" instead will only report entries that are considered as
+  suspicious by the developers based on criteria that may in time or vary along
+  versions. If "all" is used instead, then all sessions will be dumped. Dumping
   many sessions can produce a huge output, take a lot of time and be CPU
   intensive, so it's always better to only dump the minimum needed. Those
   information are useless to most users but may be used by haproxy developers

src/stream.c

@@ -3109,13 +3109,16 @@ void list_services(FILE *out)
 }
 
 /* appctx context used by the "show sess" command */
+/* flags used for show_sess_ctx.flags */
+#define CLI_SHOWSESS_F_SUSP  0x00000001   /* show only suspicious streams */
 
 struct show_sess_ctx {
 	struct bref bref;	/* back-reference from the session being dumped */
 	void *target;		/* session we want to dump, or NULL for all */
 	unsigned int thr;       /* the thread number being explored (0..MAX_THREADS-1) */
 	unsigned int uid;	/* if non-null, the uniq_id of the session being dumped */
 	unsigned int min_age;   /* minimum age of streams to dump */
+	unsigned int flags;     /* CLI_SHOWSESS_* */
 	int section;		/* section of the session being dumped */
 	int pos;		/* last position of the current session's buffer */
 };
@@ -3532,6 +3535,10 @@ static int cli_parse_show_sess(char **args, char *payload, struct appctx *appctx
 		ctx->min_age = timeout;
 		ctx->target = (void *)-1; /* show all matching entries */
 	}
+	else if (*args[2] && strcmp(args[2], "susp") == 0) {
+		ctx->flags |= CLI_SHOWSESS_F_SUSP;
+		ctx->target = (void *)-1; /* show all matching entries */
+	}
 	else if (*args[2] && strcmp(args[2], "all") == 0)
 		ctx->target = (void *)-1;
 	else if (*args[2])
@@ -3619,6 +3626,16 @@ static int cli_io_handler_dump_sess(struct appctx *appctx)
 				goto next_sess;
 		}
 
+		if (ctx->flags & CLI_SHOWSESS_F_SUSP) {
+			/* only show suspicious streams. Non-suspicious ones have a valid
+			 * expiration date in the future and a valid front endpoint.
+			 */
+			if (curr_strm->task->expire &&
+			    !tick_is_expired(curr_strm->task->expire, now_ms) &&
+			    curr_strm->scf && curr_strm->scf->sedesc && curr_strm->scf->sedesc->se)
+				goto next_sess;
+		}
+
 		if (ctx->target) {
 			if (ctx->target != (void *)-1 && ctx->target != curr_strm)
 				goto next_sess;
@@ -3845,7 +3862,7 @@ static int cli_parse_shutdown_sessions_server(char **args, char *payload, struct
 
 /* register cli keywords */
 static struct cli_kw_list cli_kws = {{ },{
-	{ { "show", "sess",  NULL },             "show sess [<id>|all|older <age>]        : report the list of current sessions or dump this exact session", cli_parse_show_sess, cli_io_handler_dump_sess, cli_release_show_sess },
+	{ { "show", "sess",  NULL },             "show sess [<id>|all|susp|older <age>]   : report the list of current sessions or dump this exact session", cli_parse_show_sess, cli_io_handler_dump_sess, cli_release_show_sess },
 	{ { "shutdown", "session",  NULL },      "shutdown session [id]                   : kill a specific session",                                        cli_parse_shutdown_session, NULL, NULL },
 	{ { "shutdown", "sessions",  "server" }, "shutdown sessions server <bk>/<srv>     : kill sessions on a server",                                      cli_parse_shutdown_sessions_server, NULL, NULL },
 	{{},}