babeltrace(1): handle SIGINT to cancel the graph gracefully

It goes like this:

1. Ctrl+C
2. SIGINT
3. sigint_handler()
4. Cancel the application's graph.
5. bt_graph_run() eventually returns BT_GRAPH_STATUS_CANCELED or
   BT_GRAPH_STATUS_AGAIN.
6. When we get those statuses, we check if the graph is canceled and
   quit the loop if so.

Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

diff --git a/cli/babeltrace.c b/cli/babeltrace.c
index 03d6589124c4ca4ea0bd0909743c97fdc23a256d..4f1f8b1f4d4a1852cbd438a2be870f1c66b40456 100644 (file)
--- a/cli/babeltrace.c
+++ b/cli/babeltrace.c
@@ -49,6 +49,7 @@
 #include <glib.h>
 #include <inttypes.h>
 #include <unistd.h>
+#include <signal.h>
 #include "babeltrace-cfg.h"
 #include "babeltrace-cfg-cli-args.h"
 #include "babeltrace-cfg-cli-args-default.h"
@@ -58,11 +59,29 @@
 
 #define ENV_BABELTRACE_WARN_COMMAND_NAME_DIRECTORY_CLASH "BABELTRACE_CLI_WARN_COMMAND_NAME_DIRECTORY_CLASH"
 
+/* Application's processing graph (weak) */
+static struct bt_graph *the_graph;
+static bool canceled = false;
+
 GPtrArray *loaded_plugins;
 
 BT_HIDDEN
 int bt_cli_log_level = BT_LOG_NONE;
 
+static
+void sigint_handler(int signum)
+{
+       if (signum != SIGINT) {
+               return;
+       }
+
+       if (the_graph) {
+               bt_graph_cancel(the_graph);
+       }
+
+       canceled = true;
+}
+
 static
 void init_static_data(void)
 {
@@ -1326,6 +1345,7 @@ void cmd_run_ctx_destroy(struct cmd_run_ctx *ctx)
        }
 
        BT_PUT(ctx->graph);
+       the_graph = NULL;
        ctx->cfg = NULL;
 }
 
@@ -1347,6 +1367,7 @@ int cmd_run_ctx_init(struct cmd_run_ctx *ctx, struct bt_config *cfg)
                goto error;
        }
 
+       the_graph = ctx->graph;
        ret = bt_graph_add_port_added_listener(ctx->graph,
                graph_port_added_listener, ctx);
        if (ret) {
@@ -1581,6 +1602,10 @@ int cmd_run(struct bt_config *cfg)
                goto error;
        }
 
+       if (canceled) {
+               goto end;
+       }
+
        BT_LOGI_STR("Running the graph.");
 
        /* Run the graph */
@@ -1590,7 +1615,17 @@ int cmd_run(struct bt_config *cfg)
                switch (graph_status) {
                case BT_GRAPH_STATUS_OK:
                        break;
+               case BT_GRAPH_STATUS_CANCELED:
+                       BT_LOGI("Graph was canceled by user: status=%d",
+                               graph_status);
+                       goto error;
                case BT_GRAPH_STATUS_AGAIN:
+                       if (bt_graph_is_canceled(ctx.graph)) {
+                               BT_LOGI("Graph was canceled by user: status=%d",
+                                       graph_status);
+                               goto error;
+                       }
+
                        if (cfg->cmd_data.run.retry_duration_us > 0) {
                                BT_LOGV("Got BT_GRAPH_STATUS_AGAIN: sleeping: "
                                        "time-us=%" PRIu64,
@@ -1678,6 +1713,20 @@ set_level:
        bt_cli_log_level = log_level;
 }
 
+void set_sigint_handler(void)
+{
+       struct sigaction new_action, old_action;
+
+       new_action.sa_handler = sigint_handler;
+       sigemptyset(&new_action.sa_mask);
+       new_action.sa_flags = 0;
+       sigaction(SIGINT, NULL, &old_action);
+
+       if (old_action.sa_handler != SIG_IGN) {
+               sigaction(SIGINT, &new_action, NULL);
+       }
+}
+
 int main(int argc, const char **argv)
 {
        int ret;
@@ -1685,6 +1734,7 @@ int main(int argc, const char **argv)
        struct bt_config *cfg;
 
        init_log_level();
+       set_sigint_handler();
        init_static_data();
        cfg = bt_config_cli_args_create_with_default(argc, argv, &retcode);
 

diff --git a/lib/graph/graph.c b/lib/graph/graph.c
index 808296f74f52c0828bf4c95468158d18d71506a9..ab6b14cfb047c296d0db4183932220525ee4c0ec 100644 (file)
--- a/lib/graph/graph.c
+++ b/lib/graph/graph.c
@@ -588,11 +588,6 @@ enum bt_graph_status bt_graph_run(struct bt_graph *graph)
        }
 
        do {
-               if (graph->canceled) {
-                       status = BT_GRAPH_STATUS_CANCELED;
-                       goto end;
-               }
-
                status = bt_graph_consume(graph);
                if (status == BT_GRAPH_STATUS_AGAIN) {
                        /*