trace-cmd: Fix trace-cmd function graph handling of its events

The function graph needs to store the function graph return event
for later use. This patch changes the function graph callbacks
to use the context to store this information and initialize it
when first referenced.

The event data is now stored on the tracecmd_input handle, that allows
more than one tracecmd_input handle to work with this code in one
utility.

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

3 files changed, 73 insertions, 26 deletions

diff --git a/trace-cmd.h b/trace-cmd.h
index 901a843..dda4d0b 100644
--- a/trace-cmd.h
+++ b/trace-cmd.h
@@ -77,6 +77,13 @@ enum {
         TRACECMD_OPTION_DONE,
 };
 
+struct tracecmd_ftrace {
+        struct tracecmd_input           *handle;
+        struct event_format *fgraph_ret_event;
+        int fgraph_ret_id;
+        int long_size;
+};
+
 struct tracecmd_input *tracecmd_alloc(const char *file);
 struct tracecmd_input *tracecmd_alloc_fd(int fd);
 struct tracecmd_input *tracecmd_open(const char *file);
@@ -138,7 +145,7 @@ int tracecmd_set_cursor(struct tracecmd_input *handle,
 unsigned long long
 tracecmd_get_cursor(struct tracecmd_input *handle, int cpu);
 
-int tracecmd_ftrace_overrides(struct tracecmd_input *handle);
+int tracecmd_ftrace_overrides(struct tracecmd_input *handle, struct tracecmd_ftrace *finfo);
 struct pevent *tracecmd_get_pevent(struct tracecmd_input *handle);
 
 #ifndef SWIG
diff --git a/trace-ftrace.c b/trace-ftrace.c
index f12b221..f11fb6f 100644
--- a/trace-ftrace.c
+++ b/trace-ftrace.c
@@ -25,9 +25,36 @@
 
 #include "trace-cmd.h"
 
-static struct event_format *fgraph_ret_event;
-static int fgraph_ret_id;
-static int long_size;
+static void find_long_size(struct tracecmd_ftrace *finfo)
+{
+        finfo->long_size = tracecmd_long_size(finfo->handle);
+}
+
+#define long_size_check(handle)                         \
+        do {                                            \
+                if (!finfo->long_size)                          \
+                        find_long_size(finfo);          \
+        } while (0)
+
+static int find_ret_event(struct tracecmd_ftrace *finfo, struct pevent *pevent)
+{
+        struct event_format *event;
+
+        /* Store the func ret id and event for later use */
+        event = pevent_find_event_by_name(pevent, "ftrace", "funcgraph_exit");
+        if (!event)
+                return -1;
+
+        finfo->fgraph_ret_id = event->id;
+        finfo->fgraph_ret_event = event;
+        return 0;
+}
+
+#define ret_event_check(finfo, pevent)                                  \
+        do {                                                            \
+                if (!finfo->fgraph_ret_event && find_ret_event(finfo, pevent) < 0) \
+                        return -1;                                      \
+        } while (0)
 
 static int function_handler(struct trace_seq *s, struct record *record,
                             struct event_format *event, void *context)
@@ -61,27 +88,28 @@ static int function_handler(struct trace_seq *s, struct record *record,
 
 static struct record *
 get_return_for_leaf(struct trace_seq *s, int cpu, int cur_pid,
-                    unsigned long long cur_func, struct record *next)
+                    unsigned long long cur_func, struct record *next,
+                    struct tracecmd_ftrace *finfo)
 {
         unsigned long long val;
         unsigned long long type;
         unsigned long long pid;
 
         /* Searching a common field, can use any event */
-        if (pevent_get_common_field_val(s, fgraph_ret_event, "common_type", next, &type, 1))
+        if (pevent_get_common_field_val(s, finfo->fgraph_ret_event, "common_type", next, &type, 1))
                 return NULL;
 
-        if (type != fgraph_ret_id)
+        if (type != finfo->fgraph_ret_id)
                 return NULL;
 
-        if (pevent_get_common_field_val(s, fgraph_ret_event, "common_pid", next, &pid, 1))
+        if (pevent_get_common_field_val(s, finfo->fgraph_ret_event, "common_pid", next, &pid, 1))
                 return NULL;
 
         if (cur_pid != pid)
                 return NULL;
 
         /* We aleady know this is a funcgraph_ret_event */
-        if (pevent_get_field_val(s, fgraph_ret_event, "func", next, &val, 1))
+        if (pevent_get_field_val(s, finfo->fgraph_ret_event, "func", next, &val, 1))
                 return NULL;
 
         if (cur_func != val)
@@ -146,7 +174,8 @@ static void print_graph_duration(struct trace_seq *s, unsigned long long duratio
 static int
 print_graph_entry_leaf(struct trace_seq *s,
                        struct event_format *event,
-                       struct record *record, struct record *ret_rec)
+                       struct record *record, struct record *ret_rec,
+                       struct tracecmd_ftrace *finfo)
 {
         struct pevent *pevent = event->pevent;
         unsigned long long rettime, calltime;
@@ -155,11 +184,10 @@ print_graph_entry_leaf(struct trace_seq *s,
         const char *func;
         int i;
 
-
-        if (pevent_get_field_val(s, fgraph_ret_event, "rettime", ret_rec, &rettime, 1))
+        if (pevent_get_field_val(s, finfo->fgraph_ret_event, "rettime", ret_rec, &rettime, 1))
                 return trace_seq_putc(s, '!');
 
-        if (pevent_get_field_val(s, fgraph_ret_event, "calltime", ret_rec, &calltime, 1))
+        if (pevent_get_field_val(s, finfo->fgraph_ret_event, "calltime", ret_rec, &calltime, 1))
                 return trace_seq_putc(s, '!');
 
         duration = rettime - calltime;
@@ -225,10 +253,13 @@ static int
 fgraph_ent_handler(struct trace_seq *s, struct record *record,
                    struct event_format *event, void *context)
 {
+        struct tracecmd_ftrace *finfo = context;
         struct record *rec;
         unsigned long long val, pid;
         int cpu = record->cpu;
 
+        ret_event_check(finfo, event->pevent);
+
         if (pevent_get_common_field_val(s, event, "common_pid", record, &pid, 1))
                 return trace_seq_putc(s, '!');
 
@@ -237,14 +268,14 @@ fgraph_ent_handler(struct trace_seq *s, struct record *record,
 
         rec = tracecmd_peek_data(tracecmd_curr_thread_handle, cpu);
         if (rec)
-                rec = get_return_for_leaf(s, cpu, pid, val, rec);
+                rec = get_return_for_leaf(s, cpu, pid, val, rec, finfo);
 
         if (rec) {
                 /*
                  * If this is a leaf function, then get_return_for_leaf
                  * returns the return of the function
                  */
-                print_graph_entry_leaf(s, event, record, rec);
+                print_graph_entry_leaf(s, event, record, rec, finfo);
                 free_record(rec);
         } else
                 print_graph_nested(s, event, record);
@@ -256,10 +287,13 @@ static int
 fgraph_ret_handler(struct trace_seq *s, struct record *record,
                    struct event_format *event, void *context)
 {
+        struct tracecmd_ftrace *finfo = context;
         unsigned long long rettime, calltime;
         unsigned long long duration, depth;
         int i;
 
+        ret_event_check(finfo, event->pevent);
+
         if (pevent_get_field_val(s, event, "rettime", record, &rettime, 1))
                 return trace_seq_putc(s, '!');
 
@@ -290,6 +324,7 @@ static int
 trace_stack_handler(struct trace_seq *s, struct record *record,
                     struct event_format *event, void *context)
 {
+        struct tracecmd_ftrace *finfo = context;
         struct format_field *field;
         unsigned long long addr;
         const char *func;
@@ -304,11 +339,13 @@ trace_stack_handler(struct trace_seq *s, struct record *record,
 
         trace_seq_puts(s, "<stack trace>\n");
 
-        for (i = 0; i < field->size; i += long_size) {
+        long_size_check(finfo);
+
+        for (i = 0; i < field->size; i += finfo->long_size) {
                 addr = pevent_read_number(event->pevent,
-                                          data + field->offset + i, long_size);
+                                          data + field->offset + i, finfo->long_size);
 
-                if ((long_size == 8 && addr == (unsigned long long)-1) ||
+                if ((finfo->long_size == 8 && addr == (unsigned long long)-1) ||
                     ((int)addr == -1))
                         break;
 
@@ -322,7 +359,8 @@ trace_stack_handler(struct trace_seq *s, struct record *record,
         return 0;
 }
 
-int tracecmd_ftrace_overrides(struct tracecmd_input *handle)
+int tracecmd_ftrace_overrides(struct tracecmd_input *handle,
+        struct tracecmd_ftrace *finfo)
 {
         struct pevent *pevent;
         struct event_format *event;
@@ -333,23 +371,23 @@ int tracecmd_ftrace_overrides(struct tracecmd_input *handle)
                                       function_handler, NULL);
 
         pevent_register_event_handler(pevent, -1, "ftrace", "funcgraph_entry",
-                                      fgraph_ent_handler, NULL);
+                                      fgraph_ent_handler, finfo);
 
         pevent_register_event_handler(pevent, -1, "ftrace", "funcgraph_exit",
-                                      fgraph_ret_handler, NULL);
+                                      fgraph_ret_handler, finfo);
 
         pevent_register_event_handler(pevent, -1, "ftrace", "kernel_stack",
-                                      trace_stack_handler, NULL);
+                                      trace_stack_handler, finfo);
 
         /* Store the func ret id and event for later use */
         event = pevent_find_event_by_name(pevent, "ftrace", "funcgraph_exit");
         if (!event)
                 return 0;
 
-        long_size = tracecmd_long_size(handle);
+        finfo->long_size = tracecmd_long_size(handle);
 
-        fgraph_ret_id = event->id;
-        fgraph_ret_event = event;
+        finfo->fgraph_ret_id = event->id;
+        finfo->fgraph_ret_event = event;
 
         return 0;
 }
diff --git a/trace-input.c b/trace-input.c
index 398d0f9..b3dbca3 100644
--- a/trace-input.c
+++ b/trace-input.c
@@ -82,6 +82,8 @@ struct tracecmd_input {
         int                     ref;
         struct cpu_data         *cpu_data;
 
+        struct tracecmd_ftrace  finfo;
+
         /* file information */
         size_t                  header_files_start;
         size_t                  ftrace_files_start;
@@ -1976,7 +1978,7 @@ struct tracecmd_input *tracecmd_alloc_fd(int fd)
                 goto failed_read;
 
         /* register default ftrace functions first */
-        tracecmd_ftrace_overrides(handle);
+        tracecmd_ftrace_overrides(handle, &handle->finfo);
 
         handle->plugin_list = tracecmd_load_plugins(handle->pevent);