trace-cmd: Add ftrace options with fgraph tailprint option

Added internal options for ftrace, and included a fgraph:tailprint
option that will print the function names at the function exit.
When the option is set, instead of just '}' the name will
be added '} /* func_name */'

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

4 files changed, 66 insertions, 14 deletions

diff --git a/trace-cmd.h b/trace-cmd.h
index b8137b5..cec0072 100644
--- a/trace-cmd.h
+++ b/trace-cmd.h
@@ -207,6 +207,8 @@ void tracecmd_stop_recording(struct tracecmd_recorder *recorder);
 void tracecmd_stat_cpu(struct trace_seq *s, int cpu);
 
 /* --- Plugin handling --- */
+extern struct plugin_option trace_ftrace_options[];
+
 void trace_util_add_option(const char *name, const char *val);
 void trace_util_load_plugins(struct pevent *pevent, const char *suffix,
                              void (*load_plugin)(struct pevent *pevent,
diff --git a/trace-ftrace.c b/trace-ftrace.c
index 193e85d..76aef5b 100644
--- a/trace-ftrace.c
+++ b/trace-ftrace.c
@@ -25,6 +25,20 @@
 
 #include "trace-cmd.h"
 
+struct plugin_option trace_ftrace_options[] = {
+        {
+                .name = "tailprint",
+                .plugin_alias = "fgraph",
+                .description =
+                "Print function name at function exit in function graph",
+        },
+        {
+                .name = NULL,
+        }
+};
+
+static struct plugin_option *fgraph_tail = &trace_ftrace_options[0];
+
 static void find_long_size(struct tracecmd_ftrace *finfo)
 {
         finfo->long_size = tracecmd_long_size(finfo->handle);
@@ -290,6 +304,8 @@ fgraph_ret_handler(struct trace_seq *s, struct record *record,
         struct tracecmd_ftrace *finfo = context;
         unsigned long long rettime, calltime;
         unsigned long long duration, depth;
+        unsigned long long val;
+        const char *func;
         int i;
 
         ret_event_check(finfo, event->pevent);
@@ -317,6 +333,15 @@ fgraph_ret_handler(struct trace_seq *s, struct record *record,
 
         trace_seq_putc(s, '}');
 
+        if (fgraph_tail->set) {
+                if (pevent_get_field_val(s, event, "func", record, &val, 0))
+                        return 0;
+                func = pevent_find_function(event->pevent, val);
+                if (!func)
+                        return 0;
+                trace_seq_printf(s, " /* %s */", func);
+        }
+
         return 0;
 }
 
diff --git a/trace-input.c b/trace-input.c
index c3b58b1..97459eb 100644
--- a/trace-input.c
+++ b/trace-input.c
@@ -2173,6 +2173,9 @@ struct tracecmd_input *tracecmd_alloc_fd(int fd)
         /* register default ftrace functions first */
         tracecmd_ftrace_overrides(handle, &handle->finfo);
 
+        /* Add the ftrace options */
+        trace_util_ftrace_options();
+
         handle->plugin_list = tracecmd_load_plugins(handle->pevent);
 
         handle->pevent->file_bigendian = buf[0];
diff --git a/trace-util.c b/trace-util.c
index 04cb087..de59a3f 100644
--- a/trace-util.c
+++ b/trace-util.c
@@ -61,6 +61,18 @@ struct plugin_list {
         void                    *handle;
 };
 
+static void update_option(const char *file, struct plugin_option *option);
+
+void trace_util_ftrace_options(void)
+{
+        struct plugin_option *options = trace_ftrace_options;
+
+        while (options->name) {
+                update_option("ftrace", options);
+                options++;
+        }
+}
+
 void trace_util_add_option(const char *name, const char *val)
 {
         struct trace_plugin_options *option;
@@ -909,12 +921,28 @@ struct plugin_option_read {
         struct plugin_option    *options;
 };
 
+static void append_option(struct plugin_option_read *options,
+                          struct plugin_option *option,
+                          const char *alias, void *handle)
+{
+        struct plugin_option *op;
+
+        while (option->name) {
+                op = malloc_or_die(sizeof(*op));
+                *op = *option;
+                op->next = options->options;
+                options->options = op;
+                op->file = strdup(alias);
+                op->handle = handle;
+                option++;
+        }
+}
+
 static void read_options(struct pevent *pevent, const char *path,
                          const char *file, void *data)
 {
-        struct plugin_option_read *option = data;
-        struct plugin_option *options;
-        struct plugin_option *op;
+        struct plugin_option_read *options = data;
+        struct plugin_option *option;
         const char *alias;
         int unload = 0;
         char *plugin;
@@ -937,21 +965,13 @@ static void read_options(struct pevent *pevent, const char *path,
         if (!alias)
                 alias = file;
 
-        options = dlsym(handle, PEVENT_PLUGIN_OPTIONS_NAME);
-        if (!options) {
+        option = dlsym(handle, PEVENT_PLUGIN_OPTIONS_NAME);
+        if (!option) {
                 unload = 1;
                 goto out_unload;
         }
 
-        while (options->name) {
-                op = malloc_or_die(sizeof(*op));
-                *op = *options;
-                op->next = option->options;
-                option->options = op;
-                op->file = strdup(alias);
-                op->handle = handle;
-                options++;
-        }
+        append_option(options, option, alias, handle);
 
  out_unload:
         if (unload)
@@ -966,6 +986,8 @@ struct plugin_option *trace_util_read_plugin_options(void)
                 .options = NULL,
         };
 
+        append_option(&option, trace_ftrace_options, "ftrace", NULL);
+
         trace_util_load_plugins(NULL, ".so", read_options, &option);
 
         return option.options;