From cdbc9afe5da5fe728ce8fa62e36ded17efe70032 Mon Sep 17 00:00:00 2001 From: Neels Hofmeyr Date: Tue, 3 Apr 2018 16:51:49 +0200 Subject: 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 --- include/osmocom/ctrl/control_cmd.h | 3 +++ src/ctrl/control_cmd.c | 1 + src/ctrl/control_if.c | 7 +++++++ tests/ctrl/ctrl_test.c | 4 ---- tests/ctrl/ctrl_test.ok | 3 ++- 5 files changed, 13 insertions(+), 5 deletions(-) diff --git a/include/osmocom/ctrl/control_cmd.h b/include/osmocom/ctrl/control_cmd.h index 865b006b..a5df753d 100644 --- a/include/osmocom/ctrl/control_cmd.h +++ b/include/osmocom/ctrl/control_cmd.h @@ -56,6 +56,8 @@ struct ctrl_connection { struct llist_head def_cmds; }; +struct ctrl_cmd_def; + struct ctrl_cmd { struct ctrl_connection *ccon; enum ctrl_type type; @@ -64,6 +66,7 @@ struct ctrl_cmd { char *variable; char *value; char *reply; + struct ctrl_cmd_def *defer; }; #define ctrl_cmd_reply_printf(cmd, fmt, args ...) \ diff --git a/src/ctrl/control_cmd.c b/src/ctrl/control_cmd.c index c747e84d..fb0cd2b7 100644 --- a/src/ctrl/control_cmd.c +++ b/src/ctrl/control_cmd.c @@ -566,6 +566,7 @@ ctrl_cmd_def_make(const void *ctx, struct ctrl_cmd *cmd, void *data, unsigned in cd = talloc_zero(ctx, struct ctrl_cmd_def); + cmd->defer = cd; cd->cmd = cmd; cd->data = data; diff --git a/src/ctrl/control_if.c b/src/ctrl/control_if.c index 07de0d46..df8abbc6 100644 --- a/src/ctrl/control_if.c +++ b/src/ctrl/control_if.c @@ -401,6 +401,13 @@ int ctrl_handle_msg(struct ctrl_handle *ctrl, struct ctrl_connection *ccon, stru if (cmd->type != CTRL_TYPE_ERROR) { cmd->ccon = ccon; if (ctrl_cmd_handle(ctrl, cmd, ctrl->data) == CTRL_CMD_HANDLED) { + + if (cmd->defer) { + /* The command is still stored as ctrl_cmd_def.cmd, in the def_cmds list. + * Just leave hanging for deferred handling. Reply will happen later. */ + return 0; + } + /* On CTRL_CMD_HANDLED, no reply needs to be sent back. */ talloc_free(cmd); cmd = NULL; diff --git a/tests/ctrl/ctrl_test.c b/tests/ctrl/ctrl_test.c index f20f534c..b7b30c3e 100644 --- a/tests/ctrl/ctrl_test.c +++ b/tests/ctrl/ctrl_test.c @@ -401,8 +401,6 @@ static void test_deferred_cmd() /* Expecting a ctrl_cmd_def as well as the cmd to still be allocated */ if (talloc_total_size(ctx) <= ctx_size_before_defer) { printf("deferred command apparently deallocated too soon\n"); - /* ERROR -- showing current bug in handling deallocated cmds, hence exiting early */ - goto exit_early; talloc_report_full(ctx, stdout); OSMO_ASSERT(false); } @@ -417,8 +415,6 @@ static void test_deferred_cmd() OSMO_ASSERT(false); } -exit_early: - talloc_free(ccon); talloc_free(ctrl); diff --git a/tests/ctrl/ctrl_test.ok b/tests/ctrl/ctrl_test.ok index 6a902be0..07f4aac5 100644 --- a/tests/ctrl/ctrl_test.ok +++ b/tests/ctrl/ctrl_test.ok @@ -176,5 +176,6 @@ ok test_deferred_cmd get_test_defer called ctrl_handle_msg() returned 0 -deferred command apparently deallocated too soon +invoking ctrl_test_defer_cb() asynchronously +ctrl_test_defer_cb called success -- cgit v1.2.3