ctrl: fix deferred commands (and hence fix osmo-bts-sysmo 'clock-info' cmd)
The CTRL interface has a ctrl_cmd_def_* API that allows deferring a CTRL
command reply until later. However, the command handling currently fails to
acknowledge this and deallocates the struct ctrl_cmd anyway.
Fix: in struct ctrl_cmd, add a defer pointer to be populated by
ctrl_cmd_def_make(). A cmd thus marked as deferred is not deallocated at the
end of command handling. This fix needs no change in calling code.
(Another idea was to return a different code than CTRL_CMD_HANDLED when the
command is to be deferred, but that would require adjusting each user of
ctrl_cmd_def_make(). The implicit marking is safer and easier.)
Show that handling deferred commands is fixed by adjusting the expectations of
ctrl_test.c's test_deferred_cmd() and removing the now obsolete exit_early
label.
One symptom of the breakage is that osmo-bts-sysmo crashes when asked to report
a trx's clock-info, which is aggravated by the fact that the sysmobts-mgr does
ask osmo-bts-sysmo for a clock-info.
The crash appears since Id583b413f8b8bd16e5cf92a8a9e8663903646381 -- it looked
like just fixing an obvious memory leak, which it did as shown by the unit
test, but deferred ctrl commands actually relied on that leak. Both fixed now.
Related: OS#3120
Change-Id: I24232be7dcf7be79f4def91ddc8b8f8005b56318
diff --git a/include/osmocom/ctrl/control_cmd.h b/include/osmocom/ctrl/control_cmd.h
index 865b006..a5df753 100644
--- a/include/osmocom/ctrl/control_cmd.h
+++ b/include/osmocom/ctrl/control_cmd.h
@@ -56,6 +56,8 @@
struct llist_head def_cmds;
};
+struct ctrl_cmd_def;
+
struct ctrl_cmd {
struct ctrl_connection *ccon;
enum ctrl_type type;
@@ -64,6 +66,7 @@
char *variable;
char *value;
char *reply;
+ struct ctrl_cmd_def *defer;
};
#define ctrl_cmd_reply_printf(cmd, fmt, args ...) \